DFCM： A Distributed Floor Control Mechanism in PoC  

作　　者：LIAO Jianxin LIU Haipeng LI Tonghong WANG Jingyu ZHU Xiaomin 

机构地区：[1]State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, Beijing 100876, China [2]EBUPT Information Technology Co., Ltd., Beijing 100191, China [3]Department of Computer Science, Technical University of Madrid, Spain, 28660

出　　处：《Chinese Journal of Electronics》2011年第4期739-746,共8页电子学报（英文版）

基　　金：This work is supported by the National Science Foundation for Distinguished Young Scholars （No.60525110）, the National Basic Research Program of China （973 Program） （No.2007CB307100, No.2007CB307103）, the National Natural Science Foundation of China （No.61072057, No.60902051）, the Fundamental Research Funds for the Central Universities （No.BUPT2009RC0505） and the National Key Science and Technology Specific Project of China （No.2011ZX03002-001-01, No.2011ZX03002-002-01）.

摘　　要：With the fast progress of Collaborative multimedia application （CMA） running on overlay net- work, Push to talk over cellular （PoC） attracts signifi- cant interest in the field of mobile cellular communications. PoC is an on-demand, resource efficient, half-duplex mul- timedia service. Due to the half-duplex nature, only one user is allowed to speak at a time, and the others listen. If listeners want to speak, they have to contend for the right to speak and wait for the permission if request waiting is supported. Open mobile alliance （OMA） proposed a centralized controlling based floor control mechanism for speak right coordination in PoC, which is called Talk burst control protocol （TBCP）. But it has many limitations in scalability, reliability and robustness as all centralized ap- proaches have. In addition, none of available distributed approaches well meets mobile users＇ requirements in PoC, especially for the request waiting function. In this paper we put forward a novel distributed floor control mechanism with request waiting for PoC, which is called Distributed floor control mechanism （DFCM）. From the performance evaluation of DFCM and TBCP, we find that DFCM out- performs TBCP especially when performance of the central node, Controlling server （CS）, drops down due to heavy load. Finally, this paper is summarized and future work is forecasted.

关 键 词：Collaborative multimedia application （CMA） Push to talk over cellular （PoC） IP multimedia subsystem （IMS） Floor control Request waiting Distributed controlling. 

分 类 号：TN929.53[电子电信—通信与信息系统] TD942.89[电子电信—信息与通信工程]