LAA-LTE Synchronization Channel Structure for Unlicensed Spectrum

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Interference in the unlicensed spectrum poses challenges for LTE communications, as devices competing for the same band can cause co-channel interference and data collisions, particularly when LAA-LTE and WiFi access points operate simultaneously.

Innovation Solution

The implementation of a small cell design with a LAA-LTE access point that transmits synchronization data over frequency channels in the unlicensed band, using synchronization signals like PSS, SSS, and MIB to coordinate data transmissions, dynamically determining transmission times to avoid interference, and integrating with WiFi access points to manage channel allocation and scheduling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If LAA-LTE and WiFi access points operate simultaneously in the unlicensed spectrum, then bandwidth utilization is improved, but interference and data collisions increase

Engineering Contradiction:

Improvebandwidth utilizationVSAvoidinterference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary actions by transmitting synchronization signals (PSS, SSS, MIB) before actual data transmissions. These synchronization signals establish timing and frequency references in advance, allowing devices to coordinate their transmissions and avoid collisions. The synchronization process prepares the channel state beforehand, enabling subsequent coordinated uplink transmissions without interference.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements dynamic transmission timing adjustment based on synchronization data. Devices dynamically determine their transmission times relative to the synchronization signals received from the eNodeB. This dynamic timing coordination allows multiple devices to share the unlicensed spectrum efficiently by transmitting at different time instances, thereby reducing interference while maintaining high bandwidth utilization.

Inventive Principle:

Principle #15Dynamics

2Reliability

If synchronization signals are transmitted frequently to coordinate transmissions, then transmission coordination is improved, but channel occupation time increases

Engineering Contradiction:

Improvetransmission coordinationVSAvoidchannel occupation time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system employs periodic transmission of synchronization signals at optimized intervals rather than continuous transmission. The eNodeB transmits synchronization signals (PSS, SSS, MIB) periodically in a structured manner, providing just enough coordination information to maintain reliable transmissions without unnecessarily occupying the channel. This periodic approach balances coordination reliability with efficient channel utilization.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS9867154B2Synchronization channel structure for a shared channel

Publication Date: 2018.01.09 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

A method includes transmitting, at an LTE device configured to transmit data over an unlicensed band, first synchronization data over a first frequency channel of the unlicensed band during a timeframe. The method further includes transmitting, at one of the first LTE device or a second LTE device, second synchronization data over a second frequency channel of the unlicensed band during the same timeframe. The data transmissions of at least one of the first LTE device or the second LTE device are coordinated based on the synchronization data.