Power Control in Two-Tier Femtocell Networks
Power Control in Two-Tier Femtocell Networks
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DOI：
10.1109/twc.2009.081386
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发表时间：
2009-08-01
影响因子：
10.4
通讯作者：
Gatherer, Alan
中科院分区：
文献类型：
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作者：
Chandrasekhar, Vikram;Andrews, Jeffrey G.;Gatherer, Alan
在两层蜂窝网络中（由中央宏蜂窝和短距离毫微微蜂窝热点组成）中，跨层干扰通过通用频率复用限制了整体容量。为了量化通用频率复用的远近效应，本文推导了一个基本关系，在给定任何可行毫微微蜂窝基站 SINR 的情况下，提供最大可行的蜂窝信号干扰加噪声比 (SINR)。我们提供链路预算分析，可以在两层网络中实现简单而准确的性能洞察。提出了毫微微小区处的基于分布式效用的SINR自适应，以便减轻宏小区处来自同信道毫微微小区的跨层干扰。 Foschini-Miljanic (FM) 算法是自适应的一个特例。每个毫微微蜂窝基站最大化其各自的效用，包括基于 SINR 的奖励减去所产生的成本（对宏蜂窝的干扰）。数值结果显示，相对于 FM，毫微微蜂窝基站的平均 SINR 提高了 30% 以上。在跨层干扰阻止蜂窝用户获得其 SINR 目标的情况下，提出了一种算法来降低最强毫微微蜂窝干扰源的传输功率。该算法确保蜂窝用户即使在每个蜂窝基站有 100 个毫微微蜂窝基站（具有典型的蜂窝参数）的情况下也能实现其 SINR 目标，并且在最坏情况下只需要毫微微蜂窝基站的 SINR 降低 16%。这些结果激发了在共享频谱的两层网络中需要最小网络开销的功率控制方案的设计。
In a two tier cellular network - comprised of a central macrocell underlaid with shorter range femtocell hotspots - cross-tier interference limits overall capacity with universal frequency reuse. To quantify near-far effects with universal frequency reuse, this paper derives a fundamental relation providing the largest feasible cellular Signal-to-Interference-Plus-Noise Ratio (SINR), given any set of feasible femtocell SINRs. We provide a link budget analysis which enables simple and accurate performance insights in a two-tier network. A distributed utility-based SINR adaptation at femtocells is proposed in order to alleviate cross-tier interference at the macrocell from cochannel femtocells. The Foschini-Miljanic (FM) algorithm is a special case of the adaptation. Each femtocell maximizes their individual utility consisting of a SINR based reward less an incurred cost (interference to the macrocell). Numerical results show greater than 30% improvement in mean femtocell SINRs relative to FM. In the event that cross-tier interference prevents a cellular user from obtaining its SINR target, an algorithm is proposed that reduces transmission powers of the strongest femtocell interferers. The algorithm ensures that a cellular user achieves its SINR target even with 100 femtocells/cell-site (with typical cellular parameters) and requires a worst case SINR reduction of only 16% at femtocells. These results motivate design of power control schemes requiring minimal network overhead in two-tier networks with shared spectrum.