Dynamic Sub-band Pilot Allocation for Phase Noise Mitigation
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Solution Overview
Problem
In 5G NR wireless communication systems, high carrier frequency phase noise limits maximum achievable throughput due to uncompensated common phase error and inter-carrier interference, which current phase tracking reference signals cannot fully mitigate, restricting operational modulation orders and throughput even after common phase error estimation and correction.
Innovation Solution
A method involving the use of a contiguous frequency domain pilot, specifically an enhanced phase tracking reference signal, for both common phase error and inter-carrier interference estimation and correction, enabling increased throughput by selecting optimal frequency sub-bands and modulation schemes based on channel coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phase tracking reference signals are used for common phase error estimation and correction, then common phase error is mitigated, but inter-carrier interference remains uncompensated and limits throughput
Solution Approach 1:
The patent divides the frequency domain into multiple sub-bands and allocates contiguous pilots specifically within selected sub-bands rather than uniformly across the entire bandwidth. This segmentation allows the system to focus phase noise mitigation resources on sub-bands where they are most needed, enabling ICI estimation and correction without requiring pilots across the full bandwidth.
Solution Approach 2:
The patent implements dynamic sub-band selection where different sub-bands receive contiguous pilots based on local channel conditions and phase noise characteristics. This local quality approach ensures that ICI correction is applied where it provides the most benefit, rather than uniformly across all frequency resources, thereby improving throughput without excessive overhead.
2Reliability
If contiguous frequency domain pilots are allocated across the entire bandwidth, then inter-carrier interference estimation and correction is enabled, but signaling overhead and complexity increase
Solution Approach 1:
The patent segments the frequency domain into multiple sub-bands and selectively allocates contiguous pilots only in certain sub-bands based on channel conditions and phase noise characteristics. This segmentation reduces the total number of pilots required compared to full-bandwidth allocation, thereby reducing signaling overhead and device complexity while maintaining ICI correction capability where needed.
Solution Approach 2:
The patent applies partial action by allocating contiguous pilots in only some sub-bands rather than all sub-bands. The base station dynamically determines which sub-bands require ICI correction and allocates pilots accordingly, performing the necessary correction action partially rather than excessively across the entire bandwidth, thus reducing complexity.
3Productivity
If high operational modulation orders are used to increase throughput, then data rate improves, but phase noise-related errors increase and limit maximum achievable throughput
Solution Approach 1:
The patent implements a feedback mechanism where the base station transmits contiguous pilots, the UE estimates phase noise and ICI based on these pilots, and the UE feeds back channel state information including phase noise characteristics. The base station then dynamically adjusts the allocation of contiguous pilots in subsequent transmissions based on this feedback, enabling adaptive mitigation of phase noise effects and allowing higher modulation orders to be used reliably.
Solution Approach 2:
The patent replaces traditional mechanical/physical limitations by introducing signal processing-based ICI correction mechanisms. Instead of being physically limited by phase noise effects at high modulation orders, the system uses mathematical estimation and correction algorithms based on contiguous pilots to compensate for ICI, effectively substituting physical constraints with computational compensation.
4Ease of manufacture
If distributed pilots are used for phase tracking, then implementation is simple, but they cannot perform inter-carrier interference estimation and correction
Solution Approach 1:
The patent merges the functions of phase tracking and ICI mitigation by combining distributed pilots (which provide phase tracking capability) with contiguous pilots allocated in selected sub-bands (which enable ICI estimation and correction). This merging allows the system to maintain the simplicity of distributed pilot implementation while adding the ICI mitigation capability through the integrated use of contiguous pilots in specific sub-bands.
Solution Approach 2:
The patent creates a universal pilot structure where distributed pilots continue to provide phase tracking functionality while contiguous pilots in selected sub-bands provide both phase tracking and ICI correction functionality. This multi-functionality allows the pilot system to serve multiple purposes (phase tracking, ICI estimation, channel estimation) depending on the pilot allocation and configuration, thereby maintaining simplicity while enhancing capability.
Data Source
AI summary
The apparatus may be a UE configured to transmit, to a base station, an indication of a UE capability associated with a contiguous FD pilot; receive, from the base station, an indication of an allocation of one or more frequency sub-bands for a reception of one or more contiguous FD pilots; and receive, from the base station, the one or more contiguous FD pilots via the one or more frequency sub-bands. The apparatus may be a configured to receive, from a UE, an indication of a UE capability associated with a contiguous FD pilot; select one or more frequency sub-bands for a transmission of a contiguous FD pilot; transmit, to the UE, an indication of an allocation of the one or more frequency sub-bands for the transmission of the contiguous FD pilot; and transmit, to the UE, the contiguous FD pilot via the one or more frequency sub-bands.