Receiver-Side Successive Interference Cancellation Across Multiple Cells
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Solution Overview
Problem
Wireless communication systems face challenges in effectively canceling intra-cell and inter-cell interference, which degrade data throughput and voice capability, especially for mobile stations near the edge of a cell where neighboring cell interference is stronger.
Innovation Solution
A method and system for successive interference cancellation at a receiver, where received chips from multiple cells are iteratively processed to cancel previously estimated interference, allowing for improved estimation of received chips by subtracting out previously canceled signals, enhancing data detection and reducing multi-user interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If mobile stations are located near the edge of serving cell, then coverage area is expanded, but inter-cell interference increases
Solution Approach 1:
The patent converts the harmful inter-cell interference into a useful signal by treating it as another user signal that can be estimated and canceled. The interference from neighboring cells is reconstructed using estimated channel responses and user data, then subtracted from the received signal to improve detection accuracy.
Solution Approach 2:
The patent introduces an intermediary processing stage between signal reception and final detection. A multi-user detector estimates channel responses and user data to reconstruct interference signals, which then serve as an intermediary step to cancel the harmful inter-cell interference before final signal detection.
2Productivity
If interference cancellation is performed, then data throughput is improved, but computational complexity increases
Solution Approach 1:
The patent segments the interference cancellation process into distinct stages: channel response estimation, user data estimation, interference signal reconstruction, and interference subtraction. This segmentation allows for systematic processing and enables parallel computation of different user signals, reducing overall computational burden.
Solution Approach 2:
The patent performs preliminary channel response estimation and user data estimation before the actual interference cancellation. By pre-processing the signals to estimate channel responses and detect user data, the system prepares the necessary information for efficient interference reconstruction and cancellation, reducing the complexity of the main detection stage.
3Measurement precision
If iterative interference cancellation is performed, then measurement precision is improved, but processing time increases
Solution Approach 1:
The patent implements an iterative feedback mechanism where the multi-user detector's output from one iteration is fed back as input for the next iteration. The estimated user data and channel responses from previous iterations are used to improve the accuracy of interference cancellation in subsequent iterations, progressively refining the signal estimation.
Solution Approach 2:
The patent performs interference cancellation for all users in the system, including those in serving and neighboring cells, rather than attempting to cancel only the dominant interference sources. This comprehensive approach ensures that even weak interference signals are addressed, improving overall estimation accuracy without requiring excessive iterations.
Data Source
AI summary
Systems and methods for interference cancellation at a receiver in a wireless communication system are provided. In one aspect, a method for interference cancellation is provided. The method comprises providing total received chips received from a plurality of cells. The method also comprises successively estimating received chips for each of the plurality of cells in a plurality of iterations, wherein each of the plurality of iterations after a first iteration comprises canceling previously estimated received chips for one or more of the plurality of cells from the total received chips, and estimating received chips for one of the plurality of cells using the total received chips with the previously estimated received chips for the one or more of the plurality of cells cancelled out.