Journal of Networking Technology Joohan Lee, Juho Lee, Sungkwon Park 6 2 2015 Mobile WiMAX access network is being developed to support various multimedia services such as mobile Internet Protocol Television (IPTV), mobile Video-on-Demand (VoD), and mobile Internet services. In multimedia systems, one of the major challenges is how to reduce a channel change response time. In order to solve this problem, many methods have been proposed. In this paper, we propose Cross-Layer Optimization and System Architecture of Multicast Broadcast Service (MBS) over mobile WiMAX. Proposed method reduces the channel change response time efficiently as viewers watch mobile IPTV channels without IGMP join process when those are shared. Simulation results show that the channel change response time is significantly decreased compared to the existing MBS architecture.