AU2012203459B2

AU2012203459B2 - MIMO beamforming-based single carrier frequency division multiple access system

Info

Publication number: AU2012203459B2
Application number: AU2012203459A
Authority: AU
Inventors: Robert Lind Olesen; Jung-Lin Pan; Yingming Tsai; Guodong Zhang
Original assignee: InterDigital Technology Corp
Current assignee: InterDigital Technology Corp
Priority date: 2005-09-29
Filing date: 2012-06-14
Publication date: 2015-09-17
Anticipated expiration: 2026-09-25
Also published as: AU2012203459A1

Abstract

A multiple-input multiple-output (MIMO) beamforming-based single carrier frequency division multiple access (SC-FDMA) system is disclosed. At the 5 transmitter, a fast Fourier transform (FFT) is performed on transmission data to generate frequency domain data. The frequency domain transmit data is mapped to assigned subcarriers. An inverse fast Fourier transform (IFFT) is performed on the transmit data mapped to the assigned subcarriers to generate time domain transmit data. The time domain transmit data is transmitted via antennas. At a 10 receiver, an FFT is performed on the received data to generate frequency domain received data. Subcarrier demapping is performed to extract data mapped on the assigned subcarriers. A channel estimator generates a channel matrix which is decomposed into U, D and VH matrices. A channel distortion and interference between transmit and receive antennas are equalized based on the decomposed 15 channel matrices to the extracted frequency domain received data.

Description

Section 29 Reguration 3.2(2) AUSTRALIA Patents Act 1990 ORIGINAL COMPLETE SPECIFICATION STANDARD PATENT Application Number: Lodged: Invention Title: MIMO beamforming-based single carrier frequency division multiple access system The following statement is a full description of this invention, including the best method of performing it known to us: P111AHAU/0710 [00011 MIMO BEAMFORMING-BASED SINGLE CARRIER FREQUENCY DIVISION MULTIPLE ACCESS SYSTEM [0002] FIELD OF INVENTION 10003] The present invention is related to a wireless communication system. More particularly, the present invention is related to a multiple-input multiple-output (MIMO) beamformiing-based single carrier frequency division multiple access (SC-FDMA) system. [00041 BACKGROUND [0005 The third generation partnership project (3GPP) and SGPP2 are currently considering a long term evolution (LTE) of the universal mobile telecommunication system (UMTS) terrestrial radio access (UTRA). Currently, SC-FDMA is being considered for the evolved UTRA (E-UTRA). [0006) In SC-FMA, a plurality of orthogonal subcarriers are divided into a plurality of snbcarrier blocks, (also known as "resource blocks"). A subcarrier block may be a localized subearrier block or a distributed subcarrier block, The localized subcarder block is defined as a set of several consecutive subcarriers and the distributed subcarrier block is defined as a set of several non-consecutive subcarriers. A sibcarrier block is a basic scheduling unit for uplink transmissions in an SC-FDMA system Depending on a data rate or a buffer status, at least one subcarrier block is assigned for a wireless transmit/receive unit (WTRU) for transmission on. [0007] MIMO refers to the type of wireless transmission and reception scheme where both a transmitter and a receiver employ more than one antenna. A MIMO system takes advantage of the spatial diversity or spatial multiplexing to improve the signal-to-noise ratio (SNR) and increases throughput. [0008] SUMMARY [0009] The present invention is related to a MIMO beamforming-based

SC

FDMA system which includes a transnitter and a receiver. At the transmitter, a 2 fast Fourier transform (FFT) is performed on data for transmission to generate frequency domain transmit data. Sub carrier mapping units map the frequency domain transmit data to assigned sub carriers. An inverse Fourier transform (IFFT) is performed on the transmit data mapped to the assigned sub carriers to generate time domain transmit data, and the time domain transmit data is then transmitted via multiple antennas. At the receiver, transmitted data is detected by a plurality of receive antennas. An FFT is performed on received data to generate frequency domain received data. Subcarrier demapping units in the receiver extract data mapped on the assigned subcarriers. A channel estimator in the receiver generates a channel matrix and a singular value decomposition (SVD) unit decomposes the channel matrix into U, D and VH matrices. A channel diagonalization and beamforming unit in the receiver then equalizes a channel distortion and interference between transmit and receive antennas based on decomposed channel matrices to the extracted frequency domain received data. In one aspect the present invention provides a Wireless Transmit/Receive Unit (WTRU) for multiple-input multiple-output (MIMO) communication in a single carrier frequency division multiple access (SC FDMA) system, the WTRU including: a first set of fast Fourier transform (FFT) units configured to perform FFT on data for transmission to generate frequency domain data; a beamformer configured to scale the frequency domain data with an inverse of a diagonal matrix (D) and apply a steering matrix (V) to the scaled frequency domain data, wherein the steering matrix (V) includes eigenvectors of a matrix formed by a product of a Hermitian transpose of a channel matrix (H) and the channel matrix (H), and the diagonal matrix (D) includes a square root of the eigenvalues of a product of the channel matrix (H) and the Hermitian transpose of the channel matrix (H); a plurality of subcarrier mapping units configured to map the frequency domain transmit data on subcarriers assigned for transmission; 2a a first set of inverse Fourier transform (IFFT) units configured to perform IFFT on transmit data mapped to the assigned subcarriers to generate time domain transmit data; and a plurality of transmit antennas configured to transmit the time domain transmit data. In another aspect the present invention provides a base station for multiple-input multiple-output (MIMO) communication in a single carrier frequency division multiple access (SC-FDMA) system, the base station including: a plurality of receive antennas configured to receive transmitted time domain transmit data and generate multiple streams of received data; a set of FFT units configured to perform FFT on the received data to generate frequency domain received data; a plurality of subcarrier demapping units configured to extract data mapped on the assigned subcarriers; at least one channel estimator configured to perform a channel estimation for MIMO channels between a transmitter and a receiver at the base station to generate a channel matrix (H); a channel matrix decomposition unit configured to decompose the channel matrix into a diagonal matrix (D), a unitary matrix (U), and a steering matrix (V), such that H=UDVH, wherein a superscript H denotes a Hermitian transpose; a channel diagonalization and beamforming unit configured to perform receive beamforming on the data mapped on the assigned subcarriers by applying a Hermitian transpose of the unitary matrix U and a matrix comprised of a product of the steering matrix (V) and an inverse of the diagonal matrix (D)to the extracted frequency domain received data; and a second set of IFFT units configured to perform IFFT on the beamformed data to generate time domain received data. In a further aspect the present invention provides a method for multiple-input multiple-output (MIMO) communication in a single carrier frequency division multiple access (SC-FDMA) system, the method including: 2b performing Fast Fourier Transform (FFT) on data for transmission to generate frequency domain data; scaling the frequency domain data with an inverse of a diagonal matrix (D); applying a steering matrix (V) to the scaled frequency domain data to generate beamformed frequency domain data, wherein the steering matrix (V) includes eigenvectors of a matrix formed by a product of a Hermitian transpose of a channel matrix (H) and the channel matrix (H), and the diagonal matrix (D) includes a square root of the eigenvalues of a product of the channel matrix (H) and the Hermitian transpose of the channel matrix (H); mapping the beamformed frequency domain transmit data on subcarriers assigned for transmission; performing Inverse Fast Fourier Transform (IFFT) on transmit data mapped to the assigned subcarriers to generate time domain transmit data; and transmitting the time domain transmit data. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of a transmitter configured ill accordance with the present invention. Figure 2 is a block diagram of a receiver configured in accordance with the present invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENT When referred to hereafter, the terminology "WTRU" includes, but is not limited to, a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a pager, or any other type of device capable of operating in a wireless environment. When referred to hereafter, the terminology IIbase station includes, but is not limited to, a Node-B, a site controller, an access point (AP) or any other type of interfacing device in a wireless environment. The present invention may be implemented in a WTRU or a base station.

[0015] The features of the present invention may be inco4orated into an integrated circuit (IC) or be configured in a circuit comprising a multitude of interconnecting components. [0016] Figure 1 is a block diagram of a transmitter 100 configured in accordance with the present invention. It should be noted that Figure 1 is provided as an example and the functions performed by the components shown in Figure 1 nay be performed by more or less physical components. The transmitter 100 includes encoders 102a-102n, modulators 104a-104n, fast Fourier transfbrm (FFT) units 106a-106n, pulse shaping filters 108a-108n, subcarrier mapping units 110a-110n, a beam former 112 (optional), inverse FFT (IFFT) units 114a-114n, cyclic prefix (OP) insertion units 116a-116n and multiple antennas 118a-118n for MIMO. [00171 Data 101a-101n far transmission is encoded by the encoders 102a 1.02n. It should be noted that the transmitter 100 may include only one encoder depending on the system configuration. The encoded input data 103a-103n is modulated by the modulators 104a-104n, respectively, in accordance with a modulation scheme. The modulated input data 105a-105n is processed by the FFT uniLs 106a-106n to be converted into frequency domain data 107a-107n, respectively. The frequency domain data 107a-107n is processed through the pulse shaping filters 106a-108n, respectively, After processing by the pulse shaping filters lOSa-108n, the frequency domain data 107a-107n is mapped to assigned subcarriers by the subcarrier mapping units 110a-110n, respectively. The subcarrier mapped data 1ila-111n may optionally be processed with a transmit beam forming matrix andlor a sealing factor 120 by the beam former 112, which wifl be explained in detail hereinafter. 100181 The sabcarrier mapped data 111a-111n, (or data 113a-113n processed by the beam.former 112), is then processed by the IFFT units 114a 114n to be converted into time domain data 115a-115n, respectively. A OP is then added to the time domain data 115a-115n by the CP insertion units 116a 116n and transmitted via the antennas 118a-118n, respectively. -3- [00191 Figure 2 is a block diagram of a receiver 200 configured in accordance with the present invention. It should be noted that Figure 2 is provided as an example and the functions performed by the components shown in Figure 2 may be performed by more or less physical components. The receiver 200 includes multiple antennas 202a-202n, OP removal units 204a-204n, IFFT units 206a-206n, subcarrier demapping units 208a-208n, a controller 210, pulse shaping filters 212a-212n, a channel estimator 214, a singular value decomposition (SVD) unit 216, a channel diagonalization and beamforming unit 218, IFFT units 220a-220n, demodulators 222a-222n and decoders 224a-224n. [0020] Signals transmitted from the transmitter 100 are detected by the multiple antennas 202a-202n and multiple received data streams 203a-203n are generated. Each received data stream 203a-20 3 n.is processed by the CP removal unit 204a-204n, respectively, to remove the CP which is inserted at the transmitter 100. [0021] After removing the CP, the received data streams 205a-205n are sent to the FFT units 206a-206n to be converted to frequency domain data 207a 207n, respectively. Each of the subcarrier demapping units 208a-208n extracts particular subcarrier signals 209a-209n in accordance with a control signal 211 received from the controller 210. The controller 210 generates the control signal 211 based on the assigned subcarriers for the receiver 200. The assigned subcarriers may be a block of localized subearriers or a set of distributed subcarriers. [00221 The extracted subcarrier data 209a-209n is then processed through the pulse shaping filters 212a-212n, respectively. After processing by the pulse shaping filters 212a-212n, the data 213a-213n is then sent to the channel diagonalization and beamaforming unit 218 and the channel estimator 214. The channel estimator 214 generates a channel impulse response using a known pilot signal 230 and generates a channel matrix Hk for each subcarrier. The channel estimator 214 may be a joint channel estimator, as shown in Figure 2. Alternatively, multiple channel estimators may be used for processing the -4multiple receive data streams 21,3a-218n, respectively, The channel matrix H is sent to the SVD unit 216. [0023] The SVD -unit 216 decomposes the channel matrix ) into a diagonal matrix DCk) and unitary matrices U7" and Vt' such that: )(- k-- fl,(k) Eqnation (1) where superscript H denotes Hermitian transpose. Uk and V, are uniLary matrices for the k-bh user and the n-th subcarrier and comprise eigenvectors of the matrix H(k)H(k)" and H respectively. U()HU(k) -I The diagonal matrix Dk) comprises the square root of the eigenvalues of Hc) (I)'. it should be noted that SVD is an example for channel matrix decomposition, and the channel matrix decomposition may be performed with any other matrix decomposition methods, (such as eigenvalue decomposition (EVD)), to achieve the same results. 100241 In accordance with a first embodiment of the present invention, the decomposed matrices, Uk), D(k) and y-,(), are sent to the channel diagonalization and beanforming unit 218 and the channel diagonalization and beamforiung unit 218 performs frequency domain equalization so hat channel istortions and interferences between antennas are eliminated. [00251 The received signal in frequency domain is expressed as follows: k) )i (k) Equation (2) where Al" and 5 are the received signal and the transmitted data in frequency domain for the n-th subcarrier of the user k, respectively and N k) is a noise. The channel diagonalization and beamforming unit 218 equalizes the channel distortion and interference by applying the matrix U'"s and to the frequency domain received signal 2$'. The resulting signal after diagonalization ,,is expressed as follows: j1Uc= y~"(k)"l(k)H (k) _ + Tk(k)z k)-(k)I(k); Eq"Iuation (3) -5which is frequency domain data plus noise. [0026] Equation (3) is a zero forcing solution for performing a beamforming only at the receiver 200. This solution may equalize the channel distortion and antenna interference, but enhances noise. [0027] After channel diagonalization. by the channel diagonalization and beamforming unit 218, the data 219a-219n is processed by the IFFT units 220a 220n to be converted to time domain data 221a-221n, respectively. The time domain data 221a-221n is demodulated by the demodulators 222a-222n, respectively, and the demodulated data 223a-223n is processed by the decoders 224a-224n to generate estimated data 225a-225n, respectively. Only one decoder may be used depending on the system confguration. [0028] In accordance with a second embodiment of the present invention, a beam forming is performed both at the transmitter 100 and the receiver 200. At the transmitter 100, the data 101 for transmission is scaled with an inverse of the diagonal matrix D and multiplied by the steering matrix V by the beamforier 112. Alternatively, the transmitter 100 may apply only the steering matrix V. The matrices D and V may be fed back by the receiver 200 to the transmitter 100. Alternatively, the transmitter 100 may include a channel estimator and an SVD unit such that the D and V matrices may be obtained by the transmitter 100 based on channel reciprocity. This operation is expressed per user and subcarrier as follows: 3(k> - Ttk)D Mk i5). Equation (4) [00293 The received signal is expressed as follows: +- SC + Equation (5) 10030] At the receiver 200, a receive beamforming is performed by multiplying a matrix Uk)" on the received signal FPO by the channel diagonalization and beamforming unit 218. The resulting signal after beamnforning is as follows: . 1 k) + U )"(C) Eqation (6) -6- [0031] Equation (6) is a zero forcing solution for performing a beamforming both at the transmitter 100 and the receiver 200. This solution avoids noise enhancement problem of the solution in Etquation (3) by performing a pre beamforming with equalization at the transmitter 100. However, the solution in Equation (7) enlarges the peak-to-average power ratio (PAPR) at the transmitter 100. [00321 In accordance with a third embodiment of the present invention, a minimum mean square error (MMSE) solution is used to suppress a PAPR at the transmitter 100. The beamiorming at the transmitter 100 in accordance with the 'third embodiment requires feedback information from the receiver 200. The feedback information includes D,) and V,*) 'matrices and estimated SNR. The feedback information may be fall feedback information or partial feedback information. The beamformer 122 of the transmitter 1.00 scales and steers the data 101 for transmission based on MMSE solution as follows: -~ ye) .3< 1 ). Equation (7) [0033] The received signal is expressed as fbilows: ) _l-Ck), J(A)+± Equation (8) 0034] After the channel diagonlization and beamforming unit 21.8 perTrms a receive beamforming by multiplying a matrix Uik')", the resulting signal is expressed as follows: _ . 1u)+U . Equation (9) [00351 The PAPR is reduced as shown in Equation ( 7 ). The estimated data at the receiver 200 approaches the transmitted data when a signal-to-noise ratio (SNR) is large as shown in Equation (9), 10036] In accordance with a fourth embodiment, a beamforming is performed only at the receiver 200 and no feedback is sent to the transmitter 100. A received signal after receive beamforming and noise suppression by the channel diagonalization and beamforming unit 218 based on MMBE solution is expressed as follows: D 2 12 +;2 and Equation (10) f) =VCk). ) 2 7 (k)H (k) + )(k) k UHN(k) . Equation (11) n T'Dk) 2 +02 1 _(k) 12 +02 e q [00371 As shown in Equation (11), the equalized signal after beamforming at the receiver 200 approaches transmitted data at a high SNR. This is because the middle term 2 becomes identity at a high SNR and p()?? 1'. At I D 12 +o a low SNR, the equalized beamforming signal at the receiver 200 is estimated with an approximation error, (i.e., A? J (k) plus the error caused by noise), [00381 Embodiments. [00391] 1. An SO-FDMA system wherein a portion of a plurality of subearriers is assigned to a transmitter and a receiver for communication. [0040] 2. The system of embodiment 1 comprising aMMO transmitter. [00411 3. The system of embodiment 2 wherein the MIMO transmitter comprises a first set of FFT units for performing FFT on data for transmission to generate frequency domain data. [0042] 4. The system of embodiment 3 wherein the MIMO transmitter comprises a plurality of subcarrier mapping units for mapping the frequency domain transmit data on subcarriera assigned for the MIMO transmitter and a MIMO receiver. 10043] 5. The system of embodiment 4 wherein the MIMO transmitter compnses a first set of IFFT units for performing IFFT on transmit data mapped to the assigned subcarriers to generate time domain transmit data. [0044] 6. The system of embodiment 5 wherein the MIMO transmitter comprises a plurality of transmit antennas for transmitting the time domain transmit data. -8- [00451 7. The system as in any of the embodiments 1-6, comprising a MIMO receiver. [00461 8. The system of embodiment 7 wherein the MIMO receiver comprises a plurality of receive antennas for receiving the transmitted time domain transmit data and generating multiple streams of received data. [00471 9. The system of embodiment 8 wherein the MIMO receiver comprises a second set of FFT units for performing FFT on the received data to generate frequency domain received data. [00481 10. The system of embodiment 9 wherein the MIMO receiver comprises a plurality of subcarrier demapping units for extracting data mapped on the assigned subcarriers. [0049] 11. The system as in any of the embodiments 7-10, wherein the MIMO receiver comprises at least one channel estimator for performing channel estimation for MIMO channels between the transmitter and the receiver to generate a channel matrix. [00501 12. The system of embodiment 11 wherein the MIMO receiver comprises a channel matrix decomposition unit for decomposing the channel matrix into a diagonal matrix D and unitary matrices U and V, wherein a superscript H denotes a Hermitian transpose. [0051] 13. The system of embodiment 12 wherein the MIMO receiver comprises a channel diagonalization and beamforming unit for equalizing a channel distortion by applying at least one of the U, D and VE matrices to the extracted fregency domain received data. [0052] 14. The system of embodiment 13 wherein the MIMO receiver comprises a second set of IFFT units for performing IFFT on the equalized data to generate time domain received data. [0053] 15. The system as in any of the embodiments 13-14, wherein the channel diagonalization and beamforTing unit equalizes the channel distortion based on a zero forcing solution. -9- [0054] 16. The system as in any of the embodiments 13-14, wherein the channel diagonalization and beamforming unit equalizes the channel distortion based on an MMSE solution. [00551 17. The system as in any of the embodiments 2-16, wherein the MIM 0 transmitter further comprises a beanformer for performing a transmit beamforming by applying the V matrix to the frequency domain transmit data. [0056] 18. The system of embodiment 17 wherein the MIMO transmitter obtains the V matrix from the receiver. [0057) 19. The system as in any of the embodiments 17-18, wherein the MIMO transmitter further comprises a second channel estimator for performing channel estimation to obtain the V matrix based on channel reciprocity. [0058] 20. The system as in any of the embodiments 17-19, wherein the beanformeT applies a scaling factor. [0059] 21. The system of embodiment 20 wherein the scaling factor is an inverse D matrix. [0060] 22. The system of embodiment 20 wherein the scaling factor is generated based on the D matrix and a noise variance. [00611 23. The system as in any of the embodiments 1-22, wherein the subcarriers assigned to the MIMO receiver are a block of localized subcarriers. [0062] 24. The system as in any of the embodiments 1-22, wherein the subcarriers assigned to the MIMO receiver are a set of distributed subcarriers. [0063] 25, The system as in any of the embodiments 2-24, wherein the MIMO transmitter further comprises a CP insertion unit for inserting a OP into the time domain transmit data. [0064] 26. The system of embodiment 25 wherein the MIMQ receiver further comprises a CP removal unit for removing the CP from the receivecl data. [0065] 27. The system as in any of the embodiments 10-26, wherein the MIMO receiver farther comprises a controller for generating a control signal indicating the subcarriers which are assigned to the receiver, whereby the subcarrier demapping units extract the particular data mapped on the sub carriers based on the control signal. -10- [00661 28. The system as in any of the embodiments 12-27, wherein the channel matx decomposition unit is an SVD unit. [0067] 29. The system as in any of the embodiments 12-27, wherein the channel matrix decomposition unit is an EVD unit. [0068] 30. The system as in any of the embodiments 2-29, wherein the MIMO transmitter is a WTRU. [0069] 31. The system as in any of the embodiments 7-S0, wherein the MIMO receiver is a base station. [00701 32. The system as in any of the embodiments 2-29, wherein the transmitter is a base station. [00711 33. The system as i any of the embodiments 7-30, wherein the 'receiver is a WTRU, 100721 34. A method for MIMO beamforning in an SO-FDMA system wherein a portion of a plurality of subcarriers is assigned to a transmitter and a receiver for communication. 10073] 35. The method of embodiment 34 comprising the step of the transmitter performi.g FFT on data for transmission to generate frequency domain data. [00741 36. The method of embodiment 35 comprising the step of the transmitter mapping the fregnency domain transmit data to subcarriers assigned for the transmitter and the receiver. [00751 37, The method of embodiment 36 comprising the step of the transmitter performing IFFT on the transmit data mapped to the assigned subcarriers to generate time domain transmit data, [00761 38. The method of embodiment 37 comprising the step of the transmitter transmitting the time domain transmit data via multiple antennas. [0077] 39. The method of embodiment 38 comprising the step of the receiver receiving the transmitted time domain transmit data and generating mnltiple streams of received data. -11-l [0078] 40. The method of embodiment 89 comprising the step of the receiver performing FFT on the received data to generate frequency domain received data. {0079] 41 The method of embodiment 40 comprising the step of the receiver etracting data mapped on the assigned subcarriers. [00801 42. The method of embodiment 41 comprising the step of the receiver performing a channel. estimation of MIMO channels between the transmitter and the receiver to generate a channel matrix. [0081] 4$ The method of embodiment 42 comprising the step of the receiver decomposing the channel matrix into a diagonal matrix D and unitary matrices U and VII, wherein a superscript H denotes a Hermitian transpose. [0082] 44. The method of embodiment 48 comprising the step of the receiver eqnalizing a channel distortion by applying the at least one of the UH, D and V matrices to the extracted frequency domain received data. 10083] 45. The method of embodiment 44 comprising the step of the receiver performing IFFT on the equalized data to generate time domain received data. [0084] 46. The method as in any of the embodiments 44-45, wherein the channel distortion is equalized based on a zero forcing solution. [0085] 47. The method as in any of the embodiments 44-45, wherein the channel distortion is equalized based on an MMSE solution. [0086] 48. The method. as in any of the embodiments 35-47, further comprising the step of the transmitter performing a transmit beamforming by applying the V matrix to the frequency domain transmit data. 100871 49. The method of embodiment 48 wherein the transmitter obtains the V matrix from the receiver. (00881 50. The method as in any of the embodiments 48-49, further comprising the step of the transmitter performing channel estimation to obtain the V matrix based on channel reciprocity. -12- [00891 51. The method as in any of the embodiments 36-50, further comprising the step of the transmitter applying a scaling factor to the frequency domain transmit data. 10090] 52. The method of embodiment 51 wherein the scaling factor is an inverse D matrix. [00911 53. The method of embodiment 51 wherein the scaling factor is generated based on the D matrix and a noise variance. 10092] 54. The method as in any of the embodiments 34-53, wherein the subcarriers assigned to the receiver are a block of localized subcarriers. [00931 55. The method as in any of the embodiments 34-53, wherein the subcarriers assigned to the receiver are a set of distributed s'abcarriers. [0094 56. The method as in any of the embodiments 37-55, further comprising the step of the transmitter inserting a OP into the time domain transmit data. [0095] 57. The method of embodiment 56 comprising the step of the receiver removing the CP from the received data. [00961 58. The method as in any of the embodiments 41-57, further comprising the step of the receiver generating a control signal indicating the subcarriers which are assigned to the receiver, whereby the data mapped on the assigned subcarriers is extracted based on the control signal. [0097] 59. The method as in any of the embodiments 43-58, wherein the channel matrix is decomposed by performing SVD. [00981 60. The method as in any of the embodiments 43-58, wherein the channel matrix is decomposed by performing EVD. [0099] Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention. -13-

Claims

1. A Wireless Transmit/Receive Unit (WTRU) for multiple-input multiple output (MIMO) communication in a single carrier frequency division multiple access (SC-FDMA) system, the WTRU including: a first set of fast Fourier transform (FFT) units configured to perform FFT on data for transmission to generate frequency domain data; a beamformer configured to scale the frequency domain data with an inverse of a diagonal matrix (D) and apply a steering matrix (V) to the scaled frequency domain data, wherein the steering matrix (V) includes eigenvectors of a matrix formed by a product of a Hermitian transpose of a channel matrix (H) and the channel matrix (H), and the diagonal matrix (D) includes a square root of the eigenvalues of a product of the channel matrix (H) and the Hermitian transpose of the channel matrix (H); a plurality of subcarrier mapping units configured to map the frequency domain transmit data on subcarriers assigned for transmission; a first set of inverse Fourier transform (IFFT) units configured to perform IFFT on transmit data mapped to the assigned subcarriers to generate time domain transmit data; and a plurality of transmit antennas configured to transmit the time domain transmit data.

2. The WTRU of claim 1, wherein the subcarriers assigned for transmission are a block of localized subcarriers.

3. The WTRU of claim 1, wherein the steering matrix (V) and the channel matrix H satisfy the equation H=UDVH, wherein U is a unitary matrix including eigenvectors of a product of the channel matrix (H) and a Hermitian transpose of the channel matrix (H), and D is a diagonal matrix including the square root of the eigenvalues of a product of the channel matrix (H) and the Hermitian transpose of the channel matrix (H). 15

4. The WTRU of claim 1, further including a cyclic prefix (CP) insertion unit configured to insert a CP into the time domain transmit data.

5. The WTRU of claim 1, further comprising a receiver configured to receive feedback, wherein the feedback indicates a value of a signal-to-noise ratio (SNR).

6. A base station for multiple-input multiple-output (MIMO) communication in a single carrier frequency division multiple access (SC FDMA) system, the base station including: a plurality of receive antennas configured to receive transmitted time domain transmit data and generate multiple streams of received data; a set of FFT units configured to perform FFT on the received data to generate frequency domain received data; a plurality of subcarrier demapping units configured to extract data mapped on the assigned subcarriers; at least one channel estimator configured to perform a channel estimation for MIMO channels between a transmitter and a receiver at the base station to generate a channel matrix (H); a channel matrix decomposition unit configured to decompose the channel matrix into a diagonal matrix (D), a unitary matrix (U), and a steering matrix (V), such that H=UDVH, wherein a superscript H denotes a Hermitian transpose; a channel diagonalization and beamforming unit configured to perform receive beamforming on the data mapped on the assigned subcarriers by applying a Hermitian transpose of the unitary matrix U and a matrix comprised of a product of the steering matrix (V) and an inverse of the diagonal matrix (D) to the extracted frequency domain received data; and a second set of IFFT units configured to perform IFFT on the beamformed data to generate time domain received data. 16

7. The base station of claim 6, further including a controller configured to generate a control signal indicating the subcarriers which are assigned to a transmitter , whereby the subcarrier demapping units is further configured to extract the particular data mapped on the subcarriers based on the control signal.

8. The base station of claim 6, wherein the channel matrix decomposition unit is a singular value decomposition (SVD) unit.

9. The base station of claim 6, wherein the channel matrix decomposition unit is an eigenvalue decomposition (EVD) unit.

10. The base station of claim 6, wherein the channel diagonalization and beamforming unit equalizes the channel distortion based on a zero forcing solution.

11. The base station of claim 6, wherein the channel diagonalization and beamforming unit equalizes the channel distortion based on a minimum mean square error (MMSE) solution.

12. The base station of claim 6, wherein the diagonal matrix (D) includes a square root of the eigenvalues of a product of the channel matrix (H) and the Hermitian transpose of the channel matrix (H).

13. The base station of claim 6, wherein the unitary matrix (U) includes eigenvectors of a product of the channel matrix (H) and the Hermitian transpose of the channel matrix (H).

14. The base station of claim 6, further including a transmitter configured to transmit feedback, wherein the feedback includes an indication of one or more of the steering matrix (V) or the diagonal matrix (D). 17

15. A method for multiple-input multiple-output (MIMO) communication in a single carrier frequency division multiple access (SC-FDMA) system, the method including: performing Fast Fourier Transform (FFT) on data for transmission to generate frequency domain data; scaling the frequency domain data with an inverse of a diagonal matrix (D); applying a steering matrix (V) to the scaled frequency domain data to generate beamformed frequency domain data, wherein the steering matrix (V) includes eigenvectors of a matrix formed by a product of a Hermitian transpose of a channel matrix (H) and the channel matrix (H), and the diagonal matrix (D) includes a square root of the eigenvalues of a product of the channel matrix (H) and the Hermitian transpose of the channel matrix (H); mapping the beamformed frequency domain transmit data on subcarriers assigned for transmission; performing Inverse Fast Fourier Transform (IFFT) on transmit data mapped to the assigned subcarriers to generate time domain transmit data; and transmitting the time domain transmit data.

16. The WTRU of claim 1, further including a receiver configured to receive feedback, wherein the feedback includes an indication of one or more of the steering matrix (V) or the diagonal matrix (D).

17. The WTRU of claim 1, wherein the subcarriers assigned for transmission are a set of distributed subcarriers.

18. The base station of claim 6, further including a transmitter configured to transmit feedback, wherein the feedback indicates a value of a signal-to noise ratio (SNR). 18

19. The WTRU of claim 1, and substantially as hereinbefore described with reference to the accompanying figures.

20. The base station of claim 6, and substantially as hereinbefore described with reference to the accompanying figures.

21. The method of claim 15, and substantially as hereinbefore described with reference to the accompanying figures. 19