Bit Error Rate Level Research Articles

An Optical Differential Method for Underwater Wireless Communication in Turbid Environments

Underwater optical communication has emerged as an essential tool for exploring oceanography and marine resources for underwater vehicles or robots in recent years. Current techniques mostly rely on the paradigm of intensity modulation and direct detection, resorting to more powerful light sources on the transmitting side and more sensitive detectors on the receiving side, thus causing excess energy consumption and system costs. Here, a novel approach, namely, the optical differential communications method (ODCM), is proposed to extend the distance of underwater wireless optical communications in turbid water. The underlying physical reason is explained in theory and demonstrated in experiments. It is found that the stable propagation distance of ODCM could be further extended without relying on intensive light sources, in contrast to conventional methods, showing potential for longer communication ranges. Tests of underwater optical communications are conducted, and the results show that ODCM can significantly reduce the bit error rate (BER) at the same propagation distance or extend the propagation distance for the same BER level of optical signals. As such, this study provides an avenue for long-distance and stable underwater wireless optical communications in turbid environments.

Performance Analysis of BER and SNR Performance in High-QAM Modulations Using Advancements in MIMO Systems

Wireless communications is one of the most active areas of technology development of our time. This development is being driven primarily by the transformation of what has been largely a medium for supporting voice telephony into a medium for supporting other services, such as the transmission of video, images, text, and data. Today, the widely deployed network type is based on a centralized approach that requires a network point of access, commonly called the Access Point (AP), to serves as a gateway between the mobile device and the Internet. The obtained results demonstrate that spatial diversity along with the power of STBC significantly improves the error performance in frequency selective wireless fading channels. The BER level is depend on the modulation type, SNR value and channel behavior. Modulation schemes that we have used in this paper are 4-QAM, 8-QAM, 16-QAM and 64-QAM which further improved using forward error correction codes (FEC). A comparison is made between the diversity gains of MIMO systems in terms of BER for high QAM modulation scheme. This work presents, a simulation toll MATLAB R2023a used for model implemented using Nakagami channel to study the performance analysis of Bit Error rate (BER) V/S Signal to Noise ratio (SNR). Keywords: AWGN, BER, Fading Channel, MIMO System, Nakagami, OFDM, QAM Modulation, SNR, STBC etc.

PERFORMANCE IMPROVEMENT OF TWO-WAY COOPERATIVE DCSK SYSTEM USING GROUPING SUBCARRIER-PERMUTATION INDEX MODULATION

This paper proposes a new two-way half-duplex cooperative communication system based on a new chaotic modulation scheme called Joint Grouping Subcarrier-Permutation Index Modulation-based Differential Chaos Shift Keying (GSPIM-DCSK) in order to enhance its energy efficiency, data rate, and BER-performance. GSPIM-DCSKI utilizes a permutation index to load additional data bits, and the input bits are divided into groups that contain carrier, permutation, and modulated bits. The active and within each group are selected based on carrier index bits. The energy and spectral efficiency of the GSPIM-DCSKI systems are evaluated and compared to GSIM-DCSKI. The performance of the new schemes is evaluated by calculating the bit error rate (BER) under different channel conditions. Finally, the BER performance of the new cooperative system using GSPIM-DCSKI is compared to a traditional cooperative system using DCSK and proves that the new cooperative system has a better performance than the traditional one in different channels. Simulation results show that at the multipath Rayleigh fading channel the proposed cooperative system gained SNR about 3 dB at a BER level of 10^(-3) at than the traditional one and this gain is increased to equal 4 Db when p2=4.

A Channel Compensation Technique Based on Frequency-Hopping Binary Offset Carrier Modulated Signal

Space-Air-GroundIntegrated Network (SAGIN) has been becoming a promising future network construction to enable the integration of terrestrial communications, aerial networks and satellite systems, for achieving high data rate wireless access and seamless coverage. Focusing on the space-to-air propagation, which is requiring transmitted signal of large Doppler shift resilience in dynamic circumstances, the proposed signal as employing I/Q modulation to accommodate frequency-hopping binary offset carrier (FH-BOC) signal and orthogonal frequency division multiplexing (OFDM) signal, and to exploit respective benefits. Finally, numeric results are provided to demonstrate performance superiority on Bit Error Rate (BER) and signal tracking stability. In conclusion, our designed signal requires about 8 dB less energy per bit at the desired BER level than normally compensated OFDM signal.

Sensing Integrated DFT-Spread OFDM Waveform and Deep Learning-Powered Receiver Design for Terahertz Integrated Sensing and Communication Systems

Terahertz (THz) communications are envisioned as a key technology of next-generation wireless systems due to its ultra-broad bandwidth. One step forward, THz integrated sensing and communication (ISAC) system can realize both unprecedented data rates and millimeter-level accurate sensing. However, THz ISAC meets stringent challenges on waveform and receiver design to fully exploit the peculiarities of THz channel and transceivers. In this work, a sensing integrated discrete Fourier transform spread orthogonal frequency division multiplexing (SI-DFT-s-OFDM) system is proposed for THz ISAC, which can provide lower peak-to-average power ratio than OFDM and is adaptive to flexible delay spread of the THz channel. Without compromising communication capabilities, the proposed SI-DFT-s-OFDM realizes millimeter-level range estimation and decimeter-per-second-level velocity estimation accuracy. In addition, the bit error rate (BER) performance is improved by 5 dB gain at the 10°3 BER level compared with OFDM. At the receiver, a deep learning based ISAC receiver with two neural networks is developed to recover transmitted data and estimate target range and velocity, while mitigating the imperfections and non-linearities of THz systems. Extensive simulation results demonstrate that the proposed deep learning methods can realize mutually enhanced performance for communication and sensing, and is robust against Doppler effects, phase noise and multi-target estimation.

MODELING OF IEEE 802.11 COMPUTER NETWORKS OPERATION AT INCREASED INTERFERENCE INTENSITY

Context. High level of industrial noise increases the loss of information frames during transmission, which in turn decreases the network throughput. We propose a mathematical model of IEEE 802.11 networks operation under conditions of increased interference intensity. Objective. The purpose of this paper is to express in an explicit analytical form the effect of bit error rate (BER) on the probability of frame transmission and the network throughput. Method. We have proposed the method for constructing a model that allows you to directly calculate the dependence of the frame transmission probability on the number of stations operating in saturation mode, which is convenient for engineering calculations. The values of the model coefficients were selected by comparing the calculation results with the results obtained using the known Bianchi model, which describes the network operation in the form of a Markov process. In the range of up to 23 stations working with one access point, which corresponds to a collision probability of up to 0.5, the indicated dependences for both models satisfy each other with an accuracy sufficient for the practical application. An expression for the network throughput has been defined. Results. The results of the model development were used to take into account the effect of interference intensity on the information transfer process. This made it possible to explicitly express the effect of BER on the probability of frame transmission and the network throughput in the case of variations in the length of the frames and with a different number of competing stations. The degree of throughput reduction has been determined for BER = 10–5, 5∙10–5, 10–4 and increasing value of minimum contention window. Conclusions. In this work, a mathematical model has been developed for direct calculation of the probability of frame transmission and network throughput at different levels of BER.

Performance evaluation and energy optimization of CM3A cooperative WBAN

This work presents performance evaluation and energy optimization of a cooperative Wireless body area network (WBAN). Link metrics like Bit Error Rate (BER), Signal-to-Noise ratio (SNR), spectral efficiency (SE), and outage probability have been investigated to evaluate the performance of non-cooperative and cooperative WBAN at different frequency bands supporting body-centric communication (Ultra-wideband (UWB), Worldwide Industrial, Scientific and Medical (W-ISM) band, US-ISM (U-ISM) band and Wireless Mobile Telemetry Services (WMTS)). Evaluation reveals that cooperative communication shows better performance by exhibiting improved SNR and SE and lower BER and outage probability compared to non-cooperative communication. A critical comparison of Amplify and forward (A&F) cooperation has been performed with decode and forward (D&F) cooperation. Results reveal that the D&F scheme performs better with increased SNR and SE and lower levels of BER and outage probability in comparison to the A&F scheme by 43.74%, 1.64%, 0.15%, and 99%, respectively. W-MTS with the highest SNR and SE and lowest BER and outage probability outperforms the other frequency bands under both non-cooperative and cooperative scenarios. Further, the threshold distance has been evaluated using the Eigenvalues to optimize the transmission energy for the D&F scenario to enhance the performance of on-body WBAN resulting in an average decrease of 3.8% in the transmitted energy, with UWB showing a maximum reduction of 5.25% thus making the network more energy efficient.

Entirely passive remote node design and system architecture for bus topology based 80Gbps symmetrical NG-PON2

The next generation passive optical network stage 2 (NG-PON2) is a broadcast network in which a large number of optical network units (ONUs) can be served using various network topologies. In this paper, a purely passive remote node (RN) design based on fiber bragg grating (FBG) is presented for the bus topology of a high split NG-PON2 system. The performance of the proposed node has been analysed for a symmetric 80 Gbps NG-PON2 system serving 1024 ONUs in terms of bit error rate (BER) and optical signal to noise ratio (OSNR). The working of the proposed node has been explained with the optical frequency spectrums for downstream and upstream signals. The observed OSNR levels for the ONUs operating at the 1st RN is 84.8743 dB which decreases to 75.7973 dB for the ONUs connected to the 8th RN. The BER level < 10–9 for both upstream and downstream confirms the correct working of the proposed node in the NG-PON2 system.

Frequency-offset-tolerant optical frequency comb-based coherent transmission for intra-datacenter interconnections.

In recent years, in order to increase the capacity and scalability of intra-datacenter (DC) transmission, the optical frequency comb (OFC) source has been considered promising to replace discrete lasers, aiming to reduce the cost of wavelength division multiplexing (WDM) transmission within DC. In this paper, an OFC based coherent architecture is proposed. An OFC, in the receiver side, is split by a splitter with a uniform power ratio and separately used as local oscillators (LOs) to detect the demultiplexed signals. The signal spectrum is copied onto every tone of the LO-OFC, and a large frequency offset (FO) tolerance is achieved. In addition, the required ADC sampling rate is the same as a system without FO. Extensive simulations are conducted. In the simulated coherent WDM transmission system, a 3-tone-OFC is used to provide 3 carriers, and an 11-tone-OFC is split and used to provide LO-OFCs. For a 64GBd polarization multiplexing 16 quadrature amplitude modulation (PM-16QAM) WDM transmission, the tolerances of FO are up to about ±0.3THz and ±0.374THz for the 1st/3rd signal, and the 2nd signal, respectively, below the pre-forward error correction (FEC) bit error rate (BER) level of 1.25×10-2. Moreover, the maximum tolerance of FO linearly increases with the number of effective tones in LO-OFC. Further, extensive experiments with back-to-back connection are conducted to verify the performance. The tolerance of FO is up to >36 GHz for 36GBd PM-16QAM transmission with a 3-tone-LO-OFC below the BER level of 1.25×10-2. The proposed OFC based coherent architecture is a promising solution for intra-DC interconnections with a large FO.

Polarization multiplexing and hybrid modulation based bandwidth efficient NG-PON2 coexisting with GPON and XG-PON

Bandwidth efficiency is an important design parameter for next-generation passive optical network stage 2 (NG-PON2). In this paper, two optical line terminal (OLT) designs based on the polarization split state are proposed for NG-PON2. The first method doubles the data rate per wavelength by separate amplitude modulation of both polarization states, whereas, in the second method, differential phase-shift keying (DPSK) modulates another data stream on each amplitude-modulated state; this approach increases the data rate per wavelength fourfold. The proposed system provides NG-PON2 access while coexisting with a gigabit passive optical network (GPON) and 10 GPON (XG-PON). The proposed system design serves 1024 NG-PON2 opitcal network units (ONUs), 128 GPON ONUs, and 128 XG-PON ONUs. The transmission performance of the system is verified by evaluating the bit error rate (BER) for varied received power. An acceptable BER level of less than ${{1}}{{{0}}^{- 9}}$ is considered in this work.

Investigation of Performance Affecting Parameters on Hybrid Passive Optical Networks

AbstractIn the evolvement of current passive optical networks (PONs), there is ever increasing bandwidth demand due to dynamic service requirements. This introduces challenge for the choice of multiplexing technique and physical layer bounds like fiber length, data rate, and number of users are critical over a suitable architecture. In this article, hybrid wave division multiplexing-time division multiplexing PON is analyzed using variable length of fiber with data rates up to 40 Gbps over a maximum of 128 end users. Comparative study using different frequency spacing’s has shown that it has negligible effect on the Q-factor performance parameter. Further in the work, variable data rates required for different services is successfully transmitted up to 30 km to 128 number of users for an acceptable level of bit error rate.

Experimental Validation of Improved Exponential Companding Technique for SC-FDMA Systems Using WARP Hardware

As single-carrier frequency division multiple access (SC-FDMA) is used in long-term evolution (LTE) uplink communications, high peak-to-average power ratio (PAPR) increases power consumption in mobile devices. It is severe when localized subcarrier mapping is used with higher-order modulations. Companding is an attractive technique that offers a tradeoff between PAPR and bit error rate (BER) performances. This paper proposes an exponential companding technique that uses two companding levels based on a threshold, to reduce PAPR in SC-FDMA systems. It does not increase the average power level of transmitted signal and maintains the BER level without significant degradation from the original system. The proposed scheme has three parameters that can be adjusted for a tradeoff between PAPR, BER, and power spectral density (PSD) performances. Hence it offers more flexibility than the conventional exponential companding scheme. We also present scatter plots to find the optimum threshold value and companding levels. Finally, we verify the proposed technique considering a real-time indoor channel by using a wireless open-access research platform (WARP).

Underwater Image Transmission Using Spatial Modulation Unequal Error Protection for Internet of Underwater Things.

A spatial modulation (SM) scheme has been developed as a hopeful candidate for spectral and energy-efficient wireless communication systems, as it provides a great judgment for the system performance, data transmission rate, receiver complexity, and energy/spectrum efficiency. In SM, the data is conveyed by both habitual M-ary signal constellations and the transmit antennas indices. Therefore, the system data rate improvement due to the side information bits transmitted, encapsulated in indices of the transmit antennas, improves the SM transmission efficiency compared to the different MIMO players. The information bits transmitted over the antenna index and data symbol constellation using M-ary signal performance have different levels of bit error rate (BER) performance. This paper proposes unequal error protection (UEP) scheme for image transmission over the Internet of Underwater Things (IoUTs) using SM. The Set Partitioning in Hierarchical Trees (SPIHT) coders encode the underwater image and classify the encoded bits in two categories: critical and uncritical bits. The critical bits are transmitted over the SM index bits and have a low BER while the uncritical bits are transmitted over high order M-ary signal constellation to resolve the underwater acoustic channel bandwidth limitation problem. The proposed SM-UEP technique has been developed carefully with enough justification and evaluation over the measured underwater acoustic channel and the simulated channel. The simulation results show that the proposed SM-UEP can increase the average peak signal-to-noise ratio (PSNR) of the reconstructed received image considerably, and significantly.

Improving the effectiveness of the multi-frequency signals application under conditions of amplitude limitation

In this paper, simulation modelling of information transmission using spectrally efficient multi-frequency (SEFDM) signals with an amplifier and a limiter on transmission has been held. SEFDM signals have a high peak-to-average power ratio (PAPR). Therefore, we need to limit the value of PAPR to increase the efficiency of the amplifier stages of transceiver devices. An effective value for PAPR limiting has been found. For signal-to-noise ratio 7 dB, level of bit error rate reaches minimum value when the PAPR limit value is within 4.5-5.5 dB. Besides that, a comparison of the effectiveness of detection algorithms with and without feedback has been made. The results showed that detection algorithm with feedback increases the effectiveness of the multi-frequency signals application under conditions of amplitude limitation.

Numerical Conditional Probability Density Function and Its Application in Jitter Analysis

Jitter is a critical factor in the performance of high-speed I/O links. Jitter can be modeled as a discrete-time random process. Both the probability density function (PDF) and the spectral characteristics of jitter are important for evaluating its impact on channel performance. The concept of numerical conditional PDF and a new statistical method called FastBER are proposed in this paper to accurately and efficiently perform bit-error-rate (BER) analysis while taking into account both the PDF and the spectral characteristics of an arbitrary jitter sequence for arbitrarily low BER levels. The proposed method achieves the accuracy and flexibility of a transient approach with the high efficiency of a statistical approach.

CRPUF: A modeling-resistant delay PUF based on cylindrical reconvergence

Physical Unclonable Functions (PUFs) are devices which exploit manufacturing variability to uniquely distinguish individuals, thus preventing cloning for malicious purposes. With the increasing demand for low-cost devices, PUF designs which can effectively combine small silicon area and power consumption with high resistance to attacks have become of great interest. Unfortunately, many delay-based PUFs have revealed security weaknesses, making them less useful in such domains. This paper presents a novel delay-based strong PUF, the CRPUF (Cylindrical Reconvergence PUF). CRPUF is based on a carefully designed cylindrical XOR fabric, which allows for a large number of delay paths, thus producing a large combination of challenge-response pairs (CRPs) with relatively low transistor count. Simulations based on circuit delay variability models were performed to evaluate CRPUF with respect to well-known delay PUFs. The simulation results were then validated against an FPGA prototype to show that the desirable properties of the CRPUF can be obtained in a realistic physical implementation. Experiments show that CRPUF has Hamming Distance, Hamming Weight and Entropy comparable to the best results published so far, with acceptable levels of Bit Error Rate. Moreover, experiments also show that CRPUF is much more resistant to modeling attacks than other delay and some memory-based PUFs, making it a good candidate to systems which have stringent cost and security constraints.

Proposal and performance analysis on the PDM microwave photonic link for the mm-wave signal with hybrid QAM-MPPM-RZ modulation

A polarization division multiplexed (PDM) microwave photonic link for the millimeter (MM)-wave signal with hybrid modulation scheme is proposed in this paper, which is based on the combination of quadrature amplitude modulation, multi-pulse pulse-position modulation and return to zero modulation (QAM-MPPM-RZ). In this scheme, the two orthogonal polarization states enable simultaneous transmission of four data flows, which can provide different services for users according to the data rate requirement. To generate hybrid QAM-MPPM-RZ mm-wave signal, the QAM mm-wave signal is directly modulated by MPPM-RZ signal without using digital signal processing (DSP) devices, which reduces the overhead of the encoding process. Then, the generated QAM-MPPM-RZ mm-wave signal is transmitted in PDM microwave photonic link based on SSB modulation. The sparsity characteristic of QAM-MPPM-RZ not only improves the power efficiency, but also decreases the degradation caused by the fiber chromatic dispersion. The simulation results show that, under the constraint of the same transmitted data rate, the PDM microwave photonic link with 50 GHz QAM-MPPM-RZ mm-wave signal achieves much lower levels of bit-error rate than ordinary 32-QAM. In addition, the increase of laser linewidth brings no additional impact to the proposed scheme.

Transmission of 2.86 Tb/s data stream in silicon subwavelength grating waveguides.

In this paper, we perform an investigation of terabit-scale data transmission in silicon subwavelength grating (SWG) waveguides for wavelength-division multiplexing (WDM) optical signals. Silicon SWG waveguide is capable of decreasing the light confinement in silicon core by engineering the geometry, leading to relatively lower optical nonlinearity compared to silicon wire waveguide. We demonstrate ultrahigh-bandwidth 2.86 Tb/s data transmission through the fabricated 2-mm-long silicon SWG waveguide over a wide range of launch powers. In the experiment, 75 WDM channels are utilized with each carrying 38.12 Gb/s orthogonal frequency-division multiplexing (OFDM) 16-ary quadrature amplitude modulation (16-QAM) signal. With the benefit of efficient reduction on optical nonlinearity, the optimum launch power is increased by 8 dB in SWG waveguide, indicating higher tolerance to the nonlinear impairments, compared to a silicon wire waveguide with identical length. With the optimum launch power, all 75 channels exhibit bit-error rate (BER) values less than 4e-5 after SWG waveguide transmission. We also evaluate the terabit-scale data transmission performance through four silicon SWG waveguides with different lengths (1 mm, 2 mm, 4 mm and 12 mm). The required optical signal-to-noise ratios (OSNRs) to achieve BER level of 1e-3 are around 15.27, 15.47, 16.66 and 20.38 dB, respectively.

Elastic all-optical multi-hop interconnection in data centers with adaptive spectrum allocation

In this paper, a novel flex-grid all-optical interconnect scheme that supports transparent multi-hop connections in data centers is proposed. An inter-rack all-optical multi-hop connection is realized with an optical loop employed at flex-grid wavelength selective switches (WSSs) in an intermediate rack rather than by relaying through optical-electric-optical (O-E-O) conversions. Compared with the conventional O-E-O based approach, the proposed all-optical scheme is able to off-load the traffic at intermediate racks, leading to a reduction of the power consumption and cost. The transmission performance of the proposed flex-grid multi-hop all-optical interconnect scheme with various modulation formats, including both coherently detected and directly detected approaches, are investigated by Monte-Carlo simulations. To enhance the spectrum efficiency (SE), number-of-hop adaptive bandwidth allocation is introduced. Numerical results show that the SE can be improved by up to 33.3% at 40Gbps, and by up to 25% at 100Gbps. The impact of parameters, such as targeted bit error rate (BER) level and insertion loss of components, on the transmission performance of the proposed approach are also explored. The results show that the maximum SE improvement of the adaptive approach over the non-adaptive one is enhanced with the decrease of the targeted BER levels and the component insertion loss.

Adaptive-opportunistic Aloha: A media access control protocol for unmanned aerial vehicle–wireless sensor network systems

Recognizing that data collection in a unmanned aerial vehicle–wireless sensor network system is significantly different from that in a conventional wireless sensor network system, we propose a media access control protocol called adaptive-opportunistic Aloha for unmanned aerial vehicle–wireless sensor network systems. Based on a cross-layered design, this proposed adaptive-opportunistic Aloha protocol takes several important factors into consideration, including distribution of sensors, energy consumption, and transmission efficiency. In order for unmanned aerial vehicle to uniformly collect data from the ground sensors that are distributed in a random fashion, adaptive-opportunistic Aloha adopts a priority-based mechanism for channel assignment and collision avoidance, and importantly, the priority could be adaptively changed according to locations and distribution of the sensors. To improve energy efficiency, the adaptive-opportunistic Aloha can effectively put the sensors into the sleep mode when they do not need to send data, and they will be woken up by a beacon signal from the unmanned aerial vehicle for data transmission. Unlike opportunistic Aloha protocol, a well-known unmanned aerial vehicle–wireless sensor network media access control protocol, the adaptive-opportunistic Aloha adds a handshake into every time interval of transmission to help enhance the throughput with an acceptable level of system bit error rate. Experiment results have shown that the proposed media access control protocol can improve the overall throughput of unmanned aerial vehicle–wireless sensor network systems by more than 30% over opportunistic Aloha.