Carrier-Sense ARQ: Squeezing Out Bluetooth Performance while Preserving Standard Compliancy

In this paper, we propose a simple and standard compliant retransmission mechanism, called carrier-sense automatic repeat request (CS-ARQ), which aims at improving system performance, both in terms of throughput and energy efficiency, by avoiding useless data packet retransmissions. More specifically, in case of missed acknowledgment (ACK), the source makes use of its carrier-sensing capabilities to decide whether retransmitting the data packet or soliciting the ACK retransmission from the destination. The scheme is modeled by means of a two-state Markov chain that permits to determine closed-form expressions for the throughput and energy efficiency figures. The analysis reveals that the CS-ARQ mechanism is actually capable of significantly enhancing the system performance, in particular in some critical scenarios, while preserving standard compliancy.