摘要:
In a MIMO system performing MIMO transmission using a plurality of antennas, BER characteristics are improved. A transmission device (1) includes a mapping unit (13) that maps a transmission signal onto the IQ plane to generate carrier-modulated carrier symbols, a frequency/transmit antenna interleaving unit (frequency/polarized wave interleaving unit 15) that interleaves the carrier symbols in the frequency domain and between transmit antennas to generate interleaved data for each transmit antenna (17), and an output processing unit (16) that constructs an OFDM frame for the interleaved data for each transmit antenna (17) and transmits an OFDM signal via the transmit antennas (17).
摘要:
Stabilized carrier recovery is acheived even at the time of a low C/N ratio by measuring the phase of a signal and controlling VCO or NCO (Numerical Controlled Oscillator) using only a period having few constellation points. At this time, false lock phenomenon is avoided as follows. That is, relatively short SYNC modulated by an already-known pattern is entered into a modulation wave, VCO or NCO oscillation frequency is swept in a wide range and sweep is stopped at a frequency in which the SYNC can be received, thereby carrying out coarse control AFC. Further, a period having long to some extent, having few constellation points is provided in the modulation wave and then, a difference between the frequency of a received modulated signal and a local oscillation signal of VCO or NCO is obtained in this period. This frequency difference is analyzed according to the phase differential function method, self-correlation function method or count method, and the VCO or NCO is controlled based on this result of analysis.
摘要:
A carrier reproducing circuit which can stably reproduce carriers even when the CN ratio is low by measuring the phase of a signal by only using such a period that the multi-valued number is few and controlling a VCO or NCO (numerically controlled oscillator). At the time of reproducing the carriers, the occurrence of a pseudo-synchronous phenomenon is avoided in such a way that rough AFC is performed by inserting SYNC which is modulated with an already known pattern and has a relatively short length into modulated waves and the oscillation frequency of the VCO or NCO is swept over a wide range, and then, the sweeping is stopped at a frequency at which the SYNC is received. In addition, the period of a few multi-valued number having a certain degree of length is provided in the modulated waves and the difference between the frequency of received modulated signals and that of the local oscillation signal of the VCO or NCO in the period is determined, and then, the frequency difference is analyzed by using the phase differential function method, autocorrelation function method, or count method, etc., and the VCO or NCO is controlled based on the results of the analysis.