On the Capacity of Secondary Networks Over Opportunistic Spectrum Access in Rayleigh Fading Channels

Mohammed Abdel-Hafez, Khaled Shuaib, Omkalthoum El-Bashir Hamed

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


In this paper the effect of the opportunistic spectrum access on the spectrum utilization is studied in terms of the secondary network capacity measured at the secondary receiver. A mathematical model is developed to represent the secondary network capacity in Rayleigh fading channel. An exact analytical solution for the capacity is derived for both sensing and accessing fading channels. A numerical evaluation of the channel capacity is presented for different channel sensing and accessing schemes. The effects of detection and accessing channel parameters on the capacity are investigated. The analytical results that are validated by substantial simulations showed how the utilization of the network can be increased significantly by the suggested opportunistic spectrum accessing technique. It was found that when having a good sensing system with a high secondary user signal to noise ratio, accessing the licensed band increases and drives the spectrum utilization to its maximum. In addition, this work shows how the capacity can be positively affected by three factors: the secondary accessing channel, the primary user interference and the desired quality of service (QoS) of primary user. The awareness of a proper sensing scheme can maximize the spectrum utilization without degrading the QoS of primary users.

Original languageEnglish
Pages (from-to)1981-1994
Number of pages14
JournalWireless Personal Communications
Issue number4
Publication statusPublished - Oct 7 2014


  • And information capacity
  • Cognitive radio
  • Opportunistic access
  • Rayleigh fading channel
  • Spectrum sensing
  • Spectrum utilization

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering


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