Patent ID: 7248655
Filing Date: 2007-07-24
Classification: H04B,H04L

Abstract:
1. A digital wireless receiver comprising: receiving means for receiving a modulated signal including a carrier signal modulated with a digital encoded train, said digital encoded train comprising an error-correction encoded digital signal train; demodulating means for demodulating the received modulated signal to provide said digital encoded train; decoding means for decoding said digital encoded train to provide said digital signal train; received-signal strength detecting means for developing a received-signal strength indicative signal indicative of a received-signal strength of said modulated signal; bit error rate computing means for computing a bit error rate during said decoding; and judging means to which said received-signal strength indicative signal and said bit error rate are inputted, said judging means judging, from the inputted received-signal strength indicative signal and bit error rate, which one of a plurality of signal reception conditions a current reception condition is in; wherein said plurality of signal reception conditions comprise a receiver failure condition, an out-of-communication-area communication condition, and a disturbing signal reception condition; said conditions being defined by first, second and third received-signal strength versus bit error curves, said curves being defined in a coordinate plane in which said received-signal strength is allocated along the horizontal axis and said bit error rate is allocated along the vertical axis; said first received-signal strength versus bit error curve being such that said bit error curvilinearly decreases with increase of said received-signal strength along said first curve, said second received-signal strength versus bit error curve being obtained by shifting said first curve leftward in said coordinate plane, said third received-signal strength versus bit error curve being obtained by shifting said first curve rightward in said coordinate plane; said judging means judging said current signal reception condition to be said receiver failure condition when the combination of said received-signal strength and bit error is in a first range, which is leftward of said second curve in said coordinate plane; said judging means judging said current signal reception condition to be said out-of-communication-area communication condition when the combination of said received-signal strength and bit error is in a second range, which is leftward of a portion of a first straight line above a first intersection of said first straight line with said second curve and above a portion of said second curve leftward of said first intersection, said first straight line being in parallel with said vertical axis and passing a predetermined value of said received-signal strength; said judging means judging said current signal reception condition to be said disturbing signal reception condition when the combination of said received-signal strength and bit error is in a third range, which is rightward of a portion of said first straight line above a second intersection of said first straight line with said third curve, above a portion of a second straight line passing a predetermined value of said bit error in parallel with said horizontal axis, said portion of said second straight line being rightward of a third intersection of said second straight line with said third curve, and rightward of the portion of said third curve between said second intersection and said third intersection.