Abstract: A signal receiving system, a band detection method for a multi-carrier signal and a demodulating apparatus thereof. Each carrier of the multi-carrier signal has a plurality of symbols respectively corresponding to a plurality of time. The band detection method includes: defining a scan area range according to a full band range of the multi-carrier signal; obtaining a reference symbol corresponding to each of the symbols according to time and frequency offset values in the scan area range; performing an operation on each of the symbols and corresponding reference symbol to obtain calibration information of each carrier of the multi-carrier signal; tuning the full band range of the multi-carrier signal according to the calibration information thereof.

Abstract: A system for receiving a digital broadcast includes an input terminal that receives the digital broadcast containing scalable data, and a controller for controlling an operation mode of the system. In addition, the system may also include a processor that decodes the data, and a power management device that varies the amount of data to be decoded according to the operation mode.

Abstract: A system for receiving a digital broadcast includes an input terminal that receives the digital broadcast containing scalable data, and a controller for controlling an operation mode of the system. In addition, the system may also include a processor that decodes the data, and a power management device that varies the amount of data to be decoded according to the operation mode.

Abstract: A method for synchronizing and identifying the cell code (scrambling code) of a cell in an orthogonal frequency division multiplexing (OFDM) based cellular communication system is provided. In this method, desired cell is found by utilizing a frame structure of OFDM symbols and through a corresponding cell search procedure, where the frame structure has periodic signal pattern and contains the information about the cell code of the desired cell in common pilot channel (CPICH) signal. And, the cell search method utilizes the periodic property of the frame structure to detect frame timing, and the correlation property of CPICH signal to identify the cell code. The cell search method of the present invention offers the advantages of good link quality, fast acquisition, and low power consumption.

Abstract: A method for symbol timing synchronization is provided. The method comprises the following steps. First, a correlation between a sample sequence and a delayed sample sequence is calculated to generate a correlation sequence. Wherein, the delayed sample sequence is obtained from delaying the sample sequence by N sampling points, and N is the length of the useful data for a symbol in the sample sequence. Then, a moving average of the correlation sequence is calculated to generate a cross-correlation sequence, and the cross-correlation sequence is differentiated to generate a differentiated sequence. Finally, a moving average of the differentiated sequence is calculated to generate a moving-averaged sequence, and the peak position of the moving-averaged sequence is detected in order to obtain the correct symbol timing for synchronization.

Abstract: A modulation recognition method and device for digitally modulated signals with multi-level magnitudes are provided. The modulation recognition method includes selecting plural quantization sizes used to construct plural statistic histograms related to the magnitude of a sequence of data, setting up an off-line processing to extract plural useful feature patterns for each modulation type of interest, receiving a sequence of samples of a modulated object signal and constructing plural statistic histograms related to the magnitude of these samples, and adopting a hierarchical classification method for modulation recognition. It can be applied to the adaptive-modulation communication system, software defined radio, digital broadcasting systems and military communication systems. It can also be integrated with modulation recognition techniques for other types of modulated signals to function in a universal demodulator.

Abstract: An apparatus and a method for peak-to-average power ratio reduction of an OFDM signal are disclosed. The method uses the interleaved characteristics of partial transmit sequences to partition input data x[n] of length N into several disjoint subblocks in time domain, and a complete N-point signal {tilde over (x)}[n] is composed after phase optimization, where N is the length of an OFDM signal and n=0, 1, . . . , N?1. Accordingly, the apparatus comprises an N-point inverse fast Fourier transform (N-IFFT), a de-multiplexer, a combiner, a set of memory and an adder. This invention uses only one N-IFFT, whereby it can achieve significant computation reduction. This invention requires (N/2)log2 N complex multiplications and N memory units. It also preserves the inherent property as well as advantages of an OFDM system.

Abstract: A method for synchronizing and identifying the cell code (scrambling code) of a cell in an orthogonal frequency division multiplexing (OFDM) based cellular communication system is provided. In this method, desired cell is found by utilizing a frame structure of OFDM symbols and through a corresponding cell search procedure, where the frame structure has periodic signal pattern and contains the information about the cell code of the desired cell in common pilot channel (CPICH) signal. And, the cell search method utilizes the periodic property of the frame structure to detect frame timing, and the correlation property of CPICH signal to identify the cell code. The cell search method of the present invention offers the advantages of good link quality, fast acquisition, and low power consumption.

Abstract: A low-complexity and low-latency method and apparatus in multicarrier communication systems is used for protection and transmission of the side information related to peak-to-average power ratio (PAPR) reduction. The side information is encoded by an error-correction code and transmitted through a plurality of reserved sub-carriers. Modulation of the coded side information over the reserved sub-carriers is performed separately without re-performing data modulation. Therefore, the invention dramatically reduces implementation complexity. Determination of the related parameters for PAPR reduction can be based on the PAPR level of the data modulated signal with slight degradation in PAPR reduction performance or that of level of the transmitted signal with no degradation in PAPR reduction performance.

Abstract: A method and apparatus for high-order peak-to-average power ratio reduction of an OFDM signal are disclosed. The method partitions time-domain input data x[n] of length N into M disjoint subblocks in time domain, and a complete N-point transmitted signal {tilde over (x)}[n], n=0, 1, . . . , N?1, is composed after transformation, complex multiplication, and phase optimization, where M is a power of 2, M?8 and N/M>1 is an integer. Accordingly, the apparatus comprises an N-point inverse fast Fourier transform (N-IFFT), a de-multiplexer, a transformer, two sets of memories, a plurality of complex multipliers, and an adder. This invention uses only one N-IFFT, whereby it achieves significant computation reduction. As M=8, the number of complex multiplications and that of memory units required are less than or equal to (N/2)log2N+(3N/4) and 3N/2, respectively. The invention also preserves the inherent property as well as advantages of an OFDM system.

Abstract: A method for synchronizing and identifying the cell code (scrambling code) of a cell in an orthogonal frequency division multiplexing (OFDM) based cellular communication system is provided. In this method, desired cell is found by utilizing a frame structure of OFDM symbols and through a corresponding cell search procedure, where the frame structure has periodic signal pattern and contains the information about the cell code of the desired cell in common pilot channel (CPICH) signal. And, the cell search method utilizes the periodic property of the frame structure to detect frame timing, and the correlation property of CPICH signal to identify the cell code. The cell search method of the present invention offers the advantages of good link quality, fast acquisition, and low power consumption.

Abstract: A method for symbol timing synchronization is provided. The method comprises the following steps. First, a correlation between a sample sequence and a delayed sample sequence is calculated to generate a correlation sequence. Wherein, the delayed sample sequence is obtained from delaying the sample sequence by N sampling points, and N is the length of the useful data for a symbol in the sample sequence. Then, a moving average of the correlation sequence is calculated to generate a cross-correlation sequence, and the cross-correlation sequence is differentiated to generate a differentiated sequence. Finally, a moving average of the differentiated sequence is calculated to generate a moving-averaged sequence, and the peak position of the moving-averaged sequence is detected in order to obtain the correct symbol timing for synchronization.

Abstract: An apparatus and method having a de-interleaving memory and a controller is used for de-interleaving interleaved data in a coded orthogonal frequency division multiplexing receiver. The controller generates the correct access addresses of the de-interleaving memory for the data to be de-interleaved, and controls the read and write operations to the de-interleaving memory. The controller comprises an address generator having a plurality of base address generators, and a read/write control circuitry. By using the de-interleaving memory combined with memory address computation for the interleaved data, frequency de-interleaving, block de-interleaving and time de-interleaving are performed in one-stage approach in the COFDM receiver. The memory size is reduced and the circuitry complexity for performing the de-interleaving process is relatively low.

Abstract: A system for receiving a digital broadcast includes an input terminal that receives the digital broadcast containing scalable data, and a controller for controlling an operation mode of the system. In addition, the system may also include a processor that decodes the data, and a power management device that varies the amount of data to be decoded according to the operation mode.

Abstract: A modulation recognition method and device for digitally modulated signals with multi-level magnitudes are provided. The modulation recognition method includes selecting plural of quantization sizes used to construct plural of statistic histograms related to the magnitude of a sequence of data, setting up an off-line processing to extract plural of useful feature patterns for each modulation type of interest, receiving a sequence of samples of the modulated object signal and constructing plural of statistic histograms related to the magnitude of these samples, and adopting a hierarchical classification method for modulation recognition. It can be applied to the adaptive-modulation communication system, software defined radio, digital broadcasting systems and military communication systems. It can also be integrated with modulation recognition techniques for other types of modulated signals to function in a universal demodulator.

Abstract: A method and apparatus for high-order peak-to-average power ratio reduction of an OFDM signal are disclosed. The method partitions time-domain input data x[n] of length N into M disjoint subblocks in time domain, and a complete N-point transmitted signal {tilde over (x)}[n], n=0, 1, . . . , N?1, is composed after transformation, complex multiplication, and phase optimization, where M is a power of 2, M?8 and N/M>1 is an integer. Accordingly, the apparatus comprises an N-point inverse fast Fourier transform (N-IFFT), a de-multiplexer, a transformer, two sets of memories, a plurality of complex multipliers, and an adder. This invention uses only one N-IFFT, whereby it achieves significant computation reduction. As M=8, the number of complex multiplications and that of memory units required are less than or equal to (N/2)log2N+(3N/4) and 3N/2, respectively. The invention also preserves the inherent property as well as advantages of an OFDM system.

Abstract: An apparatus and a method for peak-to-average power ratio reduction of an OFDM signal are disclosed. The method uses the interleaved characteristics of partial transmit sequences to partition input data x[n] of length N into several disjoint subblocks in time domain, and a complete N-point signal {tilde over (x)}[n] is composed after phase optimization, where N is the length of an OFDM signal and n=0, 1, . . . , N?1. Accordingly, the apparatus comprises an N-point inverse fast Fourier transform (N-IFFT), a de-multiplexer, a combiner, a set of memory and an adder. This invention uses only one N-IFFT, whereby it can achieve significant computation reduction. This invention requires (N/2)log2 N complex multiplications and N memory units. It also preserves the inherent property as well as advantages of an OFDM system.

Abstract: A method for synchronizing and identifying the cell code (scrambling code) of a cell in an orthogonal frequency division multiplexing (OFDM) based cellular communication system is provided. In this method, desired cell is found by utilizing a frame structure of OFDM symbols and through a corresponding cell search procedure, where the frame structure has periodic signal pattern and contains the information about the cell code of the desired cell in common pilot channel (CPICH) signal. And, the cell search method utilizes the periodic property of the frame structure to detect frame timing, and the correlation property of CPICH signal to identify the cell code. The cell search method of the present invention offers the advantages of good link quality, fast acquisition, and low power consumption.

Abstract: An apparatus and method having a de-interleaving memory and a controller is used for de-interleaving interleaved data in a coded orthogonal frequency division multiplexing receiver. The controller generates the correct access addresses of the de-interleaving memory for the data to be de-interleaved, and controls the read and write operations to the de-interleaving memory. The controller comprises an address generator having a plurality of base address generators, and a read/write control circuitry. By using the de-interleaving memory combined with memory address computation for the interleaved data, frequency de-interleaving, block de-interleaving and time de-interleaving are performed in one-stage approach in the COFDM receiver. The memory size is reduced and the circuitry complexity for performing the de-interleaving process is relatively low.

Abstract: A low-complexity and low-latency method and apparatus in multicarrier communication systems is used for protection and transmission of the side information related to peak-to-average power ratio (PAPR) reduction. The side information is encoded by an error-correction code and transmitted through a plurality of reserved sub-carriers. Modulation of the coded side information over the reserved sub-carriers is performed separately without re-performing data modulation. Therefore, the invention dramatically reduces implementation complexity. Determination of the related parameters for PAPR reduction can be based on the PAPR level of data modulated signal with slight degradation in PAPR reduction performance or that of transmitted signal with no degradation in PAPR reduction performance.