Dynamic spectrum management in packet networks

新的通信技术和服务对电磁频谱产生了爆炸性的需求。无线电频谱是一种有限的资源，其使用由政府颁发许可证。传统上，频谱分配是基于固定的长期频带分配模式，并不一定确保频谱在所有时间、所有领域都得到最有效的利用。为了更有效地利用未使用的频谱，本提案寻求设计适应快速变化的网络条件的通信系统。将考虑网络中不同层次的合作与竞争。本建议所研究的频谱创新用途，将有助规管机构及服务供应商为公众提供更大的无线互联网接入容量。所提出的研究的战略计划涉及开发分布式多层算法，用于在受全局资源约束的可变容量网络中进行联合介质访问控制和资源分配。将设计共同优化端到端速率和资源分配的协议，以最大限度地提高全网和频谱利用率。具体而言，本提案旨在解决无线网络中的技术问题，如：(1)多址衰落信道；（ii）随机数据包到达和时频分配；实时传输中的能量/延迟权衡；（iv）端到端性能管理。多小波包调制（MWPM）是由申请人最近提出的一种通用的正交频分复用（OFDM）方案，用于适应认知无线电系统。研究将建立在MWPM作为多址方案的基础上，该方案提供了灵活的时间频谱时频平铺。该研究将影响新的无线网络架构的发展方向，并将适用于任何无线电系统，从无线到有线调制解调器，实现自适应调制方案和跨层网络协议设计。

New communications technologies and services have created an explosive demand for electromagnetic spectrum. The radio spectrum is a limited resource, the use of which is licensed by governments. Traditionally, spectrum allocations are based around the paradigm of fixed long-term frequency band assignments and do not necessarily ensure spectrum is being used most efficiently at all times, in all areas. To exploit unused spectrum more efficiently, this proposal seeks to design communication systems that adapt to rapidly changing network conditions. Different levels of cooperation and competition in the network will be considered. Innovative use of spectrum investigated in this proposal will aid regulatory bodies as well as service providers in supplying the public with increased capacity for wireless Internet access. The strategic plan for the proposed research involves the development of distributed, multi-layer algorithms for joint medium access control and resource allocation in networks with variable capacities subject to a global resource constraint. Protocols will be devised that jointly optimize end-to-end rates and resource allocation to maximize total network and spectrum utility. Specifically, this proposal aims to address technical issues in radio networks, such as (i) multi-access fading channels; (ii) random packet arrivals and time-frequency allocations; (iii) energy/delay tradeoff in real-time transmissions; and (iv) end-to-end performance management. The multi-wavelet packet modulation (MWPM), introduced recently by the applicant, generalizes orthogonal frequency division multiplexing (OFDM) schemes proposed for adaptation in cognitive radio systems. The investigations will build on the MWPM as the multiple access scheme which provides flexible time-frequency tiling of the temporal spectrum. The research will impact the direction of the development of new radio network architectures and will be applicable to any radio system, from wireless to cable modems, implementing adaptive modulation schemes and the cross-layer network protocol design.