Wireless Terminal Rank Indicator Selection for Edge Coverage

Solution Overview

Problem

Current wireless communication systems require significant processing capacity for Channel State Information (CSI) reporting, particularly in determining the optimal Rank Indicator (RI) for MIMO channels, which can burden terminal processing and reduce battery life, especially in edge areas of base station coverage where path-loss is greatest.

Innovation Solution

A method to automatically select a transmit diversity communications rank indicator when a wireless terminal is in an edge area of base station coverage, reducing the need for exhaustive SINR and spectral efficiency calculations, and switching to multiplexed communications in interior areas, thereby optimizing processing capacity and data throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If exhaustive SINR and spectral efficiency calculations are performed to determine the optimal Rank Indicator, then communication reliability is improved, but terminal processing capacity is burdened and battery life is reduced

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidterminal processing capacity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the coverage area into edge areas and interior areas based on path-loss characteristics. In edge areas, the system uses simplified RI selection (diversity mode only) to reduce processing complexity, while in interior areas, full RI calculations are performed to maximize spectral efficiency. This spatial segmentation allows the system to balance reliability and processing capacity requirements differently across the coverage area.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different RI determination strategies to different spatial locations. In edge areas where path-loss is high, the system locally optimizes for processing capacity by using simplified diversity-mode RI selection. In interior areas where channel conditions are better, the system locally optimizes for spectral efficiency by performing exhaustive RI calculations. This local quality approach allows each region to use the most appropriate method for its specific conditions.

Inventive Principle:

Principle #3Local quality

2Productivity

If exhaustive SINR and spectral efficiency calculations are performed to determine the optimal Rank Indicator, then spectral efficiency is improved, but battery life is reduced

Engineering Contradiction:

Improvespectral efficiencyVSAvoidbattery life

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent segments the coverage area into edge areas and interior areas based on path-loss characteristics. In edge areas, the system uses simplified RI selection (diversity mode only) to reduce processing complexity, while in interior areas, full RI calculations are performed to maximize spectral efficiency. This spatial segmentation allows the system to balance reliability and processing capacity requirements differently across the coverage area.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies partial action by performing exhaustive RI calculations only in interior areas where channel conditions support it, rather than in all areas. In edge areas, the system uses a simplified approach that performs only diversity mode RI selection. This partial application of the computationally intensive method reduces overall energy consumption while maintaining spectral efficiency where it can be achieved.

Inventive Principle:

Principle #16Partial or excessive action

3Measurement precision

If Rank Indicator calculations are performed over the entire band at given periods, then channel information accuracy is improved, but processing overhead is increased

Engineering Contradiction:

Improvechannel information accuracyVSAvoidprocessing overhead

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the RI determination process into two parts: simplified diversity-mode RI selection for edge areas and full RI calculations for interior areas. This segmentation allows the system to maintain channel information accuracy where needed (interior areas) while reducing processing overhead in edge areas where full calculations would be excessively time-consuming.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different RI determination strategies to different spatial locations. In edge areas where path-loss is high, the system locally optimizes for processing capacity by using simplified diversity-mode RI selection. In interior areas where channel conditions are better, the system locally optimizes for spectral efficiency by performing exhaustive RI calculations. This local quality approach allows each region to use the most appropriate method for its specific conditions.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS9124329B2Methods of determining rank information and related communications devices and systems

Publication Date: 2015.09.01 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)

AI summary

A method of operating a wireless terminal communicating with a base station over a wireless channel may include determining whether the wireless terminal is in an edge area or an interior area of coverage of the base station. Responsive to determining that the wireless terminal is in an edge area of coverage of the base station, a transmit diversity communications rank indicator may be selected to select diversity communications over the wireless channel between the wireless terminal and the base station. Related wireless terminals are also discussed.