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).
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. P...