Nec Corporation

Nippon Telegraph and Telephone Corporation

Matsushita Communication Industrial Co., Ltd.

Noriaki Nagashima

Yoshitoshi Murata

Mitsuo Satoh

Mitsuo Sato

Susumu Kojima

Tadao Hashimoto

Toshihiko Shibata

Kohji Momma

Kohji Monma

The demodulator executes a demodulating process on a received radio signal, and generates a demodulation clock in the demodulating process. The first clock oscillator generates a high-rate clock which is at a high rate compared to the demodulation clock. The second clock oscillator generates a low-rate clock which is at a low rate compared to the demodulation clock. The timing generator estimates a rise time of the demodulation clock corresponding to the next reception timing in intermittent reception. Furthermore, the timing generator controls the first clock oscillators substantially in synchronism to the rise time of the demodulation clock.

Intermittent receiving system

When demodulating data of each frame of a phase-modulated signal received by a selected one of antennas, a phase error detector detects a phase error as a deviation from an ideal phase, and an accumulator accumulates phase errors in the frames. If an accumulated value of the phase errors is greater than a predetermined value in a predetermined slot position in a frame, antenna switching is controlled for a next frame. In the antenna switching control process, the demodulated phase of a first antenna selected in a present frame is held in a phase holder. If the accumulated value of the phase errors becomes greater than the predetermined value, the first antenna is switched temporarily to a second antenna, and the demodulated phase of the second antenna is held in the phase holder. Based on reception statuses of the first and second antennas, either better one of the antennas is selected, one of the demodulated phases held in the phase holder is selected and provided to a demodulator.

Apparatus for and method of antenna-switched diversity reception

Disclosed is a system for detecting non-coincidence of codes having a means for comparing an input coded signal and a predetermined coded signal to generate a non-coincidence signal including correct and error bits; a means for counting a number of the error bits included in the non-coincidence signal, thereby generating an error bit count signal for indicating the number of the error bits; and means for detecting non-coincidence between the coded signal and the predetermined coded signal by checking that the number of the error bits indicated by the error bit count signal is greater or equal to a predetermined error number.

System for detecting non-coincidence of codes

An input coded signal is compared with a predetermined coded signal to generate a non-coincidence signal. Error bits of the non-coincidence signal are changed to correct bits by a predetermined number of bits. When the non-coincidence signal has no longer any error bits as a result of changing the error bits to the correct bits, the input coded signal is determined to be correct.

For starting a registration operation of location information of movable radio telephone sets into a subscriber's file in a line connection unit connected to radio connection devices in a mobile telephone network system after travel of each of the radio telephone sets, each radio telephone set is provided with a unit for measuring a travel amount. The radio telephone set produces a request signal for the location information registration when the travel amount measured exceeds a first threshold value. Alternatively, the radio telephone set reset the measuring unit when the travel amount measured exceeds a first threshold value and thereafter produces a request signal for the location information registration when the travel amount measured does not exceed a second threshold value smaller that the first threshold value. Radio connection devices announce location information signals and each radio telephone set holds, as a held location information, the location information registered in the subscriber's file. When the telephone set receives one of the location information signals which has location information different from the held location information, the radio telephone set produces another request for registration of the different location information.

Location registration system enabling a radio telephone set to

In a microcellular cordless telephone network, radio speech channels are divided into several channel groups such that no intermodulation products occur among the channels of each group. In each microcell is located a base unit to which one of the channel groups is dynamically assigned. To achieve the channel assignment, each base unit generates priority values of the channel groups as representations of usage of the channel groups, consistently updates them through a statistical process and assigns one of the channel groups having a maximum priority value to the base unit.

Dynamic channel assignment cordless telecommunication network

In a network for serving cordless stations located in microcells, speech channels are divided into channel groups such that no intermodulation products occur among the channels of each group. Base units are located respectively in the microcell sites to establish two-way speech channels with their cordless stations. Each base unit generates and updates priority values of the channel groups as representations of usages of all channels through a statistical process. Depending on the updated priority values different channel groups are uniquely assigned to the base units. Timeslots are defined uniquely by the respective base units using the identifiers of the assigned channel groups for broadcasting zone-registration polling signals during the defined timeslots to elicit a zone registration response from each cordless station.

Cordless telecommunication network with dynamically assigned unique

In a cellular communications system, the quality of a signal transmitted over a first two-way connection from a mobile station via a first base station is compared with a threshold to determine whether a handoff is to be performed to a second, adjacent base station. When the quality of the transmitted signal becomes lower than the threshold, a second two-way connection is established from the mobile station to the second base station, and a switching request signal and an information-bearing signal are sent from the mobile station over both connections to a switching exchange. In response to the request signal, one directional path of the first connection is cleared to prevent a version of the signal passing through the first connection from reaching the destination station, and a first switching complete signal is sent through the other path of the first connection to the mobile station to allow it to clear the first connection and return a second switching complete signal. The other path of the first connection is then cleared in response to the second switching complete signal, leaving the second connection between the mobile station and the second base station.

Digital cellular switching system with means for securing uninterrupted

A wide area cordless telephone system covers a service area which is divided into a plurality of local areas to each of which belong a plurality of home position cordless telephones having multi-channel access capability. A plurality of access units are provided in each local area to define a plurality of access zones. A pre-dialing switching stage is provided for each local area to establish a connection between the access units and line terminals of a telephone switching system. Signals sent from any cordless telephone are received by a nearby access unit and applied to the pre-dialing switching stage. Each telephone transmits a registration request upon a manual command and, on receiving a response identifying a local area, returns an acknowlegement to identify the same local area as identified by the received response. On receiving a registration request, the pre-dialing switching stage transmits a response identifying the own local area through an access unit and assigns a reserved line terminal of the telephone switching system to a non-home position telephone if it is identified by the received request. On receiving an acknowledgement, the switching stage makes a registration of a telephone if the acknowledgement from it identifies the same local area as identified by the response.

Wide area cordless telephone system having means for avoiding double

A radio telephone system has a radio telephone set which has a receiving circuit the power of which is turned on or off in predetermined cycles, a radio connector transmit an ID number of the radio zone where it exists for a longer period than the period of turning on or off the power supply of the receiving circuit of the radio telephone set in predetermined cycles, the radio telephone set compares the ID number of the radio zone received with that stored in a memory, and when the ID numbers fail to coincide with each other, the ID number of the radio telephone set and the ID number of the radio zone received are transmitted as a position entry signal to a radio channel control unit through the radio connector, and the radio channel control unit being adapted to register the ID number of the radio telephone set and that of the radio zone.

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Tokyo, Japan

Noriaki Nagashima