下一代无线通信网络资源优化分配理论与关键技术

Driven by the increasing popularity of wireless broadband services, future wireless networks are expected to provide high-data-rate services. As an important technology that is applied to achieve higher data rate and better quality of service (QoS), wireless resource allocation has drawn a lot of attentions in recent years. Various 4G technologies such as Wimax and LTE have converged to the use of WRA (Wireless Resource Allocation). One major advantage of WRA is that it enables all users dramatically adapt the allocation of wireless resource based on the users' channel conditions and quality of service (QoS) requirements. Thanks to the recent development of wireless data and multimedia applications, one commonly pursued target of WRA is to optimize a system-wide efficiency metric, such as a system utility function based on throughput and delay. Optimal resource allocation is extremely difficult to achieve despite its paramount importance, mainly because the optimization problem is in general highly non-convex due to the complicated interference coupling between links. Finding the global optimal solution had eluded researchers and remained open for the past decade. The lack of a global optimization algorithm renders it impractical to evaluate the performance of existing heuristics in terms of how close they get to the optimal solution. Furthermore, without knowing the global optimal resource allocation, there lack important guidelines for the design of good heuristics that may find wide application in real network systems. It is therefore of utmost research and practical interest to devise efficient algorithms to solve the long-standing open problem in a global optimal manner. A goal of this project is to find global optimal solutions to a variety of non-convex wireless resource allocation problems based on the recent advances in monotonic optimization. Instead of tackling the non-convexity issue head on, we bypass non-convexity by exploiting the monotonic nature of the resource allocation problem. Of particular interest are three key issues to be investigated: (i) the establishment of a monotonic optimization framework for non-convex resource allocation problems; (ii) the generalization of the proposed framework to joint scheduling and resource allocation in dense networks; (iii) the development of low-complexity algorithms by exploiting the special features of the formulated problems. To the best of our knowledge, this is a first attempt at exploiting the hidden monotonicity to solve a non-convex engineering problem efficiently. We believe the new framework opens up many interesting avenues for researchers to devise global optimization algorithms for problems that have been open for years, as most optimization problems in communications and networking are essentially monotonic, although not convex.

随着数据通信与多媒体业务需求的发展，用户对无线通信网络的服务性能要求越来越高，无线资源（包括传输功率、时隙等）却日趋紧张。无线资源优化分配研究是4G/5G通信技术研究中的核心模块，其目的是尽可能高效地利用受限的无线资源以保证无线通信网络用户的服务性能。然而，如何以受限的无线资源大幅度提高网络服务性能是一个巨大的挑战。为了应对这一挑战，本项目的主要目标是从系统和网络的角度探索无线资源的高效利用机理与方法。具体研究内容包括：从网络系统角度探索未来无线通信网络服务性能的衡量机制；采用合适的数学模型描述服务性能与无线资源分配的关系；利用服务性能与数据率的这一单调性关系，提出一种全新的"基于单调性的资源优化分配"方案。本项目的成功完成将在理论基础和实际应用层面有效解决无线通信网络中的受限资源优化分配问题，从而保证未来无线通信网络多样性服务的服务质量，将极大地推动4G/5G无线通信系统的普及与发展。

随着数据通信与多媒体业务需求的发展，用户对无线通信网络的服务性能要求越来越高，无线资源（包括传输功率、时隙等）却日趋紧张。无线资源优化分配研究是4G/5G通信技术研究中的核心模块，其目的是尽可能高效地利用受限的无线资源以保证无线通信网络用户的服务性能。然而，无线网络的密集化导致无线链路之间的干扰更加复杂严重，无线资源的管理在功率，子载波、接入点、传输时隙等多个维度紧密耦合。因此，针对大量无线链路的多维度、混合型无线资源优化管理，成为密集无线网络的核心研究问题之一。此类研究问题不仅规模大、实时性要求，使得暴力搜索难以适用，而且往往具有节点非合作，优化目标非凸，变量连续-离散混合的特性，使得运筹学理论中已有的最优化工具难以获得理想的性能保证，无线网络资源优化管理在理论上实现存在一定难度。本项目围绕上述问题，以无线资源（包括用户传输功率与用户工作时隙）优化分配策略设计为导向，通过采用优化领域最新的单调性优化理论，对无线资源优化分配问题进行了研究。.本项目的主要研究成果包括：一、针对无线资源分配中的非凸优化问题，通过发掘类Shannon型资源-目标函数的单调性特征，提出了一种锯齿状覆盖逼近的低复杂度的优化方法，解决了长期困扰无线网络的非凸资源优化问题；二、针对无线网络中用户接入管理问题涉及连续、离散混合优化变量的难点，提出了密集无线网络中大规模离散变量基于竞价的随机学习搜索优化，极大降低了问题的搜索维度；三、分别从异构网络能量服务效益角度、以及高动态网络感知和“空时频能”多维资源的机会式使用角度，建立高动态多维度多目标的协同资源优化调度理论和方法，从而实现具有能量-频率使用效率保障的异构网络节能绿色通信。在过去四年的研究中，超额完成了研究计划，取得了一系列有特色的创新性成果：共完成SCI 收录论文15篇，EI收录期刊论文2篇，EI 会议论文16篇，获得浙江省自然科学奖二等奖一项，最佳国际会议论文奖3项目，培养硕士研究生3人次。同时，10余人次参加国际通信会议进行学术交流以及多人多次参加国内举办的国际通信会议并作大会报告。