Multi-rate transmissions in infrastructure wireless LAN based on IEEE 802.11b protocol

We discuss the issues of providing multiple data rates (1/2/5.5/11 Mbps) over an IEEE 802-11 infrastructure wireless network. With the characteristic of modulation schemes, the data rate of the wireless network is inversely proportional with the transmission distance. A moving mobile station needs to dynamically adjust the modulation scheme to keep the connection alive and to achieve the maximum network throughput. To do this, the mobile stations are requested to detect the distance between access point and itself from time to time. A simple broadcasting approach is proposed for mobile stations to detect their locations in the wireless network. Based on this information, the mobile node can easily determine the proper transmission rate