Abstract: A multi-port apparatus used to communicably connect a computer and a plurality of apparatuses connected to the computer through the computer serial communication ports, such as two computer serial communication ports. A second serial communication port of the computer is connectable to ports corresponding to the plurality of apparatuses desired to be communicated with. A changeover switch is controlled through a first serial communication port of the computer to select one of the plurality of the apparatuses to connect with the second serial communication port of the computer and communicating with the one apparatus through the second serial communication port.

Abstract: A packet communications system which transmits a packet at a predetermined transmission rate includes a packet size controller configured to change a size of the packet in accordance with available space of a transmission buffer storing the packet, when the predetermined transmission rate is changed.

Abstract: There is provided a control device enabling switching of communication of a mobile terminal with one system to communication with another system while reducing power consumption and workload of the mobile terminal. The control device is used in a communication system including a first mobile communication system, a second mobile communication system, and a mobile terminal being in communication with the first mobile communication system. The control device comprises a position measuring unit for measuring the position of the mobile terminal, a judgment unit for making a determination whether or not to switch the communication of the mobile terminal from the first mobile communication system to the second mobile communication system according to a position measurement result of the position measuring unit, and a switching unit for performing the above switching operation according to the determination of the judgment unit.

Abstract: A transmission controller which controls downlink transmission rates of multiple communications terminals based on corresponding downlink transmission qualities of the communications terminals is disclosed. The controller includes a transmission-quality obtaining unit configured to obtain the downlink transmission qualities of the communications terminals. A communications-terminal selecting unit is configured to select out of the communications terminals one which has the need to change the downlink transmission rate in accordance with the downlink transmission qualities obtained at the transmission-quality obtaining unit. A transmission-rate changing unit changes the downlink transmission rate of the communications terminal selected at the communications-terminal selecting unit.

Abstract: The object of the present invention is to provide a radio communication system which can reduce control information transmitted from mobile stations to a base station, reduce traffic of up link radio resources, and suppress the quantity of interference to the entire radio communication system. The present invention relates to the radio communication system in which the same information is transmitted from a base station 30a to a plurality of mobile stations 40a to 40c with a predetermined down link transmission power. The base station includes transmission power controller configured to control the predetermined down link transmission power based on control information transmitted by a part of the mobile stations 40a to 40c subordinated to the base station 30a.

Abstract: The object of the present invention is to provide a communication system which makes it possible to avoid a control load from being generated while effectively utilizing the reception capabilities of mobile stations. The communication system includes a category manager 11 configured to categorize reception capability values showing reception capabilities necessary for receiving multicast data in the mobile stations, a reception capability collector 33 configured to collect the reception capability values of the mobile stations, a decider 34 configured to decide a hierarchical structure of the multicast data from a plurality of categories corresponding to the collected reception capability values of the mobile stations and a transmitter 31 configured to transmit the multicast data using the decided hierarchical structure.

Abstract: The object of the present invention is provide a mobile communication system which can reduce power consumption of a mobile station without increasing the number of times the data signals which are to be received by the mobile station are retransmitted. The base station 10 comprises a signal transmitter 11 configured to transmit the data signal a to the mobile station 30 within a predetermined period, and transmit each of retransmission signals a1 to a3 of the data signal a, in a form different from that of the data signal a, from the base station 10 to the mobile station 30 within the predetermined period A.

Abstract: The object of the present invention is provide a mobile communication system which can improve a communication quality of the mobile communication system as a whole by changing a transmission method for transmitting common information. Each of the mobile stations 200a to 200l comprises a communication quality measurer 230 configured to measure a communication quality of a signal transmitted from the radio station 100a.

Abstract: The object of the present invention is to make the most of reception abilities and radio resources of mobile stations 41 to 43, by determining transmission methods of transmitting information based on the reception abilities of the mobile stations 41 to 43 when the base station 40 performs multicast communication. The radio communication system according to the present invention has a reception ability value collector 42b, a transmission method determiner 42c, a transmitter 42a and a radio resource manager 42e. The reception ability value collector 42b collects a reception ability value of mobile stations 41 to 43 belonging to a multicast group A. The transmission method determiner determines a transmission method of transmitting information in accordance with the collected reception ability value. The transmitter 42a transmits the information to the mobile station 41 to 43 using the determined transmission method. The radio resource manager 42e manages available radio resources.

Abstract: A radio communication system includes a radio network controller, base stations and mobile stations. The mobile station includes a response signal transmitter which is configured to transmit a response signal including a group ID identifying a multicast group A to a base station. The response signal responds to a control signal for the multicast group A which the mobile station is joining in. The base station includes a response signal transmitter configured to transmit at least one response signal to the radio network controller. The response signal is selected from at least one response signal transmitted from the mobile station joining in the same multicast group A.

Abstract: A mobile communication system comprises: a determination unit configured to determine as to layers of data to be transmitted by base stations to mobile stations for respective radio areas, based on area resource information concerning radio resources for the respective radio areas covered by the base stations; and a radio transmitter configured to transmit the data to the mobile stations according to a determination of the determination unit.

Abstract: A communication system is disclosed that is capable of reducing data delay in transmitted hierarchized data and selecting predetermined data from the transmitted hierarchized data for communication according to conditions of the receiving end. The communication system includes a signal transmitting device that hierarchizes data to be transmitted and transmits the hierarchized data, and a signal receiving device that receives the data from the transmitting device. The signal transmitting device includes a hierarchized data transmitting unit that hierarchizes the data to be transmitted into a number of layers and transmits the data layers. The signal receiving device includes a layer identifying unit that identifies the data layers transmitted from the signal transmitting device, and a hierarchized data receiving unit that selects the identified data layers according to at least one of receiving capability and a propagating environment of the signal receiving device, and receives the selected data layers.

Abstract: A modulation device comprises a modulation unit (2) that modulates data in a hierarchical manner using multiple types of modulation techniques, and a transmission unit (3) that transmits the hierarchically modulated data. A demodulation device comprises a receiving unit (4) that receives the hierarchical modulation data having been subjected to hierarchical modulation using multiple types of modulation techniques, and a demodulation unit (6) that demodulates the hierarchical modulation data using a demodulation technique corresponding to a specific hierarchy of the hierarchical modulation data.

Abstract: The object of the present invention is to provide a radio communication system which can reduce the load on the radio network controller 50 during multicast communication, and a mobile station 11 and the radio network controller 50 which can be used in the above radio communication system. The radio network controller 50 comprises a control signal transmitter 50b configured to divide a multicast group into subgroups, to divide a control signal for the multicast group into control signals for the subgroups, and to transmit the control signals for the subgroups to the base station 10. The mobile station 11 comprises a response signal creator 11c configured to create a response signal to the control signals for the subgroups, a transmission timing detector 11d configured to detect a transmission timing from the control signals for the subgroups, and a response signal transmitter 11b configured to transmit the response signal to the base station 10 with the transmission timing.

Abstract: The object of the present invention is to provide a base station 10, a mobile station 11 and a radio network controller 50 which can reduce the load on the radio network controller 50 during multicast communication. The base station 10 supporting multicast communication comprises a response signal relay 10b configured to transfer response signals transmitted from a plurality of mobile stations 11, 12, 21, 41, 42 to a radio network controller 50. The response signals respond to a control signal for a multicast group. The response signal relay 10b transfers only a predetermined number of response signals to the radio network controller 50. Any following response signals are retained.

Abstract: A receiver of a mobile station or a base station in radio communications is formed by a correlation unit for generating a delay profile for specifying paths by taking correlations by using replica signals for a received pilot signal, and a path selection unit for comparing a power level of each path in the delay profile with a threshold determined according to an index value regarding a communication state, selecting paths for which a comparison result satisfies a prescribed condition as valid paths, and outputting a selected delay profile formed by the valid paths as a channel estimation value.

Abstract: A base station 1 according to the present invention is provided with a transmission power manager 2, a channel determiner 4, and a transmission power calculator 5. The transmission power manager 2 determines whether a total transmission power in a time slot N exceeds a maximum transmission power. When the transmission power manager 2 determines that the total transmission power in the time slot N exceeds the maximum transmission power, the channel determiner 4 determines whether there is a channel in which a transmission power can be decreased in the time slot N. When the channel determiner 4 determines that there is such a channel, the transmission power calculator 5 calculates a transmission power to be decreased in the time slot N in the channel.

Abstract: There is provided a radio communication device able to adaptively adjust a pilot symbol insertion rate and improve efficiency of channel estimation and data transmission. It comprises a channel estimation unit that performs the channel estimation using the pilot symbols, a storage unit that stores a plurality of estimated values obtained by the channel estimation unit, a determination unit that compares the estimated values stored in the storage unit and determines an amount of change of the estimated values, and a notification unit that notifies the pilot symbol insertion unit of the amount of change of the estimated values.

Abstract: A mobile phone 1 receives a home cell signal sent from a base station B1 and a foreign cell signal sent from a base station B2 or from a mobile phone 21 in a foreign cell A2. The mobile phone 1 receives spreading codes C2-C4 sent from the base station B1, as home cell codes. The mobile phone 1 detects the interference between the home cell signal and the foreign cell signal. When the interference is detected, the mobile phone 1 receives a spreading code C1 sent from the base station B2 or from the mobile phone 21, as a foreign cell code. The mobile phone 1 cancels an interference signal by joint detection, using the home cell codes and the foreign cell code.

Abstract: The present invention provides a radio base station using the conventional downlink transmit diversity which can compensate for the degradation of transmission quality even when a plurality of users (mobile terminals) share a single time slot using a code division multiple system. The radio base station includes a channel estimator 16 for performing channel estimation of an uplink time slot; a transmit diversity controller 141 to 14N for controlling the transmit diversity used for downlink time slots DL#1 to DL#N based on said channel estimation and the number of users sharing the downlink time slot when using a code division multiple system; a data transmitter 15 for transmitting data via downlink time slots DL#1 to DL#N using the controlled transmit diversity.