LTE Base Station Interference Mitigation via Subframe Notification
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LTE systems, channel quality measurement accuracy is deteriorated due to data interference from other cells, particularly when CSI-RS is multiplexed at low density and over long periods, necessitating effective interference mitigation measures, especially with the consideration of inter-cell coordination techniques like CoMP.
Innovation Solution
A radio base station apparatus and mobile terminal apparatus system that generates and transmits notification information including subframe information of both the serving cell and adjacent cells, allowing the mobile terminal to measure channel quality using this information, thereby implementing other-cell interference mitigation measures within the context of inter-cell coordination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CSI-RS is multiplexed at low density and over long period to improve channel quality measurement capability, then measurement capability is improved, but measurement accuracy deteriorates due to data interference from other cells
Solution Approach 1:
The patent applies preliminary anti-action by having the radio base station proactively notify the mobile terminal of muting positions in other cells before channel quality measurement. This allows the mobile terminal to pre-know which resource elements will contain interfering data from other cells and exclude them from measurement, thereby preventing interference rather than reacting to it after measurement.
Solution Approach 2:
The patent implements preliminary action by transmitting muting notification information containing subframe information of other cells before the actual channel quality measurement takes place. This advance information allows the mobile terminal to prepare the measurement process by identifying and excluding interfering resource elements, ensuring accurate measurement of the serving cell's CSI-RS.
2Reliability
If muting is performed to protect CSI-RS from other-cell interference, then interference mitigation is achieved, but device complexity increases due to inter-cell coordination requirements
Solution Approach 1:
The patent uses an intermediary approach by introducing a notification mechanism that mediates between cells. Instead of direct complex coordination between multiple base stations, the system uses standardized signaling to convey muting information. The radio base station acts as an intermediary that receives muting information and forwards it to mobile terminals, simplifying the coordination complexity while maintaining reliable interference protection.
3Measurement precision
If notification information of subframe information for both serving cell and other cells is transmitted, then channel quality measurement accuracy is improved, but loss of information increases due to additional signaling overhead
Solution Approach 1:
The patent applies universality by designing the notification information structure to serve multiple functions simultaneously. The same notification message conveys both the serving cell's subframe information and other cells' muting information, allowing a single signaling transmission to provide comprehensive measurement guidance without requiring separate dedicated signals for each type of information.
Data Source
AI summary
Provided are a radio base station apparatus, a mobile terminal apparatus and a radio communication method capable of taking other-cell interference mitigation measures even in consideration of inter-cell coordination like CoMP. The radio communication method according to the present invention is characterized by, in a radio base station apparatus, generating notification information including subframe information of a serving cell and subframe information of another cell; and transmitting the notification information to a mobile terminal apparatus connected to the serving cell as a connected cell; and in the mobile terminal apparatus, receiving the notification information including the subframe information of the connected cell and the subframe information of another cell; and measuring channel quality of the connected cell with use of the subframe information of the connected cell and measuring channel quality of another cell with use of the subframe information of another cell.