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.

The medium used by indoor wireless LANs is a shared, scarce resource. Hence, efficient use of this medium is important, which in turn requires an efficient MAC protocol. Moreover, next generation wireless LANs will have to support data rates from 10 to 100 Mbits/s. At these data rates, turnaround times in half-duplex radios are a large overhead. This makes the current wireless standards inefficient. However, busy-tone solutions can get around this problem. In spite of their better performance, the busy-tone protocols are not widely used because of the hardware cost, i.e., the requirement of two transceivers-one each for the data and feedback channel. A novel wireless transceiver architecture which mitigates this hardware cost by overlaying the data channel and the feedback channel in the same frequency band is designed. It is shown that this transceiver can be built with current technology. Based on this wireless transceiver, a new MAC protocol called wireless collision detect (WCD) is proposed. This protocol uses a carrier detect signal to decrease the collision probability and receiver initiated feedback to handle hidden nodes. We derive a mathematical expression for the throughput of the protocol. The simulation results match the analysis. At 100 Mbits/s, WCD achieves 77% efficiency with 192 byte packets. For this scenario, the throughput of the IEEE 802.11 MAC protocol and RI-BTMA is 3% and 52%, respectively.

Wireless technology is an attractive option to network devices in the home as it does not require rewiring the home. The media access protocol (MAC) plays a crucial role in allowing multiple devices to transmit and receive on the shared wireless medium and thereby determining the efficiency of a wireless home network (WiHN). It is found that many of the protocols proposed to date like the Distributed Foundation Wireless MAC (DFWMAC) in the IEEE 802.11 standard have poor performance at high data rates (100 Mbps). We modify the slotted-idle sense multiple access protocol and propose a simple and efficient MAC protocol which fits well with the WiHN architecture. We present a queuing analysis and simulation results of the performance of the wireless home network MAC (WiHNMAC) protocol.