PHY and MAC Performance Evaluation of IEEE 802.11a WLAN over Fading Channels

Abstract

This paper presents an overview of physical (PHY) and medium access control (MAC) layers for IEEE 802.11a, which is a standard of a broadband high-speed wireless local area network (WLAN). IEEE 802.11a uses 5 GHz frequency band and its PHY is based on orthogonal frequency division multiplexing (OFDM). In this paper, we evaluate the OFDM-based PHY and MAC performance of IEEE 802.11a under various practical wideband channel models, which are abstracted from actual propagation measurements. The effects of different transmission modes defined in PHY on the IEEE 802.11 system performance are investigated. We also discuss the impact of link adaptation, which attempts to choose the best-suited transmission mode according to channel conditions, on the overall system performance.

Indexing terms:

• OFDM
• IEEE 802.11a
• HYPERLAN/2
• IFFT
• Convolutional coding
• Time dispersive
• Frequency selective
• Wideband
• Rayleigh fading
• MAC
• Link Adaptation