基于短包通信的NOMA下行链路安全传输

面向物联网业务中的低时延需求,将短包通信(SPC)和非正交多址接入(NOMA)技术相结合,针对存在窃听者的情况研究多用户NOMA系统中的安全传输问题。以最大化弱用户的安全吞吐量为目标,考虑用户译码错误概率约束、总功率约束和功率分配约束,提出了一种低复杂度的功率分配方案实现系统安全传输。为解决复杂的目标函数和不可靠的串行干扰消除(SIC)技术带来的问题,首先证明约束条件在取得最优解时的紧约束性,在最大译码错误概率约束下,对功率约束进行转化和计算,得到强用户发射功率范围,推导出基站向强用户的发射功率搜索集;然后利用一维搜索算法对功率进行分配,实现弱用户吞吐量最大化。仿真结果证明,所提方案可有效提高系统中弱用户的安全吞吐量。

Secure transmission for NOMA downlink based on short packet communication

For the low-latency requirements of Internet of things(IoT)business,short packet communication(SPC)and non-orthogonal multiple access(NOMA)were combined to study the problem of secure transmission in the multi-user NOMA system with eavesdroppers.With the maximizing the secure throughput of weak uses as the objective,considering the user decoding error probability constraint,total power constraint and power allocation constraint,a low-complexity power allocation algorithm was proposed to realize secure transmission.In order to solve the problem caused by complex objective function formula and unreliable serial interference cancellation(SIC)technology,the proof that the compactness of the constraints was necessary to find the optimal solution.Under the constraint of maximum decoding error probability,the power constraint was transformed and calculated to obtain the strict limit of transmitting power for strong users,and the transmit power search set from base station to strong user was derived.Then,the one-dimensional search algorithm was used to allocate power resources to maximize the throughput of weak users.Simulation results prove that the proposed algorithm can effectively improve the security throughput of weak users in the system.