Abstract: A transmission apparatus including the number of antennas different from a reception apparatus and performing transmission by SC-MIMO to and from the reception apparatus includes a training signal generation unit that generates a known signal predetermined, a CP addition unit that adds a CP to each symbol of a transmission signal including the known signal, a weight generation unit that multiplies a channel matrix estimated based on the known signal by the reception apparatus by a pseudo-inverse matrix obtained by a predetermined number of iterative calculations to generate a transmission weight that is diagonalizable, and a transmission beam formation unit that uses the transmission weight to form a transmission beam for the transmission signal where the CP is added.

Abstract: A channel estimation method in which a reception device performs channel estimation on the basis of a known signal transmitted by a transmission device divides and arranges a known signal having a predetermined length in frames, transmits the known signal divided and arranged in the frames together with a data signal as a radio frame, receives the transmitted radio frame, calculates a data signal component including a delay wave component from the received radio frame, extracts a plurality of known signal components each including a delay wave component of the divided and arranged known signal by subtracting the data signal component from the received radio frame, concatenates the plurality of extracted known signal components to restore a known signal having a predetermined length, and performs channel estimation on the basis of the restored known signal having a predetermined length.

Abstract: An adjoint matrix adjH(z, t) of a transfer function matrix H(z, t) established between a transmission station and a reception station is defined as a transmission weight WT(z). A training signal multiplied by the transmission weight WT(z) is transmitted from transmission antennas toward a reception station. M sequence portions S included in the received training signals #1 and #2 are connected in series to generate a virtual training signal block. A communication path response R(m) implemented by using the transmission weight WT(z) is calculated by calculating a correlation between both an M sequence portion S and a comparison sequence portion at each position while sliding the comparison sequence portion with respect to the virtual training signal block. Based on the communication path response R(m), a reception equalization weight WR(z) corresponding to an inverse response det{H(z, t)}?1 of a determinant det{H(z, t)} of the transfer function matrix H(z, t) is calculated.

Abstract: An aggregation station: receives, from each of the base stations, communication path information with each of accommodated user terminals, for each user terminal; in a case where it is determined that the two of the base stations and the two user terminals are arranged on the straight line, generates first information for performing setting such that a transmission beam of any one of the base stations arranged on the straight line is stopped and another of the base stations non-orthogonally superimposes and multiplexes pieces of transmission data for the two respective user terminals with a predetermined power difference or power ratio; and controls the transmission beam of each of the two of the base stations arranged on the straight line on the basis of the first information.

Abstract: An aggregation station receives, from each of the base stations, communication path information with each of accommodated user terminals, for each user terminal; transmission weights of respective transmission beams transmitted by the plurality of the respective base stations are calculated such that the transmission beams transmitted by the plurality of the respective base stations arranged on the straight line to the plurality of respective user terminals are shifted by a half wavelength or more for the respective user terminals, on the basis of the communication path information for each user terminal received, in a case where it is determined that the plurality of the base stations and the plurality of user terminals are arranged on the straight line; and the base stations transmit the respective transmission beams on the basis of the respective transmission weights calculated.

Abstract: A wireless communication method in a wireless communication system which includes a radio transmitting station apparatus having a plurality of antennas and a radio receiving station apparatus having an antenna and which performs transmission and reception of a radio signal with a single carrier, the wireless communication method including: the radio receiving station apparatus or the radio transmitting station apparatus estimating a communication path matrix based on a training signal; the radio receiving station apparatus or the radio transmitting station apparatus transforming the communication path matrix into a frequency domain, calculating a pseudo inverse matrix for each frequency with respect to the transformed frequency domain communication path matrix, and transforming the calculated pseudo inverse matrix into a time domain and adopting as a transmission weight matrix; and the radio transmitting station apparatus forming a transmission beam based on the transmission weight matrix.

Abstract: A base station is wirelessly connected to each of a plurality of subscriber stations accommodating one or more terminals and includes a detection unit configured to detect at least one of a change in the number of terminals in communication accommodated by each of the subscriber stations and a change in a radio wave environment with each of the subscriber stations; and a setting unit configured to set a modulation scheme of a minimum modulation order in which a total communication amount of all the terminals that perform communication is accommodatable for each of the subscriber stations in each of the subscriber stations based on the change detected by the detection unit and to set weighting of radio wave intensity in each of the subscriber stations so that communication quality in the modulation scheme of the minimum modulation order is maximized.

Abstract: According to the present invention, in a wireless communication system that performs single carrier MIMO transmission between a transmitting station device and a receiving station device, the transmitting station device includes a time-domain linear equalization unit, a propagation path characteristics estimation unit configured to receive a training signal and estimate a transfer function matrix of propagation path characteristics, a filter tap calculation unit configured to calculate filter tap coefficients for the time-domain linear equalization unit based on the transfer function matrix by a predefined approach, and a transmission mode determination unit configured to make the filter tap calculation unit calculate the filter tap coefficients when the transfer function matrix meets a predefined condition, and to change a transmission mode and determine the transmission mode that meets the predefined condition when the transfer function matrix does not meet the predefined condition.

Abstract: A transmission device includes a training signal generation unit that generates a predetermined existing signal used for a receiving device to estimate a communication channel response and a transmission beam-forming unit that forms a transmission beam for removing interstream interference with a transmission weight calculated based on the communication channel response estimated by the receiving device. The receiving device includes a communication channel estimation unit that receives the existing signal and estimates a communication channel response, a combination unit that combines a plurality of communication channel responses for each stream estimated with the existing signal from which the interstream interference has been removed, and an equalization unit that performs an equalization process of removing intersymbol interference for each stream with the reception weight calculated based on the communication channel responses combined by the combination unit.

Abstract: According to the present invention, in a wireless communication system that performs single carrier MIMO transmission between a transmitting station device and a receiving station device, the transmitting station device including: a time-domain linear equalization unit configured to remove inter-symbol interference and inter-stream interference from a data signal to be transmitted to the receiving station device; a propagation path characteristics estimation unit configured to receive a training signal which is transmitted by the receiving station device and estimate a transfer function matrix of propagation path characteristics; and a filter tap calculation unit configured to calculate filter tap coefficients for the time-domain linear equalization unit by representing the estimated transfer function matrix as a matrix polynomial, taking an inverse response of the matrix polynomial as a transmit weight matrix, and approximating the transmit weight matrix with Neumann series, and the receiving station device

Abstract: Provided is a wireless communication system configured to accommodate a plurality of circuits to transmit a signal from a transmitter to a receiver, the system including a number-of-circuits observation unit configured to observe the number of circuits among the plurality of circuits through which communication is being performed; a quality observation unit configured to observe a quality of each of a plurality of communications; a determination unit configured to determine a modulation scheme for transmitting a signal based on the number of circuits observed by the number-of-circuits observation unit, the quality of each of the plurality of communications observed by the quality observation unit, and a required throughput of each of the plurality of circuits; and a modulation unit configured to modulate the signal using the modulation scheme determined by the determination unit.

Abstract: A congestion control method in an IP telephone system includes acquiring a number of simultaneous calls in one line shared by a plurality of IP telephones, acquiring a call time order corresponding to length of a call time for each call, and controlling a packet discard rate of each call on the basis of the number of simultaneous calls and the call time order. The packet discard rate of each call is set to a predetermined first upper limit value or less. In addition, the packet discard rate is set higher as the call time is longer, and the packet discard rate is set lower as the call time is shorter. Further, the packet discard rate of the latest call having the shortest call time is set to be equal to or less than a predetermined second upper limit value lower than the predetermined first upper limit value.

Abstract: Provided is a software wireless device capable of continuing communication without being affected by quality deterioration of a wireless line and without discarding of traffic data. The data to be transmitted is duplicated and wirelessly transmitted over a plurality of communication lines having different frequency bands (step 104). The received data received by the communication line having the best line quality is validated. Another frequency band that is different from the frequency band used in the plurality of communication lines and can provide line quality exceeding a determination criteria is searched (step 106). When the quality of the communication line communicating the same data deteriorates (step 108), the communication on that line is switched to the wireless communication on the additional communication line using the other frequency band (step 110).

Abstract: To avoid uniform deterioration of the voice quality of all the calls sharing an IP phone line at a time of congestion. The congestion control method in an IP phone system includes a call state acquisition process of acquiring the number of simultaneous call sessions in one line shared by a plurality of IP phones. A congestion control method further includes a packet loss control process of setting a priority ranking to each call session and dynamically controlling packet loss rates of the call sessions in accordance with the number of the simultaneous call sessions and the priority ranking. In the packet loss control process, the packet loss rate is set lower for call sessions ranked higher in priority, and higher for call sessions ranked lower in priority.

Abstract: A transmitting station device at least comprises a training signal generation unit, and a receiving station device at least comprises a communication path estimation unit which estimates a communication path response from the known signal, and a beam forming unit which performs a beam forming process using a weight to suppress inter-stream interference, a channel fluctuation amount calculation unit which calculates as a channel fluctuation amount a difference between the communication path responses estimated in a manner of one following another in time, and a weight calculation unit which calculates a new weight using an updated value of the weight calculated based on the channel fluctuation amount are included in one of the transmitting station device and the receiving station device. This can significantly reduce the amount of calculation related to update of a weight.

Abstract: A wireless communication method in a wireless communication system which includes a radio transmitting station apparatus having a plurality of antennas and a radio receiving station apparatus having an antenna and which performs transmission and reception of a radio signal with a single carrier, the wireless communication method including: the radio receiving station apparatus or the radio transmitting station apparatus estimating a communication path matrix based on a training signal; the radio receiving station apparatus or the radio transmitting station apparatus transforming the communication path matrix into a frequency domain, calculating a pseudo inverse matrix for each frequency with respect to the transformed frequency domain communication path matrix, and transforming the calculated pseudo inverse matrix into a time domain and adopting as a transmission weight matrix; and the radio transmitting station apparatus forming a transmission beam based on the transmission weight matrix.

Abstract: In a wireless communication system in which propagation delays between a plurality of terminal station devices and a base station device, which use time division multiplexing in a duplex operation system, are different from each other, at least one of the base station device or the terminal station devices includes a delay calculating unit that calculates the propagation delay for each of the terminal station devices, and the base station device includes a control unit that changes a frame configuration such that a standby time required for switching between an uplink frame and a downlink frame is shortened in accordance with the propagation delay for each of the terminal station devices. In accordance with this, a surplus standby time can be shortened, and a transmission capacity can be improved.

Abstract: In a wireless communication system in which there is a propagation delay between a terminal station device and a base station device using time division multiplexing in a duplex operation system, at least one of the base station device or the terminal station device includes a delay calculating unit that calculates a propagation delay, and the base station device or the terminal station device includes a control unit that changes a frame configuration such that a standby time required for switching between the uplink frame and the downlink frame is shortened in accordance with the propagation delay. In accordance with this, a surplus standby time is shortened, and a transmission capacity can be improved.

Abstract: A wireless quality degradation factor detection method according to an embodiment includes a spectrum generation step of generating a spectrum based on a received radio wave, a determination step of determining whether or not information based on the generated spectrum contains a factor that prevents maintenance of the quality of the received radio wave based on a determination criterion specified in advance, an identification step of identifying the factor that prevents maintenance of the quality of the received radio waves based on the result of the determination and the determination criterion, and an output step of outputting information representing the identified factor.

Abstract: A wireless communication device includes an estimation observation unit that observes a channel condition by estimating a tendency of a long delay wave and a channel fluctuation from a received signal in which a training signal is added to a data frame, a first equalizer that compensates for the received signal, a second equalizer that compensates for the received signal with a property of having a higher long delay wave tolerance and a lower channel fluctuation tolerance than the first equalizer, and a control unit that performs control which switches such that the first equalizer or the second equalizer performs compensation for the received signal, on the basis of the channel condition observed by the estimation observation unit.