Spatial Interference Mitigation via UE Feedback Steering
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Solution Overview
Problem
Wireless communication networks face challenges in mitigating spatial interference on the downlink, which affects data transmission quality due to strong non-serving base stations, leading to reduced performance and increased interference.
Innovation Solution
The method involves user equipment (UE) determining and providing spatial feedback information (SFI) to interfering cells, which use this information to adjust their transmission and reduce interference, employing techniques like channel direction indicators, precoding matrices, and nulling gains to steer transmissions away from the UE, thereby mitigating spatial interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a UE is served by a base station while strong non-serving base stations are present, then the UE can receive data transmission, but the UE experiences high interference from non-serving base stations
Solution Approach 1:
The UE measures downlink channel responses from non-serving base stations and provides spatial feedback information (SFI) back to those base stations. This feedback enables the non-serving base stations to adjust their precoding matrices and steer nulls toward the UE, thereby reducing interference while maintaining data transmission performance.
Solution Approach 2:
The system proactively mitigates interference by having the UE measure and report channel responses from non-serving base stations before interference severely degrades performance. The non-serving base stations use this advance information to pre-adjust their beamforming strategies and prevent harmful interference from reaching the UE.
2Area of stationary object
If non-serving base stations transmit data, then network coverage is extended, but interference to served UEs increases
Solution Approach 1:
Each non-serving base station applies local spatial processing by adjusting its precoding matrix based on channel responses from specific UEs. This enables the base station to transmit data over extended coverage areas while simultaneously creating localized nulls in the directions of served UEs, thus extending coverage without proportionally increasing interference.
3Object-affected harmful factors
If the UE provides spatial feedback information to interfering cells, then interference is reduced, but signaling overhead increases
Solution Approach 1:
The spatial feedback information comprises parameters such as channel direction indicators (CDI) and precoding matrix indicators (PMI) that concisely represent the spatial channel characteristics. By using these compressed parameter representations rather than full channel matrices, the system achieves effective interference reduction while minimizing the signaling overhead required to convey the feedback information.
Data Source
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AI summary
Techniques for transmitting and receiving data with spatial interference mitigation in a wireless network are described. In one design of transmitting data with spatial interference mitigation, a first station (e.g., a cell) may receive spatial feedback information (SFI) from a second station (e.g., an interfered UE) that is not communicating with the first station. The second station may also receive precoding information from a third station (e.g., a served UE). The first station may send a data transmission to the third station based on the precoding information and the SFI in order to reduce interference to the second station. In one design, the SFI may include spatial nulling information. The first station may send the data transmission based on the spatial nulling information to steer the data transmission in a direction away from the second station.