Font Size: a A A

Research On Technology Of Sychronization And Equalization In High Speed Wireless Digital Communication

Posted on:2003-03-25Degree:DoctorType:Dissertation
Country:ChinaCandidate:L Y LuoFull Text:PDF
GTID:1118360095460122Subject:Communication and Information System
Abstract/Summary:PDF Full Text Request
It has become the important symbol of development that Communication technology and system, and today's digital cellular mobile system and the 3G mobile system in particular, have been developing from wire to wireless, analog to digital, fixed to mobile, low rate to high rate. As enhancement of capacity and transmission rate, it is more important for synchronization and equalization in receiving process, especially for mobile receiver. For digital cellular mobile communication, it becomes complex because of change of channel, FH and TDMA. They make synchronization more complex in non-cooperation receiver Another factor which effects data transmission is the intersymbol interference (ISI). The reason of ISI is the characteristic of a non-ideal channel. In a wireless communication, adaptive transmission and equalization are mainly solution of dealing with ISI. Equalization must be suitable for time varying channel and transmission for time slot of data. In cooperation receiving it can be improved by close-loop of system but it perhaps is the only way to use for non-cooperation receiving. This is one of key problem of dissertation.The equalization needs the training sequence, so the usage of the blind equalizer is necessary. The way and difficulty of realizing blind equalizer in different conditions are different, even it is unrealizable. In the sophisticated channel conditions, the blind equalization and its theory is still the problem which should be studied and improved in the communication field, and is also one of the major contents in the dissertation.The work of the dissertation is raised from the practice engineering, of which the purpose is for the specific application, and it is the general matter of the non-cooperative communication. It is helpful to research for resolving the problem of signal receiving in particular conditions, and can improve understanding of theory and technology in communication system. The major work and innovations done in the dissertation are shown as follows :1. It discusses the problems of the current synchronizations applied in burst mobile communication and the BER effects of the timing offset in different shaping filters is studied. Its conclusion has a significance guiding for design of practical synchronizing scheme and algorithm of the burst mode. There is no report in the current documents;2. The performance of the synchronizing algorithm in the burst transmission is analyzed. The further study of timing synchronization based on the block process has been done. It derives the timing synchronizing algorithm in low rate sampling so as to resolve the problem about receiving of the practical TDMA signal.3. It discussed the Cramer-Rao Bound in band limit channel. We derived the limitation of the estimation performance of the most likelihood timing synchronization and the effects of random data sequence as existing band limited response.The new feedforward timing synchronization based on the most likelihood estimation is given. It realizes the synchronous receiving of mobile packet4. transmission of non-cooperation. 5. The characterization of the multi-path channel and fading channel are discussed, and the characteristic parameters of the channel describing is used to give the channel sorting based on multi-path time spread and Doppler frequence spread. According to the channel sorting, typical equalizer configurations and equalizing algorithm and problems of their applications are discussed.6. The linearization of the part response signal GMSK is presented, which could improve generating of GMSK modulated signals and the most important is that it could improve estimating of channels and the performance of equalizing.7. The new algorithm of the most likelihood MLSE equalizers with the fractional interval is presented. It can improve the adaptation of equalizers for the timing offset. And according to the features of GSM signals, MSLE equalizer algorithm based on sequence estimation is presented. The algorithm and realizing procedure of M...
Keywords/Search Tags:wireless digital communication, timing synchronization, equalization, blind equalization
PDF Full Text Request
Related items