EP0114463A2
Expired / Lapsed
EP
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Link quality analyser and method of link quality measurement
Assignee: Boeing North American Inc
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Filing: 1983-11-14
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Granted: —
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Expires: 2003-11-14
Abstract
Abstract The link quality between a calling station (200) and a called station (201) is tested by the calling station transmitting from a link quality analyzer signal generator (1) by a plurality of signal tones. The called station (201) has a link quality analyzer signal processor (5) which receives the plurality of transmitting tones and samples them. A power spectrum is obtained of the received tones. From the statistics of the power spectrum the parameters of signal-to-noise ratio, multipath delay spread, Doppler frequency spread, frequency offset statistics, frequency-amplitude correlation, average amplitude response versus frequency, signal fading statistics, harmonic and intermodulation distortions, RMS-to-mean signal ratio, noise profile, and various noise statistics are determined. The power spectrum of the plurality of tones is measured through the use of digital sampling techniques and digital fast Fourier transform techniques that are implemented through microprocessor-level technology, the signal processor including a microprocessor (57) controlling a fast Fourier transformer (47) and another microprocessor (63) controlling a microcomputer (43) which carries out analysis of the data provided by the fast Fourier transformer (47).
Inventors
- 👤 David Harold Bliss
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 20:57
CPC Classifications
H; H04; H04B; H04B17/00; H04B17/30; H04B17/309
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
119 words
A link quality analyzer for measuring the link quality between a transmitting station (200) and a receiving station (201) comprising: signal generator means (1) for continually transmitting a plurality of signal tones; receiver means (9) for receiving the plurality of transmitted tones and link noise to obtain a received signal; sampling means (45) for time domain sampling of the received signal to obtain a set of digitized samples for M samples; fast Fourier transform means (47) for transforming the blocks of M digitized samples from the time domain to the frequency domain; and means (43) for measuring the transformed signals to obtain the link quality parameters for N blocks of M samples where M and N are positive integers.
Claim 2
Dependent Claim
119 words
A link quality analyzer for measuring the link quality between a transmitting station (200) and a receiving station (201) comprising: signal generator means (1) for continually transmitting a plurality of signal tones; receiver means (9) for receiving the plurality of transmitted tones and link noise to obtain a received signal; sampling means (45) for time domain sampling of the received signal to obtain a set of digitized samples for M samples; fast Fourier transform means (47) for transforming the blocks of M digitized samples from the time domain to the frequency domain; and means (43) for measuring the transformed signals to obtain the link quality parameters for N blocks of M samples where M and N are positive integers.
Claim 3
Dependent Claim
40 words
A link quality analyzer according to claim 1, characterized by selective calling and channel evaluation means (95, 93) for selecting the preferred frequency and equipment configuration for transmitting a message between the transmitting station (200) and the receiving station (201).
Claim 4
Dependent Claim
138 words
A link quality analyzer according to claim 1 or 2, characterised in that the measuring means (43) comprises: indexing means for indexing the transformed signal components according to frequency to obtain a power spectrum of the plurality of signal tones and link noise in sets of sample time; frequency offset measuring means for measuring the frequency offset of each member of the plurality of tones from the power spectrum; accumulator means for accumulating the power spectrum of subsequent reception of the plurality of tones and link noise to obtain an accumulated spectrum; storage means for storing each power spectrum of each set of plurality of tones and link noise as well as the frequency offset; and post acquisition measuring means for measuring the link quality parameters from the accumulated spectra, each tone power spectrum and the frequency offset.
Claim 5
Dependent Claim
80 words
A link quality analyzer according to claim 3, character-. ised in that the post acquisition measuring means comprises: separator means for separating from the accumulated power spectra, the accumulator noise power in preselected subbands excluding subbands containing link quality analyzer tones to obtain a subband noise indication for each block of M samples, and; formulation means for formulating average total noise power of all the selected subbands in each block to obtain a BLKNOISE for each block of M Samples.
Claim 6
Dependent Claim
63 words
A link quality analyzer according to claim 3, characterized in that the past-acquisition measuring means further comprises: noise amplitude measuring means for measuring the amplitude values for N blocks of M samples from noise power values for the N blocks of M samples; summation means for summing the noise amplitude values over N blocks of M samples to obtain a noise summation thereby.
Claim 7
Dependent Claim
119 words
.A link quality analyzer according to claim 3 , character- isec in that the post acquisition measure means comprises: accumulator means for accumulating noise subband powers; first averaging means for averaging the noise amplitude; second averaging means for averaging noise power; third averaging means for averaging the noise subband powers to obtain a subnoise indication; square root means for taking the square root of the average noise power to attain a first signal; divider means for dividing the average noise amplitude into the first signal to obtain the RMS/means noise ratio; and profile means for obtaining a noise profile for a set of N blocks of M data samples from the subband noise indication and the average power noise
Claim 8
Dependent Claim
67 words
A link quality analyzer according to claim 3, characterised in that the post acquisition measuring means comprises: separator means for separating tone power values for each of the N blocks of M samples to obtain a tone amplitude, TONEDATA, indications; first averaging means for averaging the TONEDATA indication for N blocks of M samples; and normalizing means for normalizing the tone amplitude average of the TONEDATA indication.
Claim 9
Dependent Claim
94 words
A link quality analyzer according to claim 3, characterised- in that the post acquisition measuring means comprises: normalizing means for normalizing tone amplitude values for each of the N blocks of M samples of data; summation means for summing the normalized tone amplitude values to obtain a summed signal; square root means for obtaining the square root of the summed signal; and divider means for dividing 7.07 into the square root of the summed signals to obtain the equivalent amplitude modulation index due to fading of each tone of the plurality of transmitted tones.
Claim 10
Dependent Claim
217 words
9 . A link quality analyzer according t f , claim 3, characterised in that the post acquisition measuring means further comprises: average frequency offset measuring means for obtaining the average frequency offset for each tone, and RMS frequency offset value detector means for detecting the RMS frequency offset value for each tone; correlator means for obtaining the amplitude correlation coefficients for each of the plurality of transmitted tones from the N blocks of H samples; frequency spread detector means for detecting the frequency spreads for each of the plurality of transmitted tones from the N blocks of M samples; envelope detector means for detecting the received envelopes for each tone of the plurality of transmitted tones; multipath delay spread detector means for detecting the multipath delay spreads as indicated by the received envelopes of each tone pair contained within the plurality of transmitted tones; multipath time delay spread detector means for detecting the multipath time delay spread as indicated by the received envelopes of each of the tone triplets contained within the plurality of transmitted tones; harmonic measuring means for detecting the second and third harmonics for each member of the plurality of transmitted tone; and intermodulation distorting measuring means for measuring the intermodulation products due to pairs of members of the plurality of transmitted tones.
Claim 11
Dependent Claim
141 words
A- link quality analyzer according to claim 3, characterised in that the post acquisition measurements means further comprises: fade detector means for detecting when the amplitude of each tone drops below a pre-established threshold fading depth detector means for detecting the average depth of a fade in amplitude of each tone, fading rate detector means for detecting the average rate of fading below the pre-established threshold in amplitude of each tone; and average burst peak detector means for detecting the average peak of a burst of noise exceeding a pre-established threshold, average burst time length measuring means for measuring the average length in time between bursts of noise; average burst rate measurement means for measuring the average number of noise bursts that occur per second, and average interburst time length measurement means for measuring the average time between noise burst occurrance.
Claim 12
Independent Claim
93 words
A method of measuring the link quality between a transmitting station and a receiving station comprising: continually transmitting a plurality of signal tones; receiving the plurality of transmitted tones and link noise to obtain a received signal; time domain sampling of the received signal to obtain a set of digitized samples for M samples; transforming the blocks of M digitized samples from the time domain to the frequency domain; and measuring the transformed signals to obtain the link quality parameters for N blocks of M samples where M and N are positive integers.
Claim 13
Independent Claim
93 words
A method of measuring the link quality between a transmitting station and a receiving station comprising: continually transmitting a plurality of signal tones; receiving the plurality of transmitted tones and link noise to obtain a received signal; time domain sampling of the received signal to obtain a set of digitized samples for M samples; transforming the blocks of M digitized samples from the time domain to the frequency domain; and measuring the transformed signals to obtain the link quality parameters for N blocks of M samples where M and N are positive integers.
Claim 14
Dependent Claim
30 words
A method according to claim 11, characterised by, the steps of: selecting the preferred frequency and equipment configuration for transmitting a meassage between the transmitting station and the receiving station.
Claim 15
Dependent Claim
122 words
A method according to Claim 11 or 12, characterised in that the step measuring the transform signals comprises: indexing the transformed sicnal components acccrding to frequency to obtain a power spectrum of the plurality of signal tones and link noise in sets of sample time; measuring means for measuring the frequency offset of each member of the plurality of tones from the power spectrum; accumulating the power spectrum of subsequent reception of the plurality of tones and link noise to obtain an accumulated spectrum; storing each power spectrum of each set of plurality of tones and link noise as well as the frequency offset; and measuring the link quality parameters from the accumulated spectra, each tone power spectrum and the frequency offset.
Claim 16
Dependent Claim
72 words
A method according to claim 13,. characterised in that the step of measuring the link quality parameters comprises; separating from the accumulated power spectra, the accumulator noise power in preselected subbands excluding subbands containing LQA tones to obtain a subband noise indication for each block of M samples, and; formulating average total noise power of all the selected subbands in each block to obtain a BLKNDISE for each block of M samples.
Claim 17
Dependent Claim
48 words
A method according to claim 13, characterised by the steps of: measuring the amplitude values for N blocks of M samples from noise power values for the N blocks of M samples; summing the noise amplitude values over N blocks of M samples to obtain noise summation thereby.
Claim 18
Dependent Claim
86 words
A method according to claim 13,characterised by the steps of: accumulating noise subband powers; averaging the noise amplitude; averaging noise power; averaging the noise subband powers to obtain a subnoise indication; taking the square root of the average noise power to attain a first signal; dividing the average noise amplitude into the first signal to obtain the RMS/means noise ratio; and obtaining a noise profile for a set of N blocks of M data samples - from the subband noise indication and the average power noise.
Claim 19
Dependent Claim
59 words
- 77. A method according to claim 13,characterised by the steps of: separating tone power values for each of the N blocks of M samples to obtain a tone amplitude, TONEDATA, indication; averaging the TONEDATA indication for N blocks of M samples; and normalizing means for normalizing the tone amplitude by the tone amplitude average of the TONEDATA indication.
Claim 20
Dependent Claim
73 words
A method according to claim 13, characterised by the steps of: normalizing tone amplitude values for each of the blocks of M samples of data; summing the normalized tone amplitude values to obtain a summed signal; obtaining the square root of the summed signal; and dividing 7.07 into the square root of the summed signals to obtain the equivalent amplitude modulation index due to facing of each of the plurality of transmitted tones.
Claim 21
Dependent Claim
153 words
A method according to claim 13, characterised by the steps of: obtaining the average frequency offset for each tone, and value for each tone; obtaining the amplitude correlation coefficients for each of the plurality of transmitted tones from the K blocks of M samples; detecting the received envelopes of each tone of the plurality of transmitted tones; detecting the frequency spreads for each of the plurality of transmitted tones from the N blocks of K samples; detecting the multipath delay spreads as indicated by the received envelopes of each tone pair contained within the plurality of transmitted tones; detecting the multipath time delay spread as indicated by the received envelopes of each of the tone triplets contained within plurality of transmitted tones; detecting the second and third harmonics for each member of the plurality of transmitted tones; and measuring the intermodulation produces due to pairs of members of the plurality of trnsmitted tones.
Claim 22
Dependent Claim
96 words
A method according to claim 13, characterised by: detecting when the amplitude of each tone drops below a pre-established threshold, detecting the average depth of a fade in amplitude of each tone, and detecting the average rate of fade below the pre-established threshold in amplitude of each tone; and detecting the average peak of a burst of noise exceeding the pre- established threshold, measuring means for measuring the average length in time between bursts of noise, measuring the average number of noise bursts that occur per second, and measuring the average time between noise burst occurrence.
References Cited (Backward Citations)
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