RACH Bandwidth Part Switching for High-Band NR Link Reliability
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Solution Overview
Problem
Existing BWP switching during random access procedures in NR systems operating above 52.6 GHz faces challenges due to high phase noise, propagation loss, and poor link performance, leading to increased radio link failures and inefficiencies in subcarrier spacing selection.
Innovation Solution
Implementing methods and systems that allow wireless devices to switch between high and low subcarrier spacing BWPs based on predefined criteria, such as channel conditions, to optimize PRACH resource configuration and reduce radio link failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high subcarrier spacing BWP is used during random access procedure, then system capacity and data rate are improved, but radio link failure increases due to high phase noise and propagation loss
Solution Approach 1:
The patent implements dynamic BWP switching during the random access procedure based on detected channel conditions. The wireless device initially uses a first BWP with higher subcarrier spacing for capacity, then switches to a second BWP with lower subcarrier spacing when random access is detected, reducing phase noise impact and improving reliability during critical access procedures.
Solution Approach 2:
The patent changes the subcarrier spacing parameter dynamically by switching between different BWPs. The first BWP uses higher subcarrier spacing (e.g., 120 kHz or 240 kHz) for normal operation, while the second BWP uses lower subcarrier spacing (e.g., 60 kHz or 30 kHz) during random access to mitigate phase noise and propagation loss effects.
2Speed
If high subcarrier spacing BWP is used during random access procedure, then end-user data rate is improved, but link performance deteriorates due to propagation loss
Solution Approach 1:
The system dynamically adjusts the subcarrier spacing by switching BWPs based on the operational state. During random access procedures, the device switches to the second BWP with lower subcarrier spacing to improve link performance and reduce propagation loss impact, while maintaining the ability to use higher subcarrier spacing for faster data rates during normal operation.
Solution Approach 2:
The patent modifies the subcarrier spacing parameter adaptively by selecting appropriate BWPs. The first BWP is configured for high-speed data transmission with higher subcarrier spacing, while the second BWP provides more robust link performance with lower subcarrier spacing during random access, balancing speed and reliability based on operational needs.
3Reliability
If BWP switching is implemented during random access procedure, then radio link failure is reduced, but device complexity increases
Solution Approach 1:
The patent pre-configures multiple BWPs with different subcarrier spacing values before random access procedures begin. The wireless device is provided with configuration information for both the first BWP (higher subcarrier spacing) and the second BWP (lower subcarrier spacing), allowing it to switch between them based on detected random access conditions without requiring complex real-time decisions.
Solution Approach 2:
The patent implements a feedback mechanism where the wireless device detects random access procedures (through monitoring of downlink signals or uplink transmission detection) and automatically triggers BWP switching from the first to the second BWP. This feedback-driven approach simplifies the switching logic by using clear detection criteria rather than complex algorithms.
Data Source
AI summary
A method, system and apparatus are disclosed. In one or more embodiments, a wireless device is provided. The wireless device includes processing circuitry configured to select one of a first bandwidth part, BWP, and a second BWP based on at least one predefined criterion where the first BWP is associated with configured first physical random access channel, PRACH, resources and a second BWP is associated with configured second PRACH resources different from the configured first PRACH resources, and implement the selected one of the first BWP and second BWP for a random access procedure.