Apparatus and method for determining a symbol rate and a carrier frequency for data transmission and reception
First Claim
1. A method of determining a symbol rate and a carrier frequency for data transmission and reception, from a transmitted probe signal received via a channel, the transmitted probe signal having a sequence of a plurality of tones having predetermined frequency, amplitude and phase characteristics, the transmitted probe signal having a first power level and a second power level, the transmitted probe signal received for a minimum duration for each of the first and second power levels to form a received probe signal having a plurality of sets of received probe tones, each set of received probe tones having a plurality of probe tone frequencies, the method comprising:
- (a) measuring an average probe signal level for each probe tone frequency of the received probe signal to form a set of probe signal average power levels;
(b) measuring an average noise level for a plurality of noise frequencies to form a set of average noise levels;
(c) determining a plurality of signal to distortion ratios, each of the plurality of signal to distortion ratios corresponding to a symbol rate and carrier frequency combination from a plurality of combinations of symbol rates and carrier frequencies, to form a set of signal to distortion ratios;
(d) forming a plurality of optimization parameters, the plurality of optimization parameters including the set of signal to distortion ratios; and
(e) based upon the plurality of optimization parameters, determining a selected symbol rate and carrier frequency combination from the plurality of combinations of symbol rates and carrier frequencies.
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Accused Products
Abstract
An apparatus and method for a data communications device, such as a modem (100, 101), to determine a symbol rate and carrier frequency combination, from a received probe signal, for optimizing a bit rate for data transmission and reception. The various embodiments utilizing a processor (108) or a digital signal processor (106) receive a probe signal, which also typically contains noise and other distortions. The various method and apparatus embodiments then determine signal to distortion ratios for a plurality of symbol rate and carrier frequency combinations (820), and other optimization parameters, such as channel characteristics and attenuation distortion parameters (830). These optimization parameters are then utilized to determine an optimal symbol rate and carrier frequency (840).
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Citations
30 Claims
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1. A method of determining a symbol rate and a carrier frequency for data transmission and reception, from a transmitted probe signal received via a channel, the transmitted probe signal having a sequence of a plurality of tones having predetermined frequency, amplitude and phase characteristics, the transmitted probe signal having a first power level and a second power level, the transmitted probe signal received for a minimum duration for each of the first and second power levels to form a received probe signal having a plurality of sets of received probe tones, each set of received probe tones having a plurality of probe tone frequencies, the method comprising:
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(a) measuring an average probe signal level for each probe tone frequency of the received probe signal to form a set of probe signal average power levels; (b) measuring an average noise level for a plurality of noise frequencies to form a set of average noise levels; (c) determining a plurality of signal to distortion ratios, each of the plurality of signal to distortion ratios corresponding to a symbol rate and carrier frequency combination from a plurality of combinations of symbol rates and carrier frequencies, to form a set of signal to distortion ratios; (d) forming a plurality of optimization parameters, the plurality of optimization parameters including the set of signal to distortion ratios; and (e) based upon the plurality of optimization parameters, determining a selected symbol rate and carrier frequency combination from the plurality of combinations of symbol rates and carrier frequencies. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A modem for data transmission and reception, the modem having an initial training period for determining a transmit power level from a transmitted probe signal received via a channel, the transmitted probe signal having a sequence of a plurality of tones having predetermined frequency, amplitude and phase characteristics, the transmitted probe signal having a first power level and a second power level, the transmitted probe signal received for a minimum duration for each of the first and second power levels to form a plurality of sets of transmitted tones, the modem comprising:
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a data access arrangement coupleable to the channel to receive the transmitted probe signal, to form a received probe signal; an analog-digital converter coupled to the data access arrangement to sample and convert the received probe signal to form a plurality of sets of received probe tones; and a processor coupled to the analog-digital converter to receive the plurality of sets of received probe tones, the processor responsive to determine an average probe signal level for each tone frequency of the plurality of sets of received probe tones to form a set of probe signal average power levels, and to determine an average noise level for a plurality of noise frequencies to form a set of average noise levels;
the processor further responsive to determine a plurality of signal to distortion ratios, each of the plurality of signal to distortion ratios corresponding to a symbol rate and carrier frequency combination from a plurality of combinations of symbol rates and carrier frequencies, to form a set of signal to distortion ratios;
the processor further responsive to form a plurality of optimization parameters, the plurality of optimization parameters including the set of signal to distortion ratios; and
based upon the plurality of optimization parameters, the processor further responsive to determine a selected symbol rate and carrier frequency combination from the plurality of combinations of symbol rates and carrier frequencies. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification