Synchronous Spectrum Sharing via OFDM Idle Slot Detection

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Solution Overview

Problem

Conventional spectrum allocation schemes lead to significant under-utilization and inefficiencies in dynamic spectrum access networks, particularly in multiple access wireless networks like WiMAX with OFDMA signaling, due to static channel assumptions and lack of dedicated subchannels for private network users.

Innovation Solution

A synchronous spectrum sharing system based on OFDM or OFDMA signaling that includes a frame detector to identify idle spectrum information for secondary user nodes, allowing them to transmit data in unused symbol slots within dedicated network subchannels, ensuring non-interfering access and dynamic spectrum utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fixed spectrum allocation schemes are used, then primary users have guaranteed spectrum access, but spectrum utilization efficiency deteriorates with significant under-utilization

Engineering Contradiction:

Improvespectrum access guaranteeVSAvoidspectrum utilization efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic spectrum allocation where the spectrum allocation map is not fixed but changes based on primary user activity. Secondary users can dynamically access spectrum resources that are currently idle, transforming the static allocation into a dynamic system that adapts to changing conditions, thereby improving utilization efficiency while maintaining primary user guarantees.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of spectrum allocation from fixed to variable. By introducing a spectrum allocation map that tracks primary user activity and dynamically assigns available spectrum to secondary users, the system optimizes the utilization parameter without compromising the reliability of primary user access.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If conventional systems assume static channel availability, then system design is simplified, but the system fails to adapt to dynamic spectrum conditions in OFDMA networks

Engineering Contradiction:

Improvesystem design complexityVSAvoiddynamic spectrum access capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies preliminary action by pre-defining a spectrum allocation map structure and predetermined spectrum resources for secondary users. This preliminary framework simplifies the system design while enabling dynamic adaptation, as the predefined structures guide the dynamic spectrum access process without requiring complex real-time decisions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system transitions from static channel assumptions to dynamic spectrum conditions by implementing a spectrum allocation map that updates based on primary user activity. This dynamic approach allows the system to adapt to changing spectrum conditions in OFDMA networks while maintaining manageable complexity through structured allocation mechanisms.

Inventive Principle:

Principle #15Dynamics

3Device complexity

If conventional systems assume homogeneous channels, then resource allocation is simplified, but the system cannot effectively manage channels with different propagation characteristics and data rates

Engineering Contradiction:

Improveresource allocation complexityVSAvoidspectrum allocation efficiency

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent implements local quality by assigning different spectrum resources to different secondary users based on their specific requirements and channel conditions. The spectrum allocation map provides localized optimization for each user's spectrum assignments, considering individual propagation characteristics and data rate needs, thereby improving overall allocation efficiency without excessive complexity.

Inventive Principle:

Principle #3Local quality

4Productivity

If dedicated subchannels are not provided for private network users, then spectrum is available for general use, but private networks cannot ensure non-interfering access

Engineering Contradiction:

Improvespectrum availabilityVSAvoidnon-interfering access guarantee

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies segmentation by dividing the spectrum into dedicated subchannels for private network users and general spectrum for other uses. This segmentation ensures that private networks have guaranteed non-interfering access through dedicated resources while the remaining spectrum remains available for general utilization, balancing both requirements effectively.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8891455B2Synchronous spectrum sharing by dedicated networks using OFDM/OFDMA signaling

Publication Date: 2014.11.18 SAMSUNG ELECTRONICS CO LTD

AI summary

A system and method for synchronous spectrum sharing for a dedicated network in a wireless communication system based on orthogonal frequency-division multiplexing (OFDM) or orthogonal frequency division multiple access (OFDMA) signaling is disclosed. The system and method includes detecting a frame of a broadcast waveform and extracting idle spectrum information associated with the dedicated subchannel to the secondary user node. The system allows transmitting data from the secondary user node in unused symbol slots identified in the idle spectrum information thereby making efficient use of unused or idle spectrum. Accordingly, secondary users of the wireless communication system can dynamically form ad-hoc mesh network communications in fixed or mobile scenarios.