The Architecture of Mobile Multimedia Metropolitan Area Network towards the Future of the 4G Mobile System

One of objectives of the future 4G mobile network is to provide broadband connection to mobile users regardless of their speed. Microcellular-based mobile networks must be an essential one in the 4G mobile generation from the view of rich radio resource for multimedia communications. This paper presents the architecture of MM-MAN (mobile multimedia metropolitan area network) network of which target is to become one of mobile network candidates for the 4G systems. In this mobile network, high-bit rate packet transfer is stably guaranteed even to FMTs (fast moving terminals) by the operation of an LMC (logical macro cell) and parallel polling. The mechanism easily allows 5Mbps packet transfer to terminals with speed of 100km/h. To enable synchronization of parallel polling, ACK of polling is multicast to BSs in the same LMC through the backbone network. The time the polling ACK multicast transmitted in the terrestrial network is a significant factor that will decide the throughput of mobile terminals. Owing to PON (passive optical network), which constructs the terrestrial network of MM-MAN, parallel polling and LMC can be done easily. A key advantage of PON over MM-MAN is its high bandwidth broadcast functionality that can turn into multicast without vulnerability to its bandwidth is used to enable parallel polling and the LMC operation. In the case of EPON with static slot allocation scheme, ACK multicast time depends on the grant time for each ONU and the number of ONUs connected to an OLT on one fiber. From our evaluation, if the ACK multicast delivered in PON from 0.5 to 4ms, the throughput that a mobile terminal can get is from 25Mbps to 5Mbps for the case of 1500bytes of packet size. The PON system can work adaptively to fasten ACK multicast if the number of ONUs on which a base station stands connected to an optical line terminal (OLT) is 16.