Patent ID: 8311500

Claim:
A wireless communication device that obtains an analog received signal by receiving a wireless signal, adjusts amplitude by a variable gain amplifier, converts the analog received signal into a digital received signal by an A/D converter and obtains user data by demodulating the digital received signal, the wireless communication device comprising: a received signal strength indication detecting section that detects a received signal strength indication that fluctuates over time, based on the analog received signal; a gain controlling section that controls a gain of the variable gain amplifier, based on the received signal strength indication that fluctuates over time, detected in the received signal strength indication detecting section; a propagation environment judging section that judges a propagation environment level of the wireless signal, based on the received signal strength indication that fluctuates over time, detected by the received signal strength indication detecting section; a time constant controlling section that controls a time constant, based on the propagation environment level judged by the propagation environment judging section such that the time constant becomes larger as the propagation environment level becomes lower, the time constant regulating a change speed of the gain at the variable gain amplifier, based on the received signal strength indication that fluctuates over time, detected by the received signal strength indication detecting section; and a threshold value setting section that sets upper and lower limit threshold values for a received signal strength indication, wherein the propagation environment judging section counts per unit hour the number of instances where the received signal strength indication detected by the received signal strength indication detecting section deviates from an intensity range sandwiched between the upper and lower limit threshold values set by the threshold value setting section, and judges a propagation environment level per the unit hour in response to the counted number.