A scheduling algorithm for transporting variable rate coded voice in bluetooth networks

In the current Bluetooth specification voice traffic is transmitted using synchronous connection-oriented (SCO) links. Only uncompressed voice connections with Pulse Code Modulation (PCM) are supported, and 64Kbps bandwidth is assigned to each voice connection. However, with the use of speech coding techniques that produce compressed voice and/or detect silent periods, it is expected that high quality voice data can be transmitted at or below 4Kbps, and that the Bluetooth specification will support voice transmission at two or more distinct rates. A key issue that should be resolved in order to support variable rate coded voice transmission in Bluetooth is how to meet the temporal service requirements of various variable rate coded voices.In this paper, we propose, in compliance with the Bluetooth specification, a distance constrained scheduling (DCS)-based, intra-piconet scheduling algorithm to support admission control and scheduling of variable rate coded voice traffic, with the objective of providing the temporal quality of service requirement of each master-slave pair. Further, in the case that requests to establish voice connections exceed the system capacity, we present two admission control algorithms that select, based on utility functions defined, optimal subsets from an otherwise unschedulable request set. We also conduct simulations to evaluate the performance of the proposed algorithms in terms of schedulability, capability of delay jitter control, and effectiveness of admission control.