A distributed on-demand bandwidth-constrained multicast routing protocol for wireless ad hoc networks

To meet the bandwidth requirement for the multicasting data flow in ad hoc networks, a distributed on- demand bandwidth-constrained multicast routing （BCMR） protocol for wireless ad hoc networks is proposed. With this protocol, the resource reservation table of each node will record the bandwidth requirements of data flows, which access itself, its neighbor nodes and hidden nodes, and every node calculates the remaining available bandwidth by deducting the bandwidth reserved in the resource reservation table from the total available bandwidth of the node. Moreover, the BCMR searches in a distributed manner for the paths with the shortest delay conditioned by the bandwidth constraint. Simulation results demonstrate the good performance of BCMR in terms of packet delivery reliability and the delay. BCMR can meet the requirements of real time communication and can be used in the multicast applications with low mobility in wireless ad hoc networks.

Self-Organized Public-Key Management for Mobile Ad Hoc Networks Based on a Bidirectional Trust Model

In traditional networks , the authentication is performed by certificate authoritys（CA）,which can＇t be built in distributed mobile Ad Hoc Networks however. In this pa per, we propose a fully self-organized public key management based on bidirectional trust model without any centralized authority that allows users to generate their public-private key pairs, to issue certificates, and the trust relation spreads rationally according to the truly human relations. In contrast with the traditional self-organized public-key management, the average certificates paths get more short, the authentication passing rate gets more high and the most important is that the bidirectional trust based model satisfys the trust re quirement of hosts better.

Reliable adaptive multicast protocol in wireless Ad hoc networks

In wireless ad hoe network environments, every link is wireless and every node is mobile. Those features make data lost easily as well as multicasting inefficient and unreliable. Moreover, Efficient and reliable multicast in wireless ad hoe network is a difficult issue. It is a major challenge to transmission delays and packet losses due to link changes of a multicast tree at the provision of high delivery ratio for each packet transmission in wireless ad hoe network environment. In this paler, we propose and evaluate Reliable Adaptive Multicast Protocol （RAMP） based on a relay node concept. Relay nodes are placed along the multieast tree. Data recovery is done between relay nodes. RAMP supports a reliable multicasting suitable for mobile ad hoe network by reducing the number of packet retransmissions. We compare RAMP with SRM （Scalable Reliable Multicast）. Simulation results show that the RAMP has high delivery ratio and low end-to-end delay for packet transmsission.

A load-balanced minimum energy routing algorithm for Wireless Ad Hoc Sensor Networks

Wireless Ad Hoc Sensor Networks (WSNs) have received considerable academia research attention at present. The energy-constraint sensor nodes in WSNs operate on limited batteries, so it is a very important issue to use energy efficiently and reduce power consumption. To maximize the network lifetime, it is essential to prolong each individual node’s lifetime through minimizing the transmission energy consumption, so that many minimum energy routing schemes for traditional mobile ad hoc network have been developed for this reason. This paper presents a novel minimum energy routing algorithm named Load-Balanced Minimum Energy Routing (LBMER) for WSNs considering both sensor nodes’ energy consumption status and the sensor nodes’ hierarchical congestion levels, which uses mixture of energy balance and traffic balance to solve the problem of “hot spots” of WSNs and avoid the situation of “hot spots” sensor nodes using their energy at much higher rate and die much faster than the other nodes. The path router established by LBMER will not be very congested and the traffic will be distributed evenly in the WSNs. Simulation results verified that the LBMER performance is better than that of Min-Hop routing and the existing minimum energy routing scheme MTPR (Total Transmission Power Routing).

Traffic-Aware Channelization Medium Access Control for Wireless Ad Hoc Networks

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.

Virtual reality mobility model for wireless ad hoc networks

For wireless ad hoc networks simulation, node＇s mobility pattern and traffic pattern are two key elements. A new simulation model is presented based on the virtual reality collision detection algorithm in obstacle environment, and the model uses the path planning method to avoid obstacles and to compute the node＇s moving path. Obstacles also affect node＇s signal propagation. Considering these factors, this study implements the mobility model for wireless ad hoc networks. Simulation results show that the model has a significant impact on the performance of protocols.

Delay-Based Cross-Layer QoS Scheme for Video Streaming in Wireless Ad Hoc Networks

With correlating with human perception, quality of experience(Qo E) is also an important measurement in evaluation of video quality in addition to quality of service(Qo S). A cross-layer scheme based on Lyapunov optimization framework for H.264/AVC video streaming over wireless Ad hoc networks is proposed, with increasing both Qo E and Qo S performances. Different from existing works, this scheme routes and schedules video packets according to the statuses of the frame buffers at the destination nodes to reduce buffer underflows and to increase video playout continuity. The waiting time of head-ofline packets of data queues are considered in routing and scheduling to reduce the average end-to-end delay of video sessions. Different types of packets are allocated with different priorities according to their generated rates under H.264/AVC. To reduce the computational complexity, a distributed media access control policy and a power control algorithm cooperating with the media access policy are proposed. Simulation results show that, compared with existing schemes, this scheme can improve both the Qo S and Qo E performances. The average peak signal-to-noise ratio(PSNR) of the received video streams is also increased.

A Preamble-Based Broadcasting Technique for Wireless Ad Hoc Sensor Networks

Broadcasting is a fundamental operation in any wireless networks, more so in wireless ad hoc sensor networks, where each sensor node has limited transmission range as well as battery power. Although broadcasting in wireless ad hoc sensor networks has many advantages but it can cause serious problems like-broadcast storm, which could cause a lot of contention, redundant retransmission, collision and most importantly, drain immense amount of energy from limited battery powered sensor nodes. In this work, our objective is to reduce the number of retransmission and energy consumption of sensor nodes by using the duty cycle property of wireless ad hoc sensor networks. We propose a preamble-based broadcasting technique for wireless ad hoc sensor networks. We show that in dense wireless ad hoc sensor networks a small size preamble can give maximum network-wide data dissemination rather than using the large preamble, which will only consume immense amount of energy during packet reception.

IP ADDRESS AUTOCONFIGURATION FOR WIRELESS AD HOC NETWORKS

A novel mechanism was specified by which a node in ad hoc network may autoconfigure an IP address which is unique throughout the mobile ad hoc network. This new algorithm imposes less and constant overhead and delay in obtaining an IP address, and fully utilizes the available addresses space of an ad hoc network, and independent of the existing routing protocol, and less prone to security threats. Moreover, a new Join/Leave mechanism was proposed as an enhancement to the new IP address autoconfiguration algorithm, to support the overall operation of the existing routing protocol of wireless ad hoc networks.

Linear Network Coding Based Fast Data Synchronization for Wireless Ad Hoc Networks with Controlled Topology

Fast data synchronization in wireless ad hoc networks is a challenging and critical problem.It is fundamental for efficient information fusion,control and decision in distributed systems.Previously,distributed data synchronization was mainly studied in the latency-tolerant distributed databases,or assuming the general model of wireless ad hoc networks.In this paper,we propose a pair of linear network coding(NC)and all-to-all broadcast based fast data synchronization algorithms for wireless ad hoc networks whose topology is under operator’s control.We consider both data block selection and transmitting node selection for exploiting the benefits of NC.Instead of using the store-and-forward protocol as in the conventional uncoded approach,a compute-and-forward protocol is used in our scheme,which improves the transmission efficiency.The performance of the proposed algorithms is studied under different values of network size,network connection degree,and per-hop packet error rate.Simulation results demonstrate that our algorithms significantly reduce the times slots used for data synchronization compared with the baseline that does not use NC.

Using Bayesian Game Model for Intrusion Detection in Wireless Ad Hoc Networks

Wireless ad ho network is becoming a new research fronter, in which security is an important issue. Usually some nodes act maliciously and they are able to do different kinds of Denial of Service (Dos). Because of the limited resource, intrusion detection system (IDS) runs all the time to detect intrusion of the attacker which is a costly overhead. In our model, we use game theory to model the interactions between the intrusion detection system and the attacker, and a realistic model is given by using Bayesian game. We solve the game by finding the Bayesian Nash equilibrium. The results of our analysis show that the IDS could work intermittently without compromising on its effectiveness. At the end of this paper, we provide an experiment to verify the rationality and effectiveness of the proposed model.

ON THE CAPACITY REGION OF WIRELESS AD HOC RELAY NETWORKS

Network capacity is a key characteristic to evaluate the performance of wireless networks, The goal of this paper is to study the capacity of wireless ad hoe relay network. In the model, there is at lnost ns source nodes transmitting signal simultaneously in the network and the arbitrarily complex network coding is allowed. The upper capacity bound of the network model are derived From the max-flow rain-cut theorem and the lower capacity bound are obtained by the rate-distortion function For the Gaussian source. Finally, simulation results show that the upper network capacity will decrease as the number of source nodes is increased.

Joint routing and rate allocation for multiple video streams in ad-hoc wireless networks

The support for multiple video streams in an ad-hoc wireless network requires appropriate routing and rate allocation measures ascertaining the set of links for transmitting each stream and the encoding rate of the video to be delivered over the chosen links. The routing and rate allocation procedures impact the sustained quality of each video stream measured as the mean squared error (MSE) distortion at the receiver, and the overall network congestion in terms of queuing delay per link. We study the trade-off between these two competing objectives in a convex optimization formulation, and discuss both centralized and dis- tributed solutions for joint routing and rate allocation for multiple streams. For each stream, the optimal allocated rate strikes a balance between the selfish motive of minimizing video distortion and the global good of minimizing network congestions, while the routes are chosen over the least-congested links in the network. In addition to detailed analysis, network simulation results using ns-2 are presented for studying the optimal choice of parameters and to confirm the effectiveness of the proposed measures.

Fair rate control for wireless ad-hoc networks with time varying channel capacities

We consider the problem of fair rate control for wireless ad-hoc networks with time varying channel capacities. The interaction between links in wireless ad-hoc networks introduces additional constraints on the flow rate. A primal-dual algorithm that guarantees fair rate control is proved to be trajectory stable. Various fairness indexes are obtained by choosing the specified form of the utility functions, and the numerical results validate the effectiveness of the proposed algorithm.

Subarea Tree Routing (STR) in Multi-hop Wireless Ad hoc Networks

Subarea Tree Routing (STR), a new routing protocol for multi-hop wireless ad hoc networks, is proposed. The novelty of the STR protocol is to divide the whole network into many subareas constructed as a result of establishing subarea trees. Its main idea is to identify root nodes by manual configuration or auto-discovery process firstly, then the root nodes originate the process of establishing subarea trees, and finally each node either joins in a subarea tree or become an interconnect node. STR belongs to hierarchical routing protocol and does not attempt to consistently maintain routing information in every node. Furthermore, through the use of tree’s intrinsic routing function, the STR protocol exhibits hybrid behavior of proactive and on-demand routing protocols. We prove the correctness of STR, and our simulation results show that the pro-posed scheme achieves lower route discovery delays, lower route discovery load and better performance of normalized routing load in large, mobile, ad hoc networks as compared with AODV.

基于信号方差的Ad-Hoc网络路由算法

为解决Ad-Hoc路由协议查找路径过程中,由于从源节点到目的节点的传输路径会因为某个节点移动而导致整条路径中断,造成最短路径通常不是最稳定路径问题,提出一个以信号方差为基础的路由选择方法。通过侦测到的节点间信号强度,观察其信号变动程度,当信号变动值很小时,表示该节点间的链接处于稳定的状态,较不易断线。这些稳定链接组成的路径将是一条最稳定的路径。通过实验仿真验证,利用该方法所选路由,路径的稳定度明显优于其它算法。

Secure and Energy Concise Route Revamp Technique in Wireless Sensor Networks

Energy conservation has become a significant consideration in wireless sensor networks(WSN).In the sensor network,the sensor nodes have internal batteries,and as a result,they expire after a certain period.As a result,expanding the life duration of sensing devices by improving data depletion in an effective and sustainable energy-efficient way remains a challenge.Also,the clustering strategy employs to enhance or extend the life cycle of WSNs.We identify the supervisory head node(SH)or cluster head(CH)in every grouping considered the feasible strategy for power-saving route discovery in the clustering model,which diminishes the communication overhead in the WSN.However,the critical issue was determining the best SH for ensuring timely communication services.Our secure and energy concise route revamp technology(SECRET)protocol involves selecting an energy-concise cluster head(ECH)and route revamping to optimize navigation.The sensors transmit information over the ECH,which delivers the information to the base station via the determined optimal path using our strategy for effective data transmission.We modeled our methods to accom-plish power-efficient multi-hop routing.Furthermore,protected navigation helps to preserve energy when routing.The suggested solution improves energy savings,packet delivery ratio(PDR),route latency(RL),network lifetime(NL),and scalability.

AN MAC PROTOCOL SUPPORTING MULTIPLE TRAFFIC OVER MOBILE AD HOC NETWORKS

This letter presents the design and performance of a multi-channel MAC protocol that supports multiple traffics for IEEE 802.11 mobile ad-hoc networks. The dynamic channel selection scheme by receiver decision is implemented and the number of the data channel is independent of the network topology. The priority for real-time traffic is assured by the proposed adaptive back off algorithm and different IFS. The protocol is evaluated by simulation and the results have shown that it can support multiple traffics and the performance is better than the performance that IEEE 802.11 standard provides.

Cognitive Radio Ad-Hoc Networks: Some New Results on Multi-Channel Hidden Terminal Problem

Recently the Cognitive Radio (CR), in particular the CR Ad-Hoc Network (CRAHN) technology appears as a burgeoning area in wireless communication that enables utilization of limited network resources in more efficient and intelligent way;studies indicate that opportunistic utilization of the available radio frequency spectrum, without interfering the licensed primary user (PU) could be made. This paper presents some simulation based performance of the Multi-Channel Hidden Terminal (MCHT) problem on CRAHNs;new observations on the effect of the number of channels on certain PU-activity metrics, e.g., delay and throughput, are described.