Random Access Preamble Transmission with Beam Information in 5G
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Solution Overview
Problem
In future radio communication systems like 5G, the challenge is to efficiently receive and transmit preambles and messages during the random access procedure using beam forming, as existing methods do not effectively handle the increased difficulty in securing coverage at high carrier frequencies due to severe distance attenuation and reduced transmit power density.
Innovation Solution
A user terminal and radio base station system that utilizes beam forming by transmitting and receiving random access preambles with beam information, allowing for efficient random access by associating beam indices with PRACH sequences and utilizing Tx/Rx reciprocity to optimize beam formation and communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beam forming is used to improve coverage at high carrier frequencies, then radio wave propagation loss is reduced, but the complexity of the random access procedure increases due to the need to handle multiple beams and associate beam indices with PRACH sequences
Solution Approach 1:
The random access procedure is segmented into multiple independent stages: DL beam detection, beam index determination, and PRACH transmission. Each stage handles a specific aspect of beam forming, allowing the system to manage complexity by breaking down the overall process into manageable segments that can be processed independently
Solution Approach 2:
The terminal performs preliminary beam detection and determines the optimal beam index before initiating PRACH transmission. By pre-establishing the beam association and determining the correct beam index in advance, the system avoids complex real-time beam selection during the random access procedure, thereby reducing operational complexity
2Reliability
If multiple beams are used to enhance communication reliability, then the probability of successful preamble reception increases, but the time required for beam selection and association increases
Solution Approach 1:
The terminal performs beam detection and determines the optimal beam index during the DL signal reception phase, before initiating PRACH transmission. This preliminary determination of beam index eliminates the need for time-consuming beam selection during the random access procedure, reducing overall time loss while maintaining high reliability
Solution Approach 2:
The terminal autonomously performs beam detection, evaluates multiple beams, and self-determines the optimal beam index without requiring external assistance or complex coordination with the base station. This self-service approach reduces signaling overhead and minimizes the time required for beam selection while ensuring reliable preamble reception
Data Source
AI summary
To properly receive a preamble and/or a message in a random access procedure in communication using beam forming, and perform random access with efficiency, a user terminal of the present invention is a user terminal for communicating with a radio base station using a plurality of types of beam forming, and is characterized by having a receiving section that receives a DL signal transmitted from the radio base station, a transmitting section that transmits a random access preamble (PRACH), and a control section that controls to transmit the PRACH including beam information on a beam of the radio base station.