Fair Scheduling and Medium Access in Wireless Packet Networks

 

 

A wireless shared channel network packet communication method emulates fluid flow fair scheduling. Errors inherent in wireless communication and unaccounted for in fair scheduling for wired networks are accounted for according to the method. Lagging communication flows, typically caused by burst errors in wireless communication systems, make up for their lag by causing leading flows to give up their lead. The method is independent of the pattern of channel error. In a preferred embodiment, lag compensation is accounted for by a service tag which identifies a precedence for contention based upon the previous denial of access for channel error. This precedence allows compensation when channels become error free. A modified preferred embodiment first attempts intraframe compensation by swapping slots when a host predicts an error for its assigned slot and another host assigned a later slot is able to transmit in the slot. Interframe compensation, when needed, is accomplished preferably by a round robin contention among backlogged flows. Errors are predicted by hosts for a subsequent slot when activity is sensed in a current slot but no good packet is received. Preferred packet structures include data and control slots, with data slots partitioned to provide necessary error status and backlog information piggybacked with data so a base has sufficient information to implement compensation in contention resolution.