MAC-PHY Random Access Signaling for Dual Connectivity

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Solution Overview

Problem

In wireless communication systems, particularly in LTE, the conventional random access procedures for dual connectivity face challenges such as interference and inefficiency when multiple MAC entities in a user equipment (UE) attempt to perform random access procedures simultaneously, leading to unwanted delays and increased costs per bit.

Innovation Solution

A method where the first MAC entity of a UE informs the first PHY entity of a random access preamble transmission failure, allowing the MAC entity to continue or stop the random access procedure without incrementing the preamble transmission counter, and to reselect a random access resource without increasing transmission power, thereby minimizing interference and optimizing resource usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple MAC entities in a UE perform random access procedures simultaneously for dual connectivity, then service availability and connection establishment are improved, but interference between random access procedures increases and resource usage becomes inefficient

Engineering Contradiction:

Improveservice availabilityVSAvoidinterference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the random access procedure by introducing separate counters for different failure types: preamble transmission counter for physical layer failures and random access procedure counter for MAC layer failures. This segmentation allows independent tracking and management of different failure modes, enabling the system to distinguish between transient physical layer issues and genuine access failures, thereby reducing unnecessary interference while maintaining service availability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter management approach by introducing distinct counter variables (preamble transmission counter and random access procedure counter) with different increment conditions and thresholds. This parameter differentiation allows the system to adapt its behavior based on the specific failure type, optimizing resource usage by avoiding redundant access attempts while maintaining reliable connection establishment.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the preamble transmission counter is incremented on every failure, then transmission reliability is improved through retransmission, but unnecessary retransmissions increase delays and resource consumption

Engineering Contradiction:

Improvetransmission reliabilityVSAvoiddelays

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the failure counting mechanism into two distinct counters: one for physical layer preamble transmission failures and another for MAC layer random access procedure failures. This segmentation prevents the premature increment of the procedure counter due to physical layer issues, thereby avoiding unnecessary retransmissions and reducing delays while maintaining transmission reliability through appropriate retransmission at the physical layer.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary mechanism where the physical layer independently manages preamble transmission attempts and only notifies the MAC layer when the preamble transmission counter reaches its maximum. This intermediary approach filters out transient physical layer failures from triggering MAC layer retransmission procedures, thereby reducing unnecessary delays and resource consumption.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If transmission power is increased on every random access failure, then access success probability is improved, but interference to other users increases and power consumption rises

Engineering Contradiction:

Improveaccess success probabilityVSAvoidinterference to other users

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent segments the power control decision-making process by introducing a distinct counter for MAC layer random access procedure failures. This segmentation ensures that transmission power is only increased when there is a genuine MAC layer access failure, not due to transient physical layer preamble transmission issues. This selective power increase reduces interference to other users while maintaining access success probability for legitimate access attempts.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the power control parameter update logic by linking power increases specifically to MAC layer procedure failures rather than all failures. This parameter change ensures that transmission power is adjusted only when necessary, reducing unnecessary power increases that would cause interference to other users while still improving access success probability for genuine access failures.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11856613B2Communication between MAC and PHY for parallel random access procedures of dual connectivity

Publication Date: 2023.12.26 LG ELECTRONICS INC

AI summary

The present invention relates to a communication between MAC layer entity and PHY layer entity for parallel random access procedures of dual connectivity. In this scheme, a first PHY entity of a user equipment informs a failure of a random access preamble transmission to a first MAC entity of the UE. Then, the first MAC entity continues or stops a random access procedure without performing procedures for a random access failure.