Phan Thanh Hoa

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

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.

From macrocell to microcell system to offer road communication to vehicle

In future, mobile multimedia services will become popular as widely as the use of the cellular phone today. It makes the bandwidth required for each multimedia service increase rapidly, and such kind of communication will be dominant since the development of machine-machine communications for human interactivity in the multimedia age. For this demand, the micro-cell will become a major role in substitution of the macro-cell. This paper proposes a new paradigm of mobile network system where a virtual single cell over connected micro-cells used to release the traffic load of macro-cells, and an IP-based paging network offering mobile users the seamless connection between networks through vertical handover functionality. New connected micro-cells network is to support vehicular users the broadband mobile services like mobile tele-medicine, teleconferences, online-game, etc and can be used for ITS (Intelligent Transport System) and shares the traffic load with the Macro-cell network. In order to become feasible, the first important issue need to be solved is mobility management because it is supposed to server for fast moving terminals. This paper also presents the virtual single cell mechanism; an LMC (Logical Macro Cell) and multi-polling to LMC to make resource reservation to adapt to quick change of access points of fast MT. Performance of achievements is reported to evaluate our proposal.

Performance of Dynamic Logical Macro Cell and Parallel Polling to Support Smooth Handover to Fast Movers in Microcellular Networks

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.

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 cellpsilas 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 5 ms, and the throughput for MT in case of the continuous multimedia like moving picture is 2 Mbps over the 54 Mbps wireless interface.

Mobile Multimedia Metropolitan Area Network

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.

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.