The Research On Transmit Diversity Scheme And Its Coding Arithmetic In Mobile Communication

With the rapid development of the global mobile communication, the demand ofpeople for the mobile communication business is increasing.And the requirement forcommunication quality is higher and higher. How to repel all kinds of losses andfadings in the airhas been receiveing a great deal of attention, and how toimprove thecommunication qualityhas becomed a very important thing. The paperresearchesandanalysesthequestionsabove precisely.In this paper, the mobile communication development status, the major problemsof mobile communication and their solutions are firstly studied, the concepts ofdiversity scheme and transmit diversity scheme are educed. More attention is paid tothetransmit diversity scheme and basic principle of multi-carriers OFDM technology.Including the base of transmit diversity scheme-- rationale of MIMO system,mathematical models of MIMO channel, MIMO channel capacity and all kinds oftheories, models,coding algorithms of transmit diversity schemes.And then areOFDM-CDMA technology and MIMO-OFDM system.Based on the technologiesabove, transmit diversity scheme is combined with multi-carrier OFDM technology,and space-time spreading(STS) is expanded from single carrier to multi-carrier to codewith space,time and frequency resulting in a space-time-frequency spreading(STFS)codingarithmetic.Andthemost simple STFS whichhas2 TX ,1 R Xand 2carriers isdesigned. Then M TT X, M RRX and NC carriers STFS is gived according to theruleof the most simple STFS. The basic framework of the corresponding transmittersand receivers for STFS are showed, and several combination quomodos for STFS arepresented. At last,the frequencyspectrum efficiencyand error probability of STFS areanalysed,and thevalidityofSTFSisprovedbysimulation.STFS is a good coding arithmetic which is simple and easy to realize. Moreimportantly STFS has higher diversity order and encoding gain than STS at the samesymbol rate. It can repel channel fading , improve data rate and wireless systemcapacity availability, stand against frequency selectivity fading, eliminate theintersymbol interference. It is an ideal coding arithmetic for modern mobilecommunication.