UE Interference Cancellation Using Blind TPR Estimation
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Solution Overview
Problem
In wireless communication systems, especially in LTE-A networks, interference management is challenging due to dense heterogeneous networks, where existing techniques like NAICS rely on known interference parameters, limiting scheduling flexibility and increasing network signaling load, especially in LTE DL subframes with traffic signals.
Innovation Solution
A method for canceling interference in a UE involves generating a random parameter by projecting a received signal onto a set of projection vectors, determining a Traffic to Pilot Ratio (TPR) that minimizes a decision metric, and using this TPR to cancel interference, employing blind detection techniques to estimate interference parameters without relying on network signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If interference parameters are known to UE by broadcasting or dedicated signaling, then interference cancellation performance is improved, but network signaling load and scheduling flexibility are reduced
Solution Approach 1:
The UE autonomously estimates interference parameters (TPR, RI, PMI, MOD) by processing received signals itself, without requiring network signaling. The UE performs blind detection of these parameters and uses them for interference cancellation, making the system self-sufficient and reducing signaling overhead.
Solution Approach 2:
The patent replaces the mechanical signaling system (network broadcasting parameters) with a signal processing system (UE blind estimation). Instead of transmitting interference parameters through control channels, the UE derives them by processing the received RF signals and applying algorithms to estimate the parameters autonomously.
2Measurement precision
If joint blind detection of RI, PMI, and MOD is performed for every RB in every TTI, then interference parameter accuracy is improved, but computational complexity is increased
Solution Approach 1:
The patent segments the blind detection process into distinct stages: first detecting TPR from pilot signals, then using this information to guide subsequent detection of RI, PMI, and MOD. This segmentation allows the UE to process parameters in a structured manner, reducing the computational burden compared to exhaustive joint detection of all parameters simultaneously for every resource block.
Solution Approach 2:
The UE performs preliminary detection of the TPR parameter before detecting other interference parameters. By first estimating the traffic-to-pilot ratio, the UE establishes a foundation that simplifies subsequent parameter detection, as the TPR information helps constrain the search space for other parameters like RI and PMI.
Data Source
AI summary
Methods and apparatuses are provided for canceling interference at a User Equipment (UE) in a wireless communication system. A signal that includes a desired signal and an interference signal is received from at least one Base Station (BS). A random parameter is generated by projecting a vector of the received signal onto a set of projection vectors. A decision metric is determined using the random parameter. A Traffic to Pilot Ratio (TPR) that minimizes the decision metric with respect to both a transmission mode candidate group of the interference signal and a TPR candidate group of the interference signal is determined. The interference signal is canceled from the received signal using the TPR.