Relay Station Resource Reuse in Multi-Hop Wireless Networks

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Solution Overview

Problem

Multi-hop wireless communication networks face a capacity penalty due to the need for double resources because relay stations cannot transmit and receive simultaneously, leading to inefficiencies in resource management and increased interference.

Innovation Solution

A resource reuse and assignment scheme that divides relay stations into groups, allowing a single base station to service multiple groups in separate time periods, with frequency bands reused between groups to minimize interference and maximize capacity, using an interference-aware approach for optimal resource allocation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If relay stations are used to extend coverage in multi-hop networks, then the coverage area is improved, but the resource efficiency deteriorates due to the need for double resources

Engineering Contradiction:
Improvecoverage areaVSAvoidresource efficiency
Core Design Contradiction:
Area of stationary objectVSProductivity

Solution Approach 1:

The patent segments relay stations into different groups (first group and second group) that can operate on different frequency bands. This allows simultaneous transmission and reception by dividing the relay station population into subsets that operate semi-independently, thereby improving resource efficiency while maintaining extended coverage capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements periodic switching between different frequency bands for different groups of relay stations. By alternating which group uses which frequency band in a periodic manner, the system achieves time-division multiplexing that allows relay stations to effectively transmit and receive without simultaneous interference, resolving the resource efficiency problem.

Inventive Principle:
Principle #19Periodic action

2Object-affected harmful factors

If relay stations cannot transmit and receive simultaneously, then interference is reduced, but the resource utilization deteriorates due to time-division operation requirements

Engineering Contradiction:
ImproveinterferenceVSAvoidresource utilization
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent introduces a frequency dimension to resolve the transmission-reception conflict. Instead of only time-division, the system uses frequency-division by assigning different frequency bands to different groups of relay stations. This dimensional addition allows simultaneous operation in different frequency domains while maintaining interference avoidance through proper band allocation.

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

Solution Approach 2:

The patent uses frequency bands as an intermediary resource to mediate between transmission and reception operations. By introducing frequency bands as an additional degree of freedom, the system can allocate specific bands for transmission and other bands for reception, allowing relay stations to operate simultaneously without direct interference.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If frequency bands are reused between groups of relay stations, then resource efficiency is improved, but interference management complexity increases

Engineering Contradiction:
Improveresource efficiencyVSAvoidinterference management complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the frequency spectrum into distinct bands and assigns them to different groups of relay stations in a systematic pattern. This structured segmentation simplifies interference management by creating clear frequency boundaries between groups, making it easier to control and predict interference patterns while enabling efficient frequency reuse.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the frequency parameter (band assignment) based on the group identifier of each relay station. By systematically varying the frequency parameter across different groups, the system enables frequency reuse while maintaining manageable interference characteristics through predictable parameter patterns.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1855492B1Method, apparatus and system for reusing resources in a telecommunication network using repeaters.
Publication Date: 2008.06.04 NTT DOCOMO INC
  • EP1855492B1 patent drawingFigure 1
  • EP1855492B1 patent drawingFigure 2
  • EP1855492B1 patent drawingFigure 3~4

AI summary

For communicating data between a plurality of receivers (1061-10612) and a transmitter (102) in a wireless communication system, the wireless communication system comprising a plurality of relay stations (1041-1044), wherein at least one of the plurality of relay stations (1041-1044) has assigned thereto at least one receiver (1061-10612), each relay station (1041-1044) relaying data between the transmitter (102) and the assigned receiver (1061-10612) during subsequent communication intervals, data is communicated between the transmitter (102) and different groups of relay stations (1041-1044), wherein each group of relay stations (1041-1044) comprises at least one relay station (1041-1044).