Successive Interference Cancellation Algorithm Based on Gram-Schmidt Orthogonalization Algorithm
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摘要: 基于Gram-Schmidt正交化法,提出了一种改进的串行干扰消除算法.不同于传统的串行干扰消除算法,该算法运用Gram-Schmidt正交化法,通过扩频序列获取正交序列作为最优解扩码,使得检测器每一级最强用户的解扩码与其他用户的扩频码所张的子空间正交,从而实现对多址干扰的完全抑制.给出了具有幅度失配的系统误码率近似公式,讨论了幅度失配对检测性能的影响.仿真结果表明,改进算法能有效抑制CDMA系统中的多址干扰,改善系统性能.
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关键词:
- 码分多址(CDMA) /
- 串行干扰消除检测算法 /
- Gram-Schmidt正交化法 /
- 多址干扰 /
- 误码性能
Abstract: A new SIC(successive interference cancellation) algorithm based on the Gram-Schmidt orthogonalization algorithm was presented.Unlike the conventional SIC algorithm,this algorithm uses an optimal despreading sequence,locally generated by the Gram-Schmidt orthogonalization of spreading sequences,to demodulate a received signal in each stage.The despreading code of the strongest user in each stage is orthogonal to the subspace spanned by the spreading code of other users,so that the multiple access interference(MAI) is fully suppressed.An approximate bit error rate(BER) formula with the amplitude mismatch was proposed,and the effect of the amplitude mismatch on the BER performance of CDMA systems was discussed.Simulations show that the new algorithm can effectively cancel MAI and improve the BER performance. -
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