Free channel selection method
First Claim
1. A method for selecting a free channel from a plurality of channels for radio communication, the method comprising:
- generating, for each of the plurality of channels, a first signal indicative of the strength of the signals on the respective channel;
storing, in an array of content-addressable memory cells, values representative of the first signals of each of the plurality of channels, each of the stored values being stored in a cell having an address indicative of the channel on which the first signal represented by the stored value is carried; and
selecting a stored value corresponding to a desired signal strength, wherein the address of the selected stored value is indicative of the free channel.
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Abstract
A free channel selector for selecting from a plurality of channels an optimal channel for establishing radio communication. The channels may be selected by a radio frequency (RF) module for outputting sampled signals carried on that channel. The selected signals are digitized and provided to a peak detector. The peak detector compares the strength of the signals from the various channels. A memory device, having an array of cells, is provided for storing values representative of the sampled signals of each of the plurality of channels, each of the stored values being stored in a cell having an address indicative of the channel on which the signal represented by the stored value is carried. A stored value corresponding to the lowest signal strength is selected as being the free channel. Communication will then occur over that channel.
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Citations
20 Claims
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1. A method for selecting a free channel from a plurality of channels for radio communication, the method comprising:
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generating, for each of the plurality of channels, a first signal indicative of the strength of the signals on the respective channel;
storing, in an array of content-addressable memory cells, values representative of the first signals of each of the plurality of channels, each of the stored values being stored in a cell having an address indicative of the channel on which the first signal represented by the stored value is carried; and
selecting a stored value corresponding to a desired signal strength, wherein the address of the selected stored value is indicative of the free channel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for selecting a channel for use between a cordless telephone handset and a base unit from a plurality of possible channels, comprising the steps of:
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during a time segment for one of the possible channels, measuring a value of the signal strength present on one of the channels using a peak signal detector and storing the signal strength value within a content addressable memory;
for at least one or more of the channels, repeating the steps of measuring and storing;
reading a channel number from the content addressable memory to determine which channel corresponds to a desired measured value; and
using the channel number to identify a channel for communication between the handset and the base unit. - View Dependent Claims (10, 11, 12)
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13. A method for selecting a free channel for use between a cordless telephone handset and a base unit from a plurality of possible channels, wherein the handset and base unit communicate on each of the possible channels using a communication frame consisting of a transmit window followed by a receive window, comprising the steps of:
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during a time segment for each of the possible channels, selecting one of the possible channels, setting an RF module to the selected channel, after waiting a first period of time from the setting of the RF module, measuring a value of the received signal strength for the selected channel using a peak signal detection for a second period of time, and storing the signal strength value within a content addressable memory;
while the handset and base unit are not in use and after a delay of a third period of time, continually selecting the channel corresponding to an oldest stored value and repeating the steps of setting the RF module to the selected channel, measuring the received signal strength value, and storing the signal strength value; and
when the free channel is required for using in establishing communications between the handset and the base unit, reading the channel number from the content addressable memory which possesses a minimum measured value; and
using the read channel for communication between the handset and the base unit.- View Dependent Claims (14, 15, 16)
transmitting the received signal strength from RF transmit and receive circuitry into the at peak detector;
transmitting the peak detector output to an A-to-D converter;
sampling the received signal strength using the converter; and
controlling the operation of the peak detector and the operation of the converter by a control block upon receipt of signals from a microcontroller.
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15. The method according to claim 14, wherein the desired measured value corresponds to an optimal measured value stored within the content addressable memory.
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16. The method according to claim 15, wherein the handset and base unit communicate using CT2 interface specification.
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17. An apparatus for selecting a channel for use between a cordless telephone handset and a base unit from a plurality of possible channels, comprising:
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means for measuring a value of the signal strength present on one of the channel using a peak signal detector during,la time segment for each of the possible channels;
means for storing the signal strength value within a content addressable memory during a time segment for each of the possible channels;
means for selecting another of the channels and repeating the steps of measuring and storing the signal strength value until each of the possible channels has been measured and a corresponding value stored;
means for reading the channel number from the content addressable memory which possesses a desired measured value; and
means for using the read for communication between the handset and the base unit. - View Dependent Claims (18, 19, 20)
transmitting the received signal strength from RF transmit and receive circuitry into the peak detector;
transmitting the peak detector output to an A-to-D converter;
sampling the received signal strength using the converter; and
controlling the operation of the peak detector and the operation of the converter by a control block upon receipt of signals from a microcontroller.
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20. The apparatus according to claim 19, wherein the handset and base unit communicate using CT2 interface specification.
Specification