FD MMSE Equalization Weight Updates in Multi-Stage PIC Receivers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Adapting equalization weights in turbo equalization receivers is computationally intensive due to the need to invert large matrices, making it challenging, especially with a large number of receive antennas, and limiting feasibility in digital receivers.
Innovation Solution
Obtain updated MMSE equalization weights using initial weights from initial interference cancellation, eliminating the need to invert a matrix of the size nR by nR at each stage, reducing complexity and computation resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If matrix inversion is performed at each stage to adapt equalization weights, then equalization performance is improved, but computational complexity and resource consumption increase significantly
Solution Approach 1:
The patent performs preliminary action by computing and storing the inverse of the correlation matrix once during initial equalization. This pre-computed inverse matrix is then reused in subsequent interference cancellation stages, eliminating the need to perform expensive matrix inversion at each stage. This resolves the contradiction by maintaining equalization performance through weight adaptation while significantly reducing computational complexity through the one-time preliminary computation.
2Reliability
If the number of receive antennas is increased to improve signal reception, then reception capability is improved, but the size of matrices to be inverted increases, making the system less feasible in digital receivers
Solution Approach 1:
The patent applies preliminary action by pre-computing the inverse correlation matrix during the initial equalization stage and storing it for reuse. This approach allows the system to handle a large number of receive antennas for improved signal reception capability, while avoiding the exponential increase in computational complexity that would occur if matrix inversion was performed at each interference cancellation stage. The pre-computed inverse matrix enables efficient weight adaptation without the burden of repeated large-scale matrix inversions.
Data Source
AI summary
A system and method to more efficiently compute updated Frequency Domain (FD) Minimum Mean Squared Error (MMSE) equalization weights in a multi-stage Parallel Interference Cancellation (PIC) receiver after initial interference cancellation. The updated equalization weights (which are to be used during re-equalization) can be obtained using the old equalization weights already computed for initial interference cancellation. There is no need to invert an nR by nR matrix (where nR is the number of receive antennas) at each stage of the PIC receiver during each iteration of equalization and decoding operations. Rather, the matrix to be inverted to obtain updated equalization weights may be of the dimension n×n (where “n” equals the total number of transmission layers in a transmission scheme used in the wireless network). This significantly reduces complexity of determining updated equalization weights during FD MMSE equalization, thereby saving computational resources in a digital receiver performing such equalization.