<p>This paper is a study of IEEE Standard 802.16 Medium Access Control (MAC) Layer in Distributed Mesh Networks. IEEE Standard 802.16 is a Wireless Metropolitan Area Network (WMAN) technology that can connect different IEEE 802.11 (Wifi) host post with each other and to other parts of internet. It can provide network for a wireless router and at the same time this router can be installed in the office, house or university.</p><p>WiMAX (Worldwide Interoperability for Microwave Access) is a certification mark for products that pass conformity and interoperability tests for the IEEE 802.16 standards. Products that pass the conformity tests for WiMAX are capable of forming wireless connections between them to permit the carrying of internet packet data. The idea of WiMAX is similar than Wi-Fi but it is not the same. It is a step much higher than Wi-Fi because it is focused to offer internet for a whole city.</p><p>It has much higher capacity and longer distances. IEEE 802.16 defines a MAC Layer that supports multiple physical layer (PHY) Specifications and different topologies; Point to Multipoint (PMP) and Mesh Networks. In this first topology there exist a Base Station (BS) that have direct links with all the Subscriber Stations (SS). If any Subscriber Station requires transmitting to another SS, the message must convey the Base Station.</p>

Heterogeneous wireless networks will be dominant in the next-generation wireless networks with the integration of various wireless access networks. Wireless mesh networks will become to a key technology as an economically viable solution for wide deployment of high speed, scalable and ubiquitous wireless Internet services. In this thesis, we consider an interworking architecture of wireless mesh backbone and propose an effective vertical handoff scheme between 802.11 and 802.16 wireless access networks. The proposed vertical handoff scheme aims at reducing handoff signaling overhead on the wireless backbone and providing a low handoff delay to mobile nodes. The handoff signaling procedure in different scenarios is discussed. Together with call admission control, the vertical handoff scheme directs a new call request in the 802.11 network to the 802.16 network, if the admission of the new call in the 802.11 network can degrade quality-of-service (QoS) of the existing real-time traffic flows. Simulation results demonstrate the performance of the handoff scheme with respect to signaling cost, handoff delay, and QoS support.

This paper is a study of IEEE Standard 802.16 Medium Access Control (MAC) Layer in Distributed Mesh Networks. IEEE Standard 802.16 is a Wireless Metropolitan Area Network (WMAN) technology that can connect different IEEE 802.11 (Wifi) host post with each other and to other parts of internet. It can provide network for a wireless router and at the same time this router can be installed in the office, house or university. WiMAX (Worldwide Interoperability for Microwave Access) is a certification mark for products that pass conformity and interoperability tests for the IEEE 802.16 standards. Products that pass the conformity tests for WiMAX are capable of forming wireless connections between them to permit the carrying of internet packet data. The idea of WiMAX is similar than Wi-Fi but it is not the same. It is a step much higher than Wi-Fi because it is focused to offer internet for a whole city. It has much higher capacity and longer distances. IEEE 802.16 defines a MAC Layer that supports multiple physical layer (PHY) Specifications and different topologies; Point to Multipoint (PMP) and Mesh Networks. In this first topology there exist a Base Station (BS) that have direct links with all the Subscriber Stations (SS). If any Subscriber Station requires transmitting to another SS, the message must convey the Base Station.

Heterogeneous wireless networks will be dominant in the next-generation wireless networks with the integration of various wireless access networks. Wireless mesh networks will become to a key technology as an economically viable solution for wide deployment of high speed, scalable and ubiquitous wireless Internet services. In this thesis, we consider an interworking architecture of wireless mesh backbone and propose an effective vertical handoff scheme between 802.11 and 802.16 wireless access networks. The proposed vertical handoff scheme aims at reducing handoff signaling overhead on the wireless backbone and providing a low handoff delay to mobile nodes. The handoff signaling procedure in different scenarios is discussed. Together with call admission control, the vertical handoff scheme directs a new call request in the 802.11 network to the 802.16 network, if the admission of the new call in the 802.11 network can degrade quality-of-service (QoS) of the existing real-time traffic flows. Simulation results demonstrate the performance of the handoff scheme with respect to signaling cost, handoff delay, and QoS support.

Multimedia applications in wireless communication have shown notable increases over recent years. Specifically, Quality of Service (QoS) has become an important support mechanism in the context of a variety of applications which utilize network resources. The IEEE 802.16 standard for Wireless Metropolitan Area Networks (WirelessMAN) provides a complete QoS control structure designed to enable flow isolation and service differentiation over the common wireless interface. Although the media access control (MAC) mechanisms defined in this standard can offer predefined QoS provisioning on a pre-connection basis (additionally, many algorithms have been addressed to support QoS guarantees for various kinds of applications), the design for a stable, efficient and flexible MAC scheduling algorithm for such QoS provisioning still remains to be discovered. In this paper, we propose a QoS control scheme, Efficient Bandwidth Allocation (EBA), for the WirelessMAN system. Notably, this schedule enables predefined service parameters to control the service provided for each uplink connection and it provides each connection with different service opportunities such that the BS could allocate the most suitable bandwidth constantly for each connection with the various QoS parameters. Moreover, through MAC layer resource allocation, the proposed algorithm is capable of providing QoS guarantee for the SSs under different distance.

Thèse de doctorat : Informatique : Evry-Val d'Essonne : 2008. / Titre provenant de l'écran-titre.

Thèse de doctorat : Informatique : Evry-Val d'Essonne : 2009. / Titre provenant de l'écran-titre.

Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, December 2009. / Thesis Advisor(s): McEachen, John C. ; Loomis, Herschel H. Second Reader: Garcia, Vicente C. "December 2009." Description based on title screen as viewed on January 27, 2010. Author(s) subject terms: 802.16, WiMAX, geolocation, ranging, timing adjust. Includes bibliographical references (p. 71-72). Also available in print.

M. Tech. Electrical Engineering. / Discusses the study as limited to the formal specification/modelling and formal verification of protocols proposed and applicable to the initial network entry procedure in WiMAX networks. Secondly, formal specification of the existing protocols under consideration will be based on their informal specification available in the literature and not on proprietary protocols for which little or no information is available. Thirdly, this research work does not intend to wipe out the state space explosion problem but rather applies existing optimization techniques to supress it. Finally, the study does not assess the usability performance impact of the proposed security scheme and thus recommends that this analysis should be done as future work to evaluate the functionality and soundness of deploying the proposed security scheme.

IEEE 802.16標準是針對無線城域網路(Wireless Metropolitan Area Network)而設計的，它支援服務品質(QoS)，而且具有相當高的傳輸速率。每一種應用服務都有不同的型態，根據這些不同的型態，802.16 定義了四個不同的服務品質類別。然而，最關鍵的部份－封包排程卻沒有被定義在802.16標準裡面。在這篇論文中，我們提出了一套完整的允入控管(call admission control)和上行封包排程的架構。首先，我們先以令牌桶(token bucket)機制為基礎，設計了一套802.16專用的允入控管和上行封包排程的模組。接著我們介紹如何將令牌桶機制套用至一般的連線。我們找出了一個預測連線的延遲(delay)和漏失率(loss rate)的模型，接著可以利用這個模型，並透過簡單的搜尋演算法來找出適合的令牌速率和令牌桶的大小。模擬的結果表示，我們的允入控管和上行封包排程能夠確實對具有即時性質的連線的提供保證，且我們將令牌桶機制套用到一般連線的模組也能準確的運作。最後，我們也提出了一個簡單的整合實例並評估其效能。 / The IEEE 802.16 standard was designed for Wireless Metropolitan Area Network (WMAN). It supports QoS and has very high transmission rate. According to different application types, there are four QoS classes defined in the IEEE 802.16 standard. The key part of 802.16 for QoS– packet scheduling, was undefined. In this thesis, a complete call admission control (CAC) and uplink packet scheduling is presented. We first proposed a token-bucket based uplink packet scheduling combined with CAC. Then a model of characterizing traffic flows by token bucket parameters, namely token rate and bucket size, is presented. We proposed a queuing model to predict the delay and loss rate for a token bucket controlled traffic flow. In order to fulfill token bucket based CAC, we need to find appropriate token rate and bucket size for any flows. A simple search algorithm coupled with our queuing model can be used to achieve this. Multiplexing of two traffic flows is also introduced. The simulation results show that our CAC and uplink packet scheduling can promise the delay requirement of real-time flows and prevent each class from starvation. The precision of our token rate estimation model is also validated. Finally, a simple integration of our CAC, uplink scheduling, and multiplexing is evaluated.