Abstract: In a compressed mode, a spread spectrum communication device interleaves bit units across multiple frames using an interleaver, reduces the spreading factor using a framing/spreading unit, outputs the compressed mode frames at a predetermined compressed mode frame timing, and increases the average transmission power in the compressed mode at a radio frequency transmitter. Furthermore, a handover between different frequencies is carried out by establishing synchronization to another frequency carrier, based on a first search code and a second search code which have been detected, and moreover, a handover between different communication systems is carried out by establishing synchronization to a GSM, based on an FCCH and a SCH which have been detected.

Abstract: In a compressed mode, a spread spectrum communication device interleaves bit units across multiple frames using an interleaver, reduces the spreading factor using a framing/spreading unit, outputs the compressed mode frames at a predetermined compressed mode frame timing, and increases the average transmission power in the compressed mode at a radio frequency transmitter. Furthermore, a handover between different frequencies is carried out by establishing synchronization to another frequency carrier, based on a first search code and a second search code which have been detected, and moreover, a handover between different communication systems is carried out by establishing synchronization to a GSM, based on an FCCH and a SCH which have been detected.

Abstract: The communication system comprises a transmitter (1A) and a receiver (2A) . Both, the transmitter (1A) and the receiver (2A) are capable of operating in a normal mode or a compressed mode in which setting of a predetermined idle time is allowed. The transmitter (1A) effects transmission power control to a frame in each mode. When operating in the compressed mode, the transmitter (1A) changes a position of the idle time in such a manner so as to minimize adverse affect of a transmission power control error that occurs after the idle time.

Abstract: A spread-spectrum signal receiving method and apparatus in which a correlation operation is performed for obtaining a correlation between a base-band component of a received spread-spectrum signal and a spread code, so as to demodulate the received signal. In the method, a correlation operation between the spread code and the base-band component, and a correlation operation at a timing equal to a timing difference between the spread code and the base-band component in the former correlation operation step, the timing difference being 1/2 of a spread-code interval, are performed. Then, based on results obtained in these correlation operations, a correlation operation result at the timing point where a timing difference between the spread code and the base-band component is less than 1/2 of the spread-code interval, is estimated.

Abstract: Low rate data and middle rate data are time division multiplexed independently according to their rates by a time division multiplexer so that their rates match the rate of high rate data which are not passed through the time division multiplexer. Subsequently, the entire data are converted into biorthogonal signals by biorthogonal signal generators (BORTs), and code division multiplexed by a code division multiplexer. The code division multiplexed signal undergoes modulation by a spreading modulator and a carrier modulator, and transmitted.

Abstract: A data demodulator circuit for spread spectrum communication, presenting improved demodulation characteristics by allowing the elimination of the influence of a carrier offset remaining after down converting, and the removal of the interference caused by pilot signals with different timing. In-phase axis receive signal and operate with their respective reception timing of pilots signal. Phase difference information is extracted from the input signals and the signals are delayed to insure that the extracted phase difference information is equivalent to the average phase revolution. The influence of the carrier offset is eliminated by use of the extracted phase difference information. A data demodulator with canceler removes an interference I.sub.DF of pilot signals with different timing originating from the outputs of an interference amount calculator.

Abstract: A data demodulator of a receiving apparatus for spread spectrum communication for removing the phase difference remaining after detection for improving reception quality. In-phase and quadrature axis received signals are multiplied by pseudonoise codes PNI(t) and PNQ(t) and the results are averaged by averaging sections for calculating the correlation. By performing correlation processing, .rho.kO cos .theta., -.rho.O sin .theta., .rho.kO sin .theta., and .rho.kO cos .theta. are output when the amplitude of receive path signal is assumed to be .rho., the phase difference to be .theta., and a proportional constant to be kO. These signals are multiplied by in-phase and quadrature axis received signals and the results are added by adders, thereby removing the effect of the phase difference .theta.. The signal is used for data demodulation and data recovery circuit.

Abstract: An antenna selection decision system detects the level of the TDM burst immediately preceding to the TDM burst of the user's own channel and decides, on the basis of the detected level, to use the antenna selection diversity method or another selection criterion. When the other selection criterion is selected, the antenna which should receive the next TDM burst of the user's own channel is selected depending on the level of TDM burst of the user's own channel.