Resource Allocation in OFDMA: How Load-Balancing Maximizes Throughput When Water-Filling Fails

This paper considers the issue of optimal subcarrier allocation in OFDMA. We show, via a counter example, that water-filling based subcarrier allocation policies, contrary to conventiona l wisdom, fail to provide rate-stability for an otherwise stabilizable OFDMA system. Water-filling is too myopic when conside ring long-time average performance, e.g. delay, queue lengths, and even long-run throughput. This is because such policies ignore variable state (queue length) information, while, in fact, such an information is necessary to gua rantee rate stability and/or to minimize average delay. In this paper, we identify an optimal non-idling policy which balances the queue lengths, when the channel follows an ON/OFF model. In such case, we show that such a policy achieves the minimum holding cost (mean response time) at any time.

[1]  Sergio Benedetto,et al.  Principles of Digital Transmission: With Wireless Applications , 1999 .

[2]  Adam Wolisz,et al.  Subcarrier allocation for variable bit rate video streams in wireless OFDM systems , 2003, 2003 IEEE 58th Vehicular Technology Conference. VTC 2003-Fall (IEEE Cat. No.03CH37484).

[3]  Khaled Ben Letaief,et al.  Multiuser OFDM with adaptive subcarrier, bit, and power allocation , 1999, IEEE J. Sel. Areas Commun..

[4]  Hui Liu,et al.  Dynamic resource allocation with finite buffer constraint in broadband OFDMA networks , 2003, 2003 IEEE Wireless Communications and Networking, 2003. WCNC 2003..

[5]  Mingyan Liu,et al.  On the optimality of an index policy for bandwidth allocation with delayed state observation and differentiated services , 2004, IEEE INFOCOM 2004.

[6]  Leandros Tassiulas,et al.  Dynamic server allocation to parallel queues with randomly varying connectivity , 1993, IEEE Trans. Inf. Theory.

[7]  Demosthenis Teneketzis,et al.  ON THE OPTIMALITY OF AN INDEX RULE IN MULTICHANNEL ALLOCATION FOR SINGLE-HOP MOBILE NETWORKS WITH MULTIPLE SERVICE CLASSES , 2000 .

[8]  Kurt Mehlhorn,et al.  LEDA: a platform for combinatorial and geometric computing , 1997, CACM.

[9]  Guocong Song,et al.  Joint channel-aware and queue-aware data scheduling in multiple shared wireless channels , 2004, 2004 IEEE Wireless Communications and Networking Conference (IEEE Cat. No.04TH8733).

[10]  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).

[11]  S. Pietrzyk,et al.  Multiuser subcarrier allocation for QoS provision in the OFDMA systems , 2002, Proceedings IEEE 56th Vehicular Technology Conference.

[12]  Eytan Modiano,et al.  Transmission Scheduling for Multi-Channel Satellite and Wireless Networks ∗ , 2002 .

[13]  László Lovász,et al.  Semi-matchings for bipartite graphs and load balancing , 2003, J. Algorithms.

[14]  Yong-Hwan Lee,et al.  Transmit power and bit allocations for OFDM systems in a fading channel , 2003, GLOBECOM '03. IEEE Global Telecommunications Conference (IEEE Cat. No.03CH37489).

[15]  Joachim Speidel,et al.  An efficient waterfilling algorithm for multiple access OFDM , 2002, Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE.

[16]  Guocong Song,et al.  Utility-based joint physical-MAC layer optimization in OFDM , 2002, Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE.

[17]  장지호.  Transmit power and bit allocations for OFDM systems in a fading channel , 2003 .

[18]  Sergio Verdú,et al.  Gaussian multiaccess channels with ISI: Capacity region and multiuser water-filling , 1993, IEEE Trans. Inf. Theory.

[19]  Kurt Mehlhorn,et al.  The LEDA Platform of Combinatorial and Geometric Computing , 1997, ICALP.

[20]  Hui Liu,et al.  An efficient multiuser loading algorithm for OFDM-based broadband wireless systems , 2000, Globecom '00 - IEEE. Global Telecommunications Conference. Conference Record (Cat. No.00CH37137).

[21]  Didem Kivanc-Tureli,et al.  Computationally efficient bandwidth allocation and power control for OFDMA , 2003, IEEE Trans. Wirel. Commun..

[22]  Li Yan,et al.  An adaptive subcarrier, bit and power allocation algorithm for multicell OFDM systems , 2003, CCECE 2003 - Canadian Conference on Electrical and Computer Engineering. Toward a Caring and Humane Technology (Cat. No.03CH37436).

[23]  Joachim Speidel,et al.  Efficient Subcarrier Allocation for Multiple Access in OFDM Systems , 2002 .

[24]  Evaggelos Geraniotis,et al.  Adaptive modulation, power allocation and control for OFDM wireless networks , 2000, 11th IEEE International Symposium on Personal Indoor and Mobile Radio Communications. PIMRC 2000. Proceedings (Cat. No.00TH8525).

[25]  Chaohuang Zeng,et al.  Efficient water-filling algorithms for a Gaussian multiaccess channel with ISI , 2000, Vehicular Technology Conference Fall 2000. IEEE VTS Fall VTC2000. 52nd Vehicular Technology Conference (Cat. No.00CH37152).

[26]  Pravin Varaiya,et al.  QoS aware adaptive resource allocation techniques for fair scheduling in OFDMA based broadband wireless access systems , 2003, IEEE Trans. Broadcast..