基于扩频码周期性的单通道直扩通信半盲分离抗干扰算法

为克服传统盲源分离抗干扰方法需要多副接收天线这一技术瓶颈,提出一种单通道下基于扩频码周期性的直扩通信半盲分离抗干扰算法。该方法基于扩频码的周期性,利用符号级过采样,把单通道多径慢衰落信道模型转化为多通道瞬时混合模型,同时将训练序列作为先验信息以约束条件的形式引入到盲分离代价函数中,直接从混合信号中提取出期望用户数据,而达到抗干扰的目的。仿真结果表明,在多址干扰和单/多音干扰下,当信干比为-60dB时,随着归一化信噪比Eb/N0的增加,未分离信号的误码率几乎不变,并在10e-0.3附近波动,而经过所提抗干扰算法处理后的信号误码率逐渐降低,并最终稳定在10e-4~10e-5。

Exploiting periodicity of spread spectrum code in anti-jamming algorithm based on single channel semi-blind source separation for direct sequence spread spectrum communication

An anti-jamming algorithm based on single channel semi-blind source separation by exploiting the periodicity of the spread spectrum code for direct sequence spread spectrum (DSSS) communication is presented to overcome the technical bottleneck of traditional anti-jamming methods based on blind source separation (BSS) which need more receive antennas. Firstly, the single channel of DSSS communication’s multipath slow fading channel model is transformed into a multi channel instantaneous mixture model by symbol level oversampling based on the periodicity of the spread spectrum code. Then, training sequence is introduced as a priori information to the cost function of BSS in the constraints form to extract the expected user data from the mixed signal directly, which finally achieves the goal of anti jamming. Simulation results show that in the condition of jamming such as the multiple access jamming and single tone/ multi-tone jamming, when the signal to jamming ratio fixes to -60 dB. with the increasing of the normalized signal to noise ratio, the bit error rate of the unseparated signal is almost constant and fluctuates in the vicinity of 10e-0.3. while the bit error rate of the proposed algorithm gradually decreases, and finally stays between 10e-4~10e-5.