Base Station Interference Reduction via Cross-Correlation Matrix
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Solution Overview
Problem
Current methods for reducing uplink interference in wireless communication networks, such as those using CoMP, fractional frequency reuse, and ICIC techniques, are inefficient and do not effectively mitigate interference in scenarios involving femto base stations and macro base stations, particularly due to spectral inefficiencies and resource constraints.
Innovation Solution
A method involving a base station that receives reference signal information from both an interfering and an intended transmitter node, creates a cross-correlation matrix, and generates an improved channel transfer function to enhance decoding and resource allocation, allowing for on-demand uncoordinated multipoint interference resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If fractional frequency reuse is used to coordinate UL resources between macrocell and femto base station, then uplink interference is reduced, but spectral efficiency deteriorates due to one base station not scheduling UL resources while the other is using them
Solution Approach 1:
The system performs preliminary actions by having the macro base station transmit downlink reference signals and having the femto base station capture and store these signals in advance. This preliminary capture of reference signals enables the femto base station to later generate channel transfer function estimates for interference resolution without requiring real-time coordination or resource scheduling adjustments, thus maintaining spectral efficiency while reducing uplink interference.
Solution Approach 2:
The patent introduces an intermediary approach by using downlink reference signals as a medium between the macro base station and femto base station. The femto base station captures these reference signals and uses them to estimate channel transfer functions, which then serve as intermediaries to resolve uplink interference. This eliminates the need for direct resource coordination between base stations, maintaining spectral efficiency while achieving interference reduction.
2Object-affected harmful factors
If beamforming is used to coordinate UL resources spatially between base stations, then uplink interference is reduced, but device complexity increases due to significant antenna resources required
Solution Approach 1:
The femto base station creates a copy of the channel transfer function by capturing downlink reference signals from the macro base station and processing them to generate an estimate of the uplink channel. This copied channel information allows the femto base station to perform interference resolution without requiring complex beamforming antenna arrays, thus reducing device complexity while still achieving interference reduction.
Solution Approach 2:
The patent replaces the mechanical beamforming system (requiring multiple antennas and complex spatial coordination) with a signal processing approach. By using captured downlink reference signals to estimate channel transfer functions and apply interference resolution algorithms, the system substitutes physical antenna resources with computational methods, thereby reducing device complexity while maintaining interference reduction effectiveness.
3Object-affected harmful factors
If joint reception is used where both base stations receive the same data from an individual UE using the same subcarriers at the same time, then uplink interference is reduced, but loss of time increases since the resources of both base stations are tied up with the same reception
Solution Approach 1:
The patent extracts the interference resolution capability from the joint reception process. Instead of requiring both base stations to simultaneously receive and process the same uplink signals (which ties up resources), the system extracts channel information through downlink reference signal transmission and processing. The femto base station independently processes captured reference signals to generate channel transfer function estimates, freeing up resources while still achieving interference reduction.
Solution Approach 2:
The system performs preliminary channel estimation by having the macro base station transmit downlink reference signals that the femto base station captures and processes in advance. This preliminary action generates the necessary channel transfer function estimates before uplink reception occurs, eliminating the need for simultaneous joint reception and freeing up resources for other transmissions, thus reducing resource unavailability time.
4Object-affected harmful factors
If HII technique is used to signal future planned transmissions between base stations, then uplink interference is reduced, but productivity deteriorates due to base stations avoiding use of bandwidth resources
Solution Approach 1:
The macro base station performs preliminary action by transmitting downlink reference signals that contain channel information. The femto base station captures these signals in advance and uses them to estimate channel transfer functions for interference resolution. This preliminary exchange of reference signals eliminates the need for continuous HII signaling and resource coordination, allowing base stations to freely utilize bandwidth resources without causing interference, thus maintaining high productivity.
5Object-affected harmful factors
If OI technique is used to report interference levels after exposure has occurred, then uplink interference is reduced, but loss of time increases due to delayed reporting
Solution Approach 1:
The system performs preliminary channel estimation by having the macro base station transmit downlink reference signals that the femto base station captures and processes in advance. This generates channel transfer function estimates before uplink interference occurs, enabling proactive rather than reactive interference resolution. The femto base station can immediately apply these pre-computed estimates to resolve interference without delay, eliminating the time loss associated with post-exposure reporting.
Data Source
AI summary
The disclosure is directed to an interference reduction method used by a base station, and a base station using the same method. In one of the exemplary embodiments, the disclosure is directed to an interference reduction method used by a base station. The method would include not limited to: receiving a first reference signal information associated with an interfering transmitter node; creating a cross-correlation matrix based at least on the first reference signal information and on a second reference signal information, wherein the second reference signal information is associated with an intended transmitter node; and generating an improved channel transfer function by applying the cross-correlation matrix to an estimated channel transfer function, wherein the estimated channel transfer function is associated with a received transmission from the intended transmitter node, and the improved channel transfer function is associated with the received transmission from the intended transmitter node.