放大转发中继系统中基于SCMA的能效资源分配方案

放大转发中继系统中, 以提升能效为目标, 在保障各用户的最小速率需求下, 提出一种子载波顺序配对以及稀疏码分多址(sparse code division multiple access, SCMA)码本功率联合资源分配算法。将能效资源分配建模为一个混合型整数优化问题, 并将其拆分为子载波配对和码本及功率分配两个独立的子问题。首先, 预设码本和功率分配, 基于能效对子载波进行配对。然后, 在子载波固定配对的情况下, 基于能效码本采用最优信道选择的分配方法, 功率问题转化为含有参量的凹函数, 构建拉格朗日函数进行迭代求解。最后，码本和功率交替迭代优化直至收敛。仿真表明, 所提算法较其他方案可以提升约29%的系统平均能效, 同时也保证了每个用户的最小速率需求。

SCMA-based energy efficiency resource allocation scheme in amplify-forward relay system

In the amplify-forward relay system, to content the goal of improving energy efficiency, a sub-carrier sequential pairing and a sparse code division multiple access (SCMA) codebook power joint resource allocation algorithm is proposed while ensuring the minimum rate requirements of each user. The energy efficiency resource allocation is modeled as a mixed integer optimization problem, and is divided into two independent sub-problems of sub-carrier pairing and codebook and power allocation. Firstly, the codebook and power allocation are presented, and the sub-carriers is paired based on energy efficiency.Then, in the case of fixed sub-carrier pairing, the optimal channel selection allocation method based on the energy efficiency codebook is used to transform the power problem into a concave function which contains important parameters. The concave function can be solved by Lagrangian function iteratively. Finally, codebook and power alternate iterative optimization until convergence. Simulation results show that the proposed algorithm can improve the average energy efficiency of the system by about 29% compared with other schemes, while also ensuring the minimum speed requirement of each user.