Abstract: According to an aspect of an embodiment, a node apparatus used in at least part of nodes in a network formed by a plurality of nodes coupled in the shape of a ring, comprising: a working node function performing unit for performing functions as a working apparatus that selectively drops a frame destined for a terminal hosted by the node itself among frames transmitted on the ring and adds a frame from the terminal hosted by the node itself to frames transmitted on the ring; a back-up function performing unit for performing functions as a back-up apparatus that lets a frame destined for a terminal hosted by the node itself pass through to an adjacent node and discards a frame from the terminal hosted by the node itself; and a function selection unit for selectively enabling one of the working node function performing unit and the back-up function performing unit.

Abstract: An adaptive antenna radio communication device comprises a divided band direction estimating unit for estimating the direction by calculating the cross correlations between a pilot signal and sub-carrier signals of the respective divided bands received by an array antenna and calculating a spatial profile from correlation matrices determined by combining the correlation values between antenna elements of the different sub-carriers according to the output of the cross correlation calculation; a divided band array weight creating unit for creating a weight of a receive array having a directional beam in the direction of estimation for each divided band; and a sub-carrier directivity creating unit for creating a directivity by multiplication-combining the created receive array weight with the corresponding sub-carrier signal.

Abstract: An adaptive antenna radio communication device comprises a divided band direction estimating unit (4) for estimating the direction by calculating the cross correlations between a pilot signal and sub-carrier signals of the respective divided bands received by an array antenna (1) and calculating a spatial profile from correlation matrices determined by combining the correlation values between antenna elements of the different sub-carriers according to the output of the cross correlation calculation; a divided band array weight creating unit (5) for creating a weight of a receive array having a directional beam in the direction of estimation for each divided band; and a sub-carrier directivity creating unit (6) for creating a directivity by multiplication-combining the created receive array weight with the corresponding sub-carrier signal.

Abstract: A receiver having an array antenna estimates arrival directions of multiple paths that arrive with an angular spread. Consequently, arrival direction estimation accuracy can be ensured without increasing throughput even if the power every path is low by estimating an average arrival direction of an entire set of multiple paths having the angular spread from a result of one angular spectrum by multiple correlation operation units that perform mutual correlation operations with pilot signals for baseband signals received by the array antenna, a path detection unit that detects multiple arrival path receiving timings by generating a delay profile based on output of each of the correlation operation units, a path correlation value synthesis unit that synthesizes a correlation operation value calculated in the multiple correlation operation units and an arrival direction estimation unit that collectively estimates multiple path arrival directions using output of the path correlation value synthesis unit.

Abstract: A ring node device includes a main Resilient Packet Ring (RPR) card and a queued RPR card. Upon detection of disconnection of a communication link between the main RPR card and an L2/L3 switch, the ring node device exercises control to switch from the main RPR card to the queued RPR card and carries out communication with the L2/L3 switch.

Abstract: A receiver having an array antenna estimates arrival directions of multiple paths that arrive with an angular spread. Consequently, arrival direction estimation accuracy can be ensured without increasing throughput even if the power every path is low by estimating an average arrival direction of an entire set of multiple paths having the angular spread from a result of one angular spectrum by multiple correlation operation units that perform mutual correlation operations with pilot signals for baseband signals received by the array antenna, a path detection unit that detects multiple arrival path receiving timings by generating a delay profile based on output of each of the correlation operation units, a path correlation value synthesis unit that synthesizes a correlation operation value calculated in the multiple correlation operation units and an arrival direction estimation unit that collectively estimates multiple path arrival directions using output of the path correlation value synthesis unit.

Abstract: In a wireless communication apparatus adopting a time division duplex system for executing transmission and reception using a plurality of antennas, deviation of amplitude and phase occurring between transmission and reception circuits is detected and corrected using a communication signal. Channel estimation means 105 detects channel information based on reception output of reception circuits 104-1 to 104-N provided in a one-to-one correspondence with a plurality of antennas 101-1 to 101-N. Correction value detection means 110 finds a correction value for correcting deviation occurring between each of transmission circuits 103-1 to 103-N and each of the reception circuits 104-1 to 104-N based on the channel information. A wireless communication apparatus 100 transmits an already known signal (training signal) to a base station with which the wireless communication apparatus conducts communications.

Abstract: A radio communication apparatus using an array antenna has a plurality of reception branches for conveying reception signals received at the antenna element of the array antenna, and a calibration branch for selecting one of the plurality of reception branches and conveying the reception signal. Channel estimations are made respectively on the reception-branch signals and a calibration-branch signal. RAKE composition is made on the channel estimation values, a result of which is used to detect amplitude and phase deviations on the reception branch thereby carrying out a correction.

Abstract: An adaptive antenna base station apparatus comprises an array antenna including N (N being a natural number) antenna elements; N reception sections for respectively performing orthogonal detection of high-frequency signals, respectively received by the antenna elements, after frequency conversion; N×M despreading sections for performing despreading operations, corresponding to delay times of M (M being a natural number) path components included in output signals of the reception sections; M correlation computing sections for performing correlations among the antenna elements for each path; a correlation combining section for combining output signals of the correlation computing sections; and a DOA estimating section for estimating a direction of arrival (DOA) by using an output of the correlation combining section. This can ensure collective estimation of DOAs of M path components, thereby reducing the amount of computation of estimating the DOAs for plural paths and the cost for the apparatus.

Abstract: A path search circuit according to the present invention has an orthogonal multi-beam forming section 4 for directional reception with a plurality of orthogonal multi-beams orthogonal one to another, correlation-operating sections 61–6M for correlation-operating outputs of the orthogonal multi-beam forming section 4 with a known signal, weight multiplying sections 81–8Nb for multiplying the output of the correlation-operating section 61–6M by a weight converted into a beam space, delay profile generating sections 91–9Nb for generating delay profiles from the output signals of the weight multiplying sections 81–8Nb, and a path detecting section 10 for detecting a reception timing and arrival direction of arrival path from the delay profile. This path search circuit can enhance the accuracy of path direction detection by the use of a directional reception signal, and further reduce the direction dependence of path timing detection accuracy.

Abstract: A method of calculating coefficients determining excitation amplitudes and phases for obtaining a desired antenna pattern of a circular array antenna comprising a plurality of antenna elements disposed circularly. Coefficients for a linear array antenna having the same number of antenna elements as the circular array antenna are determined by a Fourier series expansion in integral limits calculated from a beam direction and a beam width that are estimated from incoming radio waves and then are transformed into the coefficients for the circular array antenna. With this method, the beam direction and the beam width of the antenna pattern of the circular array antenna can be set at will. Consequently, this method enables adaptive control of sectored beams of sectored antennas at a base station or the like used for a mobile communication system, thus enhancing efficiency of the use of the antennas.

Abstract: An SDH transmission apparatus including a low-speed part, a high-speed part, and a cross-connect part is disclosed. The low speed part includes a first signal transmission part and a second signal transmission part, each signal transmission part including an active transmission part and a standby transmission part. In the SDH transmission apparatus, an active transmission part of the first signal transmission part transmits a signal to a first transmission line via the high-speed part, an active transmission part of the second signal transmission part transmits a signal to a second transmission line via the high-speed part, and a standby transmission part of the first signal transmission part sends a part of signals supplied to the first signal transmission part to the second transmission line via the high-speed part when a traffic amount of the signals supplied to the first signal transmission part exceed a predetermined value.

Abstract: An adaptive antenna radio communication device comprises a divided band direction estimating unit (4) for estimating the direction by calculating the cross correlations between a pilot signal and sub-carrier signals of the respective divided bands received by an array antenna (1) and calculating a spatial profile from correlation matrices determined by combining the correlation values between antenna elements of the different sub-carriers according to the output of the cross correlation calculation; a divided band array weight creating unit (5) for creating a weight of a receive array having a directional beam in the direction of estimation for each divided band; and a sub-carrier directivity creating unit (6) for creating a directivity by multiplication-combining the created receive array weight with the corresponding sub-carrier signal.

Abstract: A network device provided with an Ethernet interface for interconnecting with another network device by auto negotiation, the network device comprising a link establishing function unit compulsorily establishing a link with the other network device and an on/off setting function unit setting the function of the link establishing function unit on or off and the link establishing function unit being comprised of a data transmission suppressing unit for suppressing the transmission of user data to the other network device until the sequence based on the auto negotiation is finished, whereby the problem of connectivity where the sequence of the auto negotiation repeats and no link can be established is solved.

Abstract: A transmission device includes a physical port and a plurality of logical ports that receive a control frame from a monitor/control device on in a network. The control frame includes an ID of a destination device and a control code. A communication controller in the transmission device appends to the received control frame, source port information (an ID of the physical port and an ID of the logical port at which the control frame is received), and local device information. If the control frame is meant for the local device, the communication controller carries out the process according to the control code in the frame. If the control frame is meant for a device other than the local device, the communication controller appends the source port information and the source device ID to the control frame and sends the control frame to the other device.

Abstract: An A/D converter converts the signal received by an array antenna and frequency-converted to a digital signal by a frequency converter. A correlation detector uses the chip rate as a cycle frequency and calculates a cyclic correlation matrix of spread spectrum signals stored in data storage. A cycle frequency detector detects the cycle frequency of an interference signal output from A/D converter. A correlation detector uses the detection result of the cycle frequency detector as a cycle frequency and calculates a cyclic correlation matrix of the signal, which becomes an interference signal, using the signal output from A/D converter. A direction of arrival is estimated, using the cyclic correlation matrices calculated by correlation detector and the correlation detector calculates the respective eigenvalues and eigenvectors and estimates the directions of arrival of a spread spectrum signal and a signal, which becomes an interference signal.

Abstract: A radio-wave arrival-direction apparatus calculates a correlation matrix of received signals by correlation calculation between antenna elements, and calculates a noise spatial eigenmatrix, of which each row or column is an eigenvector belonging to a noise eigen-space, by eigenvalue factorization of the correlation matrix. The apparatus also factorizes a matrix including a product of the noise spatial eigenmatrix and a conjugated and transposed matrix of it to an upper or lower triangular matrix, using cholesky factorization. The apparatus calculates an angle evaluation value in a predetermined angle range of an arrival-angle evaluation function using the derived upper or lower triangular matrix, and determines an arrival angle based on the calculation result. A calculation amount in a variable angle range can be thus reduced without causing accuracy degradation of arrival direction, in an algorism requiring all angle sweep for arrival angle estimation of MUSIC method or the like.

Abstract: A transmission weight computing section computes a transmission weight for directional transmission using an OFDM signal. A transmission correcting value memory section stores one correcting value for correcting the transmission weight for each sub-carrier of an OFDM signal or each band gathering a plurality of sub-carriers. A transmission weight correcting section corrects the transmission weight by the correcting value. A transmitting branch weights transmission data by a transmission weight outputted from the transmission weight correcting section on a sub-carrier-by-sub-carrier basis and delivers it to an antenna.

Abstract: A radio-wave arrival-direction apparatus calculates a correlation matrix of received signals by correlation calculation between antenna elements, and calculates a noise spatial eigenmatrix, of which each row or column is an eigenvector belonging to a noise eigen-space, by eigenvalue factorization of the correlation matrix. The apparatus also factorizes a matrix including a product of the noise spatial eigenmatrix and a conjugated and transposed matrix of it to an upper or lower triangular matrix, using cholesky factorization. The apparatus calculates an angle evaluation value in a predetermined angle range of an arrival-angle evaluation function using the derived upper or lower triangular matrix, and determines an arrival angle based on the calculation result. A calculation amount in a variable angle range can be thus reduced without causing accuracy degradation of arrival direction, in an algorism requiring an angle sweep for arrival angle estimation of MUSIC method or the like.

Abstract: An adaptive antenna base station apparatus comprises an array antenna including N (N being a natural number) antenna elements; N reception sections for respectively performing orthogonal detection of high-frequency signals, respectively received by the antenna elements, after frequency conversion; N×M despreading sections for performing despreading operations, corresponding to delay times of M (M being a natural number) path components included in output signals of the reception sections; M correlation computing sections for performing correlations among the antenna elements for each path; a correlation combining section for combining output signals of the correlation computing sections; and a DOA estimating section for estimating a direction of arrival (DOA) by using an output of the correlation combining section. This can ensure collective estimation of DOAs of M path components, thereby reducing the amount of computation of estimating the DOAs for plural paths and the cost for the apparatus.