Spectrum allocation in tiered cellular networks
Spectrum allocation in tiered cellular networks
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DOI：
10.1109/tcomm.2009.10.080529
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发表时间：
2009-10
影响因子：
8.3
通讯作者：
V. Chandrasekhar;J. Andrews
中科院分区：
文献类型：
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作者：
V. Chandrasekhar;J. Andrews
双层网络，包括覆盖较短距离热点（例如飞蜂窝、分布式天线或有线中继）的传统蜂窝网络，提供了一种经济上可行的方法来提高蜂窝系统的容量。这种网络的容量限制因素是干扰。由于近距离问题，大蜂窝和飞蜂窝之间的跨层干扰可能会使容量受到抑制，因此在实际应用中，热点应该使用与潜在的附近大功率大蜂窝用户不同的频率信道。集中或协调的频率规划，即使在传统的蜂窝网络中也是困难和低效的，在两层网络中几乎是不可能的。本文提出并分析了采用分频多址（包括OFDMA）的两层网络的最优分散频谱分配策略。所提出的分配在区域频谱效率（ASE）方面是最优的，并且受到合理的服务质量（QoS）要求的约束，从而保证macrocell和femtocell用户至少达到规定的数据速率。结果表明，该分配与QoS要求、热点密度以及来自宏基站和飞基站的同信道干扰有关。提供了设计解释。
Two-tier networks, comprising a conventional cellular network overlaid with shorter range hotspots (e.g. femtocells, distributed antennas, or wired relays), offer an economically viable way to improve cellular system capacity. The capacity-limiting factor in such networks is interference. The cross-tier interference between macrocells and femtocells can suffocate the capacity due to the near-far problem, so in practice hotspots should use a different frequency channel than the potentially nearby high-power macrocell users. Centralized or coordinated frequency planning, which is difficult and inefficient even in conventional cellular networks, is all but impossible in a two-tier network. This paper proposes and analyzes an optimum decentralized spectrum allocation policy for two-tier networks that employ frequency division multiple access (including OFDMA). The proposed allocation is optimal in terms of area spectral efficiency (ASE), and is subjected to a sensible quality of service (QoS) requirement, which guarantees that both macrocell and femtocell users attain at least a prescribed data rate. Results show the dependence of this allocation on the QoS requirement, hotspot density and the co-channel interference from the macrocell and femtocells. Design interpretations are provided.