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

Compensation of diagonal isi in ofdm signals

A diagonal and signal technology, applied in the field of compensating diagonal ISI and eliminating inter-symbol interference in OFDM signals, can solve problems such as unresolved diagonal ISI, and achieve significant complexity and capacity savings

Active Publication Date: 2014-06-11
TELEFON AB LM ERICSSON (PUBL)
View PDF9 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] Even though Nyquist pulse shaping filters reduce and / or remove inter-channel and / or inter-block ISI, such filters still do not resolve diagonal ISI

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
  • Compensation of diagonal isi in ofdm signals
  • Compensation of diagonal isi in ofdm signals
  • Compensation of diagonal isi in ofdm signals

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0025] Inter-symbol interference (ISI) in transmitted OFDM symbols generally includes a combination of inter-channel ISI, inter-block ISI, and diagonal ISI. figure 1 An exemplary OFDM symbol 12 in a two-dimensional plane representing frequency and time domains. Each moment of time (t k ) included at different subcarrier frequencies (f j ) block 10 of OFDM symbols 12 transmitted on . Blocks 10 of symbols 12 in the frequency-time plane are arranged vertically at subcarrier frequencies f 0 , f 1 , f 2 , f 3 , ... to show. figure 1 Use arrows to show the time instant t due to 4 corresponding to the subcarrier frequency f 2 Demonstrative coupling between different symbol instances induced by the symbol's ISI. Arrows 1 and 2 show that at the same time (t 4 ) at different subcarrier frequencies (f 1 and f 3 Inter-channel ISI caused by symbols transmitted on ). Arrows 3 and 4 show that at different times (t 3 and t 5 ) at the same subcarrier frequency (f 2 Inter-block ...

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

A method and apparatus for compensating for ISI is described herein. A transmitter and receiver work together to develop pulse shaped OFDM symbols with reduced inter-channel ISI between pulse-shaped OFDM symbols transmitted on different sub-carriers at the same time, and inter-block ISI between pulse-shaped OFDM symbols transmitted on the same sub-carrier at different times. In addition, a pre-compensation element in the transmitter and / or a post-compensation element in the receiver compensate for diagonal ISI occurring between pulse-shaped OFDM symbols transmitted on different sub-carriers at different times.

Description

Background technique [0001] The present invention generally relates to interference cancellation, and more particularly to intersymbol interference cancellation in OFDM signals. [0002] Orthogonal Frequency Division Multiplexing (OFDM) is a digital multicarrier modulation scheme utilizing multiple closely spaced orthogonal subcarrier frequencies. Each subcarrier is modulated with a conventional modulation scheme (eg, quadrature amplitude modulation) at a low symbol rate, maintaining a data rate similar to conventional single-carrier modulation schemes in the same bandwidth. OFDMA allows several users to share the available bandwidth by allocating different subcarriers to different users, thus making users orthogonal to each other. Allocation of subcarriers can be dynamic, for example, assigning a larger number of subcarriers to users with larger amounts of data to transmit. OFDM is deployed or planned for a variety of wireless systems, including IEEE802.16 (WiMAX), some IEE...

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 Patents(China)
IPC IPC(8): H04L25/03
CPCH04L25/03343H04L2025/03414H04L25/03834
Inventor P·W·邓特
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