A-MAC: Adaptive Medium Access Control for Next Generation Wireless Terminals

Abstract

Abstract-Next Generation (NG) wireless networks are envisioned to provide high bandwidth to mobile users via bandwidth aggregation over heterogeneous wireless architectures. NG wireless networks, however, impose challenges due to their architectural heterogeneity in terms of different access schemes, resource allocation techniques as well as diverse quality of service requirements. These heterogeneities must be captured and handled dynamically as mobile terminals roam between different wireless architectures. However, to address these challenges, the existing proposals require either a significant modification in the network structure and in base stations or a completely new architecture, which lead to integration problems in terms of implementation costs, scalability and backward compatibility. Thus, the integration of the existing medium access schemes, e.g., CSMA, TDMA and CDMA, dictates an adaptive and seamless medium access control (MAC) layer that can achieve high network utilization and meet diverse Quality of Service (QoS) requirements. In this paper, an adaptive medium access control (A-MAC) layer is proposed to address the heterogeneities posed by the NG wireless networks. A-MAC introduces a two-layered MAC framework that accomplishes the adaptivity to both architectural heterogeneities and diverse QoS requirements. A novel virtual cube concept is introduced as a unified metric to model heterogeneous access

Adaptive Bandwidth Reservation and Scheduling for Efficient Wireless Telemedicine Traffic Transmission

“…This condition is a much lower bandwidth requirement than the bandwidth requirements of regular VBR video traffic used and satisfied in this paper. In addition, although the average bit rate in [37] is satisfied, there is no mention in of the average video packet dropping achieved with A-MAC. In addition, no urgent traffic, e.g., telemedicine, is included in [36] and [37].…”

“…We also conceptually compare this paper with one practical implementation of telemedicine video traffic [33] and two efficient MAC protocols recently proposed in the literature: one protocol based on WCDMA [36] and one protocol that integrates TDMA, code-division multiple access (CDMA), and carrier sense multiple access (CSMA) [37].…”

“…In [37], the authors propose an adaptive MAC protocol to address the heterogeneities posed by next-generation wireless networks. The protocol is very efficient in using bandwidth from different network to satisfy, as best as possible, the bandwidth requirements of various types of applications; however, the TDMA network is shown in the performance evaluation to be unable to support even relatively small numbers of voice users and can only well serve best effort traffic.…”

“…In addition, no urgent traffic, e.g., telemedicine, is included in [36] and [37]. This condition would mean that the throughput would further drop in [36] and the incapability of the TDMA component to handle the additional VBR traffic would increase in [37] should such an urgent type of traffic be included in the traffic mixture.…”

“…In our view, the basic idea in [37] (MAC protocols that adapt to multiple network structures with QoS-aware procedures) is the direction toward which MAC protocol designs should head in the near future. It is, however, of major importance that each individual access method (e.g., TDMA, CDMA, and WLAN protocol) is designed toward maximizing bandwidth utilization while guaranteeing the QoS of even the most urgent types of traffic.…”