Buffer Status Report for Deadlock-Free Handover

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Solution Overview

Problem

In 4G wireless communication systems, the Buffer Status Report (BSR) does not accurately account for Packet Data Convergence Protocol (PDCP) status reports, leading to transmission delays, packet losses, and deadlocks during handovers, as it fails to consider header compression feedback and missing PDCP data, resulting in inefficient resource allocation and Quality of Service (QoS) issues.

Innovation Solution

A method for generating and transmitting a BSR that includes PDCP control information, such as header compression control and PDCP status reports, to accurately reflect data availability during handovers, ensuring timely and lossless data transmission by considering all relevant data packets and feedback.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the BSR is calculated only based on application layer data packets, then the resource allocation process is simple, but the BSR accuracy is insufficient and cannot reflect actual transmission requirements including PDCP status reports

Engineering Contradiction:

ImproveBSR accuracyVSAvoidresource allocation complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines application layer data packet information with PDCP layer status report information into a unified BSR calculation framework. The BSR now reflects both upper layer data availability and lower layer transmission status, providing comprehensive resource allocation information without requiring separate reporting mechanisms.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The BSR mechanism is enhanced to serve multiple functions simultaneously: it reports application layer data buffer status, PDCP layer transmission status, and handover-related packet information. This multi-functional BSR eliminates the need for separate reporting protocols while improving resource allocation accuracy.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If the BSR reports zero data availability when no application data exists, then the resource allocation is efficient, but a deadlock situation occurs where PDCP status reports cannot be transmitted

Engineering Contradiction:

Improveresource allocation efficiencyVSAvoidhandover reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent ensures that PDCP status reports are prepared and buffered in advance before handover completion. The BSR calculation proactively includes PDCP status information even when application data is absent, ensuring that resources are allocated for status report transmission before the actual handover occurs, thus preventing deadlock situations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms where PDCP layer status information is continuously monitored and fed into the BSR calculation process. This feedback loop ensures that even when application data buffer is empty, the BSR reflects the presence of PDCP status reports requiring transmission, preventing resource allocation deadlocks during handover.

Inventive Principle:

Principle #23Feedback

3Ease of manufacture

If the PDCP status report is not considered for BSR, then the BSR calculation is straightforward, but data loss occurs and retransmission cannot be performed timely

Engineering Contradiction:

ImproveBSR calculation simplicityVSAvoiddata loss

Core Design Contradiction:

Ease of manufactureVSLoss of information

Solution Approach 1:

The patent merges PDCP status report information with application data buffer status in the BSR calculation process. By combining these previously separate information sources, the system achieves comprehensive data availability reporting while maintaining a unified, relatively simple calculation framework that prevents data loss during handover.

Inventive Principle:

Principle #5Merging (Combining)

4Speed

If grants are allocated based on inaccurate BSR, then resource allocation is fast, but transmission delays occur and Quality of Service deteriorates

Engineering Contradiction:

Improveresource allocation speedVSAvoidtransmission delay

Core Design Contradiction:

SpeedVSLoss of time

Solution Approach 1:

The enhanced BSR mechanism provides multi-functional information including application data status, PDCP transmission status, and handover packet information. This comprehensive reporting enables the network to allocate resources accurately and timely, preventing transmission delays while maintaining fast resource allocation through a unified reporting process.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS9860806B2Method and system for computing and sending resource requests and avoiding deadlock situations in mobile communication system

Publication Date: 2018.01.02 SAMSUNG ELECTRONICS CO LTD

AI summary

Disclosed is a method for transmitting a buffer status report (BSR) by a terminal performing a handover procedure from a first network element to a second network element in a mobile communication system, including identifying a data packet available for transmitting and packet data convergence protocol (PDCP) control information, generating a BSR based on the data packet and the PDCP control information, the PDCP control information including header compression control information and a PDCP status report indicating which PDCP data is missing, and transmitting the generated BSR to the second network element, wherein the PDCP status report is transmitted to the second network element based on the BSR as a first PDCP PDU during the handover procedure performed by the terminal.