Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Rayleigh

Performance Evaluation of Dual Tree Complex Wavelet Packet Modulation (Dt-Cwpm) System Over Multipath Rayleigh Fading Channel

Hikmat N. Abdullah; Majid A. Alwan; Fadhil S. Hasan

Engineering and Technology Journal, 2013, Volume 31, Issue 5, Pages 992-1010

The effectiveness of Dual Tree Complex Wavelet Packet Modulation (DT-CWPM) with DQPSK modulation is investigated for communication over flat and frequency selective Rayleigh fading channel. The simulation results show that the performance of the proposed DT-CWPM system is better than that of Orthogonal Frequency Division Multiplexing (OFDM) and other types of Multicarrier Modulation (Slantlet based OFDM and FRAT-OFDM)for the same environment. The comparison of complementary cumulative distribution function (CCDF) of the peak to average power ratio ( PAPR) between different types of multicarrier modulation is also achieved.

Evaluation of Low Density Parity Check Codes Over Various Channel Types

Mahmood Farhan Mosleh

Engineering and Technology Journal, 2011, Volume 29, Issue 5, Pages 961-971

Low density parity check (LDPC) codes are one of the best error correcting
codes in today’s coding world and are known to approach the Shannon limit. As
with all other channel coding schemes, LDPC codes add redundancy to the
uncoded input data to make it more immune to channel impairments. In this paper,
the impact of low-Density Parity-Check code (LDPC) on the performance of
system under Binary Phase Shift keying (BPSK) over an Additive White Gaussian
Noise (AWGN) and other fading (Raleigh and Rician) channels is investigated.
Obtained results show that LDPC can improve transceiver system for various
channel types. At Bit Error Rate (BER) of 10-4 such code with code rate of ½
reduces the Signal to Noise Ratio (SNR) by range of 6.5 to 9 dB for fading
channels in contrast to uncoded system. By studying modern research it has been
found that turbo code can achieved same manner but LDPC decoder faster than
turbo decoder and can be implemented in parallel.

Effect of the Composite Material of the Car's Bumper on its Fundamental Natural Frequency and Response As A Result of Car Vibration

Ruaa Yaseen Hammoudi

Engineering and Technology Journal, 2010, Volume 28, Issue 23, Pages 6768-6784

Effect of vibration on the car's bumper was studied in this paper.
Composite materials are used in manufacturing the car's bumper. The methods that
used in this investigation are Rayleigh's formula for lumped masses in addition to
super position method and the mixture rule. By using these techniques it can be
found the natural frequencies, mode shapes and deflection for the car's bumper.
Different matrix material (resin), fibers and volume fraction are used in this
investigation. MATLAB program are built in this study. The results of this
program are compared with the results of the ANSYS 11 program. The
comparisons show good agreement.