Research On Adaptive Equalizer In Dedicated Short Range Communication

Nowadays, the ITS has been developed quickly in the world. And DSRC (Dedicated Short Range Communication), as the main technology in this area, was mentioned usually. DSRC can provide the communication link between the vehicle and the road side. The communication channel will be more effective and quickly because of it. Now this technology has the wide application in the Electronic Toll Collection and will affect other area, for example, the Park etc.With the development of integrated circuit and compute technology, it is sure that digital communication should be developed with the much more fast and reliable direction. Toward DSRC technology, bit error and spectrum availability ratio are two main scale targets. Owing to non-ideal normal channel, serious Inter-Symbol Interference(ISI) is generated after the digital signal being transmitted, which is a very disadvantage for correct decision, sequentially communication bit error is increased. Which is not expected and measures should be taken to solve this problem. So, it is necessary for DSRC to add the adaptive equalization to develop the reliabilityAdaptive equalization, from its bringing forward to now, has been widely employed because of its good performance. This paper simply discusses the cause of generating Inter-Symbol Interference based on normal communication channel study. Frequently used equalizer architectures are studied, and computer simulation are made and analyzed for these architectures. Then I design a new equalizer according to the analysis on those architectures. Advantages and disadvantages of kinds of available normal algorithms are compared and analyzed, and then I found a new method to improve the algorithm of CMA. Generally speaking, there are correlations among input signal vectors, A modified CMA is put forward using this kind of correlation, modified CMA and CMA are compared and computer simulation are made and analyzed. The simulation shows that the modified CMA convergent rate is faster than CMA convergent rate.With the characteristic of DSRC, this paper uses the Simulink software to make a simulation of DSRC communication system and its parts, and adds the equalizer to this system. Because of the different location of the equalizer in the system, this paper mainly analyzed two mode of baseband and passband system. And I got the advantages of passband system according to compare the BER and SNR with their pictures made by the software.