Wireless Communication Stream Determination via Diversity Order

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Solution Overview

Problem

Current wireless communication technologies face challenges in suppressing transmission power increases while maintaining a high signal-to-noise ratio (SNR) and array degree of freedom, particularly in multi-user MIMO environments, due to inter-user interference and the need for complex receiver configurations.

Innovation Solution

A wireless communication device and method that determine the optimal number of transmission streams based on transmission line quality information, using a MAC processing unit to calculate diversity order values and compare them to set limits, thereby adjusting the number of streams to minimize power increase and maximize SNR across multiple terminals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If block diagonalization method is used for MU-MIMO precoding, then inter-user interference is eliminated and receiver configuration is simplified, but transmission beam formation for improving received SNR cannot always be formed due to consumption of array degree of freedom for null steering

Engineering Contradiction:
Improveinter-user interferenceVSAvoidreceived signal-to-noise power ratio
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention changes the parameter of precoding method from block diagonalization to block triangulation. This parameter change allows the system to maintain null steering for inter-user interference elimination while preserving array degree of freedom for transmission beam formation, thereby improving received SNR without sacrificing interference elimination capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces dynamic adjustment of the number of transmission streams based on channel conditions and array degree of freedom availability. The base station dynamically determines the optimal number of streams to balance null steering requirements with beam formation capabilities, adapting to changing environmental conditions

Inventive Principle:
Principle #15Dynamics

2Productivity

If the number of spatially multiplexed streams is increased in MU-MIMO, then frequency utilization efficiency is improved, but inter-user interference between transmission signals to respective users becomes more noticeable

Engineering Contradiction:
Improvefrequency utilization efficiencyVSAvoidinter-user interference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the precoding parameter from block diagonalization to block triangulation, which enables higher spatial multiplexing orders while controlling inter-user interference through more efficient null steering that preserves array degree of freedom

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system employs feedback mechanisms where the base station determines the optimal number of transmission streams based on channel state information and array degree of freedom availability, adjusting the multiplexing order dynamically to balance frequency utilization efficiency with interference management

Inventive Principle:
Principle #23Feedback

3Reliability

If block triangulation method is used instead of block diagonalization, then array degree of freedom is preserved for transmission beam formation and received SNR is improved, but the calculation complexity for determining optimal number of streams increases

Engineering Contradiction:
Improvereceived signal-to-noise power ratioVSAvoidcalculation complexity for stream determination
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention applies partial action by determining the number of transmission streams based on a calculated threshold value rather than optimizing all possible parameters. This reduces calculation complexity while still achieving the benefit of preserved array degree of freedom and improved SNR through block triangulation

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP3393065B1Wireless communication apparatus and number-of-transmission-streams determination method
Publication Date: 2019.11.06 MITSUBISHI ELECTRIC CORP
  • EP3393065B1 patent drawingFigure 1~2
  • EP3393065B1 patent drawingFigure 3
  • EP3393065B1 patent drawingFigure 4

AI summary

Provided is a wireless communication device, which is configured to: execute, for each of a plurality of counterpart wireless communication devices to be targets, first processing for determining a maximum number of assignable transmission streams based on transmission line quality information with respect to each of the plurality of counterpart wireless communication devices; execute, for each of the plurality of counterpart wireless communication devices, second processing for calculating a diversity order value of a single stream or each of a plurality of streams through use of the maximum number of transmission streams obtained by the first processing, and compare the calculated diversity order value of the single stream or each of the plurality of streams and a diversity order lower limit value set in advance to each other, to thereby determine a number of transmission streams; and determine the number of transmission streams obtained by the second processing as a finally-determined number of transmission streams for each of the plurality of counterpart wireless communication devices, and notify the finally-determined number of transmission streams that has been determined.