Carrier Aggregation Oscillator Frequency Adjustment for Intermodulation Distortion
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Solution Overview
Problem
Inter-modulation distortion (IMD) occurs in user equipment (UE) due to hardware nonlinearity when Carrier Aggregation (CA) technology is applied, severely degrading the receiving performance, especially with high interference power.
Innovation Solution
A communications apparatus and method that includes a radio frequency (RF) signal processing device with a receiving frequency synthesizer and a low intermediate frequency (IF) RX controller, which determines and adjusts the oscillating frequency of the RF signals to avoid IMD by detecting blocker signals and adjusting the frequency to move IMD signals out of the desired channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Carrier Aggregation technology is applied to provide wider transmission bandwidths and support very high data rates, then the data transmission capability is improved, but inter-modulation distortion occurs due to hardware device nonlinearity which degrades receiving performance
Solution Approach 1:
The patent changes the operating parameters (frequency offsets) of the component carriers to avoid the inter-modulation distortion products falling within the reception bandwidth. By adjusting the frequency offsets of the aggregated carriers, the system maintains the benefits of carrier aggregation while avoiding the harmful nonlinear distortion effects in the receiver hardware.
2Area of stationary object
If multiple component carriers are aggregated to increase bandwidth, then the transmission bandwidth is improved, but the complexity of frequency management and interference avoidance increases
Solution Approach 1:
The system manages the complexity by systematically adjusting frequency offset parameters of the component carriers. Rather than complex real-time control, the solution uses predetermined frequency offset adjustments that can be implemented through standard frequency synthesis mechanisms, simplifying the overall system complexity while achieving the bandwidth expansion goal.
Data Source
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AI summary
A method for avoiding inter-modulation distortion in a communications apparatus capable of supporting carrier aggregation and communicating with a peer communications apparatus in a wireless network via at least a first CC and a second CC includes: determining a frequency adjustment value for adjusting a first oscillating frequency of a first local oscillation signal utilized for processing an RF signal of the first CC or a second oscillating frequency of a second LO signal utilized for processing an RF signal of the second CC when an RF signal or a baseband signal of the second CC is interfered with by an inter-modulation distortion signal contributed by any signal component related to the first CC; and adjusting the first oscillating frequency or the second oscillating frequency according to the frequency adjustment value.