Throughput Optimization, Spectrum Allocation, and Access Control in Two-Tier Femtocell Networks
Throughput Optimization, Spectrum Allocation, and Access Control in Two-Tier Femtocell Networks
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DOI：
10.1109/jsac.2012.120406
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发表时间：
2012-04-01
影响因子：
16.4
通讯作者：
Kountouris, Marios
中科院分区：
文献类型：
--
作者：
Cheung, Wang Chi;Quek, Tony Q. S.;Kountouris, Marios
在宏蜂窝网络中部署毫微微蜂窝基站是增加网络容量和覆盖范围的一种经济有效的方式。然而，由于层间和层内干扰的存在以及毫微微小区的自组织操作，这种部署是具有挑战性的。受OFDMA灵活的子信道分配能力的启发，本文研究了双层网络中的频谱分配效果，其中宏小区采用封闭接入策略，而毫微微小区可以在开放或封闭接入中工作。通过引入一个易于处理的模型，我们得出了不同的频谱分配和毫微微蜂窝接入策略下的成功概率为每一层。特别是，我们考虑联合子信道分配，其中整个频谱是由两层共享，以及不相交的子信道分配，其中不相交的子信道集被分配给两层。我们制定的吞吐量最大化问题的成功概率和每层的最低速率的服务质量的约束，并提供见解的最佳频谱分配。我们的研究结果表明，与封闭接入的毫微微蜂窝基站，优化的联合和不相交的子信道分配提供了最高的吞吐量之间的所有计划在稀疏和密集的毫微微蜂窝网络，分别。对于开放接入毫微微蜂窝基站，优化的联合子信道分配为所有毫微微蜂窝基站密度提供了最高可能的吞吐量。
The deployment of femtocells in a macrocell network is an economical and effective way to increase network capacity and coverage. Nevertheless, such deployment is challenging due to the presence of inter-tier and intra-tier interference, and the ad hoc operation of femtocells. Motivated by the flexible subchannel allocation capability of OFDMA, we investigate the effect of spectrum allocation in two-tier networks, where the macrocells employ closed access policy and the femtocells can operate in either open or closed access. By introducing a tractable model, we derive the success probability for each tier under different spectrum allocation and femtocell access policies. In particular, we consider joint subchannel allocation, in which the whole spectrum is shared by both tiers, as well as disjoint subchannel allocation, whereby disjoint sets of subchannels are assigned to both tiers. We formulate the throughput maximization problem subject to quality of service constraints in terms of success probabilities and per-tier minimum rates, and provide insights into the optimal spectrum allocation. Our results indicate that with closed access femtocells, the optimized joint and disjoint subchannel allocations provide the highest throughput among all schemes in sparse and dense femtocell networks, respectively. With open access femtocells, the optimized joint subchannel allocation provides the highest possible throughput for all femtocell densities.