Time-frequency coding diversity MT-CDMA (multiple tone-code division multiple access) system transmitting and receiving method

Abstract

The invention relates to a time-frequency coding diversity MT-CDMA (multiple tone-code division multiple access) system transmitting and receiving method and belongs to a broadband multicarrier wireless communication transmitting and receiving method. A two-dimensional dispreading and multi-path separation module utilizes a time-frequency two-dimensional spread spectrum code group matrix, the two-dimensional dispreading and multi-path separation of users is realized, multiple paths of mutually irrelevant fading signals are obtained, each path of signals is merged by a phase correction and merging technology, and final output results are obtained through judgment; the spread spectrum code length can be any integral multiple of the subcarrier number, each user carries out two-dimensional coding according to a time-frequency coding grid chart, the duration time of a basic frame is enabled to be constant, and the data rate of a single user of a system is not reduced; and multiple multicarrier symbols are used as the basic frame during the system processing, and the basic frame is respectively used as a basic unit of processing time at transmitter and receiver ends. The transmitting and receiving method has the advantages that the method maintains the compatibility of the existing MT-CDMA system on the basis of a time-frequency coding diversity MT-CDMA wireless communication system of a RAKE receiver, and the system modification can be conveniently completed.

Description

technical field [0001] The invention relates to a method for transmitting and receiving broadband multi-carrier wireless communication, in particular to a method for transmitting and receiving time-frequency code diversity MT-CDMA system. Background technique [0002] The indisputable competitiveness of CDMA technology has been successfully applied to the second and third generation mobile communication systems. However, the capacity of CDMA is limited by multiple access interference and multipath interference, while multi-carrier technology is not effective for multipath interference and intersymbol interference. Crosstalk has a strong resistance, so multi-carrier CDMA becomes the most promising system scheme for future broadband mobile communication systems. Since 1993, there have been articles discussing the combination of multi-carrier modulation and spread spectrum technology, which are mainly divided into two categories: MC-CDMA with frequency diversity (anti-multipath...

AI Technical Summary

Problems solved by technology

[0002] The indisputable competitiveness of CDMA technology has been successfully applied to the second and third generation mobile communication systems. However, the capacity of CDMA is limited by multiple access interference and multipath interference, while multi-carrier technology is not effective for multipath interference and intersymbol interference. Crosstalk has strong resistance, so multi-carrier CDMA becomes the most promising system solution for future broadband mobile communication systems

Since 1993, there have been articles discussing the combination of multi-carrier modulation and spread spectrum technology, which are mainly divided into two categories: MC-CDMA with frequency diversity (anti-multipath fading) and MC-CDMA with time diversity (anti-time selective fading). DS-CDMA, while radio wave propagation must resist both multipath fading and time-selective fading, so a two-dimensional spread-based OFDM-CDMA system emerges as the times require, which can effectively utilize time diversity and frequency diversity at the same time The effect of the receiver improves the performance of the receiver to a certain extent, but this two-dimensional spread spectrum method increases the length of the spread spectrum code to increase the user capacity, and at the same time, the cost is a decrease in the transmission rate of a single user, which is obviously not suitable for Today, the demand for communication is getting higher and higher

Images