Fading Effects on the Lower Shifting of Mode Switching Thresholds in the Rate Adaptive IEEE 802.11a/g WLANs
Chie Dou, Li-Shin Wang
DOI: 10.4236/ijcns.2010.38088   PDF    HTML     4,357 Downloads   7,821 Views   Citations


In this paper we used the probability distribution of the average channel gain of the fading channel to analyze the degree of fading effects on both the PER (packet error rate) and the throughput in OFDM systems. Instead of solely examining the average received SNR (signal-to-noise ratio) value of a packet, considering the whole distribution of the average received SNR allows us to aggregate a better selection of the mode switching thresholds in the rate adaptive 802.11 a/g WLAN. This paper demonstrates that the set of mode switching thresholds can be determined for each individual target , so that the optimal throughput performance is obtained on a per target basis. Numerical results show that mode switching thresholds should be reduced with the lowering of target values. This conclusion could have significant implications for improving the performances of location (distance)-dependent mobile applications, since the determinations of target values are closely related to the distances between mobile devices and the access point.

Share and Cite:

C. Dou and L. Wang, "Fading Effects on the Lower Shifting of Mode Switching Thresholds in the Rate Adaptive IEEE 802.11a/g WLANs," International Journal of Communications, Network and System Sciences, Vol. 3 No. 8, 2010, pp. 655-667. doi: 10.4236/ijcns.2010.38088.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] IEEE Standard 802.11a, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: High-speed Physical Layer in the 5GHz Band, Supplement to the IEEE 802.11 Standard, September 1999.
[2] O. Awoniyi and F. A. Tobagi, “Packet Error Rate in OFDM-Based Wireless LANs Operating in Frequency Selective Channels,” Proceedings of 25th IEEE International Conference on Computer Communications, Barcelona, 23-29 April 2006, pp. 1-13.
[3] J. Armstrong, “Analysis of New and Existing Methods of Reducing Intercarrier Interference Due to Carrier Frequ- ency Offset in OFDM,” IEEE Transactions on Communications, Vol. 47, No. 3, March 1999, pp. 365-369.
[4] W. Zhang and J. Lindner, “SINR Analysis for OFDMA Systems with Carrier Frequency Offset,” Proceedings of 18th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, Athens, 3-7 September 2007, pp. 1-5.
[5] Q. Yang, F. Fu, Y. Wu and K. S. Kwak, “Sub-Optimum Superimposed Training Design for Estimating of Mobile OFDM Channels,” Proceedings of 4th International Conference on Communications and Networking in China, Xi’an, 26-28 August 2009, pp. 1-5.
[6] M. Lampe, H. Rohling and W. Zirwas, “Misunderstandings about Link Adaptation for Frequency Selective Fading Channels,” Proceedings of 13th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications, Lisbon, Vol. 2, 15-18 September 2002, pp. 710-714.
[7] M. Lampe, T. Giebel, H. Rohling and W. Zirwas, “PER- Prediction for PHY Mode Selection in OFDM Communication Systems,” Proceedings of IEEE Global Telecommunications Conference, San Francisco, Vol. 1, 1-5 December 2003, pp. 25-29.
[8] C. Snow, L. Lampe and R. Schober, “Error Rate Analysis for Coded Multicarrier Systems over Qusai-Static Fa- ding Channels,” IEEE Transactions on Communications, Vol. 55, No. 9, September 2007, pp. 1736-1746.
[9] H. Gong, W. Ye, S. Feng and H. Song, “A Subcarrier Al- location Algorithm for Efficiently Reducing Power in Multiuser OFDM Systems,” Wireless Personal Communications, Vol. 40, No. 2, 2007, pp. 233-243.
[10] J. Medbo and P. Schramm, “Channel Models for HIPE- RLAN/2,” ETSI/BRAN Document Number 3ERI085B, 1998.
[11] D. Qiao, S. Choi and K. G. Shin, “Goodput Analysis and Link Adaptation for IEEE 802.11a Wireless LANs,” IEEE Transactions on Mobile Computing, Vol. 1, No. 4, October 2002, pp. 278-292.
[12] S. Armour, A. Doufexi, A. Nix and D. Bull, “A Study of the Impact of Frequency Selectivity on Link Adaptive Wireless LAN Systems,” Proceedings of 56th IEEE Vehicular Technology Conference, Vancouver, Vol. 2, 24-28 September 2002, pp. 738-742.
[13] L. B. Le, E. Hossain and M. Zorzi, “Queueing Analysis for GBN and SR ARQ Protocols under Dynamic Radio Link Adaptation with Non-Zero Feedback Delay,” IEEE Transactions on Wireless Communications, Vol. 6, No. 9, September 2007, pp. 3418-3428.
[14] B. O’Hara and A. Petrick, “IEEE 802.11 Handbook–A Designer’s Companion,” IEEE Press, Hoboken, 1999.
[15] M. R. Raghavendra, S. Bhashyam and K. Giridhar, “Fast Multipath Delay Estimation in OFDM Systems Using Frequency Swept Pilots,” Proceedings of 9th International OFDM Workshop, Dresden, 15-16 September 2004, pp. 237-240.
[16] N.-L. Hung, L.-N. Tho and C. C. Ko, “Joint Channel Estimation and Synchronization with Inter-Carrier Interference Reduction for OFDM,” Proceedings of IEEE International Conference on Communications, Glasgow, 24- 28 June 2007, pp. 2841-2846.
[17] J. Tao, J. Wu and C. Xiao, “Channel Estimation for OFDM Systems in the Presence of Carrier Frequency Offset and Phase Noise,” Proceedings of IEEE International Conference on Communications, Beijing, 19-23 May 2008, pp. 5072-5076.
[18] H. Kang, W. Hwang and K. Kim, “OFDM Systems with Subchannel Power Control under the Two-Ray Multipath Channel,” Proceedings of IEEE International Conference on Communications, Helsinki, Vol. 6, 11-14 June 2001, pp. 1856-1860.
[19] M. S. Bahaei, “Joint Optimization of Transmission Rate and Outer-Loop SNR Target Adaptation over Fading Cha- nnels,” IEEE Transactions on Communications, Vol. 55, No. 3, March 2007, pp. 398-403.
[20] S. Haykin, “Communication Systems,” 4th Edition, John Wiley & Sons, Hoboken, 2001.
[21] M. B. Pursley and D. J. Taipale, “Error Probabilities for Spread-Spectrum Packet Radio with Convolutional Codes and Viterbi Decoding,” IEEE Transactions on Communications, Vol. 35, No. 1, January 1987, pp. 1-12.
[22] D. Haccoun and G. Begin, “High-Rate Punctured Convolutional Codes for Viterbi and Sequential Decoding,” IEEE Transactions on Communications, Vol. 37, No. 11, November 1989, pp. 1113-1125.
[23] K. Haider and H. S. Al-Raweshidy, “Evaluation of User Capacity and Channel Model Effect in HiperLAN/2 System,” Proceedings of 4th International Workshop on Mobile and Wireless Communications Network, Stockholm, 9-11 September 2002, pp. 554-558.
[24] H. Bolcskei and A. J. Paulraj, “Space-Frequency Coded Broadband OFDM Systems,” Proceedings of IEEE Wire- less Communications and Networking Conference, Chicago, Vol. 1, 23-28 September 2000, pp. 1-6.
[25] M. Morelli and U. Mengali, “A Comparison of Pilot- Aided Channel Estimation Methods for OFDM Systems,” IEEE Transactions on Signal Processing, Vol. 49, No. 12, December 2001, pp. 3065-3073.
[26] R. Gruenheid, H. Rohling, J. Ran, E. Bolinth and R. Kern, “Robust Channel Estimation in Wireless LANs for Mobile Environments,” Proceedings of 56th IEEE Vehicular Technology Conference, Vancouver, Vol. 3, 24-28 Septem- ber 2002, pp. 1545-1549.
[27] Z. Yuanjin, “A Novel Channel Estimation and Tracking Method for Wireless OFDM Systems Based on Pilots and Kalman Filtering,” IEEE Transactions on Consumer Elec- tronics, Vol. 49, No. 2, May 2003, pp. 275-283.
[28] A. P. Petropulu, R. Zhang and R. Lin, “Blind OFDM Cha- nnel Estimation through Simple Linear Precoding,” IEEE Transactions on Wireless Communications, Vol. 3, No. 2, March 2004, pp. 647-655.
[29] F. Gao and A. Nallanathan, “Blind Channel Estimation for OFDM Systems via Generalized Precoding,” IEEE Transactions on Vehicular Technology, Vol. 56, No. 3, May 2007, pp. 1155-1164.
[30] F. Gao, Y. Zeng, A. Nallanathan and T. S. Ng, “Robust Subspace Blind Channel Estimation for Cyclic Prefixed MIMO OFDM Systems: Algorithm, Identifiability and Performance Analysis,” IEEE Journal on Selected Areas in Communications, Vol. 26, No. 2, February 2008, pp. 378-388.
[31] H.-W. Kim, C.-H. Lim and D.-S. Han, “Viterbi Decoder Aided Equalization and Sampling Clock Tracking for OFDM WLAN,” Proceedings of 60th IEEE Vehicular Technology Conference, Los Angeles, Vol. 5, 26-29 September 2004, pp. 3738-3742.
[32] W.-C. Liu, L.-C. Wang and Y.-W. Lin, “Physical Layer Effects on the MAC Goodput Performance for the Rate Adaptive IEEE 802.11a/g WLAN,” Proceedings of IEEE Wireless Communications and Networking Conference, Atlanta, Vol. 3, 21-25 March 2004, pp. 1873-1878.

Copyright © 2024 by authors and Scientific Research Publishing Inc.

Creative Commons License

This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License.