Efficient Audio Communication over Heterogeneous Packet Networks with Wireless Access

Communication networks are transforming towards all-IP networks with different fixed-line and wireless access technologies (e.g., DSL, UMTS, WLAN). One of the biggest challenges in such heterogeneous packet networks for the realization of real-time services (e.g., Voice over IP, music and video streaming) is dealing with transmission impairments which include variable packet transmission delays and packet losses. Current systems utilize different techniques to combat these impairments, such as a Jitter Buffer to compensate the variance in transmission delay and reduce jitter based losses, Forward Error Correction (FEC) to recover lost frames, and Packet Loss Concealment (PLC) to estimate unrecoverable frame losses. An issue which has not yet been sufficiently addressed is how to choose the best suitable methods and parameterize them optimally for a given scenario of application and transmission channel. This dissertation develops a new methodology to analyze and determine the most suitable FEC method for a given transmission scenario. This approach aims at the best possible transmission quality by considering both signal quality and end-to-end delay.