基于公平性的D2D时隙调度算法

针对设备到设备（D2D）通信资源分配中的时隙调度时延以及信道增益变化导致吞吐率下降的问题，提出了一种公平性时隙调度（FTDS）算法。首先，基于频谱复用模式建立系统模型，并归纳为一组合优化问题；然后，在模型的次优求解中，FTDS算法将调度周期划分为多个等长的时隙，根据优先级策略将D2D用户分配至不同时隙调度，从而适应D2D用户多于蜂窝用户的应用场景；同时，为了权衡服务质量（QoS）与系统吞吐率的关系，构造一满足性权值与传输速率相互制约，共同决定用户调度优先级。仿真实验中，FTDS算法相比TDS、RANDOM算法，吞吐率平均增幅分别达到11.09%和40.64%，且FTDS算法下D2D用户被调度频次累积分布更为集中；同时，相比TDS算法调度时延最大降低31.22%。仿真实验表明，FTDS算法拥有更优的吞吐率性能、更公平的调度机制、更小的调度时延。

Device to device time division scheduling algorithm based on fairness

To solve the problem of throughput degradation caused by slot scheduling delay and channel gain variation in Device to Device (D2D) communication resource allocation, a Fairness Time Division Scheduling (FTDS) algorithm was proposed. Firstly, the system model was established based on the spectrum reuse mode, and was transformed to a combinatorial optimization problem. Then, in the sub-optimal solution of the model, the scheduling period was divided into several equal-length slots by the FTDS algorithm, and the D2D users were assigned to different time divisions according to the priority policy, for the application scenario that D2D users are more than cellular users. Meanwhile, to balance Quality of Service (QoS) and system throughput, a satisfaction weight was constructed to restrict transmission rate, jointly determined the user scheduling priority. In the simulation, compared with TDS and RANDOM algorithm, the average throughput increase of FTDS algorithm was 11.09% and 40.64% respectively, and cumulative distribution of D2D scheduling frequency was more centralized by FTDS algorithm; meanwhile, the time delay of FTDS algorithm decreased as much as 31.22% compared with TDS.The simulation results show that FTDS algorithm has better throughput performance, more fair scheduling mechanism and smaller scheduling time delay.