Inlämning av Examensarbete / Submission of Thesis

Hamid Shahzad; Jaishankar Botchu MEE10:35, pp. 53. ING/School of Engineering, 2010.

The work

Författare / Author: Hamid Shahzad, Jaishankar Botchu,
Titel / Title: Applying OSTBC in Cooperative Cognitive Radio Networks
Abstrakt Abstract:

In this report, we introduce cooperative spectrum sensing using orthogonal space time block coding (OSTBC) in order to achieve cooperative diversity in the cognitive radios (CRs) network. Transmit diversity or gain is achieved by introducing
more than one antenna on the transmitter and receiver side, but in small electronic mobile devices it looks impractical. The signals received from the primary users (PUs) are amplified by the cognitive relays and further forwarded to the cognitive controller where decisions are made on the basis of the information collected from each cognitive relay. The cooperative relaying protocol used here in cognitive relays is based on an amplifying-forward (AF) scheme. Alamouti
scheme in OSTBC has been proposed to achieve better detection performance in CR network. The energy detector performance is analyzed over an independent Rayleigh fading channel. In CR network the secondary user (SU) shares PU's frequency band if it fi nds PU is not in its vicinity. The SU starts using the licensed band and leaves the band as soon as it finds the PU is present or going to use the same band. The detection of the spectrum holes by CRs has to be more agile
and intelligent. The main objective of the CRs network is to use the free holes without causing any interference to the PUs. The energy detection technique is simple and outperforms other sensing techniques in cooperative cognitive radio networks. The energy detector collects information from different users, compares it with a certain prede fined threshold () value and then makes a fi nal decision. Detection and false alarm probabilities are derived and manipulated using OSTBC on PU and SU through AF protocol in cooperative communication. The performance of the system is analyzed with single and multiple relays and with and without direct path between the PUs and SUs. Maximum ratio (MRC) and selection combining (SC) schemes are used in energy detector and the results are compared with and without direct link between PU and SU. The analysis is performed by placing the relay close to the PUs. Our results are processed and validated by computer simulation.

Ämnesord / Subject: Signalbehandling - Signal Processing
Telekommunikation - Telecommunications
Mathematics\Probability and Statistics
Nyckelord / Keywords: Cognitive Radio, Cooperative Communication, OSTBC, Rayleigh Fading, Alamouti STBC, AF Relay, MRC, Energy Detector

Publication info

Dokument id / Document id:
Program:/ Programme Magisterprogram i Elektroteknik / Master of Science in Electrical Engineering
Registreringsdatum / Date of registration: 06/01/2010
Uppsatstyp / Type of thesis: Masterarbete/Master's Thesis (120 credits)


Handledare / Supervisor: Prof. Hans-Jurgen Zepernick and Mr. Trung Q. Duong
Examinator / Examiner:
Organisation / Organisation: Blekinge Institute of Technology
Institution / School: ING/School of Engineering

+46 455 38 50 00

Files & Access

Bifogad uppsats fil(er) / Files attached: ostbc_cognitive_radio_final.pdf (868 kB, öppnas i nytt fönster)