Method for preventing an unauthorized device from operating in a 800 MHz trunked radio communications system
First Claim
1. In a trunked radio communications system operating in the 800 MHz spectrum wherein the trunked radio communications system comprises at least one site, at least one control channel, at least one voice channel, and a plurality of receiving devices, a method for preventing an unauthorized device from operating in the trunked radio communications system, the method comprising the steps of:
- at a receiving device in the trunked radio communications system;
determining a transmit frequency, wherein the transmit frequency is calculated by subtracting a voice channel number from 759, multiplying by a channel spacing and adding a base frequency to yield the transmit frequency,wherein the voice channel number is communicated in an outbound signaling message defined by Motorola'"'"'s 3600-baud radio trunking protocol.
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Accused Products
Abstract
A receiving device in a trunked radio communications system determines a transmit frequency, wherein the transmit frequency is calculated by subtracting a voice channel number from 759, multiplying by a channel spacing and adding a base frequency to yield the transmit frequency. The receiving device determines a receive frequency by a base frequency+[(759−a voice channel number)*25,000 Hz], where the base frequency is at least one of 851.0125 MHz, 851.0250 MHz, and 851.000 MHz. In any case, the voice channel number is communicated in an outbound signaling message defined by Motorola'"'"'s 3600-baud radio trunking protocol.
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Citations
20 Claims
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1. In a trunked radio communications system operating in the 800 MHz spectrum wherein the trunked radio communications system comprises at least one site, at least one control channel, at least one voice channel, and a plurality of receiving devices, a method for preventing an unauthorized device from operating in the trunked radio communications system, the method comprising the steps of:
at a receiving device in the trunked radio communications system; determining a transmit frequency, wherein the transmit frequency is calculated by subtracting a voice channel number from 759, multiplying by a channel spacing and adding a base frequency to yield the transmit frequency, wherein the voice channel number is communicated in an outbound signaling message defined by Motorola'"'"'s 3600-baud radio trunking protocol. - View Dependent Claims (2, 3, 4, 5)
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6. In a trunked radio communications system operating in the 800 MHz spectrum wherein the trunked radio communications system comprises at least one site, at least one control channel, at least one voice channel, and a plurality of receiving devices, a method for preventing an unauthorized device from operating in the trunked radio communications system, the method comprising the steps of:
at a receiving device in the trunked radio communications system; requesting a voice channel for a communication; receiving an outbound signaling message on a control channel comprising a voice channel number for the receiving device to utilize for the communication on the voice channel, wherein the outbound signaling message is defined by Motorola'"'"'s 3600-baud radio trunking protocol; and tuning to about a transmit frequency, wherein the transmit frequency is determined by subtracting the voice channel number from 759, multiplying by a channel spacing and adding a base frequency to yield the transmit frequency. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. In a trunked radio communications system operating in the 800 MHz spectrum wherein the trunked radio communications system comprises at least one site, at least one control channel, at least one voice channel, and a plurality of receiving devices, a method for preventing an unauthorized device from operating in the trunked radio communications system, the method comprising the steps of:
at a receiving device in the trunked radio communications system; determining a receive frequency, wherein the receive frequency is determined by a base frequency+[(759−
a voice channel number)*25,000 Hz], wherein the base frequency is at least one of 851.0125 MHz, 851.0250 MHz, and 851.000 MHz,wherein the voice channel number is communicated in an outbound signaling message defined by Motorola'"'"'s 3600-baud radio trunking protocol. - View Dependent Claims (15, 16, 17, 18, 19, 20)
Specification