A method for scheduling a random-access communication system having high-priority (HP) and low-priority (LP) nodes is provided, where the scheduling is configured such that the system provides an absolute throughput guarantee for the HP nodes, and a proportional throughput guarantee for the LP nodes. The method is based on obtaining a length of a contention window assigned to an individual node, which is either a HP or a LP node, from a per-slot attempt rate of this individual node. In particular, the attempt rate of each individual node is determined by an algorithm configured such that a resultant sum of the per-slot attempt rates of all the individual nodes is a fixed value independent of the number of the individual nodes. By this scheduling method, the maximum system throughput is approached. The method can be advantageously used in a wireless local area network (WLAN).