Mixed OCC Length MU-MIMO Scheduling for Interference Reduction

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Solution Overview

Problem

Current multiple-antenna systems in wireless communication, particularly in LTE and 5G standards, face challenges in efficiently managing reference signaling and measurements due to increased power and flexibility requirements, leading to interference and limited MU-MIMO scheduling capabilities.

Innovation Solution

The proposed solution involves configuring user equipment with specific combinations of DMRS ports and OCC lengths for channel estimation, allowing for mixed MU-MIMO scheduling with OCC=2 and OCC=4, enabling co-scheduling of UEs with different channel variation rates and synchronization levels, thereby enhancing MU-MIMO capacity and spectral efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple UEs are co-scheduled in MU-MIMO with same OCC length, then resource utilization improves, but orthogonality is lost and interference increases

Engineering Contradiction:
ImproveMU-MIMO scheduling capacityVSAvoidinterference between UEs
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the OCC length parameter into different values (OCC=2 and OCC=4) to create distinct orthogonal resources. By dividing UEs into groups with different OCC lengths, the system enables simultaneous orthogonal transmission, resolving the contradiction between increasing scheduling capacity and maintaining orthogonality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an additional dimension of differentiation by using mixed OCC lengths (combining time-domain OCC=2 and frequency-domain OCC=4) rather than relying solely on spatial separation. This dimensional expansion allows more UEs to be co-scheduled while preserving orthogonality through multi-dimensional resource separation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If reference signaling is increased for better channel estimation, then measurement precision improves, but system complexity and overhead increase

Engineering Contradiction:
Improvechannel estimation accuracyVSAvoidreference signaling overhead
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes DMRS ports universal by allowing them to serve multiple functions: channel estimation for co-scheduled UEs, interference cancellation reference, and implicit indication of OCC length configuration. This multi-functionality reduces the need for separate reference signals, lowering overhead while maintaining estimation precision.

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

Solution Approach 2:

The patent enables DMRS ports to self-indicate their OCC length configuration through port number assignment, eliminating the need for separate signaling. The system self-organizes the reference signal structure to provide both measurement precision and configuration information without additional overhead.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If fixed OCC length is used for all UEs, then system simplicity is maintained, but adaptability to different channel conditions decreases

Engineering Contradiction:
Improveaccommodation of different channel variation ratesVSAvoidconfiguration management
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent introduces dynamics by allowing the network to flexibly assign different OCC lengths (2 or 4) to different UEs based on their channel conditions, mobility patterns, and scheduling requirements. This dynamic adaptation enables the system to optimize performance for diverse scenarios without requiring complex per-UE configuration management.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by tailoring the OCC length to each UE's specific channel characteristics and position in the time-frequency grid. Instead of a uniform configuration, each UE receives an optimized OCC length suited to its local channel conditions, improving overall system adaptability.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3417564B1MU-MIMO with mixed orthogonal cover code length
Publication Date: 2022.12.21 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3417564B1 patent drawingFigure 1
  • EP3417564B1 patent drawingFigure 2
  • EP3417564B1 patent drawingFigure 3

AI summary

There is disclosed a method for operating a user equipment (10) for a wireless communication network, the method comprising performing, based on a configuration, measurements on received signaling, wherein the configuration indicates a combination length of symbols for the measurements, and wherein performing measurements comprises measuring on a number of symbols indicated by the combination length. The disclosure also pertains to related methods and devices.