Abstract: A DS-CDMA transmission method capable of improving the accuracy of channel estimation using pilot symbols by eliminating cross-correlation between pilot symbols inserted into code channels in CDMA multiplexing carrying out fast signal transmission. In each frame assembler, the pilot symbols, which are used for channel estimation for coherent detection, are inserted into coded information data on code channels at fixed intervals, and then the data is modulated by the modulator. The modulated data symbols in each code channel from the modulator are spread by the spreading modulator, the pilot symbols are spread using a spreading code, whereas the information symbols are spread using different spreading codes assigned to respective code channels. The spread signals of the code channels are summed up by the adder to be transmitted.

Abstract: A polishing composition comprising the following components (a) to (g):

Abstract: Achieving high speed spreading code synchronization of a forward link control channel. A control channel information signal and traffic channel information signals are each spread by different first spreading codes which are fed from a first spreading code (short code) generator (11), and which have a period equal to the period of an information symbol. Subsequently, only the control channel information signal is spread by a third spreading code which is fed from a third spreading code (long code masked portion complex conjugate code) generator (12), and which has a form of complex conjugate of a long code (second spreading code) used for spreading in common. The signals of the entire channels are summed up by an adder (13) at appropriate timings, and the resultant sum is spread by the second spreading code fed from a second spreading code generator (14), thereby being output as a spread modulation signal.

Abstract: A DS-CDMA transmission method capable of improving the accuracy of channel estimation using pilot symbols by eliminating cross-correlation between pilot symbols inserted into code channels in CDMA multiplexing carrying out fast signal transmission. In each frame assembler, the pilot symbols, which are used for channel estimation for coherent detection, are inserted into coded information data on code channels at fixed intervals, and then the data is modulated by the modulator. The modulated data symbols in each code channel from the modulator are spread by the spreading modulator, the pilot symbols are spread using a spreading code, whereas the information symbols are spread using different spreading codes assigned to respective code channels. The spread signals of the code channels are summed up by the adder to be transmitted.

Abstract: A RAKE receiver which is employed in a direct sequence spread spectrum communication system, and which can effectively receive multipath signals. A path searcher measures the amplitude of each path, selects N paths with larger amplitudes in descending order of magnitude, where N is the number of despreaders, and assigns the despreaders to the selected paths to despread the signals of the paths. This assignment of the despreaders to the paths is carried out such that a path with a large amplitude and a path with a small amplitude are assigned to adjacent despreaders and are input to the same pre-detection combiner. The outputs of the despreaders are combined by the pre-detection combiners, and detected by detectors whose outputs are RAKE combined by a post-detection combiner.

Abstract: A downlink transmission power control scheme for a mobile communication system using the site diversity, which carries out a primary downlink transmission power control using a primary control signal which is transmitted from the mobile station and terminated at each base station, and an additional downlink transmission power control using additional control signals which are transmitted from the base station control station to the base stations. The additional downlink transmission power control may also use a secondary control signal which is transmitted from the mobile station and terminated at the base station control station. The primary downlink transmission power control can be carried out during a non-site diversity period while the additional downlink transmission power control is carried out during the site diversity period, or the primary downlink transmission power control and the additional downlink transmission power control can be both carried out during the site diversity period.

Abstract: A variable rate transmission method that can vary the transmission rate of data. A transmitting side supplies a transmitted data sequence to an error detecting encoder 105 and a frame memory 103. The frame memory 103 stores data of a variable length to be transmitted in one frame. The error detecting encoder 105 calculates an error detecting code (such as CRC code) for each frame of the transmitted data. A multiplexer 104 adds the calculated error detecting code ahead of the transmitted data to place it at the initial position of the frame, and sequentially outputs the data sequence frame by frame. A receiving side calculates an error detecting code of the data in each transmitted frame in the same manner as the transmitting side, and compares the calculated error detecting code with the error detecting code at the initial position of the frame. The end bit of the frame data is decided as a position at which the two error detecting codes coincide.

Abstract: A coherent detection method including a step of estimating a transfer function of a propagation path using pseudo-pilot signals which consist of some information symbols adjacent to pilot signals. The information symbols in the pseudo-pilot signals are assumed to be known. The method includes the steps of estimating the transfer functions using the pilot signals, carrying out interpolation coherent detection of the information symbols using the estimated transfer functions, storing the detection results as the pseudo-pilot signals, reestimating the transfer functions associated with the information symbols corresponding to the pseudo-pilot signals by using the pseudo-pilot signals and the corresponding received signal under the assumption that the pseudo-pilot signals have a known correct pattern, and carrying out the interpolation coherent detection of the individual information symbols by using the transfer functions obtained by the reestimation.

Abstract: A repeater improving the effect of a RAKE reception. A received signal from a base station parallelly passes a first path including a first delay circuit and a second path including no delay circuit, and is transmitted to a mobile station. A received signal from the mobile station parallelly passes a third path including a second delay circuit and a fourth path including no delay circuit, and is transmitted to the base station. The delay time of the delay circuits are set at one chip interval or more of a spreading code. This forcedly produces multipath waves which are resolvable by a RAKE receiver. The RAKE receiver estimates amplitudes of desired wave components for individual delayed waves, performs weighting of the respective delayed wave components from detectors by using the estimated amplitudes, and makes symbol decision in terms of the combined weighted signal.

Abstract: A transmission power control method is disclosed for controlling transmission power of radio communications in a CDMA system. The transmission power of a first transmitted signal transmitted from a first station is determined by a transmission power control signal contained in a second transmitted signal sent from a second station. The first station receives the second transmitted signal in the form of convolutional codes, and decodes it by using a first Viterbi decoder and a second Viterbi decoder. The first and second Viterbi decoders includes path memories with the path history length of different first predetermined lengths. The transmission power control signal contained in the second transmitted signal is extracted from the output of the second Viterbi decoder, whereas the other information data is obtained from the output of the first Viterbi decoder. The first station controls the transmission power of the first transmitted signal on the basis of the extracted transmission power control signal.

Abstract: A code sequence generator having a register for holding n-bit code, and a calculation circuit for performing matrix calculation on the content of the register, and sequentially generating a code sequence by feeding back the calculation results to the register. The matrix which is set in the calculation circuit is changed by selectively reading a matrix from a memory circuit that stores precalculated matrices. This makes it possible to set a desired register state in a short time even if the desired code sequence is very long, and to generate any code sequences without changing the rate of a clock signal.

Abstract: A transmission power control method for a CDMA system including the steps of calculating an actual SIR (Signal-to-Interference Ratio) of a desired signal; deciding whether the actual SIR is greater than a predetermined reference SIR which satisfies a predetermined conununication quality; forming a transmission power control bit on the basis of a result of deciding; inserting the transmission power control bit periodically into a forward frame, which steps are performed at the base station, and steps of calculating tentative reverse transmission power in accordance with the transmission power control bit in the forward frame; deciding reverse transmission power such that the reverse transmission power is made equal to the tentative reverse transmission power when the tentative reverse transmission power is less than a predetermined maximum transmission power, but otherwise made equal to the predetermined maximum transmission power; and transmitting a signal from the mobile station to the base station at the re

Abstract: A gypsum composition for denture investment comprises 100 parts by weight of a mixture of 50-90 parts by weight of .alpha.-Gypsum hemihydrate (.alpha.-CaSO.sub.4.1/2H.sub.2 O) with 10-50 parts by weight of .beta.-Gypsum hemihydrate (.beta.-CaSO.sub.4.1/2H.sub.2 O) and 0.2-2.0 parts by weight of a soluble potassium salt and 0.5-3.0 parts by weight of mannitol. As the soluble potassium salt, use may be made of one or more of potassium sulfate, potassium chloride and potassium tartrate. The gypsum composition may further include 0.5-5.0 parts by weight of dihydrate gypsum.

Abstract: A method for strengthening dental restorative material is disclosed, which comprises depositing one or more inorganic salts of metals selected from rubidium, cesium, and potassium on the surface of a coated material of a dental restorative material obtained by coating and firing a dental porcelain fused to metal material. The dental restorative material is containing leucite and sodium on the surface of a dental alloy substrate, and heat treating the coated material at temperatures of 380.degree. C. or higher but lower than the melting point of the inorganic salt and the strain temperature of the coated material. According to the method of this invention, the coated material can be strengthened with ease while maintaining its translucency and color tone, without using any special device.

Abstract: A method for strengthened porcelain tooth is disclosed, which comprises depositing one or more inorganic salts of metals selected from rubidium, cesium, and potassium on the surface of a porcelain tooth obtained by sintering a dental porcelain material containing feldspar as a main raw material and sodium, and heat treating the porcelain tooth at temperature of 380.degree. C. or higher but lower than the melting point of the inorganic salt and the strain temperature of the porcelain tooth. According to the method of this invention, the porcelain tooth can be strengthened with ease while maintaining translucency and color tone as in a natural tooth, without using any special device.

Abstract: A gypsum composition for denture investment consists of 100 parts by weight of a mixture of 50-90 parts by weight of .alpha.-Gypsum hemihydrate (.alpha.-CaSO.sub.4.1/2H.sub.2 O) with 10-50 parts by weight of .beta.-Gypsum hemihydrate (.beta.-CaSO.sub.4.1/2H.sub.2 O) and 0.2-2.0 parts by weight of a soluble potassium salt. As the soluble potassium salt, use may be made of one or more of potassium sulfate, potassium chloride and potassium tartrate. The gypsum composition may further include 0.5-5.0 parts by weight of dihydrate gypsum.