WO2009119041A1 - Dispositif de communication sans fil, système de communication sans fil et procédé de communication sans fil - Google Patents

Dispositif de communication sans fil, système de communication sans fil et procédé de communication sans fil Download PDF

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Publication number
WO2009119041A1
WO2009119041A1 PCT/JP2009/001184 JP2009001184W WO2009119041A1 WO 2009119041 A1 WO2009119041 A1 WO 2009119041A1 JP 2009001184 W JP2009001184 W JP 2009001184W WO 2009119041 A1 WO2009119041 A1 WO 2009119041A1
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mimo
wireless communication
base station
base stations
data
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PCT/JP2009/001184
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English (en)
Japanese (ja)
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ユーキアン
チェンコウエイ
星野正幸
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パナソニック株式会社
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/022—Site diversity; Macro-diversity
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems

Definitions

  • the present invention relates to a wireless communication apparatus, a wireless communication system, and a wireless communication method applicable to a MIMO (Multiple Input Multiple Output) system that performs communication using a plurality of antennas.
  • MIMO Multiple Input Multiple Output
  • Modern communication systems are expected to provide reliable data transmission for various applications including voice and data applications.
  • Known communication systems for performing point-to-multipoint communication include frequency division multiple access (FDMA), time division multiple access (TDMA), and code division multiple access (CDMA). Code Division Multiple Access), Orthogonal Frequency Division Multiple Access (OFDMA), or possibly other multiple access communication schemes.
  • FDMA frequency division multiple access
  • TDMA time division multiple access
  • CDMA code division multiple access
  • Code Division Multiple Access Code Division Multiple Access
  • OFDMA Orthogonal Frequency Division Multiple Access
  • UE User Equipment
  • broadcasts television broadcasts
  • multicast intra-group broadcast communication
  • Live broadcast television, movies, sports clips, and talk shows can all be broadcast or multicast (hereinafter referred to as broadcast / multicast) from the cellular radio network in addition to the more traditional services offered by this type of network. it can. This actually has the same effect as supplying a cable or satellite channel directly to the user terminal.
  • MBMS Multimedia Broadcast Multicast Service
  • GSM Global System for Mobile Communications
  • UMTS Universal Mobile Telecommunications System
  • E-MBMS Evolved Multimedia Broadcast Multicast Service
  • 3GPP Third Generation Partnership Project
  • Downlink (DL) capacity is an important performance characteristic of cellular communication systems. With increased downlink capacity, for example, more broadcast / multicast channels can be made available to subscribers to improve broadcast communication quality. In cellular communication systems where a fixed frequency range is available, system capacity depends on frequency utilization efficiency. For this reason, when the limited availability of the frequency band is assumed, it is desirable to improve the frequency utilization efficiency of the cellular communication system, including the broadcast / multicast frequency utilization efficiency. In order to eliminate the costs associated with infrastructure infrastructure updates, it is desirable to improve the frequency utilization efficiency of existing infrastructure infrastructures with or without limited changes.
  • MIMO technology has been studied for E-MBMS.
  • the base station (Node B) and the user terminal at the cellular radio communication network site both have a plurality of antennas.
  • SM spatial multiplexing
  • Non-Patent Document 1 and Non-Patent Document 2 disclose that spatial multiplexing technology by MIMO is applied to an MBMS system using SFN to improve frequency use efficiency.
  • An object of the present invention is to provide a wireless communication device, a wireless communication system, and a wireless communication method that can be performed.
  • the present invention provides, as a first aspect, a radio communication device of a base station used in a radio communication system having a plurality of base stations and transmitting data from these base stations to a user terminal.
  • data to be transmitted data having the same information as other base stations is used, and a spatial multiplexing unit that generates a plurality of streams for spatial multiplexing between a plurality of transmission antennas from the data, and the plurality of streams
  • a MIMO encoding unit that performs MIMO encoding using different encoding matrices with other base stations, and a transmission unit that transmits the plurality of encoded data encoded by the MIMO using a plurality of transmission antennas, Are provided.
  • the present invention provides, as a second aspect, the wireless communication apparatus described above, wherein the MIMO encoding unit uses, as the encoding matrix, an encoding matrix obtained by multiplying a different correction matrix from another base station. Includes what you use.
  • the present invention provides, as a third aspect, the wireless communication apparatus described above, wherein an encoding matrix based on a golden code is used as the encoding matrix, and spatial multiplexing in one base station by the spatial multiplexing unit And a base station domain indicating a dimension for obtaining multiplexing diversity between a plurality of base stations by the MIMO encoding unit, and a matrix in which the golden code matrix is applied.
  • the present invention provides, as a fourth aspect, a radio communication device for a user terminal used in a radio communication system having a plurality of base stations and transmitting data from these base stations to the user terminal, wherein the plurality of base stations A receiving unit that receives data of the same information transmitted from each base station by a plurality of receiving antennas, which are MIMO-encoded using mutually different encoding matrices in the station, and a plurality of the received encoded data
  • a wireless communication apparatus comprising: a MIMO detection unit that separates and detects a plurality of streams; and a decoding unit that synthesizes and decodes received data from the detected plurality of streams.
  • the present invention provides, as a fifth aspect, a radio communication system having a plurality of base stations and transmitting data from these base stations to a user terminal, wherein the radio device of the base station is connected to the user terminal.
  • the data to be transmitted the same information data as other base stations is used, and from this data, a spatial multiplexing unit that generates a plurality of streams for spatial multiplexing between a plurality of transmission antennas, and the plurality of streams
  • a MIMO encoding unit that performs MIMO encoding using different encoding matrices with other base stations, and a transmission unit that transmits the plurality of encoded data encoded by the MIMO using a plurality of transmission antennas
  • the wireless communication device of the user terminal comprises: a reception unit that receives data of the same information transmitted from the plurality of base stations by a plurality of reception antennas; A MIMO detector for separating and detecting a plurality of streams from a plurality of encoded data signals, combining the received data from a plurality
  • the present invention provides, as a sixth aspect, a radio communication method in a radio communication system having a plurality of base stations and transmitting data from these base stations to user terminals, the data being transmitted to the user terminals Using the same information data as other base stations and generating a plurality of streams for spatial multiplexing between a plurality of transmission antennas from this data, and for the plurality of streams, other base stations Radio communication having a MIMO encoding step of performing MIMO encoding using different encoding matrices with a station, and a transmission step of transmitting a plurality of encoded data encoded by the MIMO using a plurality of transmission antennas Provide a method.
  • the present invention provides, as a seventh aspect, a radio communication method in a radio communication system having a plurality of base stations and transmitting data from these base stations to a user terminal, wherein the codes differ from each other in the plurality of base stations.
  • a decoding step of combining and decoding received data from the detected plurality of streams is provided, as a seventh aspect, a radio communication method in a radio communication system having a plurality of base stations and transmitting data from these base stations to a user terminal, wherein the codes differ from each other in the plurality of base stations.
  • a radio communication apparatus capable of reducing system capacity loss and improving communication performance.
  • a wireless communication system and a wireless communication method can be provided.
  • FIG. 3 is a block diagram for explaining distributed MIMO encoding processing executed in the SFN base station of the cellular communication system according to the present embodiment.
  • the block diagram which shows the 1st example of a structure of the radio
  • FIG. 1 A more detailed block diagram showing the configuration and operation of the first embodiment
  • a block diagram showing a second example of a configuration of a wireless communication system using a cellular wireless communication network A more detailed block diagram showing the configuration and operation of the second embodiment
  • a block diagram showing a third example of a configuration of a wireless communication system using a cellular wireless communication network A more detailed block diagram showing the configuration and operation of the third embodiment
  • the figure which shows the various examples of the MIMO encoding matrix used for distributed MIMO encoding 6 is a flowchart showing processing for performing distributed MIMO encoding in each base station according to the embodiment of the present invention.
  • the wireless communication apparatus the wireless communication system, and the wireless communication method according to the present invention
  • MBMS broadcast / multicast is performed in a cellular wireless communication network, and a plurality of base stations transmit the same frequency.
  • adopted SFN which transmits the same signal is shown.
  • spatial multiplexing is performed using MIMO for communication between each base station and the user terminal.
  • This embodiment relates generally to remote communication, and more particularly to a method and apparatus for broadcast / multicast from a cellular radio communication network, and a manufacturing clause.
  • the system and method disclosed in the present embodiment provide a method for transmitting data from a plurality of base stations or cells in a cellular communication system, thereby compensating for system capacity caused by spatial correlation and improving frequency utilization efficiency. It addresses the need for technology to make it happen.
  • distributed MIMO coding is applied to a plurality of base stations to improve diversity between data streams transmitted from different base stations, and subsequently compensate for capacity loss due to spatial correlation.
  • a method is provided that addresses the above needs. The method includes assigning different MIMO encodings to each of a plurality of base stations. In each base station, frequency utilization efficiency is improved using spatial multiplexing technology.
  • MIMO encoding is applied to a plurality of data streams by multiplying an encoding matrix as an encoding weight, and then transmitted from a plurality of transmission antennas.
  • a cellular communication system includes a plurality of cells each having one base station.
  • Each base station has at least two transmission antennas in one base station.
  • Each base station has means for introducing MIMO coding using multiple spatial data streams.
  • the means for introducing MIMO coding using a plurality of spatial data streams includes multiplication of a plurality of spatial data streams by a MIMO coding matrix.
  • the MIMO coding matrices used in each base station are different from each other in order to provide multiplexing diversity between data streams transmitted from each of a plurality of cells / base stations.
  • a configuration having one cell for each base station is shown, but a configuration having a plurality of cells in one base station can also be adopted.
  • cell although expressed as “cell” here, it may be referred to as “sector”.
  • a method called distributed MIMO coding for transmitting multiple data streams from multiple base stations.
  • This method includes the following processes. 1. A different MIMO encoding matrix is allocated to each of the plurality of base stations. The MIMO coding matrix is designed to provide multiplexing diversity between each of a plurality of base stations. 2. Multiple data streams are encoded with the assigned MIMO encoding matrix by multiplying the data stream by a matrix at each of the plurality of base stations. 3. An encoded data stream is transmitted from each of a plurality of base stations via a plurality of transmission antennas.
  • SFN is a wireless communication network that operates several transmitters at the same frequency. Several transmitters can be synchronized to eliminate or reduce interference. That is, the same signal is transmitted from several transmitters. With the same transmission power allocation, MIMO technology can increase the frequency utilization efficiency of wireless communication. MIMO uses multiple spatially diverse transmit antennas at the base station and multiple spatially diverse receive antennas at the user terminal.
  • FIG. 1 is a diagram illustrating a configuration example of a communication system that performs signal transmission using MIMO from two base stations to user terminals in an SFN. From the first base station (BS1) 102 and the second base station (BS2) 106, two data streams that are MIMO-encoded with different MIMO encoding matrices are transmitted to the user terminal (UE) 110 at the same frequency. To do.
  • two physical transmission channels ie a channel matrix between the first base station 102 and the user terminal 110 H k1 and a channel matrix H k2 between the second base station 106 and the user terminal 110 exist. That is, the data is transmitted from the first base station 102 to the user terminal 110 via the MIMO channel 1, and is transmitted from the second base station 106 to the user terminal 110 via the MIMO channel 2.
  • Each of these channels is exposed to channel conditions such as delay, interference, noise, multipath fading, dispersion, and distortion. Due to the spatial diversity of the transmit and receive antennas, the combined effect of these conditions is generally different for each of these channels.
  • open-loop MIMO technology that is, spatial multiplexing
  • a plurality of transmission antennas are used in MIMO, as one method of adopting MIMO, a plurality of streams are transmitted from a plurality of antennas of the same base station (cell).
  • the received signal-to-noise ratio (SNR) at the user terminal can be very high.
  • SNR signal-to-noise ratio
  • the SNR is typically above 14 dB for 95% of users.
  • this type of high SNR makes it possible to use open-loop (no feedback used to set the encoding matrix) MIMO as an additional option for E-MBMS.
  • two streams S 1 and S 2 are transmitted to two antennas 104A (Ant1), 104B (Ant2) and a second base in the first base station 102.
  • Two antennas 108A (Ant1) and 108B (Ant2) in the station 106 are transmitted simultaneously. Therefore, the received stream in the user terminal 110 is expressed as the following mathematical formula (1).
  • Equation (1) r is a signal vector received from the two antennas 112A and 112B of the user terminal 110, and s is a vector of a data stream transmitted from each base station 102 and 106.
  • H 1 and H 2 are channel matrices between the first base station 102 and the user terminal 110 and between the second base station 106 and the user terminal 110, respectively.
  • w is a vector of noise that affects the transmitted communication signal.
  • the matrices A 1 and A 2 are the squares of the spatial correlation matrices of the first base station 102 and the second base station 106, respectively.
  • the ergodic capacity of the MIMO channel in the exemplary system of FIG. 1 is given by the following formula (2).
  • the combined composite channel matrix H c is expressed by the following formula (3).
  • an antenna unit area (hereinafter referred to as a spatial domain) indicating a dimension for spatial multiplexing in each base station, and a base station indicating a dimension for obtaining multiplexing diversity among a plurality of base stations
  • a base station domain A unit area (hereinafter referred to as a base station domain) is used.
  • a MIMO coding method for generating symbols transmitted via each antenna in the spatial domain is used, and different codewords are used in different base stations.
  • a MIMO coding method for generating symbols transmitted via each antenna in the spatial domain is used, and different codewords are used in different base stations.
  • FIG. 2 is a block diagram for explaining distributed MIMO encoding processing executed in the SFN base station of the cellular communication system according to the present embodiment.
  • the communication system according to the present embodiment includes a plurality of cells including a first base station 201 and a second base station 205 as cells configured by base stations. These cells have two transmit antennas at each base station. That is, the first base station 201 has transmission antennas 204A (Ant1) and 204B (Ant2), and the second base station 205 has transmission antennas 208A (Ant1) and 208B (Ant2).
  • the streams S 1 and S 2 are transmitted by the transmission antennas 204A and 204B after the MIMO encoding in the MIMO encoding unit 202 is applied.
  • streams S 1 and S 2 are transmitted by transmitting antennas 208A and 208B after applying MIMO encoding in MIMO encoding section 206.
  • distributed MIMO coding is realized by applying different MIMO coding to the same data stream intended for broadcast / multicast to user terminals in each base station / cell.
  • MIMO coding a data stream S 1, a predetermined correction matrix B 1 to S 2 at the first base station 201, the predetermined at the second base station 205 to the data stream S 1, S 2 the correction matrix B 2 , Each is executed by multiplication.
  • the encoded data streams are transmitted from the antennas 204A and 204B and 208A and 208B to the user terminal, respectively.
  • the data stream s before MIMO encoding, the data stream x 1 transmitted from the first base station 201, and the data stream x 2 transmitted from the second base station 205 are expressed by the following equation (4). .
  • signals of the same content having different codewords are transmitted from each base station by using the distributed MIMO encoding technique, whereby a plurality of base stations are transmitted.
  • Multiplexing diversity between stations is provided and channel capacity improvements using an effective MIMO coding matrix design can be expected.
  • the ergodic capacity of the MIMO channel in the system of this embodiment is given by the following formula (6).
  • the synthesized composite channel matrix H - c is expressed by the following equation (7).
  • the composite channel matrix H - composite channel represented by c can be estimated based on the cell common reference signal and the estimated composite channel may perform linear MIMO detection using.
  • the composite channel matrix H - c that is, H 1 A 1 B 1 and H 2 A 2 B 2 is estimated, and the finally estimated composite channel is determined. Can be used to perform linear MIMO detection.
  • distributed MIMO encoding is achieved by performing MIMO encoding using different encoding matrices between a plurality of base stations, thereby achieving multiplexing diversity among a plurality of base stations. To do. At this time, in the encoding matrix, MIMO encoding is performed with different encoding matrices between the plurality of base stations by multiplying the correction matrices B 1 and B 2 that are different from each other by the plurality of base stations.
  • a golden code is applied to the encoding matrix for MIMO encoding.
  • the golden code encoding matrix is not simply applied to the spatial domain and the time domain as in general MIMO encoding, but is applied to the spatial domain and the base station domain as shown in FIG.
  • the different correction matrices B 1 and B 2 can be multiplied as a result, and multiplexing diversity between a plurality of base stations can be obtained.
  • the same streams S 1 and S 2 are used between a plurality of base stations, and the resource efficiency in the time domain and the space domain is improved.
  • the receiving-side user terminal can perform spatial multiplexing.
  • the plurality of data streams can be easily separated without using complicated processing.
  • the spatial correlation matrix A 1 , A of each base station Without being controlled by 2 , the correction matrices B 1 and B 2 can be separated. For this reason, it is possible to reduce the degree of correlation of a plurality of spatially multiplexed data streams against the influence of spatial correlation, and to extract each data stream, thereby reducing system capacity loss.
  • FIG. 3 is a block diagram showing a first example of the configuration of a wireless communication system using a cellular wireless communication network as the first embodiment of the present invention.
  • the first embodiment is a configuration example in the case where each base station has two transmission antennas and the user terminal has two reception antennas, and each base station performs coding using distributed MIMO coding.
  • 1 shows a wireless communication system for transmitting a received signal to a user terminal.
  • the wireless communication system includes a first base station (BS1) 302, a second base station (BS2) 306, and a user terminal (UE) 310.
  • the first base station 302 and the second base station 306 are provided. Are transmitted to the user terminal 310 at the same frequency by two transmission antennas using two transmission antennas.
  • the first base station 302 has transmission antennas 304A (Ant1) and 304B (Ant2), and the second base station 306 has transmission antennas 308A (Ant1) and 308B (Ant2).
  • the user terminal 310 has receiving antennas 312A (Ant1) and 312B (Ant2). In this case, transmission is performed via the MIMO channel 1 between the first base station 302 and the user terminal 310, and transmission is performed via the MIMO channel 2 between the second base station 306 and the user terminal 310.
  • two data streams S 1 and S 2 are broadcast / multicast from the first base station 302 and the second base station 306 to the user terminal 310 using spatial multiplexing.
  • distributed MIMO coding is applied by assuming predetermined correction matrices B 1 and B 2 expressed by the following equation (8).
  • the signal S 1 and the signal iS 2 are transmitted from the transmission antennas 304 A and 304 B in the first base station 302, and the signal ⁇ iS 1 and the signal ⁇ S 2 are transmitted from the transmission antennas 308 A and 308 B in the second base station 306 simultaneously. Sent from each of the. That is, different signals including the same information are transmitted to user terminals in different base stations / cells, resulting in a diversity effect between the base stations.
  • FIG. 4 is a more detailed block diagram showing the configuration and operation of the first embodiment.
  • the first base station 302 includes a channel encoding unit 411, a symbol mapping unit 412, a spatial multiplexing unit 413, and a MIMO encoding unit 414.
  • the second base station 306 includes a channel encoding unit 421, a symbol mapping unit 422, a spatial multiplexing unit 423, and a MIMO encoding unit 424.
  • the function of the transmission unit is realized by an RF unit (not shown), transmission antennas 304A and 304B, 308A and 308B, and the like.
  • the user terminal 310 includes a channel estimation unit 432, a MIMO detection unit 433, a demultiplexing unit 434, a demapping unit 435, and a decoding unit 436. Also, in the wireless network of the wireless communication system, a MIMO encoding block setting unit 450 is provided in a host control device or the like. In this user terminal 310, the functions of the receiving unit are realized by receiving antennas 312A and 312B, an RF unit (not shown), and the like. In addition, the function of the decoding unit is realized by the demultiplexing unit 434, the demapping unit 435, the decoding unit 436, and the like.
  • the first base station 302 and the second base station 306 perform error correction coding processing on the input bit sequence in the channel encoding units 411 and 421, respectively, and then perform QPSK and 16QAM in the symbol mapping units 412 and 422, respectively. Are modulated by a predetermined modulation method to generate a modulated symbol sequence. Then, the modulated output is distributed as the streams S 1 and S 2 in the spatial multiplexing sections 413 and 423 to perform spatial multiplexing processing, and the MIMO encoding sections 414 and 424 perform MIMO corresponding to the encoding matrix. Perform the encoding process.
  • the encoded data of two outputs subjected to MIMO encoding are transmitted from the transmission antennas 304A and 304B, 308A and 308B, respectively.
  • the encoding matrix in MIMO encoding sections 414 and 424 shall be instructed from MIMO encoding block setting section 450.
  • the indicated encoding matrix can be processed as, for example, the aforementioned correction matrices B 1 and B 2 .
  • User terminal 310 performs channel estimation in channel estimation section 432 using a reference signal among signals observed by receiving antennas 312A and 312B, and outputs the channel estimation result to MIMO detection section 433 as a channel matrix. To do. Similarly, the MIMO detection unit 433 performs MIMO separation processing on the data signal of the signals observed by the receiving antenna using the channel matrix, and detects the separated streams S ⁇ 1 and S ⁇ 2 . Then, the detected signal is rearranged into one symbol series by the demultiplexing unit 434, and the symbol unit demodulation processing is performed by the demapping unit 435. Subsequently, the decoding unit 436 performs error correction decoding processing on the demodulation result, and extracts it as an output bit sequence.
  • distributed MIMO coding can be applied in a 2 ⁇ 2 MIMO system, and multiplexing diversity between a plurality of base stations can be provided.
  • a user terminal on the receiving side can sufficiently separate a plurality of spatially multiplexed signals and can reduce system capacity loss.
  • FIG. 5 is a block diagram showing a second example of the configuration of a wireless communication system using a cellular wireless communication network as the second embodiment of the present invention.
  • the second embodiment is a configuration example in the case where each base station has four transmission antennas and the user terminal has two reception antennas, and each base station performs coding using distributed MIMO coding.
  • 1 shows a wireless communication system for transmitting a received signal to a user terminal.
  • the wireless communication system includes a first base station (BS1) 502, a second base station (BS2) 506, and a user terminal (UE) 510, and the first base station 502 and the second base station 506 are included. Are transmitted to the user terminal 510 at the same frequency using four transmission antennas.
  • the first base station 502 includes transmission antennas 504A (Ant1), 504B (Ant2), 504C (Ant3), and 504D (Ant4)
  • the second base station 506 includes transmission antennas 508A (Ant1), 508B (Ant2), and 508C. (Ant3), 508D (Ant4).
  • the user terminal 510 has receiving antennas 512A (Ant1) and 512B (Ant2). In this case, transmission is performed via the MIMO channel 1 between the first base station 502 and the user terminal 510, and transmission is performed via the MIMO channel 2 between the second base station 506 and the user terminal 510.
  • spatial multiplexing is used to broadcast / multicast two data streams S 1 and S 2 from the first base station 502 and the second base station 506 to the user terminal 510 using four transmission antennas, respectively.
  • two data streams can be detected on the user terminal 510 side using two reception antennas.
  • distributed MIMO coding is applied by assuming predetermined correction matrices B 1 4x2 and B 2 4x2 expressed by the following equation (9).
  • the signals S 1 , iS 2 , S 1 , iS 2 are transmitted from the transmitting antennas 504A, 504B, 504C, 504D in the first base station 502, and simultaneously the signals -iS 1 , -S 2 , -iS 1 , ⁇ S 2 is transmitted from each of the transmission antennas 508 A, 508 B, 508 C, and 508 D in the second base station 506. That is, different signals including the same information are transmitted to user terminals in different base stations / cells, resulting in a diversity effect between the base stations.
  • FIG. 6 is a more detailed block diagram showing the configuration and operation of the second embodiment.
  • the first base station 502 includes a channel encoding unit 611, a symbol mapping unit 612, a spatial multiplexing unit 613, and a MIMO encoding unit 614.
  • the second base station 506 includes a channel encoding unit 621, a symbol mapping unit 622, a spatial multiplexing unit 623, and a MIMO encoding unit 624.
  • the user terminal 510 includes a channel estimation unit 632, a MIMO detection unit 633, a demultiplexing unit 634, a demapping unit 635, and a decoding unit 636.
  • a MIMO coding block setting unit 650 is provided in a higher-level control device or the like in the wireless network of the present wireless communication system.
  • the second embodiment is different from the first embodiment shown in FIG. 4 in that the encoding matrices specified by the MIMO encoding block setting unit 650 are B 1 4x2 and B 2 4x2 , respectively, and the MIMO code
  • the outputs of the combining sections 614 and 624 become four corresponding to the four transmission antennas of each base station. Others are the same as those in the first embodiment, and the description thereof is omitted.
  • distributed MIMO coding can be applied in a 4 ⁇ 2 MIMO system, and multiplexing diversity between a plurality of base stations can be provided. Also in this case, as in the first embodiment, even when the spatial correlation between the transmission antennas in each base station is high, the user terminal on the receiving side can sufficiently separate a plurality of spatially multiplexed signals. , System capacity loss can be reduced.
  • FIG. 7 is a block diagram showing a third example of the configuration of a wireless communication system using a cellular wireless communication network as the third embodiment of the present invention.
  • the third embodiment is a configuration example in the case where each base station has four transmission antennas and the user terminal has four reception antennas, and each base station performs coding using distributed MIMO coding.
  • 1 shows a wireless communication system for transmitting a received signal to a user terminal.
  • the wireless communication system includes a first base station (BS1) 702, a second base station (BS2) 706, and a user terminal (UE) 710.
  • the first base station 702 and the second base station 706 are provided. Are transmitted to the user terminal 710 using the four transmission antennas at the same frequency using the four transmission antennas.
  • the first base station 702 includes transmission antennas 704A (Ant1), 704B (Ant2), 704C (Ant3), and 704D (Ant4)
  • the second base station 706 includes transmission antennas 708A (Ant1), 708B (Ant2), and 708C. (Ant3), 708D (Ant4).
  • the user terminal 710 includes receiving antennas 712A (Ant1), 712B (Ant2), 712C (Ant3), and 712D (Ant4).
  • transmission between the first base station 702 and the user terminal 710 is performed via the MIMO channel 1
  • transmission between the second base station 706 and the user terminal 710 is performed via the MIMO channel 2.
  • spatial multiplexing is used, and four data streams S 1 , S 2 , S 3 , and S 4 are transmitted from the first base station 702 and the second base station 706, respectively, using four transmission antennas. Broadcast / multicast to 710. In this case, the user terminal 710 can detect four data streams using four reception antennas.
  • distributed MIMO coding is applied by assuming predetermined correction matrices B 1 4x4 and B 2 4x4 expressed by the following equation (10).
  • the signals S 1 , iS 2 , S 3 , and iS 4 are transmitted from the transmission antennas 704A, 704B, 704C, and 704D in the first base station 702, and the signals ⁇ iS 1 , ⁇ S 2 , and ⁇ iS 3 are simultaneously transmitted.
  • -S 4 is transmitted from each of the transmission antennas 708 A, 708 B, 708 C, and 708 D in the second base station 706. That is, different signals including the same information are transmitted to user terminals in different base stations / cells, resulting in a diversity effect between the base stations.
  • FIG. 8 is a more detailed block diagram showing the configuration and operation of the third embodiment.
  • the first base station 702 includes a channel encoding unit 811, a symbol mapping unit 812, a spatial multiplexing unit 813, and a MIMO encoding unit 814.
  • the second base station 706 includes a channel encoding unit 821, a symbol mapping unit 822, a spatial multiplexing unit 823, and a MIMO encoding unit 824.
  • the user terminal 710 includes a channel estimation unit 832, a MIMO detection unit 833, a demultiplexing unit 834, a demapping unit 835, and a decoding unit 836.
  • a MIMO coding block setting unit 850 is provided in a higher-level control device or the like in the wireless network of the present wireless communication system.
  • the encoding matrices indicated by the MIMO encoding block setting unit 850 are B 1 4x4 and B 2 4x4 , respectively.
  • the difference is that the outputs of the spatial multiplexing units 813 and 823 are four streams S 1 , S 2 , S 3 , and S 4 .
  • the user terminal side is different in that the output of the MIMO detection unit 833 becomes four streams corresponding to four reception antennas. Since others are the same as those in the first and second embodiments, description thereof will be omitted.
  • distributed MIMO coding can be applied in a 4 ⁇ 4 MIMO system, and multiplexing diversity between a plurality of base stations can be provided.
  • the user terminal on the receiving side sufficiently receives a plurality of spatially multiplexed signals.
  • the system capacity loss can be reduced.
  • One way to extend the coding matrix design from the 2x2 case to the 4x2 or 4x4 case is to use the same coding matrix for the transmission of the first antenna and the second antenna, and these Is to be reused for transmission of the third antenna and the fourth antenna.
  • FIG. 9 is a block diagram showing a fourth example of the configuration of a wireless communication system using a cellular wireless communication network as the fourth embodiment of the present invention.
  • the fourth embodiment is a modification of the first embodiment.
  • the encoding matrix in the MIMO encoding units 414 and 424 does not necessarily need to be dynamically set and changed by instructing from the MIMO encoding block setting unit 450, and adjacent It is also possible to use an encoding matrix set in each base station as a pattern that is random between base stations. Therefore, in the fourth embodiment shown in FIG. 9, the base station 902, 906 is configured to set a coding matrix for MIMO coding in its own station without providing the MIMO coding block setting unit 450.
  • the other components are the same as those in the first embodiment shown in FIG. 4, and a description thereof is omitted here.
  • Each of the first base station 902 and the second base station 906 has a database, and holds MIMO encoded block setting information 960 and 970 in the database.
  • Each of the base stations 902 and 906 acquires correction matrices B 1 and B 2 with reference to its own database after the spatial multiplexing processing in the spatial multiplexing units 413 and 423. Then, using the acquired correction matrices B 1 and B 2 , the MIMO encoding sections 414 and 424 perform MIMO encoding processing, and output the encoded data to the transmission antennas 304A and 304B, 308A and 308B.
  • the correction matrix stored in the database as the MIMO coding block setting information 960, 970 may be a fixed value set so as to realize randomization with the neighboring base station when the base station is installed, It is good also as what can be updated at arbitrary timings. Further, the correction matrix may be uniquely obtained from a base station specific number (base station / cell ID, etc.), or may be uniquely determined from the relation between the number unique to the broadcast / multicast content and the number unique to the base station. It may be required.
  • the base stations 902 and 906 are configured to set the encoding matrix including the correction matrices B 1 and B 2 , the same processing as in the first embodiment is possible. is there.
  • the MIMO coding block setting unit is not provided in the base station, and the MIMO is stored in the database in the same manner as described above.
  • a configuration may be adopted in which encoding block setting information is held, and an encoding matrix is set based on this information to perform MIMO encoding.
  • FIG. 10 is a diagram illustrating various examples of the MIMO encoding matrix used for distributed MIMO encoding.
  • the MIMO encoding matrix used for distributed MIMO encoding is selected using the square deviation.
  • FIG. 10 shows some examples of a certain type of square deviation, but the present invention is not limited to this.
  • a MIMO encoding matrix can be obtained using the same extension described above.
  • FIG. 11 is a flowchart showing processing for executing distributed MIMO encoding in each base station according to the embodiment of the present invention.
  • the distributed MIMO encoding process in this embodiment starts by receiving several input signals in step 1102.
  • a channel encoding unit, a symbol mapping unit, a spatial multiplexing unit, and the like generate a spatial data stream intended to be broadcast / multicast from the received input signal (input bit sequence) to the user terminal.
  • This processing may include channel coding and modulation and / or other techniques known to those skilled in the art.
  • MIMO coding is applied by multiplying the quantization matrix.
  • the MIMO-encoded spatial data stream is transmitted from a plurality of antennas and broadcast / multicast from each base station of the SFN.
  • FIG. 12 to FIG. 14 are diagrams showing simulation results regarding the gain of the system capacity obtained by distributed MIMO encoding when MBMS is performed in the SFN.
  • the ergodic capacity was calculated for each different spatial correlation value by the above formulas (6) and (7), and a comparison was made between pure spatial multiplexing and spatial multiplexing using distributed MIMO coding. .
  • FIG. 12 shows a conventional implementation using pure spatial multiplexing and distributed MIMO coding corresponding to the first embodiment shown in FIGS. 3 and 4 using two transmitting antennas and two receiving antennas.
  • the comparison result between form spatial multiplexing is shown.
  • the spatial multiplexing of the present embodiment using distributed MIMO coding increases the system capacity, and a considerable gain can be obtained particularly in a channel having a high spatial correlation.
  • the gain of the system capacity is about 1 to 1.5 dB
  • the spatial correlation value between the two transmission antennas is 0.9
  • the gain of the system capacity is about 2.5 to 3.5 dB.
  • FIG. 13 shows a conventional implementation using pure spatial multiplexing and distributed MIMO coding corresponding to the second embodiment shown in FIGS. 5 and 6 using four transmitting antennas and two receiving antennas.
  • pure spatial multiplexing transmits data stream S 1 from both the first and third antennas at each base station, and data stream S 2 at both the second and fourth antennas at each base station. Means to send from.
  • the spatial multiplexing of the present embodiment using distributed MIMO coding increases the system capacity, and a considerable gain can be obtained particularly in a channel having a high spatial correlation.
  • the gain of the system capacity is about 2 dB, and the four transmission antennas are obtained.
  • the gain of the system capacity is about 2.5 dB.
  • FIG. 14 shows a conventional implementation using pure spatial multiplexing and distributed MIMO coding corresponding to the third embodiment shown in FIGS. 7 and 8 using four transmitting antennas and four receiving antennas.
  • the comparison result between form spatial multiplexing is shown.
  • the spatial multiplexing of the present embodiment using distributed MIMO coding increases the system capacity, and a considerable gain can be obtained particularly in a channel having a high spatial correlation.
  • the spatial correlation values between two of the four transmitting antennas are 0.6, 0.4, and 0.2, respectively, a system capacity gain of about 1 to 1.2 dB is obtained.
  • the spatial correlation value between two of the two transmitting antennas is 0.9, 0.6, and 0.3, a gain of the system capacity is obtained from about 2.5 to 5 dB.
  • a plurality of base stations are applied by applying distributed MIMO encoding using different encoding matrices in a plurality of base stations.
  • Multiplexing diversity can be realized in the base station domain between stations. Therefore, even when the spatial correlation between the transmitting antennas is high, the loss of system capacity can be reduced, so that the frequency utilization efficiency in SFN can be increased and the communication performance can be improved.
  • each functional block used in the description of each of the above embodiments is typically realized as an LSI that is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them.
  • the name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.
  • the method of circuit integration is not limited to LSI, and implementation with a dedicated circuit or a general-purpose processor is also possible.
  • An FPGA Field Programmable Gate Array
  • a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.
  • the present invention has an effect that it is possible to reduce a loss of system capacity and improve communication performance even when there is a spatial correlation between transmitting antennas in a wireless communication system to which spatial multiplexing is applied. It is useful as a wireless communication apparatus such as a cellular communication system using a MIMO system for performing communication using a plurality of antennas, a wireless communication system, a wireless communication method, and the like.

Abstract

Selon l'invention, les performances de communication sont améliorées par réduction des pertes d'une capacité de système, même lorsqu'il existe une corrélation spatiale entre des antennes d'émission dans un système de communication sans fil auquel un multiplexage spatial est appliqué. Une première station de base (201) et une seconde station de base (205) amènent respectivement des parties de codage MIMO (202, 206) à effectuer un codage MIMO de flux S1 et S2 obtenus par multiplexage spatial d'informations identiques, en utilisant des matrices de codage mutuellement différentes. Ensuite, la première station de base (201) transmet des données codées MIMO à partir d'antennes d'émission (204A, 204B) à un terminal utilisateur, et une seconde station de base (205) transmet des données codées MIMO à partir d'antennes d'émission (208A, 208B) au terminal utilisateur.
PCT/JP2009/001184 2008-03-26 2009-03-17 Dispositif de communication sans fil, système de communication sans fil et procédé de communication sans fil WO2009119041A1 (fr)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021165516A1 (fr) 2020-02-19 2021-08-26 Anabio Technologies Limited Microcapsules enrobées et procédés pour leur de production

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006138203A1 (fr) * 2005-06-14 2006-12-28 Qualcomm Incorporated Diversite spatiale de transmission pour des reseaux cellulaires a frequence unique
WO2008013034A1 (fr) * 2006-07-25 2008-01-31 Sharp Kabushiki Kaisha Système de communication mobile, dispositif de station de base et dispositif de station mobile

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2006138203A1 (fr) * 2005-06-14 2006-12-28 Qualcomm Incorporated Diversite spatiale de transmission pour des reseaux cellulaires a frequence unique
WO2008013034A1 (fr) * 2006-07-25 2008-01-31 Sharp Kabushiki Kaisha Système de communication mobile, dispositif de station de base et dispositif de station mobile

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021165516A1 (fr) 2020-02-19 2021-08-26 Anabio Technologies Limited Microcapsules enrobées et procédés pour leur de production

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