MUI Cancellation via Phase Matrix in Wireless Systems
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Solution Overview
Problem
Wireless communication systems face limitations in performance and capacity due to multi-user interference, particularly in mobile communication systems where signals from one terminal can interfere with others, necessitating an effective method for interference cancellation.
Innovation Solution
A method and apparatus for canceling multi-user interference in a wireless communication system involve determining the number of tones to accumulate channel values based on a minimum delta cyclic shift and creating a matrix of phase changes to compensate for interference, using a Base Station to cancel interference by considering the phase changes between user equipment signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple terminals are multiplexed in a cell, then system capacity increases, but multi-user interference worsens
Solution Approach 1:
The patent converts the harmful multi-user interference into a beneficial signal by using the interference-carrying pilot signal to estimate channel values. The decorrelator processes these signals to extract useful channel information while canceling the interference, effectively transforming the harmful interference into a source of channel estimation data.
Solution Approach 2:
The patent introduces a decorrelator as an intermediary component that processes the pilot signals from multiple terminals. This intermediary device separates the desired signal from the interference by utilizing the known pilot sequences and minimum delta cyclic shift information, enabling clean channel estimation despite the presence of multi-user interference.
2Reliability
If power control and channel coding are used, then performance restriction is compensated, but system complexity increases
Solution Approach 1:
The patent applies preliminary action by performing channel estimation and interference cancellation in the pilot signal stage before actual data transmission. By determining channel values using the decorrelator on pilot signals with known sequences, the system prepares the channel state information in advance, avoiding the need for complex real-time processing during data transmission.
3Adaptability or versatility
If cyclic shift values are allocated to UEs, then multi-user separation is enabled, but phase variation across tones increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the cyclic shift values allocated to different UEs. This parameter variation creates distinguishable channel responses for each user while maintaining a structured relationship that the decorrelator can exploit. The minimum delta cyclic shift parameter is carefully controlled to balance user separation capability with phase variation management.
Data Source
AI summary
Disclosed is a method for canceling multi-user interference (MUI) by a base station (BS) in a wireless communication system. The method includes determining the number of tones to accumulate channel values among tones included in a resource area, based on a minimum delta cyclic shift (CS) that represents a minimum gap between CS values allocated to user equipments (UEs) and a number of UEs to be multiplexed, creating a matrix of amounts of change in phase for the tones to accumulate for the UEs to be multiplexed, and canceling MUI based on a signal matrix.