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This paper presents a new Alleviation Interference Scheme (AIS) for Spectral Amplitude Coding (SAC) - Optical Code Division Multiple Access (OCDMA) coding approaches. The AIS SAC-OCDMA systems is demonstrated by utilizing the Flexible Cross Correlation (FCC) code. The FCC code has advantages, such as flexible cross-correlation property at any given number of users and weights, as well as effectively reduces the impacts of phase induced intensity noise (PIIN) and multiple-access interference (MAI). The results indicated good performance whereas the FCC code offers 100%, 207% and 471% percentage larger number of active users compared to MDW W=4, Hadamard and MFH W=8 codes, respectively. Finally, the FCC code has low receive power Psr = -18 dBm which is expected to be more significant for future SAC-OCDMA coding systems.

In this paper, we propose an alleviation interference scheme (AIS) for spectral amplitude coding (SAC) – optical code division multiple access (OCDMA) coding system approaches. The AIS SAC-OCDMA systems is demonstrated by utilizing the new flexible cross correlation (FCC) code. The FCC code has advantages, such as flexibility in-phase cross-correlation at any given number of users and weights, as well as effectively reduces the impacts of phase-induced intensity noise (PIIN) and has the multiple-access interference (MAI) cancelation property. The results indicated good performance whereas the FCC (W = 4, K = 150) AIS SAC-OCDMA coding system offers 66%, 172%, 650% and 900% percentage of cardinality enrichments as a contrast to DCS (W = 4, K = 90), MDW (W = 4, K = 55), MFH (W = 4, K = 20) and Hadamard (W = 8, K = 15) codes, respectively. Finally, the FCC AIS SAC-OCDMA coding system has low effective receive power Psr = −21 dBm which is expected to be more significant for future SAC-OCDMA coding systems without requiring any amplification at the receiving plant.

This paper presented a new class of codes for Fiber-To-The-Home (FTTH) network design based on Spectral Amplitude Coding (SAC) - Optical Code Division Multiple Access (OCDMA) coding approaches. The FTTH SAC-OCDMA network is demonstrated by utilizing the Flexible Cross Correlation (FCC) code. The FCC code has an ability to suppress and cancels the effect of Multi Access Interference (MAI). The results indicated good performance whereas the FCC code offers 100%, 287% and 331% percentage larger cardinality compared to MDW W=4, MFH W=8 and Hadamard codes respectively. Finally, the FCC code accommodates low effective receive power Psr = -23dBm which is expected to be more significant for future FTTH network development for future usages.

In this paper, we present, several aspects of unipolar optical code-division multiple access (OCDMA) codes, focusing on the flexible in-phase cross-correlation code algorithm and its potential for future optical networks. We briefly present a new class of code namely Flexible Cross Correlation (FCC) code for Spectral-Amplitude Coding (SAC) OCDMA approaches. The main coding properties are reviewed. The FCC code provides simple tridiagonal matrix constructions compared to the other SAC-OCDMA codes such as MDW, MQC and MFH codes. This code possesses such a various advantages, including the easier code construction, less complexity of encoder/decoder design and flexible in-phase cross-correlation for uncomplicated to implement using Fiber Bragg Gratings (FBGs) for the OCDMA systems.

A new code for Spectral Amplitude Coding - Optical Code Division Multiple Access (SAC-OCDMA) is proposed and is called Flexible Cross-correlation (FCC) code. The FCC code possesses various advantages; including easy code construction using Tridiagonal matrix compared to other SAC-OCDMA codes such as MDW, MQC and MFH, shorter code length and the important properties of this code is the flexible cross-correlation. Our results reveal that FCC code can effectively alleviated Phase Induced Intensity Noise (PIIN) and allows large cardinality and improve the bit error rate performance.

High-permittivity rectangular bismuth titanate (ReBiT) array antennas for WiMAX application have been investigated, fabricated, and measured. The antennas are designed and constructed with a combination of two-, four-, and six-BiT elements in an array form stacked on a microwave substrate. The impedance bandwidth of the ReBiT is 350 MHz, and it is able to operate in the frequency range of 2.20 to 2.55 GHz, which is suitable for the application of a WiMAX 2.30 GHz system. The utilization of a bismuth titanate (BiT) ceramic that covers about 90% of the antenna led to high radiation efficiency, low cost, and the production of small-size antennas.

This paper presents a memory efficient version of set partitioning in hierarchical tree (SPIHT). The proposed coder called Memory Efficient SPIHT (MESH) uses a single re-usable list instead of three continuously growing linked lists as in conventional SPIHT. The list is re-initialized at the beginning of each bit-plane (coding pass) and is exhausted within the same bit-plane. Another feature of the proposed coder is that it uses a single pass for each bit-plane by merging the sorting and refinement passes of the conventional version of SPIHT. The performance of the proposed coder is measured in terms of coding efficiency, and the worst case dynamic memory requirements due to the list entries in each bit-plane. Performance comparison with SPIHT shows that the proposed coder reduces the dynamic memory requirement by about 50―70% compared to the SPIHT while retaining its coding efficiency.

The paper presents a method for the development of a new class of zero cross correlation optical code for Optical Code Division Multiple Access (OCDMA) system using Spectral Amplitude Coding. The proposed code is called Modified Zero Cross Correlation Code (MZCC). The code has minimum length and can be constructed quite simply for any number of users and for any code weights. The code has better spectrum slicing properties and noise performance in term of Bit Error Rate. The Modified Zero Cross Correlation Code will be demonstrated in simulation using OptiSys. 6.0 to observe noise performance which is better as compared to the existing Zero Cross Correlation Code.

We investigated a dielectric resonator ceramic microstrip patch antenna. The antenna was formed using barium strontium titanate (BST), which had a dielectric constant of 15. A new approach, i.e., the use of a high temperature dielectric probe kit, was used to determine the dielectric constant of BST. A computer simulation technology (CST) microwave studio was used to simulate the BST array antennas, taking into consideration the dielectric constant. We also measured the gain of the antennas loaded with two-, four- , and six-element arrays of the BST antenna and found that the gain of a six-element BST array antenna was enhanced by a gain of about 1.6dB over the four-element BST array antenna at 2.3GHz. The impedance bandwidths of these BST array antennas for voltage standing wave ratio (VSWR) < 2 were in the application ranges

This paper presents the construction of large girth Quasi-Cyclic low density parity check (QC-LDPC) codes and a new multicarrier frequency hopping spread spectrum (MCFH-SS) system. The performance of newly obtained codes is evaluated by comparing with Reed Solomon (RS) codes. The computer simulation results show that the two girth-twelve QC-LDPC codes significantly outperform conventional RS codes with a gain of 2.1 dB at

Block Data Transmission Systems (BDTS) are used in high-speed wireless communication systems with time dispersive channel characteristics. In such systems, blocks of data are separated by zeros to mitigate the effect of Inter-Symbol-Interference (ISI) between the blocks. An optimal detection process employs the Maximum Likelihood Block Detection (MLBD) technique on each block individually in the presence of ISI and Gaussian noise based on the Euclidean distance as an objective function. The detection process is computationally expensive therefore Genetic Algorithms have been used to reduce the overall design complexity. In this work, three types of Genetic Algorithms have been incorporated in the detection process i.e. the conventional GA, Micro GA(µGA), and Hybrid µGA to reduce computational load. In particular, a novel training method for Hybrid µGA has been proposed. Simulation results at 10dB channel SNR for the BDTS with Hybrid µGA executes as low as 3,750 number of objective functions evaluation for a block size of 20. The Bit Error Rate (BER) performance of this system is relatively good i.e. around 1dB inferior to the BDTS using the Exhaustive Search method that requires as many as 220 number of objective functions evaluation.

This paper presents a simulation study for code-division multiplex system over time varying channels. The scheme investigated here uses a precoding technique in the transmitter depending on the channel information, so that no need for any signal processing in the receiver rather than testing against a certain threshold. This coding technique minimizes the effect of intersymbol interference (ISI). The data itself is transmitted in the form of blocks of data symbols separated by blocks of no signal. The appropriate length of each data block depends on the channel parameters expected and the allowed complexity. The impulse response is required to be known at the transmitter which is the requirement for all systems that employ coding at the transmitter.

A new class of code called Flexible Cross-Correlation (FCC) for Spectral-Amplitude Coding Optical Code-Division Multiple-Access (SAC-OCDMA) systems has been de-veloped. The FCC code has advantages, such as flexible cross-correlation property at any given number of users and weights, as well as effectively reduces the impact of Phase-Induced Intensity Noise (PIIN) and Multiple-Access Interference (MAI) cancellation property. The results revealed that the FCC code can accommodate 150 users, where FCC code offers 66%, 172%, 650% and 900% improvement as a contrast to 90, 55, 20 and 15 numbers of users for Dynamic Cyclic Shift (DCS), Modified Double Weight (MDW), Modified Frequency Hoping (MFH) and Hadamard codes, respectively, for a permissible Bit Error Rate (BER) of 10−9 •

Image processing, one of the rapidly expanding area of present day science and technology, finds useful applications in many fields such as medicine, space, remote sensing and document processing. In this paper a simple and effective method is proposed to preserve and produce restored copies of old and faded manuscripts. The manuscripts are here treated as images and edge detection technique is used for the purpose of restoration of these images. The method is tested by applying it to some artificially degraded documents and to some actual old manuscripts ivolving Arabic, Persian and Urdu text. Hard copies of the original manuscripts obtained after restoration were found to be much better as compared to the original or their xerox copies.

The microwave industry has shown increasing interest in electronic ceramic material (ECM) due to its advantages, such as light weight, low cost, low loss, and high dielectric strength. In this paper, simple antennas covered by superstrate layers for 2.30 GHz to 2.50 GHz are proposed. The antennas are compact and have the capability of producing high performance in terms of gain, directivity, and radiation efficiency. Bismuth titanate with high dielectric constant of 21, was utilized as the ECM, while the superstrate layers chosen included a split ring resonator and dielectric material. The superstrate layers were designed for some improvement in the performance of directivity, gain, and return loss. The proposed antennas were simulated and fabricated. The results obtained were small antennas that possess high gain and high directivity with 360°, omni-directional signal transmission that resonant types of conventional dipole antenna cannot achieve. The gain of the antenna with the superstrate layer was enhanced by about 1 dBi over the antenna without a superstrate layer at 2.40 GHz.

This paper considers the use of unequal error protection and median filtering for transmission of images over poor wireless channels usually encountered over cellular mobile networks. Hierarchical Quadrature Amplitude Modulation (HQAM) that provides Unequal Error Protection (UEP) to the transmitted image data is used at the transmitter. In HQAM, non-uniform signal constellation is used to provide different degrees of protection to the significant and non-significant bits in the image data at lower channel Signal to Noise Ratio (SNR). Median filter is employed at the receiver to remove the impulsive noise present in the received image. Simulation results show that the use of HQAM and median filtering provides a gain of PSNR over the more conventional Quadrature Amplitude Modulation (QAM).

The paper presents an adaptive pre-coding algorithm suitable for use in wireless synchronous serial data transmission systems where the channel is slowly varying with time. The pre-coding at the transmitter is such that no signal processing is required at the receiver other than testing the received signal against appropriate thresholds. The data itself is transmitted in the form of blocks of data symbols with different lengths depending on the distortion introduced by the channel. Successive blocks of data are separated either by blocks of training signals or blocks of no signal. The performance of the proposed system is compared with system having fixed block lengths. It is shown that for a given bit error rate the proposed adaptive algorithm achieves considerable higher information transmission rate at relatively reduced complexity of the receiver.

Brain machine interfaces (BMIs) allow patients suffering from neuromuscular disorders to control the movement of robotic limb or wheelchair under their own guidance. So far only invasive technologies e.g. Electrocorticography (ECoG) or intracranial EEG (iEEG) have been widely acknowledged in the design of BMIs. In this paper Electroencephalography (EEG), a non-invasive technology, has been used. The paper deals with study of the features of EEG signals corresponding to two different movements of human hand, namely flexion and extension. The movements have been detected on the basis of the energy and entropy of the corresponding signals. A total of twelve features have been used. Using different combinations of these features a surprisingly high accuracy of 87% has been obtained. Moreover, the use of only discrete cosine transformation of energy and entropy has yielded even a higher average accuracy of 91.93%. With such results, this wrist movement detection algorithm is successfully implemented on a robotic arm.

Optical Code Division Multiple Access (OCDMA) system are limited by the interference between users as well code length due to the code developments. A detailed of code construction for a OCDMA system with flexible cross correlation is presented to reduce the effect of interference thus optimizing the code length. In this paper, the proposed code called Flexible Cross Correlation (FCC) code. The FCC code can be constructed using a simple tridiagonal matrix compared to other OCDMA codes such as MDW, MQC and MFH, thus the FCC code possesses various advantages including easy code construction and less complexity of encoder/decoder design. As a result, OCDMA system performance significantly improved by using FCC code with flexible cross correlation instead of fixed cross correlation such as MDW, MFH and MQC codes.

In this paper, an improvement of achievable system capacity Avalanche photodiode (APD) performance of spatial/spectral modified double weight (MDW) code for cardinality, bit error rates (BER) and noise interference is analyzed. The results in very good agreement indicate that 61% cardinality improvements compare to 2-D MDW code with PIN. The effective transmitted power (P sr ) for 2-D MDW-APD (M=135, N=3) improves by 8.5dBm at 10−9 error floor. At low gain BER value is mitigated through suppressing PIIN. Apparently, performance of the proposed system improves substantially with APD.

The wavelength-time modified double weight (MDW) optical division multiple access (OCDMA) scheme to reduce multiple access interference (MAI) and compensate bit error rate (BER) and phase-induced intensity noise (PIIN) in incoherent OCDMA systems is proposed. The analysis permits thorough understanding of PIIN, shot and thermal noises effect on 2-Dimensional (2-D) MDW OCDMA system performance. PIIN is the dominant noise factor in the OCDMA time-spreading scheme. The 2-D MDW code shows better tolerance to PIIN in comparison to others with enhanced system performance. We prove by numerical analysis that the PIIN is maximally suppressed by the proposed code through minimizing property of cross-correlation in comparison to the 2-D PDC and 2-D MQC OCDMA code.

This paper presented a code with non-zero in-phase cross- correlation Spectral Amplitude Coding Optical Code Division Multiple Access (OCDMA) system. The proposed code called Modified Non Zero Cross Correlation (MNZCC) code. The MNZCC code can be constructed easily for any given number of users, weights and cross correlation (λmax) using tridiagonal matrix properties. MNZCC code will be demonstrated in simulation using OptiSys.6.0. The results indicated that MNZCC code is truly performed better with the presence of noise. We find that the performance of MNZCC code is better than OCDMA codes such as MDW and MFH. Finally, in term of systems complexity, MNZCC code introduced cost effectiveness due to less number of filter with direct detection scheme.

This paper presented a new class of code called Modified Non-Zero Cross Correlation (MNZCC) Code for Spectral-Amplitude Coding Optical Code Division Multiple Access. The MNZCC code can be constructed easily for any given number of users, weights and cross correlation (λmax) with tridiagonal matrix properties. We find that the performance of MNZCC code is better than OCDMA codes such as MDW and MFH. In term of performance, systems with MNZCC code had shown superior performance, where the Bit Error Rate (BER) of MNZCC code is significantly better than OCDMA codes such as MDW and MFH. Fiber Brag Grating filter has been used for the implementing SAC-OCDMA systems. Finally, in term of systems complexity system with MNZCC code with direct detection scheme introduced cost effectiveness due to less number of filter in decoder as well encoder.

In radar systems the very low side-lobes that can be achieved with amplitude and phase modulated pulse trains make their use particularly attractive in systems requiring a large dynamic range. Moreover, the excellent self-clutter rejection performance is obtained without sacrificing the ability for the separation of close targets (no main lobe widening). The additional expense of encoding and decoding in amplitude and phase may be justified for radars that must cope with land clutter or operate in a dense-target environment. This paper presents a method for generating finite length multi-level sequences of large lengths that have low side-lobe energy in their autocorrelation function. It is shown that energy ratio of multilevel sequences that have low side lobe energy, is improved through the process of clipping. The proposed method generates sequences with low side lobe energy and large energy ratio of any desired length starting from sequences of smaller length.

This paper presented the novel of a new class of code with Non-Zero Cross-Correlation for Spectral-Amplitude Coding in Optical Code Division Multiple Access (OCDMA) systems. A new code namely Modified Non-Zero Cross Correlation Code (MNZCC). MNZCC code can be constructed easily for a given number of users K, weights and for a given cross correlation (λmax). The proposed code was demonstrated in simulation using OptiSys. 6.0 to observe the system performance. The results shown, that, the proposed code has superior performance in term of spectrum efficiency and reducing the effect of MAI and suppressing the effects of PIIN, with better bit error probability. The results are obtained for the MNZCC were compared with others existing optical codes such as DW code.

This paper presented the novel of optical code for Optical Code Division Multiple Access (OCDMA) system using Spectral Amplitude Coding. A new class of code, called Modified Non-Zero Cross Correlation Code (MNZCC). MNZCC code has minimum length, can be constructed easily for a given number of users, weights and any desired cross correlation (λmax). The MNZCC code was observed by OptiSys. 6.0 software. The MNZCC code has shown superior performance in term reducing the effect of MAI, with better bit error probability. The results obtain for the MNZCC were compared with others existing optical codes such as DW code.

The choice of a suitable transmit waveform is an important problem in radar design. This is so because the waveform controls resolution and clutter performance and also bears heavily on the system cost. Theoretical studies which provide the basis for technical advances have not, so far, solved the general signal design problem. The knowledge of the properties of the pulse trains, a class of signals particularly well suited to digital processing is therefore, of increasing practical importance. This paper presents a method for generating finite length sequences that have high energy ratio and low side lobe energy in their autocorrelation function. The multilevel sequences with spike like autocorrelation function are generated iteratively, starting with a sequence that has relatively low side lobes in its autocorrelation function. The method can be used to generate sequences of any desired length. It is shown that energy ratio of polyphase sequences that have low side lobe energy, is improved through the process of clipping. Such sequences then can be effectively used to improve the range and Doppler resolution of radars.

This chapter presents performance of a new technique for constructing Quasi-Cyclic Low-Density Parity-Check (QC-LDPC) encrypted codes based on a row division method. The new QC-LDPC encrypted codes are flexible in terms of large girth, multiple code rates, and large block lengths. In the proposed algorithm, the restructuring of the interconnections is developed by splitting the rows into subrows. This row division reduces the load on the processing node and ultimately reduces the hardware complexity. In this method of encrypted code construction, rows are used to form a distance graph. They are then transformed to a parity-check matrix in order to acquire the desired girth. In this work, matrices are divided into small sub-matrices, which result in improved decoding performance and reduce waiting time of the messages to be updated. Matrix sub-division increases the number of sub-matrices to be managed and memory requirement. Moreover, Prototype architecture of the LDPC codes has been implemented by writing Hardware Description Language (VHDL) code and targeted to a Xilinx Spartan-3E XC3S500E FPGA chip.

A high gain and high directive microstrip patch array antenna formed from dielectric layer stacked on bismuth titanate (BiT) ceramics have been investigated, fabricated, and measured. The antennas are designed and constructed with a combination of two-, four-, and six-BiT elements in an array form application on microwave substrate. For gain and directivity enhancement, a layer of dielectric was stacked on the BiT antenna array. We measured the gain and directivity of BiT array antennas with and without the dielectric layer and found that the gain of BiT array antenna with the dielectric layer was enhanced by about 1.4 dBi of directivity and 1.3 dB of gain over the one without the dielectric layer at 2.3 GHz. The impedance bandwidth of the BiT array antenna both with and without the dielectric layer is about 500 MHz and 350 MHz, respectively, which is suitable for the application of the WiMAX 2.3 GHz system. The utilization of BiT ceramics that covers about 90% of antenna led to high radiation efficiency, and small-size antennas were produced. In order to validate the proposed design, theoretical and measured results are provided and discussed.

In this paper, two types of diversity which are space and time diversity are analyzed. The analyses are conducted base on optimization and characteristics analysis. Some methods for optimize this scheme are studied and analyzed to produce the desired results. The objectives of this project are to improve the cooperative communication for better diversity reception and to investigate the range improvement as the cooperative communication is implemented. Performance enhancement for the system that have diversity is established when the communication error probability is decreased at a high channel signal-to-noise ratio (SNR) compared to any system that have less or no diversity.

A new technique for constructing the Quasi Cyclic Low density Parity Check (QC-LDPC) codes based on splitting rows into sub rows method is proposed. The proposed QC-LDPC code, at BER of 10−6 achieves 0.1dB coding gain over the PEG-LDPC codes. Moreover, in the high E b / N 0 region, the proposed code with girths 16 and 20 respectively, achieve 0.056 dB and 0.27 dB at a BER of 10−5 over the randomly constructed code. Simulation results portray that large girth QC-LDPC codes achieve a 0.1dB coding gain over randomly constructed codes and perform 1.3dB from the Shannon-limit at a BER of −6 with a code rate of 0.89 for block length of 1332.

The paper presents an analysis of the Block Transmission System (BTS) that has recently been proposed for mobile channels. Decision boundaries and decision regions have been obtained for the Block Linear Equalizer and the Optimum Detector for the system. Expressions for the error probability for the two detection processes are obtained and these provide the lower and upper bounds to the performance of the BTS in the presence of additive white Gaussian noise. The performance of the BTS is compared with that of the conventional Linear Equalizer. It is shown that despite of the reduced transmission efficiency the performance of the block linear equalizer is comparable with that of the linear equalizer. Furthermore, the Block Transmission System possesses certain inherent advantages over systems using continuous transmission, which makes it suitable for use in mobile communication systems.

A new design code structure for Spectral Amplitude Coding with zero cross- correlation in Optical Code Division Multiple Access (OCDMA) has been proposed in this paper. The proposed code called Modified Zero Cross Correlation Code (MZCC). MZCC code provides much easier code construction, given any number of users K and weights to have minimum code length. MZCC code will be demonstrated using OptiSys 6.0. The results indicated that MZCC code is truly performs better in term of noise performance compared with existing Optical CDMA codes.