PTRS Configuration for IAB and NTN Interference Mitigation
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Solution Overview
Problem
In 5G communication systems, particularly in Integrated Access and Backhaul (IAB) and Non Terrestrial Networks (NTN), there is a need for orthogonal Phase Tracking Reference Signals (PTRS) to mitigate interference between neighboring base stations and accommodate varying radio channel conditions, while minimizing overhead, due to the unique Phase Noise models and large coverage areas of NTN.
Innovation Solution
The solution involves configuring PTRS transmissions using mutually orthogonal patterns based on a basic PTRS pattern, with unique subcarrier offsets for each base station, and employing a indexing system to reduce signaling overhead, allowing for dynamic adjustment of PTRS density and pattern in both time and frequency domains to counter phase noise effects and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PTRS density is increased to counter phase noise effects in NTN, then phase tracking accuracy is improved, but signaling overhead increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting PTRS density and pattern based on radio channel conditions, MCS levels, and bandwidth allocation. Different PTRS configurations (density, time-domain position, frequency-domain position) are selected to optimize phase tracking accuracy while adapting to varying network conditions, thereby avoiding excessive signaling overhead for fixed high-density patterns.
Solution Approach 2:
The patent implements dynamics by making PTRS configuration adaptable and variable rather than fixed. The PTRS density and pattern can be dynamically changed based on backhaul link conditions, allowing the system to use higher density only when phase noise is severe, and reduce density when conditions permit, thus balancing tracking accuracy with signaling efficiency.
2Area of stationary object
If multiple relay backhaul links are configured with fixed patterns, then network coverage is extended, but PTRS interference occurs between neighboring gNBs
Solution Approach 1:
The patent applies asymmetry by introducing different PTRS patterns (different time-domain positions, frequency-domain positions, or density configurations) for different gNBs. This asymmetric configuration ensures that even when multiple relay backhaul links operate simultaneously in extended coverage areas, their PTRS do not align in a way that causes interference, thereby maintaining network coverage while eliminating harmful interference.
Solution Approach 2:
The patent implements local quality by allowing each gNB to have customized PTRS configuration parameters tailored to its specific location, radio conditions, and interference environment. This localized optimization ensures that each cell's PTRS pattern is adapted to its local context, preventing systematic interference patterns that would occur with uniform fixed patterns across the entire network.
3Productivity
If variable PTRS density is applied to adapt to dynamic backhaul bandwidth and MCS levels, then spectral efficiency is improved, but configuration complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining a set of discrete PTRS configuration options (different density levels, time-domain patterns, frequency-domain patterns). These pre-configured options are prepared in advance and can be selected based on current network conditions, avoiding the need for complex real-time calculations and simplifying the configuration process while still enabling variable density adaptation.
Solution Approach 2:
The patent implements universality by creating a unified PTRS configuration framework that can adapt to multiple different scenarios (varying bandwidth, different MCS levels, diverse radio conditions) using a common set of configuration parameters and selection criteria. This universal approach allows the same mechanism to handle diverse requirements without requiring separate complex configuration procedures for each case.
Data Source
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AI summary
The present disclosure relates to a pre-5th-Generation (5G) or 5G communication system to be provided for supporting higher data rates Beyond 4th-Generation (4G) communication system such as Long Term Evolution (LTE). Disclosed is a method of configuring PTRS transmissions in a telecommunication network employing Integrated Access and Backhaul, the method comprising the steps of transmitting PTRS on a first subcarrier in a first cell, transmitting PTRS on a second subcarrier, different to the first subcarrier, in a second cell, neighbouring the first cell and configuring the PTRS transmission subcarrier according to a predefined base pattern and an index term, whereby the index term is communicated between the first and second cells for coordination purposes.