Bit Error Rate Expressions Research Articles

Advanced spatial modulation for efficient MIMO‐based B2B communications in sporting activities

In this study, advanced multiple-input multiple-output (MIMO) techniques for body-to-body (B2B) sensor-based communication for sporting activities like running and cycling under different scenarios have been proposed. Enhanced spatial modulation and spatial media-based modulation have been investigated for efficient MIMO-based B2B communication. Special sensors have been proposed to deploy such techniques. Lognormal (LN) mixture model has been used because it can address the shadowing effects in B2B communication for such activities. Since LN mixture cannot yield closed-form expressions, it has been approximated using mixture of gamma (MG) distribution to achieve closed-form expressions for bit error rate (BER) in MIMO-based B2B communication for the first time. The system performance for the proposed methods has been analysed in terms of BER and theoretical upper bound expressions using MG distribution have been verified by Monte Carlo simulations.

Impact of Atmospheric Turbulence, Pointing Error, and Traffic Pattern on the Performance of Cognitive Hybrid FSO/RF System

Atmospheric turbulence conditions and mis-alignment in the free space optical (FSO) link are prime factors which necessitate the requirement of a back up radio frequency (RF) link to improve the link availability of the FSO systems. However, the utilization of this back-up RF link is limited. The RF channel which is meant chiefly as a back-up resource in case of FSO link failure, can be utilized more efficiently. In this work, it is attempted to improve the utilization of this RF resource. A second FSO link is converted to a Cognitive Hybrid FSO/RF link by accessing the already existing RF in the cognitive interweave mode. RF utilization factor is a measure of the efficiency with which the two FSO links utilize the same RF resource. The system performance is evaluated on the basis of RF utilization, outage probability and bit error rate (BER) under atmospheric turbulence and mis-alignment. Further, the impact of data traffic characteristics on system performance has been investigated. Closed form expressions for RF utilization, outage probability and BER have been derived for various traffic conditions. The analytical results have been verified through simulations. Results indicate improved system performance and better overall utilization of the RF resource.

Bit Error Rate Analysis for Modulating Retro-Reflector Free Space Optical Communications With Adaptive Threshold Over Correlated Gamma Gamma Fading Channels

Bit error rate (BER) performance for modulating retro-reflector (MRR) free space optical communication (FSOC) system with an adaptive threshold over correlated gamma-gamma fading channel is investigated. In order to do this analysis, we first derive two closed form expressions for the probability density function of the correlated MRR channel and our instantaneous BER using the optimal adaptive threshold without channel state information (CSI). Then based on these results, we develop a closed form expression for the average BER in the infinite series form whose convergence is confirmed by Cauchy's ratio test. Simulation results show that we can achieve small SNR penalty of 0.32 dB between our system and the system with CSI by constructing our adaptive threshold using 3 bit pilot data corresponding to a slight throughput reduction.

BER analysis using zero-forcing linear precoding scheme for massive MIMO under imperfect channel state information

ABSTRACTIn massive MIMO systems, inter-user interference has effect on the transmitted signals, so linear precoding techniques are employed for multiuser transmission channels to remove this inter-user interference. It is very complicated to design a suitable linear precoding technique having low computational complexity, which will give an excellent Bit Error Rate (BER) performance. In this paper, we analyse BER under imperfect Channel-State-Information (CSI) using Zero-Forcing (ZF) linear precoding scheme in the downlink, massive MIMO in Time-Division-Duplex (TDD) mode. We derive the closed-form expressions for BER that are obtained from the new expressions derived for Signal-Interference-Noise Ratio (SINR), and then analysis with different parameters using numerical and Monte Carlo simulated results is carried out in MATLAB under imperfect CSI. It was found that our theoretical analysis agrees well with the simulated results. In our analysis, BER was observed in most cases to be good when the number of Base Station (BS) antennas is large enough to accommodate the served users, but when the number of users grows up, the BER performance degrades depending on how many BS antennas are capable of handling the additional users. Also, increasing the downlink transmit power was found to improve the performance, but it is not an energy-efficient way for massive MIMO.

Research on the system performance of Gaussian minimum-shift keying with M-distribution in satellite-to-ground laser communication

In this paper, a Gaussian minimum shift keying (GMSK) modulation based on M-distribution is proposed for uplink satellite-to-ground laser communication systems. Considering the noise caused jointly by intensity scintillation, beam wander and angle of arrival (AOA) fluctuations in the satellite-to-ground laser uplink communication, the closed-form expression of bit error rate (BER) of GMSK modulation system is derived. The system performance under weak, medium and strong turbulence is studied. The relationship between signal-to-noise ratio and BER is analyzed using simulations, and compared with the differential phase shift keying modulation currently used in the satellite-to-ground laser communication systems. Furthermore, the effects of zenith angle, receiver aperture, transmitter beam radius and divergence angle on the system performance are studied. This research work provides guidance for system performance analysis of uplink satellite-to-ground laser communication.

Performance Analysis of Cell-Center Users in NOMA Based-Spectrum Sharing Protocol

This letter presents a non-orthogonal multiple access (NOMA) based cooperative spectrum sharing protocol to preserve the quality-of-service of cell-center primary users, where secondary transmitter cooperates with the primary to achieve full rate through cooperative multiplexing. In this correspondence, we derive the closed-form expression for average bit error rate and investigate the performance of primary users. Further, we present Monte Carlo simulation results to validate the mathematical framework derived.

Cooperative Time Successive SSK-M-ary Modulation for Decode-and-Forward Relay Systems

Space shift keying (SSK) is a single radio frequency (RF) chain multiple-input multiple-output (MIMO) scheme that uses the index of transmit antennas for information transmission. Time successive SSK- $ M$ -ary modulation (TSSM) and multi RF chain TSSM (MRF-TSSM) are recent MIMO techniques that achieve second order transmit diversity. We propose two cooperative relaying systems to attain distributed diversity in addition to transmit diversity of TSSM and MRF-TSSM. Cooperative-TSSM-1 (Coop-TSSM-1) uses multibranch relaying where TSSM is used in orthogonal time slots during the cooperative phase. Coop-TSSM-2 maps symbols to lower order constellations at multiple relays for simultaneous transmission of information using MRF-TSSM. We consider Decode-and-forward (DF) relaying where relays that correctly detect symbols forward it. We analyze the average number of relays that participate in cooperation, the end-to-end performance using a tight upper bound on the bit error rate (BER) and the asymptotic BER expressions to analyze diversity orders of both cooperative systems. We validate all analyzes using simulation results. From the analysis and results we show that Coop-TSSM-1 achieves better diversity order compared to Coop-TSSM-2 at the cost of higher number of time slots for completing the cooperative phase. Further in Coop-TSSM-2, results indicate that different constellation mappings used in MRF-TSSM during cooperative phase impact the BER performance. By applying spatial modulation based transmit diversity and $M$ -ary Modulation systems in the cooperative setups of Coop-TSSM schemes, performance comparison is given which highlights the significance of Coop-TSSM schemes.

Performance analysis at far and near user in NOMA based system in presence of SIC error

Non-orthogonal multiple access (NOMA) scheme is an emerging 5G technology to improve upon the spectral efficiency. It can support more users than the number of available frequency-,time-, and code-domain resources. The innovation behind NOMA technology is to exploit non-orthogonal resource allocation at the cost of receiver complexity to mitigate the inter-user interference arising due to non-orthogonal signals. In this paper, we present performance analysis of downlink NOMA (DL-NOMA) system in presence of successive interference cancellation (SIC) error over Rayleigh fading channels. In particular, we derive the exact closed-form expressions of bit error rate (BER) at near-user (U1) and far-user (U2) for the considered DL-NOMA system. Besides, we also present the achievable rate analysis of the considered NOMA system and it is observed that its achievable rate is higher as compared to conventional orthogonal multiple access (OMA) schemes. Further, we also determine the optimized power allocation coefficient for the NOMA system. The analytical results are corroborated with the Monte-Carlo simulations. The simulation results are presented for different modulation schemes and for different NOMA scenarios. A close argument between the analytical and simulation results validate our analysis.

Performance analysis of circle polarization shift keying modulation over the exponentiated Weibull distribution

The average bit error rate (BER) and outage probability of circle polarization shift keying (CPOLSK) modulation in free-space optical (FSO) system operating under exponentiated Weibull (EW) distribution are studied. The closed expression of the average BER is derived by generalized Gauss–Laguerre polynomials. The analytical results show the relationship between the average BER and average signal to noise ratio (SNR) of CPOLSK modulation with the effect of aperture averaging under different turbulence strengths and it is compared with on–off keying (OOK) modulation. The relationship between the outage probability and normalized threshold SNR of CPOLSK modulation is studied as well. All the analytical results are verified by the Monte Carlo simulation.

A novel chaotic modulation approach of packaged antenna for secured wireless medical sensor network in E‐healthcare applications

AbstractThis article first time reports the chaotic modulation approach toward RF signal processing for secured wireless medical sensor network (WMSN) in E‐healthcare applications. A Lorenz based chaotic modulation approach is implemented which provides lowest bit error rate (BER). The definite analytical expressions for BER in a differential chaos‐shift keying (DCSK) modulation scheme is derived and it predicted good correlation between simulated and theoretical. It is observed that proposed Lorenz chaos‐based DCSK modulation scheme is a potential candidate to provide high security in the patient data for WMSN. An off‐body UWB slotted antenna is designed which could avoid limitation of short‐range distance like implanted ones. The entire work includes numerical, simulated and experimental data in three phases. In first phase, Lorenz chaotic oscillator with electronics compatibility is executed which acts as data acquisition unit and demonstrates two‐dimensional and three‐dimensional chaos attractors. While in the second phase, analysis of BER achieves value of less than 10−4 by providing pseudorandom bit sequence at 5 Gb/s. A chaos modulated envelope using Lorenz based DCSK modulation is obtained by delay element γ. Finally, the third phase is designed on‐wafer off‐body antenna and demonstrates 3.1 to 10.6 GHz UWB toward RF signal processing in E‐healthcare applications.

MIMO-OFDM in a Cooperative Frequency Selective Fading Channel: An Analysis

Diversity is an integral technique in the advancement of wireless communications. Multiple-input multiple-output (MIMO) technology continues to occupy a pivotal position in the fourth-generation (4G) standards and beyond. With the advent of full-dimension (FD) MIMO and massive MIMO, new paradigms are being targeted in the disruptive technology. Third-generation partnership project (3GPP) has also emphasized the advanced MIMO technology for achieving its vision of International Mobile Telephony (IMT) 2020. However, implementing multiple antennas can be cumbersome due to limiting factors such as size, cost, and hardware limitations. In such a scenario, where implementing many antennas is not feasible, the benefits of diversity can be reaped by employing cooperative communication. Single antenna mobiles can share their mobile stations giving rise to a virtual MIMO system. In this paper, the authors have analyzed the performance of cooperative mobile stations in a frequency selective channel. Orthogonal frequency division multiplexing (OFDM), known for its robustness against multipath fading, is the modulation technique employed to circumvent the hazardous effects of intersymbol interference (ISI). MIMO is the key technology for achieving capacity advantage and improving link reliability. The blend of these two cutting edge technologies in a cooperative relay system presents encouraging results and inferences. Maximal Ratio Combining (MRC) is employed at the relay and the receiver to maximize the signal-to-noise ratio (SNR). Decode and forward (DF) protocol is used at the relay node owing to its regenerative nature and adaptability. The closed-form expressions for bit error rate (BER) and outage probability (Pout) are derived and compared with the experimental results. The effect of power decay factor is analyzed and simulation is done for 2 × 2, 2 × 3, and 2 × 4 transmit and receive antennas. The number of antennas at the relay is kept as 2. The analytical results agree with the simulation results.

BER Analysis of NOMA-Enabled Visible Light Communication Systems With Different Modulations

Visible light communication (VLC) and non-orthogonal multiple access (NOMA) are deemed two promising technologies in the next generation wireless communication systems in achieving high capacity and massive connectivity. In this paper we study the performance of a NOMA-enabled VLC system using different modulation schemes. In particular system level bit error rate (BER) is derived for different modulation schemes. Conventional methods used for analyzing the BER under orthogonal multiple access cannot be directly applied to NOMA. In order to obtain the closed-form BER expressions for the NOMA-enabled VLC systems, an analytical framework based on bitwise-decision axis and signal space is proposed.Moreover, the analysis method can be extended to the any wireless communication networks with NOMA. Simulation results demonstrate the accuracy of the theoretical analysis. The study shows that the BER gap among users decreases with the increase of the modulation order but at the cost of a higher power consumption in order to achieve a better signal to noise ratio. It is observed that 8-PSK modulation in NOMA-enabled VLC systems strikes a good tradeoff between the power cost and the achievable BER.

Performance Analysis of Cell-Center Users in SM-Based Cooperative Spectrum Sharing Systems

This letter presents full-rate cooperative spectrum sharing protocol where both primary and secondary transmitters are allowed to transmit simultaneously on the same frequency channel by using orthogonal spatial modulation technique. This proposed scheme can optionally enable secondary receiver as a full-duplex fixed decode-and-forward cooperative relay to maintain quality-of-service (QoS) of the cell-edge users. Considering two different modes, i.e., cooperative relay mode for cell-edge users and cooperative non-relay mode for cell-center users, we derive the closed-form expressions for the average bit error rate (BER) of both primary and secondary receivers.

Performance analysis of free space optical communication systems over imprecise Málaga fading channels

In this paper, we investigate the performance of free space optical (FSO) communication systems over imprecise Málaga (M) turbulence induced fading channel, which is the generalized form of the Gamma–Gamma and K turbulence channels as well. In the analysis we first derive the probability distribution function and cumulative distribution function of the channel’s fading coefficient in the presence of channel estimation error. Then, we obtain the exact closed-form expressions of average bit error rate (BER), outage probability (OP), and ergodic channel capacity to quantify the performance of the considered system. Additionally, to provide further insights about the system performance in high signal-to-noise ratio (SNR) regime, the asymptotic expressions of BER and OP are obtained. Furthermore, analytic results are successfully validated with Monte-Carlo simulations. The results show that the imprecise channel estimation has detrimental effects on the performance of FSO communication systems over M turbulence channels, e.g., an estimation error of 5% results in approximately 8 dB SNR loss for the BER value of 5×10−2.

BER analysis of amplify-and-forward relaying FSO systems using APD receiver over strong atmospheric turbulence channels

<span lang="EN-US">In this paper, we theoretically analyze the performance of amplify-and-forward (AF) serial relaying free-space optical (FSO) systems using avalanche photodiodes (APD) and subcarrier quadrature amplitude modulation (SC-QAM) over strong atmospheric turbulence channels modelled by gamma-gamma distribution. Closed-form expression for average bit error rate (BER) of system is theoretically derived talking into account APD shot noise, thermal noise as well as the impact of atmospheric loss and turbulence. The numerical results show that using AF relay stations can extend the transmission distance and help to improve performance of FSO system significantly when compared with the direct transmission. Moreover, the selection of APD gain value is indispensable to the system performance. The proposed system could be achieved the best performance by selecting an optimal APD gain value. In addition, the optimal value of APD gain also significantly depends on various conditions, such as link distance, the number of relay stations and APD receiver noise.</span>

Code-Index Modulation Aided Quadrature Spatial Modulation for High-Rate MIMO Systems

In this correspondence paper, a novel code-index modulation (CIM) aided quadrature spatial modulation (QSM) scheme, called CIM-QSM, is proposed for highly spectrum and energy efficient multiple-input multiple-output (MIMO) systems. The CIM-QSM scheme transmits information over three different transmit entities: modulated symbols, activated antenna indices, and spreading code indices. Hence, a higher efficiency in terms spectrum and energy use, and better error performance compared to the conventional direct sequence spread spectrum, spatial modulation (SM), QSM, and CIM aided SS (CIM-SS) schemes are obtained by the CIM-QSM technique for MIMO communication systems. Analytical expressions for the average bit error rate, energy efficiency, and throughput of the CIM-QSM system are performed and the theoretical results are validated with Monte Carlo simulation results.

Design and performance evaluation of bitwise retransmission schemes in wireless sensor networks

The previously proposed bitwise retransmission schemes which retransmit only selected bits to accumulate their reliability are designed and evaluated. Unlike conventional automatic repeat request (ARQ) schemes, the bitwise retransmission schemes do not require a checksum for error detection. The bitwise retransmission decisions and combining can be performed either after demodulation of the received symbols or after channel decoding. The design and analysis assume error-free feedback, however, the impact of feedback errors is also considered. The bit-error rate (BER) expressions are derived and verified by computer simulations in order to optimize the parameters of the retransmission schemes. The BER performance of coded and uncoded bitwise retransmissions is compared with a hybrid ARQ (HARQ) scheme over additive white Gaussian noise (AWGN), slow fading, and fast fading channels. It is shown that bitwise retransmissions outperform block repetition coding (BRC) over AWGN channels. In addition, the selection diversity created by the bitwise retransmissions can outperform the HARQ at large signal-to-noise ratio (SNR) over fast fading channels. Finally, the practical design of a bitwise retransmission protocol for data fusion in wireless sensor networks is presented assuming Zigbee, WiFi and Bluetooth system parameters.

Closed-Form Expression for BER of CE-OFDM in Optical Intensity-Modulated Direct-Detection Systems

A closed-form expression for the bit-error-rate (BER) of constant envelope orthogonal frequency division multiplexing (CE-OFDM) in intensity-modulated direct-detection optical systems is provided in this letter. To the best of our knowledge, this letter is the first that provides an expression of the BER that considers the impact of electrical phase modulation index, signal bandwidth, optical modulation index, and Mach–Zehnder modulator bias point. Simulation and experimental results are included to validate the accuracy of the expression, subject to an analysis of the impact of electrical phase modulation index and the level of subcarrier mapping. With the analytical expression, we are able to reduce the computation time in design and parameter optimization of optical systems based in the CE-OFDM.

Performance Analysis of TAS/SC as well as TAS/MRC MIMO Techniques under α-μ Fading Channels

Multiple-Input-Multiple-Output (MIMO) system improves performance as well as the capacity of the wireless system. The use of large number of antennas in a MIMO system increases the hardware complexities and also its price. To overcome this, MIMO systems that activate single transmit antenna at a time, namely transmit antenna selection (TAS) is considered in this paper. Selection combining (SC) and Maximal ratio combining (MRC) are carried out at the receiver over   fading channels. Expressions for outage probability and average bit error rate (ABER) are derived considering TAS/SC as well as TAS/MRC MIMO systems. All the derived expressions are validated by Monte-Carlo simulation results.

BER performance of FSOC system with differential signaling over partially correlated atmospheric turbulence fading and partially correlated pointing errors

Bit error rate (BER) performance of the free space optical communication (FSOC) systems using differential signaling over partially correlated atmospheric turbulence fading with and without partially correlated pointing errors is investigated. In order to do the BER performance analyses, we first derive a useful mathematical expression for the joint probability density function of the system under combined effects of the partially correlated atmospheric turbulence fading and partially correlated pointing errors. Then based on this obtained result, two mathematical BER expressions of the system affected by either the partially correlated atmospheric turbulence or both the partially correlated atmospheric turbulence fading and the partially correlated pointing errors are obtained. The accuracy of the derived BER expressions is demonstrated by the Monte Carlo simulations, and the effects of the system parameters on the BER performance are studied. From the simulations, we present some important and interesting analytical results of the BER performance with the system parameters.