Hitachi, Ltd.

Hitachi Communication Technologies, Ltd.

Yoshiaki Hasegawa

Yoshihiro Kanomata

Tomoya Uchiike

Kazuyuki Hori

Arata Nakagoshi

Yuji Ishida

Shouhei Murakami

Masao Yamaya

Akihiro Saitou

Shinya Oota

Akihiro Saito

Kosuke Aio

It is provided a wireless communication system comprising a terminal device and a base station. The terminal device includes a plurality of wireless transmitters, an antenna coupled to each of the wireless transmitters, and a controller generating a signal to be transmitted from the antenna. The base station includes a plurality of wireless receivers, an antenna coupled to each of the wireless receivers, and a controller. The terminal device holds a predetermined upper limit of power consumption. The base station changes at least one of a MIMO multiplexing number, a modulation system, and a coding rate so that communication is performed according to a communication system that can communicate at allowable transmission power of the terminal device in case where power consumption of the terminal device exceeds the upper limit upon performing the MIMO transmission at maximum transmission power according to the wireless standard.

Wireless communication system, communication method, and base station

A receiver of a wireless base station that uses a simple mode to detect a failure is provided, and an SWswitches whether an input port of the receiveris to be connected with an antennaor to be terminated. An LNA (a low noise amplifier)amplifies an input signal with a low distortion. SWsandswitch between a first path which runs through the LNAand a second pathwhich does not run through the LNA. An AGC AMP, the gain of which is controlled such that the output thereof is constant, amplifies the signal with the controlled gain. A base station control section uses the SWto terminate the input port of the receiver so that thermal noise is input to the LNA. Further, the SWsandare changed over to determine the normality of the receiver based on the fact that a first gain of an AGC-AMPwhen connected to the first path, a second gain of the AGC-AMPwhen connected to the second path, and a difference between the first and second gains fall within their respective predetermined ranges.

Base station, receiving apparatus, and receiver trouble diagnosing method

There is a need for effectively compensating distortion when a predistortion transmitter is subject to not only a memory effect due to nonlinearity of an amplifier, but also a modulator's DC offset, IQ unbalance, or local quadrature error. A predistortor to be used is a polynomial predistortor including a polynomial basis generation portion and an inner product calculation portion. The polynomial basis generation portion delays a real part and an imaginary part of a complex input signal Sx=Ix+jQx for up to M samples to generate 2(M+1) signals, duplicately combines these signals to generate monomials having maximum degree N, and outputs, as a basis vector, all or part of the monomials depending or needs. The inner product calculation portion performs an inner product calculation using a coefficient vector, i.e., a set of complex numbers sized equally to the basis vector to find a polynomial value and outputs the value as a complex signal.

Digital predistortion transmitter

A reception sensitivity is measured at a high precision. An access terminal function portion includes the transmitter part and receiver part of a communication terminal in a radio communication system. A path switch part effects switching to connect the input ends of receivers to antennas or to terminate them. The path switch part switches the paths of a signal from a transmitter and signals toward the receivers. An access point controller adjusts a packet error rate into a predetermined range, and obtains the reception sensitivity based on the transmission power of the access terminal function portion after the adjustment.

Radio access point testing apparatus and method of testing radio access point

The normality verification and radio characteristics test of a radio communication system are executed. RF-SWs (radio-frequency coaxial switches) change-over the paths of signals which are transmitted to and received from an access terminal function portion included in an access point. RF-SWs connect the access terminal function portionwith a desired one of radio analog portions. A test function controller controls the changeover operations of the RF-SWs in accordance with information designated by a maintenance apparatus (OMC). An access point controller controls in accordance with received test sort information, one or more of (1) an antenna failure test, (2) a receiver failure test, and (3) a transmitter failure.

Radio access point testing method and testing apparatus

The normality verification and radio characteristics test of a radio communication system are executed. RF-SWs (radio-frequency coaxial switches) change-over the paths of signals which are transmitted to and received from an access terminal function portion included in an access point. RF-SWs connect the access terminal function portion 122 with a desired one of radio analog portions. A test function controller controls the changeover operations of the RF-SWs in accordance with information designated by a maintenance apparatus (OMC). An access point controller controls in accordance with received test soil information, one or more of (1) an antenna failure test in which a voltage surface wave ratio is evaluated on the basis of the transmission power of the access terminal function portion, (2) a receiver failure test in which, after a packet error rate has been adjusted, a reception sensitivity is evaluated based on the transmission power of the access terminal function portion, and (3) a transmitter failure test in which transmission power from any of the radio analog portions is evaluated based on the reception power value of the access terminal function portion.

A reception sensitivity is measured at a high precision. An access terminal function portion includes the transmitter part and receiver part of a communication terminal in a radio communication system. A path switch part effects switching so as to connect the input ends of receivers to antennas or to terminate them. The path switch part switches the paths of a signal from a transmitter and signals toward the receivers. An access point controller adjusts a packet error rate into a predetermined range, and obtains the reception sensitivity on the transmission power of the access terminal function portion after the adjustment.

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Yokohama, Japan

Yoshiaki Hasegawa