Multi-radio无线网络中基于协议冲突模型的功率分配算法研究

为了提高无线Ad hoc网络中的Multi-radio Multi-channel利用率,最大化全网吞吐量,提出了一种基于协议冲突模型的功率分配算法-LPCA。LPCA首先利用整数线性规划方法得到了最小功率下所有链路并行传送数据所需的最小信道数,然后又分别估计了相同功率和混合功率下Multi-radio Multi-channel网络的吞吐量上界。实验结果表明,LPCA算法能较好的利用多信道资源,有效地提高网络的吞吐量等性能。

基于Multi-Radio Multi-Channel传感器网络无冲突信道分配算法的研究

为降低通信冲突和信道干扰,对Mult-i Radio Mult-i Channel传感器网络无冲突信道进行研究,结果证实在网络通信半径大于3倍的网络最大功率通信半径的前提下,Sensor节点规模满足2倍网络功率级数加1的环境下,网络无冲突信道分配的信道数达到网络信道冲突图的最大值。文章通过对无冲突信道算法的运用,最终证实其可以有效地提高传感器网络的工作效率,大幅度提升网络的吞吐量。

一种通用的Beyond 3G Multi-Radio接入架构

下一代移动通信网(Beyond 3G)是多种无线接入(Multi-Radio)共存的融合网络.如何有效集成异构无线网络,优化使用全部的无线资源是B3G研究领域内关键课题之一.在分析目前多种异构无线网络整合方案的基础上,借鉴欧洲IST 6th框架中Multi-Radio接入架构的基本思想,考虑在链路层实现异构无线网络之间的整合,从而提出一种通用B3G Multi-Radio接入架构模型,该模型可以无缝融合多种无线接入技术、有效利用全网无线资源.

Multi-Power Multi-Radio传感器网络跨层优化的路由方法研究

针对Multi-Power Multi-Radio无线传感器网络的特性,研究了跨层优化的最小传输时延路由问题,利用线性规划方程设计了该问题的最优问题模型,并设计了有效的多项式时间解决方案.实验结果表明,提出的联合优化的路由方案能有效地减小端到端的传输时延.

Multi-Radio传感器网络MAC协议可靠性的研究

研究了Multi-Radio传感器网络MAC协议的可靠性问题,建立Multi-Radio传感器网络MAC协议可靠性的概率模型,并分了协议的可靠性,同时比较了Multi-Radio传感器网络与现有传感器网络的差别。实验结果表明,对MAC协议可靠性的分析与实验结果相一致,从而验证了本理论分析的正确性。

Multi-Radio无线Ad Hoc网络中基于协议冲突模型的功率分配方案研究

为了提高无线Ad Hoc网络中的Multi-Radio Multi-Channel利用率,最大化全网吞吐量,提出了一种基于协议冲突模型的功率分配算法———LPCA.LPCA首先利用整数线性规划方法得到了最小功率下所有链路并行传送数据所需的最小信道数.然后又分别估计了相同功率和混合功率下Multi-Radio Multi-Channel网络的吞吐量上界.实验结果表明,LPCA算法能较好地利用多信道资源,有效地提高网络的吞吐量等性能.

Joint channel assignment and cross-layer routing protocol for multi-radio multi-channel Ad Hoc networks

To study multi-radio multi-channel （MR-MC） Ad Hoc networks based on 802.11, an efficient cross-layer routing protocol with the function of joint channel assignment, called joint channel assignment and cross-layer routing （JCACR）, is presented. Firstly, this paper introduces a new concept called channel utilization percentage （CUP）, which is for measuring the contention level of different channels in a node’s neighborhood, and deduces its optimal value for determining whether a channel is overloaded or not. Then, a metric parameter named channel selection metric （CSM） is designed, which actually reffects not only the channel status but also corresponding node’s capacity to seize it. JCACR evaluates channel assignment by CSM, performs a local optimization by assigning each node a channel with the smaller CSM value, and changes the working channel dynamically when the channel is overloaded. Therefore, the network load balancing can be achieved. In addition, simulation shows that, when compared with the protocol of weighted cumulative expected transfer time （WCETT）, the new protocol can improve the network throughput and reduce the end-to-end average delay with fewer overheads.

Intelligent Network Selection for Data Offloading in 5G Multi-Radio Heterogeneous Networks

In next generation networks, multiradio networks are emerging in order to deal with exponential data traffic increasing. Integrated Femto-WiFi(IFW) small cells have been introduced by 3GPP to offload data from cellular networks recently. These IFW cells are multi-mode capable(i.e., both licensed bands via cellular interface and unlicensed bands via WiFi interface). Therefore how to offload data effectively has become one of the most significant discussions in 5G Multi-Radio Heterogeneous Network. So far, most researches mainly focus on the generality of UEs, few attention has been paid to UEs' individual requirements. Considering UE's preference vary from individual to individual, in this paper, we present an UE preference-aware network selection scheme for mobile data offloading. It intelligently supports the distribution of heterogeneous classes of services, considers different types of UEs and delay-tolerant flows, and handles the mobility of UEs. The simulation results show the superiority of the proposed algorithm in user fairness, enhanced capacity and energy saving maximization.

Centralized Quasi-Static Channel Assignment for Multi-Radio Multi-Channel Wireless Mesh Networks

Employing multiple channels in wireless multihop networks is regarded as an effective approach to increas-ing network capacity. This paper presents a centralized quasi-static channel assignment for multi-radio multi-channel Wireless Mesh Networks (WMNs). The proposed channel assignment can efficiently utilize multiple channels with only 2 radios equipped on each mesh router. In the scheme, the network end-to-end traffics are first modeled by probing data at wireless access points, and then the traffic load between each pair of neighboring routers is further estimated using an interference-aware estimation algorithm. Having knowledge of the expected link load, the scheme assigns channels to each radio with the objective of mini-mizing network interference, which as a result greatly improves network capacity. The performance evalua-tion shows that the proposed scheme is highly responsive to varying traffic conditions, and the network per-formance under the channel assignment significantly outperforms the single-radio IEEE 802.11 network as well as the 2-radio WMN with static 2 channels.

Multi-Radio Cooperation Technology and Heterogeneous Network Convergence

The heterogeneous network convergence is the trend of future network development. However, many bottlenecks exist in the converged system such as high time delay, high energy consumption, and low data rate. Multi-Radio Cooperation (MRC) technology is specially designed to overcome these bottlenecks and to satisfy the requirements of heterogeneous network convergence. MRC can improve network capacity, reduce the energy consumption of radio devices, and decrease handover latency between heterogeneous networks by the cooperation of multiple radios, and by efficient management and feasible allocation of multi-radio resources. MRC makes real seamless heterogeneous network convergence possible.

A ROUTING PROTOCOL BASED ON INTERFERENCE-AWARE AND CHANNEL-LOAD IN MULTI-RADIO MULTI-CHANNEL AD HOC NETWORKS

Improving capacity and reducing delay are the most challenging topics in wireless ad hoc networks. Nodes that equip multiple radios working on different channels simultaneously permit ef-fective utility of frequency spectrum and can also reduce interference. In this paper, after analyzing several current protocols in Multi-Radio Multi-Channel (MR-MC) ad hoc networks, a new multi-channel routing metric called Integrative Route Metric (IRM) is designed. It takes channel load, inter-flow, and intra-flow interference into consideration. In addition, an MR-MC routing protocol based on Interference-Aware and Channel-Load (MR-IACL) is also presented. The MR-IACL can assign channels and routings for nodes according to channel load and interference degree of links, and optimize channel distribution dynamically to satisfy the features of topology changing and traffic frequent fluctuation during network running. The simulation results show that the new protocol outperforms others in terms of network throughput, end-to-end delay, routing overhead, and network lifetime.

Multi-Radio无线传感器网络中基于缓存和信道切换的数据查询算法的研究

针对Multi-Radio Multi-Channel传感器网络中链路服务质量和信道冲突等问题,提出并证明了基于缓存和信道切换的数据查询问题是一个NP完全问题.根据数据流守恒和链路-信道等约束条件,建立线性规划方程,得到该问题的最优解模型,并提出了一个多项式时间的近似算法——贪心新覆盖数据算法.该算法采用动态规划策略最小化缓存节点将单位数据包传输到查询节点所需要的路径时延,再贪心选择其具有最小路径时延的缓存节点,收集其新覆盖数据.理论分析和实验结果表明,提出的方案能有效地减少数据收集时延,提高数据查询效率.

Multi-power multi-radio传感网中联合调度、信道和功率分配的最优路由策略

研究了multi-power multi-radio无线传感器网络中联合调度、信道和功率分配的最优路由问题,并利用线性规划方程设计了该问题的最优路由方案,同时联合解决了链路调度、信道和功率分配问题.然后针对最优路由问题的NP复杂性,设计了有效的多项式时间解决方案.实验结果表明,提出的联合优化的路由方案能有效地减小端到端的传输时延和能量消耗.

Network selection policy in multi-radio access environment using stochastic control theory

Network selection is crucial in improving the performance of heterogeneous wireless access systems. Most of previous work on network selection or radio resource allocation concentrates on the capability of each available network and ignores the time-varying nature of wireless media due to channel fading. However, the channel condition determines the state of each wireless network and plays a vital role in ensuring quality of service in multi-radio access environment. In this article, we propose a network selection policy using stochastic control theory considering the time-varying and stochastic character of wireless channels. The proposed scheme selects one network among different alternatives in each decision epoch according to the channel state of each network, which is modeled as finite-state Markov channel, with the objectives of increasing the data-rate, decreasing the bit error rate and minishing the delay. The procedure of network selection is formulated as a stochastic control problem, which can be solved using linear programming and primal-dual index heuristic algorithm. Simulation results are presented to show that network selection has great impact on the system performance, and the proposed scheme can improve the performance significantly.

Fairness-oriented routing algorithm joint with power control and channel assignment for multi-radio multi-channel wireless mesh networks

The multi-radio multi-channel wireless mesh network （MRMC-WMN） draws general attention because of its excellent throughput performance, robustness and relative low cost. The closed interactions among power control （PC）, channel assignment （CA） and routing is contributed to the performance of multi-radio multi-channel wireless mesh networks （MRMC-WMNs）. However, the joint PC, CA and routing （JPCR） design, desired to achieve a global optimization, was poor addressed. The authors present a routing algorithm joint with PC and CA （JPCRA） to seek the routing, power and channel scheme for each flow, which can improve the fairness performance. Firstly, considering available channels and power levels, the routing metric, called minimum flow rate, is designed based on the physical interference and Shannon channel models. The JPCRA is presented based on the genetic algorithm （GA） with simulated annealing to maximize the minimum flow rate, an non-deterministic polynomial-time hard （NP-Hard） problem. Simulations show the JPCRA obtains better fairness among different flows and higher network throughput.

Maximizing Networking Capacity in Multi-Channel Multi-Radio Wireless Networks

Providing each node with one or more multi-channel radios offers a promising avenue for enhancing the network capacity by simultaneously exploiting multiple non-overlapping channels through different radio interfaces and mitigating interferences through proper channel assignment. However, it is quite challenging to effectively utilize multiple channels and/or multiple radios to maximize throughput capacity. The National Natural Science Foundation of China（NSFC） Project61128005 conducted comprehensive algorithmic-theoretic and queuing-theoretic studies of maximizing wireless networking capacity in multi-channel multi-radio（MC-MR） wireless networks under the protocol interference model and fundamentally advanced the state of the art. In addition, under the notoriously hard physical interference model, this project has taken initial algorithmic studies on maximizing the network capacity, with or without power control. We expect the new techniques and tools developed in this project will have wide applications in capacity planning, resource allocation and sharing, and protocol design for wireless networks, and will serve as the basis for future algorithm developments in wireless networks with advanced features, such as multi-input multi-output（MIMO） wireless networks.

Channel Aware Opportunistic Routing in Multi-Radio Multi-Channel Wireless Mesh Networks

Opportunistic routing （OR） involves multiple candidate forwarders to relay packets by taking advantage of the broadcast nature and multi-user diversity of the wireless medium. Compared with traditional routing （TR）, OR is more suitable for the unreliable wireless link, and can evidently improve the end to end throughput. At present, there are many achievements concerning OR in the single radio wireless network. However, the study of OR in multi-radio wireless network stays the beginning stage. To demonstrate the benefit of OR in multi-radio multi-channel network, we propose a new route metric -- multi-channel expected anypath transmission time （MEATT）, which exploits the channel diversity and resource of multiple candidate forwarders for OR. Based on the new metric, a distributed Mgorithm named Channel Aware Opportunistic Routing （CAOR） is proposed. The simulation results demonstrate that MEATT improves 1.14 and 1.53 times of the average throughput than existing expected anypath transmission time （EATT）and metric of interference and channel switching cost （MIC） respectively. The average delay of MEATT is 17% and 40% lower than those of EATT, MIC, respectively.

EMSC:a joint multicast routing,scheduling,and call admission control in multi-radio multi-channel WMNs

This paper deals with the problem of joint multicast routing,scheduling,and call admission control in multiradio multi-channel wireless mesh networks.To heuristically solve this problem,we propose a cross-layer algorithm named“extended MIMCR with scheduling and call admission control phases(EMSC)”.Our model relies on the on-demand quality of service(QoS)multicast sessions,where each admitted session creates a unique tree with a required bandwidth.The proposed scheme extends the MIMCR algorithm to fairly schedule multiple non-interfering transmissions in the same time slot.It also exploits a call admission control mechanism to protect the QoS requirements of the multicast traffics.EMSC reduces the number of occupied time slots,with consideration of spatial reuse,both Intra-flow and Inter-flow interferences,and selecting the minimum-interference minimum-cost paths.This subsequently leads to better radio resource utilization and increases the network throughput.Simulation results show that the proposed algorithm outperforms the other algorithms and improves the network performance.

射频隐身仿真分析和评估研究

当前对飞行器平台射频隐身的重视度越来越高,为了贴合实际地分析评估射频隐身性能,提出了一种用于多机协同传感器信号级联合仿真的评估方法。结合射频特征、低被截获性能表征指标以及作战场景、飞行器平台、雷达模型、截获接收机模型和低被截获性能分析算法模型,构建了可以用来对多机协同等作战样式下的射频隐身性能进行分析评估的仿真系统,为射频隐身设计提供支撑依据与评估验证环境。针对信息量大、复杂度高的表征参量计算模型,研究其近似快速算法,提高仿真系统的实用性。

空间信息网的Ka频段非正交多址接入中继系统

针对深空通信的系统信息传输效率低,时延长的问题,文中设计一种空间信息网的Ka频段非正交多址接入中继系统,推导出中继卫星配备单天线情况下的中断概率和遍历系统容量等关键指标的解析表达式,提出的非正交多址接入中继系统在节约一半传输时间条件下,达到与正交多址接入系统相同遍历系统容量时所需的功率分配方案。通过仿真,验证了该方案的可行性。