Multiple Antenna Transmission Under Power Spectral Density Limits

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Solution Overview

Problem

Regulatory restrictions in unlicensed bands limit the maximum radiated power usable in cellular communications, leading to challenges in maintaining power spectral density and compliance with emission requirements, especially when sharing channels among multiple users.

Innovation Solution

Utilizing multiple antennas to transmit signals, ensuring each antenna meets the power spectral density limitations while increasing overall radiated power by distributing the transmission across multiple channels, thereby reducing the need for excessive power back-off.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple antennas are used to transmit signals, then overall radiated power is increased, but power spectral density limitations per antenna must be maintained

Engineering Contradiction:

Improveoverall radiated powerVSAvoidmultiple transmit chains

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The transmission system is segmented into multiple independent transmit chains, each with its own power amplifier and antenna. Each transmit chain operates independently within power spectral density limits, while collectively they achieve higher overall radiated power by distributing the total power across multiple segments.

Inventive Principle:

Principle #1Segmentation

2Reliability

If power is distributed across multiple antennas, then compliance with emission requirements is improved, but power back-off is reduced

Engineering Contradiction:

Improvecompliance with emission requirementsVSAvoidpower back-off

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The solution transitions from a single-dimension power transmission approach to a multi-dimensional approach by distributing power across multiple spatial dimensions (multiple antennas). This allows the system to achieve higher total power while maintaining compliance, effectively adding a spatial dimension to power distribution.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Quantity of substance

If unlicensed bands are used for cellular transmission, then additional bandwidth is provided, but regulatory power limitations are imposed

Engineering Contradiction:

ImprovebandwidthVSAvoidradiated power

Core Design Contradiction:

Quantity of substanceVSPower

Solution Approach 1:

Multiple transmit chains are merged to work in unlicensed bands, combining their individual power outputs to achieve higher overall radiated power while each chain independently complies with regulatory power spectral density limitations. This merging allows utilization of unlicensed bandwidth with enhanced power capability.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12526751B2Multiple antenna transmission to manage radiated power

Publication Date: 2026.01.13 SKYWORKS SOLUTIONS INC

AI summary

Increased radiated power using multiple antennas is disclosed. In certain aspects, power spectral density limitations on a per antenna basis can be met while increasing radiated power for a shared channel by transmitting the signal over multiple antennas. Further aspects relate to allocating a monolithic block of modulation as a single cluster to minimize the required power back-off and maximize power density.