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: A wireless communication method according to one embodiment includes: dividing the plurality of user signals into a plurality of frequency channels of an active system; distributing the plurality of divided user signals to the plurality of frequency channels of the active system; transmitting the plurality of user signals distributed to the plurality of frequency channels of the active system for each of the plurality of frequency channels of the active system; switching a frequency channel of the active system in which an abnormality occurs to a frequency channel of the redundant system when the abnormality occurs in one of the plurality of frequency channels of the active system in which the plurality of user signals are transmitted; receiving the plurality of transmitted user signals for each frequency channel; and combining the plurality of user signals received for each frequency channel as a plurality of user signals for each user.

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 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; 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: An Internet Protocol (IP) phone system includes a traffic control device connected to a line. The traffic control device acquires a call duration of each of calls on one line shared by a plurality of IP phones, and sets a packet discard rate of each of the calls in a manner where the packet discard rate is proportional to the call duration until start of a new call so that total call traffic falls within a line capacity of the one line when the total call traffic exceeds the line capacity with the start of the new call.

Abstract: A signal transmitted by a transmission device is converted into a signal of another frequency having a bandwidth equal to or greater than that of the transmission device, the signal obtained by converting the frequency is divided into signals of a plurality of frequency bands, signals of one or more frequency bands having high priorities are specified among the divided signals of the plurality of frequency bands, the signals are duplicated as signals of other frequency bands, the divided signals of the plurality of frequency bands and the duplicated signals of the other frequency bands are wirelessly transmitted, the transmitted signals are wirelessly received, signal combination is performed to reproduce the converted signals of the other frequencies using the received signals, and the combined signals are converted into a signal with a predetermined frequency.

Abstract: A wireless communication method according to an embodiment includes converting n+1 signals into n predetermined power signals obtained by setting a C/N to a predetermined value and into n divided signals obtained by setting the C/N to 1/n of a predetermined value and performing division into n, superimposing the n predetermined power signals and the n divided signals that have been converted, non-orthogonally so as to be n multiplexed signals for the n frequency channels, transmitting the n multiplexed signals, receiving n multiplexed signals, demodulating n predetermined power signals from the n multiplexed signals that have been received, creating replica signals of each of the n predetermined power signals, subtracting each of the n replica signals that have been created from each of the n multiplexed signals, and combining the n subtracted signals.

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: A radio system maintenance support device supports maintenance of radio system. System status information indicates at least one of radio communication status and device status of radio device in the radio system. Anomaly situation information indicates anomaly situation in the radio system. Failure analysis result information indicates at least one of failure location in the radio system and maintenance action required for the failure location. A failure analysis model is a trained model receiving at least the anomaly situation information and outputting the failure analysis result information, which is generated by learning based on past anomaly situation information and past failure analysis result information. The radio system maintenance support device analyzes the system status information to acquire the anomaly situation information.

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: A congestion control method in an IP telephone system includes processing of acquiring the number of simultaneous calls on one line shared by a plurality of IP telephones, processing of acquiring lengths of call duration of respective calls, and communication parameter setting processing of setting communication parameters that contribute to communication quality of respective calls on the basis of the number of simultaneous calls and the call duration. The call duration of the first call is longer than the call duration of the second call. The communication parameter setting processing includes processing of setting communication parameters such that the communication quality of the first call is worse than the communication quality of the second call in a case where the number of simultaneous calls exceeds a threshold value.

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 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.