Abstract: The method of invention provides a multicast service from an information delivery apparatus to wireless terminals through wireless routes. The method includes the step of transmitting, from the information delivery apparatus, a plurality of sets of multicast information, wherein these sets are identical to each other as to contents thereof but differ in transmission conditions. The method further includes the step of receiving, at any given one of the wireless terminals, one of the sets of multicast information being transmitted under one of the differing transmission conditions.

Abstract: Formed on a dielectric substrate 11 are a center conductor 12 having a length L1 which is equivalent in electrical length to one quarter wavelength and ground conductors 13 disposed on the opposite sides of the center conductor with a gap portion therebetween in coplanar manner. The center conductor 12 and the ground conductors 13 located on the opposite sides thereof are connected together by shorting ends 14 resulting in forming corner areas, respectively whereby obtaining a coplanar waveguide resonator, wherein the edge line of the shorting end 14 is recessed to have an arcuate curve configuration so that each corner area has an angle of greater than 90° to reduce power current concentration at the corner points in the respective corner areas.

Abstract: An autonomous zone forming method of autonomously forming a zone which is a service area of a base station in a wireless communication system having the base station is provided. In the method, it is detected that a zone is newly formed around the base station, and a zone which is the service area of the base station is autonomously changed according to a newly formed zone. When determining the zone, receive quality of a signal received from a surrounding base station is used. In addition, a congestion state of a surrounding base station of the base station is detected, and a zone which is the service area of the base station is enlarged to the direction of the surrounding base station according to the congestion state.

Abstract: A power amplifier (1) for receiving and amplifying an input signal (10) and outputting an output signal (11) is disclosed. The power amplifier comprises: N power amplifying units (12) (N is an integer larger than 1) connected in parallel so as to output amplified signals in response to the input signal (10); an output combining unit (14) for combining the output signals from the N power amplifying units (12) and outputting a combined signal as the output signal (11) of the power amplifier; and an amplitude controlling unit (15) for selectively turning ON each of the N power amplifying units (12) based on an amplitude of the input signal (10).

Abstract: A mobile communication system includes a line control station, and a plurality of base stations belonging to a plurality of clusters so that each of the clusters includes a plurality of base stations. Each of the clusters includes a cluster control station which is connected to the line control station via a line and controls the base stations within the cluster to which the cluster control station belongs. In addition, each of the base stations within one cluster is connected to other base stations within the one cluster and/or the cluster control station within the one cluster via lines, so that each of the base stations within the one cluster is directly or indirectly connected to the cluster control station within the one cluster.

Abstract: A mobile communication system capable of determining a communication path to implement fast communication by multihop connection. The mobile communication system includes a mobile station, at least one relay station, and a base station and implements packet transmission from the mobile station to the base station through a communication path with an intermediary of at least one relay station or through a communication path without an intermediary of a relay station. The mobile communication system is provided with a communication path determiner for determining a communication path with a largest communication speed or a communication path satisfying a required line quality, based on interference levels of respective signals received at a relay station constituting a communication path between the transmitting station and the receiving station, and at the base station.

Abstract: A transmission signal and a pilot signal are predistorted by a digital predistorter 13 by use of a power-series model, and the predistorted output is converted by a digital-analog converter 14 to an analog signal. The analog signal is up converted by a frequency converter 15 to an RF-band signal, which is transmitted after being power-amplified by a Doherty amplifier 16. The pilot signal is extracted by a pilot signal extractor 17 from the output from the Doherty amplifier, and the extracted pilot signal is down converted by a frequency converter 18 to a baseband signal. The baseband pilot signal is converted by an analog-digital converter 19 to a digital pilot signal. A control part 21 detects an odd-order distortion component from the digital pilot signal, and based on the detected result, controls parameters of the digital predistorter.

Abstract: A location managing method for managing a location of a mobile station in a mobile wireless packet communication system in which each of communication nodes down to a base station have a hierarchical structure, wherein a route from a communication node positioned at a highest layer of the hierarchical structure to a base station of a cell in which a mobile station is located, is managed as location information of the mobile station, by being distributed to the communication node located at the highest layer of the hierarchical structure and to each of communication nodes in the route to the base station.

Abstract: A mobile communication system includes a plurality of base stations in a communication service area connected to a packet communications network. A mobile station communicates with a second station through the plurality of base stations and the network. The mobile communication system determines a virtual base station group as an aggregation of the plurality of base stations communicating with the mobile station, based on a condition of a radio transmission path between the mobile station and each base station, and combines information received by the plurality of base stations that belong to the virtual base station group at a base station included in the virtual base station group. The network connects the plurality of base stations non-hierarchically and the base station transmits combined information to the second station through the network relative to combined packets having the second station as a destination.

Abstract: A combined signal of a digital pilot signal and a digital transmission signal is applied to a digital predistorter (20), wherein it is added with odd-order distortions based on a power series model to generate a predistorted signal, then the predistorted signal is converted by a DA converter (31) to an analog signal, then the analog signal is upconverted by a frequency upconverting part (33) to a send frequency band, and the upconverted signal is output after being amplified by a power amplifier (37). A pilot signal component is extracted from the power amplifier output, then odd-order distortion components of the power series model are extracted by a digital predistorter control part (50) from the pilot signal component, and the odd-order distortions in the digital predistorter (20) are controlled to decrease the levels of the distortion components.

Abstract: The object is to implement autonomous and optimal cell formation on the occasion of adding a new resource to a cellular system. Abase station detects a location of its own, extracts location information about locations of neighbor base stations attached to broadcast signals from the neighbor base stations, captures the circumstances of the neighbor cell areas from these locations of its own and neighbor base stations, and sets a direction and a coverage (e.g., a cell radius and a spanning angle) of a new cell area on the basis of the circumstances of the neighbor cell areas. The base station may also be configured to capture the circumstances of the neighbor cell areas in consideration of propagation losses between the home station and the neighbor base stations, in addition to the above location information, or to capture the circumstances of the neighbor cell areas in consideration of the number of communicable base stations at a location of each mobile station in the neighborhood.

Abstract: The object is to control interference in a permissible range by applying the CDMA system to signal collision in the conventional CSMA and TDMA base multihop systems and to relax the hidden terminal problem and others to enhance the throughput of the entire system by grouping of channel groups in multihop transmission and by control of transmission based on an interference level from another station. A multihop relay station calculates a desired signal level, for example, from an interference level at its own station of a packet sent from a mobile station, and notifies the mobile station of the desired signal level; and the mobile station calculates a transmission power amount of a packet from the desired signal level, determines whether the packet is transmissible to the station as a source of the desired signal level, on the basis of the transmission power amount, and transmits the packet by a power of the transmission power amount to the source station determined as a packet-transmissible station.

Abstract: In a method and an apparatus of transmitting a burst signal when the burst signal is transmitted from a transmitting station to a receiving station at a transmission power value and/or a transmission rate determined in accordance with a state of a radio channel between the transmitting and receiving station in a mobile communication system, based on a comparison result between a criterion predetermined according to a state of the radio channel and/or a transmission waiting state of the signal, whether or not the burst signal is to be transmitted is determined, and, when it is determined that the burst signal is to be transmitted, the burst signal is transmitted from the transmitting station to the receiving station.

Abstract: A radio paging signal coding control scheme capable of improving the reception characteristic of the receiver by carrying out a coding control to determine logical channels for accommodating paging signals such that the transmission rate equivalently becomes as low as possible according to the paging signal traffic, without interrupting the paging signal coding processing while maintaining the combination of transmission rate and modulation scheme for frames, is disclosed. In the case of using prescribed transmission rate and N-valued modulation scheme, logical channels to be used for transmission of paging signals among a plurality of available logical channels are determined by setting priority orders among a plurality of available logical channels such that a number of states of modulated signals becomes less than N when paging signal traffic is small.

Abstract: The present invention is a network system of radio base stations comprising base stations provided in a plurality of cells and a control station controlling the base stations, in which the base stations and the control station are connected by optical fibers using a wavelength multiplexing transmission method, wherein: the base station comprises a variable-wavelength transmitter for transmitting an optical signal having a predetermined wavelength, and an optical coupler for combining optical signals from the variable-wavelength transmitter in order to transmit the optical signals using the wavelength multiplexing transmission method, the control station comprises a plurality of optical receivers for receiving wavelengths of the optical signals transmitted using the wavelength multiplexing transmission method, and an optical coupler for splitting the wavelength-multiplexed optical signals transmitted from the base stations into the optical receivers by wavelength, and when the radio communication terminal comm

Abstract: A packet transmission method in which packets are transmitted between a base station and a mobile station communicating with the base station includes the steps of: recognizing the size of each of the packets to be transmitted; determining a transmission rate for each packet in accordance with the recognized size of the packet; allocating a radio resource to the transmission of each packet between the base station and the mobile station based on the determined transmission rate; and transmitting each packet between the base station and the mobile station using the allocated radio resource. In the method, a modulation method or a radio resource used for transmitting the packets is determined by calculating a transmission rate in a wireless area according to the size of each packet and a transmission request in the wireless area.

Abstract: A data link transmission control method according to the present invention is a data link transmission control method of performing data link transmission control comprising automatic repeat request control for transmission/reception of a packet between a mobile station and a plurality of base stations, wherein when during connection with a first base station, the mobile station sends a request for connection with a second base station to the first base station, the first base station transfers data link transmission control information to the second base station.

Abstract: An information transmission system for transmitting information from a sending apparatus to a receiving apparatus is provided. The information transmission system includes: a sending apparatus for modulating an information signal, generating a plurality of signals including an optical signal from the information signal which is modulated, and transmitting the plurality of signals via a plurality of routes; and a receiving apparatus for receiving the plurality of signals from the sending apparatus, diversity-combining the plurality of signals, and outputting the information signal, in which the plurality of signals are a plurality of optical signals or signals including a radio signal.

Abstract: In transmitting/receiving optical beams including optical signals via a space transmission path between an optical transmitting apparatus and an optical receiving apparatus, a degree of spread of the optical beam emitted from the optical transmitting apparatus to the-optical receiving apparatus is varied according to a predetermined condition.

Abstract: In a radio resource allocation method of the present invention, use-state information of radio resources and priority information of mobile stations using the same radio resources of both a base station of concern and neighboring base stations is detected at the base station of concern. A new radio resource is allocated to a link between the base station of concern and a requesting mobile station in a cell site of the base station of concern based on the use-state information and the priority information of both the base station and the neighboring base stations.