Abstract: A base station has a first wireless communication unit that communicates with mobile stations for offering a first radio communication service to the mobile stations, and a second wireless communication unit that communicates with mobile stations for offering a second radio communication service that is different from the first radio communication service to the mobile stations. At the base station, a communication service continuation restrictor is provided that restricts operation of the base station as to whether or not, when it is detected that either one of the first or the second radio communication service is not executable, another radio communication service should be continued. Whether or not the other communication service should be continued can be set at the communication service continuation restrictor.

Abstract: A base station has a first wireless communication unit that communicates with mobile stations for offering a first radio communication service to the mobile stations, and a second wireless communication unit that communicates with mobile stations for offering a second radio communication service that is different from the first radio communication service to the mobile stations. At the base station, a communication service continuation restrictor is provided that restricts operation of the base station as to whether or not, when it is detected that either one of the first or the second radio communication service is not executable, another radio communication service should be continued. Whether or not the other communication service should be continued can be set at the communication service continuation restrictor.

Abstract: A modulation device, a demodulation device, and a transmission system and acoustic signal transmission method using them which can carry out a synchronization process for data signals without using a carrier frequency for a synchronization signal. The modulation device transmits an acoustic signal superposed with a PN sequence set according to a carrier frequency and a data signal. A demodulation device receives the acoustic signal, determines the PN sequence having the highest maximum correlation value with the acoustic signal in a plurality of PN sequences, detects a symbol synchronization point according to the correlation value between the thus determined PN sequence and the acoustic signal, and performs a synchronization process. Thereafter, according to the detected synchronization point and determined PN sequence, an OFDM demodulation processing unit decides the carrier frequency band of the data signal superposed on the acoustic signal and demodulates the data signal.

Abstract: In a proxy terminal or server a path setting can be performed by a server apparatus and a path setting that includes, as a relay point, a proxy terminal arbitrarily specified by a user or the proxy terminal located in a local network to which the user belongs, without adding any function to a user terminal. The proxy terminal includes a terminal group information generator unit configured to generate terminal group information that includes a user terminal identifier and a proxy terminal network identifier as a pair, and to transmit, to a server apparatus, the generated terminal group information.

Abstract: An object is to provide a modulation device, a demodulation device, and a transmission system and acoustic signal transmission method using them which can carry out a synchronization process for data signals without using a carrier frequency for a synchronization signal. A modulation device 3 transmits an acoustic signal superposed with a PN sequence set according to a carrier frequency and a data signal. A demodulation device 9 receives the acoustic signal, determines the PN sequence having the highest maximum correlation value with the acoustic signal in a plurality of PN sequences, detects a symbol synchronization point according to the correlation value between thus determined PN sequence and the acoustic signal, and performs a synchronization process. Thereafter, according to the detected synchronization point and determined PN sequence, an OFDM demodulation processing unit 38 decides the carrier frequency band of the data signal superposed on the acoustic signal and demodulates the data signal.

Abstract: In a proxy terminal or server a path setting can be performed by a server apparatus and a path setting that includes, as a relay point, a proxy terminal arbitrarily specified by a user or the proxy terminal located in a local network to which the user belongs, without adding any function to a user terminal. The proxy terminal includes a terminal group information generator unit configured to generate terminal group information that includes a user terminal identifier and a proxy terminal network identifier as a pair, and to transmit, to a server apparatus, the generated terminal group information.

Abstract: Likelihood calculating circuit A1 calculates the hamming distance between a received data series and a unique word as likelihood data d1. Likelihood calculating circuit A2 calculates the number of transmission errors using redundant data, and outputs this value as likelihood data d2. Likelihood data d1,d2 are added at adding circuit 21, and the output thereof is compared to the threshold value of determination circuit with threshold 22. The results of this comparison are output as determination signal with threshold DT. Synchronous determination circuit 23 generates a synchronous determination signal SD based on determination signal with threshold DT. Accordingly, the present invention provides a frame synchronization circuit in which it is possible to avoid out of synchronization or false synchronization, without increasing the amount of redundancy necessary to detect frame synchronization.

Abstract: A determinant, which represents the relationship between a sequence of code division multiplexed transmission symbol vectors b(k) from L communicators and a sequence of despread output vectors y(k) of received signals taking into account the cross correlation between spreading code sequences of transmitted signals, is limited within the range of .+-.g symbol duration about symbol timing k, and despread outputs of received signals within the limited range are inputted into a 2g+1-stage shift register. On the other hand, partial correlation matrixes R.sup.k+h (1), R.sup.k+h (0) and R.sup.k+h (-1) for each symbol duration within the limited range are calculated by a partial correlation computing part with respect to h=-g, . . . , g, then a correlation matrix R.sup.k between the spreading code sequences corresponding to the L communicators is derived from the partial correlation matrixes in an inverse matrix computing part and an inverse correlation matrix R.sub.k.sup.-1 of the correlation matrix is calculated.