| abstract |
The present invention relates to a technique for dynamic scheduling of integrated circuit- and packet-switching in accordance with rapidly changing demand in a multibeam satellite switched, time division multiple accessed (SS/TDMA) environment. It is equally applicable to terrestrial communication systems, or more broadly to any type of centralized scheduling system involving arbitration of contention for resources among a plurality of users or equipments. All of the scheduling is performed onboard the satellite by a scheduler (6, 8) under the direction of a controller (4). The controller contains all the information related to both circuit requests ([cij]) and packet requests ([pij]) in matrix form, where it constructs these matrices from requests for service from each zone to each zone on a frame-by-frame or possibly less frequent basis, which it receives from the ground via an order-wire facility. The scheduler performs, for each of the slots of a frame, a least-choice assignment of the circuit requests contained in the controller. The scheduler then applies the same least-choice procedure to assign packets to switch positions not already assigned to the circuit traffic. The least-choice assignment yields efficient bandwidth and transponder utilization. Provision is also made for prioritizing or preempting both the circuit and packet traffic employing a movable-boundary or other protocols. At the completion of both the circuit and packet assignments for a particular slot, the controller broadcasts the slot schedule to the earth stations. |