Nec Corporation

Tomoyuki Teramoto

Kenichiro Yagawa

Ken Kasagi

A W-CDMA base station is disclosed in which a base band processing device and a plurality of remote radio devices are provided and downward data is transmitted from the plurality of remote radio devices at the same time. The base band processing device inserts a synchronous signal into downward data, and transmits the downward data to the remote radio devices. The remote radio device extracts the synchronous signal from the downward data transmitted from the base band processing device, inserts the synchronous signal into the upward data at an insertion timing based on an extraction timing when the signal is extracted, and transmits the upward data to the base band processing device. Further, the base band processing device extracts the synchronous signal from upward data transmitted from the remote radio devices, and controls the timing for starting the dispersion process for the downward data based on a time from when the synchronous signal has been inserted into the downward data until the synchronous signal has been extracted from the upward data.

Synchronous data transmission from plural remote radio devices in W-CDMA base station

A clipping circuit to limit amplitude of an orthogonal baseband signal includes a 16-gonal clipping circuit almost equivalent to a circular clipping circuit. The 16-gonal clipping circuit includes plural stages of series-connected units each including a rectangular clipping circuit and a phase rotating module. To compensate for variation in the signal amplitude due to the rectangular clipping circuits and the phase rotating modules, an amplitude adjuster conducts amplitude scaling for the signal.

Clipping circuit and radio transmitter using the same

A cellular radio communication system, a cellular radio communication method and a rake reception method for raising the efficiency of a baseband, and increasing the freedom of the structure of the radio base station. A cellular radio communication system comprises a baseband and first to Nth transmitter-receicvers connected by a transmission line. The baseband is provided with a modulator for producing, by a digital process, modulation signals to be sent from the first to Nth transmitter-receivers, and a demodulator for demodulating digital modulation signals received and analog-to-digital converted by the first to Nth transmitter-receivers. The transmitter-receiver is provided with a digital-to-analog converter for converting a digital modulation signal to a modulation signal to be sent, and an analog-to-digital converter for converting a received modulation signal to a digital modulation signal.

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Tokyo, Japan

Tomoyuki Teramoto