Hitachi, Ltd.

Hitachi Communication Technologies, Ltd.

Kiyoshi Kawamoto

Shiro Mazawa

Akihiko Yoshida

Yosuke Takahashi

Keiji Usuba

Daigo Takayanagi

Mikio Kuwahara

Satoshi Masuda

Noboru Masuda

Toshiyuki Saito

May Suzuki

Manabu Kawabe

Tomoyuki Ono

Joichi Saito

A method for preventing or correcting the imbalance in load among interlaces in communications based on CDMA whereby communication resources are allocated to the respective interlaces through an interlacing scheme. A base station measures load information on an interlace-by-interlace basis, and notifies the same to a terminal while the terminal filters the load information to utilize the same for making a decision on transmission timing. Or the base station notifies the terminal of load information on plural transmission timings, and the terminal selects an adequate transmission timing to be then utilized. Otherwise, the base station presents at least two probabilities of transition between interlaces, urging the terminal to update an interlace (transmission timing) on a probabilistic basis.

Load balancing method for mobile communication system, base station and terminal

An AN (Access Network) controlled by a communication control apparatus and communicating with a AT Access Terminal), wherein the AN receives control information including information for allocating communication information from the communication control apparatus, and the AN transmits transmission cycle information for transmitting the communication information in a predetermined transmission cycle to the AT and allocates the communication information in the predetermined transmission cycle based on the control information received from the communication control apparatus to send the communication information to the AT.

Radio communication apparatus

A radio communication system including: ANs (Access Networks) for wirelessly communicating with an AT (Access Terminal); and a communication control apparatus for controlling the AN, wherein the communication control apparatus includes: a control unit for sending transmission cycle information and control information to the AN, and wherein the AN includes: a memory for storing information necessary for transmitting the communication information to the AT; a control unit for transmitting the transmission cycle information received from the communication control apparatus to the AT, calculating a transmission slot number necessary for sending the communication information in the transmission cycle, determining a transmission timing indicating a period in the predetermined transmission cycle allocated for the communication information, and transmitting the communication information in the determined transmission timing to the AT.

A wireless communication device for a communication system including data channels and control channels is disclosed. This device includes a receive section for receiving signals including data signals sent over the data channels, and control signals sent over control channels, the control signal corresponding to the data signals, a control channel demodulator for demodulating the control signals indicating at least one of the packet size and modulation method, a memory for accumulating the receive signals during the demodulation of the control signals, and a data channel demodulator for loading the receive signal from the memory, and demodulating the data signal according to the indicated at least one of the packet size and modulation method determined based on the demodulated control signals.

Baseband demodulation architecture for adaptive modulation method

A radio communication system includes a grouping unit for grouping a plurality of base stations into a plurality of groups (Soft Handoff Groups) and a determining unit for selecting base stations belonging to one and the same group selected from the groups produced by the grouping unit and for determining the base stations as base stations to send communication packets to an access terminal.

Radio communication system and base station

In a case where reception power in a radio access point is high by external noise, the normalcy of the radio access point is tested. In order to judge the normalcy of the radio characteristic of the radio access point, a test is performed through the calling connection between a testing access terminal in the radio access point and a predetermined device. An RSSI is measured before and after the transmission of a test signal. When the RSSI exceeds a threshold value, the path loss of a reverse link connected from the radio access point to the testing access terminal is increased by an attenuator. Then, reception power in the testing access terminal decreases. Thus, initial transmission power in accordance with the reception power from the testing access terminal is raised and the calling connection of the testing access terminal can be performed even under the external noise.

Radio access point testing apparatus

Admission control wireless resources including abase station which obtains a down wireless resource available rate based on a down QoS requested bandwidth Brequested by a terminal i during QoS communication and a data rate Rwhich the terminal can receive. A down wireless resource usage rate is obtained by dividing a down QoS requested bandwidth B requested by the terminal trying to perform QoS communication by the data rate R which the terminal can receive. An up wireless resource available rate is obtained based on ROT of an up channel and a threshold value Tindicating an allowable upper limit of the ROT. The QoS communication is performed on the terminal in which the up and down wireless resource available rates are respectively equal to or more than the up and down wireless resource usage rates.

Wireless communication system and base station

In order to realize such communication control as to reliably reconstruct communication information transmitted from a plurality of ANs at a plurality of ATs even when a BCMCS flow is added or deleted, a radio communication system includes a transmitter for transmitting control information necessary for the ATs to receive the communication information from a radio communication system at intervals of a predetermined period, and a controller for controlling to transmit a plurality of pieces of communication information to the ATs at intervals of a constant cycle and in synchronism with a transmission period of the control information.

There is provided admission control in view of wireless resources. A base stationobtains a down wireless resource available rate (available rate of slot allocation) based on a down QoS requested bandwidth Brequested by a terminal i during QoS communication and a data rate Rwhich the terminal can receive. A down wireless resource usage rate necessary to ensure the requested bandwidth B is obtained by dividing a down QoS requested bandwidth B requested by the terminal trying to perform QoS communication by the data rate R which the terminal can receive. The base stationobtains an up wireless resource available rate based on ROT of an up channel and a threshold value Tindicating an allowable upper limit of the ROT. Besides, an up wireless resource usage rate necessary to ensure an up requested bandwidth requested by the terminal is obtained. The QoS communication is performed on the terminal in which the up and down wireless resource available rates are respectively equal to or more than the up and down wireless resource usage rates.

A radio receiver handles a transmitted Walsh sequence having a code length of 'm' as a two-dimensional array of 'a' rows and &#x201c;b&#x201d; columns, and performs a fast Hadamard transform process having a code length of &#x201c;a&#x201d; in the row direction. The absolute values of the results are added in the column direction, and a Walsh number having the maximum receiving power is selected to determine a Walsh sequence having a code length of &#x201c;a.&#x201d; Then, only the identified column is extracted, and a fast Hadamard transform process having a code length of &#x201c;b&#x201d; is applied in the column direction.

Radio receiver

Disclosed is a transmission power control method which enables communications between a base station and a terminal station to be always performed at a high transfer rate by always assuring an uplink communication path between a base station which can transfer a downlink signal most efficiently and a terminal station. Each of terminal stationstoselects a base station which can receive a downlink radio wave with the highest power, and transmits a code for identifying the base station on an uplink signal. When the received power of the uplink radio waves transmitted from the terminal station which has transmitted the code identifying the own station is higher than the threshold value, each of base stationstotransmits a control signal for decreasing the power to the terminal station. When the terminal station sends a code for identifying another station or the power of the uplink radio waves received from the terminal station is lower than the threshold value, a control signal for increasing the power is sent to the terminal station. When even one power control signal for giving instruction to decrease the transmission power exists, each terminal station decreases its transmission power. When there is not the power control signal, each terminal station increases its transmission power.

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Yokohama, Japan

Kiyoshi Kawamoto