适用于水声传感网络的多链路传输MAC协议

针对水声传感网络存在的高时延、低信道利用率等问题,提出一种新的多链路传输介质访问控制协议.该协议节点通过RTS/CTS握手协议交互时延信息和传输计划,实现多条链路传输数据.在汇聚节点接收多个节点的数据时,汇聚节点根据节点的时延和接收的数据帧大小规划节点之间的发送顺序,避免传输冲突造成的能量损失和低信道利用率,同时为得到...     

基于进化博弈论的水声传感器网络介质访问控制协议

为降低水声传感器网络低带宽、高延迟的特性对介质访问控制(MAC)层性能的影响,提出一种基于进化博弈论的MAC协议。该协议中,每个传感器节点可以采用空间复用和时间复用两种策略,并利用复制动力学方程得到进化稳定策略,达到进化稳定均衡,提高信道利用率和数据传输效率,进而实现MAC协议的性能优化。仿真实验结果表明,与传统的水声传感器网络MAC协议相比,基于进化博弈论的MAC协议可以提高网络吞吐量以及数据包发送成功率。     

一种基于接收节点控制的无线传感器网络媒体访问控制协议

为了提高无线传感器网络数据包传输效率,提出一种基于时间同步、接收节点控制的无线传感器网络媒体访问控制协议。该协议在保持节点低功耗工作的前提下,使父节点在一个操作周期内,通过多次邀请机制和迸发传输机制,能够与多子节点进行数据包的多次传输。该多次邀请机制,使父节点具备了在单个操作周期内,从多个子节点接收数据包的能力,本质上减少了子节点之间的竞争、提高了信道利用率,增强了父节点对数据包传输的控制力。迸发传输机制,使得父节点可以在一次通讯中连续接收多个数据包,进一步提高了信道的利用率。仿真结果表明:当网络载荷强度增大时,该协议使网络中的节点能够充分利用信道,显著提高了网络中数据包的传输效率,随着网络载荷增加,使网络吞吐量增大近50%。     

接收方预约信道的水声传感器网络MAC协议

为了获得更高的网络吞吐量,更低的端到端时延,设计出了一种适用于分簇网络的水声传感器网络MAC协议,该协议采用接收方建立握手机制,有效的获取邻居节点通信时的状态,动态分配发送时隙,实现数据包以报文序列方式无冲突的到达接收端.仿真结果表明,与同类MAC协议(FERI, RIPT)相比,该协议提高了网络吞吐量,降低了数据丢失率和端到端时延.     

预调度流水线方式的水声传感器网络MAC协议

针对水声传感器网络中MACAW协议存在的延时问题,在传统USENIX握手协议的基础上,提出一种新的水声传感器网络媒体接入控制(MAC)协议。使用节点预调度方法对数据的传输时隙采取预约选择,在上上级节点与上级节点进行请求发送(RTS)/允许发送(CTS)握手与数据传输的同时,下级节点复用上级节点发送的CTS和数据信号作为发送给自己的RTS和确定发送信号,形成一种预调度流水线形式的M AC协议。仿真结果表明,该协议与传统的MACAW协议相比,能有效降低节点间的传输延时,提高水声传感器网络吞吐量,并且有效缓解碰撞,节约能源。     

非饱和状态下时隙CSMA/CA机制改进与性能分析

针对无线传感器网络中有重要信息的高优先级数据包需要尽快传输,且IEEE 802.15.4协议本身不支持任何优先级机制的情况,结合优先级调度策略和差分服务机制,对具有优先级级的时隙CSMA/CA机制进行全面数学建模,包括节点马尔科夫模型和信道马尔科夫模型,据此提出了一种非饱和状态下具有优先级的IEEE 802.15.4时隙CSMA/CA机制性能的分析方法。通过比较分析,改进的机制对提高网络中高优先级数据包的传输性能具有积极作用。     

水声通信网络设计与OPNET平台下仿真

水声通信网络是当代海洋研究、海洋资源勘探和开发、海洋环境立体监测、地震海啸监测和战术监测等水下系统无线信息传输的主要手段,但其性能受水声信道特性影响严重。采用OPNET对水声通信网络节点模型与分层协议进行设计与实现,包括基于MC-CDMA的多用户检测以及基本CSMA/CA机制的信道握手流程与网络分配向量（NAV）帧冲突处理机制等。同时建立并测试了一个包含1个主节点与4个传感器节点的水声通信网络,仿真结果表明设计的水声通信网络能够更好的克服冲突,减少数据包重发,从而获得更高水声通信网络的吞吐量,减少端对端传输延时与能量消耗。     

基于可变长时隙机制的水下传感器网络MAC协议

通过研究水声通信的特点,分析水下物体的运动特性,提出了一种基于可变长时隙机制的水下传感器网络MAC协议。新协议中,传感器节点会周期性获取邻居节点的位置信息,并根据节点间相互距离的变化自适应地调整信道预约时隙长度,当节点由于运动引起网络区域收缩,节点之间距离变小时,预约时隙长度变小,反之,时隙长度增大。可变长时隙机制,提高了信道时隙资源的利用率。仿真结果表明,动态环境下新协议相对现有的协议在有效网络吞吐量性能上提升15%左右。     

多跳无线传感器网络的高能效数据收集协议

提出了一种集基于节点地理位置信息的集成拓扑控制、MAC和路由为一体的高能效数据收集协议REEGF(geographic forwarding protocol with reliable and energy-efficient).REEGF使用了具有双无线信道协作通信结构的网络节点,以利用唤醒信道发送和侦听忙音减少节点的空闲侦听时间.利用无线传感器网络的时间同步算法和依赖于本地节点密度、节点剩余能量的概率同步调度算法,REEGF使处于监测状态的网络节点以概率在每个网络侦听周期同步唤醒,减少冗余节点的空闲     

基于网络效用最大化与冲突避免的无线传感器网络MAC协议

针对周期汇报型无线传感器网络(WSN)中的无线信号冲突和能量利用效率问题,提出了一种基于网络效用最大化与冲突避免的媒体访问控制(UM-MAC)协议。该协议基于时分多路复用(TDMA)调度机制,将效用模型引入无冲突的节点工作时隙分配过程中,把链路可靠性、网络能耗归纳到一个统一的效用优化框架中;进而提出了一个启发式算法,使网络能够快速找到一个基于网络效用最大化与冲突避免的节点工作时隙调度方案。将UM-MAC协议与S-MAC协议和冲突避免MAC(CA-MAC)协议进行比较,在不同节点数量的网络环境中,UM-MAC获得的网络效用较大,平均数据包成功发送率较高,生命周期介于S-MAC与CA-MAC之间,在不同的网络负载下所有节点发数据包到汇聚节点的平均时延有所增加。仿真实验结果表明:UM-MAC协议较好地解决了冲突干扰问题,提高了网络的数据包成功发送率和能量利用效率等性能;在低网络负载时,TDMA类协议的性能并不比竞争类协议好。     

节能感知的无线传感网接入控制与路由优化策略

为降低能耗,延长输电线路监测网络传感器寿命,提出一种新的媒体接入控制与路由联合优化策略。构建无线传感网通信框架,并基于该框架给出一种自适应的簇内调度策略,旨在减少传感器节点的空闲监听,从而降低节点能耗。给出一种按需路由协议,在确保能量等级和信道质量的同时在簇间进行最佳路由选择,基于簇头剩余能量及其到基站的距离,利用非均匀簇技术平衡节点能量分布,延长网络寿命,并构建能耗和延迟模型进行性能评估。实验结果表明,该方案在节能的同时能够显著降低数据传输时延。     

水声传感器网络中基于相关性感知的路由协议

针对水声传感器网络数据传输效率低、能量消耗大的问题,提出一种基于相关性感知的路由协议。该协议根据路由过程中数据的相关性进行数据融合以减少通信量。通过平衡各节点的能量消耗,避免某些节点过早地耗尽能量而影响整个网络的生命周期。仿真结果表明,该路由协议可以在提高数据包传送率的同时,有效降低网络能量消耗。     

链路服务质量限制下多输入多输出媒体接入控制的建模与分析

针对SCMA协议没有同时考虑链路服务质量(QoS)和多输入多输出(MIMO)流的信道接入调度策略的不足,提出一种SCMA/QA协议。协议充分考虑了每个链路中不同流的信道状态,建立了一个基于流的信道状态离散马尔可夫链模型,并融合考虑了每条链路的QoS需求,采用修改的RTS/CTS进行链路QoS的信息交换,通过链路QoS权重作为链路选择的主要因素,将MIMO下基于QoS的链路调度问题建模为一个最优化问题,并在卡罗需-库恩-塔克(KKT)条件下得到最优链路以及通信的流数目。最后,以吞吐量为QoS指标进行了数值分析,结果表明在相同网络环境下,SCMA/QA比SCMA和QCSCMA能更好地提高系统的吞吐量。     

Node scheduling problem in underwater acoustic sensor network using genetic algorithm

Underwater acoustic sensor network (UWASN) has recently aroused the interest of researchers and scientists in this field. The acoustic sensor bandwidth is limited in underwater and it causes low successful packet transmission. One of the methods to overcome this handicap is efficient broadcast scheduling of underwater acoustic sensor node (UASN) that would help in transmitting and receiving data without any collision. This can be done with the help of time division multiple access (TDMA). The basic idea is to address broadcast scheduling problem in UWASN for utilizing the limited available bandwidth by parallelizing the node transmission such that it does not interfere with each other in same time slot; it also minimizes the node turnaround transmission time in the network by optimizing the time slots in TDMA frame. The objective of this paper is to maximize the utilization of the available underwater acoustic bandwidth and to achieve high throughput as well as to reduce the node turnaround wait time by using an evolutionary genetic algorithm (GA). The simulation results prove that every node in the UWASN transmits in an average minimal turnaround time by minimizing the time slots and maximizing the throughput in the network by scheduling the possible nodes with parallel transmission.     

A novel channel-adaptive uplink access control protocol for nomadic computing

We consider the uplink access control problem in a mobile nomadic computing system, which is based on a cellular phone network in that a user can use the mobile device to transmit voice or file data. This resource management problem is important because an efficient solution to uplink access control is critical for supporting a large user population with a reasonable level of quality of service (QoS). While there are a number of recently proposed protocols for uplink access control, these protocols possess a common drawback in that they do not adapt well to the burst error properties, which are inevitable in using wireless communication channels. We propose a novel TDMA-based uplink access protocol, which employs a channel state dependent allocation strategy. Our protocol is motivated by two observations: (1) when channel state is bad, the throughput is low due to the large amount of FEC (forward error correction) or excessive ARQ (automatic repeated request) that is needed and (2) because of item 1, much of the mobile device's energy is wasted. The proposed protocol works closely with the underlying physical layer in that, through observing the channel state information (CSI) of each mobile device, the MAC protocol first segregates a set of users with good CSI from requests gathered in the request contention phase of an uplink frame. The protocol then judiciously allocates channel bandwidth to contending users based on their channel conditions. Simulation results indicate that the proposed protocol considerably outperforms five state-of-the-art protocols in terms of packet loss, delay, and throughput.     

Maximizing multiuser diversity gains in IEEE 802.11 WLANs

Opportunistic scheduling monitors the receivers’ channel states and schedules packets to the receivers in relatively good channel conditions. Opportunistic scheduling can be easily implemented in cellular network systems that have embedded channel state report functions. To apply opportunistic scheduling to wireless LANs, deficient of channel report functions, we first devise an efficient channel probing mechanism. Prior opportunistic scheduling methods for WLANs limit the number of probed receivers and may not fully utilize the potential multiuser diversity gains. In this paper, we develop a new opportunistic scheduling scheme called WDOS (WLAN Distributed Opportunistic Scheduling). WDOS invites all receivers to channel probing and has a potential to fully realize the multiuser diversity gains. To reduce the overhead of probing all active receivers, we devise a contention based RTS/CTS exchange with early termination. A sender initiates channel probing by multicasting an MRTS (modified RTS) frame and each receiver responds with a CTS frame after a backoff delay. Hearing the first CTS frame, the sender terminates channel probing and transmits data frames to the first responder. WDOS attains the multiuser diversity gains by allocating a shorter backoff delay to a receiver in better relative channel conditions. We evaluate the performance of WDOS both via an analytic method and computer simulations. Our performance study shows that WDOS achieves the performance near optimal.     

一种多信道混合方式的无线传感器网络MAC协议

为了提高无线传感器网络的吞吐量,降低时延,本文设计了一种多信道MAC协议——MCHMAC。它采用调度和竞争访问机制相结的混合方式来传输信息,通过动态调整节点的活跃与睡眠状态的时长来节省能量。MCHMAC使用信道状态估计算法对信道进行评估,利用信道调度表来为节点调度状态最优的信道。仿真实验结果证明,本协议提高了吞吐量,降低了网络时延。     

A new medium access control protocol based on perceived data reliability and spatial correlation in wireless sensor network

It is well known that the data of large-scale and dense wireless sensor network has high spatial correlativity. According to the monitoring of a particular event, a new medium access control (MAC) protocol based on perceived data reliability and spatial correlation is proposed in this paper. In this protocol, a ring-shaped space correlation model is established. The nodes close to information source is attributed them high priority in access channel so as to make sure the high quality data send successfully to the sink node and increase the data transferring efficiency. The new protocol can make the received data reflect the real physical phenomenon. At the same time, it can make the data transmission of the nodes far to information source be brought down and the amount of required data nodes be reduced. So the new protocol can prolong lifetime of the whole network. Our simulation results show that the new MAC protocol can supply better network service under low energy consumption and transmission delay. This is very useful for all kinds of mobile services of Internet of Things.     

基于广播机制的多方量子远程制备协议

量子态远程制备(RSP)是量子信息过程的一个重要分支。为了解决一个发送者向多个接收者同时制备相同量子态的问题,提出了基于广播机制的1对2三方量子态远程制备协议,并将其拓展到1对N多方量子态远程制备中。该协议使用GHZ态作为量子信道,通过构造两组特殊测量基,发送方进行两次多粒子投影测量,接收方根据测量结果进行幺正操作,最终实现1个发送者向多个接收者同时制备相同的粒子态。经分析,协议的这种广播制备模式可以适用于任意多个接收者的情形。