PDSCH Modulation Order Segmentation for Phase Noise Handling
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face limitations due to uncompensated blind phase noise (PN) which leads to common phase error (CPE) and inter-carrier interference (ICI), restricting maximum throughput and modulation order/code rate, especially in high signal-to-noise ratio regions.
Innovation Solution
A method involving a data-aided approach where a fraction of PDSCH symbols have restricted modulation order and code rate for blind PN estimation and correction, using an enhanced phase tracking reference signal (PT-RS) with contiguous REs, allowing for CPE and ICI mitigation with minimal overhead, enabling reliable decoding and increased throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher MCS (modulation and coding scheme) is used for PDSCH, then throughput is improved, but phase noise-induced errors increase causing decoding failures
Solution Approach 1:
The PDSCH is divided into two parts: a first part with higher MCS for high throughput and a second part with lower MCS for reliable decoding. This segmentation allows the system to simultaneously achieve high data rates while maintaining decoding reliability even in the presence of phase noise.
Solution Approach 2:
Different MCS levels are applied to different parts of the PDSCH based on their specific requirements. The first part uses higher MCS optimized for throughput, while the second part uses lower MCS optimized for reliability, allowing each portion to operate at its optimal quality level.
2Reliability
If phase noise compensation is implemented, then decoding reliability is improved, but system complexity increases
Solution Approach 1:
The system uses the second part of the PDSCH with lower MCS to estimate phase noise parameters, which then automatically compensates for phase noise in the first part with higher MCS. This self-service mechanism reduces the need for external compensation algorithms and simplifies the overall system complexity.
Solution Approach 2:
The decoding process of the second part provides feedback about phase noise conditions, which is then used to adjust and improve the decoding of the first part. This feedback loop enables adaptive phase noise compensation without requiring complex external control mechanisms.
3Measurement precision
If pilot overhead is increased for phase tracking, then phase noise estimation accuracy is improved, but resource efficiency decreases
Solution Approach 1:
The system uses the data symbols in the second part of the PDSCH to estimate phase noise, eliminating the need for additional dedicated pilot symbols. This self-service approach maintains accurate phase noise estimation while preserving resource efficiency for actual data transmission.
Data Source
AI summary
The base station may transmit to the UE, a first part and a second part of a PDSCH. The UE may decode the second part of the PDSCH. The first part of the PDSCH may be associated with a higher MCS than the second part of the PDSCH. The UE may estimate at least one of an ICI or a CPE associated with the PDSCH based on the decoding of the second part of the PDSCH. The UE may decode the first part of the PDSCH based on the decoding of the second part of the PDSCH. Decoding the first part of the PDSCH based on the decoding of the second part of the PDSCH may include correcting for the at least one of the ICI or the CPE associated with the PDSCH.