US 5,668,828 A · Enhanced frequency agile radio · patentgrep

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Abstract

An enhanced frequency-agile radio for avoiding undesired signal energy, based on a prediction, by scanning an available radio spectrum, measuring a receiver output, identifying an occupied portion of the available spectrum, predicting a level of undesired signal energy in a future scan, and storing the prediction. Enhancements provided by the frequency-agile radio include lowered implementation complexity appropriate for very low cost receivers and transceivers, reduced size due to elimination of larger components allowing for physically small pocket pager applications, increased anti-jam performance appropriate for wide area networks, increased receiver sensitivity and frequency tracking desirable for voice applications, enhanced signal coding error tolerance allowing operation within congested portions of the radio band and additional signal verification means which allow correct data reception from thousands of concurrently operating, collision prone transmit-only devices such as power utility meters and long range security systems.

Claims45

Dependent claims

A method, using a frequency-agile receiver in a frequency-agile radio system, for receiving signals from a transmitter transmitting information messages on a plurality of pseudo-random frequencies, comprising the steps of:

scanning an available radio spectrum;
measuring, in a portion of the scanned available radio spectrum, at least one of receiver signal strength and quieting and signal lock quality, as a measurement;
generating, based at least in part on the measurement, a prediction of a level of interference signal energy, within the portion of the available radio spectrum, expected in a future scan of said available radio spectrum by said frequency-agile receiver;
and
storing the prediction of the level of interference signal energy in a memory location associated with the portion of the scanned available radio spectrum.

2 more elements

A method, using a frequency-agile receiver in a frequency-agile-radio system, for receiving signals from a transmitter transmitting information message on a plurality of frequencies, comprising the steps of:

scanning an available radio spectrum;
measuring, in a portion of the scanned available radio spectrum, at least one of receiver signal strength and quieting and signal lock quality, as a measurement;
generating, using the measurement, a prediction of a level of interference signal energy, within the portion of the scanned available radio spectrum, expected in a future scan of said available radio spectrum by the frequency-agile receiver;
storing the prediction of the level of interference signal energy in a memory location associated with the portion of the scanned available radio spectrum;
and
avoiding the portion of the scanned available radio spectrum in future signal receptions if the stored prediction indicates a level of interference above an interference threshold.

3 more elements

A method, using a frequency-agile receiver in a frequency-agile-radio system, for receiving signals from a transmitter transmitting information messages on a plurality of frequencies, comprising the steps of:

scanning an available radio spectrum;
measuring, in a portion of the scanned available radio spectrum, at least one of receiver signal strength and quieting and signal lock quality, as a measurement;
generating a prediction, using the measurement and information derived from previous measurements, of a level of interference signal energy, within the portion of the available radio spectrum, expected in a future scan of said frequency agile receiver;
and
storing the prediction in a memory location associated with the portion of the available radio spectrum.

2 more elements

A method, using a frequency-agile receiver in a frequency-agile radio system, for receiving signals from a transmitter transmitting information messages on a plurality of frequencies, comprising the steps of:

scanning an available radio spectrum;
measuring, in a portion of the scanned available radio spectrum, at least one of receiver signal strength and quieting and signal lock quality, as a measurement;
comparing the measurement to a threshold stored in a memory location associated with the portion of the scanned available radio spectrum;
ceasing, responsive to the measurement exceeding the threshold, to scan the available radio spectrum;
and
decoding, responsive to said ceasing step, on the portion of the scanned available radio spectrum at least one of a preamble system code that modulates a carrier frequency in said portion of the scanned available radio spectrum and identifies a transmitter as belonging to a particular system and a transmitter identifier transmitted on the carrier frequency.

3 more elements

A method, using a frequency-agile receiver in a frequency-agile-radio system, for receiving signals from a transmitter transmitting information messages on a plurality of frequencies, comprising the steps of:

(a) scanning an available radio spectrum;
(b) measuring, in a portion of the scanned available radio spectrum, at least one of receiver signal strength and quieting and signal lock quality, as a measurement;
(c) comparing the measurement to a prediction of interference on said portion of the scanned available radio spectrum stored in a memory location associated with the portion of the available radio spectrum;
(c1) performing, when said comparing step indicates the measurement exceeds at least one of the prediction and the prediction plus a trip level representing a margin of signal energy above said prediction such that a coded signal would be recognizable against an interference level equivalent to said prediction, the following steps,
(c1i) ceasing to scan the available radio spectrum, and
(c1ii) attempting to decode at least one of a preamble system code that modulates a carrier frequency in said portion of the scanned available radio spectrum and identifies a transmitter as belonging to a particular system and a transmitter identifier transmitted on the modulated carrier frequency;
(c2) continuing, responsive to the measurement not exceeding at least one of the prediction and the prediction plus a trip level, to scan the available radio spectrum and returning to step (b);
(d) identifying whether the portion of the scanned available radio spectrum measured in step (b) failed to provide a recognizable preamble system code and a transmitter identification matching an identification stored in said frequency agile receiver;
(e) generating, responsive to said portion of the scanned available radio spectrum failing to provide a recognizable preamble system code and a transmitter identification matching an identification stored in said frequency agile receiver, using at least one of the measurement, history of said portion of the scanned available radio spectrum and other information regarding said portion of the scanned available radio spectrum, a prediction of a level of interference signal energy, within the portion of the scanned available radio spectrum, expected in a future scan of said available radio spectrum by said frequency-agile receiver;
and
(f) updating, responsive to said generating step, the prediction in a memory location associated with the portion of the scanned available radio spectrum.

8 more elements

A method, using a frequency-agile receiver in a frequency-agile-radio system, for receiving signals from a transmitter transmitting information messages on a plurality of frequencies, comprising the steps of:

scanning an available radio spectrum;
measuring, in a portion of the scanned available radio spectrum, at least one of receiver signal strength and quieting and signal lock quality, as a measurement;
generating, using the measurement, a prediction of a level of interference signal energy, within the portion of the scanned available radio spectrum, expected in a future scan of said available radio spectrum by said frequency-agile receiver;
storing the prediction in a memory location associated with the portion of the scanned available radio spectrum;
avoiding, responsive to the stored prediction, future scans of said portion of the scanning available radio spectrum if the prediction indicates interference signal energy exceeding an interference signal energy threshold;
attempting to decode at least one of a preamble system code that modulates a carrier frequency within said portion of the scanned available radio spectrum and identifies a transmitter as belonging to a particular system and a transmitter identifier;
and
decoding, responsive to decoding of a preamble system code and transmitter identification, at least one of voice modulation and data transmitted on said carrier frequency.

5 more elements

A method, using a frequency-agile receiver in a frequency-agile radio system, for receiving signals from a transmitter information messages on a plurality of frequencies, comprising the steps of:

scanning an available radio spectrum;
measuring, in a portion of the scanned available radio spectrum, at least one of receiver signal strength and quieting and signal lock quality, as a measurement;
generating, using at least one of the measurement and other information regarding said portion of the scanned available radio spectrum, a prediction of a level of interference signal energy within the portion of the scanned available radio spectrum expected in a future scan of said available radio spectrum by said frequency-agile receiver, the prediction, responsive to an average level of interference signal energy remaining constant, including at least one of an average prediction and an average signal shunt level representing previous predictions of interference signal energy;
and
storing the prediction in a memory location associated with the portion of the scanned available radio spectrum.

2 more elements

A method, using a frequency-agile receiver in a frequency-agile-radio system, for receiving signals from a transmitter transmitting information messages on a plurality of frequencies, comprising the steps of:

scanning an available radio spectrum;
measuring, in a portion of the scanned available radio spectrum, at least one of receiver signal strength and quieting and signal lock quality, as a measurement;
comparing the measurement to a threshold stored in a memory location associated with the portion of the scanned available radio spectrum, the threshold including at least one of a shunt level representing an interference prediction and shunt level plus an adaptive trip level representing an amount of signal energy;
ceasing, responsive to the measurement exceeding the threshold, to scan the available radio spectrum;
and
attempting to decode at least one of a preamble system code that modulates a carrier frequency within said portion of the scanned available radio spectrum and identifies a transmitter as belonging to a particular system, a transmitter identifier, voice modulation, and data.

3 more elements

A method, using a frequency-agile receiver in a frequency-agile-radio system, for receiving signals from a transmitter transmitting information messages on a plurality of frequencies, comprising the steps of:

(a) selecting one of a bank of chirp filters to filter incoming signals and having a bandwidth matching said incoming signals while scanning an available radio spectrum;
(b) receiving a signal limited in bandwidth by the selected chirp filter on a portion of the scanned available radio spectrum;
(c) measuring at least one of signal strength and quieting and signal lock quality as a measurement of the received signal;
(c1) performing, when said measurement exceeds at least one of a shunt level representing an interference prediction and a shunt level plus a trip level representing an amount of signal energy, the following steps:
(c1i) ceasing to scan the available radio spectrum;
(c1ii) selecting at least one of an intermediate frequency (IF) filter and a baseband filter having a bandwidth similar to a bandwidth of the received signal;
and
(c1iii) attempting to decode at least one of data and voice and a preamble system code that modulates a carrier freguency within said portion of the scanned available radio spectrum and identifies a transmitter as belonging to a particular system and a transmitter identifier transmitted on said carrier frequency from the received signal passed through the selected IF or baseband filter.

5 more elements

A method, using a frequency-agile receiver in a frequency-agile-radio system, for receiving signals from a transmitter transmitting information messages on a plurality of frequencies, comprising the steps of:

(a) scanning an available radio spectrum;
(b) receiving a signal having transmitted data on said scanned available radio spectrum;
(c) selecting a filter with a bandwidth greater than that of the transmitted data and filtering the received signal with the selected filter;
(d) measuring at least one of signal strength and quieting and signal lock quality as a measurement of the received signal passed through said selected filter;
(e1) performing, when said measurement exceeds at least one of a shunt level representing an interference prediction and a shunt level plus a trip level representing an amount of signal energy, the following steps:
(e1i) ceasing to scan the available radio spectrum;
(e1ii) selecting at least one of an IF filter and a baseband filter having a bandwidth similar to a bandwidth of the transmitted data;
and
(e1iii) decoding at least one of data and voice modulation and a preamble system code that modulates a carrier frequency within said portion of the scanned available radio spectrum and identifies a transmitter as belonging to a particular system and a transmitter identifier transmitted on said carrier frequency from the received signal passed through the selected IF or baseband filter.

6 more elements

A method, using a frequency-agile receiver in a frequency-agile radio system, for receiving signals from a transmitter transmitting information messages on a plurality of frequencies, comprising the steps of:

generating a local oscillator frequency;
selecting a next frequency to be received and adjusting said oscillator frequency by processor means to output a frequency equivalent to said next frequency;
reading a shunt level representing an interference prediction associated with the next frequency from a table stored in memory means;
outputting at least one of the shunt level and a portion of the shunt level to an automatic gain control (AGC) circuit to control gain of signals received at said next frequency;
measuring at least one of receiver signal strength and quieting and signal lock quality, as a measurement;
comparing the measurement to a threshold;
and
decoding, responsive to the measurement exceeding the threshold, at least one of a preamble system code that modulates a carrier frequency within said portion of the scanned available radio spectrum and identifies a transmitter as belonging to a particular system and voice and data and a transmitter identifier.

5 more elements

A method, using a frequency-agile receiver in a frequency-agile radio system, for receiving signals from a transmitter transmitting information messages on a plurality of frequencies, comprising the steps of:

scanning an available radio spectrum;
reading a shunt level representing an interference prediction associated with a portion of the scanned available radio spectrum from a table stored in memory means;
outputting at least one of the shunt level and a portion of the shunt level to an automatic gain control (AGC) circuit to control gain of signals received at said portion of the scanned available radio spectrum;
measuring at least one of receiver signal strength and quieting and signal lock quality, of said portion of the scanned available radio spectrum, as a measurement;
comparing the measurement to at least one of a trip level representing an amount of signal energy, a shunt level less the portion of the shunt level output to the AGC circuit, and a shunt level plus a trip level less the portion of the shunt level output to the AGC circuit;
and
decoding, responsive to the measurement exceeding the at least one of a trip level, a shunt level less the portion of the shunt level output to the AGC circuit, and a shunt level plus a trip level less the portion of the shunt level output to the AGC circuit, at least one of a preamble system code that modulates a carrier frequency within said portion of the scanned available radio spectrum and identifies a transmitter as belonging to particular system and voice modulation and data and a transmitter identifier transmitted on said carrier frequency.

4 more elements

A method, using a frequency-agile receiver in a frequency-agile radio system, for receiving signals from a transmitter transmitting information messages on an imperfectly known frequency, comprising the steps of:

scanning an available radio spectrum;
reading a shunt level representing an interference prediction associated with a portion of the scanned available radio spectrum from a table stored in memory means;
outputting at least one of a shunt level and a portion of the shunt level to an automatic gain control (AGC) circuit to control gain of signals received at said portion of the scanned available radio spectrum;
measuring at least one of receiver signal strength and quieting and signal lock quality, at said portion of the scanned available radio spectrum as a measurement;
comparing the measurement to at least one of a trip level representing an amount of signal energy, a shunt level less the portion of the shunt level output to the AGC circuit, and a shunt level plus a trip level less the portion of the shunt level output to the AGC circuit;
and
decoding, responsive to the measurement exceeding the at least one of a trip level, a shunt level less the portion of the shunt level output to the AGC circuit and a shunt level plus a trip level less the portion of the shunt level output to the AGC circuit, at least one of a preamble system code that modulates a carrier frequency within said portion of the scanned available radio spectrum and identifies a transmitter as belonging to a particular system and voice modulation and data and a transmitter identifier transmitted on said carrier frequency.

4 more elements

A method, using a frequency-agile receiver in a frequency-agile radio system, for receiving signals from a transmitter transmitting information messages on a plurality of frequencies, comprising the steps of:

generating a local oscillator frequency by processor means;
selecting a-next frequency to be received and adjusting said local oscillator by processor means to output a frequency equivalent to said next frequency;
reading a shunt level representing an interference prediction associated with the next frequency from a table stored in memory means;
disabling, responsive to the shunt level exceeding a level equal to an attenuation caused by disabling a gain stage of said frequency-agile receiver plus a signal level required to establish a carrier-to-noise ratio to achieve a desired bit error rate (BER), a gain stage of said frequency-agile receiver;
measuring at least one of receiver signal strength and quieting and signal lock quality, of said next frequency, as a measurement;
comparing the measurement to at least one of a shunt level less the attenuation, and a shunt level plus a trip level representing an amount of signal energy less the attenuation;
and
decoding, responsive to the measurement exceeding at least one of a shunt level less the attenuation, and a shunt level plus a trip level less the attenuation, at least one of a preamble system code that modulates a carrier frequency within said portion of the scanned available radio spectrum and identifies a transmitter as belonging to a particular system and voice modulation and data and a transmitter identifier transmitted on said carrier frequency.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/311,774Filed 23 Sep 1994 · continuation in part
Priority: 8 May 1992
Granted: 16 Sep 1997
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

H04J 13/00
Code division multiplex systems
H03J 1/0091
Using a central processing unit, e.g. a microprocessor: provided with means for scanning over a band of frequencies
H04B 1/713
Spread spectrum techniques: using frequency hopping
H04B 1/715
Using frequency hopping: interference-related aspects

Family

Serial880,268Parent of this division · filed 8 May 1992
Serial103,993Parent of this continuation-in-part · filed 10 Aug 1993
US 5,311,541 AParent of this division · filed 10 May 1994
US 5,377,222 AParent of this continuation-in-part
US 5,668,828 AThis patent

From the US filing history. Foreign family members aren’t listed.

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