摘要
提出了一种适用于TDD上行链路的基于预均衡和正交循环码的M元MC-CDMA系统.各移动用户使用正交循环码进行M元扩频,降低了选码的难度.由于上行链路的M元MC-CDMA信号在传输前经过了预均衡处理,使得各用户信号在到达基站后能够保持良好的正交性.在将基站接收信号分别与各用户原型扩频码镜像序列的OFDM调制结果相乘后,利用OFDM解调器可同时完成M元解扩和多载波解调.研究结果表明,本系统的频带利用率和计算复杂度均优于传统的M元MC-CDMA系统.
A novel M-ary MC-CDMA system in uplink TDD mode is proposed based on orthogonal cyclic codes and pre-equalization. At the transmitter, every mobile user uses the orthogonal cyclic codes as spreading codes, which reduces the spreading codes selection difficulty of the M-ary MC-CDMA system. In order to keep a good orthogonal characteristic among all users＇ signals, a pre-equalizer is employed to process the M-ary MC-CDMA signal before being transmitted. The received signal is multiplied by the local sequence, and then the proposed scheme achieves the M-ary despread spectrum and OFDM demodulation at the same time. The results show that the proposed scheme has better bandwidth efficiency and lower computation complexity than traditional M-ary MC-CDMA systems.
出处
《西安电子科技大学学报》
EI
CAS
CSCD
北大核心
2007年第2期199-204,共6页
Journal of Xidian University
基金
国家自然科学基金(60572148)
国防科技重点实验室基金(51473020105JB3203)
陕西省自然科学基金资助(2006F22)
关键词
MC-CDMA
M元扩频
正交循环码
预均衡
MC-CDMA
M-ary spread spectrum
orthogonal cyclic codes
pre-equalization
