Self Organization of Tilts in Relay Enhanced Networks: A Distributed Solution
Self Organization of Tilts in Relay Enhanced Networks: A Distributed Solution
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DOI：
10.1109/twc.2014.011614.130299
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发表时间：
2014-02
影响因子：
10.4
通讯作者：
A. Imran;M. Imran;A. Abu-Dayya;R. Tafazolli
中科院分区：
文献类型：
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作者：
A. Imran;M. Imran;A. Abu-Dayya;R. Tafazolli
尽管物理层研究多年，中继的容量增强潜力受到基站（BS）-中继站（RS）链路所需的额外频谱的限制。本文提出了一种新的分布式解决方案，而不是利用系统级的角度来看。建立在一个现实的系统模型与即兴RS部署，我们开发了一个分析框架的倾斜优化，可以动态地最大限度地提高频谱效率的BS-RS和BS-用户链路在线的方式。为了获得分布式自组织解决方案，大规模的系统范围内的优化问题被分解成局部小规模的子问题，通过应用在生物系统中的自组织的设计原则。局部子问题是非凸的，但具有非常小的规模，可以通过标准的非线性优化技术，如序列二次规划来解决。通过对LTE-A型系统的广泛模拟来评估所开发的解决方案的性能，并将其与许多基准进行比较，包括通过蛮力获得的集中式解决方案，这也给出了评估最优性差距的上限。结果表明，所提出的解决方案可以提高平均频谱效率高达50%相比，固定倾斜，可以忽略不计的信令开销。所提出的解决方案的主要优点是其自治和分布式实现的潜力。
Despite years of physical-layer research, the capacity enhancement potential of relays is limited by the additional spectrum required for Base Station (BS)-Relay Station (RS) links. This paper presents a novel distributed solution by exploiting a system level perspective instead. Building on a realistic system model with impromptu RS deployments, we develop an analytical framework for tilt optimization that can dynamically maximize spectral efficiency of both the BS-RS and BS-user links in an online manner. To obtain a distributed self-organizing solution, the large scale system-wide optimization problem is decomposed into local small scale subproblems by applying the design principles of self-organization in biological systems. The local subproblems are non-convex, but having a very small scale, can be solved via standard nonlinear optimization techniques such as sequential quadratic programming. The performance of the developed solution is evaluated through extensive simulations for an LTE-A type system and compared against a number of benchmarks including a centralized solution obtained via brute force, that also gives an upper bound to assess the optimality gap. Results show that the proposed solution can enhance average spectral efficiency by up to 50% compared to fixed tilting, with negligible signaling overheads. The key advantage of the proposed solution is its potential for autonomous and distributed implementation.