WO2009022293A2

WO2009022293A2 - Variable transmission structure for reference signals in uplink messages

Info

Publication number: WO2009022293A2
Application number: PCT/IB2008/053227
Authority: WO
Inventors: Xiang Guang Che; Chun Yan Gao (Adele)
Original assignee: Nokia Corporation; Nokia, Inc.
Priority date: 2007-08-14
Filing date: 2008-08-12
Publication date: 2009-02-19
Also published as: WO2009022293A3

Abstract

A NodeB signals a user equipment UE, based on the UE speed, to use a first or a second transmission scheme for its ACK/NACK/CQI transmissions. The first transmission scheme is better suited to higher speed UEs and uses infra-transmission time interval (intra-TTI) hopping of reference signals and no orthogonal cover code. The second transmission scheme does not use intra-TTI hopping and uses an orthogonal cover code. There is a different cyclic shift among the different transmission schemes. UEs transmit their ACK/NACK/CAI with the scheme they were signaled. The Node B maps the ACKs/NACKs/CQIs received from those UEs using the first transmission scheme to related control channel indices, and separately maps the ACKs/NACKs/CQIs received from those UEs using the second transmission scheme to related control channel indices. The NodeB may signal two indications: one to hop or not; the other to tell how many cyclic shifts to use for the hopping.

Description

VARIABLE TRANSMISSION STRUCTURE FOR REFERENCE SIGNALS IN UPLINK MESSAGES

TECHNICAL FIELD:

[0001] The exemplary and non-limiting embodiments of this invention relate generally to wireless communications systems and, more specifically, relate to transmission/reception of reference sequences such as Zadoff Chu CAZAC sequences sent in messages from a user equipment to a network node, particularly ACKTNACK and CQI messages sent on an uplink control channel.

BACKGROUND:

[0002] The following abbreviations are herewith defined

3GPP third generation partnership project

ACK acknowledgement

BCH broadcast channel

BLER block error rate

CAZAC constant amplitude zero auto-correlation

CDM code division multiplex

CP cyclic prefix channel quality indication

DFT discrete Fourier transform

DM demodulation e- evolved (also known as LTE)

FDM/FDMA frequency division multiplex/multiple ace

ΓFFT inverse fast Fourier transform

LTE long term evolution (also known as 3.9G)

NACK negative ACK

Node B base station or BS

OFDM orthogonal frequency division mutiplex

PUCCH physical uplink control channel

RAN radio access network

RLC radio link control

RRC radio resource control

RS reference signal

RU resource unit

SIMO single input multiple output

TTI transmission time interval

UE user equipment

UL uplink UMTS universal mobile telecommunications system

UTRAN UMTS terrestrial radio access network

V-MIMO virtual multiple input/multiple output

ZC Zadoff-Chu

[0003] Reference can be made to 3GPP TR 25.814, V7.1.0 (2006-09); TECHNICAL

SPECIFICATION GROUP RADIO ACCESS NETWORK; PHYSICAL LAYER ASPECTS FOR EVOLVED UNIVERSAL TERRESTRIAL RADIO ACCESS (UTRA) (Release 7), such as generally in section 9.1 for a description of the SC-FDMA UL of e-UTRA (Section 9 is attached as Exhibit A to the priority document, US provisional patent application no. 60/964,621 , filed August 14, 2008).

[0004] More specifically, as is described in Section 9.1 of3GPP TR25.814, the basic uplink transmission scheme is single-carrier transmission (SC-FDMA) with cyclic prefix to achieve uplink inter-user orthogonality and to enable efficient frequency-domain equalization at the receiver side. Frequency-domain generation of the signal, sometimes known as DFT-spread OFDM (DFT S-OFDM), is assumed and illustrated in Figure IA, which reproduces Figure 9.1.1-1 of 3GPP TR 25.814. This approach allows for a relatively high degree of commonality with the downlink OFDM scheme and the same parameters, e.g., clock frequency, can be reused.

[0005] The Zadoff-Chu CAZAC sequence has been agreed upon as the pilot sequence for the LTE UL. ZC sequences and their modified versions (i.e., truncated and/or extended ZC sequences) are therefore used as reference signals RS in the LTE uplink system, and will also be used on the physical uplink control channel (PUCCH). It has been decided in 3GPP that data-non-associated control signals such as ACK/NACK and CQI will be transmitted on PUCCH by means of ZC sequences, described at "MULTIPLEXING OFL1/L2 CONTROL SIGNALS BETWEEN UES IN THE ABSENCE OF UL DATA" (3GPP TSG RAN WGl Meeting #47bis, Sorrento, Italy; January 15-19, 2007 by Nokia, document Rl -070394), attached to the priority document as Exhibit B. Multiple UEs in a given cell share the same Zadoff-Chu sequence while keeping the orthogonality by using a cyclic shift specific to each UE. In this manner different ones of the UEs in a cell may multiplex their UL transmissions (e.g., non-data associated UL transmissions) on the same frequency and time resource (physical resource block/unit or PRB/PRU; currently 180 kHz in LTE). The orthogonality of the ZC sequences enables the receiving Node B to discern the signals of the different UEs from one another.

[0006] Orthogonality is achieved by cyclically shifting the CAZAC mother or base code, so orthogonality between different code channels varies widely; the best orthogonality is achieved between the code channels which have the largest difference in cyclic shift domain whereas the worst orthogonality is between two adjacent cyclic shifts. The same issue is related also to the cyclic shifts of block-level spreading codes (see document Rl -070394: "MULTIPLEXING OF L1/L2 CONTROL SIGNALS BETWEEN UES IN THE ABSENCE OF UL DATA"; Exhibit B of the priority document and referenced above).

[0007] Both FDD and TDD are considered in LTE, which uses two frame structures: frame structure 1 FSl and frame structure 2 FS2. Due to the difference in FDD versus TDD frame structure and duplex mode, some designs for FDD and TDD can be different, hi FDD, the structure for DL ACK/NACK signals transmitted in the UL PUCCH is generally agreed upon, and uses CAZAC sequence modulation and block spreading for ACK/NACK. It is agreed in RANl #48bis that there will be 3 RS for ACK transmission (see 3GPP TSG RAN WGl Meeting #49, Kobe Japan, 7-11 May 2007, DRAFT REPORT OF 3GPP TSG RAN WGl #48B V0.3.0, document Rl -072001 attached to the priority document as Exhibit C]. InRANl #49 it is agreed that for non-persistent scheduling the ACK/NAK resource is linked to the index of the control channel used for scheduling [see Draft Report of 3GPP TSG RAN WGl #49b vθ.1.0, Orlando, Florida-USA 25-29 June 2007, document Rl -072646, attached to the priority document as Exhibit D].

[0008] In TDD with FS2, since the number of OFDM symbols is different from that of

FDD, the design of the ACK/NACK transmission structure can also be different, hi TDD with FS2 and assuming the same CAZAC and block spreading structure for ACK transmission as in FDD, there are 9 OFDM symbols with a short CP. Therefore the multiplexing capacity is determined by the lesser of a) the number of OFDM symbols for R.S and b) the number of OFDM symbols for ACK/NACK. So assigning four or five OFDM symbols for RS and the others for ACK/NACK will give the largest capacity. Assuming a total of six cyclic shifts of the CAZAC sequence can be used, then the multiplexing capacity is 24 UEs.

[0009] Similarly, as can be seen at document Rl -072646: "DRAFT REPORT OF 3GPP

TSG RAN WGl #49b vθ.1.0" (Exhibit D of the priority document and referenced above), the CAZAC based CQI scheme on PUCCH for LTE was agreed for the RS position as shown in Figure IB for CQI transmission in PUCCH in LTE FDD and TDD FSl with a short CP. It remains unresolved (for both FDD and TDD) whether the RS will use an orthogonal cover code. Additionally unresolved is the number of OFDM symbols for RS transmission and whether there should be intra-TTI hopping for FS2. A higher number of RS symbols will give better channel estimation performance but will decrease symbol space for CQI transmission and cause a higher coding rate, which will degrade the BLER performance. Assuming a short CP as for ACK/NACK above, there are nine OFDMs per TTI, and the symbol space is much less than that in FDD (a total of fourteen OFDM symbols and twelve OFDM symbols for data).

[0010] The inventors have found a problem in that under certain conditions these are not seen to give adequate performance in CQI and ACK/NACK transmissions.

SUMMARY:

[0011] In accordance with one exemplary embodiment of the invention is a method that includes determining a speed of a user equipment, selecting a first transmission scheme or a second transmission scheme for the user equipment based on the determined speed where the first transmission scheme uses intra-transmission time interval hopping of reference signals and the second transmission scheme uses no intra-transmission time interval hopping of reference signals, and signaling the user equipment an indication of the selected transmission scheme for a data non-associated uplink control transmission. In various embodiments for the case where a network node executes this method, the speed can be determined by the network node itself by measurement or it may be determined from a speed indication received in signaling from the user equipment.

[0012] In accordance with another exemplary embodiment of the invention is a memory storing computer-readable instructions executable by a processor for performing actions directed to determining a first or second transmission scheme for a user equipment. In this embodiment the actions include determining a speed of a user equipment; selecting a first transmission scheme or a second transmission scheme for the user equipment based on the determined speed, where the first transmission scheme uses intra-transmission time interval hopping of reference signals and the second transmission scheme uses no intra-transmission time interval hopping of reference signals; and signaling the user equipment an indication of the selected transmission scheme for a data non-associated uplink control transmission.

[0013] In accordance with a further exemplary embodiment of the invention is an apparatus that includes one of a processor configured to determine a speed of a user equipment and/or a receiver to receive from a user equipment a speed of the user equipment. In the apparatus the processor is further configured to select a first transmission scheme or a second transmission scheme for the user equipment based on the user equipment speed, where the first transmission scheme uses intra-transmission time interval hopping of reference signals and the second transmission scheme uses no intra-transmission time interval hopping of reference signals. The apparatus also includes a transmitter that is configured to signal the user equipment an indication of the selected transmission scheme for data non-associated uplink control transmissions.

[0014] In accordance with a still further exemplary embodiment of the invention is a method that includes receiving an indication whether to use a first transmission scheme or a second transmission scheme for data-non-associated control signaling, where the first transmission scheme uses intra-transmission time interval hopping of reference signals and the second transmission scheme uses no intra-transmission time interval hopping of reference signals; and sending a data non-associated control message on an uplink control channel using the first or second transmission scheme according to the received indication.

[0015] In accordance with still another exemplary embodiment of the invention is a memory storing computer-readable instructions executable by a processor for performing actions directed to determining a first or second transmission scheme for a transmission. In this particular embodiment the actions include receiving an indication whether to use a first transmission scheme or a second transmission scheme for data-non-associated control signaling, where the first transmission scheme uses intra-transmission time interval hopping of reference signals and the second transmission scheme uses no intra-transmission time interval hopping of reference signals; and sending a data non-associated control message on an uplink control channel using the first or second transmission scheme according to the received indication.

[0016] In accordance with yet another exemplary embodiment of the invention is an apparatus that includes a receiver and a transmitter. The receiver is configured to receive an indication whether to use a first transmission scheme or a second transmission scheme for data-non-associated control signaling, where the first transmission scheme uses intra- transmission time interval hopping of reference signals and the second transmission scheme uses no intra-transmission time interval hopping of reference signals. The transmitter is configured to send a data non-associated control message on an uplink control channel using the first or second transmission scheme according to the received indication.

[0017] In accordance with one exemplary embodiment of the invention is an apparatus that includes processing means and sending means. The processing means is for determining from a received indication whether to use a first transmission scheme or a second transmission scheme for data-non-associated control signaling, where the first transmission scheme uses intra-transmission time interval hopping of reference signals and the second transmission scheme uses no intra-transmission time interval hopping of reference signals. The sending means is for sending a data non-associated control message on an uplink control channel using the first or second transmission scheme according to the received indication. In particular implementations of this embodiment, the processing means includes a receiver and a processor, and the sending means includes a transmitter. As shown the illustrations, the transmitter and receiver may be implemented together as a transceiver.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0018] Embodiments of the invention are detailed below with particular reference to the attached drawing Figures.

[0019] Figure IA reproduces Figure 9.1.1-1 of3GPP TR 25.814, and shows frequency domain generation of the transmitted signal for the 3GPP LTE SC-FDMA UL. [0020] Figure IB is an agreed CQI transmission structure in PUCCH for FDD and

TDD for frame structure 1.

[0021] Figure 2 is a simplified block diagram of various electronic devices that are suitable for use in practicing the exemplary embodiments of this invention. [0022] Figures 3 A is an example of a frame structure showing RS for ACK without intra-TTI hopping according to an embodiment of the invention.

[0023] Figure 3B is an example of a frame structure showing RS for ACK with intra-

TTI hopping according to an embodiment of the invention.

[0024] Figures 4A-B are tables showing an exemplary resource mapping for the embodiment of Figures 3 A-B (Figure 4A) and for symbol cyclic shift hopping for RS (Figure 4B).

[0025] Figure 5A-B illustrate two CQI transmission structures for TDD FS2, where

Figure 5A is RS with an orthogonal cover and Figure 5B is a RS with intra-TTI hopping and no cover.

[0026] Figure 6 is a graph of BLER versus signal to noise ratio SNR illustrating CQI transmission performance for various hop and spreading scenarios. [0027] Figure 7 is a process flow diagram illustrating an exemplary aspect of the invention. DETAILED DESCRIPTION:

[0028] The inventors have found that the performance of the four RS or five RS structure degrades greatly at high UE speed, e.g, 350km/h. Such speeds are not to be discounted in LTE as certain relay stations may be disposed in, for example, a high-speed train or the like. The ACK/NACK transmission with intra-TTI hopping can improve the performance at high speed, but ACK/NACK multiplexing capacity will decrease by half as compared to non-hopping since fewer block spreading codes would be available. How to maximize the ACK/NACK multiplexing capacity while at the same time getting satisfactory performance for high speed UEs and UEs with a coverage problem is a problem addressed herein.

[0029] Below is detailed a RS structure for DL ACK/NACK transmitted in UL

PUCCH in TDD with FS2 and the corresponding signaling to aid the ACK resource mapping. This is the structure for ACK/NACK only signals without UL data and the periodic CQI. Although the LTE TDD FS2 is used throughout the below description as an example to illustrate the solution, this is only exemplary and the solution is applicable for both FSl and FS2 with FDD and TDD operation.

[0030] The inventors also studied the BLER performance of CQI with the agreed structure of Figure IB in TDD FS2 and found that if the UE speed is low, the five bit CQI transmitted with four RS and without intra-TTI hopping and with an orthogonal cover code in time gives better performance as compared with other schemes. However, if the UE speed is high as above, the orthogonality of the cover in time will be destroyed and the performance without the orthogonal cover and with intra-TTI hopping gives better performance. Results are shown at Figure 6 and detailed below. A simple threshold may be used so that those UEs whose speed exceeds the threshold use no orthogonal cover and intra-TTI hopping for their data non-associated control signaling (UE transmissions of ACK/NACK/CQI that are sent on the UL without data) and those UEs whose speed is below the threshold use the orthogonal cover code and intra-TTI hopping for their data non-associated control signaling. [0031] In a related vein, the nine OFDMs per TTI and the lesser symbol space noted above in background is seen to degrade the CQI transmission performance. For the fixed nine OFDM symbols per TDD TTI, there should be a tradeoff between the number of RS and the coding rate, both of which will affect the transmission BLER of CQI.

[0032] In summary, for data non-associated UL transmissions (both ACK/NACK and

CQI), a single transmission scheme is not seen as optimum for both low speed and high speed UEs.

[0033] The solution for these data non-associated UL transmissions is detailed further below. First, reference is made to Figure 2 for illustrating a simplified block diagram of various electronic devices that are suitable for use in practicing the exemplary embodiments of this invention. In Figure 2 a wireless network 9 is adapted for communication with a UE 10 via a Node B (base station) 12. The network 9 may include a serving gateway GW 14, or other radio controller function known in various systems as a radio network controller, a mobility management entity, or the like. The UE 10 includes a data processor (DP) 1OA, a memory (MEM) 1OB that stores a program (PROG) 1OC, and a suitable radio frequency (RF) transceiver 1OD for bidirectional wireless communications over one or more links 16 via one or more antennas 1OE (one shown) with the Node B 12, which also includes a DP 12A, a MEM 12B that stores a PROG 12C, and a suitable RF transceiver 12D and at least one antenna 12E (one shown). The Node B 12 maybe coupled via a data path 18 (e.g., Iub) to the serving or other GW 12, which itself includes a DP 14A coupled to a MEM 14B storing a PROG 14C. The GW 14 may then be coupled via another data interface to a core network (not shown) as well as to other GWs. At least one of the PROGs 1OC, 12C and 14C is assumed to include program instructions that, when executed by the associated DP, enable the electronic device to operate in accordance with the exemplary embodiments of this invention, as will be discussed below in greater detail. In general, the exemplary embodiments of this invention may be implemented by computer software executable by the DP 1 OA of the UE 10 and the other DPs, or by hardware, or by a combination of software and/or firmware and hardware. [0034] In general, the various embodiments of the UE 10 can include, but are not limited to, cellular telephones, personal digital assistants (PDAs) having wireless communication capabilities, portable computers having wireless communication capabilities, image capture devices such as digital cameras having wireless communication capabilities, gaming devices having wireless communication capabilities, music storage and playback appliances having wireless communication capabilities, internet appliances permitting wireless Internet access and browsing, as well as portable units or terminals that incorporate combinations of such functions.

[0035] The MEMs 1OB, 12B and 14B may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The DPs 1OA, 12A and 14A may be of any type suitable to the local technical environment, and may include one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on a multi-core processor architecture, as non-limiting examples.

[0036] Now is described an exemplary solution to the ACK/NACK problem. The solution to the CQI problem follows closely. To maximize the ACK/NACK multiplexing capacity and at the same time satisfy the performance of high speed UEs and coverage demanding UEs, an embodiment of this invention uses a hybrid structure of intra-TTI hopping and non-hopping for DL ACK/NACK transmitted in the PUCCH. Specifically:

^■ For ACK/NACK transmitted in PUCCH, an intra-TTI hopping structure is used for high speed UEs and a non-hopping structure is used for low speed UEs; and

^■ The intra-TTI hopping structure and the non-hopping structure are assigned different cyclic shifts of CAZAC in frequency domain.

[0037] Assume for example a five RS structure for non-hopping as in Figure 3A and a (3+2) RS structure for intra-TTI hopping as in Figure 3B, and a total of six cyclic shifts used for ACK/NACK transmission. Then the multiplexing capacity will be

Mux_Cap = 4*N+2*(6-N) = 12+2*N where N is the number of cyclic shifts for the non-hopping structure [0 =< N <= 6]. As is obvious by comparing to the capacity detailed in the background section, this multiplexing capacity is larger than that of the intra-TTI hopping only structure, which is 12 [12 =< Mux_Cap <= 24].

[0038] The ACK resource may be signaled and mapped (implicitly) as follows, hi

FDD, it is agreed that the ACK/NAK resource is linked to the index of the control channel used for scheduling. That is, the UL scheduling grant is sent on a control channel in a DL subframe that maps by that index to the UL subframe being granted. Such mapping is implicit, as seen in 3GPP TSG RAN WGl MEETING #49BIS; SIGNALING OF IMPLICIT ACK/NACK RESOURCES; Orlando, USA June 25-29, 2007; by Nokia Siemens Networks and Nokia, document Rl -73006 (Exhibit E of the priority document). For an intra-TTI hopping or a non-hopping only structure, such implicit mapping can be applied directly. But this mapping poses a bit of a problem with the above hybrid structure. Additional signaling detailed below is offered to aid the mapping and resolve this issue:

^■ Hop indication: This field is at least a 1 bit indication sent by the Node B to the UE in each DL scheduling grant to indicate whether its ACK will be sent with hopping or not hopping. For example, Hopjndication=\ means intra-TTI Hopping and Hop_indication=0 means non-hopping. This indication can also be semi-statically configured together with the following semi-static parameters;

^■ Num_Hop: This field (exemplary 3 bits) is sent by the Node B to the UE and indicates how many cyclic shifts are used for hopping. It may be semi-static and need only be signaled when the number of cyclic shifts for that UE 's non- data associated UL signaling to the Node B changes. This field may therefore be transmitted in dynamic BCH or RRC signaling. With these two additional inputs, the calculation of the ACK resource can be done in a similar way as detailed at document Rl -73006: "SIGNALING OF IMPLICIT ACK/NACK RESOURCES (Exhibit E of the priority document and referenced above) with similar static and semi-static input parameters as follows.

[0039] Static input parameters [as detailed at sections 3-4 of document Rl-73006]:

• num_t_shift: number of cyclic shifts of block spreading code (e.g., 3 or 4)

• numj_shift: number of cyclic shifts of frequency domain CAZAC code

(numj_shift = 12).

[0040] Semi-static input parameters [as detailed at sections 3-4 of document Rl-

73006]:

• res_lst: resource number of the first implicit resource. The applied resource numbering is presented in Figure 2 of document Rl-73006.

» shift_diffi cyclic shift difference between two implicit resources. When the desired allocation order is e.g., [0, 3, 6, 9, ...], then shift_diff equals to 3.

• impl_ores: resource number for ACK/NACK, tied to the DL control channel index and signaled implicitly, [0, 1, 2, ...].

[0041] Now the differences over the detail provided at document Rl-73006 are as follows. A) Since the intra-TTI hopping and the non-hopping structure have a different number of OFDM symbols for RS and data, then the numjt_shift parameter can be different for the intra-TTI hopping and the non-hopping structures, and should be indicated separately as numJ_shift_Hop and numJ_shift_noHop. B) The

with the additional input Num_Hop, may be used to derive the numJ_shift_Hop and num_t_shift_noHop parameter as follows: numJ_^' shift_Hop^:=Num_Hop; and

numJ_^~ shift-Num_Hop. C) Additionally there may be another parameter impljres for intra-TTI hop and non-hopping UEs separately, denoted by impl_res_hop and impl_res_nohop respectively. The control channel index for these may be calculated separately.

[0042] If the parameter Hopjndication is sent in a scheduling grant, for the UE with the hop, the control channel index is obtained by calculating only the UEs with Hop_indication=l in the scheduling grant. For a UE without the hop, the control channel index is obtained by calculating only the UEs with Hop_indication=0 in the scheduling grant. \fHop_indication is sent as a semi-static parameter, then the Node B will separate scheduling grants for high speed UEs from those for low speed UEs in a different space, and the border between them can be known by the UE based on the Num_Hop parameter. Based on that the impl_resjιohop and impl_res_hop parameters can be derived.

[0043] One exemplary algorithm to calculate the ACK resource {shift J and shift J) is illustrated as follows:

shift_t_Hop = mod (floor( i_temp_Hop I num_f_shift_Hop), num_t_shift_Hop) (1)

shiftjjϊop= mod ( ijempjiop + shift_t_Hop + mod ( floor( impl_res_Hop * shift_diff/ num_res Hop ), shift_diff), numj_shiftjϊop ), (2)

shift JjioHop = mod ( floor( i_temp_noHop I numJ_shift_noHop), numJjshift noHop)

(3)

shift J JιoHop= Num Hop+τaod ( iJempjioHop + shift J _noHop+ mod ( floor( impl_res_noHop * shift_diff/ num_res_noHop ), shift_dijf), numJ_shift_noHop ), (4)

where num_res_Hop = num_ t_shift * numJ_^' shift_Hop (5)

ijempjiop — resjst _Hop+ {impl resJJop * shift _diff). (6) num_f_shift_Hop= Numjlop; (7)

resJst_Hop=res lst ; (8)

num resjioHop = numjjshifl * numJ^"_shift_noHop; (9)

iJempjioHop = res_ lst _noHop+ (impljes noHop * shift jiiff); (10)

numj^"_shift -Numjlop; (11)

resJstjioHop- res_lst; (12)

[0044] When there is a per-symbol cyclic shift hopping for RS, the required signaling will not change, but the calculation of the ACK/NACK resource mapping will be different. In such a case, it is advantageous to have a predefined cyclic shift hopping pattern for any value of numj~_shift. Then based on the above parameters, the index of cyclic shift pattern {Patternjnd) and the orthogonal cover codes (shiftj) can be derived with reference to that pre-defined cyclic shift hopping pattern stored in the local memory. The calculation of shiftj is the same as in equation (1) and (3) above for intra-TTI hopping and non-hopping UEs. The calculation of Patternjnd can be done in the same way as derivation of shift J^"&s in equation (2) and (4) above for intra-TTI hopping and non-hopping UEs. Then the only change to the above algorithm is to change equations (2) and (4) as follows:

Pattern Jnd_Hop= mod ( iJemp Hop + shiftjjϊop + mod ( floor( impl_resjiop * shift jiiffl numjresjiop ), shift _diff), numj^~_shiftjiop ), (2')

Patternjnd jιoHop= NwnJIop+mod ( iJempjioHop + shiftj jιoHop+ mod ( floor( impl_res_noHop * shift jiiffl nurnjesjioHop ), shift _diff), numJ^"_shiftjιoHop ), (4') [0045] Now is detailed one specific non-limiting example to illustrate implementation.

Figure 3A is an example of the RS structure for a non-hopping structure of the ACK/NACK resource transmitted in PUCCH and Figure 3B is an example of the RS structure for an intra- TTI hopping structure. In these Figures, the number of RSs is assumed to be five in both cases. Note that the RS position is for illustration and need not be exactly as depicted.

[0046] Now, assume the two structures of Figures 3 A-B are multiplexed by allocating six cyclic shifts for intra-TTI hopping and six cyclic shifts for non-hopping (Num_Hop=6), and in each structure shift_diff -2, then the multiplexing capacity of this scheme is 4*3+2*3=18.

[0047] As seen in Figures 3A-B, numJ_shift_Hop=2 and numJ_shift_noHop=4.

Assuming

then according to the above algorithm, the ACK resource (shift_f and shift J) for the 6 UEs with the intra-TTI hopping structure and for the 12 UEs without the hopping structure can be calculated as in the table of Figure 4A.

[0048] Now consider the case of cyclic shift hopping per symbol. Assume the same number of cyclic shifts allocation for intra-TTI hopping and for non-hopping UEs as the example above, and assume there are five RS. The predefined cyclic hopping pattern is assumed to be as in the table below:

Then based on the example algorithm above, the ACK/NACK resource mapping {Pattern_ind and shift J) for the UEs is shown in the table of Figure 4B.

[0049] As will be appreciated, the above embodiments balance the ACK/NACK multiplexing capacity and the ACK/ANCK transmission performance for high speed UEs. Further, a semi-implicit mapping is achieved with little additional signaling overhead.

[0050] Moving to the CQI issue, there are also two transmission schemes for CQI transmitted in PUCCH in TDD. As shown in Figure 5A, the first transmission scheme uses no hopping and an orthogonal cover, and in Figure 5B the second transmissions scheme uses intra-TTI hopping without an orthogonal cover. These two different transmissions are multiplexed by using different cyclic shifts. Based on the UE status measurement (e.g., position, SESTR), the Node B will indicate the transmission pattern to the UE and also the cyclic shift, as detailed above in the solution for ACK/NACK signaling. Note that the RS position is just for illustration in Figures 5A-B.

[0051] Based on the measurement on the UL SINR and the UE's speed, the Node B will determine the transmission scheme for CQI to be reported by the UE. The indication of which transmission will in one embodiment require at minimum one signaling bit, which may be sent from the Node B to the UE via RRC or in the UL scheduling grant.

[0052] The indication of orthogonal cover is not needed for the second transmission scheme, and also is not necessarily required for the first scheme either. It can be omitted by an implicit indication, e.g, the UE can determine the orthogonal cover index based on the control channel index by a formula locally stored in its memory, such as: Orthogonal cover index= control channel index Mod 4. Other implicit determinations are readily derivable.

[0053] The advantages are that CQI transmission performance for both high speed and low speed UEs may be satisfied, and only slight control signaling overhead is added (a one bit indication of the transmission scheme to be used).

[0054] Figure 6 shows a plot of BLER versus SNR (dB) for various combinations of intra-hop and spreading at different UE speeds (3 and 350 km/hr) for a five bit CQI indication sent in one resource block. Clearly at slower speeds the best performance uses no hopping and spreading, whereas the opposite is true at high speeds where the best performance is achieved with intra-TTI hopping and no spreading.

[0055] While described in the context of UTRAN-LTE, it is within the scope of the exemplary embodiments of this invention to use the above described UE 10 and Node-B 12 procedures for other types of wireless networks and the teachings herein are not limited to a particular wireless communication protocol.

[0056] It will be appreciated that embodiments of this invention provide, as generally detailed at Figure 7, a method, a device, a computer readable memory tangibly embodying a computer program that is executable by a processor, and/or an integrated circuit that operates to determine a speed of a user equipment (block 701 of Figure 7), and to signal the user equipment based on the determined speed to use a first or a second transmission scheme for its data non-associated uplink control transmissions (block 702 of Figure 7), where the first transmission scheme uses intra-transmission time interval hopping of reference signals and the second transmission scheme does not. In a particular embodiment, the first transmission scheme is for higher speed UEs and also there is a different cyclic shift among the two different transmission schemes. In another embodiment, the second transmission scheme uses an orthogonal cover code and the first transmission scheme does not. Further, where a Node B practices this aspect of the invention, the Node B maps the non-data associated uplink transmissions received from those UEs using the first transmission scheme to related control channel indices (block 705 of Figure 7), and separately maps the data non-associated uplink control transmissions received from those UEs using the second transmission scheme to related control channel indices (block 706 of Figure 7), where the data non-associated uplink control transmissions are ACK/NACK messages each in one PRB. In a particular embodiment, the Node B signals the user equipment to use the first transmission scheme with a first indication to hop and a second indication as to how many cyclic shifts to use for hopping (detail at block 702 of Figure 7). Further according to exemplary embodiments, a particular user equipment receives the indication(s) from the Node B (block 703 of Figure 7) and transmits its data non-associated control messages on a control channel according to the first or second transmission scheme and the received indication(s) (block 704 of Figure 7).

[0057] In general, the various embodiments may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the invention is not limited thereto. While various aspects of the invention may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

[0058] Embodiments of the inventions may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate.

[0059] Programs, such as those provided by Synopsys, Inc. of Mountain View, California and Cadence Design, of San Jose, California automatically route conductors and locate components on a semiconductor chip using well established rules of design as well as libraries of pre-stored design modules. Once the design for a semiconductor circuit has been completed, the resultant design, in a standardized electronic format (e.g., Opus, GDSII, or the like) may be transmitted to a semiconductor fabrication facility or "fab" for fabrication.

[0060] Various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications of the teachings of this invention will still fall within the scope of the non-limiting embodiments of this invention.

[0061 ] Furthermore, some of the features of the various non-limiting embodiments of this invention may be used to advantage without the corresponding use of other features. As such, the foregoing description should be considered as merely illustrative of the principles, teachings and exemplary embodiments of this invention, and not in limitation thereof.

Claims

CLAIMS:

We claim:

1. A method comprising: determining a speed of a user equipment; selecting a first transmission scheme or a second transmission scheme for the user equipment based on the determined speed, where the first transmission scheme uses intra- transmission time interval hopping of reference signals and the second transmission scheme uses no intra-transmission time interval hopping of reference signals; and signaling the user equipment an indication of the selected transmission scheme for a data non-associated uplink control transmission.

2. The method of claim 1, wherein the data non-associated uplink control transmission comprises at least one of an acknowledgement and a negative acknowledgement and a channel quality indication.

3. The method of claim 1 , wherein the first and second transmission schemes exhibit a different cyclic shift from one another.

4. The method of claim 1 , wherein the second transmission scheme uses an orthogonal cover code and the first transmission scheme uses no orthogonal cover code.

5. The method of claim 1 , further comprising: receiving from the user equipment a data non-associated uplink control transmission using the first transmission scheme; and mapping the received data non-associated uplink control transmission to a control channel index.

6. The method of claim 5, wherein mapping the received data non-associated uplink control transmission to a control channel index comprises calculating only those user equipments that have been signaled the same first indication in a scheduling grant.

7. The method of claim 5, wherein the indication of the selected transmission scheme comprises a first indicator that indicates whether or not to use intra-transmission time interval hopping of reference signals, and wherein the signaling further comprises signaling the user equipment a second indicator that indicates how many cyclic shifts to use for the intra-transmission time interval hopping of reference signals.

8. The method of claim 7, the method further comprising separating, by the second indicator, scheduling grants for a first set of user equipments from scheduling grants for a second set of user equipments, wherein the first indication for each user equipment of the first set of user equipments indicates to use intra-transmission time interval hopping of reference signals, and the first indication for each user equipment of the second set of user equipments indicates not to use intra-transmission time interval hopping of reference signals.

9. The method of claim 8, executed by a node B operating in an evolved universal mobile telecommunications radio access network that sends each of the first indicator and the second indicator semi-statically to the user equipments.

10. A memory storing computer-readable instructions executable by a processor for performing actions directed to determining a first or second transmission scheme for a user equipment, the actions comprising: determining a speed of a user equipment; selecting a first transmission scheme or a second transmission scheme for the user equipment based on the determined speed, where the first transmission scheme uses intra- transmission time interval hopping of reference signals and the second transmission scheme uses no intra-transmission time interval hopping of reference signals; and signaling the user equipment an indication of the selected transmission scheme for a data non-associated uplink control transmission.

11. An apparatus comprising: one of a processor configured to determine a speed of a user equipment and a receiver to receive from a user equipment a speed of the user equipment; the processor further configured to select a first transmission scheme or a second transmission scheme for the user equipment based on the user equipment speed, where the first transmission scheme uses intra-transmission time interval hopping of reference signals and the second transmission scheme uses no intra-transmission time interval hopping of reference signals; and a transmitter configured to signal the user equipment an indication of the selected transmission scheme for data non-associated uplink control transmissions.

12. The apparatus of claim 11, wherein the data non-associated uplink control transmission comprises at least one of an acknowledgement and a negative acknowledgement and a channel quality indication.

13. The apparatus of claim 11 , wherein the first and second transmission schemes exhibit a different cyclic shift from one another.

14. The apparatus of claim 11 , wherein the second transmission scheme uses an orthogonal cover code and the first transmission scheme uses no orthogonal cover code.

15. The apparatus of claim 11 , wherein: he receiver is configured to receive from the user equipment a data non-associated uplink control transmission using the first transmission scheme; and the processor is configured to map the received data non-associated uplink control transmission to a control channel index.

16 The apparatus of claim 15, wherein the processor is configured to map the received data non-associated uplink control transmission to a control channel index by calculating only those user equipments that have been signaled by the transmitter the same first indication in a scheduling grant.

17. The apparatus of claim 15, wherein the indication of the selected transmission scheme comprises a first indicator that indicates whether or not to use intra-transmission time interval hopping of reference signals, and wherein the transmitter is further configured to signal the user equipment a second indicator that indicates how many cyclic shifts to use for the intra-transmission time interval hopping of reference signals.

18. The apparatus of claim 17, wherein the transmitter is further configured to send scheduling grants to a first set of user equipments and to a second set of user equipments that are separated by the second indicator, wherein the first indication for each user equipment of the first set of user equipments indicates to use intra-transmission time interval hopping of reference signals, and the first indication for each user equipment of the second set of user equipments indicates not to use intra-transmission time interval hopping of reference signals.

19. The apparatus of claim 18, wherein the apparatus comprises a node B operating in an evolved universal mobile telecommunications radio access network.

20. A method comprising: receiving an indication whether to use a first transmission scheme or a second transmission scheme for data-non-associated control signaling, where the first transmission scheme uses intra-transmission time interval hopping of reference signals and the second transmission scheme uses no intra-transmission time interval hopping of reference signals; and sending a data non-associated control message on an uplink control channel using the first or second transmission scheme according to the received indication.

21. The method of claim 20, wherein the first and second transmission schemes exhibit a different cyclic shift from one another.

22. The method of claim 20, wherein the second transmission scheme uses an orthogonal cover code and the first transmission scheme uses no orthogonal cover code.

23. The method of claim 20, wherein the indication whether to use the first transmission scheme or the second transmission scheme comprises a first indicator that indicates whether or not to use intra-transmission time interval hopping of reference signals, the method further comprising receiving a second indicator that indicates how many cyclic shifts to use for the intra-transmission time interval hopping of reference signals.

24. The method of claim 20, executed by a user equipment in an evolved universal mobile telecommunications radio access network.

25. A memory storing computer-readable instructions executable by a processor for performing actions directed to determining a first or second transmission scheme for a transmission, the actions comprising: receiving an indication whether to use a first transmission scheme or a second transmission scheme for data-non-associated control signaling, where the first transmission scheme uses intra-transmission time interval hopping of reference signals and the second transmission scheme uses no intra-transmission time interval hopping of reference signals; and sending a data non-associated control message on an uplink control channel using the first or second transmission scheme according to the received indication.

26. An apparatus comprising: a receiver configured to receive an indication whether to use a first transmission scheme or a second transmission scheme for data-non-associated control signaling, where the first transmission scheme uses intra-transmission time interval hopping of reference signals and the second transmission scheme uses no intra-transmission time interval hopping of reference signals; and a transmitter configured to send a data non-associated control message on an uplink control channel using the first or second transmission scheme according to the received indication.

28. The apparatus of claim 26, wherein the first and second transmission schemes exhibit a different cyclic shift from one another.

29. The apparatus of claim 26, wherein the second transmission scheme uses an orthogonal cover code and the first transmission scheme uses no orthogonal cover code.

30. The apparatus of claim 26, wherein the indication whether to use the first transmission scheme or the second transmission scheme comprises a first indicator that indicates whether or not to use intra-transmission time interval hopping of reference signals, the receiver further configured to receive a second indicator that indicates how many cyclic shifts to use for the intra-transmission time interval hopping of reference signals.

31. An apparatus comprising: processing means for determining from a received indication whether to use a first transmission scheme or a second transmission scheme for data-non-associated control signaling, where the first transmission scheme uses intra-transmission time interval hopping of reference signals and the second transmission scheme uses no intra- transmission time interval hopping of reference signals; and sending means for sending a data non-associated control message on an uplink control channel using the first or second transmission scheme according to the received indication.

32. The apparatus of claim 31 , wherein the first and second transmission schemes exhibit a different cyclic shift from one another.

33. The apparatus of claim 31 , wherein the second transmission scheme uses an orthogonal cover code and the first transmission scheme uses no orthogonal cover code.

34. The apparatus of claim 31 , wherein the indication whether to use the first transmission scheme or the second transmission scheme comprises a first indicator that indicates whether or not to use intra-transmission time interval hopping of reference signals, the processing means further for determining from a second received indicator how many cyclic shifts to use for the intra-transmission time interval hopping of reference signals.