Abstract In a radio communication system using time division multiple access system (TDMA) for access control method, modulation signal sent by a slave station is frequency-dispersed during a TDMA burst period by using a chirp signal which frequency changes continuously on time axis so that signal power density on communication link is decreased and interference signal affected by the slave station to another radio communication system is reduced. According to the present invention, modulation signal transmitted by each slave station is multiplied to a chirp signal which frequency changes continuously on time axis during a TDMA burst period so that carrier frequency which carries the modulation signal changes continuously on time axis to disperse on frequency axis to a predetermined bandwidth thereby decreasing signal power density of transmit signal from the slave station. In a master station, frequency dispersed receive signal from the slave station is multiplied to another chirp signal which has opposite characteristics to that of the slave station during TDMA burst period to obtain reproduced signal. Thus, interference signal by the slave station to another radio communication system is decreased, in a return link from the slave station to said master station.
An energy dispersal method for a TDMA carrier in a radio communication system comprising: a plurality of slave stations, and a master station which communicates with said slave stations through a Time Division Multiple Access (TDMA) control system which functions as a link control protocol, each of said slave stations multiplying a modulation signal, which is sent from said slave station by a first chirp signal, said first chirp signal changes its frequency on a time axis during a TDMA burst period, wherein said modulation signal is dispersed on a frequency axis to a predetermined bandwidth by changing a carrier frequency from said slave station to said master station during said TDMA burst period, therein reducing signal power density of a transmit signal of said slave station, said master station a) receiving a frequency dispersed signal from said slave station, b) multiplying said frequency dispersed signal by a second chirp signal, which has opposite characteristics to said first chirp signal which changes frequency continuously on said time axis and which is used in said slave station during said TDMA burst period, by using TDMA burst timing information, wherein said modulation signal is reproduced in a frequency dispersed received signal, and c) demodulating said reproduced modulation signal by using a demodulator to provide a demodulated signal.
Claim 2
Dependent Claim
215 words
An energy dispersal method for a TDMA carrier in a radio communication system comprising: a plurality of slave stations, and a master station which communicates with said slave stations through a Time Division Multiple Access (TDMA) control system which functions as a link control protocol, each of said slave stations multiplying a modulation signal, which is sent from said slave station by a first chirp signal, said first chirp signal changes its frequency on a time axis during a TDMA burst period, wherein said modulation signal is dispersed on a frequency axis to a predetermined bandwidth by changing a carrier frequency from said slave station to said master station during said TDMA burst period, therein reducing signal power density of a transmit signal of said slave station, said master station a) receiving a frequency dispersed signal from said slave station, b) multiplying said frequency dispersed signal by a second chirp signal, which has opposite characteristics to said first chirp signal which changes frequency continuously on said time axis and which is used in said slave station during said TDMA burst period, by using TDMA burst timing information, wherein said modulation signal is reproduced in a frequency dispersed received signal, and c) demodulating said reproduced modulation signal by using a demodulator to provide a demodulated signal.