Performance analysis of contention based bandwidth request mechanisms in WiMAX networks

This article is posted here with the permission of IEEE. The official version can be obtained from the DOI below - Copyright @ 2010 IEEEWiMAX networks have received wide attention as they support high data rate access and amazing ubiquitous connectivity with great quality-of-service (QoS) capabilities. In order to support QoS, bandwidth request (BW-REQ) mechanisms are suggested in the WiMAX standard for resource reservation, in which subscriber stations send BW-REQs to a base station which can grant or reject the requests according to the available radio resources. In this paper we propose a new analytical model for the performance analysis of various contention based bandwidth request mechanisms, including grouping and no-grouping schemes, as suggested in the WiMAX standard. Our analytical model covers both unsaturated and saturated traffic load conditions in both error-free and error-prone wireless channels. The accuracy of this model is verified by various simulation results. Our results show that the grouping mechanism outperforms the no-grouping mechanism when the system load is high, but it is not preferable when the system load is light. The channel noise degrades the performance of both throughput and delay.This work was supported by the U.K. Engineering and Physical Sciences Research Council (EPSRC) under Grant EP/G070350/1 and by the Brunel University’s BRIEF Award

Efficient Resource Management Mechanism for 802.16 Wireless Networks Based on Weighted Fair Queuing

Wireless Networking continues on its path of being one of the most commonly used means of communication. The evolution of this technology has taken place through the design of various protocols. Some common wireless protocols are the WLAN, 802.16 or WiMAX, and the emerging 802.20, which specializes in high speed vehicular networks, taking the concept from 802.16 to higher levels of performance. As with any large network, congestion becomes an important issue. Congestion gains importance as more hosts join a wireless network. In most cases, congestion is caused by the lack of an efficient mechanism to deal with exponential increases in host devices. This can effectively lead to very huge bottlenecks in the network causing slow sluggish performance, which may eventually reduce the speed of the network. With continuous advancement being the trend in this technology, the proposal of an efficient scheme for wireless resource allocation is an important solution to the problem of congestion. The primary area of focus will be the emerging standard for wireless networks, the 802.16 or “WiMAX”. This project, attempts to propose a mechanism for an effective resource management mechanism between subscriber stations and the corresponding base station

Study of IEEE802.16e standards to improve QoS throughput and delay analysis of PMP MAC Scheduling algorithms

WiMAX has two modes of operation: Point to Multi Point (PMP) mode and Mesh mode. PMP mode consists of one BS and multiple SS.The Wi-MAX is IEEE 802.16 Wireless network standard which recently used for Broadband Wireless communication. Now days to satisfy the highest demand of broadband wireless access by using various resource of bandwidth is a biggest challenge for Researchers, in this time WiMAX (Worldwide Interoperability for Microwave Access) emerged as a better solution to fulfil that demand. To provide authentic services for voice, data and videos WiMAX define the various QoS parameters at Media Access Control (MAC) layer. WiMAX structure is based on IEEE 802.16 OSI standard and defines the PMP (Point to Multipoint) and Mesh modes for transmission of information. In this study, cross-layer scheduling algorithm for Wimax networks has been proposed

Investigation of efficient resource allocation schemes for WiMAX networks

This thesis was submitted for the degree of Master of Philosophy and was awarded by Brunel University on 9 July 2008.WiMax (Worldwide Interoperability for Microwave Access) is a promising wireless technology with the aim of providing the last mile wireless broadband access designed for both fixed and mobile consumers as an alternative solution to the wired DSL and cable access schemes. The purpose of this research project is to investigate efficient resource allocation algorithms for WiMax. To achieve this goal, we investigate efficient PHY layer Partial Usage of SubCarriers (PUSC) allocation as well as MAC layer piggyback bandwidth request mechanisms. At the PHY layer we proposed improvements on the Uplink and Downlink PUSC subcarrier allocation scheme. For the Uplink PUSC we suggested a method by allocating different frequencies to neighbouring cells in combination with the Integer Frequency Reuse (IFR) and Fractional Frequency Reuse (FFR) in order to reduce interferences and collisions. The simulation results exhibit that collision rates can be reduced to zero for both IFR and FFR patterns with the proposed improvement by assuming that perfect power control is used in the system. In addition, there is no collision at cell edges. The results also show that FFR patterns achieve lower inter-cell interference and higher capacities as compared to the IFR patterns. For the Downlink PUSC we introduced an offset scheme with the purpose of increasing the number of users in the system. At the MAC layer we propose an improvement on the piggyback bandwidth request mechanism by increasing the size of the piggyback bandwidth request in order to reduce the number of bandwidth requests and hence improve the resource utilisation. The simulation results demonstrate that our improved scheme achieves higher throughput, less delay and packet loss rates as compared to the standardised piggyback bandwidth request mechanism