Adaptive Sectorization Mitigates Null Regions in Cellular Systems

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Solution Overview

Problem

Conventional wireless communication systems using fixed beamformed transmissions result in null regions, leading to reduced network reliability, robustness, and coverage area, as user devices within these regions experience low signal-to-interference and noise ratio (SINR), potentially resulting in data loss and decreased performance.

Innovation Solution

The implementation of a method that includes generating a set of transmit beams for space division multiplexing and multiple-input multiple-output (MIMO) transmission, along with opportunistic beamforming, which involves determining channel information to assign user devices to either narrow beams or a wide beam, ensuring a minimum acceptable performance by using a cyclic delay diversity scheme for the wide beam to cover null regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fixed beamformed transmissions are used, then signal to interference and noise ratio (SINR) is enhanced within beam coverage area, but null regions are created where mobile devices experience extremely low SINR

Engineering Contradiction:

Improvenetwork reliabilityVSAvoidnull region coverage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The sector is divided into multiple beams (first beam, second beam, third beam) with different coverage areas and characteristics. Each beam serves specific geographic regions, and the combination of these segmented beams provides more comprehensive coverage than a single beam, reducing the size and impact of null regions while maintaining high SINR in covered areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different beams are assigned to different geographic regions within the sector based on local coverage requirements. The first beam covers a primary region, the second beam covers a secondary region, and the third beam covers a third region. This local optimization ensures that each area receives appropriate signal strength and coverage quality tailored to its specific needs.

Inventive Principle:

Principle #3Local quality

2Reliability

If narrow beams are used for beamforming, then SINR is improved in covered areas, but coverage area is reduced due to null regions

Engineering Contradiction:

Improvecommunication performanceVSAvoidcoverage area

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

Multiple beams with different coverage characteristics are merged to form a composite transmission scheme. The first beam, second beam, and third beam are combined such that their coverage areas overlap and complement each other, ensuring that the union of all beam coverage areas provides more comprehensive sector coverage than any single beam alone, while maintaining high SINR through selective beam usage.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS9179319B2Adaptive sectorization in cellular systems

Publication Date: 2015.11.03 QUALCOMM INC

AI summary

Apparatuses and methodologies are described that enhance performance in a wireless communication system using beamforming transmissions. According to one aspect, a set of transmit beams are defined that simultaneously provides for space division multiplexing, multiple-input multiple output (MIMO transmission and opportunistic beamforming. The addition of a wide beam guarantees a minimum acceptable performance for all user devices.