White Space Map for WLAN Primary Service Protection
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Solution Overview
Problem
Existing WLAN technologies face challenges in efficiently operating unlicensed devices in TV White Spaces (TVWS) without interfering with licensed devices, particularly in acquiring available channel information and protecting incumbent users.
Innovation Solution
A method and apparatus that utilize a white space map (WSM) to identify available channels and maximum transmission powers, updating the map when primary service signals are detected, and transmitting this information to other stations to ensure they switch channels, thereby protecting primary services and optimizing unlicensed device operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If unlicensed devices perform spectrum sensing to detect incumbent users, then protection of primary services is improved, but operation efficiency and channel availability deteriorate due to scanning time and signaling overhead
Solution Approach 1:
The patent applies preliminary action by having the access point pre-acquire and store white space map information indicating available channels and maximum transmission powers before unlicensed devices need to operate. This pre-prepared information allows stations to immediately determine channel availability without performing time-consuming spectrum sensing, thus protecting incumbent users while maintaining operational efficiency.
Solution Approach 2:
The patent uses the access point as an intermediary that centralizes the spectrum sensing and information acquisition function. Instead of each station independently performing spectrum sensing, the access point acquires white space map information and distributes it to stations, reducing redundant sensing operations and signaling overhead while maintaining reliable protection of primary services.
2Adaptability or versatility
If unlicensed devices acquire available channel information through spectrum sensing, then channel availability is improved, but time consumption and signaling overhead increase
Solution Approach 1:
The patent applies copying by having the access point create a white space map that copies and stores the available channel information and maximum transmission power levels. This copied information is then distributed to stations, allowing them to obtain channel availability data without performing their own time-consuming spectrum sensing operations.
Solution Approach 2:
The access point performs the time-consuming spectrum sensing and information acquisition in advance, storing the results in a white space map. This preliminary action eliminates the need for stations to spend time on scanning, as they can directly use the pre-acquired channel availability information.
3Power
If unlicensed devices use maximum transmission power on available channels, then transmission efficiency is improved, but interference to incumbent users increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the transmission power parameter based on the white space map information. Each station receives maximum allowed transmission power levels for specific channels from the access point and modifies its transmission power accordingly, ensuring optimal power usage while preventing harmful interference to incumbent users.
Solution Approach 2:
The system implements feedback through the white space map mechanism, where the access point continuously monitors channel conditions and updates the maximum transmission power levels in the white space map. This feedback loop ensures that transmission power parameters are adjusted in response to changing conditions, maintaining efficient transmission while protecting incumbent users from interference.
Data Source
AI summary
A method and an apparatus for protecting a primary service as an unlicensed device in a regulatory domain where a licensed device and the unlicensed device are permitted to operate are disclosed. For protecting a primary service by a station as an unlicensed device in a regulatory domain where a licensed device and the unlicensed device are permitted to operate, the unlicensed device acquires a list of identified available channels for the operation of the unlicensed device and maximum allowed transmission powers of the identified available channels from a regulatory domain database system; generates a white space map (WSM) comprising the list of identified available channels and the maximum allowed transmission powers of the identified available channels; updates the WSM when the station acquires information that a primary service signal is detected on a specific channel which is indicated as available in the WSM; and transmits the updated WSM to another station such that the another station moves to another channel if the another station is operating on the specific channel.