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This paper presents physical layer security communication scheme for the wireless wire-tap channel. We investigate the feasibility of using the channel state information (CSI) as the key to encrypt the sending message. The inherent uncertainty and reciprocity of the time-variant wireless channel helps the sender to prevent the eavesdropper from getting any useful information without taking the risk...
Reconciliation protocol is used in quantum key distribution to reverse the error bits. Cascade is the most famous reconciliation protocol. It uses BINARY to correct errors and traces back into history records to find another error. In this paper, we implement the Cascade protocol and carry out some experiments for different BER, where BER is bit error rate for qubits. From the result of experiments,...
Compared with single-carrier DSSS, multi-tone DSSS (MT) obtains larger processing gain with equal spectrum efficiency, but it is more sensitive to imperfect carrier synchronization due to much spectral overlap on non-orthogonal subcarriers. In this paper, the carrier synchronization errors of MT system, including frequency offset and phase noise, were modeled as slowly varying Gaussian random processes...
A low complexity Parallel Interference Cancellation (PIC) technique that is applicable to body area networks (BANs) is presented. Using Direct-Sequence Code Division Multiple Access (DS-CDMA), the technique aims at suppressing interference caused by rapid changes in relative sensors position due to body parts motion as well as interference from adjacent BANs. Interference signal is estimated using...
A low complexity Parallel Interference Cancellation (PIC) technique is proposed to suppress Multi-Access Interference (MAI) and minimize near-far effect for multi-user communication using Direct-Sequence Code Division Multiple Access (DS-CDMA). Interference signal is estimated using a relationship between cyclic correlation of the received signal and user's code of the interferer without requiring...
In this paper, we propose a time-domain receiver design scheme for high data rate single carrier multiple-input, multiple-output (MIMO) underwater acoustic communications. In this scheme, each received packet is artificially partitioned into blocks for processing. The MIMO channel is initially estimated using training blocks at the front of transmitted packets from all transducers. With the estimated...
Spread spectrum communication provides a robust solution for underwater acoustic communication over noisy or otherwise unfavorable channels while allowing multiple users to occupy the same bandwidth at the same time. In this study we compare two variants, differential and noncoherent, of direct sequence code division multiple access (DS-CDMA) side-by-side on their performance over a range of channel...
This paper proposes a print-and-scan (PS) resilient watermarking scheme based on the mean of DCT coefficients (MDC) for a fixed AC frequency of image. We investigate the property of MDC in the PS process and find that the MDC is nearly unchanged after PS, which is approximately zero for natural (non-watermarked) images. The watermark bits are embedded by shifting these PS-invariants to be positive...
A new frequency-domain channel estimation and equalization (FDE) scheme is proposed for single carrier (SC) underwater acoustic communications. The proposed SC-FDE employs a small training signal block for initial channel estimation in the frequency domain and converts the estimated transfer function to a desired DFT (discrete Fourier transform) size for channel equalization of the data blocks. The...
Direct sequence spread spectrum (DSSS) uses a code sequence to spread the symbols at the transmitter and a de-spreader at the receiver to recover the transmitted symbols. The de-spreader via a correlator or a matched filter provides a processing gain (matched filter gain) which enhances the symbol energy over noise thus allowing communications at low input signal-to-noise ratio. This paper analyzes...
In this paper, we propose a spatial multiplexing and diversity joint transmit structure for MIMO-OFDM system where space-frequency block coding (SFBC) is used over all spatial multiplexing layers to obtain both space diversity and frequency diversity gain. We have derived a Monte Carlo probabilistic data association (PDA) detector to get a better bit error rate (BER) performance compared to generic...
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