Patent ID: 7787898

Claim:
A mobile wireless communication terminal having a contactless communication function to perform contactless communication by using a carrier wave of a predetermined frequency, the mobile wireless communication terminal comprising: communication means for performing wireless communications with a base station by using a frequency band overlapping at least in part with a spurious radiation wave frequency range resulting from the carrier wave of said predetermined frequency; transmission power setup means for setting up signal transmission power in accordance with an instruction from said base station; reception intensity measurement means for measuring signal reception intensity in wireless communications with said base station; reception quality information generation means for generating information representing reception quality of the terminal on the basis of the signal reception intensity measured by said reception intensity measurement means; noise power estimation means for estimating noise power of said spurious radiation wave in the frequency band used for the wireless communications with said base station, on the basis of the signal transmission power set up by said transmission power setup means, the signal reception intensity measured by said reception intensity measurement means, and a coefficient inherent to the terminal; detection means for detecting at least that said contactless communication function is started; and control means for comparing a predetermined threshold value with said reception quality taking account of the estimated noise power of said spurious radiation wave when said detection means detects that said contactless communication function is started, and for controlling said communication means to lower a transmission speed for wireless communication with said base station in a case where said reception quality is equal to or less than the predetermined threshold value.