Decentralized Energy-Efficient Coordinated Beamforming for Multicell Systems
Decentralized Energy-Efficient Coordinated Beamforming for Multicell Systems
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DOI：
10.1109/tvt.2014.2313460
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发表时间：
2014-03
影响因子：
6.8
通讯作者：
Yongming Huang;Shiwen He;Shi Jin;Wenyang Chen
中科院分区：
文献类型：
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作者：
Yongming Huang;Shiwen He;Shi Jin;Wenyang Chen
节能传输是未来无线通信系统的重要组成部分，已受到广泛关注。本文以能量效率为标准，研究了多单元多输入单输出（MISO）下行系统的协调波束形成优化问题，这是目前我们所知的一个尚未解决的问题。我们感兴趣的优化问题是非凸的，并且是分数形式的。为了解决这个问题，我们首先揭示了寻找问题的解相当于在新定义的能效率元组的帕累托边界上寻找一个特定的点。然后，我们提出了一组干扰温度（IT）约束的波束形成优化问题来表征能量效率帕累托边界。在此基础上，提出了两种有效的迭代算法，以达到Pareto最优，从而解决初级问题。我们证明了所提出的算法可以以分散的方式进行，并且保证收敛。然后，将这些算法扩展到使用最坏情况设计来考虑不完全信道状态信息（CSI）。最后给出了数值结果，验证了所提方案的有效性，显示了协调波束形成优化在提高蜂窝网络能量效率方面的巨大潜力。特别是，结果还表明，我们提出的算法通过少量迭代实现了大部分可实现的性能增益，从而在时分双工（TDD）系统中具有有限的回程开销。
Energy-efficient transmission is crucial for future wireless communication systems and has attracted much attention. In this paper, we study coordinated beamforming optimization for multicell multiple-input-single-output (MISO) downlink systems using energy efficiency as a criterion, which is still an open problem to the best of our knowledge. The optimization problem of interest is nonconvex and in a fractional form. To solve it, we first reveal that finding the solution of the problem is equivalent to searching for a particular point on the Pareto boundary of the newly defined energy-efficiency rate tuples. Then, we propose to use a set of interference temperature (IT)-constrained beamforming optimization problems to characterize the energy-efficiency rate Pareto boundary. Based on that, two efficient iterative algorithms are developed to reach the Pareto optimality and thus to solve the primary problem. We show that the proposed algorithms can be carried out in a decentralized manner and are guaranteed to converge. Then, these algorithms are extended to consider imperfect channel state information (CSI) using the worst-case design. Numerical results are finally provided to verify the effectiveness of the proposed schemes and they exhibit the great potential of the coordinated beamforming optimization in improving the energy efficiency of the cellular network. In particular, the results also illustrate that our proposed algorithms achieve most of the achievable performance gain with a small number of iterations and thereby with limited backhaul overhead in a time-division duplexing (TDD) system.