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: An apparatus for synchronizing pilots contained in symbols received by a receiver in a multicarrier transmission system and a method thereof are provided. Frequency or Time-frequency correlation-based scheme, with exploitation of time-frequency correlation characteristics of the pilots, may be used for identifying the positions of the pilots in frequency or time and frequency dimensions consisting of received symbols. In one example, the apparatus includes a pilot compensator and a signal selector for determining at least one correlation set, a correlator for generating one correlation set result for each of the correlation set, and a judgment or processing unit for determining positions of the pilots in response to the correlation set result.

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 interference-rejection coding method for an optical wireless communication system and such an optical wireless communication system are provided. The coding method uses delay modulation, block code techniques and filtering to reduce the low frequency interference from light sources. A plurality of codewords from the block codes are reserved for performing digital data recovery. The invention removes the need of analog clock data recovery circuit, and does not require complex hardware for realization. Therefore, it can be applied to a wide range of applications, such as optical WLAN, data transmission of medical facilities, wireless communication in the aircraft, encrypted data transmission network, and low-priced transmission interfaces.

Abstract: An interference-rejection coding method for an optical wireless communication system and such an optical wireless communication system are provided. The coding method uses delay modulation, block code techniques and filtering to reduce the low frequency interference from light sources. A plurality of codewords from the block codes are reserved for performing digital data recovery. The invention removes the need of analog clock data recovery circuit, and does not require complex hardware for realization. Therefore, it can be applied to a wide range of applications, such as optical WLAN, data transmission of medical facilities, wireless communication in the aircraft, encrypted data transmission network, and low-priced transmission interfaces.

Abstract: A structure and method for demodulating two-level differential amplitude-shift-keying signals using simple adding operations are provided. Threshold values are dynamically adjusted according to the channel response. By comparing the threshold values and the differential amplitude values, it can be found whether the amplitude of the received signal is changed. Furthermore, it no needs to know the changed value of received signal amplitudes and the differential two-level amplitude-shift-keying signals can be demodulated by just detecting whether the amplitude of the received signal is changed. By this idea, the complexity of the receiver implementation is simplified and the demodulator can get better performance.

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 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 structure and method for demodulating two-level differential amplitude-shift-keying signals using simple adding operations are provided. Threshold values are dynamically adjusted according to the channel response. By comparing the threshold values and the differential amplitude values, it can be found whether the amplitude of the received signal is changed. Furthermore, it no needs to know the changed value of received signal amplitudes and the differential two-level amplitude-shift-keying signals can be demodulated by just detecting whether the amplitude of the received signal is changed. By this idea, the complexity of the receiver implementation is simplified and the demodulator can get better performance.

Abstract: An interference-rejection coding method for an optical wireless communication system and such an optical wireless communication system are provided. The coding method uses delay modulation, block code techniques and filtering to reduce the low frequency interference from light sources. A plurality of codewords from the block codes are reserved for performing digital data recovery. The invention removes the need of analog clock data recovery circuit, and does not require complex hardware for realization. Therefore, it can be applied to a wide range of applications, such as optical WLAN, data transmission of medical facilities, wireless communication in the aircraft, encrypted data transmission network, and low-priced transmission interfaces.

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: An apparatus for synchronizing pilots contained in symbols received by a receiver in a multicarrier transmission system and a method thereof are provided. Frequency or Time-frequency correlation-based scheme, with exploitation of time-frequency correlation characteristics of the pilots, may be used for identifying the positions of the pilots in frequency or time and frequency dimensions consisting of received symbols. In one example, the apparatus includes a pilot compensator and a signal selector for determining at least one correlation set, a correlator for generating one correlation set result for each of the correlation set, and a judgment or processing unit for determining positions of the pilots in response to the correlation set result.

Abstract: There is provided an apparatus for synchronizing pilots contained in symbols received by a receiver in a multicarrier transmission system and a method thereof. Time-frequency correlation-based scheme, with exploitation of time-frequency correlation characteristics of the pilots, is used for identifying the positions of the pilots in time and frequency dimensions consisting of received symbols. The apparatus includes a pilot compensator and a signal selector for determining at least one correlation set, a correlator for generating one correlation set result for each of the correlation set, and a judgment unit for determining positions of the pilots in response to the correlation set result.

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.