This paper discusses an efficient design and implementation of control and multiplexing protocols H.245 and H.223, which is an important part of 3G324M protocol stack, for mobile wireless video conferencing. Our implementations aim to support the multipoint video conferencing with the capability of transmitting/receiving multiple video/audio streams simultaneously. Conference managements such as admission control, video/audio channel management are also discussed. As a result, the implementation improves efficiency and makes the conference more convenient to set up and to operate. Our prototype system is stable and its performance is satisfactory.