Patent ID: 7961800
Filing Date: 2011-06-14
Classification: H04L

Abstract:
1. An adaptive radio/modulation apparatus which modulates a signal based on a propagation loss or reception quality when the signal transmitted in a wireless channel is received, comprising: an adaptive modulation part for selecting a modulation scheme in a predetermined period based on the propagation loss or the reception quality, and modulating the signal in the modulation scheme; a switch for selecting a radio scheme of a single-carrier scheme or an orthogonal frequency division multiplexing (OFDM) scheme based on the propagation loss or the reception quality; a serial to parallel (S/P) converter for S/P converting the modulated signal and outputting the signal when the switch selects the single-carrier scheme; a discrete Fourier transform (DFT) part for converting the signal output from the S/P converter into a frequency domain, and generating a single-carrier signal; a second S/P converter for S/P converting the modulated signal, dividing the signal into a plurality of transmission sequences of each subcarrier, and generating an OFDM signal when the switch selects the OFDM scheme; an inverse discrete Fourier transform (IDFT) part for converting the single-carrier signal or all subcarrier signals of the OFDM signal into signals of time domains; a parallel to serial (P/S) converter for rearranging the signals converted into time domains by the IDFT part in a time series; a guard interval (GI) addition part for adding a guard interval to the signals rearranged in the time series; a quadrature modulation part for performing a quadrature frequency conversion on the single-carrier signal or the OFDM signal in a baseband that are rearranged in the time series and provided with the guard interval into a carrier band signal; and a transmission amplifier for setting a back-off appropriate for a selected radio/modulation scheme based on the propagation loss or the reception quality, and amplifying the carrier band signal based on the back-off.