PRACH Timing Advance Based on UE Distance for Extended Cell Range

Solution Overview

Problem

Current wireless communication technologies face challenges in increasing cell range without increasing the number of root sequences, leading to higher computational complexity at the gNB due to the proportional relationship between cell range and the number of root sequences used for PRACH transmission.

Innovation Solution

Estimate the distance between the user equipment (UE) and the base station to determine a timing advance for PRACH transmission, compensating for the equivalent roundtrip delay, ensuring the transmission occurs within the base station's detection window, even for larger distances, and adjust the timing if necessary to improve reception.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the number of root sequences is increased to support larger cell range, then the cell range is improved, but the computational load on the base station increases

Engineering Contradiction:

Improvecell rangeVSAvoidcomputational load

Core Design Contradiction:

Length of stationary objectVSPower

Solution Approach 1:

The patent changes the timing parameter of PRACH transmission by introducing a timing advance mechanism. Instead of increasing the number of root sequences to extend cell range, the system adjusts the transmission timing of preambles based on distance estimation, allowing distant UEs to transmit earlier so their signals arrive within the detection window at the base station.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies preliminary action by having the UE estimate its distance to the base station and calculate the required timing advance before transmitting the PRACH preamble. This preliminary timing adjustment ensures that the preamble arrives at the base station within the detection window, effectively extending cell range without requiring additional root sequences.

Inventive Principle:

Principle #10Preliminary action

2Quantity of substance

If the number of root sequences is increased to accommodate more PRACH preambles, then the PRACH transmission capacity is improved, but the computational complexity of the PRACH receiver increases

Engineering Contradiction:

Improvenumber of PRACH preamblesVSAvoidPRACH receiver computational complexity

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent changes the timing parameter of PRACH transmission by introducing a timing advance mechanism. Instead of increasing the number of root sequences to extend cell range, the system adjusts the transmission timing of preambles based on distance estimation, allowing distant UEs to transmit earlier so their signals arrive within the detection window at the base station.

Inventive Principle:

Principle #35Parameter changes

3Area of stationary object

If the cell range is extended by increasing root sequences, then the coverage area is improved, but the base station processing requirements increase

Engineering Contradiction:

Improvecoverage areaVSAvoidbase station processing power

Core Design Contradiction:

Area of stationary objectVSPower

Solution Approach 1:

The patent changes the timing parameter of PRACH transmission by introducing a timing advance mechanism. Instead of increasing the number of root sequences to extend cell range, the system adjusts the transmission timing of preambles based on distance estimation, allowing distant UEs to transmit earlier so their signals arrive within the detection window at the base station.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12634997B2Distance-based physical random-access channel timing advance to facilitate cell range improvement

Publication Date: 2026.05.19 DELL PROD LP

AI summary

The technology described herein is directed towards advancing a user equipment's initial access PRACH (physical random access channel) transmission message based on the distance between the user equipment and the base station so that the message is received within the detection window time interval of the base station (e.g., gNodeB). The timing advance can be determined based on the estimated detection window time interval's midpoint to increase the probability of the transmitted PRACH message being successfully detected by the base station. In one alternative, for unsuccessful detection the timing advance data can be modified for one or more PRACH message transmission reattempts, e.g., by multiples of the detection window time interval. In another alternative, for unsuccessful detection based on the transmitted preamble identifier not equaling the base station's returned preamble identifier, the timing advance can be increased or decreased based on the transmitted preamble identifier and the returned preamble identifier.