Packetization Scheme for Streaming High-Quality Audio over Wireless Links

Abstract

The rapidly advancing wireless communications technologies enable true multimedia streaming services in mobile devices. In contrast to fixed IP networks, the majority of packet losses in a radio access network are not caused by congestion, but bit errors in the physical transport channel. To allow more efficient utilization of the radio spectrum, proposals have been raised to allow delivery of packets containing bit errors up to the application layer. This approach is very beneficial for real-time applications if the decoder is able to handle partially damaged data. However, the most efficient multimedia codecs are typically vulnerable to bit errors. This paper describes an optimized packetization scheme for streaming high-quality audio compressed with Advanced Audio Coding (AAC) coder over a packet-switched network that is prone to bit errors. The scheme is based on rearranging Huffman coded data in multiple transport packets, aiming for restricted error propagation and smoother distribution of bit errors. It has been evaluated by streaming robust stream in a test network simulating a wireless transport channel. According to the test results, the proposed approach improves network resource utilization measurably without substantial degradation in audio quality.