Patent ID: 7792084
Filing Date: 2010-09-07
Classification: H04B,H04L

Abstract:
1. A MIMO antenna apparatus that receives a plurality of radio signals modulated and transmitted by a sender-side radio station apparatus using a MIMO (Multi-Input Multi-Output) communication method with a number of data streams and a modulation and demodulation method, the MIMO antenna apparatus comprising: a plurality of antenna elements for receiving the plurality of radio signals, respectively; a detector for detecting respective received signal levels of the plurality of radio signals; a MIMO demodulator for performing MIMO demodulation of the plurality of radio signals to generate a first demodulated signal, and for determining a signal quality of the first demodulated signal; a radio transmitter for wirelessly transmitting a control signal to the sender-side radio station apparatus, the control signal controlling the MIMO communication method used by the sender-side radio station apparatus; and a controller for controlling the sender-side radio station apparatus by making the radio transmitter transmit the control signal, and controlling the MIMO demodulator, so as to change, based on the received signal levels and the signal quality, at least one of the number of data streams and the modulation and demodulation method for the MIMO communication method used by the sender-side radio station apparatus and the MIMO demodulator, wherein in the case that the signal quality of the first demodulated signal is lower than a first threshold value, (1) when the received signal levels of all of the plurality of radio signals are equal to or larger than a second threshold value, the controller decreases the number of data streams for the MIMO communication method used by the sender-side radio station apparatus and the MIMO demodulator; and (2) when the received signal level of at least one of the plurality of radio signals is smaller than the second threshold value, the controller changes the modulation and demodulation method for the MIMO communication method used by the sender-side radio station apparatus and the MIMO demodulator to a modulation and demodulation method with a transmission rate lower than a current transmission rate.