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This paper introduces an implementation of a half-duplex decode-and-forward cooperative algorithm using the complete complementary code (CCC) sets. These code sets have an impulsive autocorrelation sum among each set and a cross correlation sum along the set size that vanishes for all shifts. Each user is assigned a set of spreading codes to spread his data and send each of the resulting signals on...
This paper presents a continuous phase modulation (CPM) based single-carrier frequency-domain equalization (CPM-SC-FDE) structure for broadband wireless communication systems. The proposed structure combines the advantages of the frequency diversity and low complexity of SC-FDE and the energy efficiency of CPM. Simulation results show that, the proposed CPM-SC-FDE structure provides a better performance...
In this paper, a neural implementation is suggested for polynomial based image interpolation techniques such as bilinear, bicubic and cubic Spline techniques. The performance of the suggested neural image interpolation algorithm is compared to those of traditional polynomial based image interpolation techniques and to warped distance image interpolation techniques. In this implementation, the modeling...
Many techniques are proposed recently to avoid the performance degradation caused by the channel dispersion using slow frequency hopping (SFH) patterns. Matched frequency hopping (MFH) and clipped matched frequency hopping (CMFH) signals have been proposed as an efficient channel-aware signaling technique in slowly fading dispersive channels. An improved technique is presented in this paper by optimizing...
Continuous phase modulation (CPM) is an attractive scheme for wireless communications because of its constant envelope(CE) and its ability to improve the diversity of the multipath channel. In this paper we propose a new interleaving scheme for the CPM based orthogonal frequency-division multiplexing (CE-OFDM) system, namely chaotic interleaving. The proposed system combines the key characteristics...
Cognitive radio (CR) has become a hotspot in recent research. We can think of a CR as having three main parts: the ability to sense, the capacity to learn, and the capability to adapt. Adaptation to the outside environment to optimize radio parameters has been previously proposed using genetic algorithms (GA) to select the optimal transmission parameters by scoring a subset of parameters and evolving...
Phase modulation based systems have the advantages of constant envelope (CE) signals and the ability to improve the diversity of multipath channels. In this paper, we study the performance of single-carrier (SC) and orthogonal frequency-division multiplexing (OFDM) systems using phase modulation (PM). Both systems are implemented with frequency domain equalization (FDE) to obtain high diversity gains...
The constant modulus array (CMARY) blind beamformer has the main drawback of typically capturing the signal that has the greatest power among the received cochannel signals. Hence, the capture process should be guided by controlling the initial beam steering. The minimum variance distortion less response (MVDR) beamformer is used to estimate the initial beam steering of the CMARY; this combination...
The selective mapping (SLM) scheme is one of the most popular peak-to-average power ratio (PAPR) reduction techniques proposed for multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) systems. One of the major disadvantages of this scheme is the need for the transmission of side information (SI) bits to enable the receiver to recover the transmitted data. The authors present...
In this paper, we present a key exchange protocol for clustered wireless sensor networks based on Elliptic Curve Cryptography, which enables secure key distribution and authentication mechanism. The proposed protocol is optimized for clustered sensor networks and is efficient in terms of complexity, number of message exchange, computation, and storage requirements with optimized security benefits...
Due to the disability of MSINR beamforming receiver to correct for the carrier frequency offset in MC-CDMA uplink systems, we present a new combined MSINR beamforming and MMA algorithm. While MSINR beamforming provides an appropriate beam pattern having its maximum gain along the desired user direction, the suggested MSINR-GCMMARY can capture the desired signal and compensates for carrier frequency...
In this paper, we propose a simple adaptive antenna array based MC-CDMA receiver that combines efficient blind adaptive beamforming based on maximum signal-to-interference-and-noise ratio (MSINR) criterion with the Multimodulus Algorithm (MMA) for a MC-CDMA uplink system. The beamformer is used to enhance the desired signal and reduce the co-channel interference from other directions and compensates...
This paper presents a novel video codec scheme which is suitable for mobile devices and is matched to their limitations. It also takes into consideration the limited computational resources in mobile devices. The coding and decoding take advantage of the wavelet decomposition, the set partitioning in hierarchical trees (SPIHT) and difference frames to substitute the complex motion estimation and compensation...
A new highly secure symmetric stream ciphering technique based on hopping of chaotic maps and orbits is introduced in this paper. The chaotic logistic and quadratic maps are used to generate the cipher, while the tent map is used to generate the map hopping sequence. The key determines the initial conditions, orbits, and orbit hopping patterns. There are eight cipher-generating maps. Each map has...
The need for secret communications is as old as the communication itself [1]. With the rapid growth of the information age accompanied by intensive transfer of multimedia content, data hiding techniques have taken an important role. Its applications have ranged from copyright protection and property assurance to content authentication and steganography. In this paper, a new steganography technique...
The blind beamforming based on the maximum signal-to-(interference plus noise) ratio (MSINR) algorithm can recover a desired user signal among several cochannel users without using a reference signal and without assuming prior knowledge of the array direction characteristics, The main drawback of MSINR algorithm is sensitivity to carrier frequency offsets (CFO). The CFO will cause the continuous phase...
Reliable transmission of high quality images through wireless communication channels represents a great challenge, especially for real-time applications. From one aspect, it is necessary to achieve efficient compression that maintains the good image quality without increasing the transmission bandwidth. Secondly, wireless channels impairments such as fading and interference increase the probability...
This paper studies the use of intelligent (INT) pre-rake combining in direct sequence spread spectrum code-division multiple-access (DS-SS/CDMA) systems. The study considers multipath Rayleigh fading channels in the downlink in single input single output (SISO) and multiple input single output (MISO) environments. The used modulation technique is binary PSK (BPSK) with time division duplexing (TDD)...
Fractal image coding has proved its efficiency as a compression technique for digital images. Recently, using fractal coding for digital image watermarking has gained considerable attention. In this paper, a novel fast image watermarking and data hiding technique is proposed. Watermark embedding is accomplished during region based fractal encoding process which confines the domain pool search space...
An enhanced version of the FBG (Fuzzy Bit Generator), recently introduced by the authors, is presented in this paper. The enhancement is such as to increase the security level of the FBG. The Enhanced- FBG (EFBG) is tested against the NIST statistical test suite as well as the TestUO1 statistical testing package to verify the high level of randomness of the generated output bit stream. In addition,...
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