Abstract: In order to provide a redundancy configuration to an access gateway apparatus in which a control plane and a user plane are separated, the access gateway apparatus includes: a control computer for receiving control signals from the networks to establish the communication path, thereby determining packet transfer information for the data; and a transfer computer for receiving the packet transfer information from the control computer to transfer the data through the communication path. The transfer computer includes: a plurality of first transfer computers for executing the transfer of the data; and a second transfer computer for taking over, when a fault occurs in any one of the plurality of first transfer computers. The control computer includes: a first control computer for processing the control signals received from the networks; and a second control computer for taking over, when a fault occurs in the first control computer.

Abstract: A radio system has silence periods in which wave transmission from a terminal is stopped and in which a base station measures external noise power. The base station includes a receiver for receiving a signal from the terminal, and a controller that has preset frequency information representing a frequency of diagnosing the receiver to a measurement frequency of external noise power, and diagnoses normality of the receiver by using one silence period out of plural silence periods on the basis of the frequency information while measuring the external noise power by using the other silence periods. When the receiver is diagnosed, the external noise cannot be measured during this silence period, and thus during this silence period the external noise measured during the just preceding silence period is held and applied as external noise under the diagnosis of the receiver.

Abstract: The total system, which is operated by SIP (Session Initiation Protocol) call sequence and SIP call replacement sequence, comprises control part which includes sequence part for immediately performing the SIP call replacement sequence upon detecting communication of call forwarding or proxy response, SIP exchange equipment which includes storage part for storing sequence program of the call forwarding and proxy response, SIP telephones 3a to 3n, and a network such as Internet or wide LAN to which the SIP exchange equipment and SIP telephones 3a to 3n are connected, so that it is able to provide the SIP exchange system for agreeing a final party in communication and party number display, even an party responds the incoming call is changed by the call forwarding or proxy response.

Abstract: In a case where a switching source wireless communication system is a wireless communication system in which a transmission timing of a packet or data rate can be controlled in a wireless base station, the switching source wireless communication system, which notifies information on a timing when a wireless terminal communicates the switching destination wireless communication system with respect to the switching source wireless communication system in advance, starts time-division communication between switching destination and switching source wireless communication systems, and receives the timing information, controls a transmission timing or a data rate in accordance with the timing information.

Abstract: 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.

Abstract: A unit timing signal synchronized with a high-order transmission frame is used for measuring a difference between the number of data pieces of a client signal mapped to the high-frequency frame and the number of data pieces of the output client signal by integrating the difference therebetween for each unit timing signal. Then stuffing and de-stuffing operations are performed so that a integration result is zero.

Abstract: The invention provides a call connection control method which can use a conventional telephone as-is and performing linking with a low possibility of mistaking telephones, and a call connection control unit for implementing the method. Upon receiving an outgoing call request from an outgoing-call side personal computer (PC), a call connection control unit retrieves an outgoing-call side IP-telephone linked to the PC, and transmits an incoming call request to the IP-telephone. Upon receiving the incoming call request, the IP-telephone rings. When the caller places the IP-telephone that rings in a starting (off-hook) state, the call connection control unit sends a ring back tone to the IP-telephone and transmits an incoming call request to an incoming-call side IP-telephone. Upon receiving the incoming call request, the IP-telephone rings. When the recipient places the IP-telephone that rings in a starting state, the call connection control unit enables a call between the two IP-telephones.

Abstract: A radio communication terminal, being used in a radio communication systems in which the transmission rate varies depending on radio wave conditions and communication statuses of other users, comprises a reception module which receives packets transmitted by a base station in an idle state of the radio communication terminal, a signal processing module which estimates a transmission rate available in communication based on the packets received by the reception module, and a display module which displays information indicating the transmission rate estimated by the signal processing module.

Abstract: To provide a wireless base station comprising an array antenna which transmits packets to terminals, a packet scheduler which determines transmission sequence of the packets, a modulator which generates modulated signals based on the packets, and a beam former for transmission signal which multiplies the packets with array weights for transmission signal and outputs the transmission signal to the array antenna the beam former for transmission signal comprises a memory which stores the array weights for transmission signal associated with the terminals' IDs. The beam former for transmission signal receives the IDs of selected terminals from the packet scheduler, refers to the memory, and selects the array weights for transmission signal by the IDs of the terminals.

Abstract: An object of the present invention is to solve a problem that when multicast is utilized in a network configured with virtual routers, traffic in the relay network is increased. According to the present invention, the number of multicast packets via the relay network is reduced by performing a multicast packet transfer across the virtual routers within the same router. Specifically, it is allowed to register in a multicast routing table held by each virtual router, a line interface identifier of another virtual router as outgoing line interface information, whereby multicast packet transfer from a virtual router to another virtual router is made possible. In order to specify a virtual router to share the multicast packet, each virtual router holds information to specify a virtual router having a line interface to receive the multicast traffic indicated by the multicast group address.

Abstract: In a mobile communication system having an ATM-processed transfer path, a non-instantaneous interrupt handover can be realized. In a mobile communication network including an ATM-processed transfer path, when a mobile station is moved between cells during communication, frames are received to be identified by a mobile switching center. The frames contain the same data received from both base stations covering the cell range at asynchronous timing different from each other. A selection is made of header information with the lowest error rate from the header information of these frames. The frames are connected at instructed timing. Also, the frames to be transmitted to a plurality of base stations are duplicated, and then transmission timing is specified from these header information. These duplicated frames are transmitted at the specified transmission timing, so that the non-instantaneous interrupt handover is carried out.

Abstract: In a case where a cellular phone exists outside a WOS system service area, the cellular phone receives a not-connectable signal and an audio message from a mobile switching controller. The cellular phone conducts disconnection processing with the not-connectable signal as a turning point. Moreover, the cellular phone stores an extension number and converts a dedicated special number into an external number for retransmission, thus establishing connection to a PBX. After the reception of a connection-accepted signal and an automatic exchange answer message from the PBX, the cellular phone automatically transmits the stored extension number.

Abstract: Terminals #1 to #3 which have already been connected and a terminal #4 which wants to make a new connection send packets to a base station in that order. The base station queues the packets from the terminals #1 to #3 at a non-priority queue and the packet from the terminal #4 at a priority queue. For example, a predetermined amount of packets from a new connection is queued at the priority queue. Packets in the priority queue are dequeued with priority. Therefore, the packet sent from the terminal #4 is first sent to a base-station controller, and then the packets sent from the terminals #1 to #3 are sent to the base-station controller. As a result, the base-station controller first receives the packet sent from the terminal #4, and the period of time required for the terminal #4 to establish a connection is reduced.

Abstract: An optical add-drop function part of an optical add-drop multiplexer has an output end of transmitted light signal in which an optical termination mechanism formed by an optical detector for detecting open of an optical fiber, an optical switch, and an optical terminator are mounted. Further, a reflection level calculation circuit, a reflection warning determination circuit, and an optical switch selection circuit are mounted to perform laser safety in the optical add-drop function part as well. The laser safety part in the optical add-drop function part is operated earlier than the laser safety part in an optical amplification function part.

Abstract: A Passive Optical Network system implementing a parent station capable of receiving high-speed burst signals transmitted from a plurality of subsidiary stations to a parent station, with excellent bandwidth utilization efficiency in the link from the stations to the parent. The system is provided with a configuration in which, when launched or an addition of a new subsidiary station, the parent stores threshold values appropriate for the received signals on the basis of the strength of the received signal for each subsidiary station, from among a plurality of preset threshold value candidates, and in response to the parent station's sending of a transmission grant with respect to each subsidiary station each time the subsidiary station transmitting optical signals changes, the stored threshold value corresponding to the subsidiary station is set in the receiver circuit.

Abstract: In a PON system, an OLT periodically transmits a channel resource information block specifying a carrier wavelength and a spreading code on a first downstream channel to which a spread-spectrum spreader having a first spreading code is applied; one of ONUs receives the channel resource information block with a spread-spectrum despreader having the first spreading code and transmits a connection request to the OLT, using the carrier wavelength and the spreading code specified by the channel resource information block; the OLT having received the connection request transmits a new channel resource information block specifying a carrier wavelength and a spreading code to be used on an upstream data channel to the requester ONU through the first channel; and the requester ONU transmits data, using the carrier wavelength and the spreading code specified by the new channel resource information block.

Abstract: In a PON system, a PON-ID assigned to a connected ONU before replacement is assigned to a newly connected ONU after the replacement and, setting data before the replacement is succeeded also after the replacement. An OLT includes a PON-ID state where a management state of the PON-ID is stored, a PON-ID management table where the PON-ID and an ONU serial number of the connected ONU and setting data are correspondingly stored and, a delete ONU table where the PON-ID and an ONU serial number of a replacement object are correspondingly stored. When the OLT receives an ONU replacement instruction from an operation system, the PON-ID assigned to the ONU of the replacement object is assigned to an ONU newly connected during the ONU replacement.

Abstract: L2TP packet forwarding apparatus to be connected to at least two LACs (L2TP Access Concentrators) via L2TP sessions to receive packets transmitted from a gateway, which accommodates user terminals, in the form of a L2TP packet encapsulated in Bridge over PPP, has a lookup table indicating the correspondence of tunnel ID/session ID pairs to an identifier (VPN-IDs) of a wide area network to which a plurality of user terminals belong. The packet forwarding apparatus specifies an VPN-ID from the lookup table based on the tunnel ID and the session ID of a received packet and forwards, if it is confirmed that another tunnel ID/session ID pair associated with the same VPN-ID exists in the lookup table, the received packet to another L2TP session identified by the another tunnel ID/session ID pair in the form of a L2TP packet.

Abstract: A low-cost configuration of, and at the same time to control the variable dispersion compensator at a high speed in a variable dispersion compensator for compensating the wavelength dependent accumulated dispersion resulting from the wavelength dependency of the transmission fiber and fixed dispersion compensator in a long-distance high-speed WDM transmission system. In order to achieve the object mentioned above, the wavelength dependent representative characteristic of the transmission fibers 4-1 . . . n, and the wavelength dependent representative characteristic of the DCFs 13-1 . . . n are recorded and maintained in advance in the dispersion control circuit 5-1 . . .

Abstract: Part of an inputted optical add signal 118 is reflected by a mirror 117, and is thereby inputted into an optical wavelength multiplexer 105 in the reverse direction so that the optical add signal is returned to paths 115-1 through 115-16 corresponding to wavelengths ?1 through ?16. If the returned optical add signal is an optical add signal having a correct wavelength, the optical signal enters its corresponding backward direction optical detector 113-16. Accordingly, it is possible to check whether or not a wavelength of the optical add signal is correct.