Patent ID: 7672362
Filing Date: 2010-03-02
Classification: H04W

Abstract:
1. A communications apparatus which carries out information transmission by use of a pulse train, comprising: a receiver which receives a predetermined signal; a communication environment measuring means which measures a communication environment status based on the signal received by said receiver; and a transmitter having a controller which performs transmission rate control of said pulse train and transmission energy control of each single pulse in association with each other, based on a result of measurement with said communication environment measuring unit, wherein: when a value indicating the communication environment status is favorable is measured, said controller increases the transmission rate of said pulse train and decreases transmission energy of each single pulse so as to keep an average of transmission energy equal to or less than a predetermined average value; and when a value indicating the communication environment status is unfavorable is measured, said controller decreases the transmission rate of said pulse train and increases transmission energy of each single pulse so as to keep the average of the transmission energy equal to or less than the predetermined average value, wherein said transmitter transmits said pulse train which has been controlled by said controller, wherein the control values of the pulse train transmission rate and the transmission energy of each single pulse are calculated by utilizing a result of received power measurement in compliance with equations: where P represents predetermined average transmission energy, Sr represents a result of received power of a signal which has been transmitted with the transmission energy of each single pulse St at a transmission rate Rt, Sh represents the received power ensuring a desired communications quality, St′ represents energy of a transmission pulse after the control has been applied, Rt′ represents transmission rate of a transmission pulse after the control has been applied, and K represents a constant, wherein K is equal to 1 when a received waveform for communication environment measurement and a transmission waveform for data transmission have identical propagation loss properties, wherein if there is a difference in propagation loss properties between those waveforms, then K is associated with this difference, and wherein if the propagation loss of the measurement waveform per unit distance is Lr, and the propagation loss of the transmission waveform per unit distance is Lt, then define that K=Lt/Lr.