Method and system for joint mode and guard interval detection
AssigneeMediatek Incorporation
InventorChe-Li Lin
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Abstract
A method and system for guard interval size and mode detection of a DVB signal. The detection system comprises guard interval detection systems (GIDS), each corresponding to a mode and performing parallel search for the guard interval size based on the OFDM symbol period of the mode. A correlation calculator of a GIDS calculates a correlation signal corresponding to each guard interval size. Characteristics such as maximum value, number of points above a threshold, and a maximum value position in a sample period for each correlation signal are determined and compared, and a valid guard interval size is selected according to the determined characteristics. A mode information combine block retrieves and analyses the detection result from the GIDS.
Claims25
A method for guard interval size and mode detection of a Digital Video Broadcasting (DVB) signal, wherein the guard interval size comprises m potential varieties and the mode comprises n potential varieties, the DVB signal comprises an OFDM symbol period relating to the mode, the method comprising:
- sampling the DVB signal to form a digital signal;
- synchronously processing search in n presuming modes, each comprising:
- generating a preliminary correlation signal from the digital signal based on a presuming OFDM symbol period relating to the presuming mode;
- generating m correlation signals corresponding to m presuming guard interval sizes by summing the preliminary correlation signal based on a function of the presuming guard interval sizes;
- determining the maximum value NM and the number of points above a threshold NP in a sample period W for each correlation signal;
- and
- generating m search results based on the maximum value NM and the threshold NP corresponding to each correlation signal;
- determining the guard interval size and mode of the DVB signal according to the search results generated in the synchronous search step;
- and
- terminating the synchronous search when the guard interval size and mode of the DVB signal are determined.
A system for detecting guard interval size and mode of a DVB signal comprising m potential guard interval size varieties and n potential mode varieties, wherein each potential mode defines an OFDM symbol period, comprising:
- an analog to digital converter (ADC), sampling the DVB signal to form a digital signal;
- n guard interval detection systems (GIDS), obtaining the digital signal from the ADC, synchronously searching the guard interval size thereof, and generating n search results corresponding to n presuming modes respectively, each comprising:
- a correlation calculator, generating a preliminary correlation signal from the digital signal based on a presuming OFDM symbol period relating to the presuming mode, and generating m correlation signals corresponding to m presuming guard interval sizes by summing the preliminary correlation signal based on a function of the presuming guard interval sizes;
- a characteristic extractor, determining the maximum value NM and the number of points above a threshold NP in a sample period W for each correlation signal;
- and
- an information combiner, determining the validity of the presuming guard interval sizes based on NM, NP, and NI of each correlation signal;
- and
- a mode information combine block, determining the guard interval size and mode of the DVB signal according to the search results generated from the n GIDS;
- wherein the n GIDS terminate synchronous search when the guard interval size and mode of the DVB signal are determined.
Dependencies are inferred from the claim text.