This paper proposes a coding framework for capacity-region-achieving sparse regression (SR) codes over MIMO multiple-access channels (MIMO-MAC), where a single SR code is used for each user at the transmitter. With random semi-unitary dictionary matrices applied for encoding, multiple-access OAMP (MA-OAMP) enables reliable parallel interference cancellation (PIC) at the receiver. Theoretically, an optimal coding principle with the MA-OAMP receiver, which achieves the sum capacity and, in combination with time sharing, achieves the entire capacity region, is established as the guiding principle for designing capacity-region-achieving codes. Accordingly, a coding scheme for capacity-region-achieving SR codes is proposed via proper power allocation over the position-modulated signals.

翻译：本文提出了一种适用于MIMO多址信道（MIMO-MAC）的容量域可达稀疏回归（SR）编码框架，其中每个用户在发射端使用独立的SR码。通过采用随机半酉字典矩阵进行编码，多址接入OAMP（MA-OAMP）接收机能够实现可靠的并行干扰消除（PIC）。理论上，本文建立了以MA-OAMP接收机实现和容量，并结合时间共享实现整个容量域的最优编码准则，该准则被确立为设计容量域可达码的指导原则。据此，通过对位置调制信号进行合理的功率分配，本文提出了一种容量域可达SR编码的编码方案。