A dynamic radio resource management scheme for the IEEE 802.16 band-adaptive modulation and coding mode with proportional rate constraints

• Published in: Transactions on emerging telecommunications technologies 2012-04, Vol.23 (3), p.254-267
• Main Authors: Sokar, Mina A.A., Elsayed, Khaled M.F.
• Format: Article
• Language: English
• Subjects: constrained optimization; fairness; proportional rates; radio resource management; transportation problem; Vogel approximation; WiMAX band-AMC mode
• ISSN: 2161-3915; 2161-3915
• DOI: 10.1002/ett.1529

ABSTRACT In this paper, we consider the problem of downlink resource allocation in the IEEE 802.16 standard based on the orthogonal frequency‐division multiple access physical layer. The objective is to allocate the downlink frequency‐time slots and transmission power to different users such that the total throughput is maximized. The allocation is subject to constraints on the total transmission power and satisfying the quality of service requirements of different users expressed in terms of proportional rates. A three‐step heuristic scheme that incorporates a linear programming technique is proposed. The problem is modelled as an unbalanced transportation problem that is solved to obtain the users' slot assignment. The Vogel approximation method is used to efficiently solve the transportation problem with a slight degradation relative to the optimal solution. The Vogel approximation method gain is shown by replacing it in the three‐step heuristic by simple round‐robin or greedy slot assignment. In terms of total throughput and fairness, it is shown that the proposed scheme is a good compromise between the greedy‐oriented schemes, which aspire to maximize the total system throughput but sacrificing fairness, and a proportional rate constraints scheme introduced in the literature that achieved short‐term fairness but penalizes the total throughput. The study also shows that the proposed scheme consumes a fraction of the time needed by the proportional rate constraints scheme. Copyright © 2011 John Wiley & Sons, Ltd. The problem of downlink resource allocation in the IEEE 802.16 OFDMA band‐AMC mode is addressed. The radio resources are allocated such that the total throughput is maximized subject to constraints on the total transmission power and satisfying the QoS requirements. A heuristic scheme that incorporates an unbalanced transportation problem is proposed. The proposed scheme is a good compromise between the greedy‐oriented schemes which aspire, and a well‐known scheme for satisfying proportional rate constraints in terms of throughput and fairness.