Performance of variable bit rate wireless communication systems over Nakagami fading channels

Currently, several wireless standards, both for voice and data communications as well as wireless local area networks, achieve a variable bit rate by different combinations of either binary or non-binary modulation and convolutional codes having different code rates. The probability of bit error for the different combinations of modulation type and code rate utilized by the IEEE 802.11a wireless local area network standard is examined. The channel is modeled as a frequency-selective, slow, Nakagami fading channel with additive white Gaussian noise. Contrary to expectations, for the combinations of modulation type and code rate utilized by the IEEE 802.11a standard, some of the higher data rate combinations outperform some of the lower data rate combinations.