Base Station Downlink Interference Cancellation via Backhaul
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Solution Overview
Problem
Modern wireless networks face significant downlink interference from uplink signals due to neighboring base stations transmitting and receiving over common radio resources, particularly when there is a line of sight connection, which existing techniques have not adequately addressed.
Innovation Solution
The implementation of coordinated multipoint (COMP) techniques that involve receiving downlink information from interfering base stations over a backhaul network to remove interference from uplink signals using interference cancellation methods such as signal interference cancellation (SIC) and interference rejection combining (IRC), leveraging channel information to suppress interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If neighboring base stations transmit and receive over common radio resources in full duplex mode, then network resource utilization is improved, but downlink interference from uplink signals increases significantly
Solution Approach 1:
The patent converts the harmful downlink interference from neighboring base stations into a beneficial signal by capturing the downlink information, regenerating the interfering signal, and subtracting it from the received uplink signal. This interference cancellation approach transforms the harmful interference into a useful component that can be removed, thereby improving uplink signal quality while maintaining full duplex operation
Solution Approach 2:
The patent introduces an intermediary processing mechanism where downlink information is exchanged between neighboring base stations through a backhaul network. This intermediary information exchange enables each base station to reconstruct and cancel the interference from neighboring downlink transmissions, effectively mediating the interference problem while preserving full duplex resource utilization
2Reliability
If downlink information is exchanged over backhaul network to cancel interference, then interference cancellation capability is improved, but system complexity increases
Solution Approach 1:
The patent applies preliminary action by obtaining downlink information from neighboring base stations before the interference cancellation process. This advance acquisition of downlink data, transmission mode information, and resource allocation details enables the base station to pre-constrain the interference signal characteristics, making the subsequent cancellation process more effective and straightforward
Solution Approach 2:
The patent implements feedback mechanisms where base stations continuously exchange downlink information over the backhaul network based on current transmission conditions. This feedback loop enables dynamic adaptation of interference cancellation parameters, allowing the system to maintain high cancellation capability while managing complexity through selective information exchange only when interference conditions warrant it
Data Source
AI summary
Base stations (BSs) can remove inter-BS interference components from received uplink signals using downlink information communicated over a backhaul network. The downlink information is associated with downlink transmissions of neighboring base stations, and is used to remove the inter-BS interference in accordance with interference cancellation techniques, e.g., signal interference cancellation (SIC), etc. The downlink information includes information associated with downlink transmission of the interfering BSs, such as information bits (e.g., data), parity information, control information, modulation and coding scheme (MCS) parameters, forward error correction (FEC) parameters, and other information. Additionally, inter-BS interference can be suppressed using channel information of interference channels using interference suppression techniques, e.g., interference rejection combining (IRC), etc.