Wireless collision detect (WCD): multiple access with receiver initiated feedback and carrier detect signal

An ad-hoc wireless network is a collection of wireless nodes that can communicate with each other without the aid of any pre-existing communication infrastructure. The medium access control protocol plays a crucial role in such networks by enabling efficient communication among multiple devices on the shared medium. At high data rates, busy-tone protocols will be much more efficient than collision avoidance protocols because of transceiver turn-around times. Wireless collision detect (WCD) is proposed to enhance the performance of existing busy-tone solutions. This improves the performance and eliminates hidden and exposed nodes. This protocol is based on collision detection by the destination node (DN) and performs similarly to the Ethernet protocol. We analyze the protocol and get very close agreement between analytical and simulation results. At 100 Mbps, WCD achieves 77% efficiency even with packets as short as 192 bytes which is a 10 fold improvement over the IEEE 802.11 MAC protocol. When the time during which the node is vulnerable to a collision is three times the time to detect a carrier, WCD performs 20% better than RI-BTMA