CN102340328B - Signal transmitting and receiving method of multi-carrier MIMO (multiple input multiple output) system based on chip-level spread spectrum code of space-time-frequency three-dimensional complementary code - Google Patents

Abstract

The invention discloses a signal transmission and reception method of a multi-carrier MIMO (multiple input multiple output) system based on a chip-level spread spectrum code of a space-time-frequency three-dimensional complementary code, relating to an MIMO system based on a chip-level spread spectrum code of a space-time-frequency three-dimensional complementary code. Through the invention, the problem of poor multi-path interference resistance of the MIMO system adopting the existing coding mode is solved; and the existing coding mode is only applicable to the condition that the channel response is in slow fading, namely that the channel response is kept unchanged for sure within the time of the symbol bits. A transmitting end of the multi-carrier MIMO system performs spectrum spread by using the chip-level spread spectrum code of the space-time-frequency three-dimensional complementary code; and a receiving end performs de-spreading operation by using the chip-level spread spectrum code of the space-time-frequency three-dimensional complementary code. The multi-path interference resistance of the MIMO system disclosed by the invention is greatly improved, and the MIMO system is suitable for wireless communication processes.

Description

Signal based on the multi-carrier MIMO system of the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number transmits and receives method

Technical field

The signal that the present invention relates to a kind of mimo system of the chip-level spread spectrum coding based on Space-Time-frequency three-dimensional complementary sign indicating number transmits and receives method.

Background technology

(Orthogonal Frequency Division Multiplexing OFDM) is a kind of high speed transmission technology that proposes at the high spectrum utilization ratio to be called as the OFDM of " the 4th third-generation mobile communication technology ".The OFDM technology has very many good characteristics, such as the high availability of frequency spectrum, extendible bandwidth, frequency spectrum resource distribution flexibly, anti-multipath decline etc.Yet; the OFDM technology still exist a lot of shortcomings as, power peak relatively more responsive to frequency deviation and phase noise and average than big etc.; especially the intersymbol interference in order to realize being produced by multipath, OFDM introduced as at interval Cyclic Prefix of intersymbol protection (Cyclic Prefix, CP).The introducing of CP reduces the decay of OFDM really greatly, but has taken the most valuable resource, has influenced the utilization ratio of frequency spectrum on the contrary.Therefore the expectation exploitation is a kind of can satisfy the new technology of the many demands of next generation wireless communication, and it can not introduce unnecessary resource consumption under the prerequisite that ensures the anti-multipath decline.

Numerous advantages such as the low detection property of, signal anti-interference owing to having, confidentiality, low flux density, code division multiple access (CDMA, Code Division Multiple Access) technology has been widely used in the second generation and 3-G (Generation Three mobile communication system).CDMA technology is the application of spread spectrum technic in multi-user comm.In cdma system, each user has distributed different orthogonal intersections, utilizes the orthogonality of frequency expansion sequence, can make all users share identical frequency spectrum in all time.Present modal spreading code is nothing more than being M-sequence, Gold code and Walsh code and OVSF code etc., but the orthogonality of these spreading codes is not very perfect, this just makes cdma system be subjected to multiple access and disturbs (MAI, Multiple Access Interference) and multipath disturb the influence of (MI, Multi-path Interference).Especially under high message transmission rate, multipath will cause disturbing between serious chip, and be difficult to so at a high speed spreading code is carried out synchronously.Therefore, we need develop new spreading code and solve the problem that traditional C DMA system exists, and make CDMA technology develop towards the direction of the required two-forty of next generation wireless communication system, high spectrum utilization.

Space-time code is the coded system that present mimo system is commonly used to the implementation space diversity, its coded system has many kinds, common STBC (space-time block code), STTC (space-time trellis code) and the STDC (space-time differential code) etc. of mainly containing.But the shortcoming Shi No of Space Time Coding maximum has the problem of considering that multipath disturbs.Though some paper has the orthogonality of considering between the multi-user multi-antenna, but the just orthogonality of symbol level (symbol-level) that they discuss, it can only be used for channel response is the situation of slow fading, use several symbol bits to do Space Time Coding, channel response just must remain unchanged in the time of these several symbol bits, otherwise error rate can greatly rise, and this has obviously run counter to the demand of next generation wireless communication.And when decoding, whole bits that must harvest for Space Time Coding can solve signal, namely can't reach instantaneous decoding.

Summary of the invention

The present invention is for the problem of the anti-multipath jamming performance difference that solves the mimo system that adopts existing coded system, thereby provides a kind of signal of multi-carrier MIMO system of the chip-level spread spectrum coding based on Space-Time-frequency three-dimensional complementary sign indicating number to transmit and receive method.

Signal based on the multi-carrier MIMO system of the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number transmits and receives method, and for each the user k among K the user, its signal emission process is:

Step 1, data to be sent are carried out serial/parallel conversion, obtain parallel N circuit-switched data;

Step 2, the described parallel N circuit-switched data of step 1 adopted the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number respectively

Carry out spread spectrum, the data behind the spread spectrum of acquisition N road;

Step 3, employing M way carrier wave are modulated the every circuit-switched data in the data behind the N road spread spectrum of step 2 acquisition respectively, obtain one road modulation signal; Obtain N road modulation signal in the N circuit-switched data altogether, described N road modulation signal is sent to wireless channel by the N transmit antennas; The described M way carrier wave frequency of correspondence respectively is f ₁, f ₂..., f _M

For each the user k among K the user, its signal receiving course is:

Step 4, receiving terminal receive the N road modulation signal of transmitting terminal emission by N root reception antenna; Adopt M way carrier wave respectively the every road modulation signal in the modulation signal of described N road to be carried out demodulation, obtain one road demodulating data, N road modulation signal obtains the data after the demodulation of N road altogether; The described M way carrier wave frequency of correspondence respectively is f ₁, f ₂..., f _M

Step 5, the every circuit-switched data in the data after the N road demodulation that obtains in the step 4 all adopted the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number

Carry out despreading, the data after the acquisition N road despreading;

Step 6, with the data after the N road despreading of the acquisition in step 5 summations, and judgement back output;

K, N, M are positive integer, N _TBe number of transmit antennas.

The chip-level spread spectrum coding of Space-Time in step 2 and the step 5-frequency three-dimensional complementary sign indicating number

Production method be:

Steps A, three M * M orthogonal dimension matrix A of employing, B, and D, dimension M are the number of users that subcarrier number and system can support; The B matrix is used for distinguishing the user, and the D matrix is used for distinguishing carrier wave; Finish when distinguishing the user, finish the coding in frequency dimension;

Step B, adopt a N again _T* N _TThe orthogonal dimension matrix F is given different antennas with each row vector of matrix F, finishes the coding in spatial domain, N _TIt is number of transmit antennas;

Step C, to matrix A, B, the row and column vector of D and F is arranged, and with matrix A, B, multiplying each other in the corresponding position among D and the F in each row matrix vector, obtains the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number.

The present invention adopts the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number as the spreading code of user data, and the anti-multipath jamming performance of mimo system significantly improves.

Description of drawings

Fig. 1 is the signal emission schematic flow sheet that the signal of the multi-carrier MIMO system of the chip-level spread spectrum coding based on Space-Time-frequency three-dimensional complementary sign indicating number of the present invention transmits and receives method; Fig. 2 is that the signal that the signal of the multi-carrier MIMO system of the chip-level spread spectrum coding based on Space-Time-frequency three-dimensional complementary sign indicating number of the present invention transmits and receives method receives schematic flow sheet; Fig. 3 is embodiment one described matrix A, B, and the row and column vector of D and F carries out the arrangement mode schematic diagram; Fig. 4 is the schematic diagram of the used code word of two users and two antennas; Wherein User=1 is first user, N _TFirst antenna of=1 first user; User=1 is first user, N _TSecond antenna of=2 first users; User=2 is second user, N _TFirst antenna of=1 second user; User=2 is second user, N _TSecond antenna of=2 second users.

Embodiment

Embodiment one, in conjunction with Fig. 1 this embodiment is described, signal based on the multi-carrier MIMO system of the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number transmits and receives method, for each the user k among K the user, its signal emission process is:

Step 1, data are carried out serial/parallel conversion, obtain parallel N circuit-switched data;

Step 2, the described parallel N circuit-switched data of step 1 adopted the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number respectively Carry out spread spectrum, the data behind the spread spectrum of acquisition N road;

Every circuit-switched data in the data behind step 3, the N road spread spectrum that step 2 is obtained is respectively at f ₁, f ₂..., f _MFrequency under modulate with M way carrier wave, obtain one road modulation signal; Obtain N road modulation signal in the N circuit-switched data altogether, described N road modulation signal is sent to wireless channel by the N transmit antennas;

For each the user k among K the user, its signal receiving course is:

Step 4, receiving terminal receive the N road modulation signal of transmitting terminal emission by N root reception antenna; And with the every road modulation signal in the modulation signal of described N road respectively at f ₁, f ₂..., f _MFrequency under carry out demodulation, obtain the data after the demodulation, N road modulation signal obtains the data after the demodulation of N road altogether;

Step 5, the every circuit-switched data in the data after the N road demodulation that obtains in the step 4 all adopted the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number Carry out despreading, the data after the acquisition N road despreading;

Step 6, with the data after the N road despreading of the acquisition in step 5 summations, and judgement back output;

K, N, M are positive integer.

The chip-level spread spectrum coding of Space-Time in step 2 and the step 5-frequency three-dimensional complementary sign indicating number

Production method be:

Produce three identical or different M * M dimension matrix orthogonal matrix A, B, and D.Dimension M has determined the number of users that subcarrier number and system can support.The B matrix is used for distinguishing the user, and the D matrix is used for distinguishing carrier wave, and namely each row vector of B matrix is given different users, and each row vector of D matrix is given different carrier waves.Finish when distinguishing the user, at the coding of frequency dimension.

Produce a N again _T* N _TThe orthogonal dimension matrix F, N _TIt is number of transmit antennas.Each row vector of matrix F is given different antennas, finishes the coding in spatial domain.

By matrix A, B, the row and column vector of D and F after arranging according to mode shown in Figure 3, can access the producing method of 3 dimension MIMO chip-level spread spectrum codings.Wherein

Be the row vector of F matrix,

N for matrix _TThe 1st element of row; B _kBe the row vector of B matrix, b _K1Capable the 1st element of k for matrix; A _MBe the row vector of A matrix, D _MBe D matrix itself; Obtain the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number after corresponding position in each row matrix vector in above-mentioned multiplied each other.

Below say the chip-level spread spectrum coding method of the Space-Time-frequency three-dimensional complementary sign indicating number among the present invention by specific embodiment: hypothesis matrix $A=\left[\begin{array}{cc}1& 1\\ 1& -1\end{array}\right],$ $B=\left[\begin{array}{cc}1& 1\\ 1& -1\end{array}\right],$ $D=\left[\begin{array}{cc}1& 1\\ 1& -1\end{array}\right]$ With $F=\left[\begin{array}{cc}1& 1\\ 1& -1\end{array}\right],$ This moment M=2, N _T=2.In addition, this only is an example of 2 * 2 orthogonal matrixes, can also choose other orthogonal matrix.Process has been chosen identical orthogonal matrix for the purpose of simplifying the description, that is to say and can choose 2 * 2 orthogonal matrix wantonly.Because M=2, so the number of users that code character can be supported is 2, code length is N=M ²N _TThe used code word of two users and two antennas as shown in Figure 4.Be the chip-level coding of the typical empty time-frequency three-dimensional complementary sign indicating number of part below, below use N_T instead and represent antenna number:

The present invention proposes a kind of use based on the chip-level coding method of empty time-frequency three-dimensional complementary sign indicating number, the two-dimensional spread-spectrum coding is developed into the new technology of employing Space Time-three-dimensional spread spectrum coding of frequency.The chip-level of empty time-frequency three-dimensional complementary sign indicating number is encoded and is applied in the MIMO cdma system of multicarrier as spreading code, has guaranteed the availability of frequency spectrum and multi-user's number.The spreading code of the present invention design in addition, be applied in a brand-new CDMA-MIMO physical layer system framework, do not use the OFDM technology, avoided that the frequency deviation of OFDM and phase noise are relatively responsive, power peak and average be than big shortcoming, avoided the CP in the ofdm system simultaneously, saved resource and can improve the availability of frequency spectrum.

Claims (2)

1. the signal based on the multi-carrier MIMO system of the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number transmits and receives method, and it is characterized in that: for each the user k among K the user, its signal emission process is:

Step 1, data to be sent are carried out serial/parallel conversion, obtain parallel N circuit-switched data;

Step 2, the described parallel N circuit-switched data of step 1 adopted the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number respectively

Carry out spread spectrum, the data behind the spread spectrum of acquisition N road;

Step 3, employing M way carrier wave are modulated the every circuit-switched data in the data behind the N road spread spectrum of step 2 acquisition respectively, obtain one road modulation signal; Obtain N road modulation signal in the N circuit-switched data altogether, described N road modulation signal is sent to wireless channel by the N transmit antennas; The described M way carrier wave frequency of correspondence respectively is f ₁, f ₂..., f _M

For each the user k among K the user, its signal receiving course is:

Step 4, receiving terminal receive the N road modulation signal of transmitting terminal emission by N root reception antenna; Adopt M way carrier wave respectively the every road modulation signal in the modulation signal of described N road to be carried out demodulation, obtain one road demodulating data, N road modulation signal obtains the data after the demodulation of N road altogether; The described M way carrier wave frequency of correspondence respectively is f ₁, f ₂..., f _M

Step 5, the every circuit-switched data in the data after the N road demodulation that obtains in the step 4 all adopted the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number

Carry out despreading, the data after the acquisition N road despreading;

Step 6, with the data after the N road despreading of the acquisition in step 5 summations, and judgement back output;

K, N, M are positive integer, N _TBe number of transmit antennas.

2. the signal of the multi-carrier MIMO system of the chip-level spread spectrum coding based on Space-Time-frequency three-dimensional complementary sign indicating number according to claim 1 transmits and receives method, it is characterized in that: the chip-level spread spectrum coding of Space-Time in step 2 and the step 5-frequency three-dimensional complementary sign indicating number

Production method be:

Steps A, three M * M orthogonal dimension matrix A of employing, B, and D, dimension M are the number of users that subcarrier number and system can support; The B matrix is used for distinguishing the user, and the D matrix is used for distinguishing carrier wave; Finish when distinguishing the user, finish the coding in frequency dimension;

Step B, adopt a N again _T* N _TThe orthogonal dimension matrix F is given different antennas with each row vector of matrix F, finishes the coding in spatial domain, N _TIt is number of transmit antennas;

Step C, to matrix A, B, the row and column vector of D and F is arranged, and with matrix A, B, multiplying each other in the corresponding position among D and the F in each row matrix vector, obtains the chip-level spread spectrum coding of Space-Time-frequency three-dimensional complementary sign indicating number.

Images