Base Station Scheduling for Coexisting OFDM Systems

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Solution Overview

Problem

Existing radio communication systems do not optimize the use of frequency bands when a new system replaces a legacy system, leading to suboptimal usage at the beginning and end of the new system's operation, and lack backward compatibility.

Innovation Solution

A method for scheduling terminals from both systems in a common frequency band, where the new system dynamically allocates resources based on user demand, using OFDM/OFDMA techniques, allowing cooperative resource sharing in both the frequency and time domains, and ensuring backward compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a new frequency band is chosen for the new system to separate operations, then legacy system and new system operations are well separated, but frequency band usage is not optimized

Engineering Contradiction:
Improvesystem operation separationVSAvoidfrequency band usage efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent merges legacy system and new system operations into a common frequency band, allowing both systems to coexist and share resources. The base station schedules terminals from both systems simultaneously in the same frequency band, optimizing spectrum usage while maintaining operational separation through dynamic resource allocation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent implements dynamic resource allocation where the base station continuously adjusts the amount of resources allocated to legacy and new system terminals based on real-time conditions. The scheduler dynamically determines resource distribution frame by frame, adapting to changing traffic demands and user requirements.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If frequency bands are dimensioned for full capacity of both networks, then both systems can operate at full capacity, but usage is non-optimal when user distribution changes over time

Engineering Contradiction:
Improvefull capacity supportVSAvoidfrequency band utilization
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent implements dynamic resource allocation where the base station continuously adjusts the amount of resources allocated to legacy and new system terminals based on real-time conditions. The scheduler dynamically determines resource distribution frame by frame, adapting to changing traffic demands and user requirements.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the allocation parameters of frequency resources dynamically. The base station adjusts the number of subcarriers, time slots, and code resources allocated to each system based on current user demand, traffic patterns, and system priorities, transforming static frequency planning into adaptive resource management.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the new system operates independently on its own frequency band, then system performance is optimized, but backward compatibility and smooth migration are compromised

Engineering Contradiction:
Improvenew system performanceVSAvoidbackward compatibility
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent makes the base station universal by enabling it to serve both legacy and new system terminals simultaneously. The base station performs multiple functions: it schedules new system terminals with advanced techniques while also supporting legacy terminals with traditional methods, all within the same frequency band infrastructure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The base station acts as an intermediary between the legacy system and the new system. It translates and coordinates resource allocation for both systems, managing the coexistence and enabling smooth migration by controlling which terminals access which resources in each time frame.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Productivity

If legacy terminals are replaced to introduce new systems, then new system performance is improved, but migration complexity and cost increase

Engineering Contradiction:
Improvecommunication system efficiencyVSAvoidmigration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent enables legacy terminals to continue operating without modification while the base station provides enhanced services. The legacy terminals self-service by continuing to use their existing protocols, while the base station independently manages resource allocation to accommodate both legacy and new terminals, eliminating the need for terminal replacement.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent prepares the infrastructure for future migration by implementing a coexistence mode where both legacy and new terminals can operate simultaneously. This preliminary arrangement allows operators to gradually migrate users without forced replacement, reducing complexity and enabling a smooth transition path.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2026616B1Method for scheduling simultaneously terminals in the same frequency band, and corresponding base station
Publication Date: 2010.10.20 ALCATEL LUCENT SA
  • EP2026616B1 patent drawingFigure 1~2
  • EP2026616B1 patent drawingFigure 3~4

AI summary

The present invention relates to a method for scheduling simultaneously terminals belonging to two radio communication systems in a common frequency band, a base station of said first communication system having knowledge of said second radio communication system, both systems using an OFDM resource allocation mechanism on the air interface, an OFDM frame structure being predefined for said first system. According to the present invention, the method comprises the steps of: - detecting in said first system the amount of resources needed for said second system for a predefined time period; - determining a first part of said OFDM frame reserved for said first system and a second part of said OFDM frame reserved for said second system for said predefined time period, said first and second part of said OFDM frame being separated in the frequency domain of and taking into account the resources needed for said second system.