World Applied Sciences Journal 32 (2): 259-266, 2014
ISSN 1818-4952
© IDOSI Publications, 2014
DOI: 10.5829/idosi.wasj.2014.32.02.110
Corresponding Author: Maher Dababneh, Faculty of Engineering, Isra University Amman, Jordan.
E-mail: m.dababneh@iu.edu.jo.
259
Bit Error Rate Performance of Orthogonal Multi-Carrier Code Division
Multiple Access Signal in Frequency Selective Fading Channel
Maher Dababneh and Ibrahim Awad Zamil Qatawneh
1 2
Faculty of Engineering, Isra University Amman, Jordan
1
Faculty of Engineering, Mutah University, AL-Karak, Postal Code : 61710, Jordan
2
Abstract: In this paper a new expression of the signal to noise ratio (SNR) for Group orthogonal Code Division
Multiple access (GO-CDMA) in frequency selective fading is derived and investigated. The SNR performance
for frequency selective fading channel is shown by computer simulation The wireless industry is currently
undergoing a major transition from second generation (2G) to third generation (3G) wireless technologies and
the increasing demands for communication services require higher transmission rates that further stimulates
the demand on wideband technologies depicted in the form of code division multiple access (CDMA) on one
hand. Also, as the privacy is a prime issue in modern communications then the carriers orthogonality is a
fundamental concept for a sustainable development of the communications sector. This paper attempts to
assess wireless communications channels and propose N strategic perspective, an analytical study into the
performance of Group Orthogonal Multi Carrier Code Division Multiple Access (GO-MC-CDMA) in which sub
carriers assigned to users which are orthogonal to other groups, the channel bandwidth is the main theme of
this paper; from which the problems that may affect the communications link are high lighted and measures to
counterbalance and alleviate multi path fading are proposed and investigated. Such measures are: Space
diversity combining techniques and minimum – mean square error and interference cancellation and detection
are considered in this research.
Key words: Fading channel Code Division Multiple Access (CDMA) Multi user interference Additive
White Gaussian Noise Frequency Division Multiple Access
INTRODUCTION operation is in the frequency domain) and other spreads
OFDM is a robust scheme to frequency selective given spreading code and then modulates a different
fading, however, it has several disadvantages such as subcarrier with each of the data stream (the spreading
difficulty in sub carrier synchronization and sensitivity operation in this is in the time domain); similar to a
to frequency offset and nonlinear amplification, which normal direct sequence code division multiple access
result from the fact that it is composed of a number of sub (DS-CDMA) scheme [1]. In order to exploit the maximum
carriers with their overlapping power spectra and exhibits possible channel diversity while being able to
a non-constant nature in its envelope. However, the accommodate dynamic load changes, a group
combination of OFDM signaling and CDMA scheme has orthogonal multi carrier code division multiple access
one major advantage that it can lower the symbol rate in (GO-MC-CDMA) scheme is developed. This scheme does
each subcarrier so that a longer symbol duration makes it not require complex code assignment operations. The set
easier to quasi-synchronize the transmissions. The Multi of subcarriers is partitioned into groups and the users
carrier CDMA schemes are categorized mainly into two who are assigned sub carriers of the same group are
groups: One spreads the original data stream using a separated using spreading codes. Furthermore, it can be
given spreading code and then modulates a different sub seen that grouping the subcarriers together will help the
carrier with each chip (in a sense that the spreading user to achieve full multi path diversity which is essential
the serial-to-parallel (S/P) converted data streams using a