Skip to main content

Adaptive Downlink Resource Allocation Strategies for Real-Time Data Services in OFDM Cellular Systems


This paper presents a detailed performance analysis of adaptive downlink resource allocation based on users' instantaneous channel responses using power minimization (PM) and bandwidth constrained power minimization (BCPM) strategies. This study shows that, in cellular systems, where interference is a dominant factor, the link outage performance of a resource allocation strategy varies significantly depending on the user channel parameters. In particular, both analytical and simulation results indicate that the PM strategy outperforms BCPM in a mild shadowing environment. However, in severe shadowing conditions, this trend is reversed. This assessment holds true for both flat and frequency-selective fading.



  1. Mohr W, Konhäuser W: Access network evolution beyond third generation mobile communications. IEEE Communications Magazine 2000,38(12):122–133. 10.1109/35.888266

    Article  Google Scholar 

  2. Wong CY, Cheng RS, Letaief KB, Murch RD: Multiuser OFDM with adaptive subcarrier, bit, and power allocation. IEEE Journal on Selected Areas in Communications 1999,17(10):1747–1758. 10.1109/49.793310

    Article  Google Scholar 

  3. Rhee W, Cioffi JM: Increase in capacity of multiuser OFDM system using dynamic subchannel allocation. Proceedings of 51st IEEE Vehicular Technology Conference (VTC '00), May 2000, Tokyo, Japan 2: 1085–1089.

    Google Scholar 

  4. Song G, Li Y: Cross-layer optimization for OFDM wireless networks - part I: theoretical framework. IEEE Transactions on Wireless Communications 2005,4(2):614–624.

    Article  MathSciNet  Google Scholar 

  5. Song G, Li Y: Cross-layer optimization for OFDM wireless networks - part II: algorithm development. IEEE Transactions on Wireless Communications 2005,4(2):625–634.

    Article  MathSciNet  Google Scholar 

  6. Seyedi A, Saulnier GJ: A sub-channel selective orthogonal frequency division multiplexing spread spectrum system. Proceedings of IEEE Military Communications Conference (MILCOM '01), October 2001, McLean, Va, USA 2: 1370–1374.

    Google Scholar 

  7. Loyola L, Miki T: An OFDMA/CDMA-based bandwidth resource allocation scheme for future broadband mobile networks. Proceedings of 56th IEEE Vehicular Technology Conference (VTC '02), September 2002, Vancouver, BC, Canada 1: 42–46.

    Chapter  Google Scholar 

  8. Damji N, Le-Ngoc T: Adaptive downlink multi-carrier resource allocation for real-time multimedia traffic in cellular systems. Proceedings of IEEE International Conference on Communications (ICC '04), June 2004, Paris, France 7: 4258–4262.

    Google Scholar 

  9. Kulkarni G, Adlakha S, Srivastava M: Subcarrier allocation and bit loading algorithms for OFDMA-based wireless networks. IEEE Transactions on Mobile Computing 2005,4(6):652–662.

    Article  Google Scholar 

  10. Damji N, Le-Ngoc T: Adaptive BCPM downlink resource allocation strategies for multiuser OFDM in cellular systems. Proceedings of the 2nd International Conference on Broadband Networks (BROADNETS '05), October 2005, Boston, Mass, USA

    Google Scholar 

  11. TR 101 112 V3.2.0 (1998–04) : Universal Mobile Telecommunications System (UMTS); Selection procedures for the choice of radio transmission technologies of the UMTS. ETSI, 1998

  12. Prasad R, Arnbak JC: Effects of Rayleigh fading on packet radio channels with shadowing. Proceedings of 4th IEEE Region 10 International Conference (TENCON '89), November 1989, Bombay, India 546–548.

    Chapter  Google Scholar 

  13. Amindavar H, Ritcey JA: Padé approximations of probability density functions. IEEE Transactions on Aerospace and Electronic Systems 1994,30(2):416–424. 10.1109/7.272264

    Article  Google Scholar 

  14. Schwartz SC, Yeh YS: On the distribution function and moments of power sums with log-normal components. The Bell System Technical Journal 1982,61(7, part 1):1441–1462.

    Article  MATH  Google Scholar 

  15. Vishwanath S, Goldsmith A: Adaptive turbo-coded modulation for flat-fading channels. IEEE Transactions on Communications 2003,51(6):964–972. 10.1109/TCOMM.2003.813180

    Article  Google Scholar 

  16. Kim I, Lee HL, Kim B, Lee YH: On the use of linear programming for dynamic subchannel and bit allocation in multiuser OFDM. Proceedings of IEEE Global Telecommunications Conference, November 2001, San Antonio, Tex, USA 6: 3648–3652.

    Google Scholar 

  17. Kivanc D, Li G, Liu H: Computationally efficient bandwidth allocation and power control for OFDMA. IEEE Transactions on Wireless Communications 2003,2(6):1150–1158. 10.1109/TWC.2003.819016

    Article  Google Scholar 

  18. Wong CY, Tsui CY, Cheng RS, Letaief KB: A real-time sub-carrier allocation scheme for multiple access downlink OFDM transmission. Proceedings of IEEE Vehicular Technology Conference (VTC '99), September 1999, Amsterdam, The Netherlands

    Google Scholar 

  19. Hugh-Hartogs D: Ensemble modem structure for imperfect transmission media. U.S. Patents Nos. 4679227, July 1987; 4731816, March 1988; and 4833796, May 1989

    Google Scholar 

  20. Stüber GL: Principles of Mobile Communication. Kluwer Academic, Boston, Mass, USA; 1996.

    Book  Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to Tho Le-Ngoc.

Rights and permissions

Open Access This article is distributed under the terms of the Creative Commons Attribution 2.0 International License ( ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Reprints and permissions

About this article

Cite this article

Damji, N., Le-Ngoc, T. Adaptive Downlink Resource Allocation Strategies for Real-Time Data Services in OFDM Cellular Systems. J Wireless Com Network 2006, 017526 (2006).

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • DOI: