We propose novel deep joint source-channel coding (DeepJSCC) algorithms for wireless image transmission over multi-input multi-output (MIMO) Rayleigh fading channels, when channel state information (CSI) is available only at the receiver. We consider two different schemes; one exploiting the spatial diversity and the other exploiting the spatial multiplexing gain of the MIMO channel, respectively. For the former, we utilize an orthogonal space-time block code (OSTBC) to achieve full diversity and increase the robustness against channel variations. In the latter, we directly map the input to the antennas, where the additional degree of freedom can be used to send more information about the source signal. Simulation results show that the diversity scheme outperforms the multiplexing scheme for lower signal-to-noise ratio (SNR) values and a smaller number of receive antennas at the AP. When the number of transmit antennas is greater than two, however, the full-diversity scheme becomes less beneficial. We also show that both the diversity and multiplexing schemes can achieve comparable performance with the state-of-the-art BPG algorithm delivered at the instantaneous capacity of the MIMO channel, which serves as an upper bound on the performance of separation-based practical systems.

翻译：我们针对多输入多输出（MIMO）瑞利衰落信道上的无线图像传输，提出了一种新颖的深度联合源信道编码（DeepJSCC）算法，其中信道状态信息（CSI）仅在接收端可用。我们考虑两种不同的方案：一种利用MIMO信道的空间分集增益，另一种利用其空间复用增益。对于前者，我们采用正交空时分组码（OSTBC）实现全分集，增强对信道变化的鲁棒性。在后者中，我们将输入直接映射到天线上，利用额外的自由度传输更多源信号信息。仿真结果表明，在较低信噪比（SNR）值和接入点（AP）接收天线数较少时，分集方案优于复用方案。然而，当发射天线数大于二时，全分集方案的收益降低。我们还表明，两种方案均能达到与基于MIMO信道瞬时容量（作为分离式实际系统的性能上界）的先进BPG算法相当的性能。