TW200901654A - Data transmitting and receiving method using phase shift based precoding and transceiver supporting the same - Google Patents

Abstract

A method for performing a precoding based on a generalized phase shift or a precoding based on an extended phase shift in a Multi-Input Multi-Output (MIMO) system employing several sub-carriers, and a transceiver for supporting the same are disclosed. A phase-shift-based precoding matrix is generalized by multiplying a diagonal matrix for a phase shift by a unitary matrix for maintaining orthogonality between sub-carriers. In this case, a diagonal matrix part may be extended by multiplying a precoding matrix for removing interference between sub-carriers by a diagonal matrix for a phase shift. By generalization and extension of the phase-shift-based precoding, a transceiver is more simplified, and communication efficiency increases.

Description

200901654 IX. Description of the Invention: [Technical Field] The present invention relates to a multi-input multi-output (ΜΙΜΟ) cable for use in a plurality of subcarriers. A buffer for transmitting and receiving data based on general phase shift precoding, and a transceiver for supporting the same method. [Prior Art] Recently, with the development of information communication technology, various media services and various quality services have been developed and introduced into the market. Therefore, the demand for wireless communication services has rapidly increased throughout the world. In order to actively cope with the needs of the future, it is necessary to increase the capacity of the communication system. A number of methods have been considered for increasing the communication capacity of wireless communications, such as a method for searching for new available frequency bands in all frequency bands, and a method for increasing the efficiency of limited resources. As for a representative example of the post-method, a transceiver that includes a plurality of antennas to utilize the resources to guarantee additional space to obtain diversity gain, or a communication technology for increasing transmission capacity by transmitting data via parallel individual antennas, It has been developed by many companies or developers. In particular, a multi-input multiple-output (MIMO) system based on Orthogonal Frequency Division Multiplexing (OFDM) in a self-communication communication technology will be described hereinafter with reference to FIG. Figure 1 illustrates an FDM system with multiple transmission/reception (Tx/Rx) antennas.

Block diagram of 200901654. Referring to Fig. 1, in the age-old secret search terminal, the channel encoder 101 attaches a redundant bit to a Tx data bit, and |V determines, 兀* 乂 reduces one channel or noise. Negative impact. A mapper 103 converts the data phase; the A~μ^ greet bit το information into data symbol information. A series of parallel to (serlal~to_parallel, s/p) converters lo5 convert the data symbols into parallel-parameter data so that parallel data symbols can be carried on several subcarriers. An encoder 107 converts the parallel data symbols into spatial time signals. In a receiving end, a decoder 109, a parallel-to-serial (p/s) converter 111, a demapper 113, and a channel decoder 115 have a chirp encoder 1〇7 in the transmission end, The S/P converter 105, the mapper 1〇3, and the channel encoder 101 have opposite functions. ΜΙΜΟ-OFDM systems require various technologies to improve data transmission reliability. As for the scheme for increasing the spatial diversity gain, there is a space-time code (STC), a cyclic delay diversity (CDD) or the like. As for the scheme for increasing the signal to noise ratio (SNR), there is beamforming (BF), precoding or the like. In this case, the space time code or cyclic delay diversity scheme is typically used to provide robustness for an open loop where the feedback information cannot be used at the transmission end due to fast time updates of the channel. Conversely, the beam shaping or pre-kicking is typically applied to a closed loop system to maximize signal to noise ratio by using feedback information including a spatial channel property. As for the scheme for increasing the spatial diversity gain in the above-mentioned scheme, 7 200901654 and a scheme for increasing the signal-to-noise ratio, 'the expansion delay diversity and pre-coding will be explained in detail below. When the antenna system transmits the 0FDM signal, the CDD scheme allows the antenna to transmit 〇FDM signals with different delays or amplitudes. Therefore, a receiving end can obtain the frequency diversity gain. FIG. 2 illustrates the transmission end of a MIM0 system based on the CDD scheme. Block diagram. Referring to FIG. 2, an OFDM symbol is allocated to an individual antenna via an S/P converter and a chirp encoder, and a Cyclic Prefix (CP) for preventing inter-channel interference is attached to the OFDM symbol 'and The resulting OFDM symbol with the CP is then transmitted to a receiving end. In this case, a data sequence transmitted to a first antenna is applied to the receiving end without any change, and the other data sequence transmitted to a second antenna is compared with the first antenna. A predetermined number of samples are cyclically delayed, so the cyclically delayed data sequence is transmitted to the second antenna. At the same time, if the CDD scheme is implemented in a frequency domain, the 'cycle delay' can be indicated by the product of the C; phase sequence (or multiplication). A detailed description thereof will be described below with reference to FIG. Figure 3 is a block diagram showing the transmission end of a system based on a conventional phase shift diversity (PSD) scheme. Referring to Figure 3, the different phase sequences of individual antennas (phase sequence 1 to phase sequence Μ) are multiplied by individual data sequences in a frequency domain, an Inverse Fast Fourier Transform (IFFT) system. Execution is performed on the multiplied result, and the IFFT multiplied data is transmitted to the end of one connection 8 200901654. The method described above in Figure 3 is referred to as a phase shifting diversity scheme. In the case of a phase-shifting diversity scheme, a flat fading pass can be changed to a frequency selective channel, a frequency diversity gain can be obtained by a channel programming, or a multi-user diversity gain can be selected by a frequency selection. The program is obtained. Meanwhile, if a closed loop system includes limited feedback information, two precoding schemes, that is, a code thin precoding scheme and a scheme for quantifying the channel information and feeding back the quantized channel information may be used. The codebook precoding encodes the index of a precoding matrix (which has been identified by the transmission/receiver) to the transmitting/receiving end so that it can obtain the SNR gain. Figure 4 is a block diagram showing the input/receive end of a μ IΜ system based on code thin precoding. Referring to FIG. 4, each of the transmission/reception terminals has a finite precoding matrix (the squad to the corpse. The receiving end uses channel information to feed back an optimal precoding matrix cable (/) to the transmitting end' and the transmitting wheel The terminal applies a pre-code matrix corresponding to the feedback index to the transmission data (to /(4)). For reference, the following table shows the ί, 3-bit feedback information is used for - with two antennas to support An exemplary codebook used in the IEEE 802.1 6e system with a space power ratio of 2. The channel code is used to make the back-to-back moments of the channel as multiple [Table 1] Array index I line 1 Matrix index (binary) Line 1 line 2 Matrix Index (Binary) Line 1 Line 2 000 1 0 — 100 0.7941 0.6038-j0.0689 0 1 0.6038+j0.0689 -0.7941 001 0.7940 ΤοΓ^· 0.3289 0.6614-j06740 -0.5801+j0.18I8 -0.7940 0.6614+j0. 6740 -0.3289 010 0.7940 0.0579-j0.6051 uo 0.5112 0.4754+j0.7160 0.0579+j0.6051 -0.7940 0.4754-j0.7160 -0.5112 011 0.7941 -0.2978+j0.5298 Τη- 0.3289 •0.877 State 0-3481 -0.2978 -j0.5298 -0.7941 -0.8779-j0.3481 -0.3289 9

200901654 The phase shift diversity scheme described above can obtain a selective diversity gain in an open loop and can obtain a frequency gain in a closed loop. Due to the advantages of phase shift diversity schemes, many developers have implemented intensive research in shift diversity schemes. However, the phase shift diversity scheme has a multiplex rate of 1, so that it cannot obtain a high transfer rate. Moreover, if the resources are fixed, the phase shift diversity scheme is difficult to obtain the frequency selective diversity gain and the scheduling gain. The codebook precoding scheme requires a small amount of feedback information (i.e., index information) while using a high spatial multiplex rate, so that it can be efficiently transmitted. However, because it is necessary to ensure that a stable channel for feedback information is not applicable to an action environment with abrupt changes in the channel, it can only be used in closed loop systems. SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a phase shifting precoding method, and a transceiver that employs the same method, which substantially obviates one or more of the problems due to the disadvantages of the related art. An object of the present invention is to provide a phase shift precoding method for solving the problem of phase shift diversity and precoding scheme, and a method for applying a shift by using a generalized or extended phase shift precoding matrix in various ways. The method of precoding scheme. Additional advantages, objects, and features of the invention will be set forth in part in the <RTIgt; The object and other advantages of the present invention are that the frequency range is increased in the phase space configuration frequency, and only the capital is allocated, and a one-to-one limitation scheme is solved by the same or by 10 200901654 in the written description of the invention and the scope of the patent application. And the structure specifically indicated in the drawings is realized and achieved. To achieve these and other advantages and in accordance with the purpose of the present invention, an aspect of the present invention provides a method for transmitting a data in a multiple input multiple output (MIMO) system using a plurality of subcarriers, the method comprising Determining a precoding matrix as a part of a phase shift precoding matrix, determining a first diagonal matrix for a phase shift as part of the phase shift precoding matrix, and determining a unit matrix as the phase shifting pre Encoding a portion of the matrix, and precoding by multiplying the phase-shifted precoding matrix by a transmission symbol per resource, wherein the phase-shifted precoding matrix is obtained by using the precoding matrix, the first diagonal matrix And the unit matrix is multiplied to determine. In another aspect of the present invention, there is provided a transceiver for transmitting a data in a multiple input multiple output (MIMO) system using a plurality of subcarriers, the transceiver comprising: a precoding matrix decision mode a group, which determines a precoding matrix as a part of a phase shift precoding matrix, determines a first diagonal matrix for a phase shift as part of the phase shift precoding matrix, and determines a unit matrix as the phase a portion of the precoding matrix, and determining the phase shifting precoding matrix by multiplying the precoding matrix, the first diagonal matrix, and the unit matrix; and a precoding module For precoding by multiplying the phase shift precoding matrix by a transmission symbol per resource. In another aspect of the present invention, a method for receiving a data in a multiple input multiple output (MIMO) system using a plurality of subcarriers is provided.

In the method of 200901654, the method includes the following steps: determining a precoding matrix as a part of a phase shift precoding matrix, and determining a first diagonal matrix for a phase shift as a part of the phase shift precoding matrix, determining An unit matrix is used as a part of the phase-shifted precoding matrix, and each resource-received symbol is decoded based on the phase-shifted pre-coding matrix, wherein the phase-shifted pre-coding matrix is obtained by using the pre-coding matrix The diagonal matrix and the unit matrix are multiplied to determine. In another aspect of the present invention, a method for receiving a data in a multiple input multiple output (MIMO) system using a plurality of subcarriers is provided, the method comprising the steps of: determining a precoding matrix as a phase Part of the shift precoding matrix, determining a first diagonal matrix for a phase shift as part of the phase shift precoding matrix, determining a unit matrix as part of the phase shift precoding matrix, and based on the The phase-shifted precoding matrix decodes each resource-one transmission symbol, wherein the phase-shifted pre-coding matrix is determined by multiplying the pre-coding matrix, the first diagonal matrix, and the unit matrix. According to the transmission and reception method and the receiver of the above aspect, the precoding matrix can be selected to be cyclically repeated in a first codebook according to the resource index (k). The precoding matrix can be selected to be based on a predetermined The resource index of the unit repeat is repeated in a first code order. The predetermined unit can be determined taking into account the space multiplex rate. The precoding matrix can be selected from a portion of the first codebook. Alternatively, the precoding matrix is selected from a second code 12 200901654 containing a portion of the first codebook. The precoding matrix is selectable from the first codebook based on feedback information received from a receiving end. And the feedback information may include a precoding matrix index (PMI) associated with the codebook. The foregoing general description of the present invention and the following detailed description are both exemplary and illustrative, and are intended to be Further explanation of the claimed invention is provided. The present invention provides a phase shifting precoding technique for solving the problems of conventional CDD, PSD, and precoding methods that result in efficient communication execution. In particular, phase-shifted precoding techniques are generalized or extended, and the design of the transceiver is simplified or the communication efficiency is increased. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments embodiments Wherever possible, the same reference numerals will be used to refer to the Before the present invention is described, it should be noted that most of the terms disclosed in the present invention correspond to general terms well known in the art, but some terms have been selected by the applicant as needed and the following will be below the present invention. Revealed in the description. Therefore, the terms defined by the applicant are preferably understood based on their meaning in the present invention. For the convenience of the description and a better understanding of the present invention, the general structures and devices well known in the art are omitted or indicated by block diagrams or flowcharts. Do 13

200901654 The same component symbols used in all figures will be used to refer to the same or similar parts. &lt;First Embodiment&gt; Phase Shift Precoding Matrix Fig. 5 is a block diagram showing main components of a transmitter for performing a phase shift type precoding scheme according to the present invention. A phase-shifted precoding scheme multiplies all streams by a sequence of different phases and transmits the multiplied stream via all antennas. In general, from the perspective of the receiver, if a phase sequence is generated with a small cyclic delay value, then one channel can have frequency selectivity and the size of the channel becomes larger or smaller depending on the portion of a frequency domain. As can be seen from FIG. 5, a transmitter configures a user equipment (UE) to a specific portion of a frequency band that fluctuates with a relatively small cyclic delay value such that it acquires a row from the particular portion. The gain is increased by one of the frequencies to implement a stable channel state. In this case, a phase shift precoding matrix is used in order to apply a regularly increasing or decreasing cyclic delay value to the individual antenna&apos; transmitter. The phase shift precoding matrix (P) can be expressed by the following equation 1: [Equation 1]

Pn,xR &lt;2 'Λ VN„R. VN„2 where k is a subcarrier index or an index of a specific frequency band (k=l, 2, 3, 14

Ο ^precoefing = l〇g2 (det (Iw can be seen as a unit matrix from Equation 3, so Equation 4: 200901654 4,...) or (k = 0, 1, 2, 3, ...), θί ( ==Bu 2, 3, 4), heart Bubu...,

Nt, j = 1, ..., R) are weighted by a complex number determined by "k", Nt is the number of antennas, and R is a spatial multiplex rate. In this case, the complex weighting may have different values depending on an OFDM symbol or a corresponding subcarrier index multiplied by the antenna. The complex weighting can be determined by at least one of the presence or absence of a channel state and feedback information. At the same time, the phase shifting precoding matrix (corpse) of Equation 1 is preferably configured in the form of a unit matrix to reduce the loss of channel capacity in the system. In this case, in order to determine the constitutional condition of the unit matrix, the channel capacity of an open loop system can be expressed by Equation 2: [Equation 2] C„(H) = l〇g2(det(IAfr +^ΗΗΗ)) Among them, the channel matrix of the size of NrxNt and the number of Rx antennas of the team. If the phase-shifted precoding matrix p is applied to the equation ^, the following equation 3 becomes: [Equation 3] + TMΗΡΡηΗη» ' In order to prevent the damage of the overnight capacity, the phase-shifted precoding matrix ρ of the household η must satisfy the following [Equation 4] 15

200901654 ΡΡη=ιΝ where Iw is the η X n unit matrix. In order to configure the phase-shifted precoding matrix 依 in a unit matrix form, the following two conditions must be met, namely, a power limiting condition and an orthogonal limiting condition. The power limit condition allows the size of each row of a matrix to be "1" and can be expressed by Equation 5 below: [Equation 5] ^ίι| +Κ,ι| +···+^„ι|=1»

1 + |&lt;21 + ...+ 4,2 = L +|Ί +.··+Μ4, β =1 The orthogonal constraint allows individual rows to have orthogonality therebetween, and can be expressed by Equation 6 below: [Equation 6] &lt;2+&lt;Α2+-·· + &lt;Λ,2=0^ « + « + ...+ «3 = 0, W\,\W\,R + W2,lW2Jt +· + ^ N„lWN„R = 0 Next, a generalized equation of a (2×2) size-shifted precoding matrix and an equation for satisfying the above two conditions will be detailed below. Equation 7 below shows a phase-shifted precoding matrix with a spatial multiplex rate of 2 under two TX antennas: [Equation 7] k 0^Win 2x2 A 16 200901654 4) One-to-one unit lower equation where Cl, and (Bu 1, 2) is a real number, 0Ki = 1, 2, 3, phase value, and is a subcarrier index of an OFDM symbol. In order to configure the precoding matrix described above in the form of a matrix, the power constraint condition of Equation 8 and the orthogonal constraint condition of Equation 9 below must be satisfied [Equation 8] a, e a, e \p^ejk-\β^

[Equation 9] + (fi2ejkei), a2em =0 where "*" is a conjugate complex number. A sequence of (2x2) phase-shifted precoding moments satisfying equations 8 and 9 is represented by the following equation 10: [Equation 10] 1 1 ejk&amp;2 private 2=7? (strict 1)

U The relationship between 02 and θ3 is represented by the following equation 11: [Equation 11] k6l = -k02 + π The code memory. The setting of at least one precoding matrix can be configured according to a codebook. The formatted precoding matrix can be stored in a transmitting end or a receiving end. The codebook may include precoded seas generated from a variety of different finite θ2 values. In this case, "θ2" may be properly established by a channel state and re-investment or lack of resources. If feedback information is used, "θ2" 17 200901654 to a low value. If the feedback information is not used, "θ2" is set to a high value. As a result, a high frequency diversity gain can be obtained. At the same time, a frequency diversity gain or frequency scheduling gain can be obtained based on the delay sample size applied to the phase shift precoding. • Figure 6 illustrates two applications of phase shift precoding or one phase shift diversity _ according to the present invention. As can be seen from Fig. 6, if a large value of delayed samples (or cyclic delay) is used, a frequency selection period becomes shorter, so a frequency selectivity increases and a frequency diversity gain can be obtained for one channel code. . Therefore, it is preferable to use a large-valued delay sample for an open loop system in which the reliability of the feedback information is deteriorated due to a sudden channel change with time. If a small value of the delayed sample is used, then the channel size is changed. The larger first portion and a second portion in which the channel size becomes smaller will occur in a frequency selection channel that changes from a flat-fading channel. Therefore, the channel size becomes larger in one of the predetermined subcarrier regions of the OFDM signal, and becomes smaller in the other subcarrier regions. In this case, if an Orthogonal Frequency Division Multiple Access (OFDM A) system is accommodated in a multi-user, a target signal is transmitted through a larger one for each user. The channel size band is transmitted, and a signal to noise ratio (SNR) may increase. Moreover, each user most likely has a different large channel size band, so the system can obtain a multi-user diversity schedule gain. From the perspective of the receiving end, it can transmit only the Channel Quality Indicator (CQI) information of a subcarrier area to configure the source as the feedback information, so the amount of feedback information is relatively reduced. For phase-shifted precoding, the delayed samples (or cyclic delays) can be predetermined in the transmitter or can be fed back from a receiver to a transmitter. In addition, the spatial multiplex rate R can also be predetermined in the transceiver. However, the receiver periodically recognizes a channel state' to calculate the spatial multiplex rate, and returns the singular space multiplex rate to a transmitter. Alternatively, the transmitter can use the channel information fed back from the receiver to calculate or change the spatial multiplex rate. &lt;Second embodiment&gt; In general, a phase shift diversity topology is used in a system in which the antenna number system Nt (Nt is a natural number higher than 2) and the spatial multiplex rate system R The phase shift pre-completion matrix described above can be expressed by Equation 12 below:

[Equation 12]

Equation 12 can be considered as a generalized format for a conventional phase shift diversity scheme, so the scheme shown in Equation 12 will be referred to below as a Generalized Phase Shift Diversity (GPSD) scheme. In Equation 12

The k-th sub-carrier with the MIMO-OFDM signal with the space multiplex rate of R and the Tx antenna 19 200901654

GPSD matrix. Also, ¢/(4) is an identity matrix that satisfies = (i.e., the second matrix), and is adapted to minimize interference between subcarrier symbols corresponding to individual antennas. Specifically, in order to maintain a diagonal matrix (i.e., the first matrix) for one phase shift without any change, it is preferable that the condition %π satisfies the condition of the identity matrix. In Equation 12, the phase angle θί (ι=1, .., Nt) of a frequency domain and the delay time Ti(i = 1, , (10) of a time domain have a predetermined relationship, which is expressed by the following Equation 13: [Equation 13] where Nffi is the number of subcarriers of an OFDM signal. A modified example of Equation 12 is shown in the following equation η, so the GPSD matrix can be calculated by Equation 14:

[Equation 14]

Θ

If the GPSD matrix is caused by Equation 14, the signage of each data stream (or 〇fdM subcarrier) is offset by the same phase' so that the GPSD matrix can be easily configured. In other words, the GPSD matrix of Equation 14 contains rows having the same phase, while the GPSD matrix of Equation 12 contains columns having the same phase, so the individual subcarrier symbols are offset by the same phase. If Equation 14 is extended, then 20 200901654 the GPSD matrix can be calculated by Equation 15 below: [Equation 15]

(UA 〇psd^r= ff *. ·* V miscellaneous 0 ...〇0 ... 0, Θ 0 fitik \ 0 0 · ·. \ § (3⁄4 box j &gt;·. · * 0 Q 0 Θ Λ as from the equation It can be seen that the columns and rows of the GPSD matrix have independent phases, so various frequency diversity gains can be obtained. As an example of Equation 12, 14 or 15, two TX antennas and one bit are used.

The GPSD matrix equation of the system of the codebook can be expressed by the following equation 16: [Equation 16] GPS^^[j-a\^ + ^ = 1 In Equation 16, if "α" has been determined, "β" can be easily determined. Therefore, the value of "α" can be fixed to two appropriate values, and the information associated with the value of "α" can be fed back to a codebook index as needed. For example, two conditions can be specified between a transmitter and a receiver, that is, if the index is "〇", then "α" is set to a condition of "0.2", and if the index is "1", then " α is set to another condition of "0.8". A predetermined precoding matrix for obtaining the SNR gain can be used as an example of the unit matrix in Equation 12, 14 or 15. Can be a Walsh 21 200901654

A Hadamard matrix or a DFT matrix is used as the pre-matrix matrix described above. If an Walsh Hadamard matrix is used, an example of the GPSD matrix of Equation 12 can be represented by Equation 17 below:

[Equation 17] η ο ο 1 fiii 1, GPSDkAx4- ^ 0 ^ 0 0 0 0 α 1-1 1 -1 1 l - l - i L 0 0 0 e: _J Uii iJ Equation 17 is in a system with 4 The Tx antenna and the space multiplex rate of 4 are assumed. In this case, the second matrix is properly reconstructed so that a particular Tx antenna (i.e., antenna selection) or adjustable spatial multiplex rate (i.e., level adaptation) can be selected. At the same time, the identity matrix of equations I2, I4 or I5 can be configured in a singular form. Thus the unit matrix formatted by the thin code is stored in a transmission or reception. In this case, the transmitting end receives the code index information from the receiving end, selects a precoding matrix corresponding to the index from its own codebook, and configures a phase shift precoding matrix using Equations 12, 14 or 15. The right one (2x2) or (4x4) size Walsh code is used as the unit matrix %π ' of Equation 12, or 15 to obtain an example of a GPSD matrix, as shown in Tables 2 and 3: [Table 2] twenty two

200901654 ::T pass Rate 1 Rate 2 1 1 i Γ 1 1 1 [Table 3] 4 Tx Rate 1 Rate 2 Rate 4 r ψ η 1 , ί i ' —1 I 1 1 ^ 1 1 1 2 2 2 ' ρ /Ψ ·- τ &lt;Third embodiment&gt; Time-varying generalized phase shift diversity In the GPSD matrix of Equation 12, 14 or 15, the phase angle of a pair of angular matrices (θ〇 and/or a unit matrix ( U) may change with time. For example, one time-varying GPSD of Equation 12 may be expressed by Equation 18 below: [Equation 1 8] GPSDkNtXR(t> 〇m 艺0; eJ^(t)k &gt;:* 丨f ο '· 0 t 0 0 0 寒娜幻 Ntxlid 23 200901654 It is a GPSD matrix of a k-subcarrier of a MIM〇_〇FDM signal with a wind Τχ antenna and a spatial multiplex rate r at a specific time (1). [/々) is the unit matrix (ie, the fourth matrix) that satisfies and is adapted to minimize interference between subcarrier symbols corresponding to individual antennas. / Clearly, in order to maintain one for The characteristics of the unit matrix of the diagonal matrix of the phase shift (ie, the third matrix) are not changed, and preferably the unit matrix of the phase matrix is sufficient. Member. In Equation 18, a phase angle 0i (t) (i = l,. ,,

Nt) and a delay time T:i(t) (i=l, .., Nt) have a predetermined relationship, which is represented by the following equation 19: [Equation 19] m=−2nA where Nfft is an OFDM signal The number of subcarriers. As can be seen from Equations 18 and 19, a time delayed sample value and a unit matrix can change over time. In this case, one of the time units can be set r

I is an OFDM symbol or a predetermined unit time. If a unit matrix for acquiring a time-varying GpSD is represented by a GPSD matrix based on a (2x2) size Walsh code, the following GPSD matrix can be established as shown in Table 4 below: . [Table 4] 24

200901654

Rate 1 Rate 2 l 1 I y If the unit matrix used to obtain the time-varying GPSD is represented by a GPSD matrix based on a (4x4) size Walsh code, the following GPSD matrix can be established as shown in Table 4 below: [Table 5] 4Tx Rate 1 Rate 2 Earn 4 Γ 1 y object Λ::Λ r : r— fn 1 1 〆%(0* CO* __e τ'— ' 1 1 1 i 1 ^微七联g?- Micro.: VII. Although the third embodiment of the above has revealed the time-varying GPSD matrix of the correlation equation 12, it should be understood that the time-varying GPSD matrix can also be applied to the diagonal matrix and the unit matrix of Equations 14 and 15. Therefore, although the following specific embodiments will be described with reference to Equation 12, it is apparent to those skilled in the art that the scope of the following specific embodiments is not limited to the equations 12 and can also be applied to the equations 14 and 15. [Fourth implementation Example> The third matrix of 25 arrays is added to the GPSD matrix, and the pair of corners is extended.

200901654 Shift diversity If one corresponds to a precoding matrix and a single matrix, the GPSD matrix can be established as shown in Equation 2 below [Equation 20] GPSD·R. Compared with Equation 12, the extended GPSD matrix of Equation 20 further includes a (NtXR) size precoding matrix (p) located before the diagonal matrix. Therefore, the size of the diagonal matrix is changed to the (rxR) size. The added precoding matrix can be assigned differently to a particular frequency band or a particular subcarrier symbol. Preferably, in the case of an open loop system, the precoding matrix can be added and set to a fixed matrix.最佳 The best SNR gain can be obtained by increasing the precoding matrix f and X. A transmitting end or receiving end may have a codebook equipped with a complex precoding matrix (P). Meanwhile, in the extended GPSD matrix, at least one of the precoding matrix (P), the phase angle (Θ) of the diagonal matrix, and the unit matrix (U) may change with time. For this purpose, if one index of the next precoding matrix P is fed back in a predetermined time unit or a predetermined subcarrier unit, a specific pre-synthesis matrix p corresponding to the index can be selected from a predetermined codebook. . The extended GPSD matrix according to the fourth embodiment may be as follows:

^ (%xi?(0) e! J

[Equation 23]

0 ... Technician 汝... ♦· ·' 0 *·* (DFT to R) 200901654 Equation 21 means: [Equation 21] Division. ... 戏 』):~渊 I 'f),:: 〇 · · · "As an example of extending the GPSD matrix, a matrix equation of a system including two or four Tx antennas is in Equations 22 and 23 below. Display: [Equation 22] gpsd^ 2 m = (p2 x 2 (ί))( J Jit )k )(^3⁄4 x^) 0 ' · .·· In Equations 22 and 23, although a DFT matrix is used As a unit matrix, the scope of the present invention is not limited to the D FT matrix, and can also be applied to other matrices that satisfy a given unit condition of a Walsh Hadamard code. As for another example of extending the GPSD matrix, one includes four The matrix equations of the system of Tx antennas are shown in Equation 24 below: [Equation 24] 27 200901654

Compared with Equation 12, the extended GPSD matrix of Equation 24 further includes - (NtxN〇 size diagonal matrix (D1) and one (NtxR) size precoding matrix (p), which is located before the pair of angular matrices (D2). The size of the diagonal matrix (D2) is changed to the (RxR) size. The added precoding matrix can be assigned to a specific frequency band or a specific subcarrier symbol differently from %. Preferably, in the open loop system In this case, the added precoding matrix parent ugly can be set to a fixed matrix, and the optimal SNR gain can be obtained by adding the precoding matrix. Preferably, a transmitting end or a receiving end can have a complex pre-prepared The code matrix of the coding matrix (P).

Q ... 9 0 a ϊ * · Q 0 0 D1 (AxsOO)

In this case, by the diagonal matrices D1 and D2, a phase angle can be shifted in two ways in a single system. For example, if a low-value phase shift is used by the diagonal matrix D1, a multi-use can be obtained. The diversity of the scheduling gain. If a high value phase shift is used by the diagonal matrix D2, a frequency diversity gain can be obtained. The diagonal matrix D 1 is adapted to increase system performance, while the other diagonal matrix is adapted to average one channel between streams. Also, a high value phase shift is used by the diagonal matrix D 1 , so the frequency diversity gain can be increased. A high value phase shift diversity is used by the diagonal matrix D2, so that one channel between the streams can be averaged. This gain can be obtained from Equation 21. In this case, the matrix P of Equation 21 must be changed based on a subcarrier 28 200901654 element or a frequency resource unit, and then used without feedback. This modified format can be expressed by the following equation 25: [Equation 25] GP^(X,(〇=(P^,(〇) ο ei9z{t)k Ο :·. 〇(1) Ο ej0Ri,) k ^ 〇 In Equation 25, the calibration refers to a specific case in which individual resource indices (k) use different precoding matrices. Thus, a frequency diversity gain is increased by using a different precoding matrix per resource index (k), and a channel between streams is averaged by using a pair of angular matrices and a unit matrix (U). &lt;Fifth Embodiment&gt; Codebook Subset Restriction Scheme The codebook subset restriction scheme is limited to use some portions of a codebook. If the number of all precoding matrices of the codebook is Wc, only the AUirW precoding matrix can be used according to the codebook subset restriction scheme. A thin code subset restriction scheme can be used to reduce multi-cell interference or system complexity. In this case, the predetermined condition indicated by iVc must be satisfied. For example, if the number of all precoding matrices of the codebook is #c=6, one set of all codes is thin, χβ and one are used to allow only a specific codebook from 4 precoding matrices in the 6 precoding matrix. It can be expressed by the following equation 26: [Equation 26] p __ ip〇pi p2 p3 p4 n5 ) - \ΓΝ^Κ^ rNtxR^rNixR^jrNtxR^&gt;rNi&gt;cR^rNixRj^ 29 200901654 = {Pn,xR&gt; P^ Pn,,rA^} = = [K^ Kx^K^K^} In Equation 26, the equivalent code thin of the codebook Pgr is %. &lt;Sixth embodiment&gt; Precoding matrix cyclic repeating scheme

For example, if one of the precoding matrix sets is predefined at a particular time during the Tx/Rx time, then this can be represented by Equation 27 below: [Equation 27] ρΉ "·..,

GPSDkNiXR K:

kmodNc xR ο ej咕 Ο In Equation 27, the precoding matrix set includes an iVc precoding matrix. Equation 27 can be simplified in the form of Equation 28: [Equation 28] I'* P' xfi = χΛ, A xi?, _ · Ά, χΛ } GP^/X,=(P^r〇nL, T%kvs\ odNc In Equation 27 and Equation 28, the factory ν, π indicates a precoding matrix that is cyclically repeated according to one of the subcarrier indices or a resource index k included in the price precoding matrix in the codebook. In Equation 28, n^xi? is adapted to mix data streams and can be referred to as a rotation matrix. As can be seen from Equation 28, Π^χΛ can be selected according to a spatial multiplex rate (R). Equation 29 below represents: 30 200901654 [Equation 29] Spatial multiplex rate: 2 nk2x2 ίο 1 1 ο \k

e财 ο \

J

Space multiplex rate: 3

nL &quot;0 1 0, k ri 0 0, 0 0 1 or 0 e difficult 0 0 0J 0 ej' DF\ x3 Space multiplex rate: 4 x4

4^4 &quot;0 1 0 0, k (\ 0 0 0 N 0 0 1 0 or 0 0 0 0 0 0 1 0 0 e return 0 0 0 0, 0 0 ej' DFT4 In addition, in one with N In the codebook of a precoding matrix, if a codebook subset restriction scheme based on a specific portion of the codebook of the Node B or the User Equipment (UE) can be applied to the codebook described above, then Nc The precoding matrices must be reduced to Nrestrict precoding matrices and then used. Therefore, in the case of using the equivalent codebook WV, Equation 28 can be expressed by Equation 30 below: [Equation 30] = Μ, - ρ2 ¥,ρ3ν,...piR}=研啊=

GPSDkNiXR=(w^fN^)nkRxR where "k" is a subcarrier index or a frequency resource index. In Equation 31 200901654 ύττ k mod 式 Equation 30, the team is tied to 4. And in Equation 30, the system indicates that the repeated precoding matrix is cyclically repeated according to a subcarrier index or a resource index k included in the Nrestrict precoding matrix included in or within the codebook PGT. &lt;Sixth embodiment-1&gt;

The scheme is repeated by a precoding matrix of a predetermined unit. Further, Equation 28 can also be represented by the following program 3 1 according to one of the frequency resources: [Equation 31] GPSDkN rush or 〇 PSDkNiXR = modA^

P

—modAfc N,xR

lRxR Π

k RxR

In Equation 31, "k" may be a subcarrier index or a virtual resource index, and may be selected between Equation 2 in Equation 31 according to the starting index k. In Equation 31, if "k" is a subcarrier index, a precoding matrix is repeated for v subcarriers and the precoding matrix is based on a pair of iVc precoding matrices included in the codebook βν,π The carrier index k is cyclically repeated. An exemplary list of precoding matrix indices per subcarrier is as follows: [1 122334455 1 122334455...] or [0001 1 1222333444 0001 1 1222333444...] The first one represents v = 2,7\^ = 5 and The case of 1^=1, 2, ..., K, and the 32nd 200901654 both represent the case where v = 3, iVc = 5, k = 0, 1, ..., Κ-l. Here, the number of resources in a sub-frame. Equation 31 shows a specific case in which a precoding matrix is differently established in Nc precoding matrices. The value of v can be determined by considering a spatial multiplex rate of the precoding matrix. For example, the value of v can be indicated by v = .

In addition, in the case of using the code thin subset restriction scheme of Equation 26, the precoding matrix may also be changed based on a predetermined number of subcarrier units or a predetermined number of frequency resource units. This format can be expressed by the following equation 32: [Equation 32] nresirict _ fp〇p2 p3 p5 1 _ \y - iw° W1 W2 W3 \ rNtxR \rNtxR^ rN,xR^rNtxR^rNtxR] ~ YYNtxR ~~ \n N, xR^ n NtxR^n Nt^R^rr NtxR j GPSDkNM =

k RxR Π or

GPSD

NtxR

Comparing Equation 31, the precoding matrix of Equation 32 can also be changed by the V unit. Unlike Equation 31, the precoding matrix of Equation 32 varies in the S D number of the precoding matrix. At the same time, the frequency diversity gain can be varied depending on the number of cyclically repeating precoding matrices or the number of precoding matrices included in the codebook. Therefore, in the case where the codebook subset restriction scheme and the precoding matrix loop repetition scheme are adapted as shown in Equation 32, various schemes for determining the codebook subset are described below. &lt;Fifth Specific Embodiment-1&gt; 33 200901654

The root multiplex rate R code thin subset can be determined differently according to the spatial multiplex rate R. For example, in the case of a low space multiplex rate, the size of the codebook subset is determined to be so large that the frequency diversity gain can be maximized. And in a high space multiplex rate, the size of the code subset is determined to be small, so that complexity can reduce the maintenance performance.

In the case of using a subset of codebooks determined according to the spatial multiplex rate R, the example method can be expressed by the following equation 3: [Equation 33] x2 = {x2» ^N, x2 &gt; ^N , x2 &gt; x2 } » ^restrict = ^ WW(X3 = = 3 ~χ4;, 4, KsMct =1 fm D \ , -modNnslria

GPSDkNiXR= WN:XR

or

GPSDkN

xR w, modNrRe! '.strict

NtxR Π

RxR is indicated by the number of codebook subset precoding matrices determined by the spatial multiplex rate R. Therefore, a system performance and system complexity are improved in the case where the precoding matrix of the codebook adjusted by the codebook subset is cyclically reused. &lt;Fifth Specific Embodiment-2&gt; The scheme of the root channel coding rate is available.

200901654 Codebook subsets can be determined differently depending on the channel coding rate. For example, the frequency diversity gain can be increased when the channel coding rate is low. Therefore, in an environment with spatial multiplex rate, a precoding matrix with different precoding matrix subsets, preferably based on a low channel coding rate, can be used to achieve system performance and system complexity. &lt;Fifth Embodiment 3&gt; The retransmission codebook subset can be determined differently according to retransmission. For example, a subset of codebooks used at the input has a precoding matrix that is different from the precoding matrix of the subset of codebooks that have been used at the inception. That is, depending on the number of transmissions or retransmissions, etc., code samples of different compositions can be used, and thus, the success rate of retransmission can be increased. &lt;Seventh embodiment&gt; Generalized phase shift diversity for power control per transmission antenna I) As for various precoding schemes, different powers per TX antenna can be varied in frequency or time. Therefore, it is possible to increase system performance and effective functions. For example, the power control per Tx antenna can be used with the precoding schemes of Equations 30, 31 and 32. In particular, an example of an equation using a codebook including one precoding matrix is represented by the following equation 34: [Equation 34]

PjV, χβ = X/?,χΛ,· Ά,χΛ } General The code in the phase can be changed and then transmitted. No further set 0 value rate 28 ' type 31 35 200901654

GPSDkNiXR=OmNiXNi(t) or

rNtxR GPSDkNiXR = OmNiXNi (〇 v(,)DU’)=: Π

RxR r I μ λ modi^e n:&gt; 0 a; {t) Π

RxH 0 0 0 In Equation 34, Π^χΛ is adapted to mix data streams, and may also be referred to as a rotation matrix, and n^xi? may also be easily represented by Equation 29. And (0 is indicated by a power control diagonal matrix, so that each TX antenna transmits a data stream with different power according to the mth frequency region and/or t time. &lt;, (/) is used by the iTx Power control element indication of the antenna, the mth frequency zone and/or t time.

An example of Equation 3 2 using a codebook comprising iVwinc (S iVc) precoding matrices is represented by Equation 35 below: [Equation 35]

xR I ^restrict „ fp〇p2 p3 p5 l - W - iw° Wl W2 W3 rNt 乂R ~\rM^R^rN^R9rNtxR^rN,xRj-~ N,xR ~~ \n N,xR^&gt; n N,xR^r N,xR^rr N( G^X,=DU) restrict

xR

lRxR or GPSDkNiXR=OmNiXNi(t) W, mod 4 •strict

NtxR Π

RxR 36 200901654 f &lt;(t) du〇 = 0 0&lt;(〇 0 0 0 0 0 ··· In Equation 35 and ,, Π

k RxR Ice (7) and each of them have the same meanings as in the program 34. (8) The eighth embodiment relates to a transmitter for performing phase shift precoding. Generally, a communication system includes a transmitter and a receiver. In this case, the transmitter and receiver can be considered as a transceiver. In order to clarify the feedback function, one of the parts for transmitting general data is a transmitter, and is used to transmit the feedback data to other parts of the transmitter. In the downlink, the transmitter can be part of a Node B, or the receiver can be part of a User Equipment (UE). In an uplink, the transceiver can also be part of the UE, or the receiver can be a part of Node B. Node B can include a complex receiver and a complex transmitter. Also, the user equipment (UE) may also include a plurality of receivers and a plurality of transmitters. Figure 7 is a block diagram showing a SCW OFDM transmitter based on a phase shift precoding scheme in accordance with the present invention. Figure 8 is a block diagram showing a MCW OFDM transmitter in accordance with the present invention. Referring to Figures 7 and 8, channel encoders 510 and 610, interleavers 520 and 620, IFFT (Fast Fourier Transform) units 550 and 650, analog converters 560 and 660, etc., and those of Figure 1 The same, so for the convenience of description 37 200901654, a detailed description thereof will be omitted herein. Only the precoder 540 and the 640 ° precoder 540 will include a precoding matrix decision module 541 and a precoding module 542. The precoder 640 includes a precoding matrix decision module 64 1 and a precoding module 642. The precoding matrix decision module (541, 641) is configured according to the first group of equations 12, 14 and '15, or the second group of equations 20 and 21, Q and determines a phase shift precoding matrix. A detailed method for determining the precoding matrix has been described in the second to fourth embodiments, and thus the detailed description thereof will be omitted herein for convenience of description. The phase-shifted precoding matrix based on the first group of Equations 12, 14 and 15 or the second group of Equations 20 and 21 can be changed - a precoding matrix for preventing inter-subcarrier interference, one of the diagonals in time The phase angle and/or unit matrix of the matrix is shown in Equation 18. The precoding matrix decision module (541, 641) may select at least one of the precoding matrix and the unit matrix based on the feedback information of a receiving end. In this case, preferably, the feedback information may include a matrix index of a predetermined codebook. (The J precoding module (542, 642) multiplies an OFDM symbol by the determined phase shifted precoding matrix' and performs precoding on the multiplied result. In general, the individual components of a receiver have a transmitter This level • the opposite function. A receiver in a MIMO-OFDM system using a phase-shifted precoding matrix will be described. » First, the receiver receives the pilot signal from the transmitter and uses the received bow signal to achieve ΜΙΜΟChannel information. And then, the receiver multiplies the phase-shifted precoding matrix by the MlM channel information to achieve the equal 欵38 200901654

Mmo channel information. The phase shift precoding can be determined based on at least one of spatial multiplex rate (or level) information and precoding matrix information from the wheel. The receiver can use the equivalent mim channel information and signal vector received from the transmitter to retrieve the data signal. And the channel decoding system performs error detection/correction for the captured data signal and transmits the data. According to the ΜΙΜΟ receiving scheme or may include additional decoding operations. Finally, the receiver that can be repeatedly used by the transmitter to transmit the pre-description operation can be adapted, thus, the receiving scheme

Further details of the further details based on phase-shifted precoding without modification to conform to the receiving party are made according to the invention. ", the terminology is determined in accordance with the function of the present invention [and can be selected according to the technical drawing or the usual implementation of the terminology ..., preferably the above 2 is based on the disclosure of the present invention. Those skilled in the art will appreciate that modifications and variations can be made without departing from the invention. (4) 2 Various modifications and variations of the present invention are intended to cover the scope of the appended claims and the present invention. Explain that the phase-shift pre-coding of the problem of the present issue is solved by the conventional method: implementing effective communication. The phase-shifting pre-programming is generalized or extended, and the design of a transceiver has been simplified or communicated. </ RTI> </ RTI> </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; The scope and spirit of the invention disclosed. [Simplified illustration]

The accompanying drawings are included to provide a In the drawings: Figure 1 is a block diagram of an OFDM system equipped with a multi-transmission/reception (Tx/Rx) antenna, and Figure 2 illustrates a transmission end of a system based on a conventional cyclic delay diversity (CDD) scheme. Block diagram; Figure 3 illustrates a block diagram of the transmission end of the system based on the conventional phase shift diversity (PSD) scheme; Figure 4 illustrates a block diagram of the transmission Is based on the precoding scheme. Figure 5 is a block diagram showing the main components of a transmitter for performing a phase-shifted precoding scheme according to the present invention; Figure 6 is a diagram illustrating the phase shifting precoding or phase shifting diversity according to the present invention. FIG. 7 is a block diagram showing an SCW OFDM transmitter based on a phase shift precoding scheme according to the present invention; and 40 200901654 FIG. 8 is a block diagram showing an MCW OFDM carrier according to the present invention. . [Main Element Symbol Description] 101 Channel Encoder 103 Mapper 105 Tandem to Parallel (S/P) Converter 105 ΜΙΜΟ Encoder 109 ΜΙΜΟ Decoder 111 Parallel to Serial (P/S) Converter 113 Demapper 115 Channel decoder 510 channel encoder 520 interleaver 530 mapper 540 precoder 541 precoding matrix decision module 542 precoding module 550 IFFT (fast Fourier inverse conversion) unit 560 analog converter 610 channel encoder 620 interleaving 630 Mapper 640 Precoder 641 Precoding Matrix Decision Module 642 Precoding Module 650 IFFT (Fast Fourier Transform) 660 Analog Converter

Claims (1)

200901654 X. Patent application scope: 1. A method for transmitting a data in a multi-input multi-output (MIMO) system using a plurality of subcarriers, the method comprising the following steps: a precoding matrix as one of a phase shifting precoding matrix. Part; determining a first diagonal matrix for a phase shift as part of the phase shifting ζ\precoding matrix; determining a unit matrix as a portion of the phase-shifted precoding matrix; and precoding by multiplying the phase-shifted precoding matrix by a transmission symbol per resource, wherein the phase-shifting precoding matrix is obtained by using the precoding matrix The first diagonal matrix and the unit matrix are multiplied to determine. 2. The method of claim 1, wherein: (J the precoding matrix is selected to be cyclically repeated in a first codebook according to a resource index (k). 3. The method of claim 3, wherein: the precoding matrix is selected to be cyclically repeated in a first codebook according to the resource index repeated in a predetermined unit. 4. The method of claim 3, wherein : 42 200901654 The predetermined unit is determined by considering a spatial multiplex rate. 5. The method of claim 2, wherein: the precoding matrix selects C 6 from a portion of the first codebook The method of claim 2, wherein: the precoding matrix is selected from a second codebook comprising a portion of the first codebook. 7. The method of claim 1 The method, wherein: the phase shifting precoding matrix is represented by the following program: [Equation] 0φ 0 m VtXR J Ο e • · :· Lu, Ο ο :.: 藤 藤 οο.· jdRk J Μ where 'w The precoding matrix, iVt system τχ The number of lines is the unit matrix, rk" is a resource index, 0i (i 1, 2, 3, 4) is a phase angle value, and R is a spatial multiplex rate. 8. As claimed in the patent scope The method of the present invention further includes the steps of: determining a second diagonal matrix for a phase shift as part of the phase shifting precoding matrix, wherein 43 200901654 the phase shifting precoding matrix is The second diagonal matrix, the precoding matrix, the first diagonal matrix, and the unit matrix are multiplied together. 9. The method of claim 2, wherein: the precoding matrix is Based on the feedback information received from a receiving end, it is selected from the first codebook. 10. A transceiver for transmitting a data in a multiple input multiple output (MIMO) system using a plurality of subcarriers, the transceiver comprising: a precoding matrix decision module that determines a precoding matrix As a part of a phase shift precoding matrix, a first diagonal matrix for a phase shift is determined as a part of the phase shift precoding matrix, and a unit matrix is determined as a part of the phase shift precoding matrix. And determining the phase shift precoding matrix by multiplying the precoding matrix, the first diagonal matrix, and the unit matrix; and A precoding module is configured to precode by multiplying the phase shift precoding matrix by a transmission symbol per resource. 1 1. The transceiver of claim 1, wherein: the precoding matrix is selected to be cyclically repeated in a codebook according to the resource index (k). 1 2 · The transceiver according to claim 10, wherein: 44 200901654 the precoding matrix is operated by an analog to operate an index of a corresponding subcarrier having a codebook size (N) (k) ) selected. 13. The transceiver of claim 10, wherein: the phase shifting precoding matrix is represented by the following program: [Equation] e X QP·: 0 he... ο .6 Tfi... ο 0 :...3⁄4 Λ where ' is the precoding matrix, iVt is the number of τ χ antennas, is the unit matrix, "k" is a resource index, 0i (i 1, 2, 3, 4) is a Phase angle value, and R is a spatial multiplex rate. 14. The transceiver of claim 10, wherein: the precoding matrix decision module determines a second diagonal matrix for a phase shift as part of the phase shift precoding matrix, wherein The phase shift precoding matrix is determined by multiplying the second diagonal matrix, the precoding matrix, the first diagonal matrix, and the unit matrix. The transceiver of claim 11, wherein: the precoding matrix is based on feedback information received from a receiving end. 200901654 Selected. 16. The transceiver of claim 15, wherein: the feedback information comprises a precoding matrix index (ΡΜΙ) associated with the codebook (〇). A method for receiving a data in a multiple input multiple output (MIMO) system of subcarriers, the method comprising the steps of: determining a precoding matrix as part of a phase shifting precoding matrix; determining one for a phase shift a first diagonal matrix as part of the phase shifting precoding matrix; determining a unit matrix as part of the phase shifting precoding matrix; and transmitting a symbol per resource based on the phase shifting precoding matrix Decoding, wherein the phase shifting precoding matrix is determined by multiplying the precoding matrix, the first diagonal matrix, and the unit matrix. 18. The method of claim 17, wherein: the precoding matrix is selected to cyclically repeat in a codebook based on the resource index. 19. A method for transmitting a data in a system using multiple input multiple output (ΜΙΜΟ) 46 200901654 of a plurality of subcarriers, the method comprising the steps of: determining a precoding matrix as a phase shifting precoding matrix Part of: determining a rotation matrix as a part of the phase shift precoding matrix according to a spatial multiplex rate; and precoding by multiplying the phase shift precoding matrix by a transmission symbol per resource, wherein the phase shift The precoding matrix is determined by multiplying the precoding matrix and the rotation matrix. 20. The method of claim 19, wherein: the precoding matrix is selected from a portion of a first codebook. 2. The method of claim 19, wherein: the precoding matrix is selected from a second codebook comprising a portion of a first codebook. 22. The method of claim 21, wherein: the second codebook is determined by considering at least one of: spatial multiplex rate, channel coding rate, and retransmission. 23. The method of claim 19, wherein: the rotation matrix comprises a product of one phase diagonal matrix and one unit matrix for one phase shift. 47. The method of claim 19, wherein: the precoding matrix is selected to cyclically repeat in a first codebook according to the resource index repeated in a predetermined unit. The method of claim 24, wherein: the predetermined unit is determined in consideration of the spatial multiplex rate. 26. The method of claim 19 or 20, further comprising the steps of: determining a diagonal matrix for a power control as part of the phase shifting precoding matrix, wherein the phase shifting pre- The coding matrix is determined by multiplying the precoding matrix, the rotation matrix, and the diagonal matrix for a power control. 48