LTE and 5G Subframe Synchronization for Interference Avoidance

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The challenge is to enable the coexistence of LTE and 5G communication systems within the same radio coverage area without interference, particularly in scenarios where frequency bands are limited or user terminals cannot support additional frequency bands, and where a complete transition from LTE to 5G is not feasible due to slow adoption.

Innovation Solution

The method involves synchronizing eNB and gNB base stations on a subframe level, using overlapping frequency bands for downlink and uplink communications, dynamically negotiating subframe sizes based on data traffic volume, and sharing coinciding subframes for random-access transmissions, allowing LTE and 5G systems to operate within the same frequency range without interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LTE and 5G systems use separate frequency bands, then interference between systems is avoided, but bandwidth utilization is reduced and user terminals cannot support additional frequency bands

Engineering Contradiction:
Improveinterference avoidanceVSAvoidbandwidth utilization
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The system divides the frequency band into different subframes, allocating specific subframes to LTE and 5G systems respectively. This time-domain segmentation allows both systems to operate in the same frequency band without interfering with each other, while maximizing bandwidth utilization.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from frequency-domain separation to time-domain separation by introducing subframe-based resource allocation. This dimensional change allows coexistence of LTE and 5G in the same frequency band through temporal multiplexing.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If LTE is completely replaced by 5G, then the network is modernized, but the slow transition of user terminals makes this infeasible

Engineering Contradiction:
Improvenetwork modernizationVSAvoidtransition speed
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The system dynamically negotiates and adjusts the number of subframes allocated to each system based on current traffic conditions and user terminal capabilities. This dynamic resource allocation allows the network to adapt to the gradual transition pace while maintaining optimal performance for both legacy and modern terminals.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of resource allocation from static frequency separation to dynamic time-domain subframe allocation. This allows flexible adjustment of LTE and 5G resource distribution according to transition progress and traffic demands.

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If LTE and 5G share the same frequency band with overlapping subframes, then bandwidth is maximized, but interference between systems occurs

Engineering Contradiction:
Improvebandwidth usageVSAvoidinterference-free operation
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The system segments the time domain into distinct subframes, assigning specific subframes to LTE and 5G systems. This prevents overlapping transmissions in the same frequency band, eliminating interference while maintaining high bandwidth utilization through efficient time multiplexing.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If subframe sizes are fixed for LTE and 5G, then system operation is simplified, but resource allocation cannot adapt to varying traffic volumes

Engineering Contradiction:
Improvesystem operation simplicityVSAvoidtraffic adaptation
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The system implements dynamic subframe size negotiation between LTE and 5G systems based on real-time traffic conditions. This allows the network to adapt resource allocation to varying traffic demands while maintaining relatively simple operational procedures through automated negotiation protocols.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3811681B1Method for operating LTE and 5g communication systems in an overlapping radio coverage area
Publication Date: 2022.11.09 KONTRON TRANSPORTATION FRANCE SAS
  • EP3811681B1 patent drawingFigure 1
  • EP3811681B1 patent drawingFigure 2~3

AI summary

A method for operating a first LTE communication system (1) and a second 5G communication system (2) for communication between a user terminal and an eNB base station (5) of the first communication system and a gNB base station (6) of the second communication system, wherein each of the eNB and gNB base stations communicates downlink data over a sequence of downlink radio frames and uplink data over a sequence of uplink radio frames, the downlink as well as the uplink radio frames (Fj, Hk) each comprising a predetermined number of subframes (SFi), wherein the eNB and gNB base stations (5, 6) are synchronized on a subframe level and use overlapping frequency bands, wherein, at least for the downlink radio frames (Fj, Hk), the eNB base station (5) uses a first set of subframes (SFi) and the gNB base station (6) uses a second set of subframes (SFi), which first and second sets of subframes (SFi) do not overlap during communication (14, 15), and wherein the sizes of the first and second sets are dynamically negotiated between the eNB and gNB base stations (5, 6) in response to a current or estimated data traffic volume over the eNB base station (5) and the gNB base station (6), respectively.