5G大连接场景下混合多址随机接入

A Hybrid Random Access for Massive Connections in 5G systems

为了提高5G系统的终端接入数量,提出了一种混合多址随机接入机制,使终端能够根据预测的信噪比和预定义的切换门限选择正交多址或非正交多址的方式进行随机接入.为了提高干扰消除接收机的性能,在非正交随机接入时采用功率回退的方法保证基站收到不同功率的叠加信号.此外,理论分析了混合多址随机接入的接入性能,并给出了数值仿真结果和实际系统仿真结果.仿真结果表明,与单一正交或非正交多址接入机制相比,混合多址接入大大提高了网络的终端接入数.

In order to increase the number of access in the fifth-generation systems,a hybrid multiple random access（RA） scheme is proposed. The proposed scheme allows user equipments to select the orthogonal multiple access（OMA） RA or the non-orthogonal multiple access（NOMA） RA by a predicted signal noise ratio and predefined thresholds. In order to improve the performance of interference cancelation,a power back-off scheme is applied to guarantee the received powers of overlapped signals are diverse. In addition,the access performance of hybrid RA is theoretically analyzed. In the simulation,both numerical results and simulation results in practical systems are provided. Simulation results show that the proposed RA procedure significantly improves the number of successful access compared with single OMA RA or NOMA RA.