Abstract: In some special fields such as military,patrol,rescue and relief,fieldwork and other emergency situations without infrastructure support,a stable and effective communication system is needed.An emergency communication system supporting real-time voice and video is designed and completed based on the Ad Hoc network,embedded system,and QT multimedia development.The optimized link state routing protocol is selected with the use of RTP,Speex and Ffmpeg to control the noise,echo and jitter of voice transmission effectively and to ensure low delay video and audio transmission with variable bit rate support.Tests show that the system is capable of fast building with support for multi-hop,broadcast and multicast and with fluent and stable message,voice and video communication.

Key words: Ad Hoc;optimized link state routing protocol;ARM;QT;real-time audio and video;433M