Femtocell Frequency Offset Detection and Correction
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Solution Overview
Problem
Femtocell frequency accuracy is affected by network environment conditions, leading to inaccurate frequency adjustments due to unreliable network time protocol (NTP) synchronization information.
Innovation Solution
The femtocell calculates and adjusts frequency by detecting frequency offsets, counting occurrences of exceeding default values, and recalculating using last calculated offsets or averages of network time delays and time differences, ensuring accurate frequency correction through iterative packet transmission and synchronization with an NTP server.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the femtocell uses NTP server for frequency adjustment, then frequency adjustment capability is provided, but frequency accuracy deteriorates due to network environment affecting synchronization information
Solution Approach 1:
The patent introduces an intermediary mechanism that processes NTP synchronization information before using it for frequency adjustment. The femtocell counts the number of times frequency offset exceeds a threshold and only adjusts frequency when this count is below a threshold, effectively filtering out unreliable NTP data caused by network environment issues.
Solution Approach 2:
The patent implements a feedback mechanism where the femtocell continuously monitors frequency offset against a threshold, counts exceedance events, and uses this feedback to决定是否 perform frequency adjustment. This feedback loop ensures that frequency adjustment is only performed when synchronization information is reliable.
2Productivity
If the femtocell continuously adjusts frequency based on NTP synchronization information, then frequency adjustment frequency is increased, but frequency accuracy deteriorates due to unreliable synchronization information in poor network conditions
Solution Approach 1:
The patent makes the frequency adjustment process dynamic by introducing conditional logic that adapts to network conditions. The femtocell dynamically determines whether to adjust frequency based on the counted number of threshold exceedances, rather than continuously adjusting regardless of conditions.
Solution Approach 2:
The femtocell performs self-diagnosis by monitoring its own frequency offset against a threshold and counting exceedance events. Based on this self-monitored data, it autonomously decides whether to proceed with frequency adjustment, eliminating the need for external control.
Data Source
AI summary
A femtocell includes a frequency offset detecting module and a frequency correction module. The frequency offset detecting module calculates frequency offset and detects whether the frequency offset exceeds a default frequency offset. The frequency detecting offset module counts the time of the frequency offset exceeding the default frequency offset, and detects whether the counted number of times exceed a first default number. The frequency detecting module re-calculates frequency offset after an internal when the counted number of times does not exceed the first default number. The frequency correction module uses a last calculated frequency offsets to adjust the frequency of the femtocell, when the counted number of times exceed the first default number. A method of adjusting frequency of the femtocell is also provided.