PRACH Beamforming Weights for 5G UE
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Solution Overview
Problem
Current wireless communication systems face challenges in implementing effective transmit beamforming, especially in 5G systems, due to uncertainties in downlink and uplink reciprocity, which affect beamforming accuracy and efficiency.
Innovation Solution
The implementation of transmit beamforming techniques using the physical random access channel (PRACH) in user equipment (UE) for 5G systems, where UE transmits PRACH signals with varying beamforming weights, and eNB provides feedback on suitable beam indices to optimize beamforming patterns, allowing UE to select the best beams for transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transmit beamforming is implemented using PRACH in 5G systems, then beamforming accuracy and efficiency are improved, but device complexity and implementation difficulty increase
Solution Approach 1:
The patent applies preliminary action by having the UE transmit PRACH signals with varying beamforming weights before actual data transmission. The eNB evaluates these preliminary PRACH transmissions and provides feedback on suitable beam indices, allowing the system to establish optimal beamforming patterns in advance. This preliminary beam training phase enables accurate beamforming selection without adding complexity during subsequent data transmission phases.
2Productivity
If periodic beam refinement is performed using PRACH transmissions, then beamforming efficiency is improved, but training latency and collision rates increase
Solution Approach 1:
The patent implements periodic action by performing beam refinement at scheduled intervals using PRACH transmissions. The UE periodically transmits PRACH signals with different beamforming weights, and the eNB provides feedback on suitable beams at these periodic intervals. This periodic refinement maintains beamforming efficiency while managing training latency through structured, time-scheduled operations rather than continuous or ad-hoc beam training.
Solution Approach 2:
The patent applies dynamics by adaptively adjusting beamforming weights based on feedback received from the eNB. The UE dynamically selects beamforming patterns for subsequent transmissions based on the beam indices indicated in the feedback message. This dynamic adaptation allows the system to respond to changing channel conditions while reducing collision rates through informed beam selection.
3Measurement precision
If multiple beamforming weights are tested during PRACH transmission, then beam selection accuracy is improved, but collision rates and training overhead increase
Solution Approach 1:
The patent applies partial action by having the UE test multiple beamforming weights during PRACH transmission but only requiring the eNB to identify and feedback the best beam indices rather than evaluating all possible beams exhaustively. This partial evaluation approach maintains beam selection accuracy by focusing on identifying the optimal beams without the excessive overhead of comprehensive beam testing and reporting for every possible beam combination.
Data Source
AI summary
In one example, a user equipment capable to establish a communication connection with a network entity, the user equipment comprising processing circuitry to receive, from a network entity, a primary synchronization signal (xPSS) and a beamforming reference signal (xBRS) transmitted using beamforming sweeping, identify at least one suitable transmission beamforming pattern from the network entity, transmit, to the network entity, an identifier associated with the at least one suitable beamforming pattern for a downlink signal, transmit, to the network entity, an uplink transmission of the physical random access channel (PRACH) transmitted using beamforming sweeping, receive, from the user equipment, a signal comprising an identifier associated with the at least one suitable beamforming pattern in the uplink transmission, and use the at least one suitable beamforming pattern in subsequent communication with the network equipment. Other examples are also disclosed and claimed.