Bo Rong

Call Admission Control Optimization in WiMAX Networks

Worldwide interoperability for microwave access (WiMAX) is a promising technology for last-mile Internet access, particularly in the areas where wired infrastructures are not available. In a WiMAX network, call admission control (CAC) is deployed to effectively control different traffic loads and prevent the network from being overloaded. In this paper, we propose a framework of a 2-D CAC to accommodate various features of WiMAX networks. Specifically, we decompose the 2-D uplink and downlink WiMAX CAC problem into two independent 1-D CAC problems and formulate the 1-D CAC optimization, in which the demands of service providers and subscribers are jointly taken into account. To solve the optimization problem, we develop a utility- and fairness-constrained optimal revenue policy, as well as its corresponding approximation algorithm. Simulation results are presented to demonstrate the effectiveness of the proposed WiMAX CAC approach.

Integrated Downlink Resource Management for Multiservice WiMAX Networks

In this paper, we propose a novel downlink resource management framework for multiservice WiMAX (worldwide interoperability for microwave access) networks. Our framework consists of two major components: adaptive power allocation (APA) and call admission control (CAC). We formulate each of them as an optimization problem, where the demands of both WiMAX service providers and subscribers are taken into account. To solve the optimization problems, we develop a fairness-constrained greedy revenue algorithm for downlink APA optimization and a utility-constrained greedy approximation algorithm for downlink CAC optimization. Our simulation results show that, when combining the APA and CAC optimization methods together, the proposed resource management framework can meet the expectations of both service providers and subscribers

Enhanced QoS Multicast Routing in Wireless Mesh Networks

Wireless mesh network (WMN) has recently emerged as a promising technology for next-generation wireless networking. In WMNs, many important applications, such as mobile TV and video/audio conferencing, require the support of multicast communication with quality-of-service (QoS) guarantee. In this paper, we address the QoS multicast routing issue in WMNs. Specifically, we propose a novel network graph preprocessing approach to enable traffic engineering and enhance the performance of QoS multicast routing algorithms. In this approach, we employ prioritized admission control scheme and develop a utility-constrained optimal priority gain policy. Extensive simulation results show that our approach can significantly improve the performance of QoS multicast routing in WMNs.

Virtual backbone based on MCDS for topology control in wireless ad hoc networks

This paper proposes to utilize virtual backbone to handle control messages in ad hoc networks. The virtual backbone is built by using the Minimum Connected Dominating Set (MCDS) on a graph. The first part of this paper presents a new algorithm to construct the MCDS. The construction of the MCDS is formulated using the linear programming approach. We compared the performance of this procedure with those other previous approaches, and we find that our approach is less complex and gives the nearest solution to the optimal one. The second part of this paper presents different techniques of diffusion in ad hoc networks such as flooding, clustering, MP relay, and backbone based on MCDS, etc. The flooding technique is simple and efficient, but it is expensive in term of bandwidth, and causes excessive flows of message etc. Simulation results show that the approach of virtual backbone based MCDS outperforms flooding and MP relay.

An enhanced SIP proxy server for wireless VoIP in wireless mesh networks

The wireless mesh network (WMN) has emerged recently as a promising technology for next-generation wireless networking. In WMNs, it is important to provide high quality multimedia service in a flexible and intelligent manner. To address this issue in this article, we study the Session Initiation Protocol (SIP) for wireless voice over IP (VoIP) applications. Especially, we investigate the technical challenges in WMN VoIP systems and propose a design of an enhanced SIP proxy server to overcome them. An analysis of the signaling process and a study of simulation results have shown the advantages of our proposed approach.

Downlink Call Admission Control in Multiservice WiMAX Networks

WiMAX (Worldwide Interoperability for Microwave Access) is a promising technology for last-mile broadband Internet access. In multiservice WiMAX networks, call admission control (CAC) plays a critical role. In this paper, we address CAC problem from the perspectives of both WiMAX service providers and subscribers. Specifically, we formulate CAC as an optimization problem, in which the demands of service providers and subscribers are taken into account. To solve the optimization problem, we develop a utility and fairness constrained greedy revenue algorithm. Simulation results show that the proposed approach has satisfying performance.

Mobility prediction aided dynamic multicast routing in MANET

Nodes in a mobile ad hoc network (MANET) are free to move at anytime and to anywhere. This mobility feature makes multicast in MANET a typical dynamic multicast case, where group members are likely to leave and rejoin the multicast session frequently. To provide an efficient routing scheme in such a dynamic multicast environment, we propose a mobility prediction aided dynamic multicast routing (MPADMR) algorithm. This algorithm contains two steps, the construction of a link lifetime constrained minimum hop-count multicast tree and a dynamic multicast tree maintenance procedure. We employ OPNET simulation to evaluate the performance of this dynamic multicast routing algorithm. The simulation results show that MPADMR has strong capability of handling the dynamics of group members

Traffic aggregation based SIP over MPLS network architecture

The next generation communication system will provide high quality multimedia service in a more flexible and intelligent manner. In this paper, we propose a new SIP over MPLS network architecture to achieve this goal. To integrate SIP protocol with the traffic engineering (TE) function of MPLS network seamlessly and facilitate SIP call setup, the SIP-MPLS traffic aggregation server (TA server) is highlighted in this new architecture. Furthermore, the call admission and bandwidth renegotiation algorithms running on the TA server are investigated carefully. We rely on OPNET simulation to assess the performance of our network architecture and the capability of different call admission and bandwidth renegotiation algorithms. The simulation results show that the algorithm of TBCA-BP is a suitable candidate for accomplishing the call admission and bandwidth renegotiation task due to its satisfying performance, and our network architecture is able to shorten the SIP call setup delay greatly by using the TA server.

Multiple Description Coding Based Video Multicast over Heterogeneous Wireless Ad Hoc Networks

In this paper, we investigate how Multiple Description Coding (MDC) can improve the users satisfaction for a group of heterogeneous destinations for video multicast over wireless ad hoc networks. Specifically, we explore the independent-description property of MDC with multiple paths to improve the users satisfaction. In our approach, the assignment of multiple description (MD) video is randomly done by a multicast source node. Based on the assignment of MD video, the multicast source constructs multiple multicast trees accordingly. Simulation results demonstrate that our approach can achieve higher users satisfaction regardless of the multicast group size.

A design of optimal key management scheme for secure and survivable wireless sensor networks

In this paper, we investigate optimal key management design for secure and survivable heterogeneous wireless sensor networks (HWSNs). In particular, we formulate the key management problem as a multi-objective optimization problem, in which the cost of the sensor network, and the security and survivability metrics of the sensor network are taken into account. To solve the multi-objective optimization model, we develop a genetic algorithm (GA)-based approach that can efficiently obtain near-optimal solutions. We show the performance of our scheme through extensive numerical results. With a small amount of powerful sensor nodes in HWSN, we can balance the cost of the sensor network and the resilience of the sensor network with the required security constraint in different hostile environment. Copyright