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

MT-CDMA using spreading codes with interference-free windows

A non-interference, spreading code technology applied in the field of digital transmission, which can solve the problems of high peak-to-average power ratio, loss of user capacity, system frequency offset and nonlinear amplification sensitivity, etc.

Inactive Publication Date: 2005-08-31
KONINK PHILIPS ELECTRONICS NV
View PDF0 Cites 15 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] OFDM technology has various drawbacks: synchronization is difficult to perform, and the system is sensitive to frequency offset and nonlinear amplification, which results in high peak-to-average power ratio (PAPR)
However, this advantage is achieved at the cost of increased inter-carrier interference (ICI), which negates this advantage, and thus the increase in user capacity may be lost

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
  • MT-CDMA using spreading codes with interference-free windows
  • MT-CDMA using spreading codes with interference-free windows
  • MT-CDMA using spreading codes with interference-free windows

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0019] figure 1 One MT-CDMA transmitter is shown. The MT-CDMA scheme is mainly proposed for uplink communication of cellular systems due to its asynchronous structure. The encoder ENCOD encodes the input data symbols S of any user k into coded data symbols Sc. The serial-to-parallel converter S / P converts the input coded data symbols Sc into Nc low-rate parallel sub-streams, each of which modulates the subcarrier f p (p=0,...Nc-1), and are added up to obtain one OFDM symbol. The duration Ts of the input encoded data symbols is increased by a factor Nc to obtain T=Nc*Ts as the OFDM symbol duration at the output of the adder. This OFDM symbol is then spread with the associated waveform C of user k k (t) is expanded and sent.

[0020] figure 2 shows the spectrum of the MT-CDMA signal, including the f 0 , f 1 ,.., f Nc-1 Nc subcarriers of . The subcarrier spacing is 1 / T, so the Nc parallel data substreams satisfy the requirement of orthogonality before expansion. Howev...

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 invention relates to digital transmission. It particularly relates to a method of transmitting data using multi-carrier Code-division Multiple Access (CDMA) for accessing a transmission system. The method comprises a step of modulating the data to be transmitted using Orthogonal Frequency-division Multiplexing (OFDM) for producing OFDM modulated data symbols and a step of spreading the OFDM modulated data symbols with spreading codes including a set of predefined sequences, wherein the sequences are predefined so that they satisfy predetermined auto-correlation and / or cross-correlation criteria within a region around the zero-time offset of the correlation function, defined as an interference Free Window (IFW).

Description

technical field [0001] The present invention generally relates to digital transmission. In particular, the present invention relates to a method of transmitting data using multi-carrier Code Division Multiple Access (CDMA) to access a transmission system and a method of receiving such transmitted data. [0002] The invention also relates to a system, a transmitter and a receiver for implementing the above method. [0003] The invention also relates to a computer program product for implementing such a method. [0004] The invention is especially suitable for the future generation of high data rate mobile communication systems (higher than the third generation). Background technique [0005] Due to the ever-increasing demand for high-speed mobile data communications, partly due to the expectation that multimedia services will surpass voice services in the near future, next-generation cellular wireless systems, also known as 4G systems, face challenges in providing high-capa...

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): H04J1/00H04B1/707H04J13/00H04L5/02
CPCH04L5/026H04B2201/709709H04J13/00H04B1/707H04J11/0023H04L27/2627
Inventor A·布拉亚尔B·于纳尔塞拉克L·劳尔C·莫利埃
Owner KONINK PHILIPS ELECTRONICS NV
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