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针对多载波码分多址(MC CDMA)系统传统频域符号检测方法解码效率低的问题,提出了基站使用任意阵MC CDMA系统的特殊等效空时直接序列码分多址模型,其特点是定义了具有循环卷积结构的特征波形,从空时联合角度刻画了矢量信道特征,克服了频域模型不能理想描述矢量信道的痼疾.同时,为系统构造了基于上行矢量信道冲激响应盲估计的最小均方误差等效空时多用户检测器,其性能是线性最优的.仿真结果表明,当系统信噪比为8dB并且负载因子(即活动用户数与扩频增益之比)不超过85%时,即使单天线也比4天线传统频域等增益合并符号检测方法的解码效率至少要高出20dB.
Aiming at the problem of low decoding efficiency of traditional frequency-domain symbol detection in multi-carrier code division multiple access (MC CDMA) system, this paper proposes a special equivalent space-time direct sequence code division multiple access model using arbitrary MC MCS in base stations The characteristic waveforms with convolutional convolution are defined, and the characteristics of vector channel are described from the joint space-time view, overcoming the problem that the frequency domain model can not describe the vector channel ideally.At the same time, blind estimation based on uplink vector channel impulse response , The performance of which is linear optimal.The simulation results show that when the system SNR is 8dB and the load factor (ie, the ratio of active users to spreading gain) does not exceed 85%, even single antenna than 4 antenna traditional frequency domain equalization symbol detection method decoding efficiency at least 20dB higher.