D2D Buffer Status Reporting for Resource Allocation

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Solution Overview

Problem

In device-to-device (D2D) communications, feedback not reaching the network node leads to resource allocation mismatches, resulting in increased transmission latency and data loss due to unacknowledged data being retransmitted on unallocated resources.

Innovation Solution

A method where a D2D capable user equipment (UE) determines and reports the amount of unacknowledged data to a network node, allowing for a scheduling assignment to be made for retransmission via a direct link, ensuring sufficient resource allocation for both new and unacknowledged data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the eNB controls resource allocation for D2D transmissions based on feedback from UEs, then resource allocation efficiency is improved, but transmission latency increases when feedback does not reach the eNB

Engineering Contradiction:
Improveresource allocation efficiencyVSAvoidtransmission latency
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the UE report buffer status information to the eNB before actual data transmission occurs. This allows the eNB to pre-allocate resources and prepare scheduling decisions in advance, so when feedback needs to be sent, resources are already reserved and transmission can proceed without waiting for resource allocation negotiations, thus reducing latency while maintaining eNB-controlled efficiency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements a feedback mechanism where the UE sends buffer status reports to the eNB, and the eNB responds with scheduling assignments. This closed-loop feedback system allows the eNB to make informed resource allocation decisions based on actual UE buffer states, improving resource allocation efficiency while enabling the eNB to track and manage retransmissions effectively

Inventive Principle:
Principle #23Feedback

2Productivity

If the eNB allocates resources for D2D retransmissions, then resource management is improved, but data loss occurs when feedback about unacknowledged data is not received

Engineering Contradiction:
Improveresource managementVSAvoiddata loss
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent uses feedback by having the UE report the status of unacknowledged data to the eNB. This allows the eNB to identify which specific data packets need retransmission and allocate resources accordingly, preventing data loss while improving resource management by avoiding allocation for already successfully transmitted data

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies preliminary action by having the UE proactively report buffer status including unacknowledged data information before the eNB needs to allocate retransmission resources. This allows the eNB to prepare resource allocations in advance for identified retransmission needs, ensuring resources are ready when required and preventing data loss due to unavailable resources

Inventive Principle:
Principle #10Preliminary action

3Speed

If D2D UEs transmit data without eNB resource allocation confirmation, then transmission speed is improved, but resource allocation mismatch occurs leading to increased latency

Engineering Contradiction:
Improvetransmission speedVSAvoidtransmission latency
Core Design Contradiction:
SpeedVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the eNB allocate resources in advance based on UE buffer status reports. This allows UEs to transmit data immediately when needed without waiting for real-time resource allocation negotiations, achieving high transmission speed while avoiding latency caused by resource allocation mismatches since resources are pre-reserved

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3225049B1Methods and apparatuses for buffer status reporting for device-to-device communcations
Publication Date: 2020.02.12 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3225049B1 patent drawingFigure 1
  • EP3225049B1 patent drawingFigure 2
  • EP3225049B1 patent drawingFigure 3

AI summary

Embodiments described herein relate to a wireless device (300); a method therein for buffer status reporting; a network node (500) and a method therein for assigning resources. The method for the wireless device (300) comprises: determining (201 ) an amount of data in the buffer to be transmitted in addition to an amount of data previously transmitted but not acknowledged; transmitting (202) a buffer status report to the network node (500), the report including information on the determined amounts; and receiving (203) from the network node (500) a scheduling assignment for enabling the wireless device to transmit of the unacknowledged data and the remaining data in the buffer.