Audio Streaming with Silence Detection Using 802.15.4 Radios

Short-range radios with low data rate are gaining popularity due to their abundant commercial availability. It is imperative that high-speed multimedia would be an attractive application field with these radios. Audio over 802.15.4 compliant radios is a challenging task to achieve. This paper describes a real-time implementation of audio communication using 802.15.4 radios. Silence detection and soft ADPCM are the main features of our work. Our results show that silence detection improves bandwidth optimization and audio communication performance over low bit-rate radios. 1. Introduction Wireless technologies due to their attractive features like wireless connectivity, easy and quick installation, and low energy operations are making inroads in various application domains. Major wireless technologies are WiFi (Wireless Local Area Network over IEEE 802.11a/b/g), Bluetooth, WPAN (Wireless Personal Area Network over IEEE 802.15.1), and LRWPAN (Low Rate Wireless Personal Area Network over IEEE 802.15.4). WiFi being designed for long-range and high-speed data rates has already had its impact on local area networking and wireless data networks. Bluetooth was primarily designed for short-range wireless connectivity and has found its effective application areas in computer and consumer peripheral connectivity. The Bluetooth is the most complicated protocol with 188 primitives and events in total. On the other hand, LRWPAN is the simplest one with only 48 primitives defined in 802.15.4 [1]. LRWPAN is an emerging technology for low data rate small networks like WSN, home automation, security surveillance systems, precision agriculture, medical health care networks, and sensitive military applications. Due to its all encompassing coverage of application domains, it has become imperative to explore multimedia streaming over LRWPAN. Audio transportation over LRWPAN is an important area opening many possibilities for the application areas like wild fire detection, habitat monitoring, and environmental monitoring. In particular they will be useful in distributed surveillance, emergency, and rescue where audio and video streaming over low cost LRWPAN networks is highly desirable [2]. The challenges of multimedia over WSN are discussed in [3]; authors note that high bandwidth demand and strict time-constraint of multimedia communication bring significant challenges for sensor networks in matching the energy and processing capacities. This work presents a case study of real field implementation of audio streaming over LRWPAN short range radio network specifically