6 results about "Orthogonal frequency-division multiplexing" patented technology

Systems, apparatuses, and methods for processing a received OFDM signal are provided. The system comprises a tuner and a signal processing unit. The tuner is configured to receive an OFDM signal. A signal processing unit is configured to search for a possible frequency of a symbol in the received OFDM signal for a TPS lock and to decide an ambiguous frequency range according to a transmission mode of the TPS lock. The possible frequency is close or equal to a center frequency of the symbol.

The invention relates to a mapping device of a physical communication channel in an orthogonal frequency-division multiplexing system and a mapping method thereof, wherein the method implements the following steps to each flow of symbols which is generated after a code clock in a transmission block is processed, firstly orderly dividing the flow of symbols into a plurality of resource block transmission units with the resource block transmission length, secondly, determining the mapping area which integrates the resource blocks which are corresponding to the flows of symbols and the quality indicated value of the communication channels which are respectively corresponding to the resource blocks in the area, thirdly, mapping the resource transmission block unit which is near to the front most position of the unmapped position into the resource block whose indicated value of the unmapped communication channel quality is the biggest. The method improves the decrypting accuracy of a terminal and reduces the retransmitting frequency through mapping the RB transmission unit whose position is near to the front position in the flow of signals into the RB with higher CQI value.

The invention discloses a baseband receiving method and a baseband device applied to a terminal in a narrow-band wireless system, and relates to wireless communication technology. The baseband receiving method includes the steps: calculating LS (least squares) estimation values of an NRS (numeric rating scale) pilot frequency position, averaging LS results of the same subcarrier position in a subframe, and encrypting LS results of different carrier positions to obtain a list of results; calculating frequency domain correlation values, and distinguishing different gears of the correlation values. The list of encrypted LS results are filtered according to the distinguished gears, filter results serve as channel estimation values of all OFDM (orthogonal frequency division multiplexing) symbols on the subframe, noise power values are estimated according to the encrypted LS results, and finally, received signals are subjected to MIMO (multiple input multiple output) detection and demodulation according to the channel estimation values and the noise power estimation values. Compared with the prior art, the baseband receiving method has the advantages that the calculating amount of the baseband receiving process can be greatly reduced, the method is suitable for the narrow-band wireless system with low signal-to-noise ratio and low movability, and good receiving performance is achieved.

The invention provides a signal transmitting method and a signal receiving method based on TDCS (Transform Domain Communication System) differential transmission. The method comprises the following steps: acquiring a first frequency domain basic waveform vector and a second frequency domain basic waveform vector respectively by using a first frequency spectrum mask sequence as well as a first random phase complex sequence and a second random phase complex sequence which are independent of each other; performing inverse fast Fourier transform on the first frequency domain basic waveform vector and the second frequency domain basic waveform vector to obtain a first path basic modulation waveform and a second path basic modulation waveform of a time domain; extracting k bits of bit data to be transmitted, and acquiring the decimal system mapping value of the k bits of bit data to be transmitted according to a rightmost bit as highest bit principle; randomly acquiring a first decimal numeral and a second decimal numeral; acquiring a first path modulation waveform and a second path modulation waveform through shift circulation modulation; synthesizing the first path modulation waveform and the second path modulation waveform to obtain a transmission signal, and transmitting the transmission signal by using an orthogonal frequency-division multiplexing transmission module.