Shared Correlation Matrix for Wireless Interference Suppression

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional wireless communication systems face high computational complexity and cost due to the need for individual correlation matrix estimation and inversion for each user in interference suppression, especially in CDMA communications, which worsens with the number of users.

Innovation Solution

The solution involves sharing statistical characteristics of interference among users, using a shared inverse correlation matrix or shared correlation matrix, and modifying channel estimates based on user-specific finger delays to reduce computational complexity, thereby simplifying the process of interference suppression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If individual correlation matrix estimation and inversion is performed for each user, then interference suppression performance is improved, but computational complexity increases

Engineering Contradiction:
Improveinterference suppression performanceVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the correlation matrix estimation process across multiple users by computing a single shared correlation matrix from chip samples of all users instead of estimating separate correlation matrices for each user. This combining approach maintains interference suppression effectiveness while significantly reducing computational complexity, as the shared matrix captures the common interference characteristics experienced by all users in the CDMA system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shared correlation matrix serves as a universal interference model for all users in the system. Rather than requiring user-specific correlation matrices, this single matrix structure provides the necessary interference suppression information for multiple users simultaneously, making the computation universally applicable across different user channels and reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Quantity of substance

If the number of users increases, then system capacity is improved, but computational complexity worsens

Engineering Contradiction:
Improvenumber of usersVSAvoidcomputational complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent combines the correlation matrix computation for all users into a single unified process. By aggregating chip samples from all users and computing one shared correlation matrix, the system avoids the exponential growth in computational complexity that would result from estimating separate matrices for each user, thereby enabling the system to accommodate more users without proportionally increasing computational burden.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentUS7830952B2Reduced complexity interference suppression for wireless communications
Publication Date: 2010.11.09 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • US7830952B2 patent drawing
  • US7830952B2 patent drawing
  • US7830952B2 patent drawing

AI summary

The computational complexity required for interference suppression in the reception of wireless communications from multiple users is reduced by sharing information among the users. In some situations, information indicative of a statistical characteristic of the interference is shared among the users. Delays used to produce the interference statistic information are determined based on rake finger delays employed by the users. In some situations, a parameter estimate that is used to calculate combining weights for the users is shared among the users.