Wireless Infidelity I - War Driving

General aspects:

The concept of wireless networking dates back at least as far as ALOHANET in 1970. ALOHAnet, also known as ALOHA, was a pioneering computer networking system developed at the University of Hawaii. It was first deployed in 1970, and while the network itself is no longer used, one of the core concepts in the network is the basis for the widely used Ethernet. One of the early computer networking designs, the ALOHA network was created at the University of Hawaii in 1970 under the leadership of Norman Abramson and others (including N. Gaarder and N. Weldon). The idea was to use low-cost amateur radio-like systems to create a computer network linking the far-flung campuses of the University. The original version of ALOHA used two distinct frequencies in a hub/star configuration, with the hub machine broadcasting packets to everyone on the "outbound" channel, and the various client machines sending data to the hub on the "inbound" channel. Data received was immediately re-sent, allowing clients to determine whether or not their data had been received properly. Any machine noticing corrupted data would wait a short time and then re-send the packet. This mechanism was also used to detect and correct for "collisions" created when two client machines both attempted to send a packet at the same time.

Like the ARPANET group, ALOHA was important because it used a shared medium for transmission. This revealed the need for more modern medium access control schemes such as CSMA/CD, used by Ethernet. Unlike the ARPANET where each node could only talk to a node on the other end of the wire, in ALOHA all nodes were communicating on the same frequency. This meant that some sort of system was needed to control who could talk at what time. ALOHA's situation was similar to issues faced by Ethernet (non-switched) and Wi-Fi networks.

This shared transmission medium system generated interest by others. ALOHA's scheme was very simple. Because data was sent via a teletype the data rate usually did not go beyond 80 characters per second. When two stations tried to talk at the same time, both transmissions were garbled. Then data had to be manually resent. ALOHA proved that it was possible to have a useful network without solving this problem, and this sparked interest in others, most significantly Bob Metcalfe and other researchers working at Xerox PARC. This team went on to create the Ethernet protocol.ALOHA is the precursor of the first generation of wireless networks.

Wireless technologies may be categorized by their function, frequencies, bandwidth, communication protocols involved and so on. For our purposes we will categorize them as:

1) Wireless Data Networks (WDNs)

2) Personal Area Networks (PANs)

3) Wireless Local Area Network (WLANs)

- Wireless Metropolitan Area Networks (WMANs)

- Wireless Wide Area Networks (WWANs)

WDN is related to develop for and marketed by vendors in the telephony and handheld market (for basic digital cellular phones to PDAs and tablet PCs). It includes protocols such as:

- Cellular Digital Packet Data (CDPD) an older 19.2 kbps wireless technology that is still in use in some police departments for communicating with patrol cars

- General Packet Radio Service (GPRS)

- Code Division Multiple Access 2000 (CDMA 2000) multi-user combined voice and data 2.5 generation technologies that exceed 100 kbps

- Wireless Application Protocol (WAP) provides wireless support of the TCP/IP protocol suite and now provides native support of HTTP and HTML. This application is used by anybody who has a cellular phone.

PANs began as a “workspace networks”. For example let’s take Bluetooth which is a desktop mobility PAN that was designed to support cable-free communication between computers and peripherals.

Blackberry integrates telephony, Web browsing , email and messaging services with PDA productivity applications. As such it blurs the distinction between PAN and WLAN.

WLAN is what most of us think as wireless technology. It includes the 802.11 family of protocols (introduced in 1997). In 2001 Texas Instruments proposed a 22Mbps variation of 802.11b called “b+” and Atheros proposed a 108 Mbps variant of 802.11g called “Super G”.