Technology-Independent Link Sensing in Wireless Ad-Hoc Networks: Benefits and Challenges

Wireless-connected computing and communication devices such as cell phones, pagers, hand-held PCs, and the latest “integrated” devices that incorporate a PC or PDA and a cell phone into one package are becoming increasingly more popular. Some of these devices have several network interface options, such as BluetoothBluetooth is a short-range («10m range) wireless network technology primarily designed to replace short-distance cable connections. See http://www.bluetooth.com for more information.The IEEE 802.11 standard was ratified in 1997 and specifies physical layer and medium- access layer behavior for wireless Local Area Networks. The 802.11HR standard is an amendment to the 802.11 standard to include higher data rates [13].2.5G cellular networks are upgrades to the GSM cellular standard to provide higher data ransfer rates. See http://www.gsmworld.com/technology/gprs/index.shtml for more information. The 3G or Third Generation wireless standards are part of the IMT-2000 standard of the International Telecommunications Union. Devices conforming to this standard will support data rates up to 2Mbps and are expected to be available in the US as early as 2003. See http://www.imt-2000.org/portal/index.asp for more information.(GSM or GPRS-enabled) cellular service. As the devices become more sophisticated, it will be possible to automatically switch among the network interfaces, even within the same communication. For a device with multiple nerwork interfaces, it would be useful to have a single method of determining thi link status for each of those interfaces. With this ability, a user or an operating system could then choose the best available interface to use for communication. It would also be useful to have a means of predicting link failures before the link actually fails. Then the device would have ability to handoff transmission among the interfaces without disruption of the ongoing communication. In th event thore is only a single interface with a useable link, means of predicting that link’s failure would allow the operating sustem or user to take some other appropriate action, such as sending an “about to be disconnected” message to the distand end, or adjusting position to obtain a better link quality.