Packet radio
Packet radio is the name for datagram data network technology which sends data through the air using electro-magnetic radiation (i.e. radio). Packet radio technologies such as Wi-Fi and cellular telephone are now almost ubiquitous as the 'last hop' in most things' connection to the Internet, both to allow mobility, and to avoid the hassle of having to run a physical conductor to the unit.
As such, most packet radio technologies are technically LANs. Since most packet radio networks have more than one station trying to transmit on a given radio frequency, an access control mechanism must be provided; at first, CSMA-CD was invented for this.
History
The first packet radio system built was the ALOHA System, built in Hawaii to connect together University of Hawaii campuses on different islands; because of the distances involved, this was technically a wide area network.
The success of the ALOHA network inspired DARPA to start a fairly considerable packet radio project, the Packet Radio Network, in 1973, to explore the possibility of an ad-hoc data network using wireless links.
Further reading
- Robert E. Kahn, Steven A. Gronemeyer, Jerry Burchfiel, Ronald C. Kunzelman, Advances in Packet Radio Technology, Proceedings of the IEEE (Volume: 66, Issue: 11, Nov. 1978), pp. 1468-1496 (online precis available here)
