Reference Signal Indication for 5G Random Access Beam Gain
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In high-frequency communication systems, especially in 5G new radio (NR) communication, there is a challenge to improve beam gain during the random access process to compensate for severe path loss.
Innovation Solution
A reference signal indication method where a terminal device receives multiple reference signals and sends at least one codeword on a specific time-frequency resource to indicate a selected reference signal, allowing the network device to determine the selected reference signal and adjust the beam accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beamforming technology is used to compensate for severe path loss in high frequency communication, then transmission quality is improved, but the complexity of beam alignment and selection increases
Solution Approach 1:
The network device performs beam scanning and transmits SSBs in advance before the random access process. The terminal device measures RSRP of multiple SSBs and selects a candidate SSB beforehand. This preliminary beam selection action simplifies the subsequent random access process by pre-establishing beam alignment information, reducing the complexity of real-time beam alignment.
Solution Approach 2:
The patent introduces a broadcast message as an intermediary carrier that conveys beam selection information from the network device to the terminal device. The broadcast message includes mapping relationships between SSBs and PRACH resources, serving as an intermediary mechanism that simplifies the beam alignment process by providing pre-configured information without requiring complex real-time negotiation.
2Reliability
If the terminal device performs fine selection of reference signals after entering connected mode, then beam gain is optimized, but transmission latency increases
Solution Approach 1:
The terminal device completes reference signal selection and reporting during the random access process itself, rather than after entering connected mode. The terminal measures RSRP of reference signals, selects appropriate signals, and reports selection information in the random access response. This preliminary completion of beam selection before connected mode establishes reduces the time needed for fine selection afterward, thereby reducing overall transmission latency while maintaining beam gain optimization.
3Measurement precision
If the network device sends multiple SSBs in beam scanning manner for terminal selection, then beam alignment accuracy is improved, but the time consumption for random access process increases
Solution Approach 1:
The network device transmits multiple SSBs in advance through beam scanning before the terminal device needs to perform random access. The terminal device measures and selects from these pre-transmitted SSBs. This preliminary transmission of beam information reduces the time required during the actual random access process, as the terminal doesn't need to wait for the network to scan and transmit beams in real-time during the access procedure.
Solution Approach 2:
The patent uses a broadcast message as an intermediary that carries pre-configured mapping relationships between SSBs and PRACH resources. This intermediary mechanism allows the terminal to quickly determine the appropriate random access resources without requiring real-time network response for beam alignment information, thereby reducing random access time while maintaining accurate beam alignment through the pre-established mappings.
Data Source
AI summary
A reference signal indication method includes receiving a plurality of reference signals, and sending at least one codeword on a first time-frequency resource. The at least one codeword includes a first codeword. The first codeword corresponds to a first reference signal in N reference signals of the plurality of reference signals. The first reference signal is a selected reference signal. The N reference signals are a subset of the plurality of reference signals, and N is a positive integer.