CN112335316A

CN112335316A - Resource sharing for uplink transmissions

Info

Publication number: CN112335316A
Application number: CN201980042750.6A
Authority: CN
Inventors: 乌莫·萨利姆
Original assignee: Jiekai Communications Shenzhen Co Ltd
Current assignee: Jiekai Communications Shenzhen Co Ltd
Priority date: 2018-08-02
Filing date: 2019-08-01
Publication date: 2021-02-05
Anticipated expiration: 2039-08-01
Also published as: GB201812600D0; GB2576034B; WO2020025032A1; GB2576034A; CN112335316B

Abstract

A method for providing resource utilization information to a UE to assist in Listen Before Talk (LBT) procedures. The base station sends to the UE an indication of resources allocated to other UEs associated with the same base station. When the UE performs the LBT procedure, it compares the sensed utilization rate with the utilization rate indicated by the base station to confirm whether the UE is allowed to transmit.

Description

Resource sharing for uplink transmissions

Technical Field

The following disclosure relates to sharing transmission resources in a cellular wireless network, and more particularly to sharing of uplink transmission resources in an unlicensed spectrum.

Background

Wireless communication systems, such as third generation (3G) mobile telephone standards and technologies, are well known. Such 3G standards and techniques have been developed by the third generation partnership project (3 GPP). Third generation wireless communications have been widely developed to support macrocell mobile telephone communications. Communication systems and networks have evolved towards broadband and mobile systems.

In a cellular wireless communication system, User Equipment (UE) is connected to a Radio Access Network (RAN) over a wireless link. The RAN includes: a set of base stations providing radio links to UEs located in cells covered by the base stations; and interfaces to the Core Network (CN) that provides overall network control). It is to be understood that the RAN and CN each perform corresponding functions related to the overall network. For convenience, the term "cellular network" will be used to refer to the combined RAN and CN, and it will be understood that this term is used to refer to the various systems for performing the disclosed functions.

The third generation partnership project has developed a so-called Long Term Evolution (LTE) system, evolved universal mobile telecommunications system geographical radio access network (E-UTRAN), for a mobile access network in which one or more macro cells are supported by base stations called enodebs or enbs (evolved nodebs). Recently, LTE is being further developed towards so-called 5G or NR (new radio) systems, in which one or more cells are supported by base stations called gnbs. NR is proposed to use an Orthogonal Frequency Division Multiplexing (OFDM) physical transmission format.

The NR protocol is intended to provide options for operation in an unlicensed radio band (which will be referred to as NR-U). When operating in the unlicensed radio band, the gNB and the UE must compete for physical medium access rights with other devices. For example, Wi-F, NR-U and LAA may use the same physical media resource.

To share resources, a listen-before-talk (LBT) protocol is proposed in which the gNB or UE monitors the available resources and starts transmission only if there is no conflict with another device already using the resources. Once the LBT procedure is successful ("wins" the resource), the gNB or UE will gain access to the resource until the Channel Occupancy Time (COT) provided that the interruption of the transmission does not exceed a predefined time interval (e.g., 16 μ s).

There are two types of LBT procedures that have been standardized for LAA and have been proposed for UL transmission in NR. In type 1, a series of time slots must be detected on a channel to indicate that a channel assessment (CCA) is cleared and that the channel is available. The number of slots that need to be sensed is defined by the Contention Window Size (CWS) selected by the UE according to factors including the priority class of the UE. In type 2, a single short period is used to perform CCA, the duration of which has been fixed to 25 microseconds in 3 GPP.

Transmissions in an unlicensed spectrum must comply with various current regulations regarding that spectrum. For example, many regulations specify Occupied Channel Bandwidth (OCB) and Nominal Channel Bandwidth (NCB) that must be adhered to. NCB defines the widest frequency band allocated to the channel, including the guard band, while OCB defines the bandwidth containing a defined portion (typically 99%) of the signal power. Typically, the OCB must be between 80% and 100% of the NCB. For example, ETSI EN 301.893 defines the european union's requirements for the 5GHz band.

It is proposed to use interlace-based resource allocation for UL transmission. This allows each UE to span a wider bandwidth and transmit a higher total power without occupying the entire bandwidth. Fig. 1 shows an interlaced structure with ten interlaced lines. Data is transmitted on frequency multiplexed interlaced resource blocks. The basic resource allocation unit is considered as one interlace, which is set to meet the OCB requirement discussed above, allowing multiplexing of multiple UEs on different interlaces.

The interlaced structure also allows energy spreading to meet PSD requirements and still has sufficient energy transfer to ensure that the signal can be decoded at the receiver. In the example interlaced structure from LTE eLAA, the interlaced structure includes 10 RBs/interlaces for both 10MHz and 20MHz system bandwidths. RBs in interlaced scanning are equidistant and demodulation reference symbols (DMRS) in the unlicensed spectrum use inherited generation sequences and symbol positions while maintaining the same frequency position as PUSCH REs in the middle symbol of each slot.

NR can be used for both slot-based and non-slot-based scheduling. In a slot-based system, a control message (PDCCH) is transmitted in the first 2 or 3 symbols of each slot and resources are scheduled for the slot; while in non-slot based scheduling, the PDCCH may be transmitted at different periods during the slot. These arrangements can make efficient use of resources and be tailored to the requirements of each UE.

To initiate transmission of UL data on the Physical Uplink Shared Channel (PUSCH), the eNB indicates to the UE the type of channel access procedure it should use in the uplink grant scheduling message. In general, the uplink channel access procedure of type 1 is used to initialize the MCOT containing PUSCH transmission, while the uplink channel access procedure of type 2 is used inside the MCOT to resume suspended transmission or to change the transmission direction from downlink to uplink. In order to transmit a Sounding Reference Signal (SRS) without PUSCH from a UE, the UE always utilizes the uplink channel access procedure of type 1 with the highest priority class.

LBT procedures of

types

1 and 2 run successfully where devices are only allowed to start transmitting at a single symbol, but different devices are not allowed to start transmitting at different symbols in an efficient manner. Fig. 2 shows the assignment of two UEs (UE1 and UE2) to interlace 0 and 2. The figure shows the interlaces as scheduling entities, even though in practice each single interlace may comprise a plurality of distributed resource blocks. For the UE1, a conventional LBT may identify channel availability and start transmission at a scheduled time. In addition, after the UE1 has started transmission, the UE2 is scheduled to start transmission halfway through the slot. Since UE1 and UE2 are associated with the same gNB, it can theoretically start transmitting even though UE1 is already transmitting. However, when performing its LBT procedure, the UE2 will detect the transmit power of the UE1, so even though the UE2 has been scheduled to use different interlaces, transmission cannot begin because the medium is already occupied by the UE 1.

Fig. 3 shows the same resource allocation, but here the relevant gNB has lost access to the transmission medium and the UE1 has not started transmission at the beginning of the time slot. The Wi-Fi device takes access and begins transmitting on the bandwidth allocated to UE1 and UE 2. The gNB may have lost access due to the Wi-Fi device seizing the channel during the switching time between DL and UL, the Wi-Fi device may have seized the channel during the LBT interval of the UE1, or the UE1 may have missed its UL grant and therefore did not start transmitting.

In both fig. 2 and fig. 3, UE2 will detect the transmission power, so even though it has the right to do so in fig. 2, it cannot start transmission if both UE1 and UE2 are scheduled by the same gNB. Even though the UE2 may recognize that the power detected during LBT is a transmission on a particular interlace and has no conflict with its assigned interlace, it still cannot transmit because it is not known whether the relevant device is part of the same group as the UE2 and therefore whether the transmission is allowed to start.

Therefore, there is a need for an LBT procedure that allows for efficient multiplexing of devices.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

There is provided a method of resource sharing in a cellular communication system, the method being performed by a base station and comprising the steps of: sending an indication from a base station to a UE indicating resources available for Uplink (UL) transmissions from the UE to the base station; transmitting, from the base station to the UE, an indication of UL transmission resources allocated to other UEs associated with the base station during a time period prior to a start of resources indicated as available to the UE for UL transmissions.

There is also provided another method of resource sharing in a cellular communication system, the method being performed by a UE and comprising the steps of: receiving an indication from a base station indicating resources available for Uplink (UL) transmissions from the UE to the base station; receiving, from the base station, an indication of UL transmission resources allocated to other UEs associated with the base station during a time period prior to a start of resources indicated as available to the UEs for UL transmissions.

The resources may be in an unlicensed band.

The resource may comprise a plurality of interlaced lines.

The indication regarding UL transmission resources allocated to other UEs may include a bitmap field.

Each bit of the bitmap may correspond to a set of physical resources.

The groups of physical resources may be interlaced.

The indication of UL transmission resources allocated to other UEs may be sent in a DCI message common to the groups.

The DCI message common to the group may be a DCI message of DCI1-C format.

The indication of UL transmission resources allocated to other UEs may be sent in a UE-specific DCI message.

The UE-specific DCI message may be a DCI message further comprising an indication of resources available for transmission from the UE to the base station.

The indication of resources available for transmission from the UE to the base station may comprise an indication of a subsequent message indicating UL transmission resources allocated to other UEs.

The UL transmission resources allocated to the other UEs may include resources allocated for transmission based on the configured grant.

The UL transmission resources allocated to other UEs may include resources allocated to UEs associated with the base station but operating in different beams than the UEs.

The resource indication may be a resource occupancy for a symbol preceding a first symbol of a resource to which the UE is allocated.

The indication of UL transmission resources allocated to other UEs may comprise utilization in a plurality of different times.

The time period may be a Listen Before Talk (LBT) time period of the UE.

The indication of UL transmission resources allocated to other UEs may be received in a DCI message common to a group.

The DCI message common to the group may be a DCI message of DCI1-C format.

The indication of UL transmission resources allocated to other UEs may be received in a UE-specific DCI message.

The method may further comprise: performing an LBT procedure to identify utilized resources in an LBT period, wherein the UL is transmitted only in its allocated UL transmission resources if the utilized resources are the same as resources indicated as allocated to other UEs.

The method may further include the step of performing an LBT procedure to identify utilized resources in an LBT period, wherein the UL is transmitted only in its allocated UL transmission resources if the utilized resources are the same as or a subset of resources indicated as allocated to other UEs.

The method may further include the step of performing an LBT procedure to identify utilized resources in an LBT period, wherein the UL is transmitted only in its allocated UL transmission resources if the utilized resources differ from resources indicated as allocated to other UEs by less than a predetermined threshold.

A UE and a base station are provided for performing the related method.

The non-transitory computer readable medium may include at least one of the group consisting of: hard disk, CD-ROM, optical storage device, magnetic storage device, read-only memory, programmable read-only memory, erasable programmable read-only memory, EPROM, electrically controlled erasable programmable read-only memory, and flash memory.

Drawings

Further details, aspects and embodiments of the invention will be described below, by way of example only, with reference to the accompanying drawings. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. Like reference numerals have been included in the various drawings to facilitate understanding.

Fig. 1 shows a set of interlaces.

Fig. 2 shows the scheduling of two UEs on different interlace.

Fig. 3 shows an example of a contention transmitter occupying a transmission medium.

Fig. 4 shows the LBT procedure.

Fig. 5 to 8 show UE scheduling on resources.

Detailed Description

Those skilled in the art will recognize and appreciate that the specifics of the described examples are merely illustrative of some embodiments and that the teachings set forth herein are applicable in a variety of alternative settings.

The following disclosure provides an improved LBT mechanism that attempts to achieve more efficient multiplexing of UE UL transmissions. Regulations on unlicensed spectrum specify that only one device or group of devices is allowed to access the spectrum at a time. A cell of a cellular system and all UEs associated with the cell are defined as a group. In the scenario shown in fig. 2 above, UE1 and UE2 are associated with the same cell, thus allowing UE2 to start transmitting even though UE1 is already transmitting in the spectrum.

In an enhanced LBT procedure, described in more detail below, the base station informs the UE of the spectrum allocation of other UEs in the same cell. The UEs themselves are configured such that when performing the LBT procedure, they can identify which frequency resources are being used. Thus, the UE may associate the base station's spectrum utilization indication with measurement data to determine whether the power detected in the LBT procedure is from other UEs of the same cell. If the detected power is related to a UE scheduled by the same cell, then the UE is free to transmit as scheduled because it is part of the same group, in the example of fig. 2, the UE2 will receive an indication that the UE is scheduled on interlace 0. When performing LBT, the UE2 will recognize that power is being transmitted on this interlace and can confirm that it is transmitting freely. However, in the example of fig. 3, the power and resource occupancy detected by the UE2 will not match the indication from the base station, and the UE will not transmit.

Fig. 4 shows a flow chart of an enhanced LBT procedure. In step 400, the base station transmits a scheduling message to the UE indicating DL and/or UL scheduling for a time slot. In step 401 (which may be performed before step 400, in conjunction with step 400, or after step 400), the base station sends an indication of the resources allocated to other UEs in the relevant time slot.

In step 402, the UE performs an LBT procedure before starting UL transmission as indicated by the scheduling message. In step 403, the UE compares the spectrum utilization identified in step 402 with the resource indication received in step 401. If the indicated resources are related to the utilized spectrum (e.g., as described below), the UE transmits as scheduled in step 404. Conversely, if the indicated resources are not associated with the utilized spectrum (e.g., as described below), the UE may not transmit 405 as scheduled because it appears that another device is already occupying the spectrum.

The resource indication may be made on the basis of a Physical Resource Block (PRB) group, where the size of the group may be adjusted. For example, as previously mentioned, an interlace-based transmission scheme such as Rel-14eLAA has been adapted for UL transmission designs, where each interlace consists of an inserted set of PRBs. Thus, interlace is a basic unit of resource allocation, and one or more interlaces may be allocated to each UE. For example only, Rel-14eLAA defines 10 RBs/interlaces for the UL, providing 5 and 10 interlaces for the 10MHz and 20MHz spectra, respectively.

Thus, the resource indication should indicate to the UE which interlace is occupied by other UEs associated with the same cell. Such an indication may be provided using a bitmap, where each bit represents the occupancy or allocation status of the corresponding interlace (or other suitable resource block). The bitmap is an efficient method of encoding required information, and thus signaling overhead can be reduced. If the relevant protocol uses different interlaced designs or different groupings of PRBs that can be allocated to users for UL transmission, the resource occupancy bitmap should correspond to the grouping of PRBs used for resource allocation.

Fig. 5 shows an example in which two UEs, UE0 and UE1, are scheduled on different interlaces at different times in a slot. In this example, 5 interlaces are available. In fig. 5(a), UE0 is scheduled to transmit two transport blocks in two slots (slot #1 and slot #2), while UE1 is scheduled to transmit one transport block in slot 2. In fig. 5(b), the UE0 is scheduled to transmit one transport block on both slot #1 and slot #2, and the UE2 is scheduled as in fig. 5 (a).

In fig. 5(a) and (b), the UE1 faces the same challenge in determining whether it can transmit. In fig. 5(a), UE1 and UE0 are scheduled in slot 2, but UE1 will detect the energy of UE0 from slot 1 when performing LBT. One strategy to solve the problem in fig. 5(a) may be to introduce gaps in the transmission of UE0, e.g., by scheduling UE0 by the base station to stop some time before the end of slot 1, or by scheduling UE0 and UE1 to resume their transmission a little later after the start of slot 2. This may provide short intervals with no scheduled transmissions, but this may make resources inefficient. In this gap there is also a risk that some other devices occupy the unlicensed resources. This strategy of forcing an interval between scheduling intervals will not work in fig. 5(b) because UE1 starts in slot 2 in the middle of the UE0 transmission process. Thus, when performing LBT, the UE1 will detect the power of the UE 0.

However, according to the procedures described above, if the UE1 can associate the detected resource occupancy and power with the scheduling indication received from the base station, the UE1 may recognize that it is allowed to transmit. Thus, the base station sends an indication of the resource allocation to the UE1 in the relevant time slot in which the UE1 is performing its LBT procedure. For example, if a bitmap format is used, a message "01000" may be sent to UE1 indicating that only interlace 1 is scheduled to be occupied when it is scheduled to perform LBT before starting its transmission. If the estimated resource utilization matches the indication, the UE1 may begin transmitting on interlace 3. Conversely, if the UE1 senses a different resource utilization, it may be determined that the sensed power is from a different source and therefore not allowed to transmit. For example, a different device may already be occupying the spectrum before the UE0 begins its scheduled transmission and therefore may not be able to transmit as scheduled. In one example, a Wi-Fi device may be transmitting in all interlaces. In the described message format, the sensed resource utilization would be "11111".

If the UE0 did not start transmitting, e.g., because the UL grant was lost, and no other devices are utilizing the spectrum, the sensed resource utilization would be "00000". In this case, the sensed utilization does not match the indicated utilization, but the UE may transmit freely since spectrum is available according to LBT measurements. This may be expressed more generally by indicating that the UE is transportable if the sensed resource utilization is a subset of the indicated utilization. The rule also allows for correct transmission by the UE according to the indicated utilization if at least one of the other UEs scheduled by the same base station misses a transmission.

If the UE receives an indication that other UEs are scheduled, but do not detect their transmissions, the UE may perform a short regular LBT (e.g., type 2LBT in the 3GPP standard) before starting the transmission to verify that the spectrum is available. The UE may transmit directly without performing additional regular LBT if the sensing duration for estimating the resource occupancy is not less than the duration of regular LBT and the detected energy has been found to be less than the threshold of regular LBT.

An improvement of the above transmission rule is that the UE is allowed to transmit only if the following two conditions are met: (1) the sensed resource occupancy is the same as or a subset of the indicated resource occupancy; (2) and the difference (e.g., an exclusive or operation of the indicated and sensed resource occupancy indications) is less than a certain number of resources/interlaces.

The threshold may be pre-configured for all UEs according to the specification or sent to each UE by the network, e.g., via RRC signaling. If only zero differences are allowed, the sensed resource utilization must exactly match the indicated resource utilization. If the allowed difference is equal to the number of interlaces, the two conditions, in combination, will allow the UE to transmit if the sensed resource utilization is any subset of the indicated resource utilization.

If the difference between the sensed and indicated resource utilization is below a predetermined threshold, transmission may be allowed instead of allowing transmission if a subset of the indicated resources are utilized. That is, if the difference in the sensed usage amounts is greater than or less than the indicated usage amount reaches a predetermined amount (which may be different for greater than or less than the difference). Such a system also allows transmission to continue if there is a transmission error alarm on an interlace that is not actually used. For example, there may be erroneous measurements or stray energy from users in neighboring cells may be detected. In this case, if one or several interlaces are perceived as used but indicated as unused, transmission may still be allowed, provided the difference is less than a predetermined amount. Further conditions may also be added such that if the allocated resources of the UE are perceived as used, no transmission is allowed, thereby avoiding direct conflicts in resource usage.

In the example of fig. 3, the Wi-Fi device has control over the resources, will induce energy in all interlaced lines, giving a difference greater than the allowed difference, and will therefore not allow transmission.

The proposed NR radio format comprises a series of subcarrier configurations. For example, if the SCS is scaled to 30KHz and 60KHz, respectively, the 20MHz spectrum may provide 10 interlaces for 15KHz subcarrier spacing (SCS), but only 10 and 5 interlaces for 10 RB/interlace. Other interlaced designs with different footprints in time and frequency are possible. The proposed resource utilization indication may require different formats to accommodate the varying number of available interlaces. For example, a bitmap corresponding to the configuration with the largest number of interlaces may be utilized, and information for other SCS-based interlaces may be derived from the bitmap. Another possibility is to design only one bitmap for each specific interlace design.

Fig. 6 shows other examples of resource allocation and utilization. In particular, an example is shown in which the utilization is changed by time slots. In fig. 6(a) and (b), the UE0 begins transmitting at symbol #7 of the first time slot (n). FIG. 6(c) shows an example of a UE0 that is allocated an entire slot, but a UE1 is only allocated minislots; and figure 6(d) shows an example where both UEs are allocated mini/sub-slot resources. In each of these examples, UE1 is scheduled to begin transmission when at least one other UE (UE0) is transmitting; thus, conventional LBT mechanisms will not allow the UE1 to have the right to transmit or not transmit, and therefore need to know which transmissions are related to the same group of devices as the UE1 in order to be able to start a transmission.

Signaling mechanisms are needed to indicate resource utilization to UEs so that they can evaluate their transmission capabilities. Any UE that is associated with a cell that utilizes unlicensed resources and is configured as presently disclosed may benefit from a resource utilization indication.

Group common signaling may be used to send resource utilization to the UEs. Each UE scheduled for transmission or in an RRC active state may be placed in a group by allocating an RNTI. A control resource is allocated that can carry common resource utilization signaling with the allocated RNTI to the UE. Such systems allow sharing of control resources, which may be attractive if there are a large number of UEs scheduling UL transmissions with different starting symbols.

The resource utilization may be sent to the UE using a common DCI message. For example, a common DCI1-C format for which a known fixed RNTI is used may be used, see section 5.3.3.1.4 of 3GPP TS36.212-f 10. Additional fields may be added to the DCI1-C format to carry the utilization information. For example, bitmap fields as described above may be utilized. The DCI provides a subframe configuration for the LAA. The resource utilization information may be provided with triggers as with the current two-level DCI trigger mechanism for PUSCH on LAA in LTE. In this mechanism, which is detailed in section 8.0 of 3GPP TS36.213, the base station sends a first DCI with PUSCH trigger a (using DCI format 0A/0B/4A/4B), which schedules resources for UEs with relative timing and defines a duration in which scheduling is valid. The UE then waits to receive a second trigger named PUSCH trigger B, which provides the UL duration and offset and thus lets the UE calculate its precise scheduling timing information. The PUSCH trigger B is sent in enhanced LAA via DCI format 1C with common RNTI. Thus, PUSCH trigger B is used to activate PUSCH transmission by indicating UL duration and offset for transmission that has been pre-scheduled to users in user-specific DCI with PUSCH trigger a. The proposed resource occupancy indication can be embedded in the PUSCH control mechanism of both stages by adding resource occupancy information in the second DCI, which serves as the second trigger and provides information to the UE for calculating accurate timing information. In this way, the resource utilization indication, although sent in the form of common signaling, may be specific to a particular user.

Although DCI1-C signaling is common (or group common) signaling, the use of triggers helps direct information to a particular UE. Thus, the information is transmitted so that the information can be decoded by the group, but the UE related to the information can use the information. In this sense, general signaling of DCI1-C patterns may be effective when a single user or few users are the target of information. However, when there are a large number of UEs associated with a cell and scheduled in a given interval, the use of group DCI signaling may be less efficient depending on the scheduling scenario and start time of the UE.

Group signaling may be effective if a majority of the UEs (e.g., more than 50% of the UEs, or all UEs) are scheduled to begin transmitting on the same symbol or a smaller subset of symbols. However, this scheme may have limitations if the UE is scheduled to start on a large number of different symbols, since the information related to each different starting symbol is different.

Fig. 7 shows an example of scheduling 4 UEs on 5 interlaces during a slot. UE0 is scheduled to occupy interlace 1 in the entire slot, and both UE1 and UE2 are scheduled on interlace 3, but using different symbols. UE4 is scheduled to transmit on interlace 4 starting at symbol 7. A resource utilization bitmap for each symbol is shown along the bottom of the figure.

If the resource utilization information is sent at the beginning of a slot, it may indicate that only interlace 1 is used (01000), and it may be assumed that this is valid for the duration of the slot. This information is valid for UE1 and UE4, and will enable these UEs to make the correct decision to start transmission if they detect that only interlace 1 is used (assuming sensing is performed immediately before their starting symbol). A longer sensing period may result in the UE4 detecting the transmission of the UE1 and may be one factor in deciding its transmission weights. However, this information is less useful for the UE2 because the interlace utilization immediately before the UE2(01001) that starts transmission is different from the interlace utilization at the start of the slot (01000).

To improve the relevance of the resource utilization information, a time indication may be included. For example, two bits may be used for each interlace, where the first bit u indicates the utilization in the first half of the slot and the second bit indicates the utilization in the second half of the slot. The bitmap for the first half of the slots (associated with UE1 and UE 4) is 01000, while the bitmap for the second half of the slots is 01001 (associated with UE 2). The use of additional bits (e.g., at most one bit per symbol) may improve the accuracy and thus the correlation of the information, but may also increase control overhead. Each UE requires resource utilization only before its allocated starting symbol, and therefore redundant information is transmitted to each UE in this way using additional bits (in the example of 2 bits per slot, each bit is redundant for each UE since the starting symbol of the UE is in the first or second half of the slot, which means that no bits are required for the other half). On the other hand, in some cases, the resource occupancy within a half slot may still be different, and a resource indication may be needed for smaller granularity.

In cases where the starting symbol is wide in range, it may be more efficient to utilize separate UE signaling so that only the required information is transmitted to each UE.

UE-specific resource utilization signaling may be performed with a user-specific DCI message, e.g., the DCI scheduling UL transmissions may also include resource utilization information for the cell. For example, an additional field may be added to the DCI message to indicate resource utilization. In existing standards, DCI formats 0A, 0B, 4A and 4B are used for resource scheduling and may be modified to include resource utilization indications.

The UE-specific signaling allows the information sent to each UE to match the situation that would be encountered when performing its LBT function. That is, the resource utilization may indicate a resource utilization before a scheduling start symbol of the UE. For example, if the UE is scheduled to start its UL transmission in symbol N, resource utilization (e.g., a bitmap as described above) may be provided with respect to symbol N-1, where the UE will perform its LBT function.

Since the symbol time in some radio configurations is short, LBT sensing may be performed on more than one symbol before the start of transmission and thus resource indications may be provided over a longer period of time, e.g., N-2 symbols. It is apparent that the relevant indication points may be defined according to a specific configuration, and the resource utilization may be indicated for the most relevant symbols Nx, where x is an integer defining how many symbols before the starting symbol related to the utilization information may be indicated to the UE, or pre-configured.

Fig. 8 shows an example of UE-specific resource utilization signaling for the same example shown in fig. 7. Assuming that x is 1, the network sends a utilization indication 01000 to UE1 and UE 4. Since UE4 has started transmitting before the start symbol of UE2, the indication sent to UE2 is 01001. Thus, each UE receives a true indication of resource utilization when performing the LBT function, and thus can perform an accurate comparison when determining whether to start transmission.

Even for UEs operating in NR-U, the resource utilization information is not an essential element of each DCI message. Fields containing information may be declared as optional fields there and included in the base station only if they are needed or deemed useful to the UE. The UE may be configured to blindly decode two DCI formats, one with utilization information and one without utilization information, and if included, use this information as needed. Blind decoding may increase some processing overhead but can reduce control signaling overhead. Alternatively, each UE may be configured to expect or not expect utilization information in its DCI message. For example, the network may use RRC signaling to configure the UE to decode the larger DCI with the resource indication.

Another signaling protocol includes a flag in a DCI message that schedules UL transmissions. The flag indicates whether a second DCI message including resource utilization information is to be transmitted. This protocol reduces the overhead in the first DCI always sent to a single bit and allows UE-specific utilization information to be sent in the second DCI message only when needed or useful. In one variation, the second DCI message may be directed to a group of UEs having the same starting symbol or other grouping that may be useful.

The above-described techniques are equally applicable to beam scanning systems. However, due to physical limitations and beamforming capabilities of the UE, it may be more likely that the UE may perceive transmissions from the UE in neighboring beams when performing LBT. Thus, even though the UE may be free to transmit within its beam area, the UE may detect a mismatch between the resource indication from the base station and the sensed resource utilization.

This situation can be mitigated by the base station including the resource utilization from the adjacent beams in the information transmitted to the UE. The base station has complete scheduling information for all beams and knows the location of the UEs, so it can reasonably estimate the signal that each UE can detect. The indicated resource utilization may thus comprise resources utilized by different beams but likely to be detected by the UE.

As described above, for grant based UL transmissions, the base station is aware of all scheduled transmissions and can therefore provide an accurate indication of scheduling resource utilization. However, in the case of unlicensed transmissions, a base station that is semi-persistently scheduled or has configured grants may configure periodic resources to be available to the UE, and the UE decides whether to use those resources according to its transmission needs. In this case, the base station does not know which resources will actually be used for UL in each symbol, but only certain resources may be utilized. The above system will allow the indication of the resources that may be used in each symbol, but the indication may be inaccurate, depending on the choice of each UE using or not using its allocated resources.

The base station may indicate resource utilization to the UE based on the configuration grant using a group common DCI that is decodable by each user configured for configuration grant transmission. The indication as to whether they require the resource occupancy indication may be part of a setting based configuration authorization.

As described above, the base station does not know whether each UE will actually use the allocated resources, and thus cannot give an indication of the determination. However, the base station knows which resources can be utilized and can indicate this to each UE using the techniques described above. If resources have already been allocated to the UE, they are indicated as utilized in the utilization indication.

The UE may be configured to apply the subset rule discussed above such that the UE is allowed to transmit if the sensed resources are a subset of the indicated resources. Sensing a subset of indicated resources indicates that some allocated resources are unused and differences between the sensed and indicated resources should not prevent transmission.

In an alternative signaling protocol, the indication field may include three options-idle, busy, or configured for transmission based on configuration authorization. This provides the UE with a more accurate indication of the resource configuration, thus allowing more efficient comparisons and decisions.

The standard has a standardized bandwidth part (BWP) operation, where the base station may configure the UE with multiple parts of the carrier bandwidth, and one of these parts may be activated by the base station. The activation may be performed by RRC signaling or DCI-based signaling. BWP operation facilitates UE operation with large carrier bandwidth. This is also true in unlicensed bands where very large bandwidth is available. Resource occupancy indication signaling is provided with respect to active BWP for a relevant UE if the UE has been configured to operate using BWP in the unlicensed band.

Throughout this disclosure, embodiments have been described for a 5G NR system. The reader will appreciate that the disclosed principles and methods are applicable to any system that operates with efficient user reuse over unlicensed spectrum. One example is LTE, where future enhancements may use the methods disclosed herein. Since the short TTI has been incorporated into LTE, if users scheduled for short TTI UL transmissions have to be multiplexed, the problem is similar to that addressed here and can be solved by the principles described in this disclosure.

Although not shown in detail, any device or apparatus forming part of a network may include at least a processor, a memory unit, and a communication interface; wherein the processor unit, the memory unit and the communication interface are configured to perform the method of any aspect of the invention. Further options and selections are described below.

The signal processing functions of embodiments of the present invention, particularly the gbb and the UE, may be implemented using computing systems or architectures known to those skilled in the relevant art. Computing systems such as desktop, laptop or notebook computers, handheld computing devices (PDAs, cell phones, palmtops, etc.), mainframes, servers, clients, or any other type of special or general purpose computing device may be used as may be desired or appropriate for a given application or environment. The computing system may include one or more processors, which may be implemented using a general-purpose or special-purpose processing engine such as, for example, a microprocessor, microcontroller or other control module.

The computing system may also include a main memory, such as a Random Access Memory (RAM) or other dynamic memory, for storing information and instructions to be executed by the processor. Such main memory may also be used for storing temporary variables or other intermediate information during execution of instructions to be executed by the processor. The computing system may also include a Read Only Memory (ROM) or other static storage device for storing static information and instructions for the processor.

The computing system may also include an information storage system that may include, for example, a media drive and a removable storage interface. The media drive may include a drive or other mechanism to support fixed or removable storage media, such as a hard disk drive, a floppy disk drive, a magnetic tape drive, an optical disk drive, a read-write drive (R or RW) for a Compact Disc (CD) or Digital Video Drive (DVD), or a drive for other removable or fixed media. The storage media may include, for example, a hard disk, floppy disk, magnetic tape, optical disk, CD or DVD, or other fixed or removable medium that is read by and written to by a media drive. The storage media may include a computer-readable storage medium having stored therein particular computer software or data.

In alternative embodiments, the information storage system may include other similar components for allowing computer programs or other instructions or data to be loaded into the computing system. Such components may include, for example, removable storage units and interfaces (e.g., program cartridges and cartridge interfaces), removable storage (e.g., flash memory or other removable memory modules) and memory slots, and other removable storage units and interfaces that allow software and data to be transferred from the removable storage unit to the computing system.

The computing system may also include a communication interface. Such a communication interface may be used to allow software and data to be transferred between the computing system and external devices. Examples of a communication interface may include a modem, a network interface (e.g., an ethernet or other NIC card), a communication port (e.g., a Universal Serial Bus (USB) port), a PCMCIA slot and card, etc. Software and data transferred via the communications interface are in the form of signals which may be electronic, electromagnetic, optical or other signals capable of being received by the communications interface medium.

In this document, the terms "computer program product," "computer-readable medium," and the like may be used generally to refer to tangible media, such as memory, storage devices, or storage units. These and other forms of computer-readable media may store one or more instructions for use by a processor, including a computer system, to cause the processor to perform specified operations. Such instructions 45, generally referred to as "computer program code" (which may be grouped in the form of computer programs or other groupings), when executed, enable the computing system to perform functions of embodiments of the present invention. Note that the code may directly cause the processor to perform specified operations, be compiled to perform the operations, and/or be combined with other software, hardware, and/or firmware elements (e.g., libraries for performing standard functions) to perform the operations.

The non-transitory computer readable medium may include at least one of the group consisting of: hard disks, CD-ROMs, optical storage devices, magnetic storage devices, read-only memories, programmable read-only memories, erasable programmable read-only memories, EPROMs, electrically erasable programmable read-only memories and flash memories. In implementations in which these elements are implemented using software, the software may be stored in a computer-readable medium and loaded into the computing system using, for example, a removable storage drive. When executed by a processor in a computer system, the control module (in this example, software instructions or executable computer program code) causes the processor to perform the functions of the invention as described herein.

Furthermore, the inventive concept can be applied to any circuit that performs a signal processing function within a network element. It is further contemplated that a semiconductor manufacturer may employ the inventive concept in the design of a stand-alone device such as a microcontroller of a Digital Signal Processor (DSP), or an Application Specific Integrated Circuit (ASIC), and/or any other subsystem element, for example.

It will be appreciated that the above description, for clarity, has described embodiments of the invention with reference to a single processing logic. The inventive concept may, however, be equally implemented by a plurality of different functional units and processors to provide the signal processing functions. Hence, references to specific functional units are only to be seen as references to suitable means for providing the described functionality rather than indicative of a strict logical or physical structure or organization.

Aspects of the invention may be implemented in any suitable form including hardware, software, firmware or any combination of these. The invention may optionally be implemented at least partly as computer software running on one or more data processors and/or digital signal processors, or configurable modular components such as FPGA devices.

Thus, the elements and components of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way. Indeed the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the invention is limited only by the appended claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term "comprising" does not exclude the presence of other elements or steps.

Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor. Additionally, although individual features may be included in different claims, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. Likewise, the inclusion of a feature in one claim category does not imply a limitation to this category but rather indicates that the feature is equally applicable to other claim categories as appropriate.

Furthermore, the order of features in the claims does not imply any specific order in which the features must be performed and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order but rather that the steps may be performed in any suitable order. In addition, singular references do not exclude a plurality. Thus, references to "a", "an", "first", "second", etc., do not preclude a plurality.

Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the invention is limited only by the appended claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the terms "comprising" or "including" do not exclude the presence of other elements.

Claims

1. A method of resource sharing in a cellular communication system, the method being performed by a base station and comprising the steps of: sending an indication from a base station to a UE indicating resources available for Uplink (UL) transmissions from the UE to the base station; transmitting, from the base station to the UE, an indication of UL transmission resources allocated to other UEs associated with the base station during a time period prior to a start of resources indicated as available to the UE for UL transmissions.

2. The method of claim 1, wherein the resource is in an unlicensed frequency band.

3. The method of claim 1 or claim 2, wherein the resource comprises a plurality of interlaced lines.

4. The method according to any of the preceding claims, wherein the indication on UL transmission resources allocated to other UEs comprises a bitmap field.

5. The method of claim 4, wherein each bit of the bitmap corresponds to a set of physical resources.

6. The method of claim 5, wherein the groups of physical resources are interlaced.

7. The method of any preceding claim, wherein the indication of UL transmission resources allocated to other UEs is sent in a DCI message common to a group.

8. The method of claim 7, wherein the group-common DCI message is a DCI message in DCI1-C format.

9. The method of any of claims 1-6, wherein the indication about UL transmission resources allocated to other UEs is sent in a UE-specific DCI message.

10. The method of claim 9, wherein the UE-specific DCI message is a DCI message further comprising an indication of resources available for transmission from the UE to the base station.

11. The method according to any of claims 1-6, wherein the indication on resources available for transmission from the UE to the base station comprises an indication on a subsequent message indicating UL transmission resources allocated to other UEs.

12. The method of any preceding claim, wherein the UL transmission resources allocated to other UEs comprise resources allocated for transmission based on a configured grant.

13. The method of any preceding claim, wherein the UL transmission resources allocated to other UEs comprise resources allocated to UEs associated with the base station but operating in different beams than the UEs.

14. A method as claimed in any preceding claim, wherein the resource indication is a resource occupancy for a symbol preceding a first symbol of resources allocated by the UE.

15. The method of any preceding claim, wherein the indication of UL transmission resources allocated to other UEs comprises a utilization rate in a plurality of different times.

16. The method of any preceding claim, wherein the time period is a Listen Before Talk (LBT) time period for the UE.

17. A method of resource sharing in a cellular communication system, the method being performed by a UE and comprising the steps of: receiving an indication from a base station indicating resources available for Uplink (UL) transmissions from the UE to the base station; receiving, from the base station, an indication of UL transmission resources allocated to other UEs associated with the base station during a time period prior to a start of resources indicated as available to the UEs for UL transmissions.

18. The method of claim 17, wherein the resource is in an unlicensed frequency band.

19. The method of claim 17 or claim 18, wherein the resource comprises a plurality of interlaced lines.

20. The method according to any of claims 17-19, wherein the indication on UL transmission resources allocated to other UEs comprises a bitmap field.

21. The method of claim 20, wherein each bit of the bitmap corresponds to a set of physical resources.

22. The method of claim 21, wherein the groups of physical resources are interlaced.

23. The method according to any of claims 17-22, wherein the indication on UL transmission resources allocated to other UEs is received in a DCI message common to a group.

24. The method of claim 23, wherein the DCI message common to the groups is a DCI message in DCI1-C format.

25. The method according to any of claims 17-22, wherein the indication on UL transmission resources allocated to other UEs is received in a UE-specific DCI message.

26. The method of claim 25, wherein the UE-specific DCI message is a DCI message further comprising an indication of resources available for transmission from the UE to the base station.

27. The method according to any of claims 17-26, wherein the indication on resources available for transmission from the UE to the base station comprises an indication on a subsequent message indicating UL transmission resources allocated to other UEs.

28. The method according to any of claims 17-27, wherein the UL transmission resources allocated to other UEs comprise resources allocated for transmission based on a configured grant.

29. The method of any of claims 17-28, wherein the UL transmission resources allocated to other UEs comprise resources allocated to UEs associated with the base station but operating in different beams than the UEs.

30. The method according to any of claims 17-29, wherein the resource indication is a precise resource occupancy for a symbol preceding a first symbol of a resource to which the UE is allocated.

31. The method according to any of claims 17-30, wherein the indication on UL transmission resources allocated to other UEs comprises a utilization in a plurality of different times.

32. The method of any of claims 17-31, further comprising the steps of: performing an LBT procedure to identify utilized resources in an LBT period, wherein the UL is transmitted only in its allocated UL transmission resources if the utilized resources are the same as resources indicated as allocated to other UEs.

33. The method of any of claims 17-31, further comprising the steps of: performing an LBT procedure to identify utilized resources in an LBT period, wherein the UL is transmitted only in its allocated UL transmission resources if the utilized resources are the same as or a subset of resources indicated as allocated to other UEs.

34. The method of any of claims 17-31, further comprising the steps of: performing an LBT procedure to identify utilized resources in an LBT period, wherein the UL is transmitted only in its allocated UL transmission resources if the utilized resources differ from resources indicated as allocated to other UEs by less than a predetermined threshold.

35. The method according to any of claims 17-34, wherein the time period is a listen before transmission time period for the UE.

36. A base station for performing the method of any one of claims 1-16.

37. A UE for performing the method of any of claims 17-35.