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The paper outlines methods that employ the properties of popular FSK (Frequency-shift Keying) modulation for covert transmission of data between two radio transceivers. With the use of dedicated modulation, the risk of interception of confidential information on military radio channels is considerably reduced. The paper also discusses the methods of radio signal modulation in practical applications,...
To increase the attainable data rate of differential chaos shift keying (DCSK), reference-shifted differential chaos shift keying (RS-DCSK) modulation scheme is proposed in this paper. By using both the exact replica and the shifted version of every chaotic reference sample in DCSK as message bearers, two bits of data can be carried in one data-modulated sample sequence., Theoretical analysis and...
This paper proposes low-power design of the Gaussian-Minimum Shift-Keying (GMSK) demodulator using baseband quadrature signals. High-level architecture of this demodulator incorporates CO-ordinate Rotation-DIgital Computer (CORDIC) engine to accept the in-phase and quadrature components from received GMSK signal to generate phase angle and magnitude of the GMSK signal vector at half the sampling frequency...
This work studies the impact of time-synchronization in molecular timing (MT) channels by analyzing three different modulation techniques. The first requires transmitter-receiver synchronization and is based on modulating information on the release timing of information particles. The other two are asynchronous and are based on modulating information on the relative time between two consecutive releases...
In this paper, we propose a comparison method of training symbol (or preamble) and Cyclic Prefix (CP) to improved the frequency synchronization in orthogonal frequency division multiplexing (OFDM). The problems that arise in OFDM system is the time-shift and frequency mismatch between the oscillators in the transmitter and the receiver. It is known as a Carrier Frequency Offset (CFO) problem. By exploring...
Shaped Offset QPSK (SOQPSK) is a highly bandwidth-efficient constant envelope waveform. In order to increase hardware and energy efficiency, a new architecture for fully coherent SOQPSK demodulation is proposed that is suitable for continuous and burst mode transmission. It contains Decision-Directed (DD) synchronization loops for frequency, phase and timing offsets and a low complex method combining...
Wireless sensor networks for aerospace applications need to provide reliable communications with guaranteed real-time functionality in order to serve the requirements of especially the flight control domain. Additionally, the communication system needs to be energy-efficient to enable autonomous operation of wireless sensors. The environment is challenging for wireless communication regarding the...
In this paper, we study the performance of asynchronous and non linear FBMC based multi-cellular networks. The considered system consists of a reference mobile user perfectly synchronized with its reference base station (BS) and K interfering BSs. We have considered both synchronization errors and high power amplifiers (HPA) non linear distortions (NLD). We analyzed first the signal to noise plus...
Because of the wide field of view (FOV) to monitor vessel movements, satellite-based automatic identification system (S-AIS) has been promoted in recent years. However, synchronization is a tough work in S-AIS receiver because of the large Doppler shift and serious signal collision resulting from simultaneous transmission in the FOV of a satellite. In this paper, we propose a pipelined synchronization...
In this paper, cyclic prefix based time synchronization and comb type channel estimation are studied for a SC-FDMA systems with AF relaying cooperative communication technique over time varying channels. Preamble based synchronization and its usage in the block type channel estimation for SC-FDMA systems are vulnerable to time varying channels. Therefore, undeductible channel estimation errors in...
In order to increase throughput and improve system performance for free space optical communications, we consider a pilot-symbol assisted modulation (PSAM) subcarrier phase shift keying (PSK) system with maximum likelihood (ML) phase estimation. Using the phase error probability density function of ML estimation phase error, we study the error rate performance of the subcarrier PSK system with carrier...
Underwater laser communication has been developed in the field of deep-sea exploration, also become a highlight of modern communication technology research. It has the edges of hidden, safe, non-contact and rapid mobility. By now, most data exchange and transmission between underwater sensors and devices are achieved by RS-232 serial ports communication. But it is not able to meet the demands of present...
In this paper, we present a software defined radio-based platform created using LabVIEW and USRP 2920 in order to emulate a distributed antenna system (DAS) setup within an indoor LoS environment. In the proposed test bed, two USRPs are interconnected by MIMO cable and communicate with a single USRP receiver. The two transmitters are used to emulate two spatially separated OFDM transmitters by varying...
In this paper, an novel MMSE MIMO detector is proposed with respect to MMSE MIMO channel estimation. We will show how a two-step MMSE MIMO estimator can be used to facilitate packet detection as well as to provide superior bit error rate performance. This proposed detector takes channel estimation errors into account by the statistical characteristics of MMSE MIMO channel estimation. When compared...
Underwater acoustic communications can be used for several applications. When the underwater link is related to a reservoir, applications can go from water monitoring, both in terms of pollution and physical characteristics, as for example, temperature. Another class of applications can be the remote control of small vehicles/vessels. Due to the limited depth, this kind of underwater acoustic connection...
Recently, Wu and Shu proposed an intriguing technique that transmits data from regular information display devices to smart phone cameras without using any additional hardware or interfering the original content intended to display. This preliminary work reveals the possibility of conducting highspeed data transmission with displays in transparency to human eyes; however, in practice, it could introduce...
Terahertz frequency band of 0.06 - 10 THz is especially interesting for ultra-high-speed wireless communication to achieve data rates of 100 Gbps or higher. To accommodate this demand, advanced terahertz signal processing techniques need to be investigated. Parallel Sequence Spread Spectrum (PSSS) is a physical layer (PHY) baseband technology that seems to be suited for being used for ultra-high speed...
In this paper, we investigate the packet decoding performance degradation due to the joint effects of synchronization and channel estimation errors in orthogonal frequency division multiplexing (OFDM)-based time-division cooperating transmission (TDCT) for the purpose of range extension. The signal to interference and noise ratio (SINR) of maximal ratio combining (MRC) with OFDM TDCT is analyzed in...
In the long term evolution (LTE) uplink systems, reference signals based on Zadoff-Chu sequences are employed for time synchronization and block type channel estimation because the pilots are inserted into all the subcarriers of one single carrier-frequency division multiple access (SC-FDMA) symbol with a certain period. The block-type channel estimation can be adopted for slowly fading channel while...
Sub-GHz gets more attention in the past few years due to unlicensed ubiquitous access in less-interfered frequency band and longer diffraction distance than 2.4 GHz utilized by Zigbee and Wifi. This paper presents the design and implementation of MAC and PHY of a wireless transmission protocol based on Sub-GHz called Micro-Power Wireless Data Transmission Protocol (MPWDTP) with software defined radio...
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