2-Dimensional OVSF Spread/Chip-Interleaved CDMA
2-Dimensional OVSF Spread/Chip-Interleaved CDMA
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DOI：
10.1093/ietcom/e89-b.12.3363
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发表时间：
2006-12
期刊：
影响因子：
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通讯作者：
Le Liu;F. Adachi
中科院分区：
文献类型：
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作者：
Le Liu;F. Adachi
多址干扰（MAI）限制了CDMA上行链路传输的误比特率（BER）性能。在本文中，我们提出了一种广义的码片交织CDMA与2维（2D）扩展使用正交可变扩频因子（OVSF）码，以尽量减少多址干扰的影响，并实现最大的可用的时域和频域分集增益。我们提出了二维扩频的码分配，为用户提供灵活的多速率数据传输。仿真结果表明，在准同步DS或MC-CDMA上行链路中，联合使用二维OVSF扩频和码片交织可以实现无多址干扰传输，因此可以采用基于MMSE准则的单用户频域均衡进行信号检测。本文从理论上分析了时频选择性衰落多用户信道中的误码率性能，并通过数值计算和计算机仿真进行了评估。
Multiple-access interference (MAI) limits the bit error rate (BER) performance of CDMA uplink transmission. In this paper, we propose a generalized chip-interleaved CDMA with 2-dimensional (2D) spreading using orthogonal variable spreading factor (OVSF) codes to minimize the MAI effects and achieve the maximum available time-and frequency-domain diversity gains. We present the code assignment for 2D spreading to provide users with flexible multi-rate data transmission. A computer simulation shows that by the joint use of 2D OVSF spreading and chip-interleaving, MAI-free transmission is possible for the quasi-synchronous DS- or MC-CDMA uplink, and hence the single-user frequency-domain equalization based on the MMSE criterion can be applied for signal detection. The BER performance in a time- and frequency-selective fading multiuser channel is theoretically analyzed and evaluated by both numerical computation and computer simulation.