Non-iterative Bit Loading Algorithm for OFDM in Independent and Correlated fading

  • Manry, John W. (Naval Air Systems Command) ;
  • Nagaraj, Santosh (Department of Electrical and Computer Engineering, San Diego State University)
  • Received : 2013.04.19
  • Accepted : 2013.11.17
  • Published : 2014.06.30


This paper will focus on improving the performance of orthogonal frequency division multiplexing (OFDM) in Rayleigh fading environments. The proposed technique will use a previously published method that has been shown to improve OFDM performance in independent fading, based on ordered sub-carrier selection. Then, a simple non-iterative method for finding the optimal bit-loading allocation was proposed. It was also based on ordered sub-carrier selection. We compared both of these algorithms to an optimal bit-loading solution to determine their effectiveness in a correlated fading environment. The correlated fading was simulated using the JTC channel models. Our intent was not to create an optimal solution, but to create a low complexity solution that can be used in a wireless environment in which the channel conditions change rapidly and that require a simple algorithm for fast bit loading.


  1. IEEE Standard for Local and Metropolitan Area Networks, IEEE Standard 802.16e, 2005.
  2. IEEE Standard for Information Technology-Telecommunications and Information Exchange Between Systems-Local and Metropolitan Area Networks, IEEE Standard 802.11g, 2003.
  3. C. L. Holloway, M. G. Cotton, and P. McKenna, "A simplified model for predicting the power delay profile characteristics of an indoor radio propagation channel," Institute for Telecommunication Sciences, Boulder, CO, NTIA Technical Report TR-98-353, August 1998.
  4. T. R. Rao and A. Giulietti, "A performance study on the 802.11g WLAN OFDM system," in The International Conference on Computer as a Tool, Belgrade, Serbia and Montenegro, 2005, pp. 128-130.
  5. J. A. C. Bingham, "Multicarrier modulation for data transmission: an idea whose time has come," IEEE Communications Magazine, vol. 28, no. 5, pp. 5-14, 1990.
  6. D. Dardari, "Ordered subcarrier selection algorithm for OFDM-based high-speed WLANs," IEEE Transactions on Wireless Communications, vol. 3, no. 5, pp. 1452-1458, 2004.
  7. B. Sklar, Digital Communications: Fundamentals and Applications, 2nd ed. Upper Saddle River, NJ: Prentice-Hall PTR, 2001.
  8. Deployment/Testing Ad Hoc Group, Joint Technical Committee (AIR) Standards Contribution, September 1994. Joint Technical Committee (Air) Standards Contribution, "Technical report on RF channel characterization and system deployment modeling," JTC (Air) Standards Contribution, Technical Report JTC(AIR)/94.09.23-065R6, September 1994.
  9. D. S. Kim, S. H. Kim, C. S. Kim, and M. M. Lee, "Performance analysis of OFDM system based on IEEE 802.11a," in Proceedings of the International Technical Conference on Circuits, Systems, Computers and Communications, Phuket, Thailand, 2002.