Browse Prior Art Database

Virtual Multiple Access Method

IP.com Disclosure Number: IPCOM000087446D
Original Publication Date: 1977-Jan-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Rothauser, E: AUTHOR [+2]

Abstract

In a system where a large number of terminals use a single communication channel and information is transmitted in the form of packets in cyclic frames, a special signalling channel is provided in addition to the packet transmission channel. The signalling channel is subdivided into a request time slot (RTS) for requesting the packet transmission channel by terminals, and a scheduling time slot (STS) for allocating it to terminals by a central station.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Virtual Multiple Access Method

In a system where a large number of terminals use a single communication channel and information is transmitted in the form of packets in cyclic frames, a special signalling channel is provided in addition to the packet transmission channel. The signalling channel is subdivided into a request time slot (RTS) for requesting the packet transmission channel by terminals, and a scheduling time slot (STS) for allocating it to terminals by a central station.

Virtual channel addresses, which are temporarily assigned, are used for requesting and scheduling. Each virtual address used is the time t(i) (with respect to frame cycle start) when a respective terminal gets ready to send. The request channel contains n bit positions which represent n possible discrete request times t(1)...t(n) (or "virtual addresses") within each cycle. For requesting service, a terminal sets, in the next frame, the respective one of the request channel bits to "1", which corresponds to its "get-ready" time for transmission.

Several requests may be overlapped in one cycle as indicated by t(i), t(j), t(k) in the drawing. The central station selects one requesting terminal by any given algorithm and sets the respective virtual address into the scheduling channel of the next frame. Conflicts can be resolved by normal error detection/correction procedures.

1

Page 2 of 2

2

[This page contains 2 pictures or other non-text objects]