UE Random Access Procedure Coverage Enhancement

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Solution Overview

Problem

Current wireless communication systems, particularly in 5G NR, face challenges in maintaining adequate coverage due to higher path-loss at higher frequencies, especially for voice and low-rate data services, and there is a need for enhanced Random Access (RA) procedures to improve connectivity and reduce power consumption in poor radio conditions.

Innovation Solution

The solution involves a User Equipment (UE) determining whether to use legacy or coverage-enhanced RA procedures based on measured Reference Signal Received Power (RSRP), with coverage-enhanced RA including repetitions of Msg1 and Msg3 transmissions to improve success rates and reduce failure rates, thereby enhancing uplink coverage and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If higher frequencies are used for data communication, then data throughput is improved, but path-loss increases and coverage deteriorates

Engineering Contradiction:

Improvedata throughputVSAvoidpath-loss

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system dynamically selects between legacy RA and coverage-enhanced RA procedures based on measured RSRP values. When RSRP falls below a threshold indicating poor radio conditions, the UE switches to coverage-enhanced procedure with repetitions. This dynamic adaptation allows the system to maintain high data throughput on higher frequencies when conditions permit, while automatically compensating for increased path-loss when coverage deteriorates.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the transmission parameter by introducing repetitions of Msg1 and Msg3 in the coverage-enhanced RA procedure. When radio conditions deteriorate (low RSRP), the system increases the number of transmissions rather than maintaining a single transmission attempt. This parameter change directly addresses the increased path-loss at higher frequencies by providing multiple opportunities for successful delivery.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If coverage-enhanced RA with repetitions is used, then successful access probability is improved, but power consumption increases

Engineering Contradiction:

Improvesuccessful access probabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The UE dynamically determines whether to use coverage-enhanced RA with repetitions based on measured RSRP values. When RSRP is above the threshold indicating good radio conditions, the system uses the legacy RA procedure with single transmissions, minimizing power consumption. When RSRP falls below the threshold indicating poor conditions, the system switches to coverage-enhanced procedure with repetitions to ensure successful access. This dynamic decision-making resolves the contradiction by only incurring higher power consumption when necessary for reliable access.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The UE autonomously monitors its own RSRP measurements and self-determines whether to switch between legacy and coverage-enhanced RA procedures without external control. This self-service mechanism allows the device to adapt its transmission strategy based on its current radio conditions, automatically balancing between power consumption and successful access probability without requiring network intervention for each decision.

Inventive Principle:

Principle #25Self-service

3Use of energy by moving object

If legacy RA procedure is used, then power consumption is reduced, but successful access probability deteriorates in poor radio conditions

Engineering Contradiction:

Improvepower consumptionVSAvoidsuccessful access probability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The system dynamically selects between legacy RA and coverage-enhanced RA based on real-time RSRP measurements. When radio conditions are good (high RSRP), the legacy procedure with lower power consumption is used. When conditions deteriorate (low RSRP), the system automatically switches to coverage-enhanced procedure with repetitions, ensuring successful access probability is maintained despite the increased power consumption. This dynamic adaptation resolves the contradiction by contextually selecting the appropriate procedure.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The UE continuously monitors RSRP measurements as feedback about radio conditions and uses this feedback to determine whether to use legacy or coverage-enhanced RA procedures. The feedback mechanism allows the system to respond to changing radio conditions, switching from power-efficient legacy procedure when conditions are good to reliable coverage-enhanced procedure when conditions deteriorate, thus resolving the contradiction between power consumption and successful access probability.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS11564262B2Method and apparatus for determining to use coverage enhancement in random access procedure in a wireless communication system

Publication Date: 2023.01.24 ASUSTEK COMPUTER INC

AI summary

A method and apparatus are disclosed. In an example from the perspective of a User Equipment (UE), the UE initiates a Random Access (RA) procedure. The UE selects, from multiple carriers, a carrier for the RA procedure based on a measured Reference Signal Received Power (RSRP). The UE determines, based on the measured RSRP, whether or not to use a Physical Random Access Channel (PRACH) resource, associated with Message 3 (Msg3) repetition, for Message 1 (Msg1) transmission of the RA procedure, wherein the determination is performed after the selecting the carrier.