Jong-Hun Park

Model and performance evaluation of a piconet for point-to-multipoint communications in Bluetooth

We consider model and performance evaluation of the Bluetooth system supporting point-to-multipoint communications in a piconet. In order to support more than seven slave devices in a piconet, a park mode is considered and modeled. We evaluate the performance, i.e., throughput and delay, using simulations when multi-connections (both A CL and SCO connections) are present in a piconet. We show that the data rate may be less than 10 kbps when SCO connection(s) and more than six ACL connections are jointly supported in a piconet. In addition, if up to four ACL connections are supported, the average delay is shown to be maintained less than 10 msec. Our results serve as a guideline to the design of Bluetooth systems with throughput and delay requirements.

Reliable delivery of broadcast packet in Bluetooth

In the Bluetooth wireless system, each broadcast packet is retransmitted for a fixed number of times. However, there is a trade-off between the number of retransmission and the effective throughput. Also, reliable packet delivery is not guaranteed. Therefore, we propose a reliable broadcast packet delivery policy, which is called NACK-based retransmission policy in which the number of retransmission is dynamically adjusted in order that all the slaves can receive the packet correctly. Our simulation results show that the NACK-based retransmission policy guarantees reliable packet delivery and maximizes the effective throughput by preventing a broadcast packet from being retransmitted unnecessarily.