Real-time audio transceiver utilizing 802.11b wireless technology

Abstract

This paper describes the design and testing of a device that employs pre-built IEEE 802.11b wireless cards in a real-time audio application. IEEE 802.11b WiFi cards have been used for high data rate applications where latency is not of primary concern. The main goal was to investigate if IEEE 802.11b would be capable of handling the type of load created by audio transmission. The application for this specific device is a wireless guitar transmitter/receiver for real time transmission between a guitar and an amplifier. For testing and analysis purposes, two embedded boards interfaced to IEEE 802.11b Compact Flash cards were connected in an ad hoc network. A 16 bit, 44.1 kHz mono signal was selected in order to ensure the quality of the audio output. Buffering was implemented at both the transmitter and receiver for reliability with careful selection of the buffer length to ensure no perceivable latency. Both the wireless card configuration and packet headers were primary issues in operating IEEE 802.11b in a real-time scenario. Timing results and the overall system performance will be presented in this work.