New approximations for DQPSK transmission bit error rate

In this correspondence our aim is to use some tight lower and upper bounds for the differential quaternary phase shift keying transmission bit error rate in order to deduce accurate approximations for the bit error rate by improving the known results in the literature. The computation of our new approximate expressions are significantly simpler than that of the exact expression.Comment: 12 pages, 4 figures, 3 table

New Accurate Approximation for Average Error Probability Under κ−μ\kappa-\mu Shadowed Fading Channel

This paper proposes new accurate approximations for average error probability (AEP) of a communication system employing either $M$-phase-shift keying (PSK) or differential quaternary PSK with Gray coding (GC-DQPSK) modulation schemes over $\kappa-\mu$ shadowed fading channel. Firstly, new accurate approximations of error probability (EP) of both modulation schemes are derived over additive white Gaussian noise (AWGN) channel. Leveraging the trapezoidal integral method, a tight approximate expression of symbol error probability for $M$-PSK modulation is presented, while new upper and lower bounds for Marcum $Q$-function of the first order (MQF), and subsequently those for bit error probability (BER) under DQPSK scheme, are proposed. Next, these bounds are linearly combined to propose a highly refined and accurate BER's approximation. The key idea manifested in the decrease property of modified Bessel function $I_{v}$, strongly related to MQF, with its argument $v$. Finally, theses approximations are used to tackle AEP's approximation under $\kappa-\mu$ shadowed fading. Numerical results show the accuracy of the presented approximations compared to the exact ones