Quality of Service over Specific Link Layers: state of the art report

The Integrated Services concept is proposed as an enhancement to the current Internet architecture, to provide a better Quality of Service (QoS) than that provided by the traditional Best-Effort service. The features of the Integrated Services are explained in this report. To support Integrated Services, certain requirements are posed on the underlying link layer. These requirements are studied by the Integrated Services over Specific Link Layers (ISSLL) IETF working group. The status of this ongoing research is reported in this document. To be more specific, the solutions to provide Integrated Services over ATM, IEEE 802 LAN technologies and low-bitrate links are evaluated in detail. The ISSLL working group has not yet studied the requirements, that are posed on the underlying link layer, when this link layer is wireless. Therefore, this state of the art report is extended with an identification of the requirements that are posed on the underlying wireless link, to provide differentiated Quality of Service

Scheduling algorithms in broadband wireless networks

Scheduling algorithms that support quality of service (QoS) differentiation and guarantees for wireless data networks are crucial to the development of broadband wireless networks. Wireless communication poses special problems that do not exist in wireline networks, such as time-varying channel capacity and location-dependent errors. Although many mature scheduling algorithms are available for wireline networks, they are not directly applicable in wireless networks because of these special problems. This paper provides a comprehensive and in-depth survey on recent research in wireless scheduling. The problems and difficulties in wireless scheduling are discussed. Various representative algorithms are examined. Their themes of thoughts and pros and cons are compared and analyzed. At the end of the paper, some open questions and future research directions are addressed.published_or_final_versio

A quantitative comparison of multiple access control protocols for wireless ATM

The multiple access control (MAC) problem in a wireless network has intrigued researchers for years. For a broad-band wireless network such as wireless ATM, an effective MAC protocol is very much desired because efficient allocation of channel bandwidth is imperative in accommodating a large user population with satisfactory quality of service. Indeed, MAC protocols for a wireless ATM network in which user traffic requirements are highly heterogeneous (classified into CBR, VBR, and ABR), are even more intricate to design. Considerable research efforts expended in tackling the problem have resulted in a myriad of MAC protocols. While each protocol is individually shown to be effective by the respective designers, it is unclear how these different protocols compare against each other on a unified basis. In this paper, we quantitatively compare seven recently proposed TDMA-based MAC protocols for integrated wireless data and voice services. We first propose a taxonomy of TDMA-based protocols, from which we carefully select seven protocols, namely SCAMA, DTDMA/VR, DTDMA/PR, DQRUMA, DPRMA, DSA++, and PRMA/DA, such that they are devised based on rather orthogonal design philosophies. The objective of our comparison is to highlight the merits and demerits of different protocol designs.published_or_final_versio

On channel-adaptive fair multiple access control

Multiple access control (MAC) of the uplink in a wireless mobile computing system is one of the most important resource allocation problems in that the response time and throughput of user applications (e.g., wireless Web surfing) are critically affected by the efficiency of the MAC protocol. Compared with a traditional MAC problem (e.g., the wireline Ethernet), there are two important new challenges in a modern wireless network: (1) multimedia data with diverse traffic requirements are involved; and (2) the wireless channel has a time-varying quality for each user. Furthermore, a more prominent user requirement is fairness among different users, possibly with different traffic demands. While some protocols have been suggested to handle multimedia data and/or tackling the time-varying channel, there are a number of drawbacks in these existing protocols. The most notable drawback is that the channel model is rather unrealistic - just using a two state Markov chain instead of relying on accurate models of multipath fading and shadowing effects. Another common deficiency is that fairness is ignored. In this paper, we propose to use a new notion of fairness that can capture a realistic channel model, and to integrate a fair queueing scheduling algorithm in a MAC protocol to optimize performance while maintaing fairness among users regardless of their channel states and data types.published_or_final_versio

A performance study of multiple access control protocols for wireless multimedia services

The multiple access control (MAC) problem in a wireless network has intrigued researchers for years. For a broadband wireless multimedia network such as wireless ATM, an effective MAC protocol is very much desired because efficient allocation of channel bandwidth is imperative in accommodating a large user population with satisfactory quality of service. Indeed, MAC protocols for a wireless ATM network, in which user traffic requirements are highly heterogeneous (classified into CBR, VBR, and ABR), are even more intricate to design. Considerable research efforts expended in tackling the problem have resulted in a myriad of MAC protocols. While each protocol is individually shown to be effective by the respective designers, it is unclear how these different protocols compare against each other on a unified basis. We quantitatively compare seven previously proposed TDMA-based MAC protocols for integrated wireless data and voice services. We first propose a taxonomy of TDMA-based protocols, from which we carefully select seven protocols, namely SCAMA, DTDMA/VR, DTDMA/PR, D4RUMA, DPRMA, DSA++, and PRMA/DA, such that they are devised based on rather orthogonal design philosophies. The objective of our comparison is to highlight the merits and demerits of different protocol designs.published_or_final_versio

Multimedia Traffic Engineering in Next Generation Networks

Due to high speed Internet and Multimedia applications, future wireless communication are expected to support multimedia traffic such as voice, video and text with a variety of Quality of Service (QoS) requirements and make efficient use of radio resources. Such kind of traffic requires high level of QoS guarantees. Traffic management is a process of regulating the traffic over network. Since, multimedia traffic is more sensitive, therefore it requires special measures while transmission, especially in wireless networks. There are different queuing disciplines which are used to police the traffic, the Priority Queue and RIO (RED with In/Out) are queuing disciplines, PQ is used to prioritize the traffic, and the later is used to drop the lower priority packets at the time of congestion. Proposed solution is the integration of Priority Queue with RIO, which will serve as a classifier to prioritize the traffic and then it will also serve as a scheduler by dropping lower priority traffic when the congestion state occur. Simulation results show that by applying proposed Traffic Management Strategy (PriRIO), it assigns stable bandwidth to the Multimedia Traffic Flow and enhances its throughput. It also shows that Packet Losses for Multimedia Traffic are very minor, that is, equivalent to none. Further, delay values for Multimedia traffic also remain below the Best Effort traffic flows. Thus, on the basis of these simulation results and analysis, PriRIO outperforms significantly, as compare to other Traffic Management Strategies

System level performance of ATM transmission over a DS-CDMA satellite link.

PhDAbstract not availableEuropean Space Agenc