In this paper, a proposal to improve the reliability of a downlink multiuser (MU) MIMO transmission scheme is investigated with the use of a new approach in orthogonal space-time block codes (OSTBC) and network coding with a superposition modulated system and side information. With the new encoded OSTBC approach, diversity is offered where each user receives all other users' symbols, which allows the recovery of symbols in several ways. In addition, multiple users can be accommodated with the same resource, which is quite useful in a wireless system where resources are always restricted. By employing superposition modulation, the side information needed for error recovery can be transmitted over the same resource used for the normal information frame. In addition, the proposed system exploits diversity through a novel technique of sub-constellation alignment-based signal combining for efficient side information dissemination. A detailed analysis of the new OSTBC approach is carried out. It is shown that the performance of the MU-MIMO system can be improved significantly in terms of block and frame error rates (BLER, FER) considered as reliability measures. By accommodating a reasonable number of multiple users, high reliability is achieved at the expense of the rate. To compensate for the low rate, conventional OSTBC can be considered and simulation results are shown, where, as a penalty to pay, multiple orthogonal resources are required.

中文翻译：

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高可靠性下行链路 MU-MIMO：新的 OSTBC 方法和叠加调制边信息

在本文中，通过使用正交空时分组码 (OSTBC) 和具有叠加调制系统和边信息的网络编码的新方法，研究了提高下行链路多用户 (MU) MIMO 传输方案可靠性的建议. 使用新的编码 OSTBC 方法，在每个用户接收所有其他用户的符号的情况下提供了多样性，这允许以多种方式恢复符号。此外，同一资源可以容纳多个用户，这在资源总是受限的无线系统中非常有用。通过采用叠加调制，错误恢复所需的边信息可以在用于正常信息帧的相同资源上传输。此外，所提出的系统通过一种基于子星座对齐的新型信号组合技术来利用多样性，以实现有效的辅助信息传播。对新的 OSTBC 方法进行了详细分析。结果表明，MU-MIMO 系统的性能可以在误块和帧错误率（BLER，FER）方面得到显着提高，作为可靠性措施。通过容纳合理数量的多用户，以牺牲速率为代价实现高可靠性。为了补偿低速率，可以考虑传统的 OSTBC 并显示仿真结果，其中作为代价，需要多个正交资源。结果表明，MU-MIMO 系统的性能可以在误块和帧错误率（BLER，FER）方面得到显着提高，作为可靠性措施。通过容纳合理数量的多用户，以牺牲速率为代价实现高可靠性。为了补偿低速率，可以考虑传统的 OSTBC 并显示仿真结果，其中作为代价，需要多个正交资源。结果表明，MU-MIMO 系统的性能可以在误块和帧错误率（BLER，FER）方面得到显着提高，作为可靠性措施。通过容纳合理数量的多用户，以牺牲速率为代价实现高可靠性。为了补偿低速率，可以考虑传统的 OSTBC 并显示仿真结果，其中作为代价，需要多个正交资源。