US 2002/0154653 A1 · Random medium access methods with backoff adaptation to traffic

Abstract

Using low PF values in conjunction with traffic-adapted contention windows leads to substantial decreases in delay and jitter. In general, adaptation to traffic reduces contention or delay: opening up the contention window in congestion and closing it on relief. Residual backoff adaptation provides for the reduction of the already decremented backoff values of stations that interrupted the backoff countdown process due to a transmission. It is good to adapt both the contention window and the residual backoff in order to avoid jitter. Otherwise, if the contention window is reduced but residual backoffs stay unchanged, new arrivals will enjoy shorter backoff delays than older ones, resulting in greater jitter. Adjusting both preserves the relative ordering of backoff counter values, which implies also some form of age ordering. Different adjustments can be applied to different priority traffic.

Claims97

Dependent claims

A method for a distributed medium access protocol that schedules transmission of different types of packets on a channel based on a service quality specification for each type of packet, comprising the steps of:

determining at a plurality of nodes in the access network, an urgency class of pending packets according to a scheduling algorithm;
transmitting pending packets in a given urgency class before transmitting packets of a lower urgency class;
remembering the number of transmission attempts by a node for the last transmission of same node;
estimating from said number of transmission attempts the current congestion experienced;
and
adjusting a backoff counter to current congestion levels to provide a dispersion of packet traffic bursts.

3 more elements

Dependencies are inferred from the claim text.

Random medium access methods with backoff adaptation to traffic

Life of this patent

Random medium access methods with backoff adaptation to traffic

Life of this patent

Abstract

Claims97