Network Coding is a relatively new forwarding paradigm where intermediate nodes perform a store, code, and forward operation on incoming packets. Traditional forwarding approaches, which employed a store and forward o...Network Coding is a relatively new forwarding paradigm where intermediate nodes perform a store, code, and forward operation on incoming packets. Traditional forwarding approaches, which employed a store and forward operation, have not been able to approach the limit of the max-flow min-cut throughput wherein sources transmitting information over bottleneck links have to compete for access to these links. With Network Coding, multiple sources are now able to transmit packets over bottleneck links simultaneously, achieving the max-flow min-cut through-put and increasing network capacity. While the majority of the contemporary literature has focused on the performance of Network Coding from a capacity perspective, the aim of this research has taken a new direction focusing on two Quality of Service metrics, e.g., Packet Delivery Ratio (PDR) and Latency, in conjunction with Network Coding protocols in Mobile Ad Hoc Networks (MANETs). Simulations are performed on static and mobile environments to determine a Quality of Service baseline comparison between Network Coding protocols and traditional ad hoc routing protocols. The results show that the Random Linear Network Coding protocol has the lowest Latency and Dynamic Source Routing protocol has the highest PDR in the static scenarios, and show that the Random Linear Network Coding protocol has the best cumulative performance for both PDR and Latency in the mobile scenarios.展开更多
QoS supported MAC mechanism is a key issue for supporting QoS in wireless ad hoc networks. A new backoff algorithm, named RWBO＋BEB, was proposed previ- ously to decrease the packet collision probability significantly...QoS supported MAC mechanism is a key issue for supporting QoS in wireless ad hoc networks. A new backoff algorithm, named RWBO＋BEB, was proposed previ- ously to decrease the packet collision probability significantly. In this paper, it is explored how to make RWBO＋BEB support service differentiation in wireless ad hoc networks, and a novel proportional service differentiation algorithm, named p-RWBO, is proposed to allocate the wireless bandwidth according to the band- width ratio of each station. In p-RWBO, station n＇s walking probability （Pw,n） is selected according to its allocated bandwidth ratio. An analytical model is proposed to analyze how to choose Pw, n according to the bandwidth ratios of station n. The simulation results indicate that p-RWBO can differentiate services in terms of both bandwidth and delay.展开更多
在分析当前Ad Hoc网络多信道MAC协议的基础上,提出了一个衡量信道质量的度量参数CQ(Channel Quality)作为信道选择的依据。并提出了一个基于接收方信道质量的多信道MAC协议MMCQ(Multi-channel MAC protocol with Channel Quali-ty of re...在分析当前Ad Hoc网络多信道MAC协议的基础上,提出了一个衡量信道质量的度量参数CQ(Channel Quality)作为信道选择的依据。并提出了一个基于接收方信道质量的多信道MAC协议MMCQ(Multi-channel MAC protocol with Channel Quali-ty of receiver),以解决多信道MAC协议常见的控制信道瓶颈和信道分配公平性问题。仿真表明:该协议在降低控制信道开销的前提下,能显著增加网络的平均吞吐量,并降低端到端平均时延。展开更多
Existing multi-channel Medium Access Control (MAC) protocols have been demonstrated to significantly increase wireless network performance compared to single channel MAC protocols. Traditionally, the channelization st...Existing multi-channel Medium Access Control (MAC) protocols have been demonstrated to significantly increase wireless network performance compared to single channel MAC protocols. Traditionally, the channelization structure in IEEE 802.11 based wireless networks is pre-configured, and the entire available spectrum is divided into subchannels and equal channel widths. In contrast, this paper presents a Traffic-Aware Channelization MAC (TAC-MAC) protocol for wireless ad hoc networks, where each node is equipped with a single half duplex transceiver. TAC-MAC works in a distributed, fine-grai-ned manner, which dynamically divides variable-width subchannels and allocates subchannel width based on the Orthogonal Frequency Division Multiplexing (OFDM) technique according to the traffic demands of nodes. Simulations show that the TAC-MAC can significantly improve network throughput and reduce packet delay compared with both fixed-width multi-channel MAC and single channel 802.11 protocols, which illustrates a new paradigm for high-efficient multi-channel MAC design in wireless ad hoc networks.展开更多
众所周知,无线系统是带宽受限系统,信道分配算法至关重要。本文研究了 Ad hoc 网络的 MAC 层协议,通过对无线令牌环协议 WTRP 进行改进,提出了一种新的具有 QoS 保障的无竞争的分布式并行 MAC 协议,即基于动态优先级的缓冲区状态控制协...众所周知,无线系统是带宽受限系统,信道分配算法至关重要。本文研究了 Ad hoc 网络的 MAC 层协议,通过对无线令牌环协议 WTRP 进行改进,提出了一种新的具有 QoS 保障的无竞争的分布式并行 MAC 协议,即基于动态优先级的缓冲区状态控制协议(DP-BSCP)。仿真结果分析表明,该协议的平均排队等待延迟和平均等待队列长度均比 WTRP 有很大降低;对不同优先级的数据包均有良好的适应性,满足不同优先级的性能需求。从而使系统的稳定性大大增强,更加适用于多业务的综合服务系统。展开更多
文摘Network Coding is a relatively new forwarding paradigm where intermediate nodes perform a store, code, and forward operation on incoming packets. Traditional forwarding approaches, which employed a store and forward operation, have not been able to approach the limit of the max-flow min-cut throughput wherein sources transmitting information over bottleneck links have to compete for access to these links. With Network Coding, multiple sources are now able to transmit packets over bottleneck links simultaneously, achieving the max-flow min-cut through-put and increasing network capacity. While the majority of the contemporary literature has focused on the performance of Network Coding from a capacity perspective, the aim of this research has taken a new direction focusing on two Quality of Service metrics, e.g., Packet Delivery Ratio (PDR) and Latency, in conjunction with Network Coding protocols in Mobile Ad Hoc Networks (MANETs). Simulations are performed on static and mobile environments to determine a Quality of Service baseline comparison between Network Coding protocols and traditional ad hoc routing protocols. The results show that the Random Linear Network Coding protocol has the lowest Latency and Dynamic Source Routing protocol has the highest PDR in the static scenarios, and show that the Random Linear Network Coding protocol has the best cumulative performance for both PDR and Latency in the mobile scenarios.
基金Supported by the National Key Basic Research Program (Grant No. 2007CB310706)the National Science Fund for Distinguished Young Schol- ars (Grant No. 60725102)+2 种基金the National Natural Science Foundation of China (Grant No. 60702055, 60672045)the National High Technology Research and Development Program of China (Grant No. 2007AA01Z246, 2007AA01Z227)Research Fund for the Doctoral Program of Higher Education (Grant No. 20060614018),and Program for New Century Excellent Talents in University
文摘QoS supported MAC mechanism is a key issue for supporting QoS in wireless ad hoc networks. A new backoff algorithm, named RWBO＋BEB, was proposed previ- ously to decrease the packet collision probability significantly. In this paper, it is explored how to make RWBO＋BEB support service differentiation in wireless ad hoc networks, and a novel proportional service differentiation algorithm, named p-RWBO, is proposed to allocate the wireless bandwidth according to the band- width ratio of each station. In p-RWBO, station n＇s walking probability （Pw,n） is selected according to its allocated bandwidth ratio. An analytical model is proposed to analyze how to choose Pw, n according to the bandwidth ratios of station n. The simulation results indicate that p-RWBO can differentiate services in terms of both bandwidth and delay.
文摘在分析当前Ad Hoc网络多信道MAC协议的基础上,提出了一个衡量信道质量的度量参数CQ(Channel Quality)作为信道选择的依据。并提出了一个基于接收方信道质量的多信道MAC协议MMCQ(Multi-channel MAC protocol with Channel Quali-ty of receiver),以解决多信道MAC协议常见的控制信道瓶颈和信道分配公平性问题。仿真表明:该协议在降低控制信道开销的前提下,能显著增加网络的平均吞吐量,并降低端到端平均时延。
基金supported by the National Natural Science Foundation of China under Grant No. 61002032the Doctoral Fund of Ministry of Education of China under Grant No. 20094307110004
文摘Existing multi-channel Medium Access Control (MAC) protocols have been demonstrated to significantly increase wireless network performance compared to single channel MAC protocols. Traditionally, the channelization structure in IEEE 802.11 based wireless networks is pre-configured, and the entire available spectrum is divided into subchannels and equal channel widths. In contrast, this paper presents a Traffic-Aware Channelization MAC (TAC-MAC) protocol for wireless ad hoc networks, where each node is equipped with a single half duplex transceiver. TAC-MAC works in a distributed, fine-grai-ned manner, which dynamically divides variable-width subchannels and allocates subchannel width based on the Orthogonal Frequency Division Multiplexing (OFDM) technique according to the traffic demands of nodes. Simulations show that the TAC-MAC can significantly improve network throughput and reduce packet delay compared with both fixed-width multi-channel MAC and single channel 802.11 protocols, which illustrates a new paradigm for high-efficient multi-channel MAC design in wireless ad hoc networks.
文摘众所周知,无线系统是带宽受限系统,信道分配算法至关重要。本文研究了 Ad hoc 网络的 MAC 层协议,通过对无线令牌环协议 WTRP 进行改进,提出了一种新的具有 QoS 保障的无竞争的分布式并行 MAC 协议,即基于动态优先级的缓冲区状态控制协议(DP-BSCP)。仿真结果分析表明,该协议的平均排队等待延迟和平均等待队列长度均比 WTRP 有很大降低;对不同优先级的数据包均有良好的适应性,满足不同优先级的性能需求。从而使系统的稳定性大大增强,更加适用于多业务的综合服务系统。
