Fragmented Spectrum RF Transmitter With Alternating Feedback Linearization

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Solution Overview

Problem

Current transmitter systems for radio systems are inefficient in amplifying multiple frequency bands over a wide frequency range, requiring numerous hardware components and suffering from bandwidth limitations in feedback paths, which hinder linearization of RF signals.

Innovation Solution

A transmitter arrangement that generates single-band RF signals with different carrier frequencies, combines them to form a fragmented spectrum signal for wideband amplification, and uses a feedback path to alternately provide feedback for adaptive linearization, allowing efficient parallel amplification and linearization of multiple frequency bands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a full transmitter line-up is provided for each frequency band to support parallel transmission of multiple frequency bands, then the transmitter can support multiple frequency bands, but the energy efficiency decreases and the number of hardware components increases

Engineering Contradiction:
Improvesupport for multiple frequency bandsVSAvoidenergy efficiency
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The transmitter divides the multiple frequency bands into separate frequency paths, with each path handling a specific frequency band. This segmentation allows the system to process different frequency bands independently through a shared amplifier, reducing the need for multiple complete transmitter line-ups and improving energy efficiency while maintaining support for multiple frequency bands.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If a full transmitter line-up is provided for each frequency band to support parallel transmission of multiple frequency bands, then the transmitter can support multiple frequency bands, but the number of hardware components increases

Engineering Contradiction:
Improvesupport for multiple frequency bandsVSAvoidnumber of hardware components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The transmitter merges multiple frequency paths into a single wideband amplifier chain. By combining the frequency paths at an early stage and using a shared amplifier, the system reduces the number of hardware components compared to having separate complete transmitter line-ups for each frequency band, while still maintaining the ability to support multiple frequency bands simultaneously.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a feedback path is used for linearization of the amplified fragmented spectrum RF signal, then the linearization can be performed, but the feedback path acts as a bottleneck with respect to bandwidth, limiting the linearizable signal bandwidth

Engineering Contradiction:
Improvelinearization qualityVSAvoidfeedback path bandwidth limitation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The feedback path is segmented into multiple parallel feedback paths, with each path corresponding to a specific frequency band. This segmentation allows each feedback path to be optimized for its specific frequency range, avoiding the bandwidth bottleneck of a single wideband feedback path while maintaining linearization quality across all frequency bands.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses temporal multiplexing where the feedback path alternates between different frequency bands in periodic intervals. This periodic action allows a single feedback path to handle multiple frequency bands sequentially, effectively increasing the bandwidth capability without requiring a physically wider feedback path, thus maintaining linearization quality while avoiding bandwidth limitations.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2333968B1Transmitter arrangement for fragmented spectrum RF signals
Publication Date: 2012.02.08 ALCATEL LUCENT SA
  • EP2333968B1 patent drawingFigure 1
  • EP2333968B1 patent drawingFigure 2
  • EP2333968B1 patent drawingFigure 3

AI summary

Transmitter arrangement (1) for amplifying a fragmented spectrum RF signal (14) having a plurality of frequency bands (6a, 6b) with different carrier frequencies (f1, f2), comprising: a plurality of frequency paths (P1, P2), each for generating a single-band RF signal (12a, 12b) with a different carrier frequency (f1, f2), a combiner (13) for generating the fragmented spectrum RF signal (14) by combining the plurality of single-band RF signals (12a, 12b), and an amplifier unit (15) adapted for amplification of the fragmented spectrum RF signal (14). A base station (2) and a radio network (3) comprising such a transmitter arrangement (1) as well as a method for signal amplification are also provided. The transmitter arrangement (1) may in particular comprise a feedback path adapted for temporally alternately generating feedback related to the different frequency bands (6a', 6b') of the amplified fragmented spectrum RF signal (14').