Traffic scheduling for frame length minimization in OFDMA based systems

In this paper, we investigate a scheduling problem in systems adopting OFDMA transmission technique at the physical layer, like WiMAX (IEEE 802.16) systems. In such systems, carriers with different rates must be assigned to users, each carrier being assigned to one user at most, each user can be scheduled on multiple carriers. The objective of our problem is to produce a legal schedule (i.e. one meeting all the system constraints) with minimum length. We first show that the above problem is NP-complete, and thus computationally intractable, even in an extremely simple case. Then, we propose several very simple and fast suboptimal heuristics, and evaluate their average performance by means of simulation experiments. Some of the proposed heuristics perform very well, being in most cases within 10% of the optimal (minimal) schedule length.

[1]  John M. Cioffi,et al.  Increase in capacity of multiuser OFDM system using dynamic subchannel allocation , 2000, VTC2000-Spring. 2000 IEEE 51st Vehicular Technology Conference Proceedings (Cat. No.00CH37026).

[2]  R. Iyengar,et al.  Scheduling Algorithms for Point-to-Multipoint Operation in IEEE 802.16 Networks , 2006, 2006 4th International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks.

[3]  Lisa Zhang,et al.  Scheduling algorithms for multicarrier wireless data systems , 2011, TNET.

[4]  Eytan Modiano,et al.  Logarithmic delay for N × N packet switches under the crossbar constraint , 2007, TNET.

[5]  M. Einhaus,et al.  Comparison of OFDMA Resource Scheduling Strategies with Fair Allocation of Capacity , 2008, 2008 5th IEEE Consumer Communications and Networking Conference.

[6]  Seong-Lyun Kim,et al.  Joint subcarrier and power allocation in uplink OFDMA systems , 2005, IEEE Communications Letters.

[7]  Weijia Jia,et al.  Centralized Scheduling and Channel Assignment in Multi-Channel Single-Transceiver WiMax Mesh Network , 2007, 2007 IEEE Wireless Communications and Networking Conference.

[8]  Anthony Ephremides,et al.  Practical Resource Allocation Algorithms for QoS in OFDMA-Based Wireless Systems , 2008, 2008 5th IEEE Consumer Communications and Networking Conference.

[9]  Selim G. Akl,et al.  Optimal Linear-Time Algorithm for Uplink Scheduling of Packets with Hard or Soft Deadlines in WiMAX , 2008, 2008 IEEE 68th Vehicular Technology Conference.

[10]  Loutfi Nuaymi,et al.  Wimax Technology for Broadband Wireless Access , 2007 .

[11]  John M. Cioffi,et al.  Dual QoS loading algorithms for multicarrier systems offering different CBR services , 1998, Ninth IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (Cat. No.98TH8361).

[12]  David S. Johnson,et al.  Computers and Intractability: A Guide to the Theory of NP-Completeness , 1978 .

[13]  Miroslav Chlebík,et al.  Inapproximability Results for Bounded Variants of Optimization Problems , 2003, FCT.

[14]  Reuven Cohen,et al.  Computational Analysis and Efficient Algorithms for Micro and Macro OFDMA Scheduling , 2008, IEEE INFOCOM 2008 - The 27th Conference on Computer Communications.