Evaluation of different 4x4 Coded MIMO System

Thuraya Mahmood Qaradaghi1 & Diana Hayder Hussein1

1College of Engineering/ Electrical Engineering Department , Salahaddin University/ Hawler (Arbil), Kurdistan Region – Iraq

In this paper 4x4 coded MIMO-OFDM systems with two different code rate OSTBC
(1/2 and 3/4) and different types of QAM as a baseband modulation have been studied,
and compared with a 4x2 coded MIMO system. The system has been evaluated over a
multipath flat-fading and frequency-selective fading, assuming channels with non line of
sight (NLOS). Three different Doppler frequencies (5, 50 and 100 Hz) have been used to
study the systems in different channel situations. The results shows that increasing the
number of antennas at the receiver side reduce the effect of the Doppler shift, because
increasing the number of antennas means increasing the number of channels, and
transmitting the symbols through these channels in different times. OSTBC with two
different code rate (R=1/2 and 3/4) have been used with 4 transmitting antennas, and
OSTBC with R= 1/2 gives a better results than the one with R= 3/4, because when R=3/4
three symbols are send during 4 time slots, but when R=1/2 just two symbols are send
during four time slots. That is beside sending multi-copies of each symbol in different
time and different space

Key Words:MIMO, OFDM, OSTBC, Rayleigh Channel 

[1] Anurag Sharma, Ankush Kansal, "PAPR ANALYSIS OF 8X8 MIMO OFDM AND OFDM
SYSTEM", International Journal of Advanced Research in Computer and Communication
Engineering, Vol. 2, Issue 8, August (2013).
[2] Muhammad Hassan, Abdul Sattar, "Performance analysis of MIMO-OFDM Systems with focus
on WiMAX", thesis is presented as part of Degree of Master of Science in Electrical
Engineering Blekinge Institute of Technology, Sweden (2010).
[3] Kala Praveen Bagadi, Susmita Das, "MIMO-OFDM Channel Estimation using Pilot Carries",
International Journal of Computer Applications, Volume 2 – No.3, May (2010).

[4] R Veeranna, Sake Pothalaiah, and K Ashok Babu," Implementation of MIMO OFDM STF
Coding Framework for Wireless Communication System", International Journal of Engineering
Science and Technology, Vol. 2 (12), pp.7423-7436. (2010).

[5] Shivendra Singh, Vikas Gupta, and Shiv kumar Yadav, "Performance Analysis of MIMO-
OFDM (802.11n System) for WLAN Channel Model", International Journal of Engineering

Research and Applications (IJERA), Vol. 3, Issue 3, pp.946-949, May-Jun (2013).
[5] Jing Xiao, "ANALYSIS OF OFDM MIMO", A Thesis Presented to the Faculty of San Diego
State University, In Partial Fulfillment of the Requirements for the Degree Master of Sciences
in Electrical Engineering, (2010).
[6] R. Suresh Babu, M. Suganthi, and K. Ramasamy, "BER Performance Comparison of Multiple
Antennas Using Space Time Block Coded OFDM System in Multipath Fading Environment",
ICTACT Journal on Communication Technology, VOL: 02, ISSUE: 01 MARCH (2011).
[7] R.S. Ganesh, J. Jaya Kumari, "A Survey on Channel Estimation Techniques in MIMO-OFDM
Mobile Communication Systems", International Journal of Scientific & Engineering Research,
Volume 4, Issue 5, May (2013).
[8] V. Tarokh, N. Seshadri, and A. R. Calderbank," Space–Time Codes for High Data Rate Wireless
Communication: Performance Criterion and Code Construction", IEEE Transactions on
Information Theory, Vol. 44, No. 2, March (1998).
[9] V. Tarokh, H. Jafarkhani, and A. R. Calderbank, "Space-Time Block Codes from Orthogonal
Design", IEEE Transactions on Information Theory, Vol.45, No.5, July (1999).