Takahiko Yamada

Mobile multimedia metropolitan area network; an office LAN extension to the 4G mobile network

This work proposes an MM-MAN (mobile multimedia metropolitan area network) featuring extended Office LAN services as a component of the 4G mobile networks. The extended LAN services offer VPN circuits between mobile terminals and their home office LAN, and allow mobile terminals to behave as if they were in the home office LAN. The VPN circuit here means IP address concealment using private IP address offered by the MM-MAN. Payload should be concealed by the users themselves; since the terminal is considered to be in the office LAN itself, and thus, users do not want payload encryption and decryption by the network operator. To support fast mobility, PON (passive optical network) is used as terrestrial network of the MM-MAN. Downlink packets are broadcast through PON to all micro-cells in the same LMC (logical macro-cell) to allow packet transfer over the wireless interface to fast-moving terminals at any cell, and uplink packets can be sent out from any micro-cell in the same LMC. The LMC consists of several adjacent micro-cells. To quicken packet transfer to moving terminals in the micro-cellular environment, polling is conducted in parallel in every micro-cell of each LMC, and the micro-cell, which receives response multicasts the response to other micro-cells to synchronize for the next polling.

Mobile multimedia metropolitan area network

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.This paper introduces our project named MM-MAN (Mobile Multimedia Metropolitan Area Network) aiming to provide high-bit rate packet transfer to fast-moving terminals in a micro-cellular network. One of the advanced services assumed in MM-MAN is a LAN extension to the cellular network. This paper first presents advantages of MM-MAN compared with a mobile network constructed with a double tier-cell configuration. To support a fast move of terminal, we propose LMC (Logical Macro Cell) concept and parallel polling mechanism. Adjacent cells are grouped into a multicast-based LMC at which the same data packets destined to a mobile user buffered to eliminate a re-transmission delay. Moreover, this LMC is not static but switched over together with a change of mobile user to a new cell. In the wireless section, instead of contending for channel of a new cell that causes unbounded delay, polls are sent from neighboring cells to reserve channels for mobile users at these cells. We call it a parallel polling mechanism. Our simulation results reveal that the parallel polling and dynamic LMC work well to offer smooth high- data rate to fast mobile users with a moving speed up to 250 km/h in the microcellular environment without any obstacle.

Logical macrocells of mobile multimedia metropolitan area network

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 LMCs 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.

All IP future mobile wireless access network; passive optical network, dynamic logical macro-cell, and IP multicast

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.

Another double tier to avoid local congestion in a unified microcellular network

This paper proposes a unified micro-cellular network for future multimedia communications, and proves that its capacity can be several thousand times bigger than todays 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

High-bit-rate packet transfer to fast mobile terminals in an IP based micro-cellular network with parallel polling scenario

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.

Analysis of parallel polling to maintain high-speed packet transfer for fast-moving terminals in microcellular network

The paper presents packet transfer control procedures in an MM-MAN (mobile multimedia metropolitan area network) which is considered to be a component network of beyond-3G, and is deployed along main roads in metropolitan business areas. The MM-MAN supports IP-based, high bit rate packet transfer to fast- moving terminals in microcellular networks. To satisfy a smooth handover with fast movement, the concept of a logical macrocell (LMC) is introduced which consists of a number of adjacent microcells. A set of polling signals is emitted in parallel to every microcell in the LMC, and packets are transferred in one of the cells where the target mobile terminal exists. Polling ACK is multicast to every microcell in the LMC to synchronize the parallel polling. For exceptional cases, like polling ACK error, time-out re-polling should be set independently in each microcell in the LMC. Packet transfer throughput of each terminal depends on the packet size and ACK multicast delay. In the case of 200 /spl mu/sec multicast delay, the throughput over a 100 Mbps packet-multiplexing medium is 7.171, 17.927 and 57.368 Mbps for 200, 500, and 1600 byte packets, respectively. The throughput in each base station depends on the packet size. It is 15.54, 31.5, and 59.54 Mbps for 200, 500 and 1600 byte packets, respectively. The throughput is shared by a number of mobile terminals in each microcell.

Unified micro-cellular network with Pico-cells to avoid local congestion

Micro-cellular networks have advantage of the radio band reusability over macro-cellular networks though they have drawbacks; frequent handovers disturbing smooth packet transfer and local congestion closed in micro-cells. MM-MAN (mobile multimedia metropolitan area network) the authors have been studying is a unified micro-cellular network in which micro-cells for fast terminals are deployed along major roads in metropolitan area. This paper presents how the MM-MAN solves two major drawbacks of micro-cellular network. To avoid frequent handover, polling is emitted to each micro-cell in an LMC (logical macro-cell) consisting of several adjacent cells, and packet transfer is conducted in one of micro-cells to which polling response comes. The LMC switched-over is triggered when the terminal move to the next cell is detected by the network side. The local congestion which can typically happen around cross-sections can be released with a small double tier, micro-cells with pico-cell. The capacity of the unified micro-cellular network can be much larger than that of the conventional double tier network

PON mobile access network without Mobile IP FA switchover

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.

Mobility management in MM-MAN (mobile multimedia metropolitan area network)

The authors have been studying an IP-based microcellular network named MM-MAN (mobile multimedia metropolitan area network) which is assumed to become a component network of the 4G mobile systems, and will be deployed along major roads in metropolitan areas. One of the most advanced services of MM-MAN is LAN extension to microcellular network providing moving office to business users during fast driving. In order to satisfy such a special service in the cellular environment, mobility management in MM-MAN should be considered to allow upkeep of the identical IP address during quick cell-to-cell move. To achieve this, the LMC (logical macrocell) which consists of several adjacent cells and is virtually regarded as a single cell is designed. A downstream packet to a targeted MT (mobile terminal) is cast in every base station in an LMC through a multicast tunnel which corresponds to the LMC. The MT can be identified with an identical IP address if it stays in the LMC through the multicast tunnel. To follow the terminal moves, a polling set is emitted to every microcell in the LMC, which is switched over to the next LMC which central microcell the polling response comes to when the target MT moves to a different microcell. A PON (passive optical network) which provides broadcasting capability is used as the terrestrial network.