Bit Error Rate Simulations Research Articles

Parameter optimization of a Josephson latching driver based on bit-error-rate simulations

We have calculated a bit-error-rate (BER) of Josephson latching drivers using the Monte-Carlo simulations taking into account the thermal noise at the Josephson junctions. The latching driver under investigation is composed of parallel 8-junction stacks and a SQUID input gate. We have optimized the structure of the SQUID input gate based on the BER simulation to get larger bias margins with acceptable BER.We have shown that the bias margins of the latching driver with a 3-junction SQUID input gate are better than that using a 2-junction SQUID input gate. The high-speed measurement of the Josephson latching driver confirms the validity of the BER based optimization. We have obtained the BER lower than 10−12 at 5GHz and 10−5 at 10GHz in the Josephson latching driver with the 3-junction SQUID input gate by the high-speed test.

Feedback assisted stochastic gradient adaptation of multiantenna transmission

This paper describes a feedback assisted stochastic gradient algorithm for adapting the weights of a multiantenna transmitter in a multiuser multiple-input single-output per user (MISO) communication system, which yields both a power delivery (aperture) gain and a fading channel diversity gain from the multiple transmit antennas. Feedback from the receiver is used to attain partial channel state information at the transmitter, which attempts to maximize the power delivered to the receiver. The system utilizes a perturbation probing and update formulation: a vector perturbation probe is transmitted and perturbation sign feedback from the receiver defines the transmitter weight vector additive update. This feedback provides a coarse estimate of the gradient of the delivered power and is used to adapt the multiantenna baseband weights of the transmitter. The second moment update of the algorithm is derived, and the tracking performance of the algorithm applied to a dynamic AR1 fading channel is analyzed, with simulations confirming the analysis. Bit-error rate simulations in a dynamic fading channel show that the algorithm can perform as well or better than previously proposed vector selection feedback, and in slower fading the algorithm substantially outperforms diversity space time coding.

Reduction of nonlinear intrachannel effects by channel asymmetry in transmission lines with strong bit overlapping

We have examined the statistics of simulated bit-error rates in optical transmission systems with strong patterning effects and have found strong correlation between the probability of marks in a pseudorandom pattern and the error-free transmission distance. We discuss how a reduced density of marks can be achieved by preencoding optical data.

On the UWB system coexistence with GSM900, UMTS/WCDMA, and GPS

This paper evaluates the level of interference caused by different ultra-wideband (UWB) signals to other various radio systems, as well as the performance degradation of UWB systems in the presence of narrowband interference and pulsed jamming. The in-band interference caused by a selection of UWB signals is calculated at GSM900, UMTS/wideband code-division multiple-access (WCDMA), and Global Position System (GPS) frequency bands as a function of the UWB pulsewidth. Several short-pulse waveforms, based on the Gaussian pulse, can be used to generate UWB transmission. The two UWB system concepts studied here are time hopping and direct sequence spread spectrum. Baseband binary pulse amplitude modulation is used as the data modulation scheme. Proper selection of pulse waveform and pulsewidth allows one to avoid some rejected frequency bands up to a certain limit. However, the pulse shape is also intertwined with the data rate demands. If short-pulses are used in UWB communication the high-pass filtered waveforms are preferred according to the results. The use of long pulses, however, favors the generic Gaussian waveform instead. An UWB system suffers most from narrowband systems if the narrowband interference and the nominal center frequency of the UWB signal overlap. This is proved by bit-error rate simulations in an additive white Gaussian noise (AWGN) channel with interference at global system for mobile communication (GSM) and UMTS/WCDMA frequencies.

Performance of parallel and serial concatenated codes on fading channels

The performance of parallel and serial concatenated codes on frequency-nonselective fading channels is considered. The analytical average upper bounds of the code performance over Rician channels with independent fading are derived. Furthermore, the log-likelihood ratios and extrinsic information for maximum a posteriori (MAP) probability and soft-output Viterbi algorithm (SOVA) decoding methods on fading channels are developed. The derived upper bounds are evaluated and compared to the simulated bit-error rates over independent fading channels. The performance of parallel and serial codes with MAP and SOVA iterative decoding methods, with and without channel state information, is evaluated by simulation over independent and correlated fading channels. It is shown that, on correlated fading channels, the serial concatenated codes perform better than parallel concatenated codes. Furthermore, it has been demonstrated that the SOVA decoder has almost the same performance as the MAP decoder if ideal channel state information is used on correlated Rayleigh fading channels.

21-3 OFDMのスペクトラム波形を基にしたビット誤り率の推定

21-3 OFDMのスペクトラム波形を基にしたビット誤り率の推定

21-5 現行UHF放送波の受信状況データを基にしたOFDMのビット誤り率の推定

21-5 現行UHF放送波の受信状況データを基にしたOFDMのビット誤り率の推定

EVM and BER Simulation of an NADC-TDMA Radiophone Influenced by theOperator's Body in Urban Mobile Environments

This paper presents the performance evaluation of a portable digital radiophone influenced by the operator's body in urban mobile environments, based on the EVM (error vector magnitude) and BER (bit error rate) simulation. The type of digital modulation follows to the NADC-TDMA standard. A new probability density function (pdf) is proposed to describe the statistic of the EVM in an AWGN channel under frequency non-selective slowly fading situation. The simulation combines the modified Doppler power spectrum (MDPS) method and a gray coding (π/4-DQPSK modulation with square-root raised cosine (SRRC) shaping filter. The performance evaluation based on BER uses an ideal matched-filter-based receiver. The results show that the closer of the distance between the radiophone antenna and the operator's head, the poorer of the EVM and BER performance.

Decision-directed adaptive nonlinear canceller for optical read channels

A simple and yet effective scheme for asymmetry compensation in optical read channels is presented. The simplicity and effectiveness of this scheme make it an excellent candidate for a practical implementation in an optical signal recovery circuit. The performance of this asymmetry compensation scheme is evaluated using bit-error rate (BER) simulation. The results of this simulation show a significant improvement in BER performance when the compensator is included within the read channel circuit.

The performance of optical wireless OOK, 2‐PPM and spread spectrum under the effects of multipath dispersion and artificial light interference

Indoor wireless infrared transmission systems are mainly affected by ambient light-induced shot noise, multipath dispersion and the interference produced by artificial light sources. In this paper, spread spectrum techniques are proposed to combat multipath dispersion and artificial light interference. The bit error rate performance of the spread spectrum technique under the combination of these detrimental effects are studied and compared with that of OOK and 2-PPM. A novel analysis is derived to provide a simplified common analytical platform to facilitate the comparison among the three modulation schemes. Bit error rate analyses for OOK, PPM and spread spectrum taking into account the combined effects of multipath dispersion and artificial light interference are derived for the first time. Analytical, simulation and experimental results of bit error rate versus optical signal-to-noise ratio are then presented. The results show that spread spectrum techniques are very robust to multipath dispersion and artificial light interference. Copyright © 2000 John Wiley & Sons, Ltd.

The performance of optical wireless OOK, 2-PPM and spread spectrum under the effects of multipath dispersion and artificial light interference

Indoor wireless infrared transmission systems are mainly affected by ambient light-induced shot noise, multipath dispersion and the interference produced by artificial light sources. In this paper, spread spectrum techniques are proposed to combat multipath dispersion and artificial light interference. The bit error rate performance of the spread spectrum technique under the combination of these detrimental effects are studied and compared with that of OOK and 2-PPM. A novel analysis is derived to provide a simplified common analytical platform to facilitate the comparison among the three modulation schemes. Bit error rate analyses for OOK, PPM and spread spectrum taking into account the combined effects of multipath dispersion and artificial light interference are derived for the first time. Analytical, simulation and experimental results of bit error rate versus optical signal-to-noise ratio are then presented. The results show that spread spectrum techniques are very robust to multipath dispersion and artificial light interference. Copyright © 2000 John Wiley & Sons, Ltd.

Multistage multiuser detection for FHMA

A multistage multiuser detector (MMD) is presented for frequency-hopping/code-division multiple access (FH/CDMA.) The MMD reduces the bit-error rate (BER) over the conventional detector by exploiting prior knowledge of the addresses and energies of the user signals. This detector is a conservative multiuser detector which is robust to unknown users and has a complexity that is only linear in the number of users. The performance analysis of the synchronous MMD includes both theoretical and simulation BERs for the noiseless case as well as simulation results that include the presence of noise. The MMD is then extended to the fully asynchronous case which makes this work the first to propose an FH/CDMA multiuser detector for asynchronous communications. This asynchronous MMD is compared via simulation to the conventional detector.

Decision feedback postprocessor for zero-crossing digital FM demodulator

A baseband digital narrow-band FM receiver, called zero-intermediate frequency zero-crossing demodulator (ZIFZCD), has been developed. This demodulator may offer low complexity and simple implementation. However, the bit error rate (BER) performance of the ZIFZCD is inferior to that of the limiter-discriminator-integrate-and-dump (LDI) demodulator. In this paper, a simple decision feedback postprocessor (DFP) is proposed to improve the performance of the ZIFZCD. Analysis and simulation BER results of the ZIFZCD with the DFP are presented for minimum-shift keying (MSK) and Gaussian MSK (GMSK) signals under additive white Gaussian noise (AWGN) and mobile fading environments.

デジタル放送を支える伝送技術 フェージング伝送路におけるＯＦＤＭ用等化器の性能向上に関する一検討

We have studied frequency-and time-domain equalization techniques under fading conditions for the European DVB-T OFDM system. We first describe a frequency-domain equalizer using simplified linear interpolation in the symbol direction that estimates the channel response of receiving-data carriers by using the pilot-carrier channel response. We calculated the signal-to-interference ratio (SIR) and the bit error rate (BER) over one-path and two-path Rayleigh-fading channels. We found that an SIR of about 20 dB and a BER of less than 1.5 × 10-3 (QPSK and 16 QAM) are obtained even for a maximum doppler frequency of 50 Hz in a 2-k FFT system. We next describe a simplified time-domain equalizer using step interpolation over the OFDM useful period. A simulated BER of 2 × 10-3 (QPSK) over one-path Rayleigh-fading channels (fd =50 Hz) was attained for an 8-k FFT system, when the new time-domain and frequency-domain equalizer techniques were applied.

MLSE for correlated diversity sources and unknown time-varying frequency-selective Rayleigh-fading channels

Yu and Pasupathy (see ibid., vol.43, p. 1534-44, 1995) derived a maximum-likelihood sequence estimation (MLSE) receiver structure for unknown time varying frequency-selective Rayleigh-fading channels and uncorrelated diversity sources. This receiver design is extended to the case of correlated diversity sources. Correlated diversity sources typically arise with space diversity, where constraints on antenna volume require that diversity antennae be placed too closely together. Analytic and simulated bit-error rate (BER) curves are presented for receivers which exploit and ignore the correlation. In the former case, we find a small BER improvement that reduces with decreasing correlation. However, for a fixed receiver complexity, superior performance is achieved when the correlation is ignored.

Maximum-likelihood synchronization, equalization, and sequence estimation for unknown time-varying frequency-selective Rician channels

This paper develops a receiver structure to perform jointly maximum-likelihood (ML) synchronization, equalization, and detection of a linearly modulated signal transmitted over a time-varying frequency-selective Rician-faded channel, corrupted by additive white Gaussian noise (AWGN). The receiver is particularly suited to a fast-fading channel, where other receivers that rely on estimating the channel cannot track it quickly enough. The signal mean and autocovariance are needed, and a scheme is proposed for estimating these quantities adaptively. The receiver processes the specular and diffuse components (corresponding to the signal mean and autocovariance) separately. Processing the known specular component is the classical detection problem. The unknown diffuse component is processed by predictors. We show that the predictors can achieve synchronization in a novel manner, if synchronization is required. A union bound on the receiver's bit-error rate (BER) is derived, and it tightly bounds simulated BERs in fast-fading at high signal-to-noise ratios (SNRs).

Bit‐error rate performance of block‐coded modulation systems under rayleigh fading

AbstractA block‐coded modulation (BCM) system estimating the complex amplitude variations of a channel by Kalman estimation is proposed and evaluated in this paper. A differential BCM system estimating a channel equivalently by differential encoding, on Rayleigh fading channels, is also presented here. To evaluate the propagation characteristics of the proposed BCM systems accurately, the upper bounds of the bit‐error rate (BER) of BCM are derived, considering the estimation error of the complex amplitude variations of a propagation channel; the BER characteristics of the systems on Rayleigh fading channels are analyzed by the derived upper bounds of the BER and computer simulation. Analyses show that the upper bounds derived are effective in evaluating the BER characteristics of the BCM systems when there are channel estimation errors and the proposed BCM systems operate effectively even when channel estimation errors exist.

A novel digital FM receiver for mobile and personal communications

A digital baseband receiver called zero-intermediate frequency zero-crossing demodulator (ZIFZCD) was developed for digital FM signal detection. ZIFZCD is applicable to many worldwide mobile and personal communications systems. In addition, ZIFZCD offers lower power consumption and simpler implementation, compared to the conventional analog implementation [e.g., a limiter-discriminator integrator and dump (LDI)] and the conventional digital implementation [e.g., the cross-differentiate-multiply demodulator (CDM)]. This paper introduces the ZIFZCD and reports the bit-error rate (BER) of the ZIFZCD under both static and fading environments. The analyzed and simulated BER results show that the ZIFZCD is comparable to the conventional CDM for narrowband digital FM with a modulation index of 0.5, and the ZIFZCD is significantly better than the CDM for wideband digital FM with a modulation index larger than 1.5.

Simulation of bit error performance of FSK, BPSK, and pi /4 DQPSK in flat fading indoor radio channels using a measurement-based channel model

The results of a simulation study that provides insight into the simulation methodology and bit error rate (BER) performance of frequency-shift keying (FSK), binary phase-shift keying (BPSK), and pi /4 differential phase-shift keying ( pi /4 DQPSK) in flat fading channels inside open plan buildings are presented. A detailed measurement-based propagation channel model, SIRCIM (simulation of indoor radio channel impulse response models), which generates over 1000 closely spaced baseband equivalent complex impulse responses for a mobile radio operating at 1.3 GHz and traveling over a 1-m path, is used. The small-scale channel model, the communication system models used in the analysis and the methods used to predict BER are described. The channel simulator and the systems models have been thoroughly tested, and results from average instantaneous BER simulations are shown. The BER performances of the modulation techniques are presented. It is found that BPSK offers between a 2.8-dB and 3.0-dB improvement over pi /4 DQPSK, although the latter offers a 3-dB increase in capacity for a given spectrum allocation. >