Random Access Preamble Repetition Across Uplink Beams
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Solution Overview
Problem
The existing wireless communication systems face challenges in supporting high data traffic, increased transmission rates, and low latency while optimizing uplink transmission and reception performance, particularly in the context of next-generation mobile communication systems.
Innovation Solution
A method and apparatus for repeatedly transmitting a random access preamble using different uplink beams across multiple PRACH occasions, with the base station and user equipment coordinating through random access responses and physical uplink shared channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If random access preamble is transmitted using single beam, then device complexity is reduced, but uplink transmission performance deteriorates
Solution Approach 1:
The random access procedure is segmented into multiple transmission attempts, each using a different uplink beam. The UE divides the beam set into multiple groups and sequentially transmits preambles using beams from each group, allowing the system to achieve better transmission performance through beam diversity while managing complexity through structured segmentation of the beam search process.
Solution Approach 2:
The patent implements periodic beam sweeping where the UE cycles through different uplink beams in a predetermined sequence. Each beam is used for a specific transmission attempt, and the pattern repeats across multiple PRACH occasions. This periodic action allows the system to systematically explore different beam directions without requiring complex real-time beam selection algorithms.
2Reliability
If repeated random access preamble transmission is performed, then access reliability is improved, but transmission latency increases
Solution Approach 1:
The patent performs preliminary beam selection and grouping before the actual random access transmission. The UE identifies a set of candidate uplink beams and organizes them into groups in advance, based on downlink beam measurements. This preliminary action allows the repeated transmissions to proceed efficiently without requiring complex real-time beam selection, thereby reducing access latency while maintaining reliability through multiple transmission attempts.
3Speed
If higher subcarrier spacing is used, then transmission rate is increased, but repeated preamble transmission support deteriorates
Solution Approach 1:
The patent adapts the beam grouping strategy and transmission parameters based on the subcarrier spacing configuration. For higher subcarrier spacing, the system adjusts the number of beams per group and the repetition pattern to match the tighter timing constraints. This parameter adaptation allows the system to maintain repeated transmission capability while operating at higher transmission rates enabled by increased subcarrier spacing.
Data Source
AI summary
A method and a device for performing a random access procedure in a wireless communication system are disclosed. The method for performing a random access procedure, according to one embodiment of the present disclosure, may comprise the steps of: repeatedly transmitting, to a base station, a random access preamble in a plurality of ROs, the plurality of ROs being related to a plurality of different SS/PBCH block indexes; receiving, from the base station, one or more RARs as a response to the random access preamble; and transmitting, to the base station, a PUSCH on the basis of the one or more RARs.