| 摘要 |
Systems and methods for using non-crystal-based reference oscillators in the transmission and reception of frequency-modulated signals are disclosed. To protect against intrusion on neighboring designated frequency bands, guard bands, having a collective width greater than the total expected error based on the contribution of the frequency error from the non-crystal-based oscillators in the transmitter and/or receiver, can be designated. To protect against inter-channel interference within a designated frequency band, transmitters and receivers can include static sub-bandwidths wider than any possible total frequency error, such that it would be impossible for a transmitter or receiver to attempt to communicate on an unintended sub-band. The determination of the total possible frequency error can be determined dynamically based on the correlation between a received training sequence and a known pattern before or a communication session to avoid or correct for frequency offset or drift due to the use of non-crystal-based reference oscillators. |
| 主权项 |
1. A method comprising:
dividing, by a receiver, a frequency band into a first plurality of sub-bands, wherein each sub-band of the first plurality of sub-bands has a corresponding central frequency that is separated from a central frequency of a neighboring sub-band of the first plurality of sub-bands by a first distance, wherein the first plurality of sub-bands comprises at least (i) a first sub-band and (ii) a second sub-band; tuning the receiver to receive signals having frequencies substantially within the first sub-band; in response to failing to receive signals having frequencies substantially within the first sub-band, tuning the receiver to receive signals having frequencies substantially within the second sub-band; in response to tuning the receiver to receive signals having frequencies substantially within the second sub-band, receiving, by the receiver, a first data packet; determining whether the first data packet includes a predetermined pattern; in response to determining that the first data packet does not include the predetermined pattern, re-dividing the frequency band into a second plurality of sub-bands, wherein each sub-band of the second plurality of sub-bands has a corresponding central frequency that is separated from a central frequency of a neighboring sub-band of the second plurality of sub-bands by a second distance, wherein the second distance is less than the first distance, wherein the second plurality of sub-bands comprises at least a third sub-band; subsequent to the re-dividing of the frequency band into the second plurality of sub-bands, tuning the receiver to receive signals having frequencies substantially within the third sub-band; in response to tuning the receiver to receive signals having frequencies substantially within the third sub-band, receiving, by the receiver, a second data packet; determining whether the second data packet includes the predetermined pattern; and in response to determining that the second data packet includes the predetermined pattern, estimating a residual frequency error, wherein the residual frequency error is associated with an error in a frequency while the receiver receives signals from a transmitter. |
