WO2005055483A1 - Appareil de radiocommunication et procede de radiocommunication - Google Patents

Appareil de radiocommunication et procede de radiocommunication Download PDF

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Publication number
WO2005055483A1
WO2005055483A1 PCT/JP2004/018031 JP2004018031W WO2005055483A1 WO 2005055483 A1 WO2005055483 A1 WO 2005055483A1 JP 2004018031 W JP2004018031 W JP 2004018031W WO 2005055483 A1 WO2005055483 A1 WO 2005055483A1
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Prior art keywords
signal
matrix
column vector
wireless communication
antenna
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PCT/JP2004/018031
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English (en)
Japanese (ja)
Inventor
Atsushi Ohta
Takeshi Onizawa
Takafumi Fujita
Wenjie Jiang
Satoshi Kurosaki
Daisei Uchida
Yusuke Asai
Syuji Kubota
Satoru Aikawa
Takatoshi Sugiyama
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Nippon Telegraph And Telephone Corporation
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Priority to JP2005515985A priority Critical patent/JP4188371B2/ja
Publication of WO2005055483A1 publication Critical patent/WO2005055483A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L25/00—Baseband systems
    • H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
    • H04L25/0202—Channel estimation
    • H04L25/0224—Channel estimation using sounding signals
    • H04L25/0228—Channel estimation using sounding signals with direct estimation from sounding signals

Definitions

  • the present invention uses the same frequency channel, transmits independent data from a plurality of different transmitting antennas, receives signals using a plurality of receiving antennas, and uses a transfer function matrix between the respective transmitting and receiving antennas.
  • High-speed wireless access system and wireless communication method in a high-speed wireless access system that realizes wireless communication by demodulating data at the receiving station side, especially the 2.4-GHz band or 5-GHz band high-speed wireless access system ( The present invention relates to a wireless communication device and a wireless communication method that are used to increase the transmission speed of a wireless LAN system and realize good transmission characteristics while suppressing the circuit scale.
  • MIMO Multiple-Input Multiple-Output
  • This MIMO technology is that the transmitting station transmits different independent signals on the same channel from a plurality of transmitting antennas, and the receiving station receives the signals using the same plurality of antennas.
  • a transfer function matrix between the Z receiving antennas is obtained, and using this matrix, the transmitting station estimates independent signals transmitted from each antenna, and reproduces the data.
  • N transmission signals are transmitted using N transmission antennas and signals are received using M antennas.
  • NXM transmission paths between the antennas of the transmitting and receiving stations, and the transfer function when transmitted from the i-th transmitting antenna and received by the j-th receiving antenna is h, and this is (j, i)
  • H The matrix of N rows and M columns as components is denoted as H.
  • a transmission signal from the i-th transmission antenna is denoted by t, and a sequence of (t, t, t,---t) as a component.
  • the tuple is Tx
  • the received signal at the j-th receiving antenna is a column j 1 2 3 M with components (r, r, r, r, ⁇ )
  • Torr is denoted by n.
  • Rx is a received signal vector
  • H is a transfer function matrix
  • Tx is a transmitted signal column vector
  • ⁇ is a thermal noise column vector
  • Equation 1 the inverse matrix H- 1 of the transfer function matrix is obtained, and a process of multiplying the inverse matrix H- 1 on both sides of the equation is performed. As a result, the following equation is obtained.
  • H- 1 is the inverse matrix of the transfer function matrix
  • Rx is the vector of the received signal
  • H is the transfer function matrix
  • Tx is the column vector of the transmitted signal
  • n is the column vector of the thermal noise.
  • N the number of signal points (hereinafter, referred to as N) that can be taken by a signal transmitted from one antenna is determined. All N antennas
  • the signal is transmitted to all candidates (N ⁇ kinds in total) that Tx can take as a signal
  • the received signal is predicted, and the one closest to the actual received signal is selected as the signal point with the highest estimation accuracy. That is, assuming that the k-th transmission signal candidate is represented by ⁇ x [k] , a value of k that minimizes the Euclidean distance E defined by the following equation is selected.
  • M H denotes a matrix that is a Hermitian conjugate of the matrix M with respect to the matrix M (or vector M).
  • FIG. 7 shows a configuration of a transmitting unit of a first wireless station (transmitting side wireless communication device) in the related art.
  • 100 is a data division circuit
  • 101-1—101—4 is a preamble assignment circuit
  • 102—1—102—4 is a modulation circuit
  • 103—1—103—4 is a radio section
  • — 4 indicates the transmitting antenna.
  • a transmitting station transmits data of four systems using four transmitting antennas will be described.
  • data division circuit 100 divides the data into four systems.
  • the data of the first system is input to the preamble adding circuit 101-1 and is input to the modulation circuit (Chi) 102-1 with the preamble signal added.
  • the modulation circuit performs a predetermined modulation, and the modulated signal is converted to a radio frequency by radio section 103-1 and transmitted from transmission antenna 104-1.
  • the data of the second system goes through 101-2-104-2
  • the data of the third system goes through 101-3-3-104-3
  • the data of the fourth system goes through 101-4-1-104-4. Each is sent individually.
  • FIG. 8 shows a configuration of a receiving unit of a wireless communication device using the MLD method in the related art.
  • 111-1 111-4 is a receiving antenna
  • 112-1 112-4 is a radio section
  • 113 is a channel estimation circuit
  • 114 is a received signal management section
  • 115 is a transfer function matrix management circuit
  • 116 is a replica signal generation.
  • Circuit 117 is a transmission signal generation circuit
  • 118 is a Euclidean distance calculation circuit
  • 119 is a selection circuit
  • 120 is a data synthesis circuit.
  • the first receiving antenna 111-1 to the fourth receiving antenna 1114 individually receive a received signal.
  • the received signal is input to the channel estimation circuit 113 via the radio section 112-1 to 112-4.
  • the transfer function between each transmitting antenna and the receiving antenna is obtained here by the channel estimation circuit 113.
  • the acquired information h of each transfer function is managed by the transfer function matrix management circuit 115 as a transfer function matrix H.
  • the data signal following the preamble signal is input to the reception signal management circuit 114 for each symbol.
  • the reception signal (r r ) is input to the reception signal management circuit 114 for each symbol.
  • the transmission signal generating circuit 117 as all signals pattern which can be outputted from the transmitting antenna, the N N kinds of transmission signal candidates ⁇ S [k] ⁇ to generate a (l ⁇ k ⁇ N N) .
  • the Jamaica signal generation circuit 116 calculates the product of the signal S [k] input from the transmission signal generation circuit 117 and the transfer function matrix H managed by the transfer function matrix management circuit 115, HXS [k], and calculates the Euclidean distance
  • the circuit 118 calculates the Euclidean distance between the result and the received signal vector Rx managed by the received signal management circuit 114.
  • the above Euclidean distance calculation processing is performed for all k values (total N N times). In the selection circuit 119, these max
  • the one having the shortest Euclidean distance is selected, and the signal having the highest estimation accuracy is determined to be a transmission signal.
  • These data are processed continuously over a plurality of symbols. After receiving a series of data, the data synthesis circuit 120 reconstructs the data and outputs the data.
  • FIG. 9 shows a transmission flow of the first wireless station (the wireless communication device on the transmission side) according to the related art.
  • the transmitting station divides the data into N data sequences (step S101), and a preamble signal is added to each of these signals (step S102).
  • the modulation process is performed individually for each (step S103).
  • the modulated signal is converted to a radio frequency by the radio unit, and the signal is transmitted (step S104).
  • FIG. 10 shows a reception flow of a wireless communication device using the MLD method in the conventional technology.
  • the receiving station Upon receiving the wireless packet (step S110), the receiving station detects a preamble (step S111) and performs channel estimation (step S112). Here, all transfer functions between each transmitting antenna and receiving antenna are acquired.
  • the signal received subsequent to the preamble signal is managed as a received signal vector Rx having a received signal r at each receiving antenna as a component for each symbol (step S113). N as all signal patterns that can be output from
  • the product HXS [k] is calculated (step S115, the Euclidean distance to the received signal Rx is calculated (step S116). This processing S114—S116 is actually performed N N times in total.
  • the calculated Euclidean distance for each of the N N transmission signal vectors is obtained.
  • the signal estimation transmitted from is determined (step S118). If the received data continues, the process returns to the processing step S113, and the processing steps S113 to S119 are repeated.
  • the reception data is completed (step S119), the reception data of each series is reconstructed, and the data on the transmission side is reproduced to output the data (step S120).
  • the biggest problem of the MLD method is that the calculation processing for calculating the Euclidean distance is reduced to N N times.
  • the challenge is to reduce the complexity.
  • Non-Patent Document l S. Kurosaki et.al., "A SDM-COFDM Scheme Employing a Simple Feed-Forward Inter-Channel Interference Canceller for MIMO Based Broadband Wireless LANs", IEICE TRANS. COMMUN., Vol.E86B. l January, 2003
  • Non-Patent Document 2 A. van Zelst et.al, "Space Division Multiplexing (SDM) for OFDM Systems", Proc.VTC2000 Spring, Vol.2, pp.1070-1074
  • an object of the present invention is to provide a wireless communication apparatus which can realize a good characteristic and realize a realistic circuit scale and computation amount when performing wireless communication using MIMO technology. And a wireless communication method.
  • a wireless communication apparatus includes: a first wireless station including N (N is an integer greater than 1) or more first antenna groups; A second radio station having a number of second antenna groups (greater than 1 and an integer), wherein the first radio station divides the input user data into N systems, Means for giving an individual known pattern signal to the data divided into systems to generate a first signal sequence of N systems, and simultaneously using the N first antenna groups at the same frequency. Means for superimposing and transmitting a first signal sequence, the wireless communication device in a wireless communication system,
  • the transmission between the antenna and the j-th antenna in the second antenna group Means for obtaining the transfer function h,
  • a predetermined number of signal points are selected from the values of the components of the column vector Tx 'and signal points that can be taken as transmission signals in the vicinity thereof, and these are combined, and candidates for the transmission signal transmitted from the first antenna group are selected.
  • one of the candidate signals is selected, and transmitted from the first wireless station based on the selected signal.
  • the means for generating a plurality of types of transmission signal candidate signals transmitted from the first antenna group includes:
  • N signal points including t (N is an integer less than or equal to N) including t, and the signal of the Nth component
  • Means for generating a plurality of types of signals that are candidates for the transmission signal are candidates for the transmission signal.
  • the means for reproducing and outputting the user data transmitted from the first wireless station includes:
  • Means for calculating a product of the transfer function matrix H and the column vector that is, a column vector given by H X S [k];
  • the means for obtaining the first approximate column vector Tx includes:
  • Means for calculating the product of the inverse matrix and the matrix ⁇ ⁇ ⁇ that is, a matrix of ⁇ rows and ⁇ columns ( ⁇ ⁇ X ⁇ ) 1 X ⁇ ⁇ ,
  • the received signal actually received by the m-th antenna of the second antenna group is denoted by!:, And a column vector of M rows in which each component is given by (r, r, r,. (H H XH) — 1
  • the circuit scale for calculating the Euclidean distance diverges exponentially in proportion to the signal type N N max with respect to the number N of superimposed transmission signals.
  • the means for obtaining the first approximated column vector Tx includes:
  • Means for calculating an inverse matrix of the transfer function matrix H that is, a matrix H ⁇ 1 of N rows and N columns, and a received signal actually received by the m-th antenna of the second antenna group as!: If Rx is the column vector of N rows given by (r, r, r, ⁇ 'r), then H— 1 X Rx
  • the means for obtaining the first approximate column vector Tx includes:
  • Means for calculating a matrix of M rows and M columns as a product of these vectors, that is, Y yXyH; and when the preamble signal extends over a plurality of symbols, the value of each component of the matrix Y is transmitted over a plurality of symbols. Means for averaging and replacing this,
  • Means for generating a matrix product of said matrices H H and Y— 1 that is, a matrix H H XY— 1 of N rows and M columns;
  • a received signal actually received by the m-th antenna of the second antenna group is represented by!:, And a column vector of M rows in which each component is given by (r, r, r,. H H XY
  • the MMSE method with better characteristics than the ZF method can be applied when providing initial information for transmission signal point search, and a simple realization method for further improving characteristics can be provided.
  • an orthogonal frequency division multiplexing (OFDM) modulation method using a plurality of subcarriers between the wireless stations may be used! ,.
  • the present invention also provides
  • N is greater than 1 and an integer
  • M is an integer greater than 1
  • a predetermined number of signal points are selected from the values of the components of the column vector Tx 'and signal points that can be taken as transmission signals in the vicinity thereof, and these are combined, and candidates for the transmission signal transmitted from the first antenna group are selected.
  • one of the candidate signals is selected, and transmitted from the first wireless station based on the selected signal. Playing and outputting the user data
  • the step of generating a plurality of types of signals that are candidates for transmission signals transmitted from the first antenna group includes:
  • N is an integer greater than 1) that can be taken as signal points, the first component
  • N signal points including t (N is an integer less than or equal to N) and signal of the second component
  • N (N is an integer less than or equal to N) signal points including t, signal points of the Nth component And select N signal points including t (N is an integer less than or equal to N)
  • the step of reproducing and outputting the user data transmitted from the first wireless station comprises:
  • the step of obtaining the first approximate column vector Tx includes:
  • the received signal actually received by the m-th antenna of the second antenna group is represented by!:, And each component is given by (r, r, r,... ⁇ ). If (H H XH) — 1
  • the step of obtaining the first approximated column vector Tx includes:
  • Each signal at the time of receiving the preamble signal step from the first radio station that generates an N rows and M columns matrix H H to be a Hermitian conjugate of the transfer function matrix H is transmitted at the second antenna group as component Obtaining a column vector y having
  • the preamble signal spans a plurality of symbols, averaging the value of each component of the matrix Y over a plurality of symbols and replacing the averaged value with the average value;
  • a step of generating a matrix product of the matrices H H and Y— 1 that is, an N-by-M matrix H H XY— 1 ;
  • the received signal actually received by the m-th antenna of the second antenna group is represented by!:, And each component is given by (r, r, r,... ⁇ ). If, ⁇ ⁇ ⁇ ⁇ - XR
  • the MMSE method with better characteristics than the ZF method can be applied when providing initial information for transmission signal point search, and a simple realization method for further improving characteristics can be provided.
  • N, ⁇ , ⁇ are determined according to the estimated signal-to-noise ratio of each antenna, and t2 t3 tN
  • the value of the number of transmission signal candidates (N, N, N..., N) is calculated as a matrix ⁇ ⁇ tl t2 t3 tN
  • H may be determined according to the eigenvalue of each antenna.
  • an orthogonal frequency division multiplexing (OFDM) modulation method using a plurality of subcarriers between the wireless stations may be used! ,.
  • OFDM orthogonal frequency division multiplexing
  • the present invention also provides a wireless communication system having the above-described wireless communication device on the receiving side and performing wireless transmission and reception.
  • the candidate group ⁇ S [k] ⁇ of transmission signals to be generated is all signals that can be taken as transmission signals, and the first group of transmission signal estimated values is
  • the first approximate column vector ⁇ ′ of the estimated value of the transmission signal is obtained based on the transfer function matrix ⁇ , and the candidate group is determined based on this. Limit the range of ⁇ S [k] ⁇ .
  • H H , H H XH, ( (H H XH) — ixH 11 is calculated sequentially.
  • the calculation of (H H XH) — ⁇ H XRX is performed to obtain a first approximation Tx of the estimated value of the transmitted signal. The approached ⁇ 'is found, and the transmission signal candidates are generated only in the vicinity of this Tx.
  • the signal type N N The circuit scale for calculating the Euclidean distance exponentially diverges in proportion to the exponential.
  • this is drastically suppressed, and a simplified method for realizing characteristics equivalent to the MLD method while suppressing the circuit scale is achieved. It is possible to provide a simple method.
  • the MMSE method with better characteristics than the ZF method can be applied when providing initial information for transmission signal point search, and a simple realization method for further improving characteristics can be provided.
  • the value of the vector (N 1, N 2, N,..., N) of the number of transmission signal candidates is set to tl t2 t3 tN for each antenna.
  • FIG. 1 is a diagram showing a configuration example of a receiving unit of a wireless communication device according to a first embodiment of the present invention.
  • FIG. 2 is a diagram illustrating a configuration example of a receiving unit of a wireless communication device according to a second embodiment of the present invention.
  • FIG. 3 is a diagram showing a configuration example of a receiving unit of a wireless communication device according to a third embodiment of the present invention.
  • FIG. 4 is a diagram showing a reception flow of the wireless communication device according to the first embodiment of the present invention.
  • FIG. 5 is a diagram showing a reception flow of the wireless communication device according to the second embodiment of the present invention.
  • FIG. 6 is a diagram showing a reception flow of a wireless communication device according to a third embodiment of the present invention.
  • FIG. 7 is a diagram showing a configuration of a transmitting unit of a first wireless station in the related art.
  • FIG. 8 is a diagram showing a configuration of a receiving unit of a wireless communication device using the MLD method according to the related art.
  • FIG. 9 is a diagram showing a transmission flow of a first wireless station in the related art.
  • FIG. 10 is a diagram showing a reception flow of a wireless communication device using the MLD method in a conventional technique. Explanation of symbols
  • the difference between the present invention and the prior art lies in the configuration and processing content of the receiving unit of the wireless communication device.
  • the configuration and processing content of the transmitting unit of the wireless communication device on the transmitting side that is, shown in Figs.
  • the conventional example is common to the present invention. Therefore, hereinafter, the receiving section of the wireless communication device on the receiving side will be described.
  • various embodiments of the present invention will be described with reference to the drawings. In each figure, the product of the matrix is indicated by “ ⁇ ”.
  • FIG. 1 is a diagram illustrating a first embodiment of a wireless communication device according to the present invention, and is a diagram illustrating a configuration example of a receiving unit of the wireless communication device.
  • M 4
  • 1-1-1 1-4 are receiving antennas
  • 2-1 1 2-4 are radio sections
  • 3 is a channel estimation circuit
  • 4 is a received signal management circuit
  • 5 is a transfer function matrix management circuit
  • 6 is a transfer function matrix management circuit.
  • Matrix operation circuits # 1, 7 are matrix operation circuits # 2, 8 are hard decision circuits, 9 is a transmission signal candidate generation circuit, 10 is a replica generation circuit, 11 is a Euclidean distance operation circuit, 12 is a selection circuit, and 13 is data synthesis. The circuit is shown.
  • the first to fourth receiving antennas 11 to 14 individually receive received signals.
  • the received signal is input to the channel estimation circuit 3 via the radio units 2-1 to 2-4.
  • the transfer function between each transmitting antenna and the receiving antenna is acquired here by the channel estimation circuit 3 from the reception state of the predetermined preamble signal given on the transmitting side.
  • the obtained information h of each transfer function is used as a transfer function matrix H in the transfer function matrix management circuit 5.
  • the data signal following the preamble signal is input to the reception signal management circuit 4 for one symbol.
  • the received signal (r, r, r, r, r) of each antenna is
  • the obtained transfer function matrix H is also calculated sequentially as H H (Hermitian matrix of H), H H XH, (H H XH) " ⁇ (H H XH) 1 XH H .
  • the (H H XH) 1 XH H obtained here and the received signal vector Rx managed by the received signal management circuit 4 are integrated by the matrix operation circuit # 2 (7).
  • the signal point Tx (H H XH) — ix HH x Rx obtained here is the first approximation of the estimated value of the transmitted signal, but is generally the constellation of the transmitted signal that takes a discontinuous value due to the thermal noise term. It does not match the point on the lace. Therefore, the hard decision circuit 8 determines a transmission signal point Tx ′ that is close to Tx.
  • the transmission signal candidate generation circuit 9 generates a transmission signal candidate group ⁇ S [k] ⁇ that is close to Tx ′, including the transmission signal point Tx ′ obtained earlier.
  • this candidate The group ⁇ S [k] ⁇ is not related to the hard-decided transmission signal point ⁇ ' ⁇ max All possible max
  • N N is an integer greater than 1) signal points that can be taken as transmission signal points in the component max max
  • N is an integer less than or equal to N
  • N (N is an integer less than or equal to N) signal points including t as signal points and second component signal points
  • N is an integer less than or equal to N
  • N NXN ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ : ⁇ mid mid tl t2 tN is an integer
  • k the k-th (l ⁇ k ⁇ N: k is an integer) column vector mid mid
  • At least one element has a value smaller than N, so that N ⁇ N max mid ma ⁇ ⁇ ⁇ ⁇ .
  • the replica generation circuit 10 performs an integration process of the column vector S [k] generated by the transmission signal candidate generation circuit 9 with the transfer function matrix H managed by the transfer function matrix management circuit 5, Find the estimated value of the received signal when the transmitted signal is S [k]. A distance between this value and an actual received signal managed by the received signal management circuit 4, that is, a Euclidean distance is obtained by the Euclidean distance calculation circuit 11. After performing the same processing on all the transmission signal candidate groups ⁇ S [k] ⁇ , the selection circuit 12 selects the signal S [k] with the shortest Euclidean distance and selects the best.
  • the received signal determined for each symbol in this manner is synthesized for each symbol by the data synthesis circuit 13, and the N-sequence signals are combined into one series, and finally, the data on the transmission side is reproduced. Output.
  • processing to be performed on all of the plurality of transmission signal candidate groups ⁇ S [k] ⁇ is performed by a transmission signal candidate generation circuit 9, a replica generation circuit 10, and a Euclidean distance calculation circuit 11, each of which has one functional block.
  • Each function block has a predetermined number of calculations. You need a function to perform. For example, to reduce processing delays, similar circuits will be implemented in parallel for the number of operations.
  • FIG. 2 is a diagram illustrating a second embodiment of the wireless communication device according to the present invention, and is a diagram illustrating a configuration example of a receiving unit of the wireless communication device.
  • the matrix operation circuit # 1 indicated by 21 and the matrix operation circuit # 2 indicated by 22 all the processes are the same as those shown in FIG.
  • the matrix operation circuit # 1 (6) in Fig. 1 and the matrix operation circuit # 1 (21) in Fig. 2 the matrix operation circuit # 2 (7) in Fig. 1 and the matrix operation circuit # 2 (22) in Fig. 2
  • the matrix operation circuit # 1 indicated by 21
  • the matrix operation circuit # 2 indicated by 22 all the processes are the same as those shown in FIG.
  • the matrix operation circuit # 2 (7) in Fig. 1 and the matrix operation circuit # 2 (22) in Fig. 2 Are different from each other in the content of the processing performed internally.
  • the values of ⁇ and ⁇ are different, and the transfer function matrix ⁇ is a non-square matrix. For this reason, the matrix was converted to a square matrix by using the product of the Hermitian matrices ⁇ ⁇ and ⁇ of the transfer function matrix ⁇ . However, if the original matrix is a square matrix, such processing is unnecessary, and the matrix operation circuit # 1 (21) finds the inverse matrix ⁇ - 1 of the transfer function matrix ⁇ , and the matrix operation circuit # 2 ( 22) Then take the product of this inverse matrix and the received signal vector Rx! ,.
  • the conventional ZF method is used as the first approximation of the estimated value of the transmission signal.
  • other methods can be selected as the first approximation of the estimated value of the transmission signal.
  • the MMSE (Minimum Mean Square Error) method is one example.
  • FIG. 3 is a diagram illustrating a third embodiment of the present invention, and is a diagram illustrating a configuration example of a receiving unit of a wireless communication device.
  • a matrix operation circuit # 1 indicated by 31 and a row indicated by 32 Except for the received signal management circuits indicated by the column operation circuits # 2 and # 33, the processing contents are all the same as those shown in FIG. Also, the matrix operation circuit # 1 (6) of FIG. 1 and the matrix operation circuit # 1 (31) of FIG. 3, the matrix operation circuit # 2 (7) of FIG. 1, and the matrix operation circuit # 2 (31) of FIG.
  • the reception signal management circuit 33 has a function of extracting the preamble signal y from the received signals and inputting the extracted signal to the matrix operation circuit # 1 (31), in addition to the conventional function.
  • the matrix operation circuit # 1 (31) obtains the transfer function matrix H force H H obtained by the transfer function matrix management circuit 5 and, with respect to the preamble signal y input from the reception signal management circuit 33, its Hermitian conjugate. Generate a new vector y H and perform yXy H operation. If preamplifier Le signal is plural symbols, as an average value in the plurality of symbols, or as the raw value in the case of 1 symbol, to obtain a matrix Y as the average value of Yxy H.
  • the inverse matrix Y— and the matrix H H XY— 1 are sequentially calculated.
  • the above is the function of the matrix operation circuit # 1 (31).
  • the matrix operation circuit # 2 (32) the matrix product of the received signal Rx supplied from the matrix operation circuit # 1 (3 1) and H H XY _1 acquired from the received signal management circuit 33 operation I do.
  • This H H XY—XRx is the first approximation of the estimated value of the transmission signal in the present embodiment.
  • the received signal is actually received by the m-th antenna of the second antenna group, and each component is given by (r, r, r,... ⁇ ). ⁇ ⁇ ⁇ ⁇ 1 1 m 1 2 3 M
  • N signal points including t (N is an integer less than or equal to N) and signal of the second component
  • N (N is an integer less than or equal to N) signal points including t, signal points of the Nth component
  • the product of the transfer function matrix H and the column vector that is, the column vector given by H X S [k] is calculated. Also, the distance between the signal points between the column vector HXS [k] for each column vector S [k] and the actual received signal vector Rx is calculated, and the transmission distance that minimizes the signal point distance among all k is calculated. Select signal point S [k] and combine each element of this selected column vector
  • the matrix (H H XH) —E is used as the estimated value (first-order approximation) of the transmission signal. If it is possible to find the force (Equation 1) showing the one using ⁇ or H_1 or the solution (or approximate solution) of the equation omitting the thermal noise term in this equation, other means may be used. I don't know.
  • FIG. 4 shows a reception flow in the wireless communication device according to the first embodiment of the present invention (see FIG. 1).
  • the transmission signal candidate group ⁇ S [k] ⁇ generated in processing step S114 is all signals that can be taken as transmission signals, and the first approximation ⁇ , ⁇ ⁇ ⁇ , ⁇ ⁇ ⁇ ⁇ , ( ⁇ ⁇ ⁇ ⁇ ) " ⁇ ( ⁇ ⁇ ) based on the transfer function matrix ⁇ ⁇ after the channel estimation processing (step S3).
  • X ⁇ ) 1 X ⁇ ⁇ is sequentially calculated (step S4).
  • step S5 When the received signal of a certain symbol is Rx (step S5), the calculation of (H H XH) 1 XH H X Rx is performed (step S6). 1 Approximate Tx 'is calculated (step S7).
  • the transmission signal is generated only in the vicinity of the first approximation Tx of the estimated value of the transmission signal (step S8). Subsequent processing steps S10—S15 This is the same as the processing in the conventional processing steps S116 to S121 shown in FIG.
  • FIG. 5 is a diagram showing a reception flow in the wireless communication apparatus according to the second embodiment of the present invention (see FIG. 2).
  • the only difference from the reception flow shown in FIG. 4 is that the processing steps S4 and S6 shown in FIG. 4 are replaced by the processing steps S24 and S26 in FIG.
  • FIG. 6 is a diagram illustrating a reception flow of the wireless communication device according to the third embodiment of the present invention (see FIG. 3).
  • the difference from the reception flow shown in FIG. 4 is that the processing step S4 in FIG. 4 is replaced by the processing steps S45 to S47 in FIG. 6, and the processing step S6 is replaced by the processing S49. Further, the contents of each processing step correspond to the processing described in FIG.
  • the number of points is limited to five, ie, the number of points up to one proximity, the amount of calculation can be reduced to 5 N. Furthermore, when limited to 9 points including up to the second proximity, the operation amount is suppressed to 9 N.
  • the calculation amount in the conventional method 16,777,216 times, 6,561 times in the case of 9 N, 625 times in the case of 5 N, in the case of 4 N becomes 256 times. In this way, the amount of calculation can be dramatically reduced.
  • the value of the number of transmission signal candidates (N 1, N 2, N 2 '1, ⁇ ) for each transmission antenna is the same as tl t2 t3 tN, but may be different for each antenna.
  • N M
  • the estimated value of the signal-to-noise ratio of the signal corresponding to the i-th transmitting antenna can be obtained by the following equation.
  • g represents the j-th component of the inverse matrix of the transfer function matrix H.
  • the signal to noise ratio
  • N is set to a small value for such an antenna, and N is set to a large value for a poor antenna with a small signal-to-noise ratio. I do.
  • the eigenvalue of H H XH with respect to the transfer function matrix H is often used as an index indicating the reception status of the signal corresponding to each transmitting antenna.
  • the characteristic is good when the absolute value of the eigenvalue is large! / ⁇ , and the characteristic is bad when the absolute value of the eigenvalue is small. Therefore, when the absolute value of the eigenvalue is large, N is set to a small value, and when the absolute value of the eigenvalue is small,
  • the present invention when performing high-efficiency wireless communication using MIMO technology, while achieving the good characteristics of the MLD method, It is possible to greatly reduce the circuit scale and the amount of calculation. As a result, the receiving circuit can be implemented in a one-chip LSI. Also, the reduction in the amount of computation can be expected to have the side effect of directly reducing power consumption.
  • the viewpoint of suppressing the processing delay in a short time is realized as hardware, but the viewpoint of the circuit scale reduction is equivalent to the equivalent processing flow. It is also preferable to realize this by software processing having one.
  • the circuit size is significantly larger than that of the conventional MLD method.
  • the present invention can be applied to a wireless communication device, a wireless communication method, a wireless communication system, and the like.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Radio Transmission System (AREA)

Abstract

Selon l'invention, une première station radio comprenant un premier groupe de N ou plusieurs antennes divise des données utilisateur d'entrée en N systèmes; ajoute des signaux séparés de diagrammes connus auxdites données afin de produire N systèmes de premiers systèmes de signaux; et les transmet simultanément à la même fréquence à l'aide du premier groupe d'antennes. Une seconde station radio comprenant un second groupe de M ou plusieurs antennes reçoit les signaux radio à l'aide des antennes respectives du second groupe d'antennes; et utilise signaux de diagrammes connus ajoutés aux signaux radio, en tant que signaux de référence, pour acquérir une fonction de transfert (hj,i) entre la i-ème antenne du premier groupe et la j-ème antenne du second groupe. Une matrice de fonction de transfert (H), dont le (j,i)-ème élément est la fonction de transfert (hj,i), est utilisée pour obtenir le premier vecteur de séquence approximative (Tx) d'une valeur estimée du signal transmis. Un vecteur de séquence (Tx) est obtenu, dans lequel une décision ferme est accomplie pour chaque point de signal de transmission donné par les éléments du vecteur de séquence (Tx). Hors des points de signal disponibles comme points de signal de transmission pour les composants du vecteur de séquence (Tx), les points de signal situés à proximité de ces composants respectifs sont choisis et combinés les uns avec les autres pour produire une pluralité de types de signaux servant de candidats pour les signaux transmis par l'intermédiaire du premier groupe d'antennes.
PCT/JP2004/018031 2003-12-05 2004-12-03 Appareil de radiocommunication et procede de radiocommunication WO2005055483A1 (fr)

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* Cited by examiner, † Cited by third party
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JP2007300586A (ja) * 2006-05-01 2007-11-15 Tokyo Institute Of Technology Ｍｉｍｏ検波方式
US9178579B2 (en) 2012-03-16 2015-11-03 Fujitsu Limited Wireless device and wireless communication method

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