Pilot-Based SINR Estimation for MIMO Code-Reuse Interference

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Solution Overview

Problem

Conventional CPICH-based SINR estimation methods are inadequate for MIMO systems, leading to overestimation of data channel quality due to code-reuse interference and precoding effects, resulting in high block error rates and reduced throughput.

Innovation Solution

A combination of parametric and non-parametric approaches for pilot-based SINR estimation in MIMO systems, accounting for precoding and code-reuse interference by estimating noise and signal power using despread pilot symbols and incorporating parametric terms to correct for mismatches between data and pilot channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional CPICH-based SINR estimation is used in MIMO systems, then the estimation process is simple, but the SINR estimate becomes inaccurate due to code-reuse interference and precoding effects

Engineering Contradiction:

Improveestimation process complexityVSAvoidSINR estimation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the interference into two distinct components: code-reuse interference and precoding-induced interference. By separating these interference sources, the method can apply specific correction techniques for each type, improving overall SINR estimation accuracy without requiring complete redesign of the estimation process

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces correction parameters that account for code-reuse interference and precoding effects. These parameters modify the standard CPICH-based SINR estimation formula to compensate for the additional interference sources present in MIMO systems, thereby improving measurement precision while maintaining the original estimation framework

Inventive Principle:

Principle #35Parameter changes

2Productivity

If code-reuse interference is present in multi-stream transmission, then data rate increases, but SINR estimation becomes overly optimistic leading to high block error rates

Engineering Contradiction:

Improvedata rateVSAvoidblock error rate

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary correction for code-reuse interference in the SINR estimation process before link adaptation decisions are made. By anticipating and compensating for the interference that will affect data transmission, the method prevents overly optimistic SINR estimates that would lead to high block error rates, thereby improving reliability while maintaining high data rates

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentEP2460292B1Pilot-based SINR estimation for MIMO systems

Publication Date: 2017.12.13 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

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AI summary

A combination of parametric and non-parametric approaches are disclosed for enabling pilot-based SINR estimation, for MIMO systems. The pilot-based SINR estimation embodiments account for preceding applied during either single-stream or multi-stream data transmission. The pilot-based SINR estimation embodiments also account for code reuse interference which arises during multi-stream data transmission when spreading codes are reused on the data channel. Accordingly, mismatches that exist between the data channel and the pilot channel because of preceding and/or code reuse are inherently accounted for by the pilot-based SINR estimation, embodiments disclosed herein.