A varying-bandwidth list scheduling heuristic for file transfers

Time-Division Multiplexing/Frequency-Division Multiplexing (TDM/FDM) schemes are typically used in a fixed-bandwidth allocation mode, which means a call is assigned a fixed amount of bandwidth for its whole duration. For file transfers, such schemes compare unfavorably against statistical multiplexing schemes such as packet switching. This is because in fixed-bandwidth TDM/FDM schemes, once a file transfer is allocated a certain bandwidth, it cannot take advantage of bandwidth that becomes available as a result of other transfers completing. In this paper, we propose a Varying-Bandwidth List Scheduling (VBLS) heuristic for TDM/FDM networks in which a sender specifies the file size, maximum bandwidth limit and a desired start time, and the network returns a time-range-capacity allocation vector assigning varying bandwidth levels in different time ranges for the transfer. Simulation results show that VBLS performance is indistinguishable from packet-switching performance, and hence superior to the fixed-bandwidth allocation mode.