ALOHAnet

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ALOHAnet, also known as the ALOHA System[1][2], or simply ALOHA, was a pioneering computer networking system developed at the University of Hawaii[3]. ALOHAnet became operational in June, 1971, providing the first demonstration of a wireless data network[4].

The ALOHAnet used a new method of medium access (ALOHA random access) and experimental UHF frequencies for its operation, since frequency assignments for communications to and from a computer were not available for commercial applications in the 1970s. But even before such frequencies were assigned there were two other media available for the application of an ALOHA channel – cables and satellites. In the 1970s ALOHA random access was employed in the widely used Ethernet cable based network[5] and then in the Marisat (now Inmarsat) satellite network[6].

In the early 1980s frequencies for mobile networks became available, and in 1985 frequencies suitable for what became known as WiFi were allocated in the US. These regulatory developments made it possible to use the ALOHA random access techniques in both WiFi and in mobile telephone networks.

ALOHA channels were used in a limited way in the 1980s in 1G mobile phones for signaling and control purposes[7]. In the 1990s, Matti Makkonen and others at Telecom Finland greatly expanded the use of ALOHA channels in order to implement SMS message texting in 2G mobile phones. In the early 2000s additional ALOHA channels were added to 2.5G and 3G mobile phones with the widespread introduction of GPRS, using a slotted ALOHA random access channel combined with a version of the Reservation ALOHA scheme first analyzed by a group at BBN[8].

Contents

Overview

One of the early computer networking designs, development of the ALOHA network was begun in 1968 at the University of Hawaii under the leadership of Norman Abramson and others (including F. Kuo, N. Gaarder and N. Weldon). The goal was to use low-cost commercial radio equipment to connect users on Oahu and the other Hawaiian islands with a central time-sharing computer on the main Oahu campus.

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