Spatial-Frequency Precoding Coefficient Restriction for Interference Reduction
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Solution Overview
Problem
In frequency division duplexing (FDD) MIMO systems, the downlink precoding vector cannot be estimated based on the uplink channel due to the difference between uplink and downlink frequency bands, leading to interference with neighboring cells when high-power spatial domain beams are used, which degrades system performance.
Innovation Solution
A communication method that restricts the amplitudes and phases of spatial-frequency combination coefficients using threshold-based rules to reduce interference with neighboring cells, by selecting and configuring spatial and frequency domain basis vectors, and reporting only necessary coefficients to the network device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-power spatial domain beams are used to improve signal transmission performance, then communication quality between terminal device and network device is improved, but interference to neighboring cells increases and system performance deteriorates
Solution Approach 1:
The patent applies parameter changes by imposing amplitude constraints on spatial-frequency combination coefficients corresponding to restricted spatial domain beam basis vectors. This modifies the parameter space of precoding vectors, forcing the system to operate within constrained amplitude ranges that reduce interference while maintaining communication quality through optimized coefficient selection.
Solution Approach 2:
The patent implements local quality by applying different amplitude constraints to different spatial domain beam basis vectors based on their directional characteristics. Beams pointing toward neighboring cells receive stricter amplitude restrictions (lower thresholds), while other beams maintain higher amplitude freedom, creating localized quality control across different spatial directions.
2Object-generated harmful factors
If amplitude constraints are imposed on spatial-frequency combination coefficients to reduce interference, then interference to neighboring cells is reduced, but the complexity of determining precoding vectors increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the network device with restricted spatial domain beam basis vector groups and their corresponding amplitude thresholds before precoding operations. This advance preparation stores constraint information in lookup tables or configuration data structures, allowing terminal devices to quickly query and apply appropriate amplitude limits during precoding vector determination without complex real-time calculations.
Solution Approach 2:
The patent introduces an intermediary mechanism through the network device that manages and distributes amplitude constraint information to terminal devices. This intermediary role centralizes the complexity of interference management, allowing terminal devices to simply follow provided constraints rather than independently calculating optimal amplitude limits, thereby reducing overall system complexity.
Data Source
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AI summary
Embodiments of the present invention disclose a communication method and a device. Configuration information indicating one or more spatial domain beam basis vector groups and Q thresholds is received from a network device, where the Q thresholds correspond one-to-one to spatial domain beam basis vectors in the one or more spatial domain beam basis vector groups. L spatial domain beam basis vectors are selected from a spatial domain beam basis vector group set. K frequency domain basis vectors are selected from a frequency domain basis vector set for each of the L spatial domain beam basis vectors. M spatial-frequency combination coefficient vectors are determined based on the L spatial domain beam basis vectors, the K frequency domain basis vectors corresponding to each of the L spatial domain beam basis vectors, and a precoding vector, where spatial-frequency combination coefficients in one spatial-frequency combination coefficient vector corresponding to one spatial domain beam basis vector satisfy a restriction rule, and the restriction rule is associated with a threshold corresponding to the spatial domain beam basis vector. Amplitudes and phases of spatial-frequency combination coefficients in the M spatial-frequency combination coefficient vectors are sent to the network device. The embodiments of the present invention can improve system performance.