Method and apparatus for determining with high resolution the fidelity of information received on a communications channel
First Claim
1. A method for determining a weighted average error dispersion of data signals received over a current communication channel, comprising:
- (a) detecting a frame of information on the current communications channel that includes plural redundant messages;
(b) determining a voted message from the redundant messages;
(c) splitting each redundant message and the voted message into multi-bit words and determining a weighted value for each word;
(d) summing the weighted values for each redundant message and the voted message to generate a corresponding checkword;
(e) determining a weighted average error dispersion for the received communications signal based on the sum of the differences between the voted message checkword and each redundant message checkword; and
(f) searching for another communications channel if the weighted average error dispersion is outside of a desired range.
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Accused Products
Abstract
A method and apparatus for determining with high resolution the fidelity of communications over a communications channel is disclosed. Portable/mobile radios freely roaming between multiple trunked RF communications sites calculate the fidelity of communications received over current and alternate channels with comprehensive, high bit error resolution using a weighted average error dispersion procedure. The weighted average error dispersion analysis generates for each group of redundant messages (and in some instances subpreamble bits) received by a roaming radio in each message frame a weighted average error dispersion number whose incrementally increasing magnitude reflects deteriorating signal fidelity. Decisions about switching to alternate communications channels are made by the roaming radio based on the incrementally changing weighted error dispersion number so that communication channels may be selected to achieve optimum signal fidelity and continuity of communication.
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Citations
37 Claims
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1. A method for determining a weighted average error dispersion of data signals received over a current communication channel, comprising:
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(a) detecting a frame of information on the current communications channel that includes plural redundant messages; (b) determining a voted message from the redundant messages; (c) splitting each redundant message and the voted message into multi-bit words and determining a weighted value for each word; (d) summing the weighted values for each redundant message and the voted message to generate a corresponding checkword; (e) determining a weighted average error dispersion for the received communications signal based on the sum of the differences between the voted message checkword and each redundant message checkword; and (f) searching for another communications channel if the weighted average error dispersion is outside of a desired range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. In a trunked RF communications system having plural RF repeater sites corresponding to geographical areas with each site having a corresponding RF communications channel that may be monitored by plural portable and/or mobile radio units roaming the sites area, each radio unit comprising:
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a transceiver for selectively transceiving over multiple RF communications channels, and a processor for processing redundant messages included in a message frame received on an RF communications channel corresponding to a site selected by the radio unit to determine a reference message, combining the reference message and the redundant messages to determine a weighted error dispersion, and determining a fidelity value for the selected site communications channel based on the weighted error dispersion. - View Dependent Claims (10, 11, 12, 24, 25, 26, 35)
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13. In a trunked RF communications system having plural RF repeater sites corresponding to geographical areas with each site having a corresponding RF communications channel that may be monitored by plural portable and/or mobile radio units roaming the sites areas, each radio unit comprising:
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a transceiver for selectively transceiving on multiple RF communications channels; a processor for processing messages received on an RF communications channel corresponding to a site selected by the radio unit to determine a weighted error dispersion using a reference message generated from the received messages, and determining a high resolution incremental fidelity indicator for the selected site communications channel based on the weighted error dispersion, wherein the fidelity indicator has a wide range of incremental values between desired fidelity and undesired fidelity. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 27, 28, 36)
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22. In a trunked RF communications system having plural RF repeater sites corresponding to geographical areas with each site having a corresponding RF communications channel that may be monitored by plural portable or mobile radio units roaming the site areas, each radio unit comprising:
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a transceiver for selectively transceiving over multiple RF communications channels, and electrical circuitry for processing sequential frames of message information received on an RF communications channel allocated to a site, each frame including at least a message content portion of bits and a control portion of bits, determining a reference signal for each frame from the received message information, weighting and summing bits in one of the message content and control portions to provide plural checkwords, comparing the plural checkwords with the reference signal to determine respective differences, and determining a fidelity value for a site communications channel based on the differences. - View Dependent Claims (23, 33, 34, 37)
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29. In an RF communications system having plural RF base stations corresponding to geographical areas with each base station having a corresponding RF communications channel monitored by plural portable and/or mobile radios roaming the corresponding areas, a method of operating a portable radio comprising the steps of:
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processing digital messages currently received over an RF communications channel by one of the RF base stations, generating a reference signal representative of the received digital messages, determining a fidelity value for the selected base station communications channel based on a number of differing digital bits between the reference signal and the received digital messages. - View Dependent Claims (30, 31, 32)
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Specification