LDPC编码的MIMO-OFDM系统中的联合半盲均衡与解码研究

在低密度奇偶校验编码的多输入多输出正交频分复用系统中,针对接收信号存在多天线干扰、多径衰落和加性噪声的问题,提出了不同调制方式下基于线性规划(linear programming, LP)的联合半盲均衡与解码算法。当系统采用高阶正交幅度调制时,提出了新的约束条件,保证了联合解码的正确性。同时利用导频符号对系统子信道进行估计,根据估计出的信道信息,分别给出了传统的Turbo接收机和基于LP的联合检测与解码的仿真结果。实验结果表明，在导频符号数量较少时,现有的基于信道估计信息的检测算法会出现错误地板,而所提的算法则取得了较优的误码性能。

Joint semi-blind equalization and decoding of LDPC coded MIMO-OFDM system

This paper presents the joint semi blind equalization and decoding algorithms based on linear programming (LP) in the low density parity check coded multiple input multiple output orthogonal frequency division multiplexing systems with different modulation methods, in which the signals are affected by multiple antenna interferences, multi path fading and additive noise. When a non affine quadrature amplitude modulation is utilized, some new constraints are developed, which guarantees the correctness of joint decoding. Furthermore, pilot symbols are applied to estimate the channel state information needed in Turbo receiver and joint detection and decoding based on LP. Simulation results indicate that when only a small number of pilots are available, the existing detection techniques based on channel estimation exhibit error floors. In contrast, the proposed receiver performs well in the whole simulated regions.