Satellite-Terrestrial Frequency Sharing With Orthogonal Signal Coding

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Solution Overview

Problem

Co-channel interference occurs when satellite and terrestrial base stations use the same frequency band, leading to reduced signal quality and communication loss for user equipment at the edge of their overlapping coverage areas.

Innovation Solution

Implementing orthogonal spread spectrum coding for satellite signals to spread them across a wider frequency band, while terrestrial base stations communicate without coding, maintaining signal orthogonality and minimizing interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If satellite and terrestrial base stations use the same frequency band to communicate with user equipment, then spectrum utilization is improved, but co-channel interference increases leading to reduced signal quality

Engineering Contradiction:

Improvespectrum utilizationVSAvoidco-channel interference

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different signal characteristics (coded vs. uncoded) to different base station types (satellite vs. terrestrial) operating in the same frequency band. Satellite base stations transmit coded signals while terrestrial base stations transmit uncoded signals, creating local differentiation that allows coexistence without severe interference.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the signal parameter (coding) for satellite base stations while keeping terrestrial base station signals unchanged. This parameter differentiation in the signal domain enables frequency reuse between satellite and terrestrial networks by transforming the satellite signal into a form that is less susceptible to interference.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If orthogonal spread spectrum coding is applied to satellite signals, then co-channel interference is reduced, but signal processing complexity increases

Engineering Contradiction:

Improveco-channel interferenceVSAvoidsignal processing complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the base station population into two distinct groups: satellite base stations that apply orthogonal spread spectrum coding and terrestrial base stations that do not. This segmentation allows each group to use optimized signal processing appropriate to their characteristics while maintaining overall system compatibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The orthogonal code acts as an intermediary transformation that modifies satellite signals before transmission. This intermediate coding step enables the satellite signals to coexist with terrestrial signals in the same frequency band by creating orthogonal signal spaces.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250365030A1Coordinated frequency sharing between satellite and terrestrial radio access networks

Publication Date: 2025.11.27 T MOBILE INNOVATIONS LLC

AI summary

Embodiments of the present disclosure are directed to systems and methods for avoiding or mitigating co-channel interference between terrestrial and satellite radio access networks (RANs). The systems and methods comprise one or more terrestrial base stations and one or more satellite base stations, each configured to transmit signals across overlapping frequency bands. The system further comprises applying an orthogonal spread spectrum code to the signals transmitted by the satellite base station, while the terrestrial base station transmits without such coding.