Title of Invention  "RECEIVER STRUCTURES FOR SPATIAL SPREADING WITH SPACETIME OR SPACEFREQUENCE TRANSMIT DIVERSITY" 

Abstract  A method of receiving data in a wireless communication system, comprising: obtaining received symbols for a data transmission comprising at least one data symbol stream sent with spacetime transmit diversity (STTD) (510); obtaining an effective channel response matrix for the data transmission (512); deriving a spatial filter matrix with the effective channel response matrix (516); and performing spatial processing on the received symbols, based on a 2symbol interval corresponding to the received symbols, with the spatial filter matrix to obtain detected symbols (520). 
Full Text  RECEIVER STRUCTURES FOR SPATIAL SPREADING WITH SPACETIME OR SPACEFREQUENCY TRANSMIT DIVERSITY I. Claim of Priority under 35 U.S.C. 119 [0001] The present Application for Patent claims priority to Provisional Application Serial No. 60/607,371, entitled "Steering Diversity with SpaceTime Transmit Diversity for a Wireless Communication System," filed September 3, 2004; and Provisional Application Serial No. 60/608,226, entitled "Steering Diversity with SpaceTime and SpaceFrequency Transmit Diversity Schemes for a Wireless Communication System," filed September 8, 2004, all assigned to the assignee hereof and hereby expressly incorporated by reference herein. BACKGROUND II. Field [0002] The present invention relates generally to communication, and more specifically to techniques for processing data in a multipleantea communication system. III. Background [0003] A multiantea communication system employs multiple (NT) transmit anteas and one or more (N&) receive anteas for data transmission. The NT transmit anteas may be used to increase system throughput by transmitting different data from the anteas or to improve reliability by transmitting data redundantly. [0004] In the multiantea communication system, a propagation path exists between each pair of transmit and receive anteas. NTNR different propagation paths are formed between the NT transmit anteas and the NR receive anteas. These propagation paths may experience different chael conditions (e.g., different fading, multipath, and interference effects) and may achieve different signaltonoiseandinterference ratios (SNRs). The chael responses of the NTNR propagation paths may thus vary from path to path. For a dispersive communication chael, the chael response for each propagation path also varies across frequency. If the chael conditions vary over time, then the chael responses for the propagation paths likewise vary over time. [0005] Transmit diversity refers to the redundant transmission of data across space, frequency, time, or a combination of these three dimensions to improve reliability for the data transmission. One goal of transmit diversity is to maximize diversity for the data transmission across as many dimensions as possible to achieve robust performance. Another goal is to simplify the processing for transmit diversity at both a transmitter and a receiver. [0006] There is therefore a need in the art for techniques to process data for transmit diversity in a multiantea communication system. SUMMARY [0007] Techniques for transmitting and receiving data using a combination of transmit diversity schemes to improve performance are described herein. In an embodiment, a transmitting entity processes one or more (No) data symbol streams and generates multiple (Nc) coded symbol streams. Each data symbol stream may be sent as a single coded symbol stream or as two coded symbol streams using, e.g., spacetime transmit diversity (STTD), spacefrequency transmit diversity (SFTD), or orthogonal transmit diversity (OTD). The transmitting entity may perform spatial spreading on the NC coded symbol streams and generate NT transmit symbol streams. Additionally or alternatively, the transmitting entity may perform continuous beamforming on the NT transmit symbol streams in either the time domain or the frequency domain. These various transmit diversity schemes are described below. [0008] A receiving entity obtains received symbols for the data transmission sent by the transmitting entity. The receiving entity derives an effective chael response matrix, e.g., based on received pilot symbols. This matrix includes the effects of the spatial spreading and/or continuous beamforming, if performed by the transmitting entity. In an embodiment, the receiving entity forms an overall chael response matrix based on the effective chael response matrix and in accordance with the STTD encoding scheme used by the transmitting entity. The receiving entity then derives a spatial filter matrix based on the overall chael response matrix and in accordance with, e.g., a minimum mean square error (MMSE) technique or a chael correlation matrix inversion (CCMI) technique. The receiving entity then performs spatial processing on a vector of received symbols for each 2symbol interval with the spatial filter matrix to obtain a vector of detected symbols for the 2symbol interval. The detected symbols are estimates of the transmitted coded symbols. The receiving entity performs postprocessing (e.g., conjugation) on the detected symbols, if needed, to obtain recovered data symbols, which are estimates of the transmitted data symbols. [0009] In another embodiment, the receiving entity derives a spatial filter matrix based on the effective chael response matrix. The receiving entity then performs spatial processing on the received symbols for each symbol period with the spatial filter matrix to obtain detected symbols for that symbol period. The receiving entity also performs postprocessing on the detected symbols, if needed, to obtain estimates of data symbols. The receiving entity combines multiple estimates obtained for each data symbol sent with STTD and generates a single estimate for the data symbol. [0010] Various aspects and embodiments of the invention are described in further detail below. BRIEF DESCRIPTION OF THE DRAWINGS [0011] FIG. 1 shows a block diagram of a multiantea transmitting entity. [0012] FIG. 2 shows a block diagram of a singleantea receiving entity and a multiantea receiving entity. [0013] FIG. 3 shows a block diagram of a receive (RX) spatial processor and an RX STTD processor for the MMSE and CCMI techniques. [0014] FIG. 4 shows a block diagram of an RX spatial processor and an RX STTD processor for the partialMMSE and partialCCMI techniques. [0015] FIG. 5 shows a process for receiving data with the MMSE or CCMI technique. [0016] FIG. 6 shows a process for receiving data with the partialMMSE or partial CCMI technique. [0017] FIG. 7 shows an exemplary protocol data unit (PDU). DETAILED DESCRIPTION [0018] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. [0019] The data transmission and reception techniques described herein may be used for multipleinput singleoutput (MISO) and multipleinput multipleoutput (MDVIO) transmissions. A MISO transmission utilizes multiple transmit anteas and a single receive antea. A MDvIO transmission utilizes multiple transmit anteas and multiple receive anteas. These techniques may also be used for singlecarrier and multicarrier communication systems. Multiple carriers may be obtained with orthogonal frequency division multiplexing (OFDM), some other multicarrier modulation techniques, or some other construct. OFDM effectively partitions the overall system bandwidth into multiple (Np) orthogonal frequency subbands, which are also called tones, subcarriers, bins, and frequency chaels. With OFDM, each subband is associated with a respective subcarrier that may be modulated with data, [0020] Transmit diversity may be achieved using various schemes including STTD, SFTD, OTD, spatial spreading, continuous beamforming, and so on. STTD transmits each pair of data symbols from two anteas on one subband in two symbol periods to achieve space and time diversity. SFTD transmits each pair of data symbols from two anteas on two subbands in one symbol period to achieve space and frequency diversity. OTD transmits each pair of data symbols from two anteas on one subband in two symbol periods using two orthogonal codes to achieve space and tune diversity. As used herein, a data symbol is a modulation symbol for traffic/packet data, a pilot symbol is a modulation symbol for pilot (which is data that is known a priori by both the transmitting and receiving entities), a modulation symbol is a complex value for a point in a signal constellation for a modulation scheme (e.g., MPSK or MQAM), and a symbol is any complex value. [0021] Spatial spreading refers to the transmission of a symbol from multiple transmit anteas simultaneously, possibly with different amplitudes and/or phases determined by a steering vector used for that symbol. Spatial spreading is also called steering diversity, transmit steering, pseudorandom transmit steering, and so on. Spatial spreading may be used in combination with STTD, SFTD, OTD, and/or continuous beamforming to improve performance. [0022] Continuous beamforming refers to the use of different beams across the NF subbands. The beamforming is continuous in that the beams change in a gradual instead of abrupt maer across the subbands. Continuous beamforming may be performed in the frequency domain by multiplying the symbols for each subband with a beamforming matrix for that subband. Continuous beamforming may also be performed in the time domain by applying different cyclic or circular delays for different transmit anteas. [0023] Transmit diversity may also be achieved using a combination of schemes. For example, transmit diversity may be achieved using a combination of either STTD or SFTD and either spatial spreading or continuous beamforming. As another example, transmit diversity may be achieved using a combination of STTD or SFTD, spatial spreading, and continuous beamforming. [0024] FIG. 1 shows a block diagram of an embodiment of a multiantea transmitting entity 110. For this embodiment, transmitting entity 110 uses a combination of STTD, spatial spreading, and continuous beamforming for data transmission. A transmit (TX) data processor 112 receives and processes ND data streams and provides ND data symbol streams, where ND1. TX data processor 112 may process each data stream independently or may jointly process multiple data streams together. For example, TX data processor 112 may format, scramble, encode, interleave, and symbol map each data stream in accordance with a coding and modulation scheme selected for that data stream. A TX STTD processor 120 receives the ND data symbol streams, performs STTD processing or encoding on at least one data symbol stream, and provides NC streams of coded symbols, where Nc ND. In general, TX STTD processor 120 may process one or more data symbol streams with STTD, SFTD, OTD, or some other transmit diversity scheme. Each data symbol stream may be sent as one coded symbol stream or multiple coded symbol streams, as described below. [0025] A spatial spreader 130 receives and multiplexes the coded symbols with pilot symbols, performs spatial spreading by multiplying the coded and pilot symbols with steering matrices, and provides NT transmit symbol streams for the NT transmit anteas, where NT Nc. Each transmit symbol is a complex value to be sent on one subband in one symbol period from one transmit antea. NT modulators (Mod) 132a through 132t receive the NT transmit symbol streams. For an OFDM system, each modulator 132 performs OFDM modulation on its transmit symbol stream and provides a stream of timedomain samples. Each modulator 132 may also apply a cyclic delay for each OFDM symbol. NT modulators 132a through 132t provide NT streams of timedomain samples to NT transmitter units (TMTR) 134a through 134t, respectively. Each transmitter unit 134 conditions (e.g., converts to analog, amplifies, filters, and frequency upconverts) its sample stream and generates a modulated signal. NT modulated signals from NT transmitter units 134a through 134t are transmitted from NT transmit anteas 136a through 136t, respectively. [0026] Controller 140 controls the operation at transmitting entity 110. Memory unit 142 stores data and/or program codes used by controller 140. [0027] FIG. 2 shows a block diagram of an embodiment of a singleantea receiving entity 150x and a multiantea receiving entity 150y. At singleantea receiving entity 150x, an antea 152x receives the NT transmitted signals and provides a received signal to a receiver unit (RCVR) 154x. Receiver unit 154x performs processing complementary to that performed by transmitter units 134 and provides a stream of received samples to a demodulator (Demod) 156x. For an OFDM system, demodulator 156x performs OFDM demodulation on the received samples to obtain received symbols, provides received data symbols to a detector 158, and provides received pilot symbols to a chael estimator 162. Chael estimator 162 derives an effective chael response estimate for a singleinput singleoutput (SISO) chael between transmitting entity 110 and receiving entity 150x for each subband used for data transmission. Detector 158 performs data detection on the received data symbols for each subband based on the effective SISO chael response estimate for that subband and provides recovered data symbols for the subband. An RX data processor 160 processes (e.g., symbol demaps, deinterleaves, and decodes) the recovered data symbols and provides decoded data. [0028] At multiantea receiving entity 150y, NR anteas 152a through 152r receive the NT transmitted signals, and each antea 152 provides a received signal to a respective receiver unit 154. Each receiver unit 154 processes its received signal and provides a received sample stream to an associated demodulator 156, Each demodulator 156 performs OFDM demodulation on its received sample stream, provides received data symbols to an RX spatial processor 170, and provides received pilot symbols to a chael estimator 166. Chael estimator 166 derives a chael response estimate for the actual or effective MIMO chael between transmitting entity 110 and receiving entity 150y for each subband used for data transmission. A matched filter generator 168 derives a spatial filter matrix for each subband based on the chael response estimate for that subband. RX spatial processor 170 performs receiver spatial processing (or spatial matched filtering) on the received data symbols for each subband with the spatial filter matrix for that subband and provides detected symbols for the subband. An RX STTD processor 172 performs postprocessing on the detected symbols and provides recovered data symbols. An RX data processor 174 processes (e.g., symbol demaps, deinterleaves, and decodes) the recovered data symbols and provides decoded data. [0029] Controllers 180x and 180y control the operation at receiving entities 150x and 150y, respectively. Memory units 182x and 182y store data and/or program codes used by controllers 180x and 180y, respectively. 1. Transmitter Processing [0030] Transmitting entity 110 may transmit any number of data symbol streams with STTD and any number of data symbol streams without STTD, depending on the number of transmit and receive anteas available for data transmission. The STTD encoding for one data symbol stream may be performed as follows. For each pair of data symbols Ja and A\ to be sent in two symbol periods of the data symbol stream, TX STTD processor 120 generates two vectors Sj = [sa 5jr and s2=0b s]r, where " " denotes the complex conjugate and " T " denotes the transpose. Alternatively, TX STTD processor 120 may generate two vectors s, = 0a s]T and s2 = [sb s]T for each pair of data symbols sa and sb. For both STTD encoding schemes, each vector s,, for t = I, 2, includes two coded symbols to be sent from NT transmit anteas in one symbol period, where NT i 2. Vector st is sent in the first symbol period, and vector s_2 is sent in the next symbol period. Each data symbol is included in both vectors and is thus sent over two symbol periods. The mth coded symbol stream is sent in the mth element of the two vectors s, and S2. For clarity, the following description is for the STTD encoding scheme with =[5 sb]T and s2=[sb sJT. For this STTD encoding scheme, the first coded symbol stream includes coded symbols ss and s, and the second coded symbol stream includes coded symbols sb and  s. [0031] Table 1 lists four configurations that may be used for data transmission. An NDxNc configuration denotes the transmission of ND data symbol streams as NC coded symbol streams, where ND 1 and Nc ND. The first column identifies the four configurations. For each configuration, the second column indicates the number of data symbol streams being sent, and the third column indicates the number of coded symbol streams. The fourth column lists the ND data symbol streams for each configuration, the fifth column lists the coded symbol stream(s) for each data symbol stream, the sixth column gives the coded symbol to be sent in the first symbol period (t ~ I) for each coded symbol stream, and the seventh column gives the coded symbol to be sent in the second symbol period (t2) for each coded symbol stream. The number of data symbols sent in each 2symbol interval is equal to twice the number of data symbol streams. The eighth column indicates the number of transmit anteas required for each configuration, and the ninth column indicates the number of receive anteas required for each configuration. As shown in Table 1, for each data symbol stream that is sent as one coded symbol stream without STTD, the data symbol sent in the second symbol period (t = 2) is conjugated to match the conjugation performed on the data symbols in the STTD encoded data symbol stream. (Table Remove) [0032] As an example, for the 2x3 configuration, two data symbol streams are sent as three coded symbol streams. The first data symbol stream is STTD encoded to generate two coded symbol streams. The second data symbol stream is sent without STTD as the third coded symbol stream. Coded symbols and are sent from at least three transmit anteas in the first symbol period, and coded are sent in the second symbol period. A receiving entity uses at least two receive anteas to recover the two data symbol streams. [0033] Table 1 shows four configurations that may be used for data transmission whereby each configuration has at least one STTD encoded data symbol stream. Other configurations may also be used for data transmission. In general, any number of data symbol streams may be sent as any number of coded symbol streams from any number of transmit anteas, where ND 1 , Nc ND , NT Nc , and NR ND . [0034] The transmitting entity may process the coded symbols for spatial spreading and continuous beamforming as follows: where s,(k) is an Nc xl vector with NC coded symbols to be sent on subband k in symbol period t; G(k) is an Nc xNc diagonal matrix with Nc gain values along the diagonal for the NC coded symbols in s,(k) and zeros elsewhere; V(£) is an NT x Nc steering matrix for spatial spreading for subband k; B(fc) is an NT x NT diagonal matrix for continuous beamforming for subband x, (k) is an NT x 1 vector with NT transmit symbols to be sent from the NT transmit anteas on subband k in symbol period t. [0035] Vector st contains NC coded symbols to be sent in the first symbol period, and vector s2 contains NC coded symbols to be sent in the second symbol period. Vectors Sj and s2 may be formed as shown in Table 1 for the four configurations. For example, Sj=[ja sb sc]r and s2 = X  ]r for the 2x3 configuration. [0036] The gain matrix G(&) determines the amount of transmit power to use for each of the NC coded symbol streams. The total transmit power available for transmission may be denoted as Ptotai If equal transmit power is used for the NC coded symbol streams, then the diagonal elements of G(fc) have the same value, which is /PtoW /Nc . If equal transmit power is used for the ND data symbol streams, then the diagonal 10 elements of G(k) may or may not be equal depending on the configuration. The Nc gain values in G(fc) may be defined to achieve equal transmit power for the ND data symbol streams being sent simultaneously. As an example, for the 2x3 configuration, the first data symbol stream is sent as two coded symbol streams and the second data symbol stream is sent as one coded symbol stream. To achieve equal transmit power for the two data symbol streams, a 3x3 gain matrix G(k) may include gain values of streams. Each coded symbol in the third coded symbol stream is then scaled by VPtotai / 2 and is transmitted with twice the power as the other two coded symbols sent in the same symbol period. The NC coded symbols for each symbol period may also be scaled to utilize the maximum transmit power available for each transmit antea. In general, the elements of G(k) may be selected to utilize any amount of transmit power for the Nc coded symbol streams and to achieve any desired SNRs for the ND data symbol streams. The power scaling for each coded symbol stream may also be performed by scaling the columns of the steering matrix V(£) with appropriate gains. [0037] A given data symbol stream (denoted as {s}) may be sent as one coded symbol stream (denoted as {?}) in other maers. In one embodiment, the gain matrix G(fc) contains ones along the diagonal, and coded symbol stream {?} is transmitted at the same power level as the other coded symbol streams. For this embodiment, data symbol stream {s} is transmitted at lower transmit power than an STTD encoded data symbol stream and achieves a lower received SNR at the receiving entity. The coding and modulation for data symbol stream {s} may be selected to achieve the desired performance, e.g., the desired packet error rate. In another embodiment, each data symbol in data symbol stream {s} is repeated and transmitted in two symbol periods. As an example, for the 2x3 configuration, data symbol sc is sent in two symbol periods, then data symbol sd is sent in two symbol periods, and so on. Similar received SNRs for all ND data symbol streams may simplify processing (e.g., encoding) at both the transmitting and receiving entities. [0038] The steering matrix V(£) spatially spreads the NC coded symbols for each symbol period such that each coded symbol is transmitted from all NT transmit anteas and achieves spatial diversity. Spatial spreading may be performed with various types of steering matrices, such as Walsh matrices, Fourier matrices, pseudorandom matrices, and so on, which may be generated as described below. The same steering matrix V(£) is used for the two vectors Sj(£) and s2(fc) for each subband k. The same or different steering matrices may be used for different subbands. Different steering matrices may be used for different time intervals, where each time interval spans an integer multiple of two symbol periods for STTD. [0039] The matrix B(fc) performs continuous beamforming in the frequency domain. For an OFDM system, a different beamforming matrix may be used for each subband. The beamforming matrix for each subband k may be a diagonal matrix having the following form: where b,(k) is a weight for subband k of transmit antea i. The weight bt(k) may be defined as: (Table Remove) each value of k. The weights &.(£) shown in equation (3) correspond to a progressive phase shift across the NF total subbands of each transmit antea, with the phase shift changing at different rates for the NT transmit anteas. These weights effectively form a different beam for each subband. [0040] Continuous beamforming may also be performed in the time domain as follows. For each symbol period, an Nppoint inverse discrete Fourier transform (IDFT) is symbols for each transmit antea z to generate Np timedomain samples for that transmit antea. The NF timedomain samples for each transmit antea i are then cyclically or circularly delayed with a delay of T,. For example, T, may be defined as: T, = AT(il), for i = l ... NT, where AT may be equal to one sample period, a fraction of a sample period, or more than one sample period. The timedomain samples for each antea are thus cyclically delayed by a different amount. [0041] For simplicity, the following description is for one subband, and the subband index k is dropped from the notations. The receiver spatial processing for each subband may be performed in the same maer, albeit with a spatial filter matrix obtained for that subband. The gain matrix G(fc) does not affect the receiver spatial processing and is omitted from the following description for clarity. The gain matrix G(fc) may also be viewed as being incorporated in the vectors s, and s2. 2. SingleAntea Receiver Processing [0042] A singleantea receiving entity may receive a data transmission sent using the 1x2 configuration. The received symbols from the single receive antea may be expressed as: The MISO chael response h is assumed to be constant over the two symbol periods for vectors s, and s2. [0043] The singleantea receiving entity may derive estimates of the two data symbols sa and ,vb, as follows: (Table Remove) detected symbols The receiving entity may also derive the detected symbols using MMSE processing described below. 3. Multi Antea Receiver Processing [0044] A multiantea receiving entity may receive a data transmission sent using any of the configurations supported by the number of receive anteas available at that receiving entity, as shown in Table 1. The received symbols from the multiple receive anteas may be expressed as: where r, is an NR x 1 vector with NR received symbols for symbol period t; H is an NR x NT chael response matrix; H is an NR xNc effective chael response matrix; and n, is a noise vector for symbol period t. The receiving entity can typically obtain an estimate of H based on a pilot received from the transmitting entity. The receiving entity uses H to recover s, . [0045] The effective chael response matrix H may be expressed as: (Table Remove) the chael gain for coded symbol stream m at receive antea j. The effective chael response matrix G.eff is dependent on the configuration used for data transmission and the number of receive anteas. The MIMO chael response matrix H and the effective chael response matrix Hejr are assumed to be constant over two symbol periods for vectors s, and s2. [0046] For the 1x2 configuration, the effective chael response matrix is an NR x2 matrix that may be given as: Hejf = H • B V = [heffil hi2], where hej n is an effective chael response vector for coded symbol stream m. The multiantea receiving entity may derive estimates of the two data symbols s& and s\,, as follows: where h m is an estimate of heff m , for m = 1, 2 ; " H " denotes the conjugate transpose; and n" and n are postprocessed noise for detected symbols sa and sb , respectively. The data symbols sa and 5b may also be recovered using other receiver spatial processing techniques, as described below. [0047] To facilitate the receiver spatial processing, a single data vector s may be formed for the 2No data symbols included in vectors Sj and s2 sent in two symbol periods. A single received vector r may also be formed for the 2Na received symbols included in vectors fj and r2 obtained in two symbol periods. The received vector r may then be expressed as: where r is a 2NR x 1 vector with 2NR received symbols obtained in two symbol periods; s is a 2ND xl vector with 2 data symbols sent in two symbol periods; Hnfl is a 2NRx2ND overall chael response matrix observed by the data symbols in s; and ,, is a noise vector for the 2No data symbols. The overall chael response matrix H0,, contains twice the number of rows as the effective chael response matrix Heff and includes the effects of STTD, spatial spreading, and continuous beamforming performed by the transmitting entity. The elements of HaU are derived based on the elements of H , as described below. [0048] For the 2x3 configuration, the transmitting entity generates vectors T for four data symbols sasent in two symbol periods for two data symbol streams, as shown in Table 1. Each vector sr contains three coded symbols to be sent from the NT transmit anteas in one symbol period, where NT 3 for the 2x3 configuration. [0049] If the receiving entity is equipped with two receive anteas (NR = 2), then r, is a 2x1 vector with two received symbols for symbol period t, H is a 2xNT chael response matrix, and HeJ is a 2x3 effective chael response matrix. The effective chael response matrix for the 2x3 configuration with two receive anteas, which is denoted as H2xi, may be expressed as: 'V,u V,, Eq(11) [0050] The received symbols for the first symbol period are denoted as rt = [ru r21] r , and the received symbols for the second symbol period are denoted as r2 = [r, 2 r22] T , where r} , is the received symbol from receive antea,/ in symbol period t. These four received symbols may be expressed as: With the above formulation, r may be expressed based on H; 2x3 and s , as shown in equation (10). The matrix H,2x3 is formed from equation set (12) and using the property: r — hs = r h" s. As shown in equation (13), the first two rows of contain all of the elements of H2x3 , and the last two rows of H,',23 contain the elements of H2,3 but rearranged and transformed (i.e., conjugated and/or inverted) due to the STTD encoding on the data symbols. [0052] For the 2x4 configuration, the transmitting entity generates vectors s, =[5a sb sc SA]T and s2 =[£ s sA s]r for two pairs of data symbols (5a and 5b) and (sc and 5j) to be sent in two symbol periods for two data symbol streams. Each vector s, includes four coded symbols to be sent from the NT transmit anteas in one symbol period, where NT 4 for the 2x4 configuration. [0053] If the receiving entity is equipped with two receive anteas (NR = 2 ), then r, is a 2x1 vector with two received symbols for symbol period t, H is a 2xNT chael response matrix, and H is a 2x4 effective chael response matrix. The effective chael response matrix for the 2x4 configuration with two receive anteas, which is denoted as H2x4 , may be expressed as: (Table Remove) [0061] The multiantea receiving entity can derive estimates of the transmitted data symbols using various receiver spatial processing techniques. These techniques include an MMSE technique, a CCMI technique (which is also commonly called a zeroforcing technique or a decorrelation technique), a partialMMSE technique, and a partialCCMI technique. For the MMSE and CCMI techniques, the receiving entity performs spatial matched filtering on 2 received symbols obtained in each 2symbol interval. For the partialMMSE and partialCCMI techniques, the receiving entity performs spatial matched filtering on NR received symbols obtained in each symbol period. A. MMSE Receiver [0062] For the MMSE technique, the receiving entity derives a spatial filter matrix as where Hall is a 2NR x2ND matrix that is an estimate of Han ; (p is an autocovariance matrix of the noise vector nofl in equation (10); and Mmmse is a 2ND x2NR MMSE spatial filter matrix. [0063] The receiving entity may derive Hn,, in different maers depending on how pilot symbols are sent by the transmitting entity. For example, the receiving entity may obtain Heff , which is an estimate the effective chael response matrix Heff , based on symbols. The receiving entity may then derive HaU based on H , as shown in equation (19), (21), (23) or (25) for the four configurations given in Table 1. The receiving entity may also estimate the overall chael response matrix HnH directly based on received pilot symbols. In any case, the second equality in equation (26) assumes that the noise vector noi( is AWGN with zero mean and variance of a . The spatial filter matrix Mmmie minimizes the mean square error between the symbol estimates from the spatial filter matrix and the data symbols. [0064] The receiving entity performs MMSE spatial processing as follows: where is a 2NDxl vector with 2No detected symbols obtained for a 2symbol interval with the MMSE technique; is the MMSE filtered noise. The symbol estimates from the spatial filter matrix Mmmje are uormalized estimates of the data symbols. The multiplication with the scaling matrix D provides normalized estimates of the data symbols. B. CCMI Receiver [0065] For the CCMI technique, the receiving entity derives a spatial filter matrix as follows: where Mccm, is a 2ND x2NR CCMI. spatial filter matrix. [0066] The receiving entity performs CCMI spatial processing as follows: = Mccmir , C. PartialMMSE Receiver [0067] For the partialMMSE and partialCCMI techniques, the receiving entity performs spatial matched filtering on the NR received symbols for each symbol period based on a spatial filter matrix for that symbol period. For each STTD encoded data symbol stream, the receiving entity obtains two estimates in two symbol periods for each data symbol sent in the stream and combines these two estimates to generate a single estimate for the data symbol. The partialMMSE and partialCCMI techniques may be used if the receiving entity is equipped with at least NC receive anteas, or NR Nc . There should be at least as many receive anteas as the number of coded symbols transmitted at each symbol period, which is shown in Table 1 . [0068] For the partialMMSE technique, the receiving entity derives a spatial filter matrix as follows: where Beff is an NR x Nc matrix that is an estimate of Heff ; and Mprome s an NC xNR MMSE spatial filter matrix for one symbol period. The effective chael response matrix H is dependent on the configuration used for data transmission and has the form shown in equation (8). [0069] The receiving entity performs MMSE spatial processing for each symbol period as follows: where mmse, is an Nc xl vector with NC detected symbols obtained in symbol period t with the partialMMSE technique; nm,,ue, is the MMSE filtered noise for symbol period t. [0070] The partialMMSE processing provides two vectors )mueil and mmiei2 for the first and second symbol periods, respectively, which are estimates of vectors s, and s2, respectively. The detected symbols in vector mmi needed, to obtain estimates of the data symbols included in vector s2. As an example, for the 2x3 configuration, smmil,,i = C?a sb sc]r and smms vector smmjl,2, si is conjugated to obtain a second estimate of s\» 5 is negated and conjugated to obtain a second estimate of sa, and sA is conjugated to obtain an estimate [0071] For each STTD encoded data symbol stream, the partialMMSE processing provides two detected symbols in two symbol periods for each data symbol sent in that stream. In particular, the partialMMSE processing provides two estimates of sa and two estimates of s, for all four configurations in Table 1 and further provides two estimates of sc and two estimates of s& for the 2x4 configuration. The two estimates of each data symbol may be combined to generate a single estimate of that data symbol. [0072] The two estimates of a data symbol sm may be combined using maximal ratio combining (MRC), as follows: where sm it is an estimate of data symbol sm obtained in symbol period t; ymtt istheSNRof ,ymi, ;and sm is a final estimate of data symbol sm. [0073] The estimate sm 1m,, m, ig th6 mt "th diagonal element of Q defined above for equation (31). [0074] The two estimates of data symbol sm may also be linearly combined, as follows: Equation (34) provides the same performance as the MRC technique if the SNRs of the two estimates sm , and 5m 2 are equal but provides suboptimal performance if the SNRs are not equal. the receiving entity derives a spatial filter matrix for one symbol period as follows: where Mp,.ccm) is an Nc xNR CCMI spatial filter matrix for one symbol period. [0076] The receiving entity performs CCMI spatial processing for each symbol period as follows: [0078] The partialMMSE and partialCCMI techniques may reduce delay (or latency) for data symbol streams sent without STTD. The partialMMSE and partialCCMI techniques may also reduce complexity of the spatial matched filtering since the spatial filter matrix for each symbol period has dimension of Nc xNR whereas the spatial filter matrix for each 2symbol period interval has dimension of 2ND x2NR . 4. Alternate STTP encoding scheme [0079] For clarity, the description above is for the case in which a pair of data symbols STTD encoded into two vectors sfo sb]T and s2=[ ]r. As noted above, the pair of data symbols sa and sb may also be STTD encoded into two vectors §,=[„ s]T and s2 =[b s]r. The various vectors and matrices described above may be different for this alternate STTD encoding scheme. [0080] As an example, for the 2x4 configuration, the transmitting entity may generate vectors S[ = [5a ib sc sJT and s2 = [b y sd s'c]T for two pairs of data symbols (sa and Sb) an(3 (c and SA) to be sent in two symbol periods for two data symbol streams. The data vector s may be given as s = [sa s sc s"d]T, the received vector r may be The vectors s,, s2 and s and the matrix HflH for the other configurations may be derived in similar maer as described above for the 2x4 configuration. [0081] For the alternate STTD encoding scheme, the receiving entity uses the matrix Hj, defined for the alternate STTD encoding scheme, instead of the matrix HaH defined for first STTD encoding scheme, to derive an MMSE spatial filter matrix or a CCMI spatial filter matrix. For the 2x4 configuration, the matrix HflH shown in equation (38) is used instead of the matrix H, shown in equation (23). The receiving entity then performs spatial matched filtering on the received vector r with the spatial filter matrix to obtain s, which is an estimate of s for the alternate STTD encoding scheme. The receiving entity then conjugates the symbols in s, as needed, to obtain the recovered data symbols. [0082] In general, the overall chael response matrix HflH is dependent on the maer in which the STTD encoding is performed by the transmitting entity and any other spatial processing performed by the transmitting entity. The receiving entity performs MMSE or CCMI processing in the same maer, albeit with the overall chael response matrix derived in the proper maer. [0083] The effective chael response matrix Hejr is the same for both STTD encoding schemes and is shown in equation (8). The receiving entity uses H to derive a partialMMSE spatial filter matrix or a partialCCMI spatial filter matrix. The receiving entity then performs spatial matched filtering on the received vector r, for each symbol period with the spatial filter matrix to obtain s,, which is an estimate of s, for the alternate STTD encoding scheme. The receiving entity then conjugates the detected symbols in s, as needed and further combines estimates as appropriate to obtain the recovered data symbols. 5. Receiver Processing [0084] FIG. 3 shows a block diagram of an RX spatial processor 170a and an RX STTD processor 172a, which can implement the MMSE or CCMI technique. RX spatial processor 170a and RX STTD processor 172a are one embodiment of RX spatial processor 170 and RX STTD processor 172, respectively, for multiantea receiving entity 150y in FIG. 2. Chael estimator 166 derives the effective chael response estimate H based on received pilot symbols, as described below. Matched filter generator 168 forms the overall chael response estimate Ho(, based on H and derives an MMSE or CCMI spatial filter matrix M for a 2symbol interval based on jftoH, as shown in equation (26) or (28). [0085] Within RX spatial processor 170a, a preprocessor 310 obtains the received vector r, for each symbol period, conjugates the received symbols for the second symbol period of each 2symbol interval, and forms the received vector r for each 2 symbol interval, as shown in equation (17). A spatial processor 320 performs spatial matched filtering on the received vector r with the spatial filter matrix M and provides vector s, as shown in equation (27) or (29). Within RX STTD processor 172a, an STTD postprocessor 330 conjugates the symbols in vector s, as needed, and provides 2No recovered data symbols for each 2symbol interval. A demultiplexer (Demux) 340 demultiplexes the recovered data symbols from STTD postprocessor 330 onto ND recovered data symbol streams and provides these streams to RX data processor 174. [0086] FIG. 4 shows a block diagram of an RX spatial processor 170b and an RX STTD processor 172b, which can implement the partialMMSE or partialCCMI technique. RX spatial processor 170b and RX STTD processor 172b are another embodiment of RX spatial processor 170 and RX STTD processor 172, respectively. Chael estimator 166 derives the effective chael response estimate H . Matched filter generator 168 generates a partialMMSE or partialCCMI spatial filter matrix Mp for one symbol period based on Hejj, as shown in equation (30) or (35). [0087] Within RX spatial processor 170b, a spatial processor 420 performs spatial matched filtering on the received vector r, for each symbol period with the spatial filter matrix Mp for that symbol period and provides vector s,, as shown in equation (31) or (36). Within RX STTD processor 172b, an STTD postprocessor 430 conjugates the detected symbols in vector s,, as needed, and provides Nc data symbol estimates for each symbol period. A combiner 432 combines two estimates for each data symbol sent with STTD, e.g., as shown in equation (32) or (34), and provides a single estimate for that data symbol. A demultiplexer 440 demultiplexes the recovered data symbols from combiner 432 onto ND recovered data symbol streams and provides these streams to RX data processor 174. [0088] FIG. 5 shows a process 500 for receiving a data transmission with the MMSE or CCMI technique. Received symbols are obtained for the data transmission, which includes at least one STTD encoded data symbol stream (block 510). An effective chael response matrix is obtained, e.g., based on received pilot symbols (block 512). An overall chael response matrix is formed based on the effective chael response matrix and in accordance with the STTD encoding scheme used for the data transmission (block 514). A spatial filter matrix is derived based on the overall chael response matrix and in accordance with, e.g., the MMSE or CCMI technique (block 516). A vector of received symbols is formed for each 2symbol interval (block 518). Spatial processing is performed on the vector of received symbols for each 2symbol interval with the spatial filter matrix to obtain a vector of detected symbols for the 2 symbol interval (block 520). Postprocessing (e.g., conjugation) is performed on the detected symbols, if needed, to obtain recovered data symbols (block 522). [0089] FIG. 6 shows a process 600 for receiving a data transmission with the partial MMSE or parti alCCMI technique. Received symbols are obtained for the data transmission, which includes at least one STTD encoded data symbol stream (block 610). An effective chael response matrix is obtained, e.g., based on received pilot symbols (block 612). A spatial filter matrix is derived based on the effective chael response matrix and in accordance with, e.g., the MMSE or CCMI technique (block 614). Spatial processing is performed on the received symbols for each symbol period with the spatial filter matrix to obtain detected symbols for the symbol period (block 616). Postprocessing (e.g., conjugation) is performed on the detected symbols, if needed, to obtain estimates of data symbols (block 618). Multiple estimates of each data symbol sent with STTD are combined to obtain a single estimate for the data symbol (block 620). 6. SFTD and spatial spreading [0090] The transmitting entity may also use a combination of SFTD, spatial spreading, and possibly continuous bearnforming. For each configuration shown in Table 1, the transmitting entity may generate two vectors Sj and s_2 for 2No data symbols to be sent on two subbands in one symbol period for ND data symbol streams. The transmitting entity may spatially spread and send vector Sj on one subband in one symbol period and spatially spread and send vector s2 on another subband in the same symbol period. The two subbands are typically adjacent subbands. The receiving entity may derive the overall chael response matrix HaH as described above, except that the first NR rows of Hfl,, are for the first subband (instead of the first symbol period) and the last NR rows of Hfl// are for the second subband (instead of the second symbol period). The receiving entity may perform MMSE, CCMI, partialMMSE, or partialCCMI processing in the maer described above. 7. Steering matrices for spatial spreading [0091] Various types of steering matrices may be used for spatial spreading. For example, the steering matrix V may be a Walsh matrix, a Fourier matrix, or some other matrix. A 2x2 Walsh matrix W2x2 be expressed as W = An NxN Fourier matrix DNxN has element dlim in the nth row of the mth column, which may be expressed as: Fourier matrices of any square dimension (e.g., 2, 3, 4, 5, and so on) may be formed. [0092] A Walsh matrix WNxN, a Fourier matrix DNxN, or any other matrix may be used as a base matrix BNxN to form other steering matrices. For an N xN base matrix, each of rows 2 through N of the base matrix may be independently multiplied with one of M different possible scalars. MN1 different steering matrices may be obtained from MN different permutations of the M scalars for the N 1 rows. For example, each of rows 2 through N may be independently multiplied with a scalar of +1, 1, +j, or j, where j = VT. For N = 4, 64 different steering matrices may be generated from a base matrix B4X4 with the four different scalars. Additional steering matrices may be generated with other scalars, e.g., e±J3"'4, e±J"'4, e±J', and so on. In general, each row of the base matrix may be multiplied with any scalar having the form eje, where 9 may be any phase value. NxN steering matrices may be generated from the NxN base matrix as V(i) = gN B'NxN, where gN = 1/VN and B'NXN is the ith steering matrix generated with the base matrix BNxN. The scaring by gN =1/VN ensures that each column of V(i) has unit power. [0093] The steering matrices may also be generated in a pseudorandom maer. The steering matrices are typically unitary matrices having columns that are orthogonal to one another. The steering matrices may also be orthonormal matrices having orthogonal columns and unit power for each column, so that V" V = 1, and I is the identity matrix. A steering matrix of a dimension that is not square may be obtained by deleting one or more columns of a square steering matrix. [0094] Different steering matrices may be used for different time intervals. For example, different steering matrices may be used for different symbol periods for SFTD and for different 2symbol intervals for STTD and OTD. For an OFDM system, different steering matrices may be used for different subbands for STTD and OTD and for different pairs of subbands for SFTD. Different steering matrices may also be used for different subbands and different symbol periods. The randomization provided by spatial spreading (across time and/or frequency) with the use of different steering matrices can mitigate deleterious effects of a wireless chael. [0095] FIG. 7 shows an exemplary protocol data unit (PDU) 700 that supports MISO and MEMO transmissions. PDU 700 includes a section 710 for a MIMO pilot and a section 720 for data. PDU 700 may also include other sections, e.g., for a preamble, signaling, and so on. A MIMO pilot is a pilot that is sent from all transmit anteas used for data transmission and allows a receiving entity to estimate the MISO or MIMO chael used for data transmission. The MEMO pilot may be transmitted in various maers. [0096] In an embodiment, the transmitting entity transmits a "clear" MEMO pilot (i.e., without spatial spreading) from all NT transmit anteas, as follows: I'(,0 = W(0P() , for = 1 ... L, Eq(41) where p(fc) is an NT xl vector with NT pilot symbols sent on subband k; W(0 is an NT x NT diagonal Walsh matrix for symbol period t; and x/0,(M) is an NT xl vector with NT spatially processed symbols for the clear MEMO pilot for subband k in symbol period t. The NT transmit anteas may be assigned NT different Walsh sequences of length L, where L NT. Each Walsh sequence corresponds to one diagonal element of W(0. Alternatively, the transmitting entity may generate the clear MEMO pilot as: luot(fci0 = w(0  p(fc) where p(k) is a scalar for a pilot symbol, and w(0 is an NTxl vector with the Walsh sequences assigned to the NT transmit anteas. For simplicity, the continuous beamforming is not shown in equation (41) but is typically performed in the same maer, if at all, for both pilot and data transmission. The MEMO chael is assumed to be constant over the length of the Walsh sequences. [0097] The received pilot symbols obtained by the receiving entity for the clear MEMO pilot may be expressed as: r;,D, (,0 = H(fc) • W(0' P(fc) + n() , for t = 1 ... L, Eq (42) where rj(/or(.0 is an NRxl vector with NR received pilot symbols for the clear MEMO pilot for subband k in symbol period t. 31 [0098] The receiving entity may derive an estimate of the MEMO chael matrix H( based on the clear MEMO pilot. Each column of H(&) is associated with a respective Walsh sequence. The receiving entity may obtain an estimate of A; ,•(&), which is the chael gain between the ith transmit antea and thejth receive antea, as follows. The receiving entity first multiplies thejth element of r™te(£,l) through r"/0/(£,L) by the L chips of Walsh sequence W; assigned to the z'th transmit antea and obtains a sequence of L recovered symbols. The receiving entity then removes the modulation used for pilot symbol p,(fc), which is the z'th element of p(fc), from the L recovered symbols. The receiving entity then accumulates the L resultant symbols to obtain the estimate of h} t ( k ) , which is the element in thejth row and the z'th column of H(fc). The process is repeated for each of the elements of H(&). The receiver entity may then derive an estimate of H (k) based on H(A:) and the known steering matrices used by the transmitting entity. The receiving entity may use Iteff(k) for receiver spatial processing, as described above. [0099] The transmitting entity may send a spatially spread MEMO pilot, as follows: where p(&) is an Nc xl vector with NC pilot symbols to be sent on subband k; W(f) is an Nc xNc diagonal Walsh matrix for symbol period /; V(£) is an NT x Nc steering matrix for spatial spreading for subband k; and ptlot(k,f) is an NTxl vector with NT spatially processed symbols for the spatially spread MIMO pilot for subband k in symbol period t. The Walsh sequences have length of L, where L Nc for the spatially spread MEMO pilot. Alternatively, the transmitting entity may generate the spatially spread MIMO pilot as: x",,Dt (£,') = YCO'YlM'.?(&) where p(k) and w(f) are described above. [00100] The received pilot symbols obtained by the receiving entity for the spatially spread MEMO pilot may be expressed as: Eq(44) 32 where r"/to(fc,f) is an NR xl vector with NR received pilot symbols for the spatially spread M3MO pilot for subband k in symbol period t. [00101] The receiving entity may derive an estimate of the effective MIMO chael Hejr(fc) based on the received pilot symbols in r"fte(fc,0, e.g., as described above for the clear MIMO pilot. In this case, the receiving entity removes p(&) and W(f) and obtains A(&), which is an estimate of H(fc) V(fc). Alternatively, the transmitting entity may generate a spatially spread MIMO pilot as: x"ilot(k,t) = W(0'P(£) or x"flof(fc,0 = w(0,p(fc), where W(0 or w(f) performs the spatial spreading. In this case, the receiving entity may form H,(fc), which is an estimate of H(fc) • _W(fc), directly based on the received pilot symbols without any extra processing. In any case, the receiving entity may use Keff(k) for receiver spatial processing. [00102] In another embodiment, the transmitting entity transmits a clear or spatially spread MIMO pilot using subband multiplexing. With subband multiplexing, only one transmit antea is used for each subband in each symbol period. The Walsh matrix W(/) is not needed. [00103] The data transmission and reception techniques described herein may be implemented by various means. For example, these techniques may be implemented in hardware, software, or a combination thereof. For a hardware implementation, the processing units at a transmitting entity may be implemented within one or more application specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. The processing units at a receiving entity may also be implemented within one or more ASICs, DSPs, and so on. [00104] For a software implementation, the techniques described herein may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit (e.g., memory unit 142 in FIG. 1, or memory unit 182x or 182y in FIG. 2) and executed by a processor (e.g., controller 140 in FIG. 1, or controller 180x or 180y in FIG. 2). The memory unit may be implemented within the processor or external to the processor. 00105] Headings are included herein for reference and to aid in locating certain sections. These headings are not intended to limit the scope of the concepts described therein under, and these concepts may have applicability in other sections throughout the entire specification. 00106] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein. We Claim: 1. A method of receiving data in a wireless communication system, comprising: obtaining received symbols for a data transmission comprising at least one data symbol stream sent with spacetime transmit diversity (STTD) (5 10); obtaining an effective channel response matrix for the data transmission (512), wherein the effective channel response matrix is the matrix product comprising the factors a channel response matrix, a diagonal matrix for continuous beamforming to use different beams across subbands and a steering matrix for spatial spreading to transmit a symbol from multiple transmit antennas simultaneously; deriving a spatial filter matrix with the effective channel response matrix (5 16); and performing spatial processing on the received symbols with the spatial filter matrix to obtain detected symbols (520). 2. The method as claimed in claim 1, wherein the obtaining the effective channel response matrix comprises receiving pilot symbols sent with the data transmission, and deriving the effective channel response matrix based on the received pilot symbols. 3. The method as claimed in claim 1, wherein the obtaining the effective channel response matrix comprises receiving pilot symbols sent with spatial spreading, and deriving the effective channel response matrix based on the received pilot symbols. 4. The method as claimed in claim 1, wherein the obtaining the effective channel response matrix comprises receiving pilot symbols sent with spatial spreading and continuous beamforming, and deriving the effective channel response matrix based on the received pilot symbols. 5. The method as claimed in claim 1, wherein the effective channel response matrix in accordance with an STTD encoding scheme used for the data transmission forms an overall channel response matrix, and multiple number of data symbols in according with the STTD scheme forms a single data vector by which the overall channel response matrix is observed by the data symbols in the single data vector. 6. The method as claimed in claim 5, wherein the deriving the spatial filter matrix comprises forming the spatial filter matrix based on the overall channel response matrix and in accordance with a minimum mean square error (MMSE) technique. 7. The method as claimed in claim 5, wherein the deriving the spatial filter matrix comprises forming the spatial filter matrix based on the overall channel response matrix and in accordance with a channel correlation matrix inversion (CCMI) technique. 8. The method as claimed in claim 1, wherein received symbols for a 2symbol interval forms a vector, and the performing spatial processing on the received symbols comprises performing spatial processing on the vector of received symbols for' the 2symbol interval to obtain a vector of detected symbols for the 2symbol interval. 9. The method as claimed in claim 1, wherein the performing spatial processing on the received symbols comprises performing spatial processing on received symbols for each of at least two symbol periods with the spatial filter matrix to obtain detected symbols for the symbol period. 10. The method as claimed in claim 1, wherein the step of obtaining multiple detected symbols and then combining the said multiple detected symbols for each data symbol sent with STTD. 11. The method as claimed in claim 1, wherein the step of obtaining multiple detected symbols and then performing maximal ratio combining of the said multiple detected symbols for each data symbol sent with STTD. 12. The method as claimed in claim 1, wherein the step of performing postprocessing to obtain estimates of data symbols sent for the data transmission on the detected symbols in accordance with an STTD encoding scheme used for the data transmission. 13. The method as claimed in claim 12, wherein the step of performing postprocessing on the detected symbols comprises conjugating the detected symbols, as needed, in accordance with the STTD scheme used for the data transmission. 14. The method as claimed in claim 12, wherein onto one or more data symbol streams sent for the data transmission demultiplex the data symbol estimates. 15. The method as claimed in claim 1, wherein the data transmission comprises multiple data symbol streams and spatial processing on the received symbols with the spatial filter matrix to obtain detected symbols is performed for the plurality of data symbol streams. 16. The method as claimed in claim 15, wherein the step of obtaining the received symbols for the data transmission comprising the multiple data symbol streams with at least one data symbol stream being sent with STTD and at least one data symbol stream being sent without STTD. 17. The method as claimed in claim 15, wherein the step of obtaining the received symbols for the data transmission comprising the multiple data symbol streams with at least two data symbol streams being sent with STTD. 18. The method as claimed in claim 15, wherein the step of obtaining the effective channel responses matrix comprises estimating channel gains for each of the multiple data symbol streams at a plurality of receive antennas, and forming the effective channel response matrix with the estimated channel gains for the multiple data symbol streams and the plurality of receive antennas. 19. The method as claimed in claim 15, wherein the step of performing spatial processing on the received symbols comprises performing spatial processing on received symbols for each of at least two symbol periods with the spatial filter matrix to obtain detected symbols for the plurality of data symbol streams in the symbol period. 20. The method as claimed in claim 1, wherein the step of obtaining an effective channel response matrix for the data transmission, an overall channel response matrix is formed in accordance with an STTD encoding scheme used, and a vector of received symbols for a 2 symbol interval is formed after deriving a spatial filter matrix based on the overall channel response matrix and the spatial processing is performed on the vector of received symbols for the 2symbol interval with the spatial filter matrix to obtain a vector of detected symbols for the 2 symbol interval. 21. The method as claimed in claim 1, wherein the received symbols for a data transmission are sent with spacetime transmit diversity (STTD) and with spatial spreading for all data symbol streams in the data transmission and obtaining an effective channel response matrix for the data transmission includes effects of the spatial spreading. 22. The method as claimed in claim 21, wherein received symbols for a 2symbol interval forms a vector, and the performing spatial processing on the received symbols comprises performing spatial processing on the vector or received symbols for the 2symbol interval with the spatial filter matrix to obtain a vector of detected symbols for the 2 symbol interval. 23. The method as claimed in claim 2 1, wherein the step of performing spatial processing on the received symbols comprises performing spatial processing on received symbols for each of at least two symbol periods with the spatial filter matrix to obtain detected symbols for the symbol period. 24. A method of receiving data in a wireless communication system, comprising: obtaining received symbols for a data transmission comprising at least one data symbol stream sent with spacefrequency transmit diversity (SFTD) or orthogonal transmit diversity (OTD) (5 10); obtaining an effective channel response matrix for the data transmission (5 12), wherein the effective channel response matrix is the matrix product comprising the factors a channel response matrix, a diagonal matrix for continuous beamforming to use different beams across subbands and a steering matrix for spatial spreading to transmit a symbol from multiple transmit antennas simultaneously; deriving a spatial filter matrix with the effective channel response matrix (5 16); and performing spatial processing on the received symbols with the spatial filter matrix to obtain detected symbols (520), wherein the received symbols for a data transmission are sent with spatial spreading for all data symbol streams in the data transmission and wherein obtaining an effective channel response matrix for the data transmission includes effects of the spatial spreading. 25. The method as claimed in claim 24, wherein the received symbols for a data transmission are sent with spacefrequency transmit diversity (SFTD), wherein received symbols for each pair of frequency subbands forms a vector, and the performing spatial processing on the received symbols comprises performing spatial processing on the vector of received symbols for the pair of frequency subbands with the spatial filter matrix to obtain a vector of detected symbols for the pair of frequency subbands. 26. An apparatus for a wireless communication system, comprising: at least one demodulator (156a, 156r) for obtaining received symbols for a data transmission comprising at least one data symbol stream sent with spacetime transmit diversity (STTD); a channel estimator (166) for obtaining an effective channel response matrix for the data transmission, wherein the effective channel response matrix is the matrix product comprising the factors a channel response matrix, a diagonal matrix for continuous beamforming to use different beams across subbands and a steering matrix for spatial spreading to transmit a symbol from multiple transmit antennas simultaneously; a matched filter generator (168) for deriving a spatial filter matrix with the effective channel response matrix; and a spatial processor (170, 320, 420) for performing spatial processing on the received symbols with the spatial filter matrix to obtain detected symbols. 27. The apparatus as claimed in claim 26, wherein the matched filter generator (168) forming an overall channel response matrix based on the effective channel response matrix and in accordance with an STTD encoding scheme used for the data transmission. 28. The apparatus as claimed in claim 26, wherein the spatial processor (170, 320, 420) forming a vector of received symbols for a 2symbol interval, and the spatial processor (170, 320, 420) performing spatial processing on the vector of received symbols for the 2symbol interval to obtain a vector of detected symbols for the 2symbol interval. 29. The apparatus as claimed in claim 26, wherein the spatial processor (170, 320, 420) performing spatial processing on received symbols for each of at least two symbol periods with the spatial filter matrix to obtain detected symbols for the symbol period. 30. The apparatus as claimed in claim 26, wherein a combiner (432) combining multiple detected symbols obtained for each data symbol sent with STTD. 31. The apparatus as claimed in claim 26, wherein the received symbols for a data transmission are sent with spacetime transmit diversity (STTD) for at least one data symbol stream and with spatial spreading for all data symbol streams in the data transmission and the channel estimator (166) for obtaining an effective channel response matrix for the data transmission includes effects of the spatial spreading. 32. The apparatus as claimed in claim 31, wherein the spatial processor (170, 320, 420) forming a vector of received symbols for a 2symbol interval, and the spatial processor (170, 320, 420) performing spatial processing on the vector of received symbols for the 2symbol interval with the spatial filter matrix to obtain a vector of detected symbols for the 2symbol interval. 33. The apparatus as claimed in claim 31, wherein the spatial processor (170, 320, 420) performing spatial processing on received symbols for each of at least two symbol periods with the spatial filter matrix to obtain detected symbols for the symbol period. 34. The apparatus as claimed in claim 26, wherein the at least one demodulator (156a,156r) for obtaining received symbols for a data transmission comprising at least one data symbol stream sent with spacetime transmit diversity (STTD) ; the channel estimator (166) for obtaining an effective channel response matrix for the data transmission; the matched filter generator (168) for deriving a spatial filter matrix with the effective channel response matrix; and the spatial processor (170, 320, 420) for performing spatial processing on the received symbols with the spatial filter matrix to obtain detected symbols. 35. The apparatus as claimed in claim 34, wherein the effective channel response matrix includes effects of spatial processing performed for the data transmission. 36. The apparatus as claimed in claim 34, wherein the matched filter generator (168) forms an overall channel response matrix based on the effective channel response matrix and in accordance with an STTD encoding scheme used for the data transmission. 37. The apparatus as claimed in claim 34, wherein the spatial processor (170, 320, 420) forms a vector of received symbols for a 2symbol interval and performs spatial processing on the vector of received symbols to obtain a vector of detected symbols for the 2symbol interval. 38. The apparatus as claimed in claim 34, wherein the spatial processor (170, 320, 420) performs spatial processing on received symbols for each of at least two symbol periods with the spatial filter matrix to obtain detected symbols for the symbol period. 39. The apparatus as claimed in claim 34, wherein a combiner (432) to combine multiple detected symbols obtained for each data symbol sent with STTD. 40. The apparatus as claimed in claim 34, wherein a postprocessor (330, 430) to perform postprocessing on the detected symbols in accordance with an STTD encoding scheme used for the data transmission to obtain estimates of data symbols sent for the data transmission. 41. An apparatus for a wireless communication system, wherein the received symbols for a data transmission are sent with spatial spreading for all data symbol streams in the data transmission and a channel estimator (1 66) for obtaining an effective channel response matrix for the data transmission includes effects of the spatial spreading, comprising: at least one demodulator (156a, 156r) for obtaining received symbols for a data transmission comprising at least one data symbol stream sent with spacefrequency transmit diversity (SFTD) or orthogonal transmit diversity (OTD); the channel estimator (166) for obtaining an effective channel response matrix for the data transmission, wherein the effective channel response matrix is the matrix product comprising the factors a channel response matrix, a diagonal matrix for continuous bearnforming to use different beams across subbands and a steering matrix for spatial spreading to transmit a symbol from multiple transmit antennas simultaneously; a matched filter generator (168) for deriving a spatial filter matrix with the effective channel response matrix; and a spatial processor (170, 320, 420) for performing spatial processing on the received symbols with the spatial filter matrix to obtain detected symbols. 

2147delnp2007 Correspondence Others(08122011).pdf
2147delnp2007 Drawings(08122011).pdf
2147delnp2007 Form3(08122011).pdf
2147delnp2007 GPA(08122011).pdf
2147delnp2007 Petition137(08122011).pdf
2147delnp2007Abstract(08122011).pdf
2147delnp2007Abstract(18102012).pdf
2147delnp2007Claims(08122011).pdf
2147delnp2007Claims(18102012).pdf
2147delnp2007Correspondence Others(17052012).pdf
2147DELNP2007Correspondence Others(21092011).pdf
2147delnp2007correspondenceothers 1.pdf
2147delnp2007CorrespondenceOthers(18102012).pdf
2147delnp2007correspondenceothers.pdf
2147delnp2007description (complete).pdf
2147delnp2007Form3(17052012).pdf
2147delnp2007Form3(18102012).pdf
2147DELNP2007Form3(21092011).pdf
Patent Number  257474  

Indian Patent Application Number  2147/DELNP/2007  
PG Journal Number  41/2013  
Publication Date  11Oct2013  
Grant Date  07Oct2013  
Date of Filing  20Mar2007  
Name of Patentee  QUALCOMM INCORPORATED  
Applicant Address  5775 MOREHOUSE DRIVE, SAN DIEGO, CALIFORNIA 921211714, USA  
Inventors:


PCT International Classification Number  H04B 7/08  
PCT International Application Number  PCT/US2005/031450  
PCT International Filing date  20050902  
PCT Conventions:
