Channel access system
AssigneeFuji Xerox Co., Ltd.
InventorHiroshi Kume
Life of this patent
Estimating the term…
Abstract
In order to increase the speed at which a determination is made as to which of a number of competing stations will occupy a particular block, the blocks are divided into a plurality of time slots and the various stations transmit probe signals into the time slots. Each station transmits its probe signal with a particular probability, with the probabilities preferably differing between respective stations. The number of occupied blocks in each frame can be counted to determine a degree of congestion, and the probe signal probabilities can be adjusted in accordance with the degree of congestion. Also if the degree of congestion is low, stations can transmit their packet signals directly without first transmitting probe signals, and the probe signal procedure will be followed thereafter only if a packet collision occurs.
Claims23
A channel access system in a communication network of the type wherein a plurality of stations communicate with one another over a communication medium and wherein data signals on said medium are grouped into frames periodically occurring on a time axis, with each frame comprising a plurality of successively occurring blocks, each station including packet transmitting means for transmitting packet signals onto said medium to occupy a previously unoccupied block, whereby multiplexed digital signals are transmitted on said medium in a time division manner, said channel access system comprising:
- means for dividing a first block into a plurality of time slots;
- probe signal transmitting means at a particular station for transmitting a probe signal in one of said time slots when said particular station desires to transmit a packet signal in said first block;
- and
- monitoring means for monitoring said one time slot to count the number of probe signals occurring in said time slot and to determine if more than one probe signal occurs in said one time slot, whereby said particular station is given occupation of said first block in accordance with the number of probe signals counted in said one time slot.
Dependencies are inferred from the claim text.