Distributed mobility management for fast terminals in an IP-based micro-cellular network along roads

This paper presents a scalable control system for a unified micro-cellular network named MM-MAN (Mobile Multimedia Metropolitan Area Network) in which fast terminals are provided high-bit rate IP packet transfer. In our previous papers, proposed schemes to guarantee smooth connections to fast movers in spite of frequent movement are LMC (Logical Macro Cell) and parallel polling. LMC-a multicast group of adjacent micro-cells and pollings are emitted from all BSs of the same LMC create a symmetric environment as a virtual single cell so the cell-to-cell movement of a mobile terminal within an LMC can be passed over. Detail of the distributed control for mobility management is described in this article. An extended LMC is introduced to conduct pre-downloading of packets and to allow distributed processing for the LMC switchover. However, the radio active channel is manipulated only at BSs in the LMC range but not in the extended LMC to save radio resources due to the overhead of parallel polling. If the polling response comes to the BS which differs from the central cell's BS of the LMC, this BS will be placed to become the central cell of the new LMC, and polling acknowledgement is multicast to the new extended LMC. The neighboring BS on the movement direction of the target mobile terminal (MT) can realize movement of the MT, and starts actions to join the new LMC by itself without help from the centralized control. These procedures can hide the delay in the cell-to-cell movement of the terminal even when it goes out from the LMC, and guarantee scalable and high-performance control over micro-cellular network. The simulation results tells the handover latency is less than 5ms, and the throughput for MT in case of the continuous multimedia like moving picture is 2Mbps over the 54Mbps wireless interface.