A novel bit level block cipher based symmetric key cryptographic technique using G.C.D is proposed in this research paper. Entire plain text file is read one character at a time and according to the binary representation of ASCII value of the characters, entire plain text file is divided into n number of 16 bit blocks. Then an agreed-upon symmetric key file is formed by dividing each 16 bit blo...

An absolutely secure, fast, inexpensive, robust, maintenance-free and low-power-consumption communication is proposed. The states of the information bit are represented by two resistance values. The sender and the receiver have such resistors available and they randomly select and connect one of them to the channel at the beginning of each clock period. The thermal noise voltage and current can...

In our software-defined radio project we aim at combining two standards: Bluetooth and HiperLAN/2. The HiperLAN/2 receiver requires the most computation power in comparison with Bluetooth. We choose to use this computational power also for Bluetooth and look for more advanced demodulation algorithms such as a Maximum A posteriori Probability (MAP) receiver. This paper discusses a simplified MAP...

This paper studies the bit-error rate (BER) performance of a fast frequency-hopped (FFH) binary frequency-shift-keying (BFSK) clipper receiver in the presence of multitone jamming (MTJ) and additive white Gaussian noise (AWGN). By using the Taylor-series expansion and the quantization approach, the BER expressions for higher diversity levels can be obtained without much extra computational comp...

An opto-electronic receiver (detector and pre-amplifier) necessary to meet the demands of high capacity deep-space missions is designed for a Mars–Earth optical communication link. The receiver requirements are driven by link performance (data rate, bit-error rate, and margin), delivered power, pulse width, background signal, telescope quality, and atmospheric effects. Meeting these requirement...

transmitting the packets through a laser, optical fibre, photodetector and demodulator. The BER of the DPA-recovered channel is shown in Fig. 3 . The ideal curve has been measured by connecting the clock directly from the transmitter to the receiver, while the DPA BER has been measured with I , 2 and 4bit preamble lengths. Longer preambles have not been considered because of the increased compl...

Recall our main goal in designing digital communication networks: to send information reliably and efficiently between nodes. Meeting that goal requires the use of techniques to combat bit errors, which are inevitable in both commmunication channels and storage media (storage may be viewed as “communication across time”; you store something now and usually want to be able to retrieve it later)....

Visible Light Communications (VLC) has been studied thoroughly in recent years as an alternative or complementary technology to radio frequency communications. The reliability of VLC channels highly depends on the availability and alignment of line of sight links. In this work, we study the effect of random receiver orientation for mobile users over VLC downlink channels, which affects the exis...

This paper presents a comparative study of Frequency Hopping Spread Spectrum and Direct Sequence Spread Spectrum techniques. The Transmitter and Receiver have been implemented using MATLAB. Maximum-length sequences, Gold Sequences and Walsh Codes have been used as the pseudorandom codes for transmission. Finally received signal have been evaluated on the basis of Bit Error Rate for all the used...

The error rate link performance has been evaluated and compared for efficient Rake receiver structures in low data rate WBAN (Wireless Body Area Network) channel. Rayleigh and Weibull distributions have been used for generating fading power profiles. This model is based on extensive measurements inside or on the surface of human body. The power profiles for WBAN channel have been generated. The...