Error performance of frequency-hopped d.p.s.k. system

In order to accurately evaluate bit error rates for a frequency-hopped d.p.s.k. system, digital computer experiments were performed. The value of Eb/N0 at the 10?3 error rate without fading was 8.4 dB.     

Performance of multilevel d.c.p.s.k. system in the presence of both interchannel and intersymbol interference

A general model of a multilevel d.c.p.s.k. system is analysed in the presence of additive Gaussian noise, intersymbol interference and adjacent-channel interference. The symbol error probability is obtained by combining an analytical approach with a Monte Carlo simulation. Numerical results are presented as an example.     

Performance of a multilevel d.c.p.s.k. system in the presence of interference and Gaussian noise

Study of a multilevel d.c.p.s.k. system leads to the consideration of pairs of adjacent symbol vectors which depend on instantaneous levels. An analytic evaluation is made of symbol error probability for a general pair of such vectors in the presence of Gaussian noise.     

Error rate for p.s.k. and d.p.s.k. in the presence of source noise

The analysis of error rate in 2-level p.s.k. and d.p.s.k. systems has been extended to include the effects of source phase noise. Curves are presented for channel S/N ratios up to 6 dB and source phase deviations up to 0.6 rad r.m.s.     

Error rate performance for s.f.s.k. with cochannel and intersymbol interference

The probability of error of s.f.s.k., with matched-filter detection in the presence of additive white Gaussian noise, intersymbol interference and cochannel interference has been studied. Results are presented as a function of the signal/interference ratio for a system using a third-order Butterworth filter.     

Performance degradation of two-link binary c.p.s.k. system incorporating direct phase regenerator

The letter presents an analysis for the bit error probability (b.e.p.) of a two-link binary coherent phase-shift-keying (c.p.s.k.) system corrupted by additive Gaussian noise and consisting of a direct phase regenerator (d.p.r.) followed by a coherent receiver. Equivalent signal/noise ratio (s.n.r.) degradations due to imperfections in a practical d.p.r. are evaluated at the 10?6 b.e.p. point.     

Error-detection in a d.p.s.k. system

It is suggested that, by a suitable choice of the differential phases in a d.p.s.k. scheme, not only the differential phases can be estimated at the receiver, but also certain errors can be detected. This result is based upon the reflected Gray-code relation satisfied by the signs of certain trigonometric functions.     

Anti-hangup system for p.s.k. tracking loops

The design of an anti-hangup system for phase shift keyed (p.s.k.) signal tracking systems is reported. Digital simulation studies show that up to an order of magnitude decrease in phase acquisition time may be achieved.     

Optimum p.c.m. regenerator performance in presence of crosstalk

Minimum values of p.c.m. regenerator NEXT noise figure and FEXT noise figure are derived. The performance of regenerators with optimised cosine rolloff is within 0.2 dB of these minima, and that of commercial regenerators can be within 2 dB of the minima.     

Error probabilities due to atmospheric noise in practical m-c.p.s.k. and ideal f.s.k. receivers

An improved Cheby?shev approximative analytical expression for the probability distribution of the normalised envelope of atmospheric noise (a.n.) in narrowband receiver is presented. A new probabilistic interpretation of the derived expression is given, and the error probabilities for the m-c.p.s.k. receiver with finite-width decision threshold and an ideal f.s.k. receiver are calculated. The expressions obtained are explicit and they represent the weighted sum of the error probabilities due to Gaussian noises of different noise powers.     

Error probabilites for a.s.k./p.s.k. systems in an additive mixture of Gaussian and impulsive noise

A simple expression for the error probability for coherent a.s.k/p.s.k systems in an additive mixture of Gaussian and impulsive noise is obtained. It is shown that the impulsive noise considered may, in certain situations, be treated as conditionally Gaussian. This allows the above error probability to be expressed a weighted sum of the error probabilities due to Gaussian noises of different noise powers.     

Adjacent-channel interference in f.s.k. transmission

The performance of a frequency-shift-keying system is investigated as a function of the amount of adjacent-channel interference. New quantitative results are presented which show that, for a peak-to-peak frequency deviation of 0.7 times the bit rate and a receiver bandwidth of one times the bit rate, the frequency separation between channels can be reduced to about 1.6 times the bit rate without causing an undue amount of performance degradation.     

Error performance and throughput evaluation of a multi-Gbps millimeter-wave WPAN system in the presence of adjacent and co-channel interference

This paper investigates the impact of adjacent channel interference (ACI) and co-channel interference (CCI) on error performance and throughput of a multi-Gbps millimeterwave wireless personal area network (WPAN) system in a realistic residential line-of-sight (LOS) and non-line-of-sight (NLOS) multipath environment. The main contribution of this paper is providing a multi-Gbps WPAN system design in the challenging multipath environment in the presence of ACI/CCI. Based on the investigation results, we have provided ACI/CCI rejection as a reference for victim receiver protection design. In the NLOS environment, the ACI rejection (i.e. ACI that causes 0.5 dB degradation in the required signal-to-noise ratio (SNR) to achieve bit error rate (BER) of 10^-6) for pi/2-BPSK, QPSK, 8 PSK and 16 QAM are 13, 7, 0 and -6dB respectively. And the CCI rejection for similar modulation schemes are -18, -20, -26 and -29 respectively. Secondly, we have clarified the LOS-NLOS relationship of the ACI/CCI impact to system performance. ACI in multipath NLOS environment causes an additional 5 dB degradation to error performance as compared to ACI in the LOS environment. CCI on the other hand, has similar impact on error performance in both LOS and NLOS environment. Thirdly, we have clarified the relationship between modulation spectral efficiency and robustness against ACI/CCI. In an environment with no or low ACI/CCI, the maximum achievable throughput for pi/2-BPSK, QPSK, 8 PSK and 16 QAM in LOS environment are 1.2, 2.5, 3.8 and 5 Gbps respectively. In NLOS environment, the achievable throughput decreases to 1, 1.9, 2.8 and 3.8 Gbps respectively. As ACI/CCI increases, the throughput of higherorder modulation schemes such as 16 QAM decreases the most rapidly, followed by 8 PSK and QPSK. The throughput for pi/2-BPSK has the highest tolerance against increasing ACI/CCI, at the expense of lower maximum achievable throughput.     

Novel p.s.k. tanlock loop

A new loop for coherent demodulation of suppressed carrier phase-shift-keyed (p.s.k.) signals is presented. The p.s.k. tanlock loop (p.s.k.-t.l.l.) has a wider tracking range and faster phase acquisition than the Costas or squaring loops usually used for p.s.k. suppressed carrier tracking, but it has a greater tendency to false lock.     

Programmable p.s.k. diode convolver

Programmable phase-shift-key signal encoding and correlation is demonstrated using a unique s.a.w. diode-convolver configuration. Biphase tap programming is accomplished by choosing the polarity of the direct bias current applied to an antiparallel silicon-on-sapphire diode pair attached to each delay-line tap. This nonlinear approach also permits accurate correlation of an arbitrarily coded. Doppler-shifted p.s.k. signal. The experimental characteristics of a 64-tap programmable module are described.     

Improvements in coherent f.s.k. performance

It is shown that, provided that the phases of the mark and space frequencies are constant and satisfy a simple relationship, a filtered t.s.k. signal becomes a 2-phase p.s.k. signal, and may be coherently detected. Using a practical filter, the performance is within 2.2 dB of ideal p.s.k.     

Performance degradation of decision-directed c.p.s.k. demodulator due to uncompensated time delay of decision circuitry

The influence of the uncompensated time delay incurred in the nonoptimum symbol decision filter on the error performance of a decision-directed c.p.s.k. demodulator is considered. An iterative method for the probability of bit error computation is used.     

Novel technique for eliminating the ambiguity in p.s.k. signal detection

When a p.s.k. signal is synchronous, i.e. the transmitted signal is phase-locked to the data, it carries extra information which allows demodulation without ambiguity. A simple practical demodulator circuit is described, which, in long term use, has proved to be very successful.     

Good performance i.f. and premodulation filters for simple f.s.k. system

Results are given of a realisable i.f. filter that appears to give the best compromise design for the major performance parameters of an f.s.k. system: signal/noise ratio, intersymbol interference and tolerances to frequency and timing offsets. These results are determined by a computer f.m.-simulator program, keeping all the components ideal except the filters. In addition, various premodulation filters have been investigated, in conjunction with the i.f. filter, in terms of system performance.     

Generalised transient response of bandpass transfer functions to f.s.k.- and p.s.k.-type signals

A method that enables an accurate evaluation to be made of the instantaneous frequency response of bandpass filters is presented, and an explicit expression is derived for the general case of a constant-amplitude discontinuous-phase f.s.k. signal. Curves of responses of a 4-pole filter are included as an example, both for the continuous- and discontinuous-phase f.s.k. signal. A byproduct of this technique also permits the computation of the instantaneous phase and frequency response due to a p.s.k. signal.