Jin Shan

Performance Evaluation of Bandwidth Allocation in 802.16j Mobile Multi-Hop Relay Networks

Being an evolution of IEEE 802.16e, IEEE 802.16j mobile multi-hop relay (MMR) is proposed to gain coverage extension and throughput enhancement. This research conducts theoretical analysis and performance evaluation on the on-demand bandwidth allocation in IEEE 802.16j MMR networks. Theoretical analysis shows that such systems using conventional bandwidth allocation will seriously suffer from low bandwidth utilization. We then develop a new, spectrum efficiency based adaptive resource allocation algorithm. Simulation results verified that, compared with conventional on-demand bandwidth allocation method, the proposed method is more bandwidth efficient and exhibits better fairness in such networks. In terms of throughput, packet loss rate and delay, the performance of SEBARA algorithm is further evaluated in an OPNET-based 802.16j MMR simulation platform. Both theoretical analysis and simulation indicate the novel method provides an attractive solution for bandwidth allocation in 802.16j MMR networks.

Fair Scheduling in Wireless Multi-Hop Self-backhaul Networks

In this paper, we provide guidelines for high throughput wireless multi-hop self-backhaul networks which at the same time retain fairness. Based on the theoretical analysis results, we propose two fair scheduling strategies: static independent fair scheduling and dynamic joint fair scheduling. Simulations verify that, both schemes can achieve maximum throughput and exhibits fairness between base stations in a multi-hop self-backhaul chain. Moreover, dynamic joint fair scheduling method achieves improved performance in throughput and exhibits better fairness in network environments where asymmetric services are presented.

Bandwidth Allocation for 3-Sector Base Station in 802.16 Single-Hop Self-Backhaul Networks

Though IEEE 802.16 MAC protocols have been proposed to support quality of service (QoS) guarantees for various kinds of applications, they do not suggest how to allocate service bandwidth to fulfill QoS requirements. Most of the traditional methods of bandwidth allocation in wireless networks treat uplink and downlink bandwidth allocation independently. This research conducts theoretical analysis on the on-demand bandwidth allocation in an IEEE 802.16 single-hop self-backhaul network using 3-sector base station. Simulations have shown that such wireless backhaul systems using conventional on-demand bandwidth allocation will seriously suffer from fairness issues among different sectors of the base station. We then develop a new, joint dynamic bandwidth allocation algorithm for IEEE 802.16 single-hop self-backhaul network using 3-sector base station. Simulation results verified that, compared with conventional on-demand bandwidth allocation method, by considering both uplink and downlink bandwidth requests jointly, the proposed method is more bandwidth efficient and exhibits better fairness.

Self-adaptive clock recovery methods for time periodic traffic across packet switched networks

Real-time periodic transmission across packet switched networks that experience stochastic-delays requires clock recovery at the destination. In this paper, improved self-adaptive clock recovery methods are proposed. Since these methods fully consider network characteristics influence to clock recovery, they have the ability to filter out buffer level fluctuation efficiently and remove the negative contribution of delay jitter in clock recovery. As compared to the existing ones, new methods enable the destination clock to be synchronized with the source faster and with more accuracy.