免调度非正交多址技术及其接收机设计

[摘要] 主要探讨5G非正交多址（NOMA）及相应的接收机设计。NOMA在与免调度传输结合时，其收发机的设计除了需要考虑多用户干扰抑制及分集增益的最大化以外，还需要考虑实际的用户检测和识别以及存在碰撞情况下的非理想信道估计。在经典的最小均方误差估计结合串行干扰消除（MMSE-SIC）接收机算法基础上，针对几种不同的免调度实现方案给予相应的解决方案。仿真结果表明：所提方案在误差传播抑制和复杂度降低等方面均有较好的性能增益，在实际系统中可以同时满足免调度及高过载的业务需求。

[关键词] NOMA；免调度传输；海量机器类通信（mMTC）

[Abstract] 5G Non-Orthogonal Multiple Access (NOMA) and the associated receiver design are discussed in this paper. When NOMA is combined with non-scheduled transmission, the suppression of multi-user interference and the maximization of diversity gain should be considered for the design of transceiver. It is also necessary to consider the realistic user detection, identification and the non-ideal channel estimation under contention-based transmission. Based on the classical minimum mean square error - successive interference cancellation (MMSE-SIC) receiver algorithm, the corresponding solutions are given for several different implementation schemes. Simulation results demonstrate that the system performance in terms of error propagation minimization and complexity reduction can be enhanced, and the true grant-free transmission and high overloading capability can be achieved.

[Keywords] NOMA; grant-free transmission; massive machine-type-communications (mMTC)