SYSTEM: AND METHOD FOR

ALLOCATING' TRANSMISSION RESOURCES

This application claims the benefit of U.S. Provisional Application No, 61/332,86?, filed May 10, 2010, entitled "Uplink Code ord-to-Layer Mapping for Improved Separation of UCI and Data," which is incorporated by reference in its entirety,

TECHNICAL FIELD OF THE INVENTION

This disclosure relates in general to wireless eomimimcation and, more particularly, to resource allocation for nuuti -antenna transmissions.

BACKGROUND OF TEE INVENTION.

Multi-antenna transmission techniques can signifi ntl increase the data rates and reliability of wireless communication systems, especially in systems where the transmitter and the receiver arc both equipped with multiple antennas to permit the use of multiple-input multiple-output (M! O) transnussion techniques. Advanced communication standards such as Long Term .Evolution (LTE) Advanced utilise Μ.ΪΜ0 transmission techniques that may permit data, to be transmitted over multiple different spatially-multiplexed channels simultaneously, thereby significantly increasing data throughput.

While Ml MO transmission techniques can significantly increase throughput _* such techniques can greatly increase the complexity of managing radio channels. Additionally, many advanced communication technologies, such as LIB, rely on a substantial amount of control signaling to optimize the co figuration of transmitting devices and their use of the shared radio channel. Because of the increased amount of control signaling in advanced communication technologies, it is often necessary for user data and control signaling to share transmission resources. For example, in LTE systems, control signaling and user data are, in certain situations, multiplexed by user equipment CUE") or transmission over a physical uplink shared channel ("PUSCH").

However, conventional solutions for allocating transmission resources are designed for use with single layer transmission schemes in which only a single codeword, of user data is transmitted at a time. As a result, such resource allocation sol tions to provide optimal allocatio of transmission resources between control information and user data when MIMO techniques are being utilized to transmit data on multiple layers simultaneously. SUMMARY OF TUB INVENTION

In accordance with the present disclosure, certain disad anta es and problems associated with wireless communication have been substantially r duced or eliminated. l:o particular, certain devices and techniques for allocating transmission resources between control ln.f .rt«ado» and user data a e described.

In accordance with one embodiment of the present disclosure, a method for wirelessSy transmitting user data and at least a. first type of control information using a plurality of transmission layers including encoding hits of a first type of control information to form one or more control codewords and encoding bits of user data to form one or more user data codewords. The method also includes generating a plurality of vector symbols based on the control codewords and the use data codewords. Each vector symbol includes a plurality of modulation symbols that are each associated with a transmission layer over which the associated modulation symbol will be transmitted. Generating the plurality of vector symbols includes interleaving bits of the one or more control codewords and bits of the one or more user data codewords so that the first type of control information is carried in modulation symbols associated with the same transmission layers in all the vector symbols transmitted dining the subframe that carry the first type of control information. The method also includes transmitting the piuraiity of vector symbols to a receiver over a plurality of transmission layers.

Additional embodiments include apparatuses capable of implementing the above method and/or variations thereof.

Important technical advantage of certain embodiments of the present Invention include increasing the benefits gained from transmission diversity and simplifying processing of multi-antenna transmissions. Particular embodiments enable control information and user data to be divided into separate vector symbols so that control and data are time multiplexed, as opposed to being transmitted in parallel. In particular embodiments, this separation may be attained without incurring significant additional control overhead and may enable reuse of conventional uplink processing modules. Other advantages of the present invention will be readil apparent to one skilled in the art -from the following figures, descriptions, and claims. Moreover, while specific a vantages have beea enamsrated above, various embod$me»s ma iac! de ail some, or none vf the enumerated advantages.

BRIEF DESCRIPTION OF Till DRAWINGS

For a more com le e understanding of the present invention and Its advanta es, reference is now made to the following description, taken In conjunction with the accompanying drawings, in which;

FIGURE .1 is a functional block diagram illustrating a particular embodiment of a multi-antenna transmitter;

FIGURE 2 is a functional block diagram, illustrating a particular embodiment of a carder modulator that may be used in the transmitter of F IG URE i;

FIGURE 3 is a transmission resource grid for an example subfratne in a wireless communication system;

FIGURES 4A- C provide further detail* on specific portions a particular embodiment of the transmitter;

FIGURES SA-SC also provide further details on specific portions a particular embodiment of the transmitter;

FIG URE 6 is a functional block diagram illustrating an alternative embodiment of the transmi ter;

FIGURE ? is a functional block diagram providing further details on a. channel encoder utilised by the embodiment shown in FIGURE 6;

FIGURES 8A and SB illustrate operation of various embodiments of the transmitter in transmitting example control information and user data;

FIGURE 9 is a structural block diagram showing the contents of an example mbodim nt of the transmitter; and

FKJURE 10 is a flowchart illustrating example operation of a particular embodiment of the transmitter. DETAILED DESCRIPTION OF TEE INVENTION

FIGURE I is a functional block diagram illustrating a particular embodiment of a maltl~a»tenna transmitter 100. In particular, FIGURE I. shows a transmitter 100 configured to multiplex certain control signaling with user data for transmission over a single radio channel. By .intelligently implementing the coding, interleaving, layer mapping, and other aspects of the transmission, transmitter 100 may be able to improve upon the resulting allocation of user data and control, signaling to transmission resources, as described further below.

Control signaling can have a critical impact on the performance of wireless co manieation systems. As used h rnia, "control signaling" and ''control information'* refers to any information c mmunicated between, components for purposes of establishing communication, any parameters to be used by one or both, of the components in communicating with one another ( g, , parameters relating to modulation, encoding schemes, antenna configurations), any information indicating receipt or non-receipt of transmissions, and/or any other form of control. information. In LTE systems, control signaling in the uplink direction includes, for example, Hybrid Automatic Repeat reQuest (f ARQ) Acknowledgments/Negative Acknowledgements (ACK/NAKs), precoder matrix indicators (PMIs), rank indicators (RIs), and channel quality indicators (CQIsk which are all used by the e ^' odeB to get confirmation of successful reception of transport blocks or to improve the performance of downlink tran s i ss ion ,

Although control signaling is often transmitted on separate control channels _* such as the physical uplink control channel (PUCCH) in. LTE, under certain circumstances it may be beneficial or necessary to transmit control signaling on the same channel as other data. For example, in LTE systems, when a periodic PUCCH allocation coincides with a scheduling grant for a user equipment (U.E) to transmit user data, the user data and control signaling share transmission resources to preserve the single-carrier property of the discrete Fourier transform, spread orthogonal frequency- division multiplexing (0PTS-OFDM) transmission techniques used by LTE UBs. Furthermore, when a OB receives a scheduling grant to transmit data on the physical uplink shared channel (POSCH), it typically receives information from the e odeB related to the characteristics of the uplink radio propagation channel and other parameters that can be used to improve the efficiency of FUSCH transmissions. Such information may Include modulation and coding scheme (MCS) indicators as well as, for UEs capable of using multiple transmission, antennas, M Is or Rls. As a result, UEs may be able to use this information to timize POSCB transmissions for the radio ehauuel, thereby increasing the amount of data that can be transmitted tor a given set of transmission resources. T u , by multiplexing control signaling with the user data transmitted on PUSCIT a UB can support significantly larger control payioads that) when transmitting contr l signaling by itself ot) PUCCH.

In such circumstances, it ma be possible for transmitter 100 to multiplex control signaling and user data in the same maimer as is proposed by Release 8 of the LTE standard. Under such a scheme, some or all control signals are distributed onto multiple codewords (e,g,, by repetition or by a serial o«parai lei conversion) and each codeword is then processed individually. After symbol modulation, the two sequences of modulated symbols are mapped onto their assigned layers to f rm a sequence of vector symbols. As used herein, a "vecto symbol ^** may represent any collection of information thai includes an information element associated with each transmission layer o er which the inf rm i n is to be transmitted. The vector symbols arc then modulated onto appropriate carriers and transmitted.,

However, using thi technique to allocate transmission resources ( .g., vector symbols) to particular elements of user data or control information, can make it difficult to separate control information from user data so that the two types of information are mapped onto separate vector symbols. Separation of this sort, may be desirable tor certain types of control information > Th difficulty in doing ibis is primarily due to the kterleavers used by most conventional devices to map modulation symbols into a subframe resource grid, such as the example grid shown in FIGURE 3, In Release 8 LIE user equipment (UB), the iaterleaver maps modulation symbols of concatenated CQi/F t and data codewords into the suhh nne resource grid in a row first, and column next order, However, the carrier modulator for such UEs reads OPTS -OFDM symbols out of the interleave* in a column first fashion, making it difficult to determine what the resulting allocation of control and user data will be.

Furthermore, if a particular user data codeword is mapped to, e.g., two layers, then, the part of the control codeword to be multiplexed, with the data codeword must cover a multiple of two entire rows in the resource grid. Otherwise, there will be columns in the grids that have an odd number of modulation symbols carrying control information, I» which ease user data and control will be mixed in a single vector symbol. This can cause significantly more overhead to be used for transmissions of control Information since LTE Release 8 permits a control codeword to use any fraction of a row in the transmission resource grid to reduce overhead. Reconfiguring the Release scheme to remove the above constraint o control resource allocation would involve significant redesign of either th channel interieaver or the multiplexing unit specified by Release 8.. Additionally, it would create significant inter-dependencies between the layer mapping and tire components responsible for processing the user data and control information. Such interdependenctes can result in complex implementations and ma significantly complicate backwards compatibility.

As a rests It certain embodiments of transmitter 100 may be configured to allocate a given type of control information to the same, specific elements of the vector symbols that carry that type of control information. For example, a particular type of control information may be allocated to the elements associated with the first layer and second layer in all the vector sy mbols that carry that type of control, information. Thus, in such embodiments, a given type of control information may foe mapped to the same layers in all vector symbols that are used to transmit the relevant control information. Furthermore, particular embodiments of transmitter 100 isolate all or some (e.g., certain types) of the control signaling transmitted during a particular subframe on separate vector symbols, with the relevant, control information being transmitted, on vector symbols that do not carry any user data., As a result, the relevant control, signaling will be time multiplexed with the user data transmitted during the same suhirarne, instead of being transmitted in parallel with that user data.

Maintaining a consistent m p i g of control information to the various layers across all the vector symbols carrying the control information may provide numerous advantages depending on the configuration of transmitter 100.. In particular embodiments, maintaining a consistent mapping may increase the diversity benefits provided by the multiple transmission layers, as a given portion of the transmitted control information is more likely to be transmitted on multiple layers simultaneously than with conventional techniques for allocating transmission resources. Moreover, for particular embodiments of transmitter 100, the modulation and encoding sc emes tbr the variotts layers are designed to ensure that the mapping pattern for the rele nt types of control information is the same on all layers used to transmit that control mfomtatiott. This guarantees that a given portion of die control raforraatkn will be transmitted simultaneously on all layers over which it i to be trimsmitted. Additionally, by isolating at least a portion of the control information on separate vecto symbols, transmitter 100 may simplify processing on the receiving end., as tire receiver may be able to perform identical processing on the control information received on every layer. As a result, certain embodiments of transmitter 100 may provide numerous operational benefits. Spe ific embodiments, however, may provide some, none, or ail of these benefits.

As described farther below; the various embodiments ot transmitter 100 may implement the described allocation techniques using any of numerous di iierent structural and/or .functional configurations- FIGURE I illustrates a particular embodiment of transmitter 190 configured to perform the described allocation techniques on a "per-kyer" basis, In particular embodiments, as shown In FIGURE .1 , particular embodiments of transmitter 1.00 ma include one or more layer mappers 104 and one or more bit distributors 106 capable of splitting (by replication and/or by segmentation) the user data and control information to be transmitted onto separate datapaths 102. with each datapath 102 being associated with a particular one of the transmission layer to he used for the transmission. By performing the codeword-to- layer mapping in the bit-level d main prior to control and dat multiplexing, certain embodiments of transmitter 100 configured for per- layer processing may offer the additional benefit of permitting reuse of single stream components responsible for Ore modulation, scrambling, interleaving, encoding, or other processing in single-antenna iranstnitters.

Additionally, in particular embodiments, such as the one illustrated in FIGURE 3 , transmitter 100 may isolate certain types of control information onto separate vector symbols but pmmt other types of control information to be transmitted, on vector symbols that are also carrying user data on other layers. Different types of control information may have different robustness requirements, may utilize different encoding schemes, or may be treated differently during transmission for various other reasons. Consequently, it ma be more beueffcial to isol e certain types of control mfomta&on on separate vector symbols than t is to isolate other types of control inforatattoa. For example, in LIE, Hybrid Automatic Repeat reQuest (MARQ) Ackno ledg ents/r^gative Acknowledgements (AC / A s) and rank indications 5 (RIs) are typically only a few bits m length, and their successful transmission may be critical to system operation. As a result, HARQ ACK/NAKs and RIs may have different encoding requirements and ma require special timing within a subfrarae (e.g., being transmitted near a reference signal in resource grid 400). By contrast, control information such as precedes; matrix indications (PMls) and channel quality indications

It ⁾ (CQIs) ma be of lesser Importance and transmitter 100 may spread these types of control information throughorJt trie su frame.

^' Thus, in the example embodiment illustrated by FIGURE 1 , transmitter 100 implements different processing for different types of control information. For example, in the illustrated example, a first type or types of control information

15 (represented here by ACK/ AI bits 134 and .III bits 136) are input into separate bit distributors to be distributed to me various layers and encoded before being combined with any user data codewords 130 by interleavcr 1 12, Particular embodiments transmitter 100 are configured to ensure that this first type of control information is ultimately allocated to vector symbols 140 that are not also carrying user data. By 0 contrast, a second type or type(s) of control information, (represented here by a CQl codeword 332 containing encoded CQI and/or PM1 information) is concatenated, in the embodiment of FIGURE I , with one or more user data codewords 1 0 by a multiplexer 108 before being interleaved with die other types of control mformaitoft (here, AC / A bits 134 and Rl bits 136). The second type(s) of control information may 5 end up being transmitted in vector symbols 340 that also carry user data.

The embodiment of transmitter 100 illustrated by FIGURE 1 includes one or more layer mappers .104 and one or more bit distributors 106 that associate their inputs with one or more of the various layers for processing, More specifically, layer mappers 104 receive user data codewords 1 0 (In this example, a user data codeword 130a and a 0 user data codeword 130b) and CQl codewords 132 and map bits of these codewords to one of the transmission layers to he used by transmitter 1 0 for the relevant transmission. Bit distributor .lOoa receives nnencoded ACK/NAK bits 134 and replicates the .AC /NAK, ts 134 on each, of the layers o« which control- mfomia&on will be transmitted. In the illustrated example this involves replicating ACK/NA . on all of the layers that will be used, for the transmissioa. Bit distributor 106b receives unencoded Rl bits 136 and replicates the Rl bits 136 on each of the layers on which control kvfomiation will he transmitted. As with the ACK/NAK bits 134, this may invol ve replicating Rl bits 136 on all of the layers that will be used to transmit control infbmiation.

Because the illustrated embodiment of transmitter 100 in FIGURE 1 imp:iet«e.«ts a par-layer processing scheme, each transmission layer available to transmitter 100 is associated with, a separate datapath 102 composing various elements responsible for processing the user data and control information, that will be transmitted over the associated transmission Saver. As a result, bit distributors 106a and 1.06b replicate their input hits for every datapath 102 over which the first iype(s) of control information will be transmitted.. A channel encoder 110a and a channel encoder 1 10b in each datapath 102 then encode the control information output by bit distributors 106a and b. respectively. The encoding performed by die various channel encoders 1 1.0 in transmitter 100 may be the same lor ail of the channel encoders 110 or may differ based on, for example, the transmission layer involved or the type of control information being encoded. Channel encoders 1 10a and 11 b in each datapath 10 then output a control codeword to an interleave 1 2 associated with the same layer as the relevant channel encoders 1 10.

Meanwhile, layer mapper 104a outputs ne or more bits of riser data codeword 130a or user data codeword 1 0b to each, of the datapaths 102 associated with a layer over which the relevant user data codeword 330 will be transmitted. Similarly, layer mapper .104b outputs one or .more bits of a control codeword of a second type of control information (here, CQIs and/or PMls) to each of the datapaths 102 associated with a layer over which this second type of control information will be transmi tted.

In particular embodiments, transmitter 100 may map the second type of control, information t the various layers in a manner designed to facilitate the efficient allocation of user data and control information to transmission resources. As one example, in particular embodiments _* transmitter 100 encodes the second type of control information prior to Its layers. This encoding may be performed with a rate matching such that the length of the resulting control codeword is m even multiple of Q' of

2 ¾ _S ,> here £k,ts the num er of bits of each modulation symbol on layer , and r is the total number of layers that mil be used to transmit the user data codeword ! 30 with which this control codeword will be multiplexed. Thus, the numbe of bits in the

S resul ing control codeword will be e u l to Q' > ζ)„. <

As another example, transmitter 100 may map a number of bits equal to ff -Q^ to each of the layers over which this control codeword (and its multiplexed user data codeword 130} will be transmitted. Additionally, transmitter 100 may, as part of this mapping layers, segment the control codeword into r parts, where r is the 10 number of layers used to transmit this control codeword and where the part assigned to layer i has the length Q'-Q^ bits,

As other example of the mapping that transmitter 100 may use for the second type of control information, transmitter 100 may perform a serial~to~parahel operation of the coded symbols in the control codew ord such, that,

I S or¾*> * e .. ..· . p _¾J ♦ , * ] _t where denotes the k -th bi t (counting from 0) of this control codeword mapped to layer /(counting from 1) and cm, denotes the m ~ih bit (counting from 0) of the control codeword prior to bit-level layer mapping, A benefit of this option is that it guarantees that the same number of modulated symbols is required lor the second type 0 of control mfbrmation on all layers,, which, may pemi.it a design where control information and user data are fully mapped to separate vectors symbols.

Similarly, transmitter 100 may also perform: the codewofcl-to-!ayer mapping of the user data codewords !30a-h in a manner designed to improve the subse uent allocation of user data and control information to transmission resources. As one 5 example, transmitter 100 may perform the codeword-to-layer mapping of user data codewords S 30a-b using a seoal-to-parallel (S/F) operation such that in. each pair of neighboring bits, the f t hit is assigned to one layer and the rest is assigned to the other layer. This option has the benefit that it is simple to implement and that it does not introduce any addi onal delays. As another exam le, the bit-level codeword-io- layer mapping of the data m y include a eodeb!ock segmentati n operation such thai the first half of the codeword Is assign d to one layer and the second half to the oilier layer. This option has the benefit thai it enables advanced per layer successive per- layer interference cancellation at the receiver, since it is likely that there will be entire block segments (including a cyclic redundancy check. (C C)) assigned fully to a single layer.

Once user data codewords 130 and CQI codewords 1 2 have been mapped io various layers to be used by transmitter 100 for the transmission, a multiplexer 108 in each datapath 102 then Multiplexes the bits of user data codewords 130a~h and the bits of the CQI codeword. 132 output to the relevant datapath 102, resulting in. the CQI codeword 132 being concatenated with the user data codewords 130 on one or more layers. The output of each multiplexer 108 is then received by an interleaver 1 12 in the same datapath 102,

Each .interleaver 112 then allocates encoded bits of user data and control information to transmission resources on the layer associated with that interleaver 112. Each interleaver 11 may map user data and control infomtatton to a res urce grid such as the example resource grid Illustrated by FIGURE 3. Int rle ves 11 associated with the various datapaths 102 in transmitter 100 may perform this interleaving in any suitable manner, in the embodiment shown by FIGURE I, transmitter 100 uses a per- layer processing scheme to transmit user data and control information. As a result, the illustrated embodiment may use conventional interleaving techniques on each layer, including interleaving techniques that might also he used in. single antenna transmissions.

For example, particular embodiments of transmitter KM) may implement the channel interleaving specified by LIE Release S for each layer. LIE Release 8 interleaving utilizes a matrix of coded symbols (groups of Q _m bits, where Q _m is the number of hits forming a modulation symbol). Each column in this matrix corresponds to a DFTS-OFDM: symbol. Under LTE Release 8 interleaving, the coded symbols (groups of hits) of the Rl codeword are inserted in the assigned positions (as indicated in the example resource grid of FIGURE 3). Next, the concatenated CQI / user data codewords (resulting from the nmltipl.ex.ing of CQ codewords 132 and user data codewords 130) are inserted a o nd th I codeword m a row-first order. Then, coded s m ls of HAEQ codeword (groups of Q _m hits) on a particular laye are inserted hi the assigned positions shown in FIGURE 3, puncturing the user data and potentially the CQI information,

Additionally, as explained above, the interleaves J 1.2 for the various layers used by transmitter 100 may allocate user data and control information in such a manne that some or all. of the control information may be allocated, to separate vector symbols 1 0 that do not carry any user d . Because the illustrated embodiment in FIGURE 1 uses a per- layer technique for processing user data and control .information to be transmitted, the various interleaves ! 12 in the transmitter of FIGURE 1 may achieve this separation hi part by performing similar or identical interleaving on each of the layers used tor a transmission. furthermore, particular emb diments of transmitter 100 may also utilize the same modulation scheme on all layers for a given type of data, resulting in an identical mapping of control infor ation and user data to transmission resources on ever layer.

Once interleaving has been performed, the output of the channel interleave!' on each layer is read out of the interleaving matrix a column at a time. These interleaved outputs are then scrambled by scramblers 1 14 in each datapath 102 and subsequently modulated by symbol modulators 1 16, In particular embodiments, the scrambling sequences performed fey the respective scramblers 1 14 on each of the layers is initialised using a different seed. For example, scramblers 1 14 may scramble the output of th interleave* on their respective layer by perform the scrambling operation defined in § 5.3.1 of OTP TS 36.21 1 V9. I .G, "E-UTRA, Physical Channels and Modulation" (which is herein incorporated by reference in its entirety) but with a layer- specific scrambling sequence, such as a layer-specific generator seed ^™ c _im (q) for a layer q . Furthermore,, in particular embodiments, scramblers 1 14 use a layer-specific scrambling sequence seed c _ms defined by the following equation;

where q is the layer associated with the sequence seed, ti _r - is a radio network temporary identifier for transmitter 1.00, n _x is a slot number within a radio frame, and is a cell Identifier associated with a ceil in which vector symbols 1.40 are to be transmitted.

After s mbol modulators .1 .16 for each of the layers generate modulation symbols from the output of their corresponding scramblers 1 14, a set of modulation symbols from each of the datapaths 102 are collectively input into carrier modulator 1 1 S as one or more vector symbols 140. Carrier modulator 1 1 S modulates information from vector symbols 140 onto a plurality of radiofrecniency (RF) snbearrier signals.. Depending on the communication technologies supported by transmitter 100, carrier modulator MS may also process the vector symbols 140 to prepare them for transmiss on, such as by preceding vector symbols J.40. The operation of an example embodiment of carrier modulator 1 18 for I..TE implementations is described in greater detail below with respect to FIGURE 2, After any appropriate processing, carrier modulator .1 .18 then transmits the modulated suhearriers over a plurality of transmission antennas 120.

As explained above, if each of the channel mterleavers 1 .12 in the various datapaths 102 are configured to interleave input bits in the same manner (e.g., reading in bits in a row-bv~colan«¾ manner and reading out bits in a column-by-ro manner ;. control information, of the first type(s) will be outpu an vector symbols 140 that contain only that type of control information and do not include any user data. For the illustrated example, this means that bits from ACK/NAK codewords and Rl codewords are carried by vector symbols 1 0 that do not contain any user data. By contrast control information of the second iype(s) will be mixed with user data in the vector symbols 140 output to carrier modulator 118.. Fo the illustrated example, this means that bits from CQI codewords 132 are carried by vector symbols 1 0 that may also carr bits of user data on other layers.

Thus, by interleaving control information and user data such that vector symbols 140 carrying certain types of control information do not include an other type of data, transmitter 100 may improve transmit diversity gains achieved by the multi- antenna transmissions made by transmitter 100. Transmitter 100 may also reduce computational complexity in the processing performed both by transmitter .1 0 itself or by devices that receive the information transmitted by transmitter 100. Additionally, although the description herein focuses on implementation of the described resource allocation techniques in wireless comm.u»ica»o» networks supporting WE, the described resource allocation techniques may be utilised in conjunction xvith any appropriate communication technologies including, but not limited to LIE, High-Speed Packet Access plus (HSPA^ and Worldwide Interoperability for Microwave Access (W ^' iMAX),

FIGURE 2 is a functional block diagram showing n greater detail the operation of a particular embodiment of earner modulator VIS. In particular, FIGURE 2 illustrates an embodiment of carrier modulator 1. 18 that might be used by an embodiment of traiismitter .100 that utilizes DFTS-OFDM as required for uplink ansmiss ns in LTE. Alternative er»bodh«ents may be configured to support any other appropriate t e of carrier modulation. The illustrated embodiment of carrier modulator I I B includes a OFT 202, a precoder 204, an inverse OFT (IDFT) 206, and a plurality of power ampli iers (PAs) 208.

Carrier modulator 1 18 receives vector symbols 1 0 output by layer mapper .1 10. As received by carrier modulator VI S, vector symbols 140 represent time domain quantities. DPT 202 maps vector symbols 140 to the frequency domain. The frequency-domain version of vector symbols 140 are the linearl preceded by precoder 20 using a preceding matrix, W, that is (N _T x r ) in siz , where N _T represents the number of transmission antennas 120 to be used by transmitter 100 and t represents the number of transmission layers that will be used by transmitter 1 0. This precoder matrix combines and maps the r information streams ontoAV precoded streams. Precoder 204 then generates a set of frequency-domain transmission, vectors by mapping these precoded frequency-domain symbols onto a set of sub-carriers that have been allocated to the transmission.

The frequency-domain transmission vectors are then converted back to the time domain by IDFT 206.. In particular embodiments, IDF 206 also applies a cyclic prefi (CP) to the resulting time-domain transmission vectors. The time-domain transmission vectors are then amplified by power amplifiers 208 and output from carrier modulator 1 18 to antennas 120, which are used by transmitter 100 to transmit the time-domain transmission vectors over a radio channel to a receiver.

As explained above, the described allocation techniques can be implemented in a variety of different ways fey different embodiments of transmitter 100. FIGURES 4A-8B illustrate in ea er detail the functionality of various em od m nts of transmitter 100 that axe capable of implementing the described allocation techniques.

FIGURES 4A-4C and 5.A-5C illustrate one variation on a particular portion of transmitter 100. Specifically, FIGURE 4Λ shows an embodiment f transmitter 100 that includes an expanded view of layer mapper 104b responsible for mapping codewords of the second type of control information (again, CQI codewords 132 for purposes of the example in FIGURE I) to die various transmission layers. In this expanded view, layer mapper 104b includes a controi-to-data distributor 402 and a code word-to- layer tapper 404. J.n the illustrated mbodi en , the eodeword-to-layer mapp r 404 is identical to the layer mapper 104a .for user data codewords 130. in this embodiment of transmitter 100, control-to-data distributor 402 distributes bits of CQI codewords 132 onto a number of sets of bits, each set associated with a user data codeword 130 (although some of these sets may be empty). Codeword-to-layer mapper 404 then maps the various portions of the CQI codeword .132 to different transmission layers based on the user data codeword 130 thai the relevant portion of the CQI codeword .132 has been assigned to.

FIGURE 4B shows ex m le operation tor a particular portion of transmitter 100 that is configured as shown by FIGURE 4A. In the illustrated example, codeword-to- layer mapper 10 receives two user data codewords !30a-h and eomroi-to-data distributor 402 distributes a single CQI codeword 132 between the two user data codewords !30a-b. Layer mapper 104a and codeword-to-layer mapper 404 then map user data codewords !30a.-b and the distributed CQI codeword 132. respectively, to associated transmission layers, as shown by FIGURE 4B.

FIGURE 4C llustrates a related embodiment of transmitter 100 in which eonirol o~daia distributor 402 utilizes a specific distribution function. In particular, FIGURE 4€ illustrates an embodiment in which con rohcodeword™to--data-crideword distributor 402 maps the relevant. CQI codeword 132 to only one of die two user data codewords 130 to be transmitted.

Alternative embodiments of transmitter 100 may produce identical output using other configurations of the codeword»to«layer mapper 104 and the multiplexer 108.. For example, FIGURE 5A shows another embodiment of the same portion of transmitter .100 in which the codeword-to- layer mapper 104 is moved behind the multiplexer 108 k the relevant datapath 102. Despite this modification, the combinati n of components can he configured to produce the sam output as the embodiment illustrated by FIGURE 4A, as shown by the operating example of FIGURE 5B. Similarly, FIGURE 5C illustrates another conftg ation of the same portion of transmitter J 00. As with 5 FIGURE 4C _» FIGURE 5C Illustrates a specific example of FIGURE 5A in which eonirol o*dat distributor 402 maps CQ! codeword 132 onto only one of the two user data codewords 30 to be transmitted. Thus, as FIGURES 4A-4C and FIGURES 5A~ 5C show, transmitter too can he configured to operate in the same manner regardless of whether layer mapping occurs before or after the user data and control multiplexing

It ⁾ performed by multiplexer 108.

Additionally, as a variation on. the per-tayer embodiment of transmitter 100 that is illustrated by FIGURE U particular embodiments of transmitter 1 0 may be capable of performing "per-codeword" processing of input user data codewords 130 under which a separate datapath 602 is associated with each user data codeword 130 to be

1.5 transmitted as opposed to each transmission layer to be used.

FIGURE 6 illustrates an alternative embodiment of transmitter 100 in which the allocation techniques described above are implemented by modifying conventional interleaving and channel encoding methods, FIGURE 6 shows such an embodiment of transmitter 100. Specifically, the embodiment illustrated by FIGURE 6 includes an 0 extended channel interieaver 612 and an extended channel encoder 610 that pe brra modifled versions of the interleaving and channel coding performed by, for example, LTE Release 8 user equipment when transmitting multiplexed user ata and control inlbmiation on the PIJSCM.

In particular embodiments, extended channel encoder 61.0 performs 5 conventional channel coding to unencoded bits of a first type(s) of control information.

For the example of FIGURE 6, these types of control information again include Rl information and KARQ feedback information. In addition to this channel encoding, extended channel encoder 610 may also perform additional operations to facilitate the use of the allocation techniques described above. In particular embodiments,, this may 0 involve replicating encoded bits of the control information to match the number of copies of each encoded bit to the number of layers that will be to transmit the relevant codeword. For example, FIGU 7 illustrates in greater detail a particular embodiment of extended hannel encoder 610, As shown by FIGURE 7, the illustrated, erabodiraeut of extended channel encoder 610 Includes a channel encoder 620 which may operate similarly or identically to channel encoder 110 of FIGURE !, Additionally, the illustrated embodiment of extended channel encoder 610 includes a layer replicator 622, Layer replicator 622 receives an input sequence of encoded control information bits and repeats each bit of the sequence once for every layer on which the codeword associated with the relevant datapath will be transmitted. Thus, as shown in FIGURE ? _:! for an example input bit sequence of » _{8 s} , channel encoder 620 encodes the input bits to generate an encoded bit sequence,*/ ■ Depending on the number of layers that will be used to transmit the user data codeword 130 associated with the relevant layer replicator 2 , layer replicator 622 may replicate individual bits of the encoded sequence so that the resulting replicated hit sequence includes multiple copies of each bit in the encoded sequence. Specifically, the replicated bit sequence includes a number of copies of each encoded bit equal to the number of layers that will he used to transmit the user data control word 130 associated with this datapath 102. The example extended channel encoder 610 shown in FIGURE 7 is assumed to be associated with a user data codeword 130 that will be transmitted on two transmission layers. Thus, layer replicator 622 replicates each hit of the encoded bit sequence ( ^ ₍ ) once so that the replicated bit sequence includes two copies of each encoded hit ( _;; g _{<i (} g ),

Returning to FIGURE 6, the illustrated embodiment of transmitter 100 combines the modified channel coding provided by extended channel encoder 610 with a modified interleaving technique provided by extended channel inter leaver 612. As with extended channel encoder 6I0, extended channel inierieaver 612 performs a version o a conventional interleaving technique (e.g., the interleaving specified by LIE Release 8) that has been modified to implement Ore allocation techniques described above with respect to FIGURE 1. More specifically, a conventional interieaver implementing the interleaving specified by LTE Release 8 utilizes a matrix of coded symbols I groups o Q _m bits, where O _ifi is the number of hits forming a modulation symbol). Each column in this matrix corresponds to a DF ^' FS-OFDM symbol. Under LTE Release 8 Interleaving, the coded symbols (groups of Q bits} of me M codeword are inserted in ie assi ned positions (as indicated in the example resource grid of FIGURE 4). Nest, the concatenated CQi / user data codewords (resulting from the multiplexing of CQI codewords 132 and user data codewords 130) are inserted around ie RJ codeword in a row-first order. Then, coded, symbols of ACKJ AK codeword (groups of Q _m bits) are inserted in the assigned positions shown in FIGURE 4, puncturing the user data and potentially the CQI information

In particular embodiments, the Release 8 interleaving scheme is modified for use by extended channel interieaver 612 such that each column in the interieaver matrix represents the DFTS-OFDM symbols that are to be transmitted in parallel on the layers associated with the corresponding user data codeword 130. Moreover, the particular interleaving pa tem implemented by extended channel interieaver 612 under this extended interleaving scheme depends on the number of layers a particular control or user data codeword is mapped onto. f a codeword is mapped to I layers, then every i coded symbol (group of Q _m bits) in a column is associated with the same layer, That is, the coded symbols of the different layers are interlaced. Additionally, the interleave! ^' matrix is filled in groups of -Q^ coded bits (contrary to the conventional interleave? that is filled in groups of Q _m bits). The ro ping of coded bits ensures time-alignment between the layers associated with a particular codeword, in. a similar or identical fashion to that described above with respect to the embodiment of FIGURE I .

When the interleaving of extended channel interleave* 612 is combined with the replication of coded symbols of a first type or types of control information (HARQ and RI information in this example) thai is performed by extended channel encoder 610, the coded symbols of the first rype(s) of control information will be repented on all layers of the resulting vector symbols 140 carrying the first, type of control information. ^" Ours, the first type(e) of control information will fee isolated on separate vector symbols 140 from the user data, with the relevant control information being transmitted on vector symbols 140 that do not carry any user data..

Consequently, with the extensions to the conventional interleaving and channel encoding operations described above, the pen-codeword processing embodiment of transmitter 100 shown in FIGURE 7 is capable of implementing the same allocation techniques described above with respect to the pre« layer embodiment shown in FIGURE I . Moreover, If the sc amb ing operations of the per-iayer and he per- codeword embodiment are selected appropriatel the output of the two embodiments may be identical on a oit~by~feft level For example, if two sequences axe used for the per-eode ord processing (one for each codeword), then the per ayer processing fommlation can be implemented with the scrambling sequences split onto the two associated layers such that every other group of O _r i s mapped to every other associated layer. Conversely,, if four separate sequences are used for the per-layer processing, the two associated with a single codeword can be interlaced in groups of bits to fi m a per-codeword scrambling sequence, for each of these cases, the output of the per- ayer embodlmeui and the pet-codeword embodiment ( w ith extended interleaver and channel coders) will be identical.

FIGURES SA and SB provide an example demonstrating this point. FIGURE 8A illustrates FUSCH signaling and UCl multiplexing for a per-iayer processing embodiment of transmitter 100 similar to that shown so FIGURE L In particular _* FIGURE 8 A depicts a embodiment of transmitter 100 that incorporates the CQI/PMI and user data layer-mapping and multiplexing configuration shown in FIGURE 5€, but the exact s m results can be achieved with the configuration shown in FIGURE 4C, For each pari of the processing the output on the branches are illustrated via matrix SOOa- where each column corresponds to a DFTS-OFDM symbol. In particular, matrix 800a illustrates the mapping of control information and user data on a first layer of the resulting vector symbols J 40, and matrix SOOh illustrates the same for a second layer. Matrix 800c illustrates the output of channel interleaver 1 12 for the first layer,

FIGURE SB illustrates PU ^' SCH signaling and UCl multiplexing for per- codeword processing embodiment similar to that of FIGURE ?. As with FIGURE 8 A, matrices S iOa-c are used to iilnstrate the output of particular branches where each column corresponds to a OFFS-OFDM symbol (o to interlaced DPTS-0FDM symbols as output by exteuded channel Interleaver 612% In particular, matrix 810a illustrates the mapping of control information and user data on a first layer of die resulting vector symbols 140, and matrix SlOh illustrates die same for a second layer. Matrix 810c illustrates the output of extended channel interlea ver 612,

In general FIGURES 8A and 8B illustrate the processing of encoded user data, CQI, RI, and HARQ-AC symbols are illustrated for a per4ayer and a per-eodeword processing embodiment _* respectively. I» the figures a four- layer transmission is shown, and the CQI codeword s multi lexed with the first user data codeword, As can be seen from the final output of each layer, the resulting resource mapping is the same m both figures. The same conclusion follows analogously for other transmiss on ranks and CQI-kvdata codeword mappin s.

FIGURE 9 is a structural block diagram showing in greater detail the contents of a particular embodiment of transmitter 100. Transmitter 100 ma represent any suitable device capable of implementing the described resource allocation techniques in wireless eo sniinieation, For e ample. In particular embodiments, transmitter 100 represents a wireless terminal, such as an LTB user equipment (EE). As shown in FIGURE , the illustrated embodiment of transmitter 100 Includes a processor 910, a memory 920, a transceiver 930, and a plurality of antennas 120,

Processor 910 may represent or include any form of processing component, including dedicated microprocessors, general-purpose computers, or other devices capable of processing electronic information. Examples of processor 910 include field- programmable gate arrays (PPGAs), programmable microprocessors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), and any other suitable specific- or general-purpose processors. Although. FIGURE 9 illustrates, tor the sake of simplicity, an embodiment of transmitter 1.00 thai includes a single processor 910, transmitter 100 may include any number of processors 10 configured to teroperate in any appropriate manner.. In particular embodiments, some or all of the tbuetlonabty described above with respect to FIGURES 1-2 and 4-SB ma be implemented by processor 910 executing instructions and/or operating in accordance with its hardwired, logic. Similarly, in. particular embodiments, some or all of Ore functional blocks described above with respect to FIGURES 1-2 and 4-8B may represent processor 010 executing solware.

Memory 920 stores processor instructions, equation parameters, resource allocations, and/or any other data utilized by transmitter 920 during operation. Memory 920 may comprise any collection and arrangement of volatile or non-volatile, local or remote devices suitable for storing data, such as random access memory (RAM}, read only memory (ROM), magnetic storage, optical storage, or an other suitable type of data storage components. Although shown as a single element in FIGURE 9, memory 920 may include one or more h sical components local to or remote from transmi te 100.

Transceiver 930 transmits and receives Rf s gnals over antennas 340a-d. Transceiver 930 ma represent any suitable form of RF transceiver. Although th example embodiment m FIGURE 9 includes a certain number of antennas 340, alternative embodiments of tra smitter 00 may include any appropriate number of antennas 340. Additionally, in particular embodiments, transceiver 930 ma represent, in whole or in part, a portion of processor 10.

FIGURE 10 is a flowchart illustrating example operation of a particular embodiment of transmitter 100 in allocating user data arid control information to transmission resources, in particular, FIGURE 10 illustrates example operation for a particular embodiment of transraitter 100 that transmits certain types of control information (in this case, AO NAK and i information) in vector symbols 140 that contain only control information, while transmitting other types (in this case, CQI/PMI kibrmation) in vector symbols 140 thai include both control infonnation and user data., The steps illustrated in FIGURE 10 may be combined, modified, or deleted where appropriate. Additional steps may also be added to the example operation. Furthermore, the described steps may be performed in any suitable order.

Operation begins in the illustrated example with transmitter 100 encoding the various types of information to be transmitted during a particular subfm e. Thus, at step 1002,. transmitter Ϊ00 encodes bits of a first type of control information to form one or more control codewords. At. step 1004, transmitter 100 encodes bits of a second type of control information to form one or more control codewords, Transmitter 100 also encodes bits of user data, at step 1006, to form one or more user data codewords.. Depending on the types of information to be transmitted and the performance requirements of the communication system, transmitter 100 may use a common encoding scheme or multiple different encoding schemes to encode die information, in particular embodiments, transmitter 100 may replicate bits of the first type of control information (before or after encoding) to ensure dial, m any vector symbol 140 carrying the first type of control inlbnnafion, the first type of control information is mapped to ail transmission layers used for the transmission. Additionally, in particular embodiments, transmitter .100 may encode bits of the second type of control information at a rate to form a first codeword such that a twmber of bits in. the first codeword is equal to £^χ {?-^ _> where 0' is an integer and Q. _m> ,k a number of bits of each modulation symbol on layer and r is a total number of layers over which a user data codeword to be mu tiple ed with the second type of control information will be transmitted. This ma ensu that the second type of control information is mapped to the same i ansmission layers in all vector symbols 140 that carry the second type of control information, even if other transmission layers are used to transmit user data.

After all of the inionnatioa to be transmitted during ihe relevant subirame lias been encoded, transmitter 100 combines the control information to be transmitted with the user data, in particular embodiments, n.ansraltter 100 may combine various types of control information with user data in different ways. For example, in the illustrated embodiment, at step 100S, transmitter 300 multiplexes certain types of control information (t , _f encoded CQI information) with ivser data codewords prior to allocating control information and user data to transmission resources. Transmitter 100 may distribute this control Information to one or more user data codewords so that encoded bits of the control information are concatenated with, the relevant user data codewotx1($). For example, in particular embodiments, transmitter 100 segments each control codeword of the second type into a number of parts that is equal to the total number of layers (r) over which the relevant user data codeword(s) to be multiplexed will be transmitted. Transmitter 100 may perform this segmenting in such a manner that, wh n transmitter 100 subsequ ntly allocates the various types of control information and user data to transmission resources, the part of segmented control codeword that is assigned to a particular layer 0'} will have a length equal to ( ff % } bits. Alternatively, transmitter 100 may distribute the second type of control codeword such that;

where CW ^' " (k) denotes the k -th bit (starting counting from 0) of the control codeword mapped to layer /(starting counting from 1} and CW ^l * ^>:M (m) denotes die m t bit (starting counting If om 0) of the codeword prior to layer mapping. ransmitter 100 then generates a plurality of vector symbols 140 ased on tire control codewords and the user data codewords. Each vector symbol 1 0 comprises a plurality of modulat on sym ls that are each associated with a transmission layer over which the associated modulation symbol will be transmitted. As part of generating these vector s mbols 140. transmitter 100 interleaves bits of the first type of control information with bits of one or more user data control codewords, including any bits of the second type of control information that have been concatenated with user data codewords at step 1010. In particular embodiments, transmitter 100 interleaves the control info mation and user data such that control information of a particular type is map ed to the same layers in all vector symbols 140 transmitted during the relevant subframe that carry the relevant type of control information. Additionally, in particular embodiments, transmitter 100 interleaves the control information and user data in a manner such that control information of certain types (e.g., AC /NACK information and Ri i lbrmation) is mapped to separate vector symbols 140 .from user data, Furthermore, in particular embodiments, transmitter 100 interleaves the control information and user data in a manner such that other types of control information are mapped to vector s mbols 140 to whic user data is also mapped. However, in particular embodiments, these other types of control information are still mapped to the same set of transmission layers in all vector symbols 140 transmitted during the suhtranie that carry the relevant fype(s) of control information.

After interleaving the bits of control information and user data, transmitter 100 may scrambl the interleaved hits. Thus, in the illustrated example, transmitter 100 generates a scrambling sequence or sequences, at step 1012, and applies tire scrambling sequence to groups of die interleaved bits, at step 1014, in particular embodiments, transmitter generates a scrambling sequence for each, layer particular based on a sequence seed (¾,«} associated with that layer. For example, transmitter 100 may generate a scrambling sequence based on a sequenc seed c, _ssi - n _mji - 2 ^SS * q 2 ^ [ j2 2 A ^f i \ where q is the layer associated with the sequence seed, ?½ _i -is a terminal radio network temporary id, n. is a slot number within a radio fr me, and is a cell identifier associated with a cell in which the vector symbols 1 0 are to be transmitted. After generating the scrambling seqnence(s). k such embodiments, transmitter 100 scrambles each group of interleaved its by its corresponding scrambling sequence, as shown at step 1014.

Qnee transmitter 100 has generated vector symbols 140 aad performed any suitable processing, transmitter 100 transmits the generated vector symbols 1 0 at step 5016, As explained above, in particular embodiments, each type of control information is mapped to the same layers m all of the vector symbols 140 that carry that type of control information. Additionally, certak types of control kfbrmatioa (e.g., ACK/NAK information and RI information hem) are mapped to separate vector symbols 140 so that no vector symbols carrying these types of control information also carry user data. However, other types of control, information (e.g., CQl information here) may be mapped to vector symbols 1.40 that also carry user data. Operation of transmitter 1 0 with respec to transmitting the relevant control information and nser data may then end as shown in FIGURE 1 .

Although the present Invention has been described with several embodiments, a myriad of changes, variations, alterations, transformations, and modifications may be suggested to one skilled In the art, and ft is intended that the present invention encompass such changes, variations, alterations, traristbrmatioris, an modifications as fell within the scope of the appended claims.