Ntt Docomo, Inc.

Ntt Mobile Communications Network, Inc.

Hidehiro Ando

Yukihiko Okumura

Masafumi Usuda

Takuya Sato

Hiroyuki Ishii

Yoshihiro Ishikawa

Seizo Onoe

Takehiro Nakamura

Takahiro Hayashi

Mamoru Sawahashi

Kenichi Higuchi

Mikio Iwamura

Anil Umesh

Takaaki Sato

Masafumi Masuda

Yoshiyuki Yasuda

Shinya Tanaka

Yoshinori Miki

Kouji Makino

Shinichi Sasaki

Disclosed is a communication method for switching between a first connection state, in which a data unit is transmitted in a first size, and a second connection state, in which a data unit is transmitted in a second size which is larger than the first size. The communication method comprises a step of maintaining the size of a data unit at the first size in a case where there is a transition from the first connection state to the second connection state after there had been a transition from the second connection state to the first connection state.

Communication method, communication system, and control apparatus

A radio network controller includes: a determination unit configured to determine a transmit diversity method to be used to transmit a signal from a base station to a mobile station, in accordance with a soft handover status of the mobile station; and an instruction/notification unit configured to instruct the transmit diversity method to the base station, in accordance with the determination result by the determination unit.

Radio network controller, base station, mobile station, mobile communication system and mobile communication method

In this invention, a channel estimation value of data symbols of a data channel is calculated by weighting and averaging pilot symbols in a parallel time multiplexing method. Also, a channel estimation value of data symbols during each data symbol interval is calculated by dividing data symbols in a slot into a plurality of data symbol intervals, selecting pilot symbols suitable for calculation of a channel estimation value of data symbols during each data symbol interval and weighting and averaging that pilot symbols. Also, a fading frequency is detected based on an inner product value of pilot symbols. Weighting factors are changed based on the detected fading frequency. Also, a channel estimation value is calculated by weighting and averaging pilot signals using a plurality of weighting sequences. The calculated channel estimation value is used to demodulate received data. The output data with the highest quality is selected by judging reliability of these plurality of demodulated data. It is also possible to select some weighting sequences based on the result of the reliability judgment of the demodulated data for predetermined period of time. In this case, after the selection, demodulation is performed by using these selected weighting sequences only.

Channel estimation device and method, demodulation device and method, and fading frequency decision device and method

A reception device for use in a mobile communication system having a mobile station and a radio base station to which transmission diversity for transmitting transmission signals using a plurality of antennas is applied in a downlink to the mobile station, is disclosed. The reception device includes a presumed probability control unit that sets a presumed probability for use in an antenna verification process of estimating a phase of the transmission signals from the plurality of antennas according to information about a channel of signals transmitted in an uplink from the mobile station to the radio base station when a closed loop transmission diversity control is performed by controlling the phase of the transmission signals from the plurality of antennas according to feedback information noticed by the mobile station to transmit the transmission signals.

Reception device, communication control method in mobile communication system

A radio network controller includes a block error detection unit configured to receive a data block from the base station and to detect a block error, and a target SIR calculation unit configured to calculate a target SIR based on the detected block error rate. The target calculation unit sets a first time section, which indicates a time section from a detection of the block error to the notification of the target SIR is to the base station when the block error is detected, shorter than a second time section, which indicates a time section from the detection of the block error to the notification of the target SIR to the base station when the block error is not detected.

Radio network controller and transmission power control method

A channel estimation value of data symbols of a data channel is calculated by weighting and averaging pilot symbols in a parallel time multiplexing method. Also, a channel estimation value of data symbols during each data symbol interval is calculated by dividing data symbols in a slot into a plurality of data symbol intervals, selecting pilot symbols suitable for calculation of a channel estimation value of data symbols during each data symbol interval and weighting and averaging that pilot symbols. Also, a fading frequency is detected based on an inner product value of pilot symbols. Weighting factors are changed based on the detected fading frequency. Also, a channel estimation value is calculated by weighting and averaging pilot signals using a plurality of weighting sequences. The calculated channel estimation value is used to demodulate received data.

When a closed loop transmission diversity control is performed by controlling the phase of the transmission signals from the plurality of antennas according to feedback information noticed by the mobile station to transmit the signals, an antenna verification on-off control unitcontrols the on-off of an antenna verification process of estimating the phase of the transmission signals from the plurality of antennas according to the information about the channel of the signals transmitted in the uplink from the mobile station to a radio base station. Thus, depending on the channel type (for example, a packet channel, a voice channel, etc.), the on-off control is performed on the antenna verification process, thereby performing easier and more appropriate control and improving the quality of a channel.

A mobile communication system controls switching a transmission diversity system for each channel, and improves the quality of the channel. When the channel type in an uplink is a channel for transmitting voice, open loop transmission diversity is used (steps S&#x2192;S). When the channel type in an uplink is a channel for transmitting a packet, closed loop transmission diversity is used (steps S&#x2192;S). Since the open loop transmission diversity or the closed loop transmission diversity which ever is more appropriate can be used, a transmission diversity system can be appropriately switched for each channel, thereby improving the quality of the channel.

Method of controlling mobile communication system, control device, and mobile communication system

A downlink user data signal destined for a specific mobile station (-) is always transmitted from a single base station while a plurality of base stations (---, . . . ) being switched from one to another. A first downlink signal destined for the mobile station (-) is transmitted from one or a plurality of base stations through a first downlink radio channel (downlink A-DPCR). The transmission power of a second downlink radio channel (PDSCH, HS-SCCH) for transmitting a second downlink signal from the base station (-) to the mobile station (-) is provided with an offset relative to the transmission power of the first downlink radio channel from the base station (-) to the mobile station (-), thereby linking the transmission power of the second downlink radio channel with the transmission power of the first downlink radio channel. If the number of diversity branches, i.e., the number of base stations (--) simultaneously communicating with the mobile station (-) on the first downlink radio channel (downlink A-DPCH) is large, the offset for the transmission power of the second downlink radio channel (PDSCH, HS-SCCH) is increased. If the number of diversity branches is small, the offset for the transmission power of the second downlink radio channel is decreased. In this way, the offset is determined. As a result, in mobile packet communication that transmits user data for a plurality of mobile stations through a single radio channel by temporally multiplexing the data, the reception quality of the second downlink signal transmitted from the specific base station (-) on the second downlink radio channel (PDSCH, HS-SCCH) can always properly be maintained.

Transmission power control method and radio control apparatus in mobile packet communication system

An effective data multiplexing method wherein an error correction ability is exerted at the maximum so that data transmission quality is improved and a data transmitting method in which an interleaving process applicable to data transmission using interpolation pilot signal is performed are provided. The data multiplexing method includes the steps of: coding input data for each input channel; multiplexing said data which is coded; performing an interleaving process on said data which is multiplexed; and outputting said data. In the data transmitting method, when an interleaving process is performed, an interleaver is used in which the number of columns of the interleaver is twice as many as the number of slots of a frame.

Data multiplexing method and data multiplexer, and data transmitting method and data transmitter

Fading frequency decision device and method are provided. An inner product value of pilot symbols which are time multiplexed in a control channel which is parallel multiplexed with a data channel, an inner product value of pilot symbols in a channel in which data symbols and pilot symbols are time multiplexed, or an inner product value of pilot symbols of a pilot channel which is parallel multiplexed with a data channel is calculated. A fading frequency is decided based on the calculated inner product value.

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Yokohama, Japan

Hidehiro Ando