Split Bearer Flow Control Using Expected Queuing Times

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Solution Overview

Problem

In cellular networks, especially in LTE systems with dual connectivity, there is a challenge in efficiently managing queuing times and delays across internode interfaces between Master eNodeB and Secondary eNodeB, which affects the flow control of Packet Data Convergence Protocol (PDCP) Packet Data Units, leading to suboptimal data transmission and potential bottlenecks.

Innovation Solution

The method involves obtaining and determining expected queuing times at both network nodes and adjusting buffer queuing times based on internode interface delays to optimize the forwarding of PDCP PDUs, ensuring they are sent only if the queuing time at the Master eNodeB is greater than the sum of the downlink delay and queuing time at the Secondary eNodeB, thereby balancing data flow and minimizing delays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If flow control is performed in a split bearer environment with dual connectivity, then data transmission reliability is improved, but queuing times and delays increase due to internode interface processing

Engineering Contradiction:

Improvedata transmission reliabilityVSAvoidqueuing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by obtaining expected queuing times in advance at both MeNB and SeNB before making forwarding decisions. The MeNB calculates the expected queuing time at the SeNB based on feedback information and uses this pre-obtained time estimate to determine the optimal forwarding path, thereby reducing actual queuing delays in the data transmission path.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements dynamics by continuously adapting the flow control mechanism to changing network conditions. The MeNB dynamically adjusts forwarding decisions based on real-time feedback information including queue data volumes, service rates, and internode interface delays. This dynamic adaptation allows the system to optimize the balance between reliability and queuing time according to current network state.

Inventive Principle:

Principle #15Dynamics

2Productivity

If data is forwarded through the internode interface to the Secondary eNodeB, then load balancing is improved, but transmission delays increase due to additional routing steps

Engineering Contradiction:

Improveload balancing efficiencyVSAvoidtransmission delay

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent applies dynamics by making real-time forwarding decisions based on current network conditions. The MeNB continuously monitors expected queuing times, internode interface delays, and service rates to dynamically determine whether to forward data through the SeNB or transmit directly to the UE. This dynamic approach optimizes the balance between load balancing benefits and transmission delay penalties.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by using multiple variables in the forwarding decision process, including expected queuing time at MeNB, expected queuing time at SeNB, internode interface delay, queue data volumes, and service rates. By changing and evaluating these parameters in real-time, the system determines the optimal forwarding path that balances load while minimizing delay.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If flow control feedback is implemented between Master eNodeB and Secondary eNodeB, then data flow balancing is improved, but system complexity increases due to additional signaling

Engineering Contradiction:

Improvedata flow balancingVSAvoidsystem complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent implements feedback by establishing a flow control mechanism where the SeNB sends feedback information to the MeNB about its current state (queue data volume, service rate). The MeNB uses this feedback to calculate expected queuing times and make informed forwarding decisions. This feedback loop enables effective data flow balancing while keeping the complexity localized to the control plane rather than the data plane.

Inventive Principle:

Principle #23Feedback

4Productivity

If expected queuing times are obtained and used for forwarding decisions, then transmission efficiency is improved, but measurement and calculation complexity increases

Engineering Contradiction:

Improvetransmission efficiencyVSAvoidqueuing time measurement complexity

Core Design Contradiction:

ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies preliminary action by obtaining expected queuing times in advance through calculations based on feedback information from the SeNB. Rather than measuring actual queuing times in real-time during data transmission, the system pre-calculates expected values using queue data volumes and service rates, thereby simplifying the measurement complexity while maintaining transmission efficiency.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS11800395B2Method, system and device for providing flow control in a split bearer environment

Publication Date: 2023.10.24 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

There is disclosed a method in a first network node operating in a split bearer environment, the first network node being communicatively connected with a second network node via an internode interface. The method comprises obtaining, by the first network node, expected queuing times of packet data convergence protocol (PDCP) packet data units (PDUs) at the first network node and at the second network node. The method comprises determining, by the first network node and according to the estimated expected queuing times, forwarding of a flow of PDCP PDUs destined for a User Equipment (UE).