Narrowband signal detection in OFDM systems using spectral shaping techniques

Martin Trollip, Khmaies Ouahada, Toshiaki Imoto

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Citation (Scopus)

Abstract

Orthogonal Frequency Division Multiplexing (OFDM) allow data to be transmitted efficiently and reliably by using multiple orthogonal subcarriers. It provides robustness against noise and corruption in the channel. The channel can be either wired or wireless depending on the particular application. Due to the close spacing of subcarriers, OFDM is susceptible to corruption caused by various narrowband signals such as Narrowband Interference (NBI). Spectral shaping shapes the Power Spectral Density (PSD) in order to have certain properties. Spectral shaping might improve the effectiveness of OFDM and make it sustainable in the long run for applications beyond the 4th generation of mobile communications (4G) and Long Term Evolution (LTE). We make use of spectral null codes and load them onto OFDM subcarriers. Introducing narrowband signals in the channel degrades the system's performance and also eliminates the designed spectral properties. From this observation we infer that some narrowband noise is present in the channel. Previously, carriers hit by NBI or other narrowband noise had to be switched off manually. We found that combining OFDM with spectral shaping allows the presence of Narrowband signals in the channel to be detected and conclusions can be drawn over the channel quality. This did not improve the system in terms of bit error rate performance.

Original languageEnglish
Title of host publication2017 IEEE AFRICON
Subtitle of host publicationScience, Technology and Innovation for Africa, AFRICON 2017
EditorsDarryn R. Cornish
PublisherInstitute of Electrical and Electronics Engineers Inc.
Pages232-237
Number of pages6
ISBN (Electronic)9781538627754
DOIs
Publication statusPublished - 3 Nov 2017
EventIEEE AFRICON 2017 - Cape Town, South Africa
Duration: 18 Sept 201720 Sept 2017

Publication series

Name2017 IEEE AFRICON: Science, Technology and Innovation for Africa, AFRICON 2017

Conference

ConferenceIEEE AFRICON 2017
Country/TerritorySouth Africa
CityCape Town
Period18/09/1720/09/17

Keywords

  • NBI
  • OFDM
  • Power spectral density
  • Spectral null codes
  • Spectral shaping
  • Wireless communications

ASJC Scopus subject areas

  • Human-Computer Interaction
  • Signal Processing
  • Computer Vision and Pattern Recognition
  • Artificial Intelligence
  • Computer Networks and Communications
  • Computer Science Applications

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