WO2024079319A1 - Rank restriction for multi-panel ul transmission - Google Patents

Abstract

A method, system and apparatus for rank restriction for multi-panel uplink (UL) transmission are disclosed. According to one aspect, a method in a wireless device (WD) includes receiving, from a network node, a downlink control information (DCI) message that includes two fields each of which includes a rank indicator for one of two sounding reference signal (SRS) resource sets configured for the WD. The method includes determining a rank for each of the two SRS resource sets of the WD based at least in part on the rank indicator.

Description

RANK RESTRICTION FOR MULTI-PANEL UL TRANSMISSION

TECHNICAL FIELD

The present disclosure relates to wireless communications, and in particular, to rank restriction for multi-panel uplink (UL) transmission.

BACKGROUND

The Third Generation Partnership Project (3 GPP) has developed and is developing standards for Fourth Generation (4G) (also referred to as Long Term Evolution (LTE)) and Fifth Generation (5G) (also referred to as New Radio (NR)) wireless communication systems. Such systems provide, among other features, broadband communication between network nodes, such as base stations, and mobile wireless devices (WD), as well as communication between network nodes and between WDs. The 3GPP is also developing standards for Sixth Generation (6G) wireless communication networks. Beam management

At mmW frequencies, concepts for handling mobility between beams (both within and between transmission/reception points (TRPs)) have been specified in NR. At these frequencies, where high-gain beamforming is used, each beam is only optimal within a small area, and the link budget outside the optimal beam deteriorates quickly. Hence, frequent and fast beam switching may be needed to maintain high performance. To support such beam switching, a beam indication framework has been specified in NR. For example, for downlink data transmission (physical downlink shared channel (PDSCH)), the downlink control information (DCI) contains a transmission configuration indicator (TCI) field that informs the WD which beam is used so that it may adjust its receive beam accordingly. This is beneficial for the case of analog receive (Rx) beamforming where the WD needs to determine and apply the Rx beamforming weights before it may receive the PDSCH.

As used herein, the terminology “spatial filtering weights” or “spatial filtering configuration,” refer to the antenna weights that are applied at either the transmitter (network node or WD) and the receiver (WD or network node) for data/control transmission/reception. This term is more general in the sense that different propagation environments lead to different spatial filtering weights that match the transmission/reception of a signal to the channel. The spatial filtering weights may not always result in a beam in a strict sense. Prior to data transmission, a training phase is required in order to determine the network node and WD spatial fdtering configurations. This is illustrated in FIG. 1 and is referred to in NR as downlink (DL) beam management. In NR, two types of reference signals (RSs) are used for DL beam management operations, the channel state information RS (CSI-RS) and the synchronization signal/physical broadcast control channel (SS/PBCH) block, or SSB for short. FIG. 1 shows an example where CSI-RS is used to find an appropriate beam pair link (BPL), meaning a suitable network node transmit spatial filtering configuration (network node transmit (Tx) beam) plus a suitable WD receive spatial filtering configuration (UE Rx beam) resulting in sufficiently good link budget.

FIG. 1 shows an example of a beam training phase followed by data transmission phase. For downlink data/control transmission, the network node indicates to the WD that the physical downlink control channel (PDCCH)/PDSCH demodulation reference signal (DMRS) is spatially quasi-co-located (QCL) with RS6 - the RS on which the WD performs measurements during the WD beam sweep in the beam training phase. At least for uplink control channel transmission, the network node indicates to the WD that RS6 is the spatial relation for the physical uplink control channel (PUCCH).

In the above example, in the network node Tx beam sweep, the network node configures the WD to measure on a set of 5 CSI-RS resources (RSI .. RS5) which are transmitted with 5 different spatial filtering configurations (Tx beams). The WD is also configured to report back the RS ID and the reference-signal receive power (RSRP) of the CSI-RS corresponding to the maximum measured RSRP. In this example, the maximum measured RSRP corresponds to RS4. In this way the network node learns what is the preferred Tx beam from the WD perspective. In the subsequent WD Rx beam sweep, the network node transmits a number of CSI-RS resources in different orthogonal frequency division multiplexed (OFDM) symbols all with the same spatial filtering configuration (Tx beam) as was used to transmit RS4 previously. The WD then tests a different Rx spatial filtering configuration (Rx beam) in each OFDM symbol in order to maximize the received RSRP. The WD remembers the RS ID (RS ID 6 in this example) and the corresponding spatial filtering configuration that results in the largest RSRP. The network may then refer to this RS ID in the future when DL data is scheduled to the WD, thus allowing the WD to adjust its Rx spatial filtering configuration (Rx beam) to receive the PDSCH. As mentioned above, the RS ID is contained in a transmission configuration indicator (TCI) that is carried in a field in the DCI that schedules the PDSCH

Data transmission over multiple transmission/reception points (TRP) or panels

A PDSCH may be transmitted to a WD from multiple TRPs. Since different TRPs may be located in different physical locations and have different beams, the propagation channels may be different. To facilitate receiving PDSCH data from different TRPs or beams, a WD may be configured by radio resource control (RRC) with multiple transmission configuration indicator (TCI) states. A TCI state contains Quasi Co-location (QCL) information between the DMRS for PDSCH and one or two DL reference signals such as non-zero power (NZP) CSI-RS or synchronization signal block (SSB). Different NZP CSI-RSs or synchronization signal blocks (SSB) may be associated with different TRPs or beams. The QCL information may be used by a WD to apply large scale channel properties associated with the DL reference signals (NZP CSLRS or SSB) to DMRS of PDSCH for channel estimation and PDSCH reception.

The supported QCL information types in NR may include:

• 'QCL-TypeA': {Doppler shift, Doppler spread, average delay, delay spread};

• 'QCL-TypeB': {Doppler shift, Doppler spread};

• 'QCL-TypeC: {Doppler shift, average delay}; and

• 'QCL-TypeD': {Spatial Rx parameter}.

A subset of the RRC configured TCI states may be activated by medium access control (MAC) control element (CE) for PDSCH. From the activated TCI states, one or two of them may be dynamically selected and indicated in the DCI scheduling a PDSCH depending on over which TRP(s) or beam(s) the PDSCH is transmitted. Each codepoint of the TCI field in DCI may indicate either 1 TCI state or two TCI states. A TCI field codepoint indicating 1 TCI state may be used to transmit PDSCH from a single TRP or single beam. If a TCI field codepoint indicates 2 TCI states, then PDSCH may be transmitted from two TRPs or two beams.

Physical Uplink Shared Channel (PUSCH)

There are two transmission schemes specified for PUSCH: codebook (CB)-based precoding and non-codebook (NCB)-based precoding. The network node configures, by radio resource control (RRC), the transmission scheme through the higher-layer parameter txConfigure in the PUSCH-Configure IE. CB-based transmission may be used for non-calibrated WDs and/or for frequency division duplex (FDD) (i.e., uplink (UL)ZDL reciprocity does not need to hold). NCB-based transmission, on the other hand, relies on UL/DL reciprocity and is, hence, intended for time division duplex (TDD). CB -based precoding

CB-based PUSCH is enabled if the higher-layer parameter txConfigure is set to ‘codebook’. For dynamically scheduled PUSCH with configured grant type 2, CB-based PUSCH transmission may be summarized in the following steps:

• The WD transmits sounding reference signals (SRS), configured in an SRS resource set with higher-layer parameter usage in SRS-Configure IE set to ‘codebook’. Up to two SRS resources (for testing up to two virtualizations/beams/panels) each with up to four ports, may be configured in the SRS resource set;

• The network node determines the number of layers (or rank) and a preferred precoder (i.e., transmission precoder matrix indicator (TPMI)) from a codebook subset based on the received SRS from one of the SRS resources. The codebook subset is configured via the higher-layer parameter codebookSubset, based on reported WD capability, and is one of:

1. fully coherent (‘fully AndPartialAndNonCoherent’);

2. partially coherent (‘partialAndNonCoherent’); or

3. non-coh erent (‘noncoherent’);

• If two SRS resources are configured in the SRS resource set, the network node indicates the selected SRS resource via a 1 -bit SRI field in the DCI scheduling the PUSCH transmission. If only one SRS resource is configured in the SRS resource set, the SRI field is not indicated in DCI;

• The network node indicates, via DCI, the number of layers and the TPMI. DM- RS port(s) associated with the layer(s) are also indicated in DCI. The number of bits in DCI used for indicating the number of layers (if transform precoding is enabled, the number of PUSCH layers is limited to 1) and the TPMI is determined as follows (unless UL full-power transmission is configured, for which the number of bits may vary):

■ 4, 5, or 6 bits if the number of antenna ports is 4, if transform precoding is disabled, and if the higher-layer parameter maxRank in PUSCH- Configure IE is set to 2, 3, or 4;

■ 2, 4, or 5 bits if the number of antenna ports is 4, if transform precoding is disabled or enabled, and if the higher-layer parameter maxRank in PUSCH-Configure IE is set to 1;

■ 2 or 4 bits if the number of antenna ports is 2, if transform precoding is disabled, and if the higher-layer parameter maxRank in PUSCH- Configure IE is set to 2;

■ 1 or 3 bits if the number of antenna ports is 2, if transform precoding is disabled or enabled, and if the higher-layer parameter maxRank in PUSCH-Configure IE is set to 1 : and

• 0 bits if 1 antenna port is used for PUSCH transmission; o The WD performs PUSCH transmission over the antenna ports corresponding to the SRS ports in the indicated SRS resource.

NCB-based precoding

NCB-based UL transmission is for reciprocity-based UL transmission in which SRS precoding is derived at a WD based on CSI-RS received in the DL. Specifically, the WD measures received CSI-RS and deduces suitable precoder weights for SRS transmission(s), resulting in one or more (virtual) SRS ports, each corresponding to a spatial layer.

A WD may be configured up to four sounding reference signal (SRS) resources, each with a single (virtual) SRS port, in an SRS resource set with higher-layer parameter usage in SRS-Configure IE set to ‘nonCodebook’. A WD transmits the up to four SRS resources and the network node measures the UL channel based on the received SRS and determines the preferred SRS resource(s). Next, the network node indicates the selected SRS resources via the SRS resource indictor (SRI) field in DCI and the WD uses this information to precode PUSCH with a transmission rank that equals the number of indicated SRS resources (and, hence, the number of SRS ports). The SRI field in DCI is determined as follows: bits, where /V_SRS is the number of

configured SRS resources in the SRS resource set configured by higher layer parameter srs-ResourceSetToAddModList, and associated with the higher layer parameter usage of value 'codeBook' or 'nonCodeBook': o bits according to Tables 7.3.1.1.2-

28/29/30/31 if the higher layer parameter txConfigure = nonCodebook, where /V_SRS is the number of configured SRS resources in the SRS resource set configured by higher layer parameter srs-ResourceSetToAddModList, and associated with the higher layer parameter usage of value 'nonCodeBook'; and

■ if WD supports operation with maxMIMO-Layers and the higher layer parameter maxMIMO-Layers of PUSCH-ServingCellConfigure of the serving cell is configured, Lmax is given by that parameter;

■ otherwise, Lmax is given by the maximum number of layers for PUSCH supported by the WD for the serving cell for non-codebook based operation; o log A^ bits according to Tables 7.3.1.1.2-32, 7.3.1.1.2-32A and 7.3.1.1.2-32B if the higher layer parameter txConfigure = codebook, where A_SRS is the number of configured SRS resources in the SRS resource set configured by higher layer parameter srs-ResourceSetToAddModList, and associated with the higher layer parameter usage of value 'codeBook'.

SRS

In NR, SRS is used for providing CSI to the network node in the UL. The usage of SRS includes, e.g., deriving the appropriate transmission/reception beams and/or to perform link adaptation (i.e., setting the transmission rank and the modulation and coding scheme (MCS)), and for selecting DL (e.g., for PDSCH transmissions) and UL (e.g., for PUSCH transmissions) multiple input-multiple output (MIMO) precoding.

In LTE and NR, the SRS is configured via RRC, where parts of the configuration may be updated (for reduced latency) through MAC-CE signaling. The configuration includes, for example, the SRS resource allocation (the physical mapping and the sequence to use) as well as the time-domain behavior (aperiodic, semi-persistent, or periodic). For aperiodic SRS transmission, the RRC configuration does not activate an SRS transmission from the WD but instead, a dynamic activation trigger is transmitted from the network node in the DL via the DCI in the PDCCH which instructs the WD to transmit the SRS once, at a predetermined time.

When configuring SRS transmissions, the network node configures, through the SRS-Configure information element (IE), a set of SRS resources and a set of SRS resource sets, where each SRS resource set contains one or more SRS resources. SRS configuration

Each SRS resource is configured with the following in RRC (for example see ASN code in 3GPP Technical Specification (TS) 38.331 version 16.1.0):

SRS -Resource ::= SEQUENCE { srs-Resourceld SRS-Resourceld, nrofSRS-Ports ENUMERATED {portl, ports2, ports4}, ptrs-Portlndex ENUMERATED {n0, nl } OPTIONAL, - Need R transmissionComb CHOICE { n2 SEQUENCE { combOffset-n2 INTEGER (0..1), cyclicShift-n2 INTEGER (0..7)

}, n4 SEQUENCE { combOffset-n4 INTEGER (0..3), cyclicShift-n4 INTEGER (0 . 11)

}

resourceMapping SEQUENCE { startPosition INTEGER (0..5), nrofSymbols ENUMERATED {nl, n2, n4}, repetitionF actor ENUMERATED {nl, n2, n4{

freqDomainPosition INTEGER (0..67), freqDomainShift INTEGER (0..268), freqHopping SEQUENCE { c-SRS INTEGER (0 .63), b-SRS INTEGER (0..3), b-hop INTEGER (0 .3)

groupOrSequenceHopping ENUMERATED { neither, groupHopping, sequenceHopping }, resourceType CHOICE { aperiodic SEQUENCE {

}, semi-persistent SEQUENCE { peri odi city AndOffset- sp SRS -Peri odi city AndOffset.

}, periodic SEQUENCE { periodi city AndOffset-p SRS -Periodi city AndOff set,

}

sequenceld INTEGER (0..1023), spatialRelationlnfo SRS-SpatialRelationlnfo OPTIONAL, -

Need R

resourceMapping-r!6 SEQUENCE { startPosition-r!6 INTEGER (0 . 13), nrofSymbols-rl6 ENUMERATED {nl, n2, n4}, repetitionF actor-r 16 ENUMERATED {nl, n2, n4}

OPTIONAL

— Need R

]]

An SRS resource is configurable with respect to, e.g.:

• The number of SRS ports (1, 2, or 4), configured by the RRC parameter nrofSRS- Ports;

• The transmission comb (i.e., mapping to every 2nd or 4th subcarrier), configured by the RRC parameter transmissionComb, which may include one or more of: o The comb offset, configured by the RRC parameter combOffset, is specified (i.e., which of the combs that should be used); o The cyclic shift, configured by the RRC parameter cyclicShift, that configures a (port-specific, for multi-port SRS resources) cyclic shift for the Zadoff-Chu sequence that is used for SRS. The use of cyclic shifts increases the number of SRS resources that may be mapped to a comb (as SRS sequences are designed to be (almost) orthogonal under cyclic shifts), but there is a limit on how many cyclic shifts that may be used (8 for comb 2 and 12 for comb 4);

• The time-domain position within a given slot, configured with the RRC parameter resourceMapping, which may include: o The time-domain start position, which is limited to be one of the last 6 symbols (in NR 3GPP Rel-15) or in any of the 14 symbols in a slot (in NR 3GPP Rel-16), configured by the RRC parameter startPosition; o The number of symbols for the SRS resource (that may be set to 1, 2 or 4), configured by the RRC parameter nrofSymbols; o The repetition factor (that may be set to 1, 2 or 4), configured by the RRC parameter repetitionF actor. When the repetition factor is larger than 1, the same frequency resources are used multiple times across symbols, used to improve the coverage as this allows more energy to be collected by the receiver;

• The sounding bandwidth, frequency-domain position and shift, and frequencyhopping pattern of an SRS resource (i.e., which part of the transmission bandwidth that is occupied by the SRS resource) is set through the RRC parameters freqDomainPosition, freqDomain Shift, and the freqHopping parameters c-SRS, b- SRS, and b-hop. The smallest possible sounding bandwidth is 4 RBs;

• The RRC parameter resourceType determines whether the SRS resource is transmitted as periodic, aperiodic (singe transmission triggered by DCI), or semi persistent (same as periodic except for the start and stop of the periodic transmission is controlled through MAC-CE signaling instead of RRC signaling);

• The RRC parameter sequenceld specifies how the SRS sequence is initialized; and

• The RRC parameter spatialRelationlnfo configures the spatial relation for the SRS beam with respect to another RS (which may be another SRS, an SSB or a CSI-RS). If an SRS resource has a spatial relation to another SRS resource, then this SRS resource should be transmitted with the same beam (i.e., virtualization) as the indicated SRS resource.

An illustration of how an SRS resource may be allocated in time and frequency within a slot (note that semi-persistent/periodic SRS resources typically span several slots), is provided in FIG. 2. In NR 3GPP Technical Release 16 (3GPP Rel-16), the additional (and optional) RRC parameter resourceMapping-rl6 was introduced. If resourceMapping-rl6 is signaled, the WD will ignore the RRC parameter resourceMapping. The difference between resourceMapping-rl6 and resourceMapping is that the SRS resource (for which the number of OFDM symbols and the repetition factor is still limited to 4) may start in any of the 14 OFDM symbols in a slot configured by the RRC parameter startPosition-rl6.

An SRS resource set is configured with the following in RRC (for example, see ASN code in 3GPP TS 38.331 version 16.1.0).

SRS -ResourceSet ::= SEQUENCE ) srs-ResourceSetld SRS-ResourceSetld, srs-ResourceldList SEQUENCE (SIZE(1. maxNrofSRS-

ResourcesPerSet)) OF SRS-Resourceld OPTIONAL, — Cond Setup resourceType CHOICE { aperiodic SEQUENCE { aperiodicSRS-ResourceTrigger INTEGER (1..maxNrofSRS- Trigger States- 1), csi-RS NZP-CSI-RS-Resourceld

OPTIONAL, — Cond NonCodebook slotOffset INTEGER (1..32)

OPTIONAL, - Need S

[[ aperiodicSRS-ResourceTriggerList SEQUENCE

(SIZE(l..maxNrofSRS-TriggerStates-2))

OF INTEGER (1 maxNrofSRS-

Trigger States- 1) OPTIONAL — Need M

]]

}, semi-persistent SEQUENCE { associatedCSI-RS NZP-CSI-RS-Resourceld

OPTIONAL, — Cond NonCodebook

}, periodic SEQUENCE { associatedCSI-RS NZP-CSI-RS-Resourceld

OPTIONAL, — Cond NonCodebook

usage ENUMERATED {beamManagement, codebook, nonCodebook, antennaSwitching}, alpha Alpha OPTIONAL, -

Need S pO INTEGER (-202. 24) OPTIONAL,

— Cond Setup pathlossReferenceRS PathlossReferenceRS-Configure

OPTIONAL, - Need M srs-PowerControlAdjustm entStates ENUMERATED { sameAsFci2, separateClosedLoop} OPTIONAL, — Need S

[[ pathlossReferenceRSList-rl6 SetupRelease { PathlossReferenceRSList- rl6} OPTIONAL - Need M

]]

}

SRS resource(s) will be transmitted as part of an SRS resource set, where all SRS resources in the same SRS resource set must share the same resource type. An SRS resource set is configurable with respect to, e g.:

• For aperiodic SRS, the slot offset is configured by the RRC parameter slotOffset and sets the delay from the PDCCH trigger reception to the start of the SRS transmission;

• The resource usage, which is configured by the RRC parameter usage sets constraints and assumptions on the resource properties (see 3GPP TS 38.214 V17.3.0 for further details). SRS resource sets may be configured with one of four different usages: ‘antennaSwitching’, ‘codebook’, ‘nonCodebook’ and ‘beamManagement’; o An SRS resource set that is configured with usage ‘antennaSwitching’ is used for reciprocity-based DL precoding (i.e., used to sound the channel in the UL so that the network node may use reciprocity to set a suitable DL precoders). The WD is expected to transmit one SRS port per WD antenna port; o An SRS resource set that is configured with usage ‘codebook’ is used for CB- based UL transmission (i.e., used to sound the different WD antennas and help the network node to determine/signal a suitable UL precoder, transmission rank, and MCS for PUSCH transmission). There are up to two SRS resources in an SRS resource set with usage ‘codebook’. How SRS ports are mapped to WD antenna ports is, however, up to WD implementation and not known to the network node; o An SRS resource set that is configured with usage ‘nonCodebook’ is used for NCB-based UL transmission. Specifically, the WD transmits one SRS resource per candidate beam (suitable candidate beams are determined by the WD based on CSI-RS measurements in the DL and, hence, reciprocity needs to hold). The network node may then, by indicating a subset of these SRS resources, determine which UL beam(s) that the WD should apply for PUSCH transmission. One UL layer will be transmitted per indicated SRS resource. Note that how the WD maps SRS ports to antenna ports is up to WD implementation and not known to the network node; o An SRS resource set that is configured with usage ‘beamManagemenf is used (mainly for frequency bands above 6 GHz (i.e., for FR2)) to evaluate different WD beams for analog beamforming arrays. The WD transmits one SRS resource per analog beam, and the network node will perform an RSRP measurement per transmitted SRS resource and, in this way, determine a suitable WD beam that is reported to the WD. It is expected that the network node configures one SRS resource set with usage ‘beamManagemenf for each analog array (i.e., panel) that the WD has; and

• The associated CSI-RS (this configuration is only applicable for NCB-based UL transmission) for each of the possible resource types: o For an aperiodic SRS, the associated CSI-RS resource is set by the RRC parameter csi-RS; and o For semi-persistent/periodic SRS, the associated CSI-RS resource is set by the RRC parameter associatedCSLRS; and

• The PC parameters, e.g., alpha and pO are used for setting the SRS transmission power. SRS has its own UL PC scheme in NR (see 3GPP TS 38.213 V17.3.0 for further details), which specifies how the WD should split the available output power between two or more SRS ports during one SRS transmit occasion (an SRS transmit occasion is a time window within a slot where SRS transmission is performed).

To summarize, the SRS resource-set configuration determines, e.g., usage, power control, and slot offset for aperiodic SRS. The SRS resource configuration determines the time-and-frequency allocation, the periodicity and offset, the sequence, and the spatial-relation information.

UL Transmission to Multiple Transmission/Reception Points (TRPs)

PDSCH transmission with multiple transmission points has been introduced in 3 GPP for NR 3GPP Rel-16, in which a transport block may be transmitted over multiple TRPs to improve transmission reliability.

In NR 3GPP Rel-17, UL enhancement with multiple TRPs is introduced by transmitting a PUSCH towards to different TRPs. This is shown in FIG. 3 at different times (i.e., PUSCH transmissions to different TRPs are transmitted in time division multiplexed, TDM, fashion).

In one scenario, multiple PUSCH transmissions each towards a different TRP may be scheduled by a single DCI. An example of PUSCH repetitions is shown in FIG. 4 where two PUSCH repetitions for a same transport block (TB) are scheduled by a single DCI, each PUSCH occasion is transmitted towards a different TRP.

In 3GPP Rel-17, multi-TRP PUSCH, 3GPP Rel-16 single TRP based type A and type B PUSCH repetitions are extended to two TRPs or two beams. The two beams are mapped to different PUSCH repetitions with either a cyclical mapping pattern or a sequential mapping pattern.

In case of cyclic mapping pattern, the first and second beams are applied to the first and second PUSCH repetitions, respectively, and the same beam mapping pattern continues to the remaining PUSCH repetitions. Cyclic mapping is used in case of two repetitions. For more than 2 repetitions, cyclic mapping is a WD capability.

In case of sequential mapping pattern, the first beam is applied to the first and second PUSCH repetitions, and the second beam is applied to the third and fourth PUSCH repetitions, and the same beam mapping pattern continues to the remaining PUSCH repetitions.

An example is shown in FIG. 5 for a cyclic mapping pattern and FIG. 6 for a sequential mapping pattern. For Type B PUSCH repetition, the mapping is done based on nominal repetitions.

Both codebook based and non-codebook based PUSCH are supported with multi- TRP PUSCH. Two SRS resource sets are introduced for the purpose. The same number SRS resources should be configured in the two SRS resource sets.

When scheduling PUSCH, two SRS resource indicators (SRIs) are indicated to a WD, each associated one of the two SRS resource sets. For codebook based PUSCH, two transmit precoding matrix indicators (TPMIs) are also indicated to the WD, each associated one of the two SRS resource sets. For dynamic scheduled PUSCH or type 2 Configured Grants (CGs), the two SRIs and TPMIs are signaled in DCI. For type 1 CG, additional SRI and TPMI fields are included in CG configuration.

For codebook based multi-TRP PUSCH repetition, the number of SRS ports indicated by the two SRIs should be the same.

Dynamic switching between multi-TRP and single-TRP PUSCH operation is supported with a new 2 bit field in DCI as shown in Table 1. The TRP towards which the first PUSCH repetition is transmitted may also be indicated with codepoint “10” for the first TRP or “11” for the second TRP. The new 2 bit field in DCI is referred to as ‘ SRS resource set indicator’ field in 3GPP TS 38.212 V17.0.0.

Table 1 : A new DCI field for dynamic switching between single TRP and multi- TRP PUSCH

The SRS resource set with lower ID is the first SRS resource set, and the other SRS resource set is the second SRS resource set. Association of a SRS resource set to a PUSCH transmission occasion

When two SRS resource sets are configured in srs-ResourceSetToAddModList or srs-ResourceSetToAddModListDCI-0-2 with higher layer parameter usage in SRS- ResourceSet set to 'codebook' or 'noncodebook', for PUSCH repetition Type A, in case K>1 (where K is the number of repetitions), the same symbol allocation is applied across the K consecutive slots and the PUSCH is limited to a single transmission layer. The WD will repeat the TB (Transport Block) across the K consecutive slots applying the same symbol allocation in each slot, and the association of the first and second SRS resource set in srs-ResourceSetToAddModList or srs-ResourceSetToAddModListDCI-0-2 to each slot may be determined as follows: if a DCI format 0 1 or DCI format 0 2 indicates codepoint "00" for the SRS resource set indicator, the first SRS resource set is associated with all K consecutive slots; if a DCI format 0 1 or DCI format 0 2 indicates codepoint "01" for the SRS resource set indicator, the second SRS resource set is associated with all K consecutive slots; if a DCI format 0 1 or DCI format 0 2 indicates codepoint " 10" for the SRS resource set indicator, the first and second SRS resource set association to K consecutive slots is determined as follows:

When K = 2, the first and second SRS resource sets are applied to the first and second slot of 2 consecutive slots, respectively;

When K > 2 and cyclicMapping in PUSCH-Configure is enabled, the first and second SRS resource sets are applied to the first and second slot of K consecutive slots, respectively, and the same SRS resource set mapping pattern continues to the remaining slots of K consecutive slots;

When K > 2 and sequentialMapping in PUSCH-Configure is enabled, first SRS resource set is applied to the first and second slots of K consecutive slots, and the second SRS resource set is applied to the third and fourth slot of K consecutive slots, and the same SRS resource set mapping pattern continues to the remaining slots of K consecutive slots:

Otherwise, a DCI format 0 1 or DCI format 0 2 indicates codepoint "11" for the SRS resource set indicator, and the first and second SRS resource set association to K consecutive slots is determined as follows:

When K = 2, the second and first SRS resource set are applied to the first and second slot of 2 consecutive slots, respectively;

When K > 2 and cyclicMapping in PUSCH-Configure is enabled, the second and first SRS resource sets are applied to the first and second slot of K consecutive slots, respectively, and the same SRS resource set mapping pattern continues to the remaining slots of the K consecutive slots; and

When K > 2 and sequentialMapping in PUSCH-Configure is enabled, the second SRS resource set is applied to the first and second slot of K consecutive slots, and the first SRS resource set is applied to the third and fourth slot of K consecutive slots, and the same SRS resource set mapping pattern continues to the remaining slots of the K consecutive slots.

For PUSCH repetition Type B, when two SRS resource sets are configured in srs- ResourceSetToAddModList or srs-ResourceSetToAddModListDCI-0-2 with higher layer parameter usage in SRS-ResourceSet set to 'codebook' or 'noncodebook', the SRS resource set association to nominal PUSCH repetitions follows the same method as SRS resource set association to slots in PUSCH Type A repetition by considering nominal repetitions instead of slots.

Simultaneous multi-panel transmission (STxMP)

In NR up to 3GPP Rel-17, considerations regarding UL transmission for FR2 have mainly been for a WD with single panel transmission (transmission from a single WD panel at each time instance). In NR 3GPP Rel-18, it has been considered to specify support for up to two simultaneously transmitting WD panels. In 3GPP Rel-18, it was considered that a space division multiplexing (SDM) scheme should be supported for single-DCI UL multi-panel transmission and based on support in 3GPP from many companies it is likely that also SFN-based scheme should be supported for STxMP. There are also considerations ongoing in 3GPP on how to support dynamic switching between STxMP transmission modes and single WD panel transmission. In a similar way, there are considerations whether to support dynamic switching between STxMP in 3GPP Rel-18 and multi-TRP repetition schemes specified in 3GPP Rel-17 (for example, PUSCH TDM repetition).

In addition, there are also considerations in 3GPP regarding the number of supported layers per WD panel during STxMP, where the most likely outcome is to support the following candidate number of layers: (1,1), (1,2), (2,1) and (2,2).

As may be seen in the background section the size (and interpretation) of the TPMI field/SRI field in DCI 0 1 and DCI 0 2 depends on for example the maximum rank that the WD may be configured with for the associated PUSCH, i.e., the configured value of the parameter “maxRank” in PUSCH-configure (for example, as specified in 3GPP TS 38.331 V17.2.0) for codebook based UL transmission, and on the configured value of the parameter “maxMIMO-Layers” in PUSCH-ServingCellConfigure (as specified in 3GPP TS 38.331 V17.2.0) for non-codebook based UL transmission.

The size of the temporary multi-media identity (TPMI)/scheduling request indicator (SRI) field for codebook-based UL transmission also depends on the number of SRS port/SRS resources configured in an SRS resource set for usage ‘codebook’ and in a similar way the size of the SRI field for non-codebook-based UL transmission also depends on the number of SRS resources configured in an SRS resource set for usage ‘nonCodebook’.

How to determine the size (and interpretation) of the TPMI/SRI field in DCI for STxMP where two separate TPMI/SRI fields are used, one per TRP, will be based on for example the maximum rank configured per SRS resource set for a WD configured for STxMP operation. However, how to configure the maximum rank for STxMP operation is an open issue.

SUMMARY

Some embodiments advantageously provide methods, network nodes and wireless devices for rank restriction for multi-panel uplink (UL) transmission.

This disclosure describes several methods to configure the maximum rank for STxMP operation, for example by indicating maximum rank, and/or minimum rank, and/or the available ranks per SRS resource set or combined over both SRS resource sets, considering different UL transmission schemes (like STxMP SDM, STxMP single frequency network (SFN), etc.).

In future cellular networks, it is possible that more than two WD panels will be used for simultaneous transmission, especially for high-capable WDs, and for example in D-multiple input-multiple output (MIMO) applications where different WD panels are transmitting to different access points (APs). It is also possible that a WD panel supports more than 2 layers per panel, which is likely to be the maximum number of layers per panel considered in NR for STxMP. Hence, some of the embodiments disclosed herein may be relevant also for 6G, since it is expected that downlink control signaling (similar to downlink control information (DCI) in NR) overhead for rank and precoder indication for UL data transmission for such high-capable WDs will be a larger issue. Hence, methods to reduce the DL control signaling overhead will be needed. By configuring the candidate ranks for STxMP operation per TRP (or WD panel/SRS resource set), the DCI overhead may be reduced for PUSCH transmission. Also, the interpretation of the codepoints of the TPMI/SRI fields in DCI will be clarified for the WD (removes potential ambiguity).

According to one aspect, a WD, configured to communicate with a network node is provided. The WD is configured to receive, from the network node, a downlink control information, DCI, message that carries two fields each of which includes a rank indicator for one of two sounding reference signal (SRS) resource sets configured for the WD. The WD is also configured to determine a rank for each of the two SRS resource sets of the WD based at least in part on the rank indicator.

According to this aspect, in some embodiments, the two fields are sounding reference signal resource indicator, SRI, fields for non-codebook operation. In some embodiments, the two fields are transmit precoder matrix indicator, TPMI, fields for codebook operation. In some embodiments, determining a rank for each of the two SRS resource sets of the WD is further based at least in part on a maximum supported rank per SRS resource set of the WD. In some embodiments, the WD is configured to receive, a single parameter indicating the maximum supported rank per SRS resource set of the WD, wherein the single parameter applies to both of the two SRS resource sets. In some embodiments, the single parameter indicates a maximum rank per SRS resource set for SFN Simultaneous multi-panel transmission (STxMP) operation. In some embodiments, each SRS resource set is associated with a corresponding panel of the WD which is capable of STxMP operation. In some embodiments, a first SRS resource set is associated with a first transmission configuration indicator, TCI, state and a first transmission precoder matrix indicator/SRS resource indicator, TPMI/SRI, field and a second SRS resource set is associated with a second TCI state and a second TPMI/SRI field.

According to another aspect, a method in a wireless device, WD, configured to communicate with a network node is provided. The method includes receiving, from the network node, a downlink control information, DCI, message that carries two fields each of which includes a rank indicator for one of two SRS resource sets configured for the WD. The method also includes determining a rank for each of the two SRS resource sets of the WD based at least in part on the rank indicator.

According to this aspect, In some embodiments, the two fields are sounding reference signal resource indicator, SRI, fields for non-codebook operation. In some embodiments, the two fields are transmit precoder matrix indicator, TPMI, fields for codebook operation. In some embodiments, determining a rank for each of the two SRS resource sets of the WD is further based at least in part on a maximum supported rank per SRS resource set of the WD. In some embodiments, the method includes receiving a single parameter indicating the maximum supported rank per SRS resource set of the WD, wherein the single parameter applies to both of the two SRS resource sets. In some embodiments, the single parameter indicates a maximum rank per SRS resource set for SFN STxMP operation. In some embodiments, each SRS resource set is associated with a corresponding panel of the WD being capable of STxMP operation. According to yet another aspect, a network node configured to communicate with a wireless device, WD, is provided. The network node is configured to: configure a downlink control information, DCI, message that includes two fields, each field including a rank indicator for one of two sounding reference signal, SRS, resource sets configured for the WD; and transmit the DCI message to the WD.

According to this aspect, in some embodiments, the two fields are sounding reference signal resource indicator, SRI, fields for non-codebook operation. In some embodiments, the two fields are transmit precoder matrix indicator, TPMI, fields for codebook operation. In some embodiments, the network node is configured to: configure the WD with a maximum supported rank per SRS resource set of the WD (22), via a single parameter indicating the maximum supported rank applying to both of the two SRS resource sets. In some embodiments, the single parameter indicates maximum rank per SRS resource set for SFN STxMP operation or SDM STxMP operation

According to another aspect, a method in a network node configured to communicate with a wireless device, WD, is provided. The method includes: configuring a downlink control information, DCI, message that includes two fields, each field including a rank indicator for one of two sounding reference signal, SRS, resource sets configured for the WD; and transmitting the DCI message to the WD.

According to this aspect, in some embodiments, the two fields are sounding reference signal resource indicator, SRI, fields for non-codebook operation. In some embodiments, the method includes the two fields are transmit precoder matrix indicator, TPMI, fields for codebook operation. In some embodiments, the method includes configuring the WD with a maximum supported rank per SRS resource set of the WD (22), via a single parameter indicating the maximum supported rank applying to both of the two SRS resource sets.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein:

FIG. 1 illustrates a beam training phase followed by a data transmission phase;

FIG. 2 illustrates an SRS resource allocation;

FIG. 3 illustrates transmission of PUSCH toward different TRPs;

FIG. 4 illustrates an example of PUSCH repetitions;

FIG. 5 illustrates PUSCH repetitions for a cyclic mapping pattern;

FIG. 6 illustrates PUSCH repetitions for a sequential mapping pattern;

FIG. 7 is a schematic diagram of an example network architecture illustrating a communication system connected via an intermediate network to a host computer according to the principles in the present disclosure;

FIG. 8 is a block diagram of a host computer communicating via a network node with a wireless device over an at least partially wireless connection according to some embodiments of the present disclosure;

FIG. 9 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for executing a client application at a wireless device according to some embodiments of the present disclosure;

FIG. 10 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data at a wireless device according to some embodiments of the present disclosure;

FIG. 11 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data from the wireless device at a host computer according to some embodiments of the present disclosure;

FIG. 12 is a flowchart illustrating example methods implemented in a communication system including a host computer, a network node and a wireless device for receiving user data at a host computer according to some embodiments of the present disclosure;

FIG. 13 is a flowchart of an example process in a network node for rank restriction for multi-panel uplink (UL) transmission;

FIG. 14 is a flowchart of an example process in a wireless device for rank restriction for multi-panel uplink (UL) transmission;

FIG. 15 is a flowchart of an example process in a network node for rank restriction for multi-panel uplink (UL) transmission; and

FIG. 16 is a flowchart of an example process in a wireless device for rank restriction for multi-panel uplink (UL) transmission.

DETAILED DESCRIPTION

Before describing in detail example embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to rank restriction for multi-panel uplink (UL) transmission. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Like numbers refer to like elements throughout the description.

As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication. In some embodiments, described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and/or wireless connections.

The term “network node” used herein can be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multistandard radio (MSR) radio node such as MSR BS, multi-cell/multicast coordination entity (MCE), integrated access and backhaul (IAB) node, relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term “radio node” used herein may be used to also denote a wireless device (WD) such as a wireless device (WD) or a radio network node.

In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The WD herein can be any type of wireless device capable of communicating with a network node or another WD over radio signals, such as wireless device (WD). The WD may also be a radio communication device, target device, device to device (D2D) WD, machine type WD or WD capable of machine to machine communication (M2M), low-cost and/or low-complexity WD, a sensor equipped with WD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (loT) device, or a Narrowband loT (NB-IOT) device, etc.

Also, In some embodiments, the generic term “radio network node” is used. It can be any kind of a radio network node which may comprise any of base station, radio base station, base transceiver station, base station controller, network controller, RNC, evolved Node B (eNB), Node B, gNB, Multi-cell/multicast Coordination Entity (MCE), IAB node, relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH).

Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and/or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

Note further, that functions described herein as being performed by a wireless device or a network node may be distributed over a plurality of wireless devices and/or network nodes. In other words, it is contemplated that the functions of the network node and wireless device described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Some embodiments provide rank restriction for multi-panel uplink (UL) transmission.

Returning now to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 7 a schematic diagram of a communication system 10, according to an embodiment, such as a 3 GPP -type cellular network that may support standards such as LTE and/or NR (5G), which comprises an access network 12, such as a radio access network, and a core network 14. The access network 12 comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively as network nodes 16), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 18a, 18b, 18c (referred to collectively as coverage areas 18). Each network node 16a, 16b, 16c is connectable to the core network 14 over a wired or wireless connection 20. A first wireless device (WD) 22a located in coverage area 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16a. A second WD 22b in coverage area 18b is wirelessly connectable to the corresponding network node 16b. While a plurality of WDs 22a, 22b (collectively referred to as wireless devices 22) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole WD is in the coverage area or where a sole WD is connecting to the corresponding network node 16. Note that although only two WDs 22 and three network nodes 16 are shown for convenience, the communication system may include many more WDs 22 and network nodes 16.

Also, it is contemplated that a WD 22 may be in simultaneous communication and/or configured to separately communicate with more than one network node 16 and more than one type of network node 16. For example, a WD 22 may have dual connectivity with a network node 16 that supports LTE and the same or a different network node 16 that supports NR. As an example, WD 22 may be in communication with an eNB for LTE/E-UTRAN and a gNB for NR/NG-RAN.

The communication system 10 may itself be connected to a host computer 24, which may be embodied in the hardware and/or software of a standalone server, a cloud- implemented server, a distributed server or as processing resources in a server farm. The host computer 24 may be under the ownership or control of a service provider, or may be operated by the service provider or on behalf of the service provider. The connections 26, 28 between the communication system 10 and the host computer 24 may extend directly from the core network 14 to the host computer 24 or may extend via an optional intermediate network 30. The intermediate network 30 may be one of, or a combination of more than one of, a public, private or hosted network. The intermediate network 30, if any, may be a backbone network or the Internet. In some embodiments, the intermediate network 30 may comprise two or more sub-networks (not shown).

The communication system of FIG. 7 as a whole enables connectivity between one of the connected WDs 22a, 22b and the host computer 24. The connectivity may be described as an over-the-top (OTT) connection. The host computer 24 and the connected WDs 22a, 22b are configured to communicate data and/or signaling via the OTT connection, using the access network 12, the core network 14, any intermediate network 30 and possible further infrastructure (not shown) as intermediaries. The OTT connection may be transparent in the sense that at least some of the participating communication devices through which the OTT connection passes are unaware of routing of uplink and downlink communications. For example, a network node 16 may not or need not be informed about the past routing of an incoming downlink communication with data originating from a host computer 24 to be forwarded (e g., handed over) to a connected WD 22a. Similarly, the network node 16 need not be aware of the future routing of an outgoing uplink communication originating from the WD 22a towards the host computer 24.

A network node 16 is configured to include an STxMP unit 32 which may be configured to configure the WD for simultaneous multi-panel transmission, STxMP, according to the maximum rank. The STxMP unit 32 may be configured to configure a downlink control information, DCI, message with a sounding reference signal, SRS, resource indicator, SRI, field that includes a rank indicator from which the WD 22 determines a rank for each of multiple antenna panels of the WD. A WD 22 is configured to include a panel configuration unit 34 which may be configured to configure a number of panels for simultaneous multi-panel transmission, STxMP according to the rank parameter. The panel configuration unit 34 may be configured to determine a rank for each of multiple antenna panels of the WD based at least in part on the rank indicator.

Example implementations, in accordance with an embodiment, of the WD 22, network node 16 and host computer 24 discussed in the preceding paragraphs will now be described with reference to FIG. 2. In a communication system 10, a host computer 24 comprises hardware (HW) 38 including a communication interface 40 configured to set up and maintain a wired or wireless connection with an interface of a different communication device of the communication system 10. The host computer 24 further comprises processing circuitry 42, which may have storage and/or processing capabilities. The processing circuitry 42 may include a processor 44 and memory 46. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 42 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 44 may be configured to access (e.g., write to and/or read from) memory 46, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Processing circuitry 42 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by host computer 24. Processor 44 corresponds to one or more processors 44 for performing host computer 24 functions described herein. The host computer 24 includes memory 46 that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 48 and/or the host application 50 may include instructions that, when executed by the processor 44 and/or processing circuitry 42, causes the processor 44 and/or processing circuitry 42 to perform the processes described herein with respect to host computer 24. The instructions may be software associated with the host computer 24.

The software 48 may be executable by the processing circuitry 42. The software 48 includes a host application 50. The host application 50 may be operable to provide a service to a remote user, such as a WD 22 connecting via an OTT connection 52 terminating at the WD 22 and the host computer 24. In providing the service to the remote user, the host application 50 may provide user data which is transmitted using the OTT connection 52. The “user data” may be data and information described herein as implementing the described functionality. In some embodiments, the host computer 24 may be configured for providing control and functionality to a service provider and may be operated by the service provider or on behalf of the service provider. The processing circuitry 42 of the host computer 24 may enable the host computer 24 to observe, monitor, control, transmit to and/or receive from the network node 16 and or the wireless device 22.

The communication system 10 further includes a network node 16 provided in a communication system 10 and including hardware 58 enabling it to communicate with the host computer 24 and with the WD 22. The hardware 58 may include a communication interface 60 for setting up and maintaining a wired or wireless connection with an interface of a different communication device of the communication system 10, as well as a radio interface 62 for setting up and maintaining at least a wireless connection 64 with a WD 22 located in a coverage area 18 served by the network node 16. The radio interface 62 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers. The communication interface 60 may be configured to facilitate a connection 66 to the host computer 24. The connection 66 may be direct or it may pass through a core network 14 of the communication system 10 and/or through one or more intermediate networks 30 outside the communication system 10.

In the embodiment shown, the hardware 58 of the network node 16 further includes processing circuitry 68. The processing circuitry 68 may include a processor 70 and a memory 72. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 68 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 70 may be configured to access (e.g., write to and/or read from) the memory 72, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the network node 16 further has software 74 stored internally in, for example, memory 72, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the network node 16 via an external connection. The software 74 may be executable by the processing circuitry 68. The processing circuitry 68 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e g., by network node 16. Processor 70 corresponds to one or more processors 70 for performing network node 16 functions described herein. The memory 72 is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 74 may include instructions that, when executed by the processor 70 and/or processing circuitry 68, causes the processor 70 and/or processing circuitry 68 to perform the processes described herein with respect to network node 16. For example, processing circuitry 68 of the network node 16 may include an STxMP unit 32 which is configured to configure the WD for simultaneous multi-panel transmission, STxMP, according to the maximum rank.

The communication system 10 further includes the WD 22 already referred to. The WD 22 may have hardware 80 that may include a radio interface 82 configured to set up and maintain a wireless connection 64 with a network node 16 serving a coverage area 18 in which the WD 22 is currently located. The radio interface 82 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers.

The hardware 80 of the WD 22 further includes processing circuitry 84. The processing circuitry 84 may include a processor 86 and memory 88. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 84 may comprise integrated circuitry for processing and/or control, e g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 86 may be configured to access (e.g., write to and/or read from) memory 88, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the WD 22 may further comprise software 90, which is stored in, for example, memory 88 at the WD 22, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the WD 22. The software 90 may be executable by the processing circuitry 84. The software 90 may include a client application 92. The client application 92 may be operable to provide a service to a human or non-human user via the WD 22, with the support of the host computer 24. In the host computer 24, an executing host application 50 may communicate with the executing client application 92 via the OTT connection 52 terminating at the WD 22 and the host computer 24. In providing the service to the user, the client application 92 may receive request data from the host application 50 and provide user data in response to the request data. The OTT connection 52 may transfer both the request data and the user data. The client application 92 may interact with the user to generate the user data that it provides.

The processing circuitry 84 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by WD 22. The processor 86 corresponds to one or more processors 86 for performing WD 22 functions described herein. The WD 22 includes memory 88 that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 90 and/or the client application 92 may include instructions that, when executed by the processor 86 and/or processing circuitry 84, causes the processor 86 and/or processing circuitry 84 to perform the processes described herein with respect to WD 22. For example, the processing circuitry 84 of the wireless device 22 may include a panel configuration unit 34 which is configured to configure a number of panels for simultaneous multi-panel transmission, STxMP according to the rank parameter.

In some embodiments, the inner workings of the network node 16, WD 22, and host computer 24 may be as shown in FIG. 8 and independently, the surrounding network topology may be that of FIG. 7.

In FIG. 8, the OTT connection 52 has been drawn abstractly to illustrate the communication between the host computer 24 and the wireless device 22 via the network node 16, without explicit reference to any intermediary devices and the precise routing of messages via these devices. Network infrastructure may determine the routing, which it may be configured to hide from the WD 22 or from the service provider operating the host computer 24, or both. While the OTT connection 52 is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., on the basis of load balancing consideration or reconfiguration of the network).

The wireless connection 64 between the WD 22 and the network node 16 is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to the WD 22 using the OTT connection 52, in which the wireless connection 64 may form the last segment. More precisely, the teachings of some of these embodiments may improve the data rate, latency, and/or power consumption and thereby provide benefits such as reduced user waiting time, relaxed restriction on file size, better responsiveness, extended battery lifetime, etc.

In some embodiments, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 52 between the host computer 24 and WD 22, in response to variations in the measurement results. The measurement procedure and/or the network functionality for reconfiguring the OTT connection 52 may be implemented in the software 48 of the host computer 24 or in the software 90 of the WD 22, or both. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which the OTT connection 52 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software 48, 90 may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 52 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not affect the network node 16, and it may be unknown or imperceptible to the network node 16. Some such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary WD signaling facilitating the host computer’s 24 measurements of throughput, propagation times, latency and the like. In some embodiments, the measurements may be implemented in that the software 48, 90 causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 52 while it monitors propagation times, errors, etc.

Thus, in some embodiments, the host computer 24 includes processing circuitry 42 configured to provide user data and a communication interface 40 that is configured to forward the user data to a cellular network for transmission to the WD 22. In some embodiments, the cellular network also includes the network node 16 with a radio interface 62. In some embodiments, the network node 16 is configured to, and/or the network node’s 16 processing circuitry 68 is configured to perform the functions and/or methods described herein for preparing/initiating/maintaining/ supporting/ending a transmission to the WD 22, and/or preparing/terminating/ maintaining/supporting/ending in receipt of a transmission from the WD 22.

In some embodiments, the host computer 24 includes processing circuitry 42 and a communication interface 40 that is configured to a communication interface 40 configured to receive user data originating from a transmission from a WD 22 to a network node 16. In some embodiments, the WD 22 is configured to, and/or comprises a radio interface 82 and/or processing circuitry 84 configured to perform the functions and/or methods described herein for preparing/initiating/maintaining/ supporting/ending a transmission to the network node 16, and/or preparing/ terminating/maintaining/supporting/ending in receipt of a transmission from the network node 16.

Although FIGS. 7 and 8 show various “units” such as STxMP unit 32, and panel configuration unit 34 as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

FIG. 9 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIGS. 7 and 8, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIG. 8. In a first step of the method, the host computer 24 provides user data (Block SI 00). In an optional substep of the first step, the host computer 24 provides the user data by executing a host application, such as, for example, the host application 50 (Block SI 02). In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (Block S104). In an optional third step, the network node 16 transmits to the WD 22 the user data which was carried in the transmission that the host computer 24 initiated, in accordance with the teachings of the embodiments described throughout this disclosure (Block S106). In an optional fourth step, the WD 22 executes a client application, such as, for example, the client application 92, associated with the host application 50 executed by the host computer 24 (Block SI 08).

FIG. 10 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIG. 7, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 7 and 8. In a first step of the method, the host computer 24 provides user data (Block SI 10). In an optional substep (not shown) the host computer 24 provides the user data by executing a host application, such as, for example, the host application 50. In a second step, the host computer 24 initiates a transmission carrying the user data to the WD 22 (Block SI 12). The transmission may pass via the network node 16, in accordance with the teachings of the embodiments described throughout this disclosure. In an optional third step, the WD 22 receives the user data carried in the transmission (Block SI 14).

FIG. 11 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIG. 7, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 7 and 8. In an optional first step of the method, the WD 22 receives input data provided by the host computer 24 (Block SI 16). In an optional substep of the first step, the WD 22 executes the client application 92, which provides the user data in reaction to the received input data provided by the host computer 24 (Block SI 18). Additionally or alternatively, in an optional second step, the WD 22 provides user data (Block S120). In an optional substep of the second step, the WD provides the user data by executing a client application, such as, for example, client application 92 (Block S122). In providing the user data, the executed client application 92 may further consider user input received from the user. Regardless of the specific manner in which the user data was provided, the WD 22 may initiate, in an optional third substep, transmission of the user data to the host computer 24 (Block SI 24). In a fourth step of the method, the host computer 24 receives the user data transmitted from the WD 22, in accordance with the teachings of the embodiments described throughout this disclosure (Block S126).

FIG. 12 is a flowchart illustrating an example method implemented in a communication system, such as, for example, the communication system of FIG. 7, in accordance with one embodiment. The communication system may include a host computer 24, a network node 16 and a WD 22, which may be those described with reference to FIGS. 7 and 8. In an optional first step of the method, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 16 receives user data from the WD 22 (Block S128). In an optional second step, the network node 16 initiates transmission of the received user data to the host computer 24 (Block S 130). In a third step, the host computer 24 receives the user data carried in the transmission initiated by the network node 16 (Block S132).

FIG. 13 is a flowchart of an example process in a network node 16 for rank restriction for multi-panel uplink (UL) transmission. One or more blocks described herein may be performed by one or more elements of network node 16 such as by one or more of processing circuitry 68 (including the configuration unit 32), processor 70, radio interface 62 and/or communication interface 60. Network node 16 such as via processing circuitry 68 and/or processor 70 and/or radio interface 62 and/or communication interface 60 may be configured to configure the WD 22 with a maximum rank parameter indicating a set of candidate ranks for space division multiplex, SDM, transmission (Block S134). The process also includes configuring the WD 22 for simultaneous multi-panel transmission, STxMP, according to the maximum rank parameter (Block SI 36).

In some embodiments, the method also includes configuring the WD 22 with a first maximum rank parameter for STxMP SDM associated with a first sounding reference signal, SRS, resource set and with a second maximum rank parameter for STxMP SDM associated with a second SRS resource set. In some embodiments, the first maximum rank parameter indicates a first number of panels for physical uplink shared channel, PUSCH, transmission and the second maximum rank parameter indicates a second number of panels for PUSCH transmission. In some embodiments, the method also includes configuring the WD 22 with a minimum rank parameter indicating a minimum number of panels to be used for physical uplink shared channel, PUSCH, transmission. In some embodiments, the process also includes configuring the WD 22 with an exact rank parameter indicating a number of panels to be used for physical uplink shared channel, PUSCH, transmission.

FIG. 14 is a flowchart of an example process in a wireless device 22 according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of wireless device 22 such as by one or more of processing circuitry 84 (including the rank determination unit 34), processor 86, radio interface 82 and/or communication interface 60. Wireless device 22 such as via processing circuitry 84 and/or processor 86 and/or radio interface 82 may be configured to receive a rank parameter indicating a set of candidate ranks for space division multiplex, SDM, transmission (Block S138). The process also includes configuring a number of panels for simultaneous multi-panel transmission, STxMP according to the rank parameter (Block SI 40). In some embodiments, the process also includes: receiving a first maximum rank parameter for STxMP SDM associated with a first sounding reference signal, SRS, resource set and a second maximum rank parameter for STxMP SDM associated with a second SRS resource set; and configuring a first a first number of panels for physical uplink shared channel, PUSCH, transmission according to the first maximum rank parameter and configure a second number of panels for PUSCH transmission according to the second maximum rank parameter. In some embodiments, the rank parameter is a minimum rank parameter indicating a minimum number of panels to be used for physical uplink shared channel, PUSCH, transmission. In some embodiments, the rank parameter is an exact rank parameter indicating a number of panels to be used for physical uplink shared channel, PUSCH, transmission. In some embodiments, a number of panels to be used for physical uplink shared channel, PUSCH, transmission is derived from the rank parameter based on a number of transmission/reception points, TRPs.

FIG. 15 is a flowchart of an example process in a network node 16 for rank restriction for multi-panel uplink (UL) transmission. One or more blocks described herein may be performed by one or more elements of network node 16 such as by one or more of processing circuitry 68 (including the configuration unit 32), processor 70, radio interface 62 and/or communication interface 60. Network node 16 such as via processing circuitry 68 and/or processor 70 and/or radio interface 62 and/or communication interface 60 may be configured to configuring a downlink control information, DCI, message that includes two fields, each field including a rank indicator for one of two sounding reference signal, SRS, resource sets configured for the WD (Block S142). The process includes transmitting the DCI message to the WD (Block S144).

In some embodiments, the two fields are sounding reference signal resource indicator, SRI, fields for non-codebook operation. In some embodiments, the method includes the two fields are transmit precoder matrix indicator, TPMI, fields for codebook operation. In some embodiments, the method includes configuring the WD with a maximum supported rank per SRS resource set of the WD (22), via a single parameter indicating the maximum supported rank applying to both of the two SRS resource sets.

FIG. 16 is a flowchart of an example process in a wireless device 22 according to some embodiments of the present disclosure. One or more blocks described herein may be performed by one or more elements of wireless device 22 such as by one or more of processing circuitry 84 (including the rank determination unit 34), processor 86, radio interface 82 and/or communication interface 60. Wireless device 22 such as via processing circuitry 84 and/or processor 86 and/or radio interface 82 may be configured to receive, from the network node 16, a downlink control information, DCI, message that carries two fields each of which includes a rank indicator for one of two SRS resource sets configured for the WD 22 (Block S146). The method also includes determining a rank for each of the two SRS resource sets of the WD 22 based at least in part on the rank indicator (Block SI 48).

In some embodiments, the two fields are sounding reference signal resource indicator, SRI, fields for non-codebook operation. In some embodiments, the two fields are transmit precoder matrix indicator, TPMI, fields for codebook operation. In some embodiments, determining a rank for each of the two SRS resource sets of the WD 22 is further based at least in part on a maximum supported rank per SRS resource set of the WD 22. In some embodiments, the method includes receiving a single parameter indicating the maximum supported rank per SRS resource set of the WD 22, wherein the single parameter applies to both of the two SRS resource sets. In some embodiments, the single parameter indicates a maximum rank per SRS resource set for SFN STxMP operation. In some embodiments, each SRS resource set is associated with a corresponding panel of the WD which is capable of STxMP operation.

Having described the general process flow of arrangements of the disclosure and having provided examples of hardware and software arrangements for implementing the processes and functions of the disclosure, the sections below provide details and examples of arrangements for rank restriction for multi-panel uplink (UL) transmission.

A first and second “SRS Resource Indicator” field in DCI are utilized, where the number of indicated SRS resources in the second field may be different from the first field

In legacy NR for non-codebook-based multi-TRP PUSCH repetition, a first “SRS Resource Indicator” field + a second “SRS Resource Indicator” field may be used to indicate rank and precoders, where the second “SRS Resource Indicator” field may only indicate the selected precoder, but not the rank (rank for the second “SRS Resource Indicator” field may be the same as the rank indicated by the first “SRS Resource Indicator” field). However, for STxMP, the rank might be different for the two WD 22 panels. Hence, in some embodiments, a new second “SRS Resource Indicator” field may be introduce that may indicate both precoder and rank, where the rank may be the same or different from the rank indicated by the first “SRS Resource Indicator” field.

The length of the first and second first “SRS Resource Indicator” field during STxMP operation may be limited by one or more parameters used to set the maximum supported rank per WD panel (or SRS resource set), as described herein.

A first and second “Preceding Information and Number of Layers” field in DCI

In legacy NR for codebook-based multi-TRP PUSCH repetition, a “Precoding Information and Number of Layers” field + a “Second Precoding Information” field may be used to indicate rank and precoders, where the “Second Precoding Information” field only may indicate the selected precoder, but not the rank (the rank for the “Second Precoding Information” field may be the same as the rank indicated by the “Precoding Information and Number of Layers” field). However, for STxMP, the rank might be different for the two WD panels, hence, In some embodiments, a second “Precoding Information and Number of Layers” field may be introduced that may indicate both precoder and rank, where the rank may be the same or different from the rank indicated by the first “Precoding Information and Number of Layers”.

The length of the first and second “Precoding Information and Number of Layers” field during STxMP operation may be limited by one or more parameters used to set the maximum supported rank per WD panel (or SRS resource set), as described herein.

In some embodiments, the second “Precoding Information and Number of Layers” fields for the STxMP use case may be smaller than legacy “Precoding Information and Number of Layers” field as the max rank will be limited to 2 in NR for STxMP per WD panel.

Configuration of max rank for STxMP transmission

In the following embodiments, it may be assumed that a WD 22 configured for STxMP is configured with two SRS resource sets, and two TPMI/SRI fields, where a first SRS resource set is associated with a first indicated TCI state and a first TPMI/SRI field, and a second SRS resource set is associated with a second indicated TCI state and a second TPMI/SRI field. However, the principles disclosed herein may apply when the WD 22 is configured with more than two SRS resource sets and/or more than two TPMI/SRI fields.

Maximum rank indication for STxMP for codebook based UL transmission

In some embodiments, the maxRank parameter in PUSCH-configure may be reinterpreted when the WD 22 is configured for STxMP operation. This may be done, for example, explicitly with a RRC configured parameter that indicates STxMP operation for the WD 22, or it may be done implicitly, for example in case the WD 22 indicates support for STxMP and the WD 22 has been indicated with two TCI states. When wo SRS resource sets are configured with usage ‘codebook’ and/or ‘nonCodebook’, then the WD 22 assumes STxMP operation.

In some embodiments, the parameter maxRank (in PUSCH-config) may be reinterpreted as the total maximum rank across both SRS resource sets with usage ‘codebook’, when the WD 22 is configured for STxMP operation and indicated with SDM STxMP transmission. So, for example, if the maxRank is set to 3, then the following candidate STxMP ranks for SDM transmission are possible: (1,1), (1,2) and (2,1), but not (2,2), since that has a maximum total rank of 4. In some embodiments, the maximum rank for SFN STxMP transmission and/or 3GPP Rel-17 PUSCH TDM repetition schemes and/or 3GPP Rel-15/16 single TRP schemes may be the same as the maximum rank for SDM STxMP, i.e., the same as indicated by maxRank. In some embodiments, the maximum rank of SFN STxMP transmission and/or 3GPP Rel-17 PUSCH TDM repetition schemes and/or 3GPP Rel-15/16 single TRP schemes may be determined by dividing the value of maxRank with two (either rounded up or rounded down). So, for example, if maxRank is set to 3, the maximum rank for STxMP SFN may be divided by two and rounded down, and hence becomes 1. This would mean that if the WD 22 is indicated with STxMP SFN transmission, the WD 22 may assume that the TPMI/SRI field associated with the first SRS resource set supports maximum rank 1 (and hence use the corresponding “codepoint to rank and precoder” -mapping of that TPMI/SRI field), and the WD 22 may assume that the TPMI/SRI field associated with the second SRS resource set supports maximum rank 1 (and hence use the corresponding “codepoint to rank and precoder” -mapping of that TPMI/SRI field).

In some embodiments, the parameter maxRank may be re-used to also apply for STxMP SDM, such that the maxRank is indicating the maximum rank per SRS resource set. So, for example, if the maxRank is set to 2, then the maximum rank per SRS resource set may be equal to two for STxMP SDM, which gives the following possible STxMP SDM ranks: (1,1), (1,2) and (2,1), (2,2). If the maxRank is set to 1, then the maximum rank per SRS resource set for STxMP SDM may be equal to one, which gives the following possible STxMP ranks: (1,1). In some embodiments, the maxRank may be re-used for STxMP SFN and/or 3GPP Rel-17 PUSCH TDM repetition schemes and/or 3GPP Rel-15/16 single TRP schemes, such that if maxRank is set to 2, then the maximum rank for STxMP SFN and/or 3GPP Rel-17 PUSCH TDM repetition schemes and/or 3GPP Rel-15/16 single TRP schemes is 2. In some embodiments, new parameters are introduced that determine the maximum rank for STxMP operation. In some embodiments, two parameters, maxRankl and maxRank2 are introduced in PUSCH-config, where maxRankl is used to indicate the maximum supported rank for STxMP SDM associated with a first SRS resource set, and maxRank2 is used to indicate the maximum supported rank for STxMP SDM associated with a second SRS resource set. This is illustrated as follows:

- ASN1 START

- TAG-PUSCH-CONFIG- START

PUSCH-Config ::= SEQUENCE { maxRank INTEGER (1..4) maxRankl INTEGER (1,2) maxRank2 INTEGER (1,2)

- TAG-PUSCH-CONFIG- STOP

- ASN1STOP

In some embodiments, the maximum rank for STxMP SFN and/or 3 GPP Rel-17 PUSCH TDM repetition schemes and/or 3GPP Rel-15/16 single TRP schemes may be derived from the legacy parameter “maxRank”. In some embodiments, the maximum rank for STxMP SFN and/or 3GPP Rel-17 PUSCH TDM repetition schemes and/or 3 GPP Rel-15/16 single TRP schemes may be derived from one of the two new parameters maxRankl or maxRank2. For example, the maximum rank may be determined from only maxRankl, or the maximum rank may be determined based on the highest indicated maximum rank from either maxRankl or maxRank2, or the maximum rank may be determined based on the lowest indicated maximum rank from either maxRankl or maxRank2).

In some embodiments, one new parameter is introduced, instead of two, that determines the maximum rank for STxMP transmission. In this case, the parameter maxRank-STxMP may be used to indicate the maximum rank per SRS resource set for SDM STxMP, or the total maximum rank for SDM STxMP across both SRS resource sets. This is illustrated in the following example:

- ASN1 START

- TAG-PUSCH-CONFIG- START

PUSCH-Config ::= SEQUENCE ) maxRank INTEGER (1 .4) maxRank- STxMP INTEGER (1,2) or (1..4)

- TAG-PUSCH-CONFIG- STOP

- ASN1STOP

In a similar way, the parameter may also be used to indicate the maximum rank for STxMP SFN

In some embodiments, additional parameters are introduced that determine the maximum rank for a WD 22 configured for STxMP operation, both for actual STxMP transmission and when dynamically switched to sTRP (e.g., single WD panel) transmission. This is illustrated in the following example:

- ASN1 START

- TAG-PUSCH-CONFIG- START

PUSCH-Config ::= SEQUENCE { maxRank INTEGER (1 4) maxRankl -STxMP INTEGER (1,N) maxRank2-STxMP INTEGER (1,N) maxRankl -sTRP INTEGER (1,N) maxRank2-sTRP INTEGER (1,N)

- TAG-PUSCH-CONFIG- STOP

- ASN1STOP

This may be useful for example, if the maximum rank for STxMP transmission is one layer per SRS resource set, while for single panel transmission, the maximum rank should be two. In this case, the parameter “maxRankl -STxMP” may be used to indicate the maximum supported rank for PUSCH associated with a first SRS resource set during STxMP space division multiplexing (SDM), and the parameter “maxRank2-STxMP” may be used to indicate the maximum supported rank for PUSCH associated with a second SRS resource set during STxMP SDM. In a similar way, the parameter “maxRankl -sTRP” may be used to indicate the maximum supported rank for PUSCH associated with a first SRS resource set during single WD panel transmission, and the parameter “maxRank2- sTRP” may be used to indicate the maximum supported rank for PUSCH associated with a second SRS resource set during single WD panel transmission. The maximum rank supported for STxMP SFN may be determined for example based on one of these four parameters, or be separately configured in another parameter (for example an additional parameter “maxRank- STxMP- SFN” included in PUSCH config).

In some cases, the network node 16 might always want to schedule the WD 22 with a PUSCH rank larger than X. For example, in some mmWave products, rank 2 is always used for PUSCH. In this case, by also indicating a minimum rank, or explicitly indicating exactly which ranks that are available for PUSCH scheduling, the TPMI/SRI overhead in DCI may be reduced. Hence, in some embodiments, a minimum rank and or the exact ranks that may be used for a WD 22 during STxMP (and/or single WD panel transmission) is introduced. One schematic example of this is illustrated in the following example:

- ASN1 START

- TAG-PUSCH-CONFIG- START

PUSCH-Config ::= SEQUENCE { maxRank INTEGER (1 .4) supportedRankl BIT STRING (SIZE (N)) supportedRank2 BIT STRING (SIZE (N))

- TAG-PUSCH-CONFIG- STOP

- ASN1STOP where a bitmap is used to indicate the available ranks for a WDs PUSCH transmission. In this example, two parameters are introduced “supportedRankl” and “supportedRank2”, where “supportedRankl” may be used to indicate the supported rank for a first SRS resource set and “supportedRank2” may be used to indicate the supported ranks for a second SRS resource set (not that more than two ranks may be indicated in case the WD 22 supports STxMP from more than two WD panels). For example, if the bit string of “supportedRankl” indicates [1,1], both rank 1 and rank 2 may be supported for the first SRS resource set, while if “supportedRank2” indicates [0,1], only rank 2 may be supported for the second SRS resource set. In some embodiments, a single parameter (e.g., “supportedRank”) may be used instead of two parameters, where the single parameter indicates the available PUSCH ranks for both SRS resource sets (i.e., if the parameter “supportedRank” is set to [1,1], then rank 1 and rank 2 may be supported for both a first and a second SRS resource set).

Maximum rank indication for STxMP for non-codebook based UL transmission

In some embodiments, the “maxMIMO-Layers” parameter in PUSCH- ServingCellConfigure may be re-interpreted when the WD 22 is configured for STxMP (which, for example, may be done explicitly with a RRC configured parameter that indicates STxMP operation for the WD 22 (e.g., for a serving cell), or it may be done implicitly, for example in case the WD 22 indicates support for STxMP and the WD 22 has been indicated with two TCI states and two SRS resource sets with usage ‘codebook’ and/or ‘nonCodebook’).

In some embodiments, the “maxMIMO-Layers” may be re-interpreted as the total maximum rank across both SRS resource sets with usage ‘nonCodebook’ when the WD 22 is configured for STxMP and indicated with SDM UL transmission. So, for example, if the “maxMIMO-Layers” is set to 3, then the following candidate STxMP ranks for SDM transmission are possible: (1,1), (1,2) and (2,1), but not (2,2), since that has a maximum total rank of 4. In one related embodiment, the maximum rank for SFN STxMP transmission and/or 3GPP Rel-17 PUSCH TDM repetition schemes and/or 3 GPP Rel-15/16 single TRP schemes may be the same as the maximum rank for SDM STxMP. In another related embodiment the maximum rank of SFN STxMP transmission and/or 3GPP Rel-17 PUSCH TDM repetition schemes and/or 3GPP Rel-15/16 single TRP schemes may be determined by dividing the value of “maxMIMO-Layers” with two (either rounded up or rounded down).

In some embodiments, the “maxMIMO-Layers” may be re-used for STxMP SDM, such that the “maxMIMO-Layers” indicates the maximum rank per SRS resource set. So, for example, if the “maxMIMO-Layers” is set to 2, then the maximum rank per SRS resource set may be equal to two for STxMP SDM, which gives the following possible STxMP SDM ranks: (1,1), (1,2) and (2,1), (2,2), and if the “maxMIMO-Layers” is set to 1, then the maximum rank per SRS resource set for STxMP SDM may be equal to one, which gives the following possible STxMP ranks: (1,1). In some embodiments, the “maxMIMO-Layers” may be re-used for STxMP SFN and/or 3GPP Rel-17 PUSCH TDM repetition schemes and/or 3 GPP Rel-15/16 single TRP schemes, such that if “maxMIMO-Layers” is set to 2, then the maximum rank for STxMP SFN and/or 3GPP Rel-17 PUSCH TDM repetition schemes and/or 3GPP Rel-15/16 single TRP schemes is 2.

In some embodiments, parameters are introduced that determine the maximum rank for STxMP transmission. For example:

- ASN1 START

- TAG-PUSCH- SERVINGCELLCONFIG- START

PUSCH-ServingCellConfig ::= SEQUENCE {

... [[ maxMIMO-Layers INTEGER (1 .4) maxMIMO-Lay ers 1 INTEGER (1,2) maxMIMO-Layers2 INTEGER (1,2)

...]]

- TAG-PUSCH- SERVINGCELLCONFIG- STOP

- ASN1STOP

Two parameters, maxMIMO-Layers 1 and maxMIMO-Lay ers2 may be introduced in PUSCH-config, where maxMIMO-Layers 1 may be used to indicate the maximum supported rank for STxMP SDM associated with a first SRS resource set, and maxMIMO- Layers2 may be used to indicate the maximum supported rank for STxMP SDM associated with a second SRS resource set. In some embodiments, the maximum rank for STxMP SFN and/or 3GPP Rel-17 PUSCH TDM repetition schemes and/or 3GPP Rel- 15/16 single TRP schemes may be derived from the legacy parameter “maxMIMO- Layers”. In some embodiments, the maximum rank for STxMP SFN and/or 3GPP Rel-17 PUSCH TDM repetition schemes and/or 3GPP Rel-15/16 single TRP schemes may be derived from one of the two new parameters maxMIMO-Layers 1 or maxMIMO-Lay ers2. For example the maximum rank may be determined from only maxMIMO-Layers 1, or the max rank may be determined based on the highest indicated max rank from maxMIMO-Layers 1 and maxMIMO-Layers2, or the max rank may be determined based on the lowest indicated max rank from maxMIMO-Layers 1 and maxMIMO-Lay ers2.

In some embodiments, one new parameter is introduced, instead of two, that determines the maximum rank for STxMP transmission, as schematically illustrated in the following example:

- ASN1 START

- TAG-PUSCH- SERVINGCELLCONFIG- START

PUSCH-ServingCellConfig ::= SEQUENCE { ... [[ maxMIMO-Layers INTEGER (1 .4) maxMIMO-Layers-STxMP INTEGER (1,2) or (1..4)

...]]

- TAG-PUSCH- SERVINGCELLCONFIG- STOP

- ASN1STOP

In this case, the parameter maxMIMO-Layers -STxMP may be used to indicate the maximum rank per SRS resource set for SDM STxMP, or the total maximum rank for SDM STxMP across both SRS resource sets. In a similar way, the parameter may also be used to indicate the maximum rank for STxMP SFN.

In some embodiments, additional parameters may be introduced, as schematically illustrated in the following example:

- ASN1 START

- TAG-PUSCH- SERVINGCELLCONFIG- START

PUSCH-ServingCellConfig ::= SEQUENCE {

... [[ maxMIMO-Layers INTEGER (1 .4) maxMIMO-Lay ers 1 - STxMP INTEGER (1,N) maxMIMO-Layers2-STxMP INTEGER (1,N) maxMIMO-Layers 1 -sTRP INTEGER (1,N) maxMIMO-Layers2-sTRP INTEGER (1,N) ...]]

— TAG-PUSCH-SERVINGCELLCONFIG-STOP

- ASN1STOP

Some parameters determine the maximum rank for a WD 22 configured for STxMP operation, both for actual STxMP transmission and when dynamically switched to sTRP (e g., single WD panel) transmission. This may be useful for example, if the maximum rank for STxMP transmission is one layer per SRS resource set, while for single panel transmission, the maximum rank should be two. In this case, the parameter “maxMIMO-Layersl-STxMP” may be used to indicate the maximum supported rank for PUSCH associated with a first SRS resource set during STxMP SDM, and the parameter “maxMIM0-Layers2-STxMP” may be used to indicate the maximum supported rank for PUSCH associated with a second SRS resource set during STxMP SDM. In a similar way, the parameter “maxMIMO-Layersl-sTRP” may be used to indicate the maximum supported rank for PUSCH associated with a first SRS resource set during single WD panel transmission, and the parameter “maxMIMO-Layers2-sTRP” may be used to indicate the maximum supported rank for PUSCH associated with a second SRS resource set during single WD panel transmission. The maximum rank supported for STxMP SFN may be determined for example based on one of these four parameters, or be separately configured in another parameter (for example an additional parameter “maxMIMO- Layers-STxMP-SFN” included in PUSCH config).

In some cases, the network, such as via the network node 16, might always want to schedule the WD 22 with a PUSCH rank larger than X. For example, in some mmWave products, rank 2 is always used for PUSCH. In this case, by also indicating a minimum rank, or explicitly indicating exactly which ranks that are available for PUSCH scheduling, the TPMI/SRI overhead in DCI may be reduced. Hence, in some embodiments, a minimum rank and or the exact ranks that may be used for a WD 22 during STxMP (and/or single WD panel transmission) is introduced. One schematic example of this is illustrated in the following example:

- ASN1 START

- TAG-PUSCH- SERVINGCELLCONFIG- START

PUSCH-ServingCellConfig ::= SEQUENCE {

... [[ maxMIMO-Layers INTEGER ( 1..4) supportedMIMO-Layers 1 BIT STRING (SIZE (2)), supportedMIMO-Layers2 BIT STRING (SIZE (2)),

...]]

- TAG-PUSCH- SERVINGCELLCONFIG- STOP

- ASN1STOP where a bitmap is used to indicate the available ranks for a WDs PUSCH transmission. In this example, two parameters are introduced “ supportedMIMO-Layers 1” and “supportedMIMO-Layers2”, where “ supportedMIMO-Layers 1” may be used to indicate the supported rank for a first SRS resource set and “supportedMIMO-Layers2” may be used to indicate the supported ranks for a second SRS resource set. For example, if the bit string of “supportedMIMO-Layersl” indicates [1,1], both rank 1 and rank 2 may be supported for the first SRS resource set, while if “supportedMIMO-Layers2” indicates [0,1], only rank 2 may be supported for the second SRS resource set. In some embodiments, a single parameter (e.g., “supportedMIMO-Layers”) may be used instead of two parameters, where the single parameter indicates the available PUSCH ranks for both SRS resource sets (i.e., if the parameter “supportedMIMO-Layers” may be set to [1,1], then rank 1 and rank 2 may be supported for both a first and a second SRS resource set).

In some embodiments, the WD 22 signals in WD capability signaling that it supports to be configured with minimum rank and/or available ranks for single-panel and/or multi-panel UL data transmission.

Extension to future cellular networks

In the embodiments described above, reference is made to SRS However, a UL sounding reference signal is intended, which might be called something else in 6G. The disclosure also uses the words SRI, which is used to indicate an SRS resource However, an indication of an UL sounding reference signal is intended, which might be called something else in 6G. Also, the term TPMI is used to indicate rank and precoder for UL transmission. However, in 6G, the rank and precoder indication might be performed in another way and be called something else, but there is a limit the number of bits used for indicating rank and precoder for UL data transmission by restricting the available ranks. In the examples above, reference is made to PUSCH. However, this might be called something else in 6G, and here UL data transmission is referenced. In addition, the rank restriction parameter (maxRank and maxMIMO-Layers) might be called something else in 6G and they might be located in other RRC configure information elements than PUSCH-configure and PUSCH-ServingCellConfig Extension to URLLC/eMBB/XR applications

In NR, support for dedicated ultra-reliable and low latency communications (URLLC) features have been introduced to support high reliable low latency communication. One part of introducing these schemes was to introduce a smaller (in overhead) DCI format for UL data transmission scheduling, i.e., DCI format 0 2, which may be able to schedule URLLC data transmission while using fewer bits in DCI (and hence, utilizing stronger coding which results in higher reliability). Since some schemes related to UL multi-panel transmission target reliability (for example STxMP SFN, 3 GPP Rel-17 multi-TRP PUSCH repetition schemes) and some target evolved mobile broadband (eMBB) (i.e., increase data rate), it may be beneficial to use different rank restrictions for eMBB communication and URLLC communication. Hence, in some embodiments, separate maximum rank restrictions for UL data transmission over multiple WD panels are configured for different types of data communications (and/or for different DCI formats). For example, this disclosure is extended such that all the embodiments described above may be configured per type of data communication (e.g., eMBB, XR, URLLC)

Some embodiments may include one or more of the following:

Embodiment Al . A network node configured to communicate with a wireless device (WD), the network node configured to, and/or comprising a radio interface and/or comprising processing circuitry configured to: configure the WD with a maximum rank parameter indicating a set of candidate ranks for space division multiplex, SDM, transmission; and configure the WD for simultaneous multi-panel transmission, STxMP, according to the maximum rank parameter.

Embodiment A2. The network node of Embodiment Al, the network node, radio interface and/or processing circuitry are further configured to configure the WD with a first maximum rank parameter for STxMP SDM associated with a first sounding reference signal, SRS, resource set and with a second maximum rank parameter for STxMP SDM associated with a second SRS resource set.

Embodiment A3. The network node of any of Embodiments Al and A2, wherein the first maximum rank parameter indicates a first number of panels for physical uplink shared channel, PUSCH, transmission and the second maximum rank parameter indicates a second number of panels for PUSCH transmission.

Embodiment A4. The network node of any of Embodiments A1-A3, wherein the network node, radio interface and/or processing circuitry are further configured to configured the WD with a minimum rank parameter indicating a minimum number of panels to be used for physical uplink shared channel, PUSCH, transmission.

Embodiment A5. The network node of any of Embodiments A1-A4, wherein the network node, radio interface and/or processing circuitry are further configured to configured the WD with an exact rank parameter indicating a number of panels to be used for physical uplink shared channel, PUSCH, transmission.

Embodiment Bl. A method implemented in a network node configured to communicate with a wireless device, WD, the method comprising: configuring the WD with a maximum rank parameter indicating a set of candidate ranks for space division multiplex, SDM, transmission; and configuring the WD for simultaneous multi-panel transmission, STxMP, according to the maximum rank parameter.

Embodiment B2. The method of Embodiment B 1 , further comprising configuring the WD with a first maximum rank parameter for STxMP SDM associated with a first sounding reference signal, SRS, resource set and with a second maximum rank parameter for STxMP SDM associated with a second SRS resource set.

Embodiment B3. The method of any of Embodiments Bl and B2, wherein the first maximum rank parameter indicates a first number of panels for physical uplink shared channel, PUSCH, transmission and the second maximum rank parameter indicates a second number of panels for PUSCH transmission.

Embodiment B4. The method of any of Embodiments B1-B3, further comprising configuring the WD with a minimum rank parameter indicating a minimum number of panels to be used for physical uplink shared channel, PUSCH, transmission.

Embodiment B5. The method of any of Embodiments B1-B4, further comprising configuring the WD with an exact rank parameter indicating a number of panels to be used for physical uplink shared channel, PUSCH, transmission.

Embodiment Cl . A wireless device (WD) configured to communicate with a network node, the WD configured to, and/or comprising a radio interface and/or processing circuitry configured to: receive a rank parameter indicating a set of candidate ranks for space division multiplex, SDM, transmission; and configure a number of panels for simultaneous multi-panel transmission, STxMP according to the rank parameter.

Embodiment C2. The WD of Embodiment Cl, wherein the WD, radio interface and/or processing circuitry are further configured to: receive a first maximum rank parameter for STxMP SDM associated with a first sounding reference signal, SRS, resource set and a second maximum rank parameter for STxMP SDM associated with a second SRS resource set; and configure a first a first number of panels for physical uplink shared channel, PUSCH, transmission according to the first maximum rank parameter and configure a second number of panels for PUSCH transmission according to the second maximum rank parameter.

Embodiment C3. The WD of Embodiment Cl, wherein the rank parameter is a minimum rank parameter indicating a minimum number of panels to be used for physical uplink shared channel, PUSCH, transmission. Embodiment C4. The WD of Embodiment Cl, wherein the rank parameter is an exact rank parameter indicating a number of panels to be used for physical uplink shared channel, PUSCH, transmission.

Embodiment C5. The WD of Embodiments Cl, wherein a number of panels to be used for physical uplink shared channel, PUSCH, transmission is derived from the rank parameter based at least in part on a number of transmission/reception points, TRPs.

Embodiment DI . A method implemented in a wireless device (WD) configured to communicate with a network node, the method comprising: receiving a rank parameter indicating a set of candidate ranks for space division multiplex, SDM, transmission; and configuring a number of panels for simultaneous multi-panel transmission, STxMP according to the rank parameter.

Embodiment D2. The method of Embodiment D 1 , further comprising: receiving a first maximum rank parameter for STxMP SDM associated with a first sounding reference signal, SRS, resource set and a second maximum rank parameter for STxMP SDM associated with a second SRS resource set; and configuring a first a first number of panels for physical uplink shared channel, PUSCH, transmission according to the first maximum rank parameter and configure a second number of panels for PUSCH transmission according to the second maximum rank parameter.

Embodiment D3. The method of Embodiment D 1 , wherein the rank parameter is a minimum rank parameter indicating a minimum number of panels to be used for physical uplink shared channel, PUSCH, transmission.

Embodiment D4. The method of Embodiment D 1 , wherein the rank parameter is an exact rank parameter indicating a number of panels to be used for physical uplink shared channel, PUSCH, transmission.

Embodiment D5. The method of Embodiments D 1 , wherein a number of panels to be used for physical uplink shared channel, PUSCH, transmission is derived from the rank parameter based at least in part on a number of transmission/reception points, TRPs.

As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and/or computer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Any process, step, action and/or functionality described herein may be performed by, and/or associated to, a corresponding module, which may be implemented in software and/or firmware and/or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that may be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

Some embodiments are described herein with reference to flowchart illustrations and/or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, may be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable memory or storage medium that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

It is to be understood that the functions/acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Python, Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments may be combined in any way and/or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.

It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.

Claims

1. A wireless device, WD (22), configured to communicate with a network node (16), the WD (22) configured to: receive from the network node (16) a downlink control information, DCI, message that includes two fields, each field including a rank indicator for one of two sounding reference signal, SRS, resource sets configured for the WD (22); and determine a rank for each of the two SRS resource sets of the WD (22) based at least in part on the rank indicator.

2. The WD (22) of Claim 1, wherein the two fields are SRS resource indicator, SRI, fields for non-codebook operation.

3. The WD (22) of Claim 1, wherein the two fields are transmit precoder matrix indicator, TPMI, fields for codebook operation.

4. The WD (22) of any of Claims 1-3, wherein determining a rank for each of the two SRS resource sets of the WD (22) is further based at least in part on a maximum supported rank per SRS resource set of the WD (22).

5. The WD (22) of Claim 4, wherein the WD (22) is configured to receive a single parameter indicating the maximum supported rank per SRS resource set of the WD (22), wherein the single parameter applies to both of the two SRS resource sets.

6. The WD (22) of Claim 5, wherein the single parameter indicates a maximum rank per SRS resource set for single frequency network, SFN, Simultaneous multi-panel transmission, STxMP, operation.

7. The WD (22) of any of Claims 1-6, wherein each SRS resource set is associated with a corresponding panel of the WD which is capable of STxMP operation.

8. The WD (22) of any of Claims 1-7, wherein a first SRS resource set is associated with a first transmission configuration indicator, TCI, state and a first transmission precoder matrix indicator/SRS resource indicator, TPMI/SRI field and a second SRS resource set is associated with a second TCI state and a second TPMI/SRI field.

9. A method in a wireless device, WD (22), configured to communicate with a network node (16), the method comprising: receiving (SI 46) from the network node (16) a downlink control information, DCI, message that includes two fields, each field including a rank indicator for one of two sounding reference signal, SRS, resource sets configured for the WD (22); and determining (S148) a rank for each of the two SRS resource sets of the WD (22) based at least in part on the rank indicator.

10. The method of Claim 9, wherein the two fields are sounding reference signal resource indicator, SRI, fields for non-codebook operation.

11. The method of Claim 10, wherein the two fields are transmit precoder matrix indicator, TPMI, fields for codebook operation.

12. The method of any of Claims 9-11, wherein determining a rank for each of the two SRS resource sets of the WD (22) is further based at least in part on a maximum supported rank per SRS resource set of the WD (22).

13. The method of Claim 12, further comprising receiving a single parameter indicating the maximum supported rank per SRS resource set of the WD (22), wherein the single parameter applies to both of the two SRS resource sets.

14. The method of Claim 13, wherein the single parameter indicates a maximum rank per SRS resource set for SFN STxMP operation.

15. The method of any of Claims 9-14, wherein each SRS resource set is associated with a corresponding panel of the WD being capable of STxMP operation.

16. A network node (16) configured to communicate with a wireless device, WD (22), the network node (16) configured to: configure a downlink control information, DCI, message that includes two fields, each field including a rank indicator for one of two sounding reference signal, SRS, resource sets configured for the WD (22); and transmit the DCI message to the WD (22).

17. The network node (16) of Claim 16, wherein the two fields are sounding reference signal resource indicator, SRI, fields for non-codebook operation.

18. The network node (16) of Claim 16, wherein the two fields are transmit precoder matrix indicator, TPMI, fields for codebook operation.

19. The network node (16) of any of Claims 16-18, further being configured to: configure the WD with a maximum supported rank per SRS resource set of the WD (22), via a single parameter indicating the maximum supported rank applying to both of the two SRS resource sets.

20. The network node (16) of Claim 19, wherein the single parameter indicates maximum rank per SRS resource set for SFN STxMP operation or SDM STxMP operation.

21. A method in a network node (16) configured to communicate with a wireless device, WD (22), the method comprising: configuring (SI 42) a downlink control information, DCI, message that includes two fields, each field including a rank indicator for one of two sounding reference signal, SRS, resource sets configured for the WD (22); and transmitting (S144) the DCI message to the WD (22).

22. The method of Claim 21, wherein the two fields are sounding reference signal resource indicator, SRI, fields for non-codebook operation.

23. The method of Claim 21, wherein the two fields are transmit precoder matrix indicator, TPMI, fields for codebook operation.

24. The method of any of claims 21 to 23, further comprising: configuring the WD with a maximum supported rank per SRS resource set of the WD (22), via a single parameter indicating the maximum supported rank applying to both of the two SRS resource sets.