Several users, with different traffic types, share a wireless channel, and a scheduler is used to assign the order in which they are served. The overall capacity of the channel is limited by the total transmission power that is available. One possibility is for the scheduler to order the traffic by taking into account the throughput for each traffic type, together with a set of associated ‘credit functions’, which depend also on the corresponding channel quality. The Study Group was asked to consider the performance of this scheduler and how the queuing time and packet loss depend on the capacity of the system and the parameters that occur in defining throughput, credit and channel quality. An explicit version of the model was constructed and analysed, from which it can be seen how to choose the parameters so that the scheduler has the desired behaviour.

Problem presented by
José Gil, Motorola

Study Group contributors
David Allwright (Industrial Mathematics KTN)
Tristram Armour (Industrial Mathematics KTN)
Vera Hazelwood (Industrial Mathematics KTN)
Robert Leese (Industrial Mathematics KTN)
Steve Noble (Brunel University)
Ida Pu (Goldsmiths College London)