解析受信の大容量陸上移動通信システムdiffCDMAへの適用と, そのマルチレイレイレーフェーディング伝播路特性

Abstract

The differential coding CDMA (diffCDM) is verified here to conquer the fatal transmission error when communications are carried from high speed running vehicles through such urban environment as rapid multi-rap Rayleigh channels. With bases of introducing differential coding into the primary modulation and employing analytic receiving for primary differential demodulation, the proposing diffCDMA improves transmission characteristics of such similar CDMA systems as IS95 and WcdmaOne IMT2000 when communications carried from more than 100 mile/h mobiles even if through multi-ray environment. Previously differential coding primary modulation is not considered to be able to stand on CDMA owing to requiring strict sense synchronization in demodulation, which is suffered from bit error under such rapid multi-ray Rayleigh fading. However, it becomes to be able in high speed and high capacity transmission after the analytic receiving being adopt into CDMA systems. In the demodulation procedure of the diffCDMA, received waves are at first detected after multi-ray propagation with certain inevitable errors both in phase and frequency of the recovered carrier for the pseudo synchronization primary demodulation during the analytic receiving.