Hitachi, Ltd.

Hitachi Communication Technologies, Ltd.

Akihiko Yoshida

Yosuke Takahashi

Shiro Mazawa

Daigo Takayanagi

Kiyoshi Kawamoto

Keiji Usuba

Shigeyasu Kubo

Rintaro Katayama

Toshiyuki Saito

Mikio Kuwahara

Keisuke Takeuchi

Nobuo Ito

Takashi Itamiya

Rumiko Nagano

A radio communication method in which, when hand-off of the down direction is performed while a radio mobile device subjects one application packet of the up direction to fragmentation to divide the one application packet into a plurality of radio packets and transmits the plurality of radio packets, sequence numbers of radio packets managed by a first radio base station to the plurality of fragmented radio packets of the one application packet even after the hand-off of the down direction is performed and to apply sequence numbers of radio packets managed by a second radio base station to fragmented radio packets of the application packet transmitted subsequently after completion of transmission of the plurality of fragmented radio packets of the one application packet; and making a radio base station accommodation apparatus identify a radio base station and restore data for each radio base station.

Radio communication method, radio mobile device and radio base station accomodation apparatus

A method for, in a radio communication system having at least a content server, plurality of base stations, and plurality of radio terminals, enabling two or more base stations among the plurality of base stations to broadcast or multicast data delivered from the content server to the radio terminals, the method includes: providing a Broadcast Multicast Service (BCMCS) Serving Node between the content server and two or more base stations; the BCMCS Serving Node includes a period number and sequence number into data delivered from the content server and transmits data including the period number and sequence number to the two or more base stations; in case that a synchronization is deviated or data is lost during data delivery from the base stations to the radio terminals, the base stations perform re-synchronization on a basis of the period number and sequence number included in data received from the BCMCS Serving Node.

Synchronous delivery method

An information transmitting method including; determining, on a basis of a packet error rate from a master station to slave stations, a number of times of multicast transmission in accordance with an expected value of a number of slave stations that transmit a retransmission request, an expected value of a number of retransmitted packets responding to the retransmission request, or a probability that the slave stations receive all packets forming information; notifying determined number of times of multicast transmission to the slave stations; and transmitting, to plural slave stations in multicast, same information formed of plural packets the determined times of multicast transmission.

Information transmitting method and information transmitting system

In order to narrow down base stations within the tracking-area-based paging area to ones within a smaller area where the mobile unit may exist in a mobile communication system performing the paging on the tracking-area basis, the mobile communication system has a location registration information database memorizing tracking area information, a last location registration information and a N-th (N is an integer of one or more) location registration information from the last for each mobile unit, calculates statistical data on a movement distance for each mobile unit based on the location registration information memorized in the location registration information database, and performs the paging via base stations included both within an area whose radius is equal to the calculated statistical data on the movement distance and within the tracking area.

Paging-area determination method and call-processing control apparatus in mobile communication system

A decryption key for decrypting data from an access node is distributed to an access terminal intending to receive the data. An authentication unit receives a message for terminal authentication including a terminal identifier from the terminal and authenticates the terminal. The authentication unit refers to a content registration table having stored in advance the content type of a content which the terminal can receive, in association with the terminal identifier, according to the received terminal identifier to obtain a corresponding content type. The authentication unit refers to a decryption data base having stored in advance a decryption key and its valid period in association with a content type, according to the obtained content type to obtain a corresponding decryption key and valid period. The authentication unit sends an authentication result and the decryption key and valid period to the terminal or to a packet control unit.

Decryption-key distribution method and authentication apparatus

In a wireless communication system, a base station control device has following two steps on the basis of latitude/longitude information obtained from a GPS, that is, a first step of recognizing, from the positional information obtained from the GPS, the fact that base stations in new and old systems are installed at the same location, and a second step of linking a neighbor list of the old system to a neighbor list of the new system with use of the result of the first step.

Wireless communication network, method of generating neighbor list in the wireless communication network, and control device therefor

Since the OFDM communication method does not select whether plural sectors use a same terminal as a transmission destination, or always use it as a transmission destination, giving a preference to system throughput deteriorates channel quality of a terminal in a sector boundary, while increasing channel quality in sector boundaries greatly deteriorates system throughput. In a base station, when a sector transmits to a terminal in the front of a beam, only the sector performs the transmission, and when transmission is made to a terminal in a sector boundary off the direction of the beam, a different sector transmits to the same terminal using a same hopping pattern. Thereby, tradeoff between the channel quality of the terminal in a sector boundary and deterioration in system throughput can be minimized.

OFDM cellular communication method, system and base station

An aggregation device performs a synchronous processing so that a synchronous delivery may be made from a plurality of base stations through a broadcasting channel. A BSN () gives, when it sends broadcasting data for the synchronous delivery to an AN () and an AN (), a period number and a sequence number are added to the broadcasting data so that the data to be sent from the AN () and the AN (can be synchronously delivered.

A wireless communication system including a wireless terminal, a plurality of base stations and a call processing control unit is disclosed. The wireless terminal, upon reception of the notification information from any of the base stations, judges whether the area included in the notification information is contained in the location registration area list stored in a storage unit, and in the case where the particular area is not so contained, sends a location registration request to the call processing control unit. On the other hand, the call processing control unit creates a new location registration area list based on the area included in the notification information and the neighboring areas, and sends the location registration area list to the wireless terminal thereby to execute the paging process.

Wireless communication system

A wireless communication system including a wireless terminal, a plurality of base stations and a call processing control unit is disclosed. The wireless terminal, upon reception of the notification information from any of the base stations, judges whether the area included in the notification information is contained in the location registration area list stored in a storage unit, and in the case where the particular area is not so contained, sends a location registration request to the call processing control unit. On the other hand, the call processing control unit creates a new location registration area list based on the area included in the notification information and the neighboring areas, and sends the location registration area list to the wireless terminal.

A call processing control apparatus automatically detects that a lot of handover and location registration simultaneously occur, and notifies a monitor control server. The monitor control server receiving the notification from the call processing control apparatus transmits a TAI change request to a base station so that a tracking area identity (TAI) of a movement destination cell where congestion occurs and a tracking area identity of a movement origin cell have the same value. The base station receiving the TAI change request message from the monitor control server changes its own TAI value. After that, all mobile devices perform only handover when they move between the cells where the TAI values are changed, and does not perform location registration.

Location registration area assigning method and wireless communication system

A transmission area is specified flexibly in accordance with the contents of a flow. An area identification number (SHOG) is specified for each interlaced stream of wireless base stations. The same flow is sent at the same timing (or substantially at the same timing) in the interlaced stream specified for the same SHOG. A wireless terminal determines a neighbor sector or a neighbor wireless base station sending the same flow, in accordance with information given from the wireless base stations, and receives and combines the flows.

Area management system

An AN (Access Network) controlled by a communication control apparatus and communicating with a AT Access Terminal), wherein the AN receives control information including information for allocating communication information from the communication control apparatus, and the AN transmits transmission cycle information for transmitting the communication information in a predetermined transmission cycle to the AT and allocates the communication information in the predetermined transmission cycle based on the control information received from the communication control apparatus to send the communication information to the AT.

Radio communication apparatus

A radio communication system including: ANs (Access Networks) for wirelessly communicating with an AT (Access Terminal); and a communication control apparatus for controlling the AN, wherein the communication control apparatus includes: a control unit for sending transmission cycle information and control information to the AN, and wherein the AN includes: a memory for storing information necessary for transmitting the communication information to the AT; a control unit for transmitting the transmission cycle information received from the communication control apparatus to the AT, calculating a transmission slot number necessary for sending the communication information in the transmission cycle, determining a transmission timing indicating a period in the predetermined transmission cycle allocated for the communication information, and transmitting the communication information in the determined transmission timing to the AT.

A radio communication system includes a grouping unit for grouping a plurality of base stations into a plurality of groups (Soft Handoff Groups) and a determining unit for selecting base stations belonging to one and the same group selected from the groups produced by the grouping unit and for determining the base stations as base stations to send communication packets to an access terminal.

Growing community of inventors

Yokohama, Japan

Akihiko Yoshida