MAC Reset Procedures for 5G Wireless Devices

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Solution Overview

Problem

In 5G wireless networks, MAC protocol resets can cause UE to continue receiving PDCCH on the wrong BWP, leading to network inability to reach the UE, and beam failure counters are not reset, resulting in spurious beam failure recovery, affecting performance.

Innovation Solution

Switching uplink and downlink BWPs to a default BWP upon MAC reset, resetting beam failure indication counters, and stopping related timers, as well as deleting beam recovery measurements and state variables.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE continues to monitor PDCCH on the active BWP after MAC reset, then the UE maintains its current BWP configuration, but the network cannot reach the UE because the BWP configuration is inconsistent between UE and network

Engineering Contradiction:
ImproveUE reachabilityVSAvoidBWP configuration consistency
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent applies preliminary action by switching the UE to the initial BWP before normal communication resumes after MAC reset. This preemptive switch ensures that the UE and network are both on the same known BWP (initial BWP) before any data transmission occurs, preventing the configuration inconsistency problem from occurring in the first place

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the beam failure counter is not reset after MAC reset, then the counter retains historical beam failure data, but this causes spurious beam failure recovery procedures to be triggered

Engineering Contradiction:
Improvebeam failure detection accuracyVSAvoidspurious beam failure recovery
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies discarding and recovering by resetting the beam failure counter to zero after MAC reset. This discards the outdated beam failure history that is no longer relevant to the current MAC configuration, preventing spurious beam failure recovery procedures while preserving the ability to detect actual beam failures in the new configuration

Inventive Principle:
Principle #34Discarding and recovering

Data Source

PatentEP3711448B1Mac reset procedures
Publication Date: 2021.06.09 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3711448B1 patent drawingFigure 1
  • EP3711448B1 patent drawingFigure 2
  • EP3711448B1 patent drawingFigure 3

AI summary

According to an aspect, a wireless device is configured to selectively operate in one or more bandwidth parts, BWPs, configured by the wireless communication network. In some embodiments, the wireless device detects (302) a reset event triggering a reset of a Medium Access Control, MAC, entity in the wireless device, and, responsive to detecting the reset event, resets (304) a counter that tracks beam failure indications.