一种增强的GEO卫星CDMA通信系统随机接入方式  

A new random access method for GEO satellite CDMA communication system

作　　者：张丙杰[1] 胡捍英[1] 王大鸣[1] 

机构地区：[1]解放军信息工程大学信息工程学院,河南郑州450002

出　　处：《电路与系统学报》2010年第5期122-126,共5页Journal of Circuits and Systems

基　　金："十一五"国家863计划重大专项(2008AA011100);国家重点项目(2009AA011504)

摘　　要：本文提出了一种适用于GEO卫星CDMA移动通信系统的随机接入方式。该方式参考了S-UMTS中的随机接入方式设计,扩展了其接入帧和接入时隙的长度,并提出了一种新颖的用户随机接入请求的发送策略。通过接入时隙长度的扩展,增大了接入前缀码的个数和前缀的长度,提高了接入消息的扩频增益,从而提高了用户接入的首次捕获概率和接入消息的正确解码概率,降低用户的接入功率,并有效削弱功率攀升问题给系统容量造成的影响。增加了保护间隔的长度,以应对GEO卫星环境下用户之间接入的大时延差问题。本文提出的用户随机接入请求发送策略,有效改善了用户的接入时间性能。It is well known that random access method plays a key role in GEO satellite CDMA communication system, which dominates the performance of access request for users. In this paper, a new random access method is discussed, which ean be used in GEO satellite communication system and others characterized long transmission delay. Based on the random access design in S-UMTS system, a new structure of access frame and slots is proposed and a new procedure of transmitting access request corresponding to the new structure is suggested. In the new structure, the bit error rate of message is improved for the increased spreading ratio of access message and the captured probability of access preamble is increased along with its length and numbers of preamble codes. In order to operate in GEO satellite communication environment with different long transmission delays, the guard interval of the access frame should be increased. Simulation results show that the average access time is remarkably decreased by adopting the proposal transmission procedure of access request.

关 键 词：CDMA ALOHA S-UMTS 接入帧 接入时隙 前缀码 

分 类 号：TN929.53[电子电信—通信与信息系统]