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Considering a small-scale fading environment in a dense random wireless network, we investigate the impact of the carrier-sensing threshold on the link performance under the premise of a fixed carrier-sensing range. At first, we assume a close transmitter-receiver distance and model the network nodes as a homogeneous Poisson point process (PPP). Then we present a simple analysis model of the conditional...
Due to the unreliable nature of wireless links, sensor nodes frequently encounter degraded performance or lack of connection. This paper provides a real-time status monitoring and channel error diagnosis method in a wireless sensor network. It uses a poll and echo procedure to efficiently collect some physical layer and link layer statistics from both transmitter side and receiver side. A machine...
This paper focuses on the estimation of target's motion parameters in a moving transmitter/moving receiver forward scatter radar scenario. An extension of the quasicoherent processing initially developed for stationary FSR mode of operation is introduced. This offers an estimation of the target's trajectory in a general case where transmitter and receiver can be moving. Simulated and real data are...
This paper investigates the Gaussian state-dependent Z-interference channel (Z-IC), in which two receivers are corrupted respectively by two correlated states that are noncausally known to transmitters and unknown to receivers. Three interference regimes are studied, and the capacity region or sum capacity boundary is characterized either fully or partially under various channel parameters. The impact...
This paper presents a method of enhancing the aperture size and the effective number of elements of a millimeter wave radar array to make it competitive and complementary as an imaging system for collision avoidance and imaging in adverse environments. We increase aperture size by using a Vernier geometry, with a MIMO overlay to provide adaptive beamforming and multi-target tracking. We reduce the...
In this paper, a high efficient differential chaos shift keying (DCSK) based on frequency division multiplexing (FDM) communication system, namely FDM-HEDCSK is proposed. The scheme has two branches and a serial-parallel converter to achieve four attainable bit rates and improve communication security in comparison to DCSK. In this scheme, the combination of two chaos signals is used as the reference...
In this paper, we discuss some conditions for LPI signals, and propose a system with multiple users requiring these LPI properties using the optimal families of polyphase sequences recently discovered by Park et. al. We discuss and prove the bound on the key space for candidates, and conclude that our system is more secure than those employing encrypted sequences using AES-128 against brute-force...
Multi-Carrier Code Division Multiple Access (MC-CDMA) is a novel approach for advanced wireless communication systems, since it has robustness against multipath fading channels. Due to asyncronous transmission among users Multiple Access Interference (MAI) has huge influence on the performance of MC-CDMA system. For supression of MAI, in this paper we have used MC-CDMA system along with the Orthogonal...
In this paper, we consider a T \times R massive MIMO system with up to R simultaneous links (T>> R>>1) and nonlinear amplifiers in each transmitter branch. The impact of a nonlinear amplification is analytically studied and accurate expressions for the spectral characterization of the transmitted signals, as well as the bit-error-rate (BER) are derived. The accuracy...
Since the near-far problem is expected to be a significant issue in the context of tactical communications, the tolerable amount of adjacent channel interference (ACI) is an important design requirement. We describe a numerical simulator which has been developed in order to evaluate the level of ACI arising in mobile ad hoc networks (MANET) in the VHF band when a large number of nodes and radio networks...
The research is devoted to the reduction of multiple access interference (MAI) in chaos-based asynchronous direct sequence code division multiple access (DS-CDMA) communication systems by use of spreading sequences which are selected from a large set of generated chaotic sequences. For the generation of binary chaotic spreading sequences different 1-dimensional maps are examined. As selection criteria...
This paper presents capacity calculations for different MIMO antenna systems. The capacity calculations are applied for a new proposed channel model entitled the spherical model. The presented MIMO antenna systems are consisted of two configurations. Each configuration has four trapezoidal antennas. Configuration I is designed with and without defected ground slot. Configuration II also is designed...
The paper is aimed at the determination and verification of system parameters, that can be achieved with the utilization of commonly available RTL-SDR software defined receiver in TDOA based system intended for position determination of the small-UAS. The paper describes a way of performing practical experiments, measurement setup and properties of the signal used. Experimental results lead to the...
The M-sequence has property of good self-correlative, it has pseudo random property and it is easy to be generated and copied. It mainly be applied to spread spectrum and encryption. Traditional information synchronize way based m-sequence realize information synchronize of transmitter and receiver by periodicity of spread spectrum code. When transmitter sending information in every rate, there will...
In this work, we study the application of analog Joint Source Channel Coding (JSCC) techniques for the transmission of correlated information over fading Multiple Access Channels (MACs) using multiple receive antennas. We consider the distributed encoding of the user information with two different analog JSCC schemes: module-like mappings and uncoded transmission. We evaluate the performance of these...
In this paper, we utilize the minimum mean squared error (MMSE) prediction to compensate imperfect channel reciprocity in achieving physical-layer confidentiality enhancement, particularly for our recently developed secure OFDM system with dynamic subcarrier coordinate interleaving [1]. In the proposed method, the transmitter first estimates the correlation coefficient between the forward and backward...
The uplink in a cellular network where the base station (BS) and an advanced user equipment (UE) that is not the traditional mobile device is investigated. This is proposed as a method of antenna offloading for the typical UE which suffers from size constraints. The Gram-Schmidt (GS) precoding algorithm is used to design novel precoding solutions when the receiver and transmitter can have a large...
A novel code division multiple access (CDMA) using cyclic shift keying (CSK) signaling, namely CSK-CDMA, has been proposed for multiuser underwater acoustic communication. The proposed method uses the cyclic correlation characteristic of spread spectrum signals and time reversal processing to increase the data rate each user and to reduce the complexity of the receiver. In CSK-CDMA system, multiple...
Time reversal (TR) technique has been announced as a promising solution for future wireless communication owing to its competency to provide lower computational complexity and higher throughput for the communication system. TR can exhibit remarkable performance especially in ultra-wideband (UWB) system. In this letter, we theoretically analysis the performance of a MIMO-OFDM system combined with the...
We propose a linear precoder for the layered space-time block coding system [2] over spatially correlated channels with channel covariance matrix feedback at the transmitter. The precoder is a combination of the well known waterfilling solution and the precoder for spatial multiplexing system that minimizes the probability of decoding error. At the receiver, decoding schemes of group zero-forcing...
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