PON-OLT Synchronization with LTE Discontinuous Reception

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Solution Overview

Problem

In a system combining LTE and PON systems, the scheduler cannot predict the recovery waiting time in the PON section, leading to wasteful retransmissions of downlink data during discontinuous reception and sleep operations, causing inefficient use of transmission capacity.

Innovation Solution

The OLT in the PON system obtains information on the discontinuous reception of UE from the BBU, adjusting the sleep start timing and cycle of the ONU to minimize the recovery waiting time for downlink data, ensuring synchronized sleep and recovery states across both systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the scheduler operates independently in each system (LTE and PON), then the system operation is simple and independent, but the recovery waiting time cannot be predicted leading to wasteful retransmissions

Engineering Contradiction:

Improvescheduler operation complexityVSAvoiddownlink data transmission reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent merges the scheduling operations of LTE and PON systems by having the PON scheduler acquire discontinuous reception information from the LTE scheduler. This integration allows the PON scheduler to predict recovery waiting times and coordinate sleep/wake cycles with LTE transmissions, eliminating wasteful retransmissions while maintaining manageable system complexity through standardized information exchange protocols

Inventive Principle:

Principle #5Merging (Combining)

2Use of energy by moving object

If the ONU enters sleep state to save power, then power consumption is reduced, but the recovery waiting time causes transmission capacity waste

Engineering Contradiction:

Improvepower consumptionVSAvoidtransmission capacity utilization

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent applies preliminary action by having the PON scheduler acquire discontinuous reception information in advance from the LTE scheduler before the ONU enters sleep state. This allows the PON system to predict when the UE will wake up and proactively prepare downlink data transmissions, ensuring the ONU wakes up at the optimal time to receive data without causing transmission capacity waste

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where the PON scheduler continuously monitors and acquires discontinuous reception information from the LTE scheduler. This feedback loop enables dynamic adjustment of the ONU's sleep and wake cycles to match LTE transmission schedules, optimizing both power consumption and transmission capacity utilization

Inventive Principle:

Principle #23Feedback

3Use of energy by moving object

If the UE performs discontinuous reception to save power, then power consumption is reduced, but the scheduler cannot predict recovery timing causing retransmissions

Engineering Contradiction:

Improvepower consumptionVSAvoidretransmission time

Core Design Contradiction:

Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent implements feedback by having the PON scheduler acquire discontinuous reception information from the LTE scheduler, including wake-up timing and cycle parameters. This feedback enables the PON system to predict exactly when the UE will be awake and ready to receive data, eliminating unpredictable retransmission delays while the UE maintains its power-saving discontinuous reception mode

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS9693302B2Optical wireless access system

Publication Date: 2017.06.27 NIPPON TELEGRAPH & TELEPHONE CORP

AI summary

An OLT of a PON obtains information on discontinuous reception of a UE from a BBU of LTE, and adjusts a sleep start timing and a sleep cycle of an ONU so that a recovery waiting time in the OLT with respect to downlink data transmitted from the BBU to the UE can be minimized.