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Throughput Enhancement and Performance Improvement of the OFDM Based WLAN System


Ibrahim Ismail Al-kebsi, Mahamod Ismail, Kasmiran Jumari, T. A. Rahman


Vol. 9  No. 4  pp. 138-148


This paper presents two models of WLAN-OFDM, which offer a new decision policy in the adaptive modulation (AM) technique of choosing the order of modulation schemes to map the data onto the carriers. Numerous modes will be tested in this paper. The common concept in these proposed models is using the high order modulation schemes together with the low order ones at low SNR values. In model (1), the percentage of using the different modulation schemes will be controlled by the SER value only. So the SER performance of the high order modulation schemes such as 128, 256QAM will be improved. However in model (2), decision policy of choosing the modulation scheme will be made based on the SNR value, but the percentage of the usage will be controlled by the SER value. In both models the appropriate choosing of the clipping ratio (CR) is very important to define the percentage of using a certain order of modulation scheme. The throughput of the two tested models will be enhanced dramatically at all SNR values, and a good improvement in the PAPR will be achieved.


PAPR, clipping ratio, Adaptive modulation, IEEE 802.11g, OFDM, SER