PRACH Spatial Setting Selection for Reliable 5G Random Access
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently determining optimal spatial settings for PRACH preambles and PDSCH transmissions during random access procedures, leading to potential miscommunications due to insufficient signal-to-interference-plus-noise ratios (SINR), especially in 5G and NR networks.
Innovation Solution
A user equipment (UE) and base station (BS) are equipped with processors and transceivers to determine and apply multiple spatial settings for PRACH preambles and PDSCH transmissions, enabling improved detection and reception through cycling of spatial filters and signaling mechanisms for channel quality feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single spatial setting is used for PRACH preamble transmission, then the device complexity is reduced, but the reliability of preamble detection and message reception deteriorates due to insufficient SINR in certain spatial directions
Solution Approach 1:
The patent segments the spatial transmission process by dividing PRACH preambles into different spatial settings (first spatial setting, second spatial setting, etc.) and associating each with specific PRACH occasions. This segmentation allows the system to target different spatial directions independently, improving detection reliability without requiring the device to manage a single complex spatial configuration.
Solution Approach 2:
The patent implements dynamic spatial setting selection where the UE cycles through multiple spatial settings across different PRACH occasions rather than using a fixed single spatial setting. This dynamic approach adapts to varying channel conditions in different spatial directions, enhancing detection reliability while the network manages the complexity of tracking multiple spatial configurations.
2Reliability
If multiple spatial settings are cycled for PRACH preambles, then the probability of successful detection improves, but the time required for random access procedure increases due to multiple transmission occasions
Solution Approach 1:
The patent applies preliminary action by having the UE prepare and cycle through multiple spatial settings in advance across different PRACH occasions before the network needs to detect the preamble. This preliminary spatial diversification ensures that when the network performs detection, it can immediately utilize the pre-prepared spatial diversity without additional delay, thus improving reception reliability without proportionally increasing access time.
Solution Approach 2:
The patent implements feedback mechanisms where the network provides spatial setting associations in RAR messages, enabling the UE to understand which spatial settings were successful. This feedback allows the system to learn from previous transmissions and optimize future spatial setting selections, improving message reception reliability while minimizing unnecessary time expenditures on ineffective spatial directions.
3Measurement precision
If spatial settings are associated with specific PRACH occasions, then the measurement precision of spatial channel quality improves, but the device complexity for tracking and managing spatial settings increases
Solution Approach 1:
The patent applies local quality by associating specific spatial settings with specific PRACH occasions, creating a localized mapping between time resources and spatial configurations. This local association allows the system to precisely measure and optimize channel quality for each spatial-occasion pair without requiring the device to track and manage all possible spatial settings globally, thus improving measurement precision while controlling complexity through localized management.
Data Source
AI summary
Methods and apparatuses for determining spatial settings during a random access procedure. A method for operating a user equipment includes determining a first physical random access channel (PRACH) preamble for transmission in a first PRACH occasion (RO) using a first spatial setting and determining a second PRACH preamble for transmission in a second RO using a second spatial setting. The method further includes transmitting the first PRACH preamble in the first RO using the first spatial setting and transmitting the second PRACH preamble in the second RO using the second spatial setting. The method further includes receiving a first physical downlink control channel (PDCCH) scheduling a reception of a first physical downlink shared channel (PDSCH) using a third spatial setting associated with the first spatial setting, or a second PDCCH scheduling a reception of a second PDSCH using a fourth spatial setting associated with the second spatial setting.