摘要:
Provided is a frequency error estimating method of a communication system. The method includes receiving a frame, and calculating a frequency error from a SOF field of the received frame.
摘要:
A phase locked loop includes: a loop filter; a voltage controlled oscillating unit configured to output a frequency varying according to an output voltage of the loop filter; a frequency down-converting unit configured to down-convert an output frequency of the voltage controlled oscillating unit according to a band of the output frequency of the voltage controlled oscillating unit; and a frequency divider configured to divide a frequency down-converted by the frequency down-converting unit. The output frequency of the voltage controlled oscillating unit varies according to the output voltage of the loop filter and a control signal compensating the frequency down-converted by the frequency down-converting unit.
摘要:
Provided are a forward link rain attenuation compensating apparatus using an adaptive transmission scheme in an interactive satellite communication system and a method thereof. The apparatus separates the mobile stations into clear-sky mobile stations and mobile stations in the state of rain attenuation and makes the clear-sky mobile stations receive data having a high data transmission efficiency at a high-speed while making the rain attenuation mobile stations receive the data continuously although the data transmit rate is low by making each of the two kinds of mobile stations receive data frames of a different transmission method, and provides a method therefor. The apparatus includes: a resource manager, a transmitting data format converter, a forward modulator, a backward demodulator, a receiving data format converter.
摘要:
Provided are an apparatus and method for robust Binary Phase Shift Keying/Quadrature Phase Shift Keying (BPSK/QPSK) blind modulation classification against errors in a satellite communication system. The apparatus includes first and second likelihood value calculators for calculating a likelihood value of a received baseband signal each for of BPSK and QPSK modulation modes, respectively, a maximum setting unit for deriving a maximum value of the likelihood values or ith likelihood ratios calculated by the first and second likelihood value calculators and setting a flag for the maximum value to “1” and a flag for the remaining value to “0”, first and second flag combining units for combining the flags for the modulation modes, respectively, a modulation mode flag setting unit for selecting a maximum value from the flags combined by the first and second flag combining units, and a modulation classification mode deciding unit.
摘要:
Provided are an apparatus and method for robust Binary Phase Shift Keying/Quadrature Phase Shift Keying (BPSK/QPSK) blind modulation classification. The apparatus includes first and second likelihood value calculators for calculating a likelihood value of a received baseband signal each for of BPSK and QPSK modulation modes. A maximum setting unit derives a maximum value of the likelihood values or ith likelihood ratios calculated by the first and second likelihood value calculators. A flag is set for the maximum value to “1” and a flag for the remaining value is set to “0”. First and second flag combining units combine the flags for the modulation modes. A modulation mode flag setting unit selects a maximum value from the flags combined by the first and second flag combining units.