Two-Level Database Architecture for TV White Space Coexistence
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Solution Overview
Problem
The existing technologies face challenges in efficiently managing the TV spectrum for unlicensed applications without interfering with licensed services, particularly in determining available channels and ensuring coexistence among unlicensed devices, due to the lack of a standardized database architecture and coordination mechanism.
Innovation Solution
A two-level database structure is introduced, comprising a central database and local databases, which stores and manages identification and operational parameters for both licensed and unlicensed TV band devices, enabling negotiation of operational parameters and coexistence among unlicensed devices while avoiding the need for a coexistence coordinator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a centralized database is used to manage TV spectrum for unlicensed devices, then coordination and protection of licensed services is improved, but database overload and processing complexity increases
Solution Approach 1:
The database system is segmented into a centralized database component and multiple distributed database components. The centralized database stores licensed service information and provides overall coordination, while distributed databases handle local unlicensed device registrations and spectrum availability data. This segmentation distributes the processing load and reduces the complexity burden on any single database component.
Solution Approach 2:
A database management system acts as an intermediary layer between the centralized and distributed database components. This mediator handles data synchronization, coordinate information exchange, and processing task distribution, thereby reducing direct communication complexity and protecting licensed services through coordinated management.
2Reliability
If all unlicensed devices register with the central database, then spectrum coordination is improved, but the central database becomes overloaded
Solution Approach 1:
The database registration function is segmented between centralized and distributed components. Unlicensed devices first register with local distributed databases, which handle local spectrum coordination. Only essential coordination data is synchronized to the centralized database, significantly reducing the quantity of data and processing load on the central system while maintaining reliable spectrum coordination.
Solution Approach 2:
The system transitions from a single-dimensional centralized registration model to a two-dimensional hierarchical model with both centralized and distributed registration capabilities. This dimensional change allows devices to register locally at the distributed level while still enabling centralized oversight, thereby distributing the registration load and preventing central database overload.
3Productivity
If distributed databases are used for local spectrum management, then coordination efficiency is improved, but system complexity increases
Solution Approach 1:
The spectrum management function is segmented into centralized coordination (for overall spectrum policy and licensed service protection) and distributed execution (for local device registration and channel allocation). This segmentation improves coordination efficiency by enabling local autonomous decision-making while maintaining system-wide coherence through the standardized interface provided by the database management system.
Solution Approach 2:
The database management system provides universal functionality that works across both centralized and distributed components. It handles diverse tasks including device registration, spectrum availability tracking, coordination message routing, and data synchronization through a unified interface, thereby improving coordination efficiency without proportionally increasing system complexity.
Data Source
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AI summary
A two-level database structure for use by unlicensed TVBD devices operating in TV white space comprises a central database and local databases. The central database comprises two sub-database: the central licensed database which maintains information about all licensed TV devices and the central unlicensed database which maintains information about unlicensed wireless devices operating in TV spectrum. The local database is created by each TVBD device or TVBD network when it initiates and it stores information related to all transmitters in the local area, including location, power transmission levels, operating schedule, sensing results, backup channel information. The local databases communicate with central database to query it about licensed usage of TV spectrum and register with central database. The local databases communicate with each other to exchange information about channel usage, sensing results, transmission patterns and other information that will allow the local databases to negotiate coexistence without central coordinator. The locally implemented negotiation prevents the overloading of the central database.