Transmitter Based Capacity Enhancement with Cross-Layer Design Approach for IEEE 802.11 Ad-hoc Networks

We propose the Transmitter Based Capacity Enhancement Algorithm for Wireless Ad-hoc Networks using Cross-Layer Design Approach (TCECLD) by dynamically adapting the data rate. The proposed algorithm uses the attributes of Auto-Rate Fallback (ARF) [1] and Receiver Based Auto-Rate (RBAR) [2] control mechanisms with additional practical features to facilitate multipath fading. Like ARF, Acknowledgement (ACK) feedback count is used along with received signal strength for dynamic rate selection. Unlike RBAR, no modification of the Medium Access Control (MAC) frame format is necessary for feedback control since the channel state information is conveyed through Cross-Layer interface. The mechanisms are described to implement the proposal on top of the existing Auto-Rate adaptation scheme in a nearly IEEE 802.11 compliant manner. We also analytically study and characterize the gains in throughput as a function of the channel conditions. Finally an extensive set of simulations are performed on IEEE 802.11b media access protocols to observe the system throughput.