We show that spatially coupled low-density parity- check (LDPC) codes yield robust performance over changing intersymbol interfere (ISI) channels with optimal and suboptimal detectors. We compare the performance with classical LDPC code design which involves optimizing the degree distribution for a given (known) channel. We demonstrate that these classical schemes, despite working very good when designed for a given channel, can perform poorly if the channel is exchanged. With spatially coupled LDPC codes, however, we get performances close to the symmetric information rates with just a single code, without the need to know the channel and adapt to it at the transmitter. We also investigate threshold saturation with the linear minimum mean square error (LMMSE) detector and show that with spatial coupling its performance can get remarkably close to that of an optimal detector for regular LDPC codes.

翻译：我们证明，空间耦合低密度奇偶校验（LDPC）码在变码间干扰（ISI）信道上，采用最优和次优检测器时均能实现鲁棒性能。我们将此性能与经典LDPC码设计（需要针对给定（已知）信道优化度分布）进行了比较。我们证明，这些经典方案尽管针对特定信道设计时表现优异，但若信道发生变化，其性能可能显著下降。而采用空间耦合LDPC码，只需单一码字即可获得接近对称信息率的性能，无需在发射端知晓信道并自适应调整。我们还研究了线性最小均方误差（LMMSE）检测器的阈值饱和现象，并表明通过空间耦合，其性能可极为接近规则LDPC码最优检测器的水平。