CIF: Small: A Cross-Tier Approach to Interference Management in Wireless Heterogeneous Networks

在异构无线网络中，由于第二层低功率微/微微/飞频基站与高功率宏基站之间的频率共享，干扰已成为主要的性能限制因素。本课题涉及异构无线网络干扰管理的几个理论和实践方面。提出的研究将首先确定在计算上难以处理的干扰管理问题的类别，然后展示如何在问题大小和解决精度的多项式复杂度下近似解决这些问题。特别强调了所提出算法的分布式实现。将开发统一的协层和跨层方法，用于联合用户准入、用户基站关联、功率控制、用户分组以及收发器设计。本研究的核心是共同优化用户-基站关联、发射/接收波束形成、用户调度以及基站子集之间的部分联合传输。该方法将干扰管理问题转化为等效的高维优化问题，并探索可跨基站、用户和频率槽分解的迭代的有效更新。在整个研究过程中，先进的优化技术将是各种干扰管理算法发展的关键。本研究所开发的方法将提供有效的手段，以减轻异构网络中的干扰，并显著提高网络吞吐量和用户服务质量。

In a heterogeneous wireless network, interference has become the dominant performance limiting factor due to frequency sharing between the second tier low powered micro/pico/femto base stations and the high powered macro base stations. This project deals with several theoretical and practical aspects of interference management for the heterogeneous wireless networks.The proposed research will first identify the classes of interference management problems that are computationally intractable, and then show how well they can be approximately solved with a complexity that is polynomial in the problem size and the solution accuracy. Special emphasis is given to the distributed implementation of the proposed algorithms. A unified co-tier and cross-tier approach will be developed for joint user admission, user-base station association, power control, user grouping as well as transceiver design. Central to this study is to jointly optimize user-base station association, transmit/receive beamformers, user scheduling as well as partial joint transmission among a subset of base stations. The proposed approach will transform the interference management problem into an equivalent higher dimensional optimization problem and explore efficient update of iterates that can be decomposed across base stations, users and frequency slots.Throughout this research, advanced optimization techniques will be the key to the development of various interference management algorithms. The methodologies developed in this research will provide effective means to mitigate interference in heterogeneous networks and significantly improve the network throughput as well as the users quality of service.