Small Cell Sub-Frame Blanking for eMBMS Interference
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Solution Overview
Problem
Small cell devices, such as femtocells and picocells, often lack synchronization information and may interfere with base station eMBMS transmissions by using the same sub-frames reserved for eMBMS, leading to interference issues.
Innovation Solution
Small cell devices receive interference information from a receiver device or an interference information feed, identifying base station sub-frames used for eMBMS transmissions and selectively blank corresponding sub-frames to prevent interference, allowing them to transmit without interfering with base station eMBMS communications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If small cell devices transmit using the same sub-frames as base station eMBMS transmissions, then small cell device transmission capacity is improved, but interference with base station eMBMS transmissions occurs
Solution Approach 1:
The small cell device receives interference information in advance that identifies which sub-frames are reserved for base station eMBMS transmissions. Based on this advance information, the small cell device proactively selects and blanks the corresponding sub-frames before transmission, preventing interference from occurring in the first place
Solution Approach 2:
The harmful transmitting sub-frames are extracted and removed from the small cell device's transmission schedule by blanking them. This separates the interfering transmissions from the non-interfering ones, allowing the small cell device to maintain transmission capacity on non-conflicting sub-frames while eliminating interference on eMBMS sub-frames
2Object-affected harmful factors
If small cell devices blank sub-frames to avoid interference, then interference with base station eMBMS transmissions is reduced, but small cell device transmission capacity decreases
Solution Approach 1:
Instead of blanking all sub-frames, the small cell device applies partial action by selectively blanking only those specific sub-frames that are identified as being used for base station eMBMS transmissions. This partial blanking approach minimizes the impact on overall transmission capacity while still achieving the interference reduction goal
3Device complexity
If small cell devices lack synchronization information, then device complexity is reduced, but ability to avoid interference with base station transmissions deteriorates
Solution Approach 1:
An interference information feed acts as an intermediary that provides the small cell device with the synchronization information it needs to identify eMBMS sub-frames. Instead of requiring the small cell device to independently acquire and process complex synchronization information from base stations, the intermediary feed delivers pre-processed interference information in a simplified format
Data Source
AI summary
A device may receive information identifying a first sub-frame being transmitted by a base station via a first radio frame. The first sub-frame may be reserved for providing a particular set of transmissions. The device may identify a second sub-frame, that is to be transmitted by the device via a second radio frame and that corresponds to the first sub-frame. The second sub-frame being included in a second radio frame. The device may blank the second sub-frame based on identifying the second sub-frame that corresponds to the first sub-frame. The device may transmit the second radio frame with the blanked second sub-frame.