Inlämning av Examensarbete / Submission of Thesis

Shabbar Ali Khan 1, pp. 92. TEK/avd. för signalbehandling, 2006.

The work

Författare / Author: Shabbar Ali Khan
shal03@student.bth.se
Titel / Title: A study of closed loop space time block coding techniques for MIMO-OFDM
Abstrakt Abstract:

In this dissertation, the STBC-OFDM technique is therefore investigated in order to improve the bit error rate performance of such wireless communication systems speci¯cally those using multiple transmitter and receiver
antennas.An investigation is undertaken of STBC with two transmit and one receive antennas as proposed by Alamouti together with quasi-orthogonal STBC with four transmit and one receive antennas. The simulated performance shows that both full diversity and full code rate is achieved only in the case of two transmit and one receive antenna, whereas the diversity is decreased in the case of four transmit and one receive antennas due to the presence of
coupling term.
This dissertation also presents a method of minimizing such coupling terms by exploiting a phase feedback method as proposed by Cenk Toker, which forces the coupling terms to zero. Both one phase feedback and two phase
feedback methods are used. The simulated performance shows that the practical performance gain between three bit feedback and the two bit feedback is only 0.43dB, so to use two bit feedback appears appropriate. Only a ¯nite
number of bits is allowed for the feedback, to satisfy the quasi-static assumption on the channel.
Finally, closed loop space time block code-OFDM is also investigated, since OFDM is well known to be suited for high data rate applications in fading
channels, due to its high spectral efficiency. Another advantage of an OFDM system lies in its ability to transfer a frequency-selective fading channel into
multiple °at fading channels on different sub-carriers. The simulation results obtained clearly show that the performance gain between three bit feedback
and the two bit feedback is 0.45 dB, therefore a practical two-bit feedback scheme is feasible.

Populärvetenskaplig beskrivning / Popular science summary: In this dissertation a closed loop STBC for OFDM based broadband wireless access scheme based on phase rotation method is investigated. The phase rotation method minimizes the coupling term, since the coupling term reduces the diversity gain. By using
the quantization method we reduce the feedback overheads significantly while maintaining satisfactory diversity performance.
Ämnesord / Subject: Signalbehandling - Signal Processing
Signalbehandling - Signal Processing
Signalbehandling - Signal Processing
Nyckelord / Keywords: closed loop space time block coding

Publication info

Dokument id / Document id:
Program:/ Programme Magisterprogram Telekommunikation och Signalbehandling/Masters progr. Telecom & Signal Proc.
Registreringsdatum / Date of registration: 01/31/2006
Uppsatstyp / Type of thesis: D-Uppsats/Magister/Master

Context

Handledare / Supervisor: Abbas Mohammed
abbas.mohammed@bth.se
Examinator / Examiner: Abbas Mohammed
Organisation / Organisation: Blekinge Institute of Technology
Institution / School: TEK/avd. för signalbehandling
S-372 25 Ronneby
+46 455 38 50 00
I samarbete med / In co-operation with: Cardiff University
Anmärkningar / Comments:

shabbar ali khan
h.no:11-3-399/B, Sadaath Ground , New Mallepally,
Hyderabad-500001 Andhra Pradesh,
India.
+91-40-23344107

Files & Access

Bifogad uppsats fil(er) / Files attached: shabbarthesis.pdf (539 kB, öppnas i nytt fönster)