Optimization of Spreading Code using Modified Differential Evolution for Wireless Communication

Spread spectrum linked to optimization techniques play a very important role in today’s world. Optimization gives the best one among all the solutions and the spread spectrum is used to minimize distortion, hence optimized spreading code is very important in wireless communication. This study shows a comparison of two recent modified techniques of DE with the help of engineering design problems and application of that modified DE (considering the better one) in wireless communication to optimize logistic map based spreading code. A comparative study of properties of both optimized and non-optimized spreading code is also discussed in this paper. The performance of the optimized spreading code is also evaluated with the help of bit error rate (BER) by applying it in static and dynamic direct sequence spread spectrum system (DSSS). The performance of the proposed technique (optimized dynamic logistic map code based DSSS) displays better results than non-optimized spreading code and orthogonal spreading code considering BER. Therefore, the proposed method can be efficiently applied in the wireless communication system.

CLPDI Algorithm in UWB Synchronization

<div> <div> <div> <p>This paper studies code synchronization in time hopping (TH) ultra wideband (UWB) systems. In TH UWB systems, narrow pulses based on Gaussian pulse are positioned in different locations in consecutive time frames. The location of each frame is defined by a spreading code. The receiver collects the energy of the pulses using the same spreading code. To be able to do that, it has to synchronize itself to the incoming signal. Due to the large bandwidth of the signal, several replicas of the signals arrive into the receiver. Thus, the energy of the signal is spread in time domain causing extra problems to the synchronization procedure. In this paper, earlierly proposed method for direct sequence spread spectrum system is applied for time hopping system. The method is simulated in a multipath environment. The performance measure used is the mean acquisition time. Con- stant false alarm rate criterion is used for the threshold setting rule for comparator. The energies of the multipath components are combined in the acquisition process. Therefore, diversity combining is obtained in the acquisition process, which also leads to performance improvement. </p> </div> </div> </div>

CLPDI Algorithm in UWB Synchronization

<div> <div> <div> <p>This paper studies code synchronization in time hopping (TH) ultra wideband (UWB) systems. In TH UWB systems, narrow pulses based on Gaussian pulse are positioned in different locations in consecutive time frames. The location of each frame is defined by a spreading code. The receiver collects the energy of the pulses using the same spreading code. To be able to do that, it has to synchronize itself to the incoming signal. Due to the large bandwidth of the signal, several replicas of the signals arrive into the receiver. Thus, the energy of the signal is spread in time domain causing extra problems to the synchronization procedure. In this paper, earlierly proposed method for direct sequence spread spectrum system is applied for time hopping system. The method is simulated in a multipath environment. The performance measure used is the mean acquisition time. Con- stant false alarm rate criterion is used for the threshold setting rule for comparator. The energies of the multipath components are combined in the acquisition process. Therefore, diversity combining is obtained in the acquisition process, which also leads to performance improvement. </p> </div> </div> </div>

Binary phase hopping based spreading code authentication technique

Civil receivers of Global Navigation Satellite System (GNSS) are vulnerable to spoofing and jamming attacks due to their signal structures. The Spreading Code Authentication (SCA) technique is one of the GNSS message encryption identity authentication techniques. Its robustness and complexity are in between Navigation Message Authentication (NMA) and Navigation Message Encryption (NME)/Spreading Code Encryption (SCE). A commonly used spreading code authentication technique inserts unpredictable chips into the public spreading code. This method changes the signal structure, degrades the correlation of the spreading code, and causes performance loss. This paper proposes a binary phase hopping based spreading code authentication technique, which can achieve identity authentication without changing the existing signal structure. Analysis shows that this method can reduce the performance loss of the original signal and has good compatibility with the existing receiver architecture.