TVWS Unlicensed Device Channel Scanning via White Space Map
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Solution Overview
Problem
Existing WLAN technologies face challenges in efficiently operating unlicensed devices in TV White Space (TVWS) by effectively identifying available channels and protecting incumbent users, with current methods requiring extensive channel scanning and signaling overhead.
Innovation Solution
A method and apparatus that utilize a White Space Map (WSM) to identify available channels for unlicensed devices, received from an enabling station, allowing them to operate within specific channels while minimizing scanning time and protecting incumbent users by using geographic location identification and regulatory database access, and incorporating mechanisms for dynamic station enablement and spectrum sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If unlicensed devices perform extensive channel scanning to identify available TVWS channels, then channel availability information can be accurately obtained, but scanning time and energy consumption increase significantly
Solution Approach 1:
The patent applies preliminary action by having enabling stations perform channel availability measurements and store results in a regulatory database before unlicensed devices need to operate. The enabling stations conduct spectrum sensing and generate White Space Maps (WSM) in advance, so when unlicensed devices need to find available channels, they can retrieve pre-computed information from the database rather than performing extensive scanning themselves, thus resolving the contradiction between accurate channel information and scanning time
Solution Approach 2:
The patent introduces an intermediary mechanism - the regulatory database and enabling stations - that mediates between the need for accurate channel information and the desire to minimize scanning time. Instead of unlicensed devices directly scanning all channels, they query the intermediary database which has already performed the measurement work, effectively transferring the measurement function from end devices to dedicated enabling stations
2Reliability
If unlicensed devices scan all channels to protect incumbent users, then incumbent user protection is ensured, but signaling overhead and system complexity increase
Solution Approach 1:
The patent extracts the incumbent user protection function from individual unlicensed devices and consolidates it into enabling stations. The enabling stations perform spectrum sensing to detect incumbent users and maintain this information in the regulatory database. Unlicensed devices then rely on the pre-assessed channel availability information from the database, which already accounts for incumbent user locations, thereby ensuring protection while reducing system complexity
Solution Approach 2:
The enabling stations perform self-service by autonomously conducting spectrum sensing, identifying incumbent users, and updating the regulatory database with channel availability information. This self-service mechanism eliminates the need for continuous coordination and signaling between unlicensed devices and incumbent users, reducing system complexity while maintaining reliable protection
3Loss of information
If unlicensed devices access regulatory database independently, then channel information can be obtained, but all devices requiring database access capability increases device complexity and cost
Solution Approach 1:
The patent applies universality by designing the system so that enabling stations perform the specialized function of database access and channel assessment, while unlicensed devices perform their primary WLAN functions. The enabling stations serve multiple purposes: they are WLAN access points, they maintain regulatory database information, and they enable multiple unlicensed devices to operate without each device needing full database access capability, thus reducing individual device complexity while ensuring information availability
Data Source
AI summary
A method and an apparatus for scanning existing networks in TV White Space are disclosed. For scanning existing networks at a station to operate as an unlicensed device in a regulatory domain where a licensed device and the unlicensed device are permitted to operate, the method comprises: receiving a white space map (WSM) comprising information for available channels to be used for the unlicensed device to operate a wireless local area network (WLAN) operation and maximum transmission powers allowed for each of the available channels from an enabling station, wherein the enabling station is a station determining the available channels at its location using its own geographic location identification and a regulatory database access capability; and scanning the existing networks on the available channels identified within the received WSM.