Abstract: The present invention is directed to a TDMA communication system which is adapted to different communication environments or prepares different communication environments and allows each mobile station to be set for working in any one of the different communication environments. The communication system commonly uses a TDMA format that has a fixed frame-length and a constant number of bits for each of the slots composing the frame. The communication environments have prepared respective sets of communication conditions, each set including a transmission power, a modulating method, the number of multiplexed signals, error-correction, an antenna gain, a frequency hopping value and a diversity value. At each mobile station and each base station, one of plural sets of communication conditions for respective environments is selected to establish communication with each other under the selected environment.

Abstract: An improvement of an ATM transmission system between a mobileservices switching center and a base station in a mobile communication system. A delay time for generating/sending out a cell is minimized to ensure the information quality required for real time transmission. When the transmission interval of a call type a is T, call types b and c whose periods are twice and four time that of the call type a should be transmitted at intervals twice and four times that of the call type a. A transmitted frame assembler/disassembler 104 in the base station prepares transmitted frames 201 each including the cell slots 201-1, 201-2 and 201-3 for transferring the respective call types, and schedules such that the transmitted frames are sent out to a channel 112 at the interval T, thereby enabling the transmission to be carried out without delay.

Abstract: A signal reception apparatus for DS-CDMA communication system having a complex matched filter for despreading a received signal into I- and Q-components Di and Dq of despread signal. Dj and Dq are input to a path selection portion 13 for extracting a phase error in a pilot symbol block of the despread signal. A phase compensation signal is calculated according to the phase error in the portion 13. An information symbol is compensated according to the phase compensation signal. An electrical power is calculated from an average of the phase compensation signal of several slots for selecting paths to be received. The selected paths are combined with phase synchronized by a rake combiner 14.

Abstract: In a communication system, a communication control apparatus is disposed in a mobile object. The communication control apparatus relays information exchanged between a plurality of radio terminals carried into the mobile object and a network side. The communication control apparatus comprises a communication control server which performs establishment of a radio channel between it and a base station at the network side, and establishment of a radio channel between it and a radio terminal according to a communication request from the radio terminal, and a communication unit which performs a radio communication with the radio terminal and a radio communication with the base station, using each radio channel established by the communication control server.

Abstract: An improvement of an ATM transmission system between a mobileservices switching center and a base station in a mobile communication system. A delay time for generating/sending out a cell is minimized to ensure the information quality required for real time transmission. When the transmission interval of a call type a is T, call types b and c whose periods are twice and four time that of the call type a should be transmitted at intervals twice and four times that of the call type a. A transmitted frame assembler/disassembler 104 in the base station prepares transmitted frames 201 each including the cell slots 201-1, 201-2 and 201-3 for transferring the respective call types, and schedules such that the transmitted frames are sent out to a channel 112 at the interval T, thereby enabling the transmission to be carried out without delay.

Abstract: A digital modulation and demodulation scheme for radio communications which is capable of reducing errors due to fading while maintaining the characteristic of the M-ary modulation and demodulation scheme that it is robust against interferences. At the transmitting side, transmission data are divided in advance into blocks of LN bits length each and each block is divided into N sets of L bits data sequences. Then, orthogonal codes of M bits length each corresponding to L bits codes given by the L bits data sequences are generated, and N sets of orthogonal codes for each block are multiplexed into a multiplexed signal, such that M bits constituting each orthogonal code are dispersed in time in the multiplexed signal. A digital modulation is then applied to a carrier using the multiplexed signal.

Abstract: An error rate of received signal is measured by a received signal error measuring unit 32, and a target SIR is changed by a target SIR decision unit using the error rate. It is also possible to detect error rate of received signal in an unit of frame using a CRC signal of a frame. It is further possible to detect error rate of received signal by detecting errors of known pilot signals inserted in a constant interval.

Abstract: A method of frequency utilization in mobile communication which is capable of realizing efficient frequency utilization in the case where widths of the uplink communication frequency bandwidth and the downlink communication frequency bandwidth are different in mobile communication is disclosed.

Abstract: The outputs of antenna elements 111 to 11M of a wide directional pattern 12 are distributed by a distributor 13 to respective channel parts 141 to 14N, and in each channel part 14i (i=1, 2, . . . , N), its connection points 311 to 31M to the distributor 14 are divided in groups of P=4; four connecting ends of the respective groups are connected via level-phase regulators 231to 234 to combiners 221 to 22L (L=M/P), then the combined outputs therefrom are applied to receivers 151 to 15L, and the outputs therefrom are combined after being applied to regulators 161 to 16L which are adaptively controlled.

Abstract: In a distortion injection path (15) wherein a detected distortion component of a main amplifier (23) becomes amplified, distortion by an auxiliary amplifier (29a) is detected by an auxiliary distortion detector (42) composed of a variable attenuator (27a), a variable phase shifter (28a), a first auxiliary amplifier (29a), a delay line (36) and a phase inverter (37), and the detected distortion is cancelled by an auxiliary distortion canceller (43) composed of a variable attenuator (27b), a variable phase shifter (28a), a second auxiliary amplifier (29b) and a delay line (39), thereby increasing the efficiency of the amplifier.

Abstract: A mobile communication system which is capable of supporting multiple simultaneous communications on a single mobile terminal device, and collectively controlling all or a part of call states on a mobile terminal device. The system includes at least one mobile terminal device having: more than one mobile terminal side call control units for controlling calls at a mobile terminal side; and a mobile terminal side mobile terminal management unit for managing a communication state of the mobile terminal device while identifying each mobile terminal side call control unit which is currently in communication.

Abstract: A perch channel transmission and cell selection method for a CDMA mobile communication system which is capable increasing a system capacity by reducing an amount of interference power. In this method, each base station intermittently transmits a perch channel which is spread by using a spread code assigned to each base station. Then, a mobile station receives more than one perch channels transmitted from more than one base stations, measures a receiving level of an intermittently transmitted portion of each received perch channel, and judges a located cell according to measured receiving levels of these more than one perch channels.

Abstract: Control of a packet communications network in a fixed network used by a mobile communications network is performed. (1) A communication hold mode is set for a user when the traffic volume of the user's transmission or reception of a packet per fixed time period is less than a predetermined value. The communication hold mode is defined as “although the network resources are released once, a mobile station and a gateway center at an interface with an external network behave to the user side and the external side as though the communication hold mode were maintained”. (2) When the user in the communication hold mode restarts the transmission of a packet, the mobile station automatically carries out a recall processing without the intervention of the user, and re-establishes the communication up to the gateway carrier.

Abstract: A CDMA communications system that can shorten a delay time until the establishment of traffic, and prevent excessive transmission power. Although transmission request signals RQ1, RQ2, RQ3, . . . sent from mobile stations through a common channel undergo only open loop power transmission control, and hence have large fluctuations in their received levels, their interference amount to message signals can be kept low because their received power is averagely about 1/a of that of the message signals MSG1, MSG2, MSG3, . . . The message signals are sent from the mobile stations in accordance with the power transmission control bits contained in a forward link signal ACK sent from the base station, followed by closed loop power transmission control. This enables the received level fluctuations at the base station to be kept low.

Abstract: A synchronization equipment performs correlation processing between a first known pattern included in a received signal and a second known pattern, and detects reception timing of the received signal. A correlation value computing portion computes a correlation value between the first known pattern and the second known pattern at every reception time. A reception timing detection portion compares the computed related value with a predetermined threshold value, determines the reception time when the correlation value becomes larger than the threshold value to be the reception timing of a received signal, and, after this determination, suspends the comparison between the correlation value and the threshold value, and holds the reception time determined to be the reception timing.

Abstract: A signal reception apparatus in the spread spectrum communication system requires only a small amount of circuitry and consumes a small amount of electric power. A quadrature detector decomposes received signals into in-phase components and quadrature components, and supplies them to a complex-type matched filter. The complex-type matched filter de-spreads the in-phase components and the quadrature components and sends them to a multi-path selector. The multi-path selector selects, from among the received de-spread signals, multiple paths having high levels of signal electric powers and sends the received signals of the selected paths to multiple phase correction blocks. Analog operation circuits calculate phase errors of the received signals of two successive pilot symbol blocks for each path. An analog operation circuit corrects the phases of the received signals of the information symbol block that has been received between the two successive pilot symbol blocks.

Abstract: A handover type judgement scheme for a CDMA mobile communication system which is capable of judging an appropriate type of handover from multiple types of handover available. At the mobile station, one type of handover for which a handover start condition is weakest among available types of handover is judged. Then, whether the handover start condition for that one type of handover is satisfied or not is checked, and each base station for carrying out that one type of handover is notified when the handover start condition for said one type of handover is satisfied.

Abstract: In a radio transmission amplifier unit which has between input and output terminals a gain-controlled amplifier 11, a pre-amplifier 12 connected to the output thereof and a main amplifier 13 supplied with the output therefrom, the range of the transmitting power level is divided into small, medium and large regions.

Abstract: A subscriber information storing module is fixedly and internally housed within a mobile station, which is provided with an interface which permits an IC card storing subscriber information to be loaded. When a power supply is turned on, if a module is not loaded into the interface, subscriber information in the internally housed module is used to perform an activation processing for the mobile station. When an IC card is loaded into the interface, an examination is made to see if the subscriber number of the IC card and the subscriber number of the mobile station coincide, and if they coincide, the internally housed module is disabled, and subscriber information of the IC card is used.

Abstract: Received baseband signals from a plurality of antennas 111 to 11Q are linearly combined through multiplication by weighting coefficients, then a decision signal is delayed for one symbol duration, and the delayed signal is multiplied by a feedback filter coefficient wb* to generate intersymbol interference, which is subtracted from the linearly combined output y(i). The subtracted output is subjected to a signal decision to obtain a decision signal, then the difference between the input into a decision unit 17 and the decision signal is obtained as an error signal e(i), and weighting coefficients w1* to wQ* and the feedback filter coefficient wb* are estimated in a parameter estimation part 71 so that the square of the error signal e(i) is minimized.