Channels In Communication Systems Research Articles

Design and performance analysis of manchester coder-based body channel communication using FPGA

In general, the Body Channel Communication (BCC) is used to transmit human physiological signals over vast distances. Also, the Error-correcting codes can detect and rectify faults in long-range data transmission. Data is encoded in a predetermined manner for secure transmission. In this paper, a Manchester encoding-based high throughput architecture is proposed for a body channel communication system with a low-power operation mode. Further, the Manchester encoder is designed for high throughput performance with a low complexity architecture, and an analog front-end processing circuit which includes two stage pre-amplifiers. Also, the transmission rate on the BCC transceiver side is boosted by the maximum Consecutive Identical Digit (CID), which is limited by Manchester codes. The Manchester code format is generated by encoding the sensed data. Additionally, a full gain buffer is used to reduce data loss and hardware overhead. Results demonstrate that the suggested Manchester encoder is implemented in 90 nano meter (nm) technology, and the 10 Megabits per second (Mbps) data rate is obtained with a configurable operating frequency ranging from 1 to 100 Megahertz (MHz).

Implementation of field-programmable Gate array-based clock synchronization in the fiber channel communication system.

A sub-nanosecond clock synchronization scheme based on the field programmable gate array (FPGA) is proposed for the Fiber Channel (FC) communication system in this paper. The counter value of the slave node is synchronized to that of the master node through the embedded IEEE 1588 protocol over the communication link. In order to ensure the counter clocks have the same frequency in both nodes, which is recovered from the FC communication link, the clock phase difference is measured by the digital dual mixer time difference technique and the data recovery technique in the Gigabyte Transceiver, and then it is compensated by the mixed-mode clock manager in FPGAs. The proposed clock synchronization approach is evaluated with an FC communication system that has a serial rate of 12.5 Gbps, and the reported experimental results show that the proposed clock synchronization module can achieve a time difference lower than 1ns.

BLIND IDENTIFIABILITY OF A LINEAR DYNAMIC COMMUNICATION CHANNEL MODEL

The article describes the problem of developing a mathematical model of data transmission channel in communication systems in the case when signals at the channel input channel are unknown at the channel output. Development of mathematical models directly from observed data constitutes an identification problem, and the case under consideration belongs to the blind identification problem. The work consistently examines the concept of linear dynamic system identifiability in state space and shows the connection of this concept with the observability and controllability concepts. A number of statements about identifiability of a linear dynamic system describing communication channel are proved. In particular, it is shown that if the system is identifiable, it is sufficient to use the input-output model for its description, while the input-state-output model is redundant. Further, based on the proven statements, blind identifiability conditions are formulated for the case of a discrete system with one input and multiple outputs, which are imposed on the components of the system’s transfer matrix.

Physical prior inspired ensemble learning enables effective channel estimation of underwater visible light communication.

Deep neural networks have been applied to estimate the optical channel in communication systems. However, the underwater visible light channel is highly complex, making it challenging for a single network to accurately capture all its features. This paper presents a novel approach to underwater visible light channel estimation using a physical prior inspired network based on ensemble learning. A three-subnetwork architecture was developed to estimate the linear distortion from inter-symbol interference (ISI), quadratic distortion from signal-to-signal beat interference (SSBI), and higher-order distortion from the optoelectronic device. The superiority of the Ensemble estimator is demonstrated from both the time and frequency domains. In terms of mean square error performance, the Ensemble estimator outperforms the LMS estimator by 6.8 dB and the single network estimators by 15.4 dB. In terms of spectrum mismatch, the Ensemble estimator has the lowest average channel response error, which is 0.32 dB, compared to 0.81 dB for LMS estimator, 0.97 dB for the Linear estimator, and 0.76 dB for the ReLU estimator. Additionally, the Ensemble estimator was able to learn the V-shaped Vpp-BER curves of the channel, a task not achievable by single network estimators. Therefore, the proposed Ensemble estimator is a valuable tool for underwater visible light channel estimation, with potential applications in post-equalization, pre-equalization, and end-to-end communication.

COMPARING DISPERSION COMPENSATION METHODS FOR 120 GB/S OPTICAL TRANSMISSION: PRE, POST, AND SYMMETRICAL SCHEMES

One of the major factors that limit the performance of an optical fiber communication system isdispersion. In order to get a high transmission range with high data rates, techniques must be in place to compensate for the dispersion caused by fiber nonlinearity. Dispersion Compensating Fiber (DCF) and Fiber Bragg Grating (FBG) are the trending dispersion compensation techniques in optical fiber communication. The use of DCF and FBG as a method of dispersion compensation can notably enhance the overall performance of the system. Broadening is a function of distance as well as the Dispersion parameter (D). The dispersion parameter is given in ps/nm/km and changes from fiber to fiber and also is a function of wavelength. In this paper, we investigate pre-, post-, and symmetrical compensating schemes in three different compensating models: DCF, FBG, and DCF cascaded to FBG. The system performance was evaluated in terms of Q-factor and Bit Error Rate (BER) for one optical channel communication system at 120 Gbps Return to Zero (RZ) signal launched over Single-Mode Fiber (SMF) of 100 km by using OptiSystem 7.0 software.

Underwater Wireless Optical Communication System Channel Modelling With Oceanic Bubbles and Water Constituents Under Different Wind Conditions

Optical wireless data transmission from an autonomous underwater vehicle (AUV) to a sea-surface buoy has become a viable solution to support the increasing needs for many applications in the field of marine technology. Despite having unique characteristics and advantages, underwater wireless optical communication remains a challenging field due to the difficulties associated with the harsh marine environments and severe attenuation caused by the bubbles and particulates. This study aims to evaluate the uplink UWOC system in the presence of particles and bubbles under various wind speeds. To calculate the link distances and signal loss between a transmitter and a receiver of the UWOC system, simulations were performed with the inputs of the water optical properties obtained from the Bay of Bengal and Southern Ocean waters and bubble properties derived from the Hall-Novarini (HN) model. Consequently, the normalized received power were calculated for the different receiver configurations and oceanic conditions without and with bubbles. Our results showed that the received power decreased with the increasing wind speeds and smaller bubble populations. The angular and spatial distributions of the received beam increased for smaller bubble populations under high wind speeds. When compared to the clean bubbles, the received power slightly decreased for the non-absorbing coated bubbles with different film thicknesses (0.01 ∼ 1.0 μm) and increased for the absorbing coated bubbles with higher thicknesses (≥1 μm). These results will significantly help the system designer to develop and optimize an UWOC system under different bubble populations and wind speed conditions.

Electromechanical Coupling and Application of High-Frequency Communication Antenna Channel Capacity

The next-generation communication base station antennas represented by phased array antennas are towards high frequency, high gain, high density, and high pointing accuracy. The influence of mechanical structure factors on communication system channel quality is obviously increasing, and the electromechanical coupling problem is becoming more prominent. To effectively guarantee the realization of 5G/6G communication in complex working environments and accelerate the commercial process of future communication systems, an electromechanical coupling channel capacity model is established in comprehensive consideration of the positional shift, attitude deflection, and temperature change of the communication base station phased array antennas. It can be used to rapidly evaluate the communication index degradation of RF devices within the heating environment. Moreover, a sensitivity model of the electric field strength and array antenna channel capacity to the random position error of each element is constructed. The influence of the random positioning error of each element on the communication indicators is analyzed and compared under different working conditions. The simulation results show that the proposed model can effectively provide a theoretical basis and guiding role for the design and manufacture of high-frequency array base station antennas.

Deep Learning Gated Recurrent Neural Network-Based Channel State Estimator for OFDM Wireless Communication Systems

Using deep learning technologies, the channel estimate for an orthogonal frequency division multiplexing system (OFDM) based on pilots is done in this work. To be more specific, deep learning gated recurrent unit (GRU) neural networks are used to present a new framework for channel estimation. Initially, it is trained offline using generated data sets, and thereafter it is used online to track the channel parameters, after which the data transmitted can be recovered. For the purpose of determining the performance of the proposed estimator, three alternative deep learning optimization techniques are used to test it. It is also compared to other commonly used estimators, such as least squares (LS) and minimum mean square error (MMSE). In addition, the proposed estimator is compared with two existing models. Deep learning GRU neural network-based channel state estimator, which are capable of learning and generalizing rapidly, are shown to outperform the comparable estimators when just a few pilots are available. In addition, there is no need for prior knowledge of channel statistics. So, estimating OFDM communication system channel states using the proposed estimator appears promising.

Additional Condition on CSCG Random Vectors for I/Q Channels: With Application to CIS in NOMA

Circularly-symmetric complex Gaussian (CSCG) random vectors (Rvecs) are often used to model practical in-phase and quadrature (I/Q) channels in communication systems. However, we know that CSCG Rvecs do not completely encompass practical I/Q channels. Thus, in this study, we propose an additional condition for CSCG Rvecs to be valid over I/Q channels, namely, a purely-real complex correlation coefficient (CCC). We then investigate the effects of an invalid CCC on the achievable data rate of non-orthogonal multiple access (NOMA) with correlated information sources. Results revealed that a purely-real CCC constraint should be imposed on CSCG Rvecs, when considering practical I/Q channels.

Hybrid NRZ/RZ line coding scheme based hybrid FSO/FO dual channel communication systems

<p><span id="docs-internal-guid-52ae510c-7fff-0f9d-c23b-ec77d8fd1141" style="font-size: 9pt; font-family: 'Times New Roman'; color: #000000; background-color: transparent; font-weight: 400; font-style: normal; font-variant: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">This </span><span id="docs-internal-guid-22aadf85-7fff-c447-0533-2748148ff46b" style="font-size: 9pt; font-family: 'Times New Roman'; color: #000000; background-color: transparent; font-weight: 400; font-style: normal; font-variant: normal; text-decoration: none; vertical-align: baseline; white-space: pre-wrap;">study simulates the hybrid non return to zero (NRZ)/return to zero (RZ) line coding scheme based hybrid free space optics (FSO)/fiber optics (FO) dual channel communication systems. The max Q factor/Min BER are simulated after APD receiver based both erbium doped fiber amplifiers (EDFAs) and wide band traveling wave semiconductor optical amplifiers (WBTWSOAs) with 50 km fiber channel and 4 km FSO channel. Max SPAL/min noise SPAL, max signal power amplitude/min noise signal power variations with spectral frequency, and the total electrical power are demonstrated and clarified in this proposed study. This work emphasized that the fiber channel is reached up to 100 km reach and FSO channel can be also extended to 4 km reach with 40 Gbps.</span></p>

Studying and Modeling the Performance of the TCM-STBC Systems in the Rayleigh Channel

Multiple-input multiple-output (MIMO) systems will play an important role in future generations of wireless networks. Space-time block code (STBC) and space-time trellis code (STTC) are two techniques that may be used in multi-antenna radio systems. This paper aims, most importantly, to study the performance of STBC systems at different vallues of such parameters as spectral efficiency, matrix codes and constellations. A performance comparison between STBC and STTC schemes is performed. In order to show the efficiency of the system’s ability to communicate with uncoded and coded transmission structures over AWGN and Rayleigh channels, the trellis-coded modulation (TCM) is introduced. The results obtained show that the proposed TCM-STBC system model, using one and two receiving antennas, improves the performance of Rayleigh channel communication systems at 9.5 dB and 11.5 dB for a BER of 10−5

Simultaneous localization and mapping navigation of unmanned ground vehicle based on second-order smooth variable structure filter with improved technique to combat fading for advanced wireless communications

Simultaneous localization and mapping is very essential for autonomous navigation when the mobile robot is navigating in unknown environment without a global positioning system. Various techniques to solve the simultaneous localization and mapping problem have been extensively studied using the combination of low-cost sensors. Most of the work in mobile robotics still consists of finding solutions to problems in data exchange between mobile robot and communication control station, which is a challenging task. In fact, communication systems impose severe constraints in terms of channel capacity and transmission quality, because the transmission channel in communication systems is undergoing at the different physical phenomena like scattering, diffusion and diffraction, which occur interference and multiple path effects in wireless communications, while keeping these effects levels low. This article describes a simultaneous localization and mapping problem based on second-order smooth variable structure filter embedded in mobile robot equipped with a sensor for data wireless collection. The inclusion of the control in environments outside the mobile robot field of view can make the wireless communication simultaneous localization and mapping process much more difficult to find a solution under realistic conditions. In order to solve the simultaneous localization and mapping issue and to mitigate the fading phenomena, which affect the quality of service in advanced wireless communication systems, we use a new approach to combat the fading effect without requiring any statistical knowledge of the propagation channel parameters. Several experiments have been done in real-world applications, and good performances were obtained using a second-order smooth variable structure filter–simultaneous localization and mapping algorithm–based wireless communication.

Live Wire – A Low-Complexity Body Channel Communication System for Landmark Identification

This paper presents a robust simplex Body Channel Communication (BCC) system aimed at providing an interactive infrastructure solution for visually impaired people. Compared to existing BCC solutions, it provides high versatility, wearability and installability in an environment in a low complexity hardware-software solution. It operates with a ground referred–transmitter (TX) and it is based on an asynchronous threshold receiver (RX) architecture. Synchronization, demodulation and packetizing and threshold control are completely software defined and implemented using MicroPython. The RX includes Bluetooth® (BT) radio connectivity and a cell-phone application provides push text-to-speech notifications to a smartphone. The hardware achieves a Packet Error Rate (PER) of <inline-formula><tex-math notation="LaTeX">$\sim$</tex-math></inline-formula> 0.1 at 550 kHz pulse center frequency, Synchronized-On Off Keying (S-OOK) modulation and 1 kbps data rate, for an average current consumption of 44 mA.

Enhancing the spectral efficiency and energy efficiency of underwater channel communication by optimal cooperative spectrum sensing using hybrid optimization

SummaryUnderwater wireless sensor networks (UWSNs) contain quite a lot of components such as vehicles and sensors that are deployed in a specific acoustic area to perform collaborative monitoring and data collection errands. These networks are adopted interactively between diverse nodes and ground‐based stations. Currently, UWSNs face problems and challenges that pertain to limited bandwidth, media access control, high propagation delay, 3D topology, spectrum sensing, resource utilization, routing, and power constraints. This proposal deals with the intelligent spectrum sensing in underwater cognitive sonar communication networks (CSCN). Here, the improved performance of spectrum sensing in underwater communication is attained by optimizing the cooperative spectrum sensing and data transmission. The parameters of system like subchannel allocation and transmission power is optimized by a new hybrid meta‐heuristic algorithm by integrating the concepts of deer hunting optimization algorithm (DHOA) and lion algorithm (LA) termed as lion‐enabled DHOA (L‐DHOA). The main intention of optimizing these parameters is to maximize the spectrum efficiency (SE) and energy efficiency (EE) of the underwater channel communication system. From the analysis, with respect to convergence rate, minimum detection probability, and local sensing time, it is proved that the novel hybrid optimization algorithm keeps a great role in making the trade‐off between the SE and EE in underwater channel modeling.

Cognitive Radio Based System for Best Effort Communications in Sound-based Covert Channel for IoT Environments

Nowadays, the use of nodes with different sensing capabilities is pervasive. This leads to many environments capable of monitoring human activity for security, comfort, and connectivity applications among others. However, this also leads to many opportunities for security breaches in personal mobile devices when they are in such environments. In this work, we focus on a covert channel communication system based on sound waves with cognitive radio capabilities. In such system, the mobile nodes are infected with malware that allows the attacker to obtain information from the devices, sending data using a covert channel (hidden communications) to neighbor sensor nodes used for IoT applications through sound waves imperceptible to human ears. A cognitive radio design is based on allowing such hidden communications to occur when the primary channel is unused (i.e., when the user is not using or handling its device). As such, the primary network is considered to be any activity of the mobile (communication, application or service) and the secondary network is the covert channel communication system. Such a system is studied and mathematically analyzed using Continuous Time Markov Chains in order to obtain the throughput in the covert channel for different system parameters. A main result from this work is that, a careful selection of the activation parameter can lead to a more efficient covert data transfer system, irrespective of the rest of the system parameters.

Triple‐mode bandpass filter

triple‐mode bandpass filter

A fluctuation theory of communications

(1) In this paper, we investigate fluctuation properties of communication configurations by considering an ensemble of measurements in the space of probabilities. In the limit of a large number of symbols, in a message communicated in a noisy channel, we explore statistical properties of fluctuations by analyzing the critical behavior and geometric invariants at a given pair of true and false probabilities as the model parameters. (2) In the light of the system’s global stability, we examine the long-range statistical correlations, whereby discuss the nature of the underlying interacting/noninteracting domains and associated phase transitions under variations of the model probabilities. (3) Finally, we provide possible directions towards the instrumentation technology and engineering designing, their optimal developments and perspective implications of the intrinsic geometric towards the fluctuation theory understanding of joint configurations, entanglement entropy, generalized measurements, quantum channels in communication systems and simultaneous measurements.

Research on transmission performance of multi-input multi-output free space optical communication system channel

Traditional systems are susceptible to noise, atmospheric turbulence and other factors, resulting in large system channel transmission error and outage. Therefore, a new method of analyzing transmission performance of multi-input multi-output free space optical communication system channel with an improved space diversity technology is proposed in this paper in the context of different turbulence environments. In this method, with the Gamma–Gamma distribution model, the atmospheric turbulence process is analyzed and the optical field distribution is transformed into a disturbing function based on multi-scale impact; the differential phase-shift-keyed coherent intensity modulation method is adopted to control the turbulence so that the transmitter and receiver can obtain channel state information; a multi-input multi-output free space optical communication (MIMO-FSO) system is formed by constructing a system model and a multi-input multi-output channel model, and the MIMO-FSO system channel is modulated with the improved maximal ratio combining technology to analyze the transmission performance of MIMO-FSO system channel. Experimental results show that the improved method can reduce bit error rate and outage probability of the free space optical system, which has some advantages over traditional systems.

A Review of Channels of Communication System on Project Delivery

A Review of Channels of Communication System on Project Delivery

SEC-TAED based Error Detection and Correction Technique for Data Transmission Systems

&lt;p&gt;In the OFDM communication system channel encoder and decoder is the part of the architecture. OFDM channel is mostly affected by Additive White Gaussian Noise (AWGN) in which bit flipping of original information leads to fault transmission in the channel. To overcome this problem by using hamming code for error detection and correction. Hamming codes are more attractive and it easy to process the encoding and decoding with low latency. In general the hamming is perfectly detected and corrects the single bit error. In this paper, design of single Error Correction-Triple Adjacent Error Detection (SEC-TAED) codes with bit placement algorithm is presented with less number of parity bits. In the conventional Double Adjacent Error Detection (DAED) and Hamming (13, 8) SEC-TAED are process the codes and detects the error, but it require more parity bits for performing the operation. The higher number of parity bits causes processing delay. To avoid this problem by proposed the Hamming (12, 8) SEC-TAED code, it require only four parity bits to perform the detection process. Bit-reordered format used in the method increases the probability detection of triple adjacent error. It is more suitable for efficient and high speed communication.&lt;/p&gt;