Packet detection in time/frequency hopped wireless communication systems
AssigneeRealtek Semiconductor Corp.
InventorsTurgut Aytur, Stephan ten Brink, Ravishankar H. Mahadevappa, Venkatesh Rajendran, Ran Yan
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Abstract
Systems and methods for packet detection for frequency hopping networks. Multiple receiver chains are set to different frequencies to check for packets at the different frequencies, at least until receipt of a preamble sequence in a packet is received. After detection of a packet at least some of the receiver chains are used to process received signals according to a frequency hopping pattern.
Claims16
A method for detecting packets in a radio frequency (RF) communication network using orthogonal frequency division multiplexing (OFDM) in a frequency hopping manner, comprising:
- setting a first RF receiver to receive signals in a first frequency sub-band;
- setting a second RF receiver to simultaneously receive signals in a second frequency sub-band;
- checking received signals in the first frequency sub-band to determine if a first known sequence has been received;
- checking received signals in the second frequency sub-band to determine if a second known sequence has been received;
- determining if a packet has been received based on receipt of the first known sequence or receipt of the second known sequence;
- and
- selecting signals from the first RF receiver and the second RF receiver based on a hopping pattern determined according to a time frequency code after determining that a packet has been received, the time frequency code indicating usage of the first frequency sub-band and the second frequency sub-band over time for transmission of OFDM symbols.
A method of detecting receipt of a preamble sequence in a radio frequency (RF) communication network using logical channels defined by time frequency codes, the time frequency codes indicating usage of frequency sub-bands over time for transmission of orthogonal frequency division multiplexing (OFDM) symbols, comprising:
- setting each of N RF receiver chains each simultaneously to one of N different frequency sub-bands, wherein N is greater than one;
- checking signals received by the N RF receiver chains for a preamble sequence;
- determining that a packet has been received if any of the signals received by the N RF receiver chains comprise the preamble sequence;
- and
- selecting signals from the N RF receiver chains based on a hopping pattern determined according to the time frequency code after determining that a packet has been received.
A radio frequency (RF) receiver for receiving orthogonal frequency division multiplexing (OFDM) symbols on a frequency hopping communication channel defined by a time frequency code, comprising:
- a plurality of mixers, each of the plurality of mixers coupled to an antenna receiving a radio frequency signal and each of the plurality of mixers simultaneously receiving a mixing signal of a different frequency;
- a plurality of correlation circuits, each of the correlation circuits coupled to a separate mixer and each of the correlation circuits configured to determine if a received signal comprises a known sequence, wherein each correlation circuit includes both auto-correlation circuitry and cross-correlation circuitry;
- a logic circuitry that combines the correlation results based on a frequency hopping pattern defined by a time frequency code after determination by any of the correlation circuits that the received signal comprises the known sequence;
- and
- processing circuitry coupled to the mixers, the processing circuitry including a Fast Fourier Transform (FFT) block.
Dependencies are inferred from the claim text.