WO2003103201A1 - Procede et appareil permettant de recevoir un signal d'un systeme a acces multiple par code de repartition a plusieurs entrees/plusieurs sorties (amcr mimo) - Google Patents

Procede et appareil permettant de recevoir un signal d'un systeme a acces multiple par code de repartition a plusieurs entrees/plusieurs sorties (amcr mimo) Download PDF

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Publication number
WO2003103201A1
WO2003103201A1 PCT/CN2002/000377 CN0200377W WO03103201A1 WO 2003103201 A1 WO2003103201 A1 WO 2003103201A1 CN 0200377 W CN0200377 W CN 0200377W WO 03103201 A1 WO03103201 A1 WO 03103201A1
Authority
WO
WIPO (PCT)
Prior art keywords
receiving
transmitting
antenna
antennas
channel
Prior art date
Application number
PCT/CN2002/000377
Other languages
English (en)
Chinese (zh)
Inventor
Gang Wang
Dandan Wang
Shaojun Xu
Original Assignee
Linkair Communications,Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Linkair Communications,Inc. filed Critical Linkair Communications,Inc.
Priority to AU2002315715A priority Critical patent/AU2002315715A1/en
Priority to PCT/CN2002/000377 priority patent/WO2003103201A1/fr
Priority to CN02819172.2A priority patent/CN1561593A/zh
Publication of WO2003103201A1 publication Critical patent/WO2003103201A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7097—Interference-related aspects
    • H04B1/7103—Interference-related aspects the interference being multiple access interference
    • H04B1/7105—Joint detection techniques, e.g. linear detectors
    • H04B1/71057—Joint detection techniques, e.g. linear detectors using maximum-likelihood sequence estimation [MLSE]
    • 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
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • 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
    • H04L25/03—Shaping networks in transmitter or receiver, e.g. adaptive shaping networks
    • H04L25/03006—Arrangements for removing intersymbol interference
    • H04L25/03178—Arrangements involving sequence estimation techniques
    • H04L25/03248—Arrangements for operating in conjunction with other apparatus
    • H04L25/03292—Arrangements for operating in conjunction with other apparatus with channel estimation circuitry

Definitions

  • the present invention belongs to the field of communication technology, and specifically it is a receiving method and device based on MIMO CDMA.
  • TDMA time division multiple access
  • CDMA code division multiple access
  • the main disadvantages of the TDMA method are: The system capacity is still not ideal; like the frequency division multiple access (FDMA) method, the handover performance of the TDMA method is still incomplete.
  • FDMA frequency division multiple access
  • North America has launched the IS-95 / CDMA digital mobile communication system.
  • the IS-95 / CDMA system shows great potential for development due to its simple frequency planning, large system capacity, high frequency reuse factor, strong multipath resistance, good communication capacity, and soft capacity.
  • a wave of research into CDMA technology was set off within the scope.
  • the two main candidates for the third-generation digital cellular mobile communication system are the CDMA2000 system in North America and the WCDMA system in Europe. Both are systems based on CDMA technology. It can be seen that CDMA has been widely accepted as a third-generation mobile communication system Important technology.
  • CDMA code divi s ion mul t iple access
  • code division multiple access is assigned to each user with a unique coding sequence (spreading code), which is used to spread code the bearer signal.
  • the frequency term is broadened;
  • the correlation of the pseudo code is used for despreading processing, and the useful-signal frequency term is restored to a narrow-band spectrum.
  • Broadband unwanted signals are not compatible with local pseudocode Off, so it cannot be despread, and it is still a wide-band spectrum; narrow-band unwanted signals are expanded into a wide-band spectrum by local pseudo-code. Since the unwanted interference signal is a wideband spectrum and the useful signal is a narrowband spectrum, we can use a narrowband filter to eliminate out-of-band interference levels, so the signal-to-noise ratio in the narrowband is greatly improved.
  • MIMO Multiple Input Mult iple Output
  • a significant feature of mobile channels is their multipath delay.
  • the traditional CDMA uses a RAKE receiver to take advantage of the characteristics of multipath and diversity reception, which greatly improves the gain.
  • MIM0 was introduced into CDMA, the form of the signal at the receiving end also changed due to the change of channel conditions, so how to deal with multipath becomes a problem that needs to be solved urgently at the receiving end.
  • An object of the present invention is to provide a MIMO CDMA-based receiving method and device, which are used to solve the problem of performance degradation of a MIMO CDMA system caused by the receiving method, that is, how to receive signals in a multipath system environment .
  • the performance of the present invention can keep good performance whether in a low-speed environment or in a high-speed environment, whether for a single user or multiple users.
  • the technical solution of the present invention is: A receiving method based on MIMO CDMA, characterized in that the transmitting end: uses at least two transmitting antennas to transmit signals; the receiving end: at least one receiving antenna receives signals transmitted by the transmitting antennas, and Channel estimation to obtain channel parameters, use The channel parameters and the steps of the maximum likelihood principle yield an output signal.
  • the transmitting terminal adopts at least two transmitting antennas to transmit signals means: the transmitting terminal may use two or more transmitting antennas to transmit signals; the receiving terminal uses at least one receiving antenna to receive signals transmitted by the transmitting antennas It means: The receiving end can use one or more receiving antennas to receive the signals transmitted by the transmitting antennas.
  • the transmitting terminal uses at least two transmitting antennas to transmit signals means that: the transmitting terminal can use two transmitting antennas to transmit signals; the receiving terminal uses at least one receiving antenna to receive signals transmitted by the transmitting antennas means: receiving The end can use two receiving antennas to receive the signal transmitted by the transmitting antenna.
  • the receiving step of the receiving end includes:
  • the receiving end uses at least one receiving antenna to receive signals transmitted by the transmitting antenna;
  • the receiving step of the receiving end may further include:
  • the receiving end uses the receiving antenna 1 and the receiving antenna 2 to receive signals transmitted by the transmitting antenna 1 and the transmitting antenna 2;
  • ⁇ represent the time-domain response vector of the channel between the transmitting antenna 1 and the receiving antenna 1.
  • the response characteristics of the channel remain unchanged within one symbol;
  • the minimum Euclidean distance principle is used for joint demodulation to obtain the output signal.
  • the described MIMO CDMA-based receiving method is applicable to a single carrier. At this time, the receiving end needs to perform de-carrier processing on the received signal.
  • the described MIMO CDMA-based receiving method is applicable to multiple carriers, and the receiving end needs to perform de-carrier processing on the received signal.
  • the receiving method based on MIMO CDMA can be extended to the receiving method of more than two transmitting antennas and one receiving antenna.
  • the described MIMO CDMA-based receiving method can be extended to a receiving method of more than two transmitting antennas and more than two receiving antennas.
  • the present invention also provides a receiving device based on MIMO CDMA, which includes:
  • Transmitting device transmitting antenna; receiving antenna, receiving device;
  • the receiving device is: a receiving device that obtains a channel parameter through channel estimation and processes the maximum likelihood principle to obtain a receiving structure;
  • the output signal of the transmitting device is the input of the transmitting antenna, and the output signal of the transmitting antenna is used as the input of the receiving antenna after channel attenuation.
  • the output signal of the receiving antenna is the input of the receiving device, and the receiving device outputs the restored signal.
  • the transmitting antenna includes: two or more transmitting antennas; and the receiving antenna includes: one or more receiving antennas.
  • the transmitting antenna includes: two transmitting antennas; the receiving antenna includes: two receiving antennas.
  • the receiving device includes: a channel estimation device capable of obtaining channel parameters; a despreading device capable of despreading a received signal; a joint demodulation device using a maximum likelihood principle and a minimum Euclidean distance principle.
  • the receiving device based on MIMO CDMA further includes a carrier removing device.
  • the effect of the present invention is to solve the problem of performance degradation of the MB10 CDMA system caused by the receiving method.
  • the performance of the present invention can be maintained no matter in a low-speed environment or a high-speed environment, whether for a single user or multiple users.
  • the present invention applies the maximum likelihood principle (ML: Maximum Likel ihood) to an M 10 CDMA system, which effectively solves the How to receive signals in a multipath mobile environment. Its appearance makes it possible for MIM0 to be used for CDMA. It greatly increases the system capacity and can transmit higher speed data.
  • two antennas use the same spreading code, they can be used to transmit high-speed data to one user; when different spreading codes are used, they can be used to carry different users.
  • the number of carriers can be flexibly arranged according to the bandwidth, and the change of the receiver is not large. This is also applicable to future multi-carrier CDMA systems.
  • FIG. 1 is a schematic diagram of a channel with two transmissions and two receptions
  • Figure 2 is a simplified diagram of a dual launch system
  • FIG. 3 is a schematic diagram of receiving
  • Figure 4 shows the simulation curves of 1-path, 2-path, and two-carrier of an ML receiver, where BER: bit error rate, SNR: signal-to-noise ratio;
  • Figure 5 shows the performance (three-carrier) simulation curves at different vehicle speeds
  • Figure 6 is a comparison simulation curve using the results of traditional MRC (Maximum Ratio Combining) and the ML method of this patent.
  • channel parameters of a multipath channel are obtained by estimating channel parameters.
  • the receiver obtained by the maximum likelihood principle is used to demodulate the final symbol with this parameter.
  • the method and device of the present invention are described below by taking a system of two transmissions and two receptions as an example.
  • ⁇ represents a channel time domain response vector between the transmitting antenna 1 and the receiving antenna 1.
  • the channel is a two-path Rayleigh fading channel. It is assumed that the response characteristics of the channel remain unchanged within one symbol, which is easily satisfied in slow fading channels.
  • a 12 represents the second path, and so on.
  • CDMA Code Division Multiple Access
  • SISO single-input single-output
  • C (t-Tc) is the received signal on receive antenna 1 and receive antenna 2.
  • t ⁇ b ⁇ C + bAC so that the signal received on the receiving antenna 1 contains not only b p but also b 2 .
  • b p 13 2 is useful information. Therefore, the traditional CDMA receiver treats all other symbols as interference. This can cause performance degradation. Even if b p b 2 information is received, how to separate b 15 b 2 from it? The present invention solves this problem.
  • the following uses the ML (maximum likelihood) criterion to derive the structure diagram of this receiver.
  • the ML guideline is to make
  • T s is the time length of one symbol.
  • R is an identity matrix.
  • R is an identity matrix.
  • R is an identity matrix.
  • (2) can be reduced to So the minimum of (2) is to find the minimum of (3).
  • the receiver structure designed according to (3) is shown in Fig. 3: where the channel estimation is to estimate the channels H ', H ", and the signals received by the two antennas are despread to input the above conditions into the demodulator.
  • the modulator uses the principle of minimum Euclidean distance to perform joint demodulation to obtain the best output.
  • This receiving method is applicable not only to a single carrier, but also to a multi-carrier system. Just add the de-carrier equipment before the de-spreading of the receiver in Figure 3.
  • Figure 4 shows the simulation performance when using two carriers
  • Figure 5 shows the performance when using three carriers.
  • the soft decoding means that a Viterbi decoder is used to directly complete the decision from the received signal to bit. It can be seen that its reception performance is also good under multipath conditions.
  • Figure 5 also illustrates that this receiving method is perfectly suitable for high-speed moving conditions. As long as the performance of the spreading codeword is good enough for multiple users, the impact is not great.
  • Figure 6 is a comparison of the results using conventional MRC (Maximum Ratio Combining) and the ML method of this patent. The performance improvement is obvious.
  • the complexity of this optimal receiving method is related to the size of the constellation and the number of transmitting and receiving antennas. In the case of a single user, 16QAM modulation, and two transmissions and two receptions, the complexity is 16 2. In general, for a single user, if M modulation is used, there are n signals jointly demodulated (that is, there are n transmissions and receptions). Antenna), if k carriers are used on each antenna, the complexity is directly proportional. Considering that it is impossible for a mobile terminal to have too many antennas, it is appropriate to take n as 1.
  • the invention applies the ML principle to the MIM0 + CDMA system. This effectively solves the problem of how to receive signals in multipath and multicarrier. Its appearance makes it possible for MIM0 to be used in CDMA. It is suitable for both increasing system capacity and transmitting higher-speed data. When two antennas use the same spreading code, it can be used to transmit high-speed data to a user. When different spreading codes are used, they can be used to carry different users. The number of carriers can be flexibly arranged according to the bandwidth, while the receiver changes little. This will certainly be used in future multi-carrier CDMA systems.

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

Abstract

Cette invention a trait à un procédé ainsi qu'à un appareil permettant de recevoir un signal dans un système (AMCR MIMO), se caractérisant par le fait, qu'au moins deux antennes émettent, du côté émission, un signal, qu'au moins une antenne, du côté réception, reçoit le signal, que l'on obtient des paramètres de canal par estimation de canal et que l'on utilise ces paramètres de canal et le principe de la vraisemblance maximale (ML) pour un gain de signal en sortie. On applique, dans le cadre de ce procédé, le principe de ML dans un système AMCR MIMO, ce qui permet de résoudre les problèmes de réception de signal dans un environnement mobile multiple. L'application de ce principe rend possible l'utilisation de plusieurs entrées/plusieurs sorties MIMO dans un système AMCR. Cette application permet, non seulement d'augmenter la capacité du système, mais également d'émettre à un débit plus élevé. Le nombre des porteuses utilisables dépend de la vitesse de la largeur de bande, sans grande modification du récepteur. Il sera également possible de l'utiliser dans un système AMCR à plusieurs porteuses.
PCT/CN2002/000377 2002-05-31 2002-05-31 Procede et appareil permettant de recevoir un signal d'un systeme a acces multiple par code de repartition a plusieurs entrees/plusieurs sorties (amcr mimo) WO2003103201A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AU2002315715A AU2002315715A1 (en) 2002-05-31 2002-05-31 Method and apparatus for receiving signal based on mimo cdma
PCT/CN2002/000377 WO2003103201A1 (fr) 2002-05-31 2002-05-31 Procede et appareil permettant de recevoir un signal d'un systeme a acces multiple par code de repartition a plusieurs entrees/plusieurs sorties (amcr mimo)
CN02819172.2A CN1561593A (zh) 2002-05-31 2002-05-31 一种基于mimocdma的接收方法及装置

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2002/000377 WO2003103201A1 (fr) 2002-05-31 2002-05-31 Procede et appareil permettant de recevoir un signal d'un systeme a acces multiple par code de repartition a plusieurs entrees/plusieurs sorties (amcr mimo)

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Publication Number Publication Date
WO2003103201A1 true WO2003103201A1 (fr) 2003-12-11

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CN (1) CN1561593A (fr)
AU (1) AU2002315715A1 (fr)
WO (1) WO2003103201A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100463455C (zh) * 2005-03-07 2009-02-18 西安交通大学 多输入多输出系统信道容量的估计方法
CN101056152B (zh) * 2006-04-30 2010-08-04 华为技术有限公司 通用移动通信系统中的传输方法及其系统

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1215949A (zh) * 1997-10-23 1999-05-05 富士通株式会社 码分多址接收设备
CN1304218A (zh) * 2000-01-13 2001-07-18 朗迅科技公司 多输入多输出无线系统的时空处理
CN1325198A (zh) * 2000-05-22 2001-12-05 美国电报电话公司 多输入多输出正交频分多路复用系统

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1215949A (zh) * 1997-10-23 1999-05-05 富士通株式会社 码分多址接收设备
CN1304218A (zh) * 2000-01-13 2001-07-18 朗迅科技公司 多输入多输出无线系统的时空处理
CN1325198A (zh) * 2000-05-22 2001-12-05 美国电报电话公司 多输入多输出正交频分多路复用系统

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AU2002315715A1 (en) 2003-12-19
CN1561593A (zh) 2005-01-05

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