802.11 WLAN TV White Space Coexistence

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing IEEE 802.11 WLAN standards face challenges in efficiently utilizing TV white space spectrum due to variable center frequency and channel bandwidth, requiring modifications to ensure coexistence with other wireless systems and maximize spectrum efficiency.

Innovation Solution

The proposed solution extends the IEEE 802.11 MAC and PHY layers to accommodate TV white space characteristics by using an OFDM system with fixed subcarrier spacing, inserting virtual carriers into non-contiguous TV channels, and modifying the EDCA mechanism for quality of service and coexistence, enabling efficient operation in TV white space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional 802.11 WLAN standards are used, then device compatibility and ease of operation are maintained, but spectrum efficiency and adaptability to variable TV white space characteristics deteriorate

Engineering Contradiction:

Improveadaptability to variable center frequency and channel bandwidthVSAvoidcomplexity of MAC and PHY layer modifications

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the OFDM system parameters including fixed subcarrier spacing, variable channel bandwidth support, and adjustable center frequency to adapt to TV white space characteristics. The MAC layer parameters such as EDCA settings are also adjusted to optimize performance for heterogeneous system coexistence in TVWS environments.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If virtual carriers are inserted into non-contiguous TV channels, then spectrum efficiency is improved, but device complexity and signal processing requirements increase

Engineering Contradiction:

Improvespectrum efficiencyVSAvoidcomplexity of signal processing and virtual carrier insertion

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Virtual carriers are inserted as intermediary elements into non-contiguous TV channels to enable efficient spectrum utilization. These virtual carriers act as placeholders that maintain the OFDM signal structure while allowing the system to operate across fragmented spectrum opportunities, effectively bridging the gaps between available white space channels.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If EDCA mechanism is extended for QoS and coexistence, then quality of service and system coexistence are improved, but MAC layer complexity increases

Engineering Contradiction:

Improvequality of service and system coexistenceVSAvoidcomplexity of EDCA mechanism extensions

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The EDCA mechanism is extended with dynamic parameters that allow adaptive adjustment of QoS settings and coexistence behavior. The system dynamically modifies EDCA parameters such as contention window sizes, transmission opportunities, and priority levels based on channel conditions and coexistence requirements, enabling flexible adaptation to heterogeneous wireless systems in TV white space.

Inventive Principle:

Principle #15Dynamics

4Ease of operation

If OFDM with fixed subcarrier spacing is used, then partial reception is simplified and robustness is improved, but adaptability to different channel bandwidths requires additional processing

Engineering Contradiction:

Improvesimplicity of partial receptionVSAvoidadaptability to variable channel bandwidth

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The OFDM signal is segmented with fixed subcarrier spacing that allows receivers to efficiently process partial bandwidths. By maintaining consistent subcarrier spacing across different channel bandwidths, the system enables simplified partial reception where receivers can selectively process only the necessary subcarriers corresponding to available white space channels, reducing processing complexity while maintaining adaptability.

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach allows for effective coexistence of heterogeneous systems, increases throughput, and enhances spectrum efficiency by supporting variable channel bandwidths and non-contiguous channel usage, simplifying partial reception and coexistence schemes.

Implementation Method 1

transmission of this formatted data using orthogonal frequency division multiplexing with fixed subcarrier spacing

Methodology Applied

Scientific EffectOrthogonal Frequency Division Multiplexing (OFDM):

Data Source

PatentUS9185455B2Method and apparatus for using 802.11 WLANs in TV white space

Publication Date: 2015.11.10 INTERDIGITAL MADISON PATENT HLDG

AI summary

A method and apparatus for using 802.11 Wireless LANs in TV white space are provided that additionally allows coexistence with non-802.11 devices in the same spectrum space. The method and apparatus extend concepts used in traditional 802.11 applications in the MAC and PHY layers so that WLANs can function over TV white space channels. The method and apparatus also facilitates coexistence of non 802.11 devices and existence with other 802.11 applications by extending the Enhanced Distributed Channel Access mechanism used to provide quality of service. An OFDM system with fixed subcarrier spacing is suggested to accommodate spectrum characteristics (variable center frequency and channel bandwidth) of the TVWS.