Audio-visual conference through the ionosphere at 4 kbps

Unlike in data communications, multimedia communications through heterogeneous networks is still far from being achieved due to a lack of solutions at all protocol layers. We are evaluating the performance of a high frequency (HF) wireless network for transporting multimedia services. Beyond allowing civil/amateur communications, HF bands are also used for long distance wireless military communications. Therefore, our research work is based on NATO link and physical layer standards, STANAG 5066 and STANAG 4539 respectively. A typical transmission bandwidth is of about 3 kHz with a throughput bit rate up to 12800 bps, resulting in a very low channel capacity and therefore imposing serious challenges for reliable real time multimedia communications. The paper describes a complete video conference system designed to allow end-to-end communication and discusses the quality of service in terms of packet loss and delay