Outage Analysis and Power Allocation for HARQ-CC Enabled NOMA Downlink Transmission
Outage Analysis and Power Allocation for HARQ-CC Enabled NOMA Downlink Transmission
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DOI：
10.1109/glocom.2018.8647914
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发表时间：
2018-12
期刊：
影响因子：
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通讯作者：
Yanqing Xu;Donghong Cai;Fang Fang-Fang;Z. Ding;Chao Shen;Gang Zhu
中科院分区：
文献类型：
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作者：
Yanqing Xu;Donghong Cai;Fang Fang-Fang;Z. Ding;Chao Shen;Gang Zhu
本文旨在设计一种功率分配策略来最小化具有追赶合并的混合自动重发请求(HARQ-CC)系统在严格的用户中断约束下的平均功率消耗。特别是，为了进一步提高系统的频谱效率，引入了非正交多址(NOMA)，并假设基站只知道用户的统计信道状态信息。为了评估支持HARQ-CC的NOMA系统的性能，我们首先分析了每个用户的中断概率。然后，基于所导出的中断概率，通过优化发射功率，考虑了平均功率最小化问题。然而，所得到的停运概率的表达式是非凸的，并且极其复杂，这使得所建立的问题难以处理。为了有效地解决原问题，我们首先用一个易处理的保守近似来逼近它，然后使用基于逐次凸逼近的算法来迭代地处理松弛问题。并且所提出的算法可以保证至少收敛到问题的一个固定点。仿真结果表明了所提出的传输策略的有效性以及所提出的近似方法和算法的近最优性。
In this paper, we aim to design a power allocation strategy to minimize the average consumed power of a hybrid automatic repeat request with chase combining (HARQ-CC) enabled system under a strict outage constraint for each user. In particular, the non-orthogonal multiple access (NOMA) is incorporated to further improve the system spectrum efficiency and we assume the base station only knows the statistical channel state information of the users. To evaluate the performance of the HARQ-CC enabled NOMA system, we first analyze the outage probability of each user. Then, based on the derived outage probabilities, by optimizing the transmit power, an average power minimization problem is considered. However, the attained expressions of the outage probabilities are nonconvex and extremely complicated, and thus make the formulated problem difficult to deal with. To efficiently solve the original problem, we first conservatively approximate it by a tractable one and then use a successive convex approximation based algorithm to handle the relaxed problem iteratively. And the presented algorithm can be guaranteed to converge to at least a stationary point of the problem. The simulation results show the efficacy of the proposed transmission strategy and the near-optimality of the proposed approximation approach and algorithm.