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. 
Szil\'ard Andr\'as, \'Arp\'ad Baricz
cs.IT math.CA math.IT