Time Slot Allocation for Satellite Beam Interference

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Solution Overview

Problem

In mobile communication systems, there is a challenge in avoiding interference between terrestrial and satellite communication systems, particularly when using a multi-beam antenna configuration, where simple switching control of radio resources is needed to prevent signal interference between beams.

Innovation Solution

A communication terminal apparatus, satellite base station, and base-station control apparatus are designed to allocate non-overlapping time slots for radio communication, ensuring that time slots used by the satellite mobile communication system do not overlap with those of the terrestrial cellular mobile communication system or adjacent satellite beams, facilitating easy control of radio resource switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If time slots are allocated to multiple beams in a satellite mobile communication system, then the coverage area is expanded, but interference occurs between adjacent beams

Engineering Contradiction:
Improvecoverage areaVSAvoidinterference between beams
Core Design Contradiction:
Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies periodic action by allocating different time slots to adjacent beams in a periodic manner. Each beam is assigned specific time slots for transmission, and adjacent beams use different time slots to avoid simultaneous transmission on the same frequency, thereby preventing interference while maintaining expanded coverage across multiple beams.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent segments the time domain by dividing the available time slots into separate allocation groups for different beams. This temporal segmentation allows multiple beams to operate simultaneously without interference by ensuring that adjacent beams transmit in different time periods, thus resolving the contradiction between expanded coverage and interference avoidance.

Inventive Principle:
Principle #1Segmentation

2Object-generated harmful factors

If frequency switching control is used to avoid interference between terrestrial and satellite systems, then interference is avoided, but the control complexity increases

Engineering Contradiction:
Improveinterference between systemsVSAvoidcontrol complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent uses periodic time slot allocation instead of frequency switching control. By assigning different time slots to satellite and terrestrial systems, interference is avoided through temporal separation rather than frequency management, significantly reducing control complexity while maintaining effective interference avoidance.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent introduces time slot allocation as an intermediary mechanism to manage resource distribution between satellite and terrestrial systems. This time-based intermediary approach simplifies control by providing a straightforward scheduling method that avoids the complexity of frequency switching while effectively preventing interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the same frequency is used by multiple beams, then frequency utilization efficiency is improved, but interference between beams occurs

Engineering Contradiction:
Improvefrequency utilization efficiencyVSAvoidinterference between beams
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent resolves this contradiction by implementing periodic time slot allocation where the same frequency can be reused by different beams in different time periods. This allows high frequency utilization efficiency through frequency reuse while preventing beam-to-beam interference through temporal separation, achieving both objectives simultaneously.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent maintains continuous useful action by ensuring that frequency resources are continuously utilized across different beams through time-division multiplexing. While one beam uses a frequency in its allocated time slot, another beam can use the same frequency in a different time slot, maintaining continuous frequency utilization without interference.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3432631B1Communication terminal device, satellite base station, base station control device, and mobile communication system
Publication Date: 2023.06.07 SOFTBANK CORPORATION
  • EP3432631B1 patent drawingFigure 1
  • EP3432631B1 patent drawingFigure 2
  • EP3432631B1 patent drawingFigure 3

AI summary

A communication terminal apparatus, a terrestrial cellular base station and a mobile communication system are provided, which are capable of being shared in a terrestrial cellular mobile communication system and a satellite mobile communication system, and preventing an interference between beams in a satellite mobile communication system while preventing an interference between both systems by a simple switching control of radio resources. Time slots of radio resources are allocated so as not to overlap with each other between the terrestrial cellular mobile communication system and the satellite mobile communication system and so as not to overlap with each other between adjacent beams corresponding to each of two or more beams of the satellite mobile communication system. When locating in a beam area covered by any one of two or more beams of the satellite mobile communication system, a radio communication of the satellite mobile communication system is performed using the time slots allocated to the beam covering the beam area.