Cross-layer optimized routing for Bluetooth personal area network

We present some observations and analysis on Bluetooth PAN's performance degradation in multi hop network based on our experiments. We highlight a situation in which control packets can be received properly but not data packets, as well as its effects on scatternet performance. Based on our analysis, we propose a cross-layer optimized routing protocol for Bluetooth (CORB), which outperforms AODV based routing protocols. CORB is a QoS-extended AODV routing protocol that is optimized for Bluetooth MAC. It has two unique characteristics. First, it uses a new load metric (LM) in QoS routing protocol instead of the number of hops as in conventional best effort routing. LM reflects nodes' link bandwidth with respect to Bluetooth nodes' role in the scatternet. This helps the CORB to bypass heavily the loaded nodes, and find routes with larger bandwidth. Second, LM and some MAC layer parameters are dynamically adjusted in response to the changes in radio conditions. These two characteristics of CORB contribute to its improved stability, and rapid response to changing radio conditions.