SIMSCRIPT Solutions


Telecommmunications


Aloha Packet Radio Network

The City College of New York, Electrical Engineering Dept.; New York, NY

The Aloha access scheme is a multi-user channel access scheme. It is a probabilistic scheme that leads, in some instances, to packets overlapping. Any user (or station) that has a packet to send, say to a central station database, transmits it immediately over a radio channel. If two or more users decide to transmit within a packet-time, overlapping between the transmitted packets occurs and as a result, the packets are destroyed and have to be re-transmitted at a random time. This program simulates and animates the performance of the Aloha Network.

The SIMSCRIPT II.5 program consists of a number of processes. The USER process models packet arrival (generation) to the user station. Another process called PACKET models packet transmission. A resource called CHANNEL models the packets waiting in the buffer. We use the routine READ.DAT to input data; use routine MENU to select parameters; and use INITIALIZE.GRAPHICS to initialize graphics display.

Alternatives Considered: None