Open Access

Fair Adaptive Bandwidth and Subchannel Allocation in the WiMAX Uplink

  • Antoni Morell1Email author,
  • Gonzalo Seco-Granados1 and
  • JoséLópez Vicario1
EURASIP Journal on Wireless Communications and Networking20092009:918261

DOI: 10.1155/2009/918261

Received: 2 July 2008

Accepted: 29 December 2008

Published: 17 February 2009

Abstract

In some modern communication systems, as it is the case of WiMAX, it has been decided to implement Demand Assignment Multiple Access (DAMA) solutions. End-users request transmission opportunities before accessing the system, which provides an efficient way to share system resources. In this paper, we briefly review the PHY and MAC layers of an OFDMA-based WiMAX system, and we propose to use a Network Utility Maximization (NUM) framework to formulate the DAMA strategy foreseen in the uplink of IEEE 802.16. Utility functions are chosen to achieve fair solutions attaining different degrees of fairness and to further support the QoS requirements of the services in the system. Moreover, since the standard allocates resources in a terminal basis but each terminal may support several services, we develop a new decomposition technique, the coupled-decompositions method, that obtains the optimal service flow allocation with a small number of iterations (the improvement is significant when compared to other known solutions). Furthermore, since the PHY layer in mobile WiMAX has the means to adapt the transport capacities of the links between the Base Station (BS) and the Subscriber Stations (SSs), the proposed PHY-MAC cross-layer design uses this extra degree of freedom in order to enhance the network utility.

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Authors’ Affiliations

(1)
Telecommunications and System Engineering Department (TES), Autonomous University of Barcelona (UAB)

Copyright

© Antoni Morell et al. 2009

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.