5G Random Access Beam Group Adjustment for Success Rate

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Solution Overview

Problem

In 5G communication systems, the random access procedure can be delayed or fail due to inappropriate beam selection for transmitting random access preambles, leading to inefficiencies in data transmission and connectivity.

Innovation Solution

A method is introduced where a terminal selects an initial beam group for transmitting random access preambles, adjusts the number of beams based on failure thresholds related to Reference Signal Received Power (RSRP) or Reference Signal Received Quality (RSRQ), and reselects a new beam group with an increased number of beams to ensure successful random access procedures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a terminal uses beamforming to transmit random access preambles in 5G systems, then the transmission distance and signal quality are improved, but the random access procedure may be delayed or fail due to inappropriate beam selection

Engineering Contradiction:

Improverandom access success rateVSAvoidrandom access procedure delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The terminal performs preliminary beam measurements and selects candidate beams before initiating the random access procedure. By pre-identifying suitable beams and their associated RSRP/RSRQ values, the terminal avoids trial-and-error beam selection during random access, thereby reducing access delay while ensuring reliability through informed beam choice.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The terminal monitors the random access procedure outcome and uses feedback from RSRP/RSRQ measurements to adjust beam selection. When random access fails or is delayed, the terminal can switch to alternative beams from the candidate set, using the measurement feedback to improve subsequent access attempts and overall success rate.

Inventive Principle:

Principle #23Feedback

2Productivity

If a terminal selects a limited number of beams for random access transmission, then the procedure is faster to execute, but the reliability of successful access decreases

Engineering Contradiction:

Improverandom access execution speedVSAvoidrandom access success rate

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The terminal performs beam measurements in advance and maintains a pre-sorted candidate beam list with associated RSRP/RSRQ values before random access is needed. This preliminary preparation enables rapid beam selection during actual access attempts while ensuring reliability through access to multiple pre-evaluated beam options.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The terminal dynamically adjusts the number of candidate beams used based on conditions such as mobility state, channel environment, and access success history. In stable conditions, fewer beams are used for faster access; in challenging conditions, more beams are considered to maintain reliability, optimizing the balance between speed and success rate.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11523427B2Random access performing method, and device supporting same

Publication Date: 2022.12.06 LG ELECTRONICS INC

AI summary

Provided is a method for performing a random access procedure by a terminal in a wireless communication system. The method comprises the steps of: selecting a first beam group including a configured number (M) of beams; transmitting a random access preamble to a base station via the first beam group; adjusting a value of M when it is determined that the random access procedure has failed; and reselecting a second beam group including the adjusted number of M beams.