Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Multimodulation transmitter

A transmitter, envelope modulation technology, applied in electrical components, transmission systems, improving amplifiers to reduce nonlinear distortion, etc., can solve problems such as not being particularly effective

Inactive Publication Date: 2005-07-27
TELEFON AB LM ERICSSON (PUBL)
View PDF1 Cites 6 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since such an approach requires two nonlinear amplifiers, it is not a particularly efficient approach for systems that also process constant envelope signals

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Multimodulation transmitter
  • Multimodulation transmitter
  • Multimodulation transmitter

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0033] Signals modulated according to the GMSK modulation scheme can be visualized in the complex signal plane as shown in FIG. 1 . The coordinate system here is assumed to rotate synchronously with the fundamental frequency of the carrier, so only phase differences appear in the diagram. The thus modulated signal is represented by vector 10 . In GMSK, the phase shift is adjusted according to three consecutive bits in the digital input signal. In general, if three consecutive numbers are the same, the phase shifts smoothly by π / 2. This means that the vector 10 moves counterclockwise according to the arrow 11 if the consecutive numbers are the same, and moves clockwise according to the arrow 12 if they are not the same. Vector 10 always maintains its magnitude, ie the end of vector 10 always moves on circle 13 in I-Q space. The modulation scheme described is therefore called a constant envelope scheme. Amplifying constant-envelope signals is relatively easy because non-line...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The present invention discloses a double TRU (Transceiver Unit) ( 45 ). The output signals from the power amplifiers ( 64, 84 ) are combined to one common output signal provided to an antenna arrangement ( 91 ). A DSP (Digital Signal Processor) ( 52, 72 ) of each TRU ( 50, 70 ) comprises means for a constant-envelope modulation scheme ( 54, 74 ) and a non-constant envelope scheme ( 53, 73 ). The DSP:s ( 52, 72 ) select the modulation scheme according to modulation information ( 49, 69 ). In such a way, a switching between different modulation schemes can be performed even on a time-slot basis. For non-constant-envelope modulation, the modulated signal is separated into two component signals. Each TRU ( 50, 70 ) takes care of the amplification of one component. A phase compensation of at least one of the TRU:s ( 50, 70 ) is performed in order to correct for different paths of phases of the power amplifiers ( 64, 84 ). The non-constant envelope modulated signal can also be a multi-carrier signal, e.g. of two or more constant-envelope signals. Also a TCC (Transmitter Coherent Combining) operation is achievable.

Description

technical field [0001] The present invention relates generally to wireless communications, and more particularly to wireless communications transmitter systems. Background technique [0002] In conventional GSM (Global System for Mobile Communications), a modulation scheme following GMSK (Gaussian Minimum Shift Keying) is implemented. GMSK is a constant envelope modulation scheme in which the phase shifts are different according to the bit sequence. GMSK modulation was chosen as a compromise between relatively high spectral efficiency and moderate demodulation complexity. [0003] EDGE (Enhanced Data for Global Evolution) is a high-speed mobile data standard designed to transmit data up to 384kbps for second-generation GSM and TDMA (Time Division Multiple Access) networks. EDGE provides speed enhancements by changing the type of modulation used and making better use of the currently used carrier. It enables high data transmission speeds under good conditions, especially i...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): H04B13/00H04B1/04
CPCH04B1/0483H03F1/32
Inventor A·格兰斯特伦G·约翰松
Owner TELEFON AB LM ERICSSON (PUBL)
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com