Engineering and Technology Journal

OFDM has high spectral Performance and pliability in multipath channel effects while MIMO use another strategy for saving power of transmitter by using multi in multi out antennas to make throughput processing in high efficiency. The transceiver MIMO OFDM implemented on an FPGA typeSpartan3 XC3S200 with proper algorithm, Invoke method and QPSK modulation. The project prospective to improve the transceiver operations in terms of data transmission in high speed and saving power for wireless communication system take in consideration the cost of implementation hardware. In the result registered throughput data rate 425 Mbps using spatial algorithm (ICA with SD algorithm) with another advantage reduction in PAR by 6db and BER less than 10-7).The total architecture using 61% slice registers, LUT's of 55% and memory about 67% on board of Spartan-3 XC3S200.

One of the major weakness of Wireless Sensor Networks is the energy consumption because of limited battery resource and battery replacement or recharging difficulty. The research presented in this paper aims to reduce the energy consumption in the physical layer because most the energy consumption occurred in this layer. This reduction will be achieved via the use of ZigBee transceiver standard at the physical layer under 2.4GHz frequency band with the reduced complexity and lower power consumption than other techniques used in Wireless Sensor Network. Furthermore, such use will also enhance energy efficiency, bit error rate, and throughput of the wireless sensor network. In this paper, three different systems have been proposed according to the type of transceiver technique used in wireless sensor network. System1 uses ZigBee transceiver standard over the wireless sensor network without any additional technique whereas system2 uses ZigBee transceiver with Convolutional Coding over the WSNs model. On the other hand, system3 uses the ZigBee transceiver with both diversity techniquesVirtual Multi-Input Multi-Output and with Convolutional Coding over the wireless sensor network model. The simulation of matlab results show that system3 achieves the best energy efficiency performance compared with the other two systems at lower quality of channel. System2 achieves the best energy efficiency performance at medium quality of channel, and system1 achieves better energy efficiency at high quality of channel.

Spatial Multiplexing (SM) can be achieved higher transmission rate without allocating higher bandwidth or increasing transmit power, so it is wildly used recently to serve the extremely demand of mobile communications. But multipath fading is major bottleneck in increasing the data rate and reliability of transfer of information over wireless channel. SM suffers from significant degradation in term of Bit Error Rate (BER) in such environments. In this research it has been tested a SM system with three types of detection. The first results show the Maximum Likelihood (ML) is the better one, but the complexity is increased dramatically with increasing of data rate or the level modulation order in addition of delay time. On the other hand, Zero Forcing (ZF) is very simple related to ML and it suitable for real time communications, but the problem is the Bit Error Rate (BER) is very high related to the performance of ML. So that this research proposed to adopt ZF decoder, and to support its performance, Convolutional Codes (CC) is added to this system to overcome this problem. The results show the proposed scheme gives a gain of about 10 dB of Signal to Noise Ratio (SNR) at BER of 10-4 for code rate of ½ of CC. To reduce the redundancy informations of CC, 2/3 code rate is proposed instead of ½. The results illustrates such system gives significant gain at high SNR, but the problem is the BER in increased up to system with code at low SNR. Also the results confirm that this problem decreases with high number of antennas. So that MIMO system is suitable for high data rate.

This paper presents a proposed blind detection method for Multiple Input Multiple Output-Space Time Coded (MIMO-STC) wireless systems based on Independent Component Analysis (ICA). The proposed method used the statistical independence of the sources of signals for blindly detection of STC signals. The original transmitted signals are estimated by gradient the kurtosis-based objective function of the received signals. In contrast to other approaches, the proposed method does not require any modification in transmission side or using the training sequences. Simulation results using MATLAB demonstrate competitive results for the proposed system comparing with conventional Minimum Mean Squared Error (MMSE) detector. Where at (10-7) Bit Error Rate (BER) there is about (4 dB) and (7.5 dB) improvement in Signal to Noise Ratio (SNR) for the proposed system adopting Orthogonal Space-Time Block Coded (OSTBC) scheme with (6) receiving antennae comparing to the same system with (4) and (2) receiving antennae respectively.

Spatial Multiplexing (SM) over multiple-input multiple output (MIMO) channels significantly improves the data rates over wireless channels. The challenge is to design low complexity and high performance algorithms that capable of accurately detecting the transmitted signals. In this paper, the general model of MIMO communication
system was introduced in addition to several MIMO Spatial Multiplexing (SM) detection techniques. The Bit Error Rate (BER) performance and computational complexity of Minimum Mean Square Error (MMSE), Zero Forcing (ZF), and Maximum Likelihood (ML) detection schemes have been analyzed and compared to each other using Matlab R2009b. Results of simulation illustrates that their performances of MMSE and ZF detectors are close together and need more than 14 dB of Signal to Noise Ratio (SNR) to achieve 10-4 BER. On the other hand ML detector shows better results than MMSE and ZF detectors but the complexity and the delay are
large. Been proposed to install the number of transmitter antennas fixed on 2 and change receiving antennas 2, 3, and 4. Results showed that the present proposal came close to the results of the previous model, but less complexity

Modern wireless communications require wide band width resulting in an
increased demand for Ultra-Wide Bandwidth antennas. This paper proposes a design for a compact, ultra wide bandwidth antenna with metamaterial. It will be small in size and utilize the best performance of spaced array with a good correlation between the antennas. The antennas are designed with metamaterial structures embedded in substrate. Using the size reduction of double the existing type of antennas, the proposed
model exhibits the best in radiation bandwidth, mutual coupling, radiation pattern, return losses, cover UWB frequency range very well in (3.1-10.6)GHz and polarization with a good Isolation of more than 22dB .