Abstract
Orthogonal Frequency Division Multiplexing (OFDM) with dynamic scheduling and resource allocation is a key component of most emerging broadband wireless access networks such as WiMAX and LTE (Long Term Evolution) for 3GPP. However, scheduling and resource allocation in an OFDM system is complicated, especially in the uplink due to two reasons: (i) the discrete nature of subchannel assignments, and (ii) the heterogeneity of the users' subchannel conditions, individual resource constraints and application requirements. We approach this problem using a gradient-based scheduling framework. Physical layer resources (bandwidth and power) are allocated to maximize the projection onto the gradient of a total system utility function which models application-layer Quality of Service (QoS). This is formulated as a convex optimization problem and solved using a dual decomposition approach. This optimal solution has prohibitively high computational complexity but reveals guiding principles that we use to generate lower complexity sub-optimal algorithms. We analyze the complexity and compare the performance of these algorithms via extensive simulations.
| Original language | English (US) |
|---|---|
| Article number | 4769397 |
| Pages (from-to) | 226-234 |
| Number of pages | 9 |
| Journal | IEEE Journal on Selected Areas in Communications |
| Volume | 27 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 2009 |
Funding
R. Berry was supported in part by the Motorola-Northwestern Center for Seamless Communications and NSF CAREER award CCR-0238382. The work was partially presented at the 2007 Asilomar Conference on Signals, Systems and Computers. Manuscript received 15 January 2008; revised 15 August 2008. Part of this work was done while J. Huang and V. G. Subramanian were at Motorola. J. Huang is supported by the Competitive Earmarked Research Grants (Project Number 412308) established under the University Grant Committee of the Hong Kong Special Administrative Region, China, the Direct Grant (Project Number C001-2050398) of The Chinese University of Hong Kong, and the National Key Technology R&D Program (Project Number 2007BAH17B04) established by the Ministry of Science and Technology of the People’s Republic of China. V. Subramanian is supported by SFI grant 03/IN3/I346.
Keywords
- Dual decomposition
- Optimization
- Orthogonal Frequency Division Multiplexing (OFDM)
- Resource allocation
- Scheduling
- Uplink communications
ASJC Scopus subject areas
- Computer Networks and Communications
- Electrical and Electronic Engineering
