MAC scheduling and SAR policies for Bluetooth: a master driven TDD pico-cellular wireless system

Abstract

We propose and study data scheduling and segmentation and reassembly (SAR) policies in Bluetooth. In such systems, the conventional scheduling policies such as round robin perform poorly as they are not suited to the tight coupling of uplink-downlink scheduling and result in slot wastage and unfairness. Scheduling in Bluetooth is complex due to (i) reserved slots for voice traffic, and, (ii) variable sized data packets. The reservation of voice slots at regular intervals results in non-contiguous TDD slots available for data. We propose two new scheduling policies that utilize information about the size of the head-of-the-line (HOL) packet at the master and slave queues to schedule the TDD slots effectively. These policies achieve high throughput and greater fairness compared to the round-robin based scheduling policies. We then study the SAR policies at the Bluetooth MAC. SAR policies have a significant effect on data scheduling as they govern the distribution of packet size. We propose two new SAR policies for Bluetooth that give good performance in terms of throughput, delay and fairness. Finally, we include channel errors in Bluetooth and propose a modified scheduling algorithm that gives good performance.