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: 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 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 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.