This paper presents possibility of dense small cell network for local areas from a view of network control considering two types of applications; one is 100m cells for a major road supporting vehicles' mobility and another one is 10m cells for campuses supporting walking mobility. They adopt 3GLTE protocol after slight modification. Handover is directly triggered from a UE (User Equipment) to a target BS (base station) to shorten the handover period though it is relayed on a serving BS in conventional systems while drawing large latency due to backhaul communications. The direct request uses SR (Schedule Request) signal on PUCCH (Physical Uplink Control Channel) of 3G-LTE protocol. This can be allowed by short propagating delay in a small cell and synchronous operation of all BSs under clock of PON (Passive Optical Network) used for the backhaul network. Handover resources like SR codes, downward frames, and terminal ID are reserved among the target UE and a group of BSs next to one serving the target UE before handover. Cells surrounding the target UE follow the move of the UE always confining the target UE in the cells with the reserved handover resources.

This paper evaluates how the parallel polling and LMC (logical macro cell) designed operating in the micro-cellular MM-MAN (mobile multimedia metropolitan area network) can provide high-bit-rate packet transfer to fast-moving terminals (FMTs). An LMC groups several adjacent micro-cells in a multicast group to a virtual single macro cell. LMC is always switched over together with a motion of FMT when it comes to a new BS. Data packet destined to the mobile users is multicast within an LMC. A set of polling signals is emitted from every micro-cell BS of an LMC to permit packet transferred to and from an FMT within the LMC coverage. Handover between micro-cells is done if FMT receives and answers to a polling sent from a new BS, other wise it continues handling connection with the current BS. Multicast of the polling response to every micro-cell BS within an LMC is required to synchronize sending polling. Therefore, moving of FMT between micro-cells in an LMC likes in one larger virtual cell that makes the handover of FMT become simple and smooth. Our simulation results reveal that the parallel polling and dynamic LMC work well to offer a fast mobile user a smooth high-data rate connection in the microcellular environment with regard to low handover latency, high throughput and no end-to-end delay. The evaluation is done using the OMNeT++ simulator.

This paper proposes a unified micro-cellular network for future multimedia communications, and proves that its capacity can be several thousand times bigger than today's widely accepted double-tier architectures in which low speed terminals are accommodated in micro-cells whereas fast terminals are served in overlapped macro-cells. In the unified micro-cellular network, micro-cells are deployed along major roads of a metropolitan area to offer high bit-rate packet transfer to fast moving terminals. A set of polling is emitted in parallel in several adjacent micro-cells, configured to a logical macro-cell (LMC), and the LMC formation is changed following the movement of the fast terminal (more than 100km/h) to avoid frequent handovers. Moreover, to prevent local congestions which can easily happen in cells of e.g. a road junction, a new double-tier structure is proposed so that pico-cells are included in micro-cells with frequent local congestion. Pico-cell does not affect neighbor-cells, since it is enclosed in the target micro-cell. The capacity increase of the target micro-cell depends on the size and the channel number of each deployed pico-cell

This work presents an all IP based micro-cellular network configuration used in the metropolitan area. It aims to provide high-bit-rate packet transfer to fast-moving terminals. With the high transfer rate and guaranteed security, it can be considered as the extension of corporate LAN for business uses. For avoiding contention based access delay and packet re-transfer delay during handover, a new parallel polling scenario is proposed. Operating within the range of logical macro cell (LMC), detailed packet transfer procedures of polling are explained. Also automatic switching-over of LMC that locate the mobile terminal (MT) at the center cell of LMC all along can reduce the burden of strict time frame faced by the MT during high frequency handover between micro-cells.

Mobile multimedia metropolitan area network (MM-MAN) is proposed to offer high-bit-rate IP-based communications for high-mobility terminals inside metropolitan areas. To offer high-level security for users, a VPN Agent is located in the MM-MAN access network, and a VPN server is located at the MM-MAN user's home network. This paper proposes several alternative security scenarios to fulfill the security requirements of the MM-MAN in such a hybrid environment. Virtual private network (VPN) is set up to encrypt the privacy, and network address translation (NAT) is conducted to translate between user's original IP address within the home network and private IP address within the MM-MAN. we also give a quantitative analysis of the overhead ratio per packet in each scenario and compare the efficiency of all scenarios. We conclude that private IP address with NAT at the VPN Agent scenario is a feasible scheme.

This paper presents a logical macrocell configuration in a microcellular network in which the capacity is larger than a conventional macrocellular network. And the network provides high-bit-rate communications to fast-terminals with smooth soft-handover. The application used in the network is mobile multimedia metropolitan area network (MM-MAN) which offers high-bit-rate IP communications for high-mobility terminals in metropolitan areas. We present a combination of wireless and wired network technologies to implement MM-MAN. Secure virtual private network (VPN) tunnel and seamless continuous services in microcellular network are basic requirements of MM-MAN. Passive optical network (PON) is adopted as the access network to support a great deal of optical network units (ONU) which controls each microcell. To reduce packet loss of high-mobility terminal caused by frequent handovers in the microcells, we configure logical macrocell (LMC). The LMC also makes use of IP packet multicast to support micromobility of the VPN tunnels. Through replacing the traditional macrocells with both microcells and LMC's which aims at fast-moving terminals, we increase the available spectral capacity which can be used to provide up to 80 times increase in bandwidth compared to macrocells, even if 30 % of the users are fast movers.

This paper proposes a mobile multimedia metropolitan area network (MM-MAN) which provides IP-based VPN connections between mobile terminals on business activities around metropolitan area, and LAN in their own home office. To make VPN circuit handed over on cell-by-cell traverse, a VPN agent exists in MM-MAN access networks, and VPN server in each office network. Tunneling between VPN server in LAN of home office, and VPN agent in the MM-MAN is used to support macro-mobility. To support high level business activities, all information which can reveal business activities should be hidden from the third party. To be neutral, private address is used as a source and destination in each VPN connection even to designate IP terminals in its own office, and is used even during the VPN setup to terminals in the Internet. Micro-mobility support for high-speed and high-bit rate terminals is a role of PON (passive optical network) as an access network. Multicast communication is used in a PON access network to construct logical macro-cell in order to allow smooth handover for high-speed terminal.

We propose a dynamic logical macro-cell to support fast movers in a wireless mobile multimedia access network. The network assumes a micro-cell structure, and uses passive optical network (PON) technology for fiber distribution to the radio cells. The broadcast functionality of PON together with IP multicast is used to construct the logical macro-cells. Evaluation of static and dynamic logical macro-cells show that the dynamic macro-cell uses resources efficiently, and relaxes the response time for handovers, at the expense of a slight increase in signaling transactions and IP multicast group updates.

We introduce a PON (passive optical network) mobile access network as a candidate to offer continuous multimedia IP communications to fast moving terminals in a microcellular environment. As an alternative to IP micro-mobility protocols, we propose a PON access network with the foreign agent (FA) distributed over all access points connected to the same fiber. All ONU (optical network units) associated with the same FA are given the same IP address, and mobility inside the area of a single fiber is transparent to the IP layer. Our architecture thus supports soft handover for IP transmissions on the downlink inside each fiber, at the same time as the home agent (HA) update frequency is reduced. Simulations showed that at 70 km/h in a 100 m microcellular network with PON clusters of 30 cells, HA update occurs every 25 seconds, compared to every five seconds if a unique FA is located at each access point.

Aimed at the application to processors used in communications networks, three kinds of custom CMOS VLSI chips, each integrating approximately 10 kilogates, were developed. During the development of these chips, we overcame various restrictions on the VLSI design, such as input/output pin limitations, bug correction difficulty, and input/output signal delay. A combination of the software and hardware simulators efficiently eliminated logic errors. Microprogram control memory is placed externally to VLSI chips to facilitate tentative correction of possible remaining errors. Two types of processors sharing uniform architecture were also developed for an overall optimum cost-effectiveness using these VLSI chips. One uses all three kinds of VLSI chips and is suitable for switching and communications processing applications. The other includes one VLSI chip and consists of a single printed circuit board. It is suitable for a portable console processor or a processor imbedded in various equipment. These VLSI processors are being introduced in large numbers in communications networks in Japan.