BWP-Aware LO Frequency Shifting to Mitigate Noise Figure Degradation
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Solution Overview
Problem
In wireless communication systems, particularly in 5G New Radio (NR) and Long-Term Evolution (LTE), the noise figure (NF) degrades due to insufficient isolation between local oscillator (LO) frequencies for different subscribers, leading to interference and poor signal reception, especially in small form factor devices with shared power and ground nodes.
Innovation Solution
Implementing dynamic frequency shifting by applying a low intermediate frequency (LIF) offset to separate LO frequencies for different subscribers, adjusting the LO frequencies based on the frequency separation threshold to mitigate NF degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dynamic frequency shifting with LIF offset is applied to separate LO frequencies for different subscribers, then noise figure performance is improved and interference is reduced, but device complexity increases due to additional frequency tuning mechanisms
Solution Approach 1:
The patent implements dynamic frequency shifting by applying LIF offset to separate LO frequencies for different subscribers based on their operational state. The system dynamically adjusts frequency separation thresholds and applies frequency tuning mechanisms only when interference is detected, rather than using a fixed complex structure. This dynamic approach resolves the contradiction by making the complexity adaptive rather than static.
Solution Approach 2:
The patent changes the LO frequency parameter dynamically by introducing LIF offset values that can be adjusted based on frequency separation thresholds. The system modifies frequency parameters (LO frequencies, frequency offsets) to resolve interference between subscribers, thereby improving noise figure performance without requiring permanent complex hardware structures for all possible scenarios.
2Object-affected harmful factors
If frequency separation threshold is increased to improve isolation between LO frequencies, then interference is reduced, but the ability to serve multiple subscribers with close frequencies is limited
Solution Approach 1:
The system dynamically adjusts frequency separation thresholds based on the operational state of subscribers. When subscribers are in different states (e.g., one in idle state, another in active state), the system applies appropriate LIF offsets to achieve sufficient frequency separation. This dynamic threshold adjustment allows the system to maintain high isolation when needed while adapting to serve multiple subscribers with close frequencies when conditions permit.
Solution Approach 2:
The patent segments the frequency management into different modes based on subscriber states. The system identifies different operational scenarios (first subscriber in idle state, second subscriber in active state, and vice versa) and applies different frequency separation strategies to each segment. This segmentation allows optimized interference management for each subscriber pair without requiring a single fixed threshold for all scenarios.
Data Source
AI summary
Certain aspects of the present disclosure are directed towards methods and apparatus for wireless communication. An example method generally includes: comparing a page local oscillator (LO) frequency for page reception using a first subscriber and data traffic LO frequencies of respective bandwidth parts (BWPs) for data traffic reception using a second subscriber; determining a frequency offset to be applied to the page LO frequency or one or more of the data traffic LO frequencies based on the comparison of the page LO frequency and the data traffic LO frequencies; and performing frequency tuning of the page LO frequency or the one or more of the data traffic LO frequencies based on the frequency offset.