无线传感器网络可靠数据传输协议的研究

数据的可靠传输是一个成熟的网络应该给用户所提供的基本服务。在能量受限和带宽受限的无线传感器网络(wireless sensor networks)中,同样需要可靠的数据传输。首先分析了TCP应用于无线传感器网络的不足,然后介绍了目前可靠数据传输协议的主要研究进展和关键技术,重点阐述了PSFQ、ESRT和RMST协议的应用场景和基本原理,分析了不同协议各自的优缺点,最后展望了可靠数据传输的研究方向和发展前景。     

无线传感器网络中数据的节能可靠传输

通常来讲无线传感器网络的节能与可靠性是矛盾的,节能与可靠性措施很难统一。该文明确了节能可靠传输面临的主要问题,分析了相关解决策略,总结了无线传感器网络中数据节能可靠传输的方案,说明了无线传感器网络应用场景对传输策略选择的影响,并进一步介绍了三种基于IEEE 802.15.4的网络标准。     

无线传感器网络智能建筑节能系统数据传输协议设计与实现

无线传感器网络智能建筑节能系统主要是通过分布式自组织的无线传感器网络对建筑物中的环境等信息进行感知,动态地对建筑物中的灯光、空调等设备进行控制,实现智能节能的目的。其中,控制信息的可靠传输对智能建筑节能起着关键性的作用。该协议讨论研究了现有的无线传感器网络数据传输技术中的不足,并结合智能建筑节能的特点和实际需求,设计和实现了一个基于优先级队列及优先级ACK的数据传输方案,对重要信息提供端到端的保证,实现了控制信息的及时、可靠传输。     

无线传感器网络中一种双路径可靠路由协议的设计

文章简要介绍了无线传感器网络的特点,分析了洪泛路由算法的不足之处.在此基础上,设计了一种利用节点的级别值的双路径可靠路由协议（Double Parents And Reliable Protocol,简称DPRP）.新协议有效避免了洪泛算法的盲目性和延时长的问题,从而提升了数据传输的实时性和可靠性.仿真结果表明,该协议具有更高的可靠性和实时性.     

适合关键信息可靠传输的节点拥塞避免算法

无线传感器网络节点通信能力有限,有事件发生时,数据产生速率将急剧增大,网络可能会发生拥塞的问题,提出了一种适合关键信息可靠传输的节点拥塞避免算法CAARTKI (Congestion Avoidance Algorithm for Reliable Transmission of Key Information)。算法主要思想是通过引入区分服务,数据包按其重要性不同划分为不同的优先级,高优先级分组优先得到传输。本算法中,节点只有在下一跳节点为其分配了发送窗口才可以发送数据,以避免节点拥塞发生;在链路层考虑拥塞避免的同时,在路由层通过选择可用缓存空间多的邻居节点作为下一跳节点,使关键信息能及时可靠传输到负载较轻的节点,减少由于负载过重时重要信息不能及时传输的可能;在关键信息密集产生时,采用主动丢包策略,丢弃部分低优先级分组,为高优先级分组腾出缓存区间。NS2仿真实验结果表明:CAARTKI可预防拥塞的产生,最高优先级分组的丢包率低,平均网络时延较小,能保证关键信息的及时可靠传输。      

无线传感器网络可靠的传输层协议安全性研究

端到端通信的可靠性是无线传感器网络许多应用场合的重要条件。对无线传感器网络传输层安全机制进行了综合分析,在建立攻击模型的基础上,深入研究了无线传感器网络可靠的传输层协议安全行问题,并具体提出了安全防御方法,为进一步的研究拓展了思路。     

无线传感器网络路由协议

本文在简要地介绍了无线传感器网络体系结构的基础上,研究了当前主要的几种无线传感器网络路由协议模型,并进行了比较分析.     

无线传感器网络MAC协议研究

无线传感器网络因其巨大的应用前景,已成为计算机与通信领域一个活跃的研究分支。随着对无线传感器网络MAC(media access control)层的研究的深入,出现了许多为无线传感器网络设计的具有低能耗特征的MAC协议。对其中的典型协议进行了分析比较,给出了进一步的研究方向。     

基于功率分配的无线传感器网络拥塞控制协议

由于无线传感器网络的资源受限,相比传统网络其传输过程更容易导致丢包和拥塞。为了避免和控制拥塞,本文提出了一种利用功率分配重新选择路径的拥塞控制算法,首先参考路径传输的多种QoS相关参数度量网络的路径代价和节点可用资源的信息,基于测量得到的网络拥塞水平通过传输功率递增和递减选择不同的路径控制网络拥塞。仿真结果表明所提出的协议减少了网络时延,提高了系统吞吐量和网络生命周期。      

无线传感器网络中PECR协议的改进

PECR协议中对下游节点是否拥塞仅仅是一种预测,这种预测有时是不准确的,且在下游节点没有满足条件拥塞度和剩余能量的时候,传输层的问题要回到网络层去处理。为了解决PECR协议中存在的这些问题,文章引入了具有发送优先级的两个队列,优先发送优先级高的数据,在实际出现拥塞时会通知上游节点减少发送速率,并先抛弃掉优先级低的数据。在拥塞严重的时候也会抛弃掉优先级高的数据,但不会再回到网络层去处理问题。     

一种无线传感器网络拥塞控制机制

无线传感器网络的拥塞会增加网络延迟、降低网络吞吐量、尤其不利于传感器网络的节能。该文提出了一种能量有效的无线传感器网络拥塞控制机制,主要包括逐跳拥塞反馈和速率调节两部分。节点周期性地计算其上游节点发送速率和本地缓冲队列可用空间,并根据一定策略来推测在当前周期内发生拥塞的可能性;拥塞节点的上游节点收到拥塞反馈后根据自身缓冲队列的使用情况来降低速率,此拥塞节点同时向其下游节点申请提高发送速率;基站根据应用要求以闭环方式调节源速率。仿真实验表明,该文的拥塞控制机制不仅能有效地缓解网络拥塞,还保持了网络吞吐量的稳定并具有良好的能源有效性。     

A Delay-Aware Congestion Control Protocol for Wireless Sensor Networks

In wireless sensor networks, congestion leads to buffer overflowing, and increases delay. The tradi-tional solutions use rate adjustment to mitigate congestion, thus increasing the delay. A Delay-aware congestion con-trol protocol (DACC) was presented to mitigate congestion and decrease delay. In order to improve the accuracy of the existing congestion detection model which is based on the buffer occupancy of a single node, DACC presents a new model considering both the real-time buffer occupancy and the average transmission time of packets. DACC uses the untapped bits in the IEEE 802.11 Distributed coordination function (DCF) frames header to carry congestion infor-mation. During the congestion alleviation period, DACC presents a channel occupancy mechanism which is based on the real-time buffer occupancy for the purpose of decreas-ing delay and preventing packet loss. Simulation results indicate that in terms of delay, packet delivery ratio, col-lision and buffer load, DACC has comparative advantages than those of 802.11 DCF, Priority-based congestion con-trol protocol (PCCP) and Decoupling congestion control and fairness (DCCF).     

An Energy Conservation MAC Protocol in Wireless Sensor Networks

Wireless sensor networks use battery-operated computing and sensing devices. Because of the limitation of battery power in the sensor nodes, energy conservation is a crucial issue in wireless sensor networks. Consequently, there is much literature presenting energy-efficient MAC protocols based on active/sleep duty cycle mechanisms to conserve energy. Convergecast is a common communication pattern across many sensor network applications featuring data gathering from many different source nodes to a single sink node. This leads to high data collision rates, high energy consumption, and low throughput near the sink node. This paper proposes an efficient slot reservation MAC protocol to reduce energy consumption and to make transmission more efficient in data gathering wireless sensor networks. The simulation results show that our protocol provides high throughput, low delivery latency and low energy consumption compared to other methods.

一种卫星网络中基于Agent的可靠组播传输协议

IP 组播技术是一种可以把单个数据信息同时分发到不同的用户去的网络技术。卫星网络固有的广播信道特性使得它很适合组播应用。然而目前针对卫星网络的可靠组播服务研究很少,虽然已经有一些关于地面Internet组播协议建议,但他们并不适合于卫星网络。在卫星网络组播传输中的一个关键技术是传输协议设计。该文提出一种基于Agent的宽带卫星网络可靠组播传输协议(ASMTP)。该协议利用接收端Agent来实现卫星组播,采用分组级FEC和本地差错恢复纠正传播中的非相关错误和相关错误。在ASMTP中,还实现了流量控制和拥塞控制机制。仿真结果表明,在卫星网络环境中,ASMTP性能优于MFTP(Multicast File Transport Protocol),同时具有较好的网络可扩展性。     

WTCP: A Reliable Transport Protocol for Wireless Wide-Area Networks

Wireless wide-area networks (WWANs) are characterized by very low and variable bandwidths, very high and variable delays, significant non-congestion related losses, asymmetric uplink and downlink channels, and occasional blackouts. Additionally, the majority of the latency in a WWAN connection is incurred over the wireless link. Under such operating conditions, most contemporary wireless TCP algorithms do not perform very well. In this paper, we present WTCP, a reliable transport protocol that addresses rate control and reliability over commercial WWAN networks such as CDPD. WTCP is rate-based, uses only end-to-end mechanisms, performs rate control at the receiver, and uses inter-packet delays as the primary metric for rate control. We have implemented and evaluated WTCP over the CDPD network, and also simulated it in the ns-2 simulator. Our results indicate that WTCP can improve on the performance of comparable algorithms such as TCP-NewReno, TCP-Vegas, and Snoop-TCP by between 20% to 200% for typical operating conditions.     

一种无线传感器网络自适应协同通信路由协议

无线传感器网络的重要应用特性是具有感测信息的传感节点形成一个自适应本地网络,由中心节点执行不同的协作信息处理任务。该文基于互信息量分析了不同中心节点选择机制的开销性能,证明了基于扩散计算的选择机制的开销有效性;提出一种自适应协同通信路由协议(ACCRP)：节点以分布式的方式选择中心节点并建立传输路径;分析讨论了ACCRP的性能参数;并通过实验验证了ACCRP是能源有效的、可扩展的自适应路由协议。     

A Distributed Query Protocol in Wireless Sensor Networks

In wireless sensor networks, query execution over a specific geographical region is an essential function for collecting sensed data. However, sensor nodes deployed in sensor networks have limited battery power. Hence, the minimum number of connected sensor nodes that covers the queried region in a sensor network must be determined. This paper proposes an efficient distributed protocol to find a subset of connected sensor nodes to cover the queried region. Each node determines whether to be a sensing node to sense the queried region according to its priority. The proposed protocol can efficiently construct a subset of connected sensing nodes and respond the query request to the sink node. In addition, the proposed protocol is extended to solve the k-coverage request. Simulation results show that our protocol is more efficient and has a lower communication overhead than the existing protocol.     

一种低时延的无线传感器网络MAC协议

简要分析了无线传感器网络MAC层协议的作用,针对MAC协议在低时延方面的不足,提出了一种低时延的MAC协议(L-MAC).该协议采用汇聚树,在满足低功耗的基础上,减少了时延.理论分析和仿真实验表明L-MAC较好地解决了时延问题.     

Energy-efficient Rate Adaptation MAC Protocol for Ad Hoc Wireless Networks

In this paper, two novel energy-efficient rate adaptation schemes are presented. The proposed protocols use the Distributed Power Control (DPC) algorithm to predict the channel state and determine the necessary transmission power which optimizes the energy consumption. The first proposed rate adaptation scheme heuristically alters the modulation rate to balance the energy-efficiency and the required throughput which is estimated with queue fill ratio. Moreover, the back-off scheme is incorporated to mitigate congestion and reduce packet losses due to buffer overflows thus minimizing energy consumption. Consequently, the nodes will conserve energy when the traffic is low, offer higher throughput when needed and save energy during congestion by limiting transmission rates. The second rate adaptation scheme employs dynamic programming (DP) principle to analytically select modulation rate and a burst size to be used during transmission. The proposed quadratic cost-function minimizes the energy consumption while alleviating network congestions and buffer overflows. The proposed DP solution renders a Riccati equation ultimately providing an optimal rate selection. The simulation results indicate that an increase in throughput by 96% and energy-efficiency by 131% is observed when compared to other available protocols, for example Receiver Based AutoRate (RBAR).