Receivers with joint channel estimation and signal detection using superimposed pilots (SP) can achieve high transmission efficiency in orthogonal time frequency space (OTFS) systems. However, existing receivers have high computational complexity, hindering their practical applications. In this work, with SP in the delay-Doppler (DD) domain and the generalized complex exponential (GCE) basis expansion modeling (BEM) for channels, a message passing-based SP-DD iterative receiver is proposed, which drastically reduces the computational complexity while with marginal performance loss, compared to existing ones. To facilitate channel estimation (CE) in the proposed receiver, we design pilot signal to achieve pilot power concentration in the frequency domain, thereby developing an SP-DD-D receiver that can effectively reduce the power of the pilot signal and almost no loss of CE accuracy. Extensive simulation results are provided to demonstrate the superiority of the proposed SP-DD-D receiver.

翻译：采用叠加导频（SP）进行联合信道估计与信号检测的接收器可在正交时频空（OTFS）系统中实现高传输效率。然而，现有接收器计算复杂度高，阻碍了其实际应用。本文针对时延-多普勒（DD）域中的叠加导频及基于广义复指数（GCE）基扩展模型（BEM）的信道建模，提出了一种基于消息传递的SP-DD迭代接收器，与现有接收器相比，该接收器在几乎不损失性能的情况下大幅降低了计算复杂度。为便于所提接收器中的信道估计（CE），我们设计了导频信号以实现频域导频功率集中，进而开发了一种SP-DD-D接收器，该接收器可有效降低导频信号功率且几乎不损失信道估计精度。大量仿真结果验证了所提SP-DD-D接收器的优越性。