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Record W2533101121 · doi:10.1109/freq.2004.1418510

Adaptive OCXO drift correction algorithm

2005· article· en· W2533101121 on OpenAlexaff
Gareth Nicholls

Bibliographic record

Venuenot available
Typearticle
Languageen
FieldComputer Science
TopicWireless Communication Networks Research
Canadian institutionsNortel (Canada)
Fundersnot available
KeywordsKalman filterBase stationControl theory (sociology)EngineeringAlgorithmComputer scienceElectronic engineeringTelecommunications

Abstract

fetched live from OpenAlex

An algorithm has been implemented in a CDMA cellular radio system to enable a 5 fold reduction in the stability requirement of the base station time reference oscillator. The algorithm adaptively models the frequency drift characteristics of the base station time reference OCXO whilst locked to a satellite time reference signal. If the satellite time reference is lost, the OCXO model is used to provide time correction of the base station reference oscillator for a holdover period of up to 24 hours during which repair or reacquisition of the satellite time reference signal is conducted. The novel algorithm uses two parallel Kalman filters to model adaptively the temperature and aging dependent frequency stability of the OCXO. The algorithm extracts the stability dependencies of the OCXO with respect to the noisy satellite time reference. Adaptive training of the Kalman filters occurs until satellite visibility is lost, and is re-initiated after the satellite time reference has been reacquired; thus, the algorithm is cognizant of changes in the OCXO frequency stability characteristics over its lifetime. In holdover, the Kalman filters operate as predictive state machines which generate a correction signal for the base station OCXO time reference based on the trained coefficients of the adaptive models. The correction algorithm has been trialed in a CDMA base station network and demonstrated to maintain the 10 MHz timing module reference oscillator to within 1.5 /spl mu/s of the CDMA system time over a holdover period of 24 hr, well within the 3GPP2 CDMA standard cumulative time error specification of 10 /spl mu/s over an 8 hr holdover period. Simulations indicate the feasibility of the algorithm to compensate for a further 10 fold reduction in reference oscillator stability whilst still meeting the 8 hr holdover specification.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.002
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: none
GenreCandidate signal: Methods · Consensus signal: Methods
Teacher disagreement score0.010
Threshold uncertainty score0.020

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.002
Meta-epidemiology (narrow)0.0010.000
Meta-epidemiology (broad)0.0010.000
Bibliometrics0.0010.001
Science and technology studies0.0010.000
Scholarly communication0.0010.001
Open science0.0010.001
Research integrity0.0010.001
Insufficient payload (model declined to judge)0.0060.002

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.022
GPT teacher head0.277
Teacher spread0.255 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designSimulation or modeling
Domainnot available
GenreMethods

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations20
Published2005
Admission routes1
Has abstractyes

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