Mobile digital communications via tone calibration

Error-Bound Formulation for Multichannel Reception of<tex>$M$</tex>-DPSK and Pilot-Aided<tex>$M$</tex>-PSK Over Rayleigh-Fading Channels With Postdetection Combining

“…Based on pervious analysis given in [14]- [17], this paper assumes that Manchester encoding (also known as biphase line coding) is used to create a spectral null at the direct current (dc) level of data signal spectrum, so that the pilot tone can be inserted without interference to the data signal. 2 For PTA -CPSK, the equivalent baseband transmitted signal is the summation of the data signal and pilot signals , i.e.,…”

“…In this analysis, the PF is assumed to be an ideal bandpass filter, i.e., the equivalent lowpass form of PF is an unity gain rectangular filter with bandwidth of . To avoid distortion due to filtering, the value of must be equal to or greater than the bandwidth of the power spectrum of the received pilot signal [14], [16], [17]. In the case of land mobile radio environments, the bandwidth of the received pilot-tone signal-power spectrum can be spread up to twice of the maximum Doppler frequency [5].…”

Rayleigh fade compensation QPRS coherent mobile radio modems operated at a practical 2 b/s/Hz efficiency

“…In the case of 10kb/s systems, to track the Doppler spread fD of lOOHz (corresponding t o a carrier frequency of 9OOMHz and a vehicular speed of 70mph), we would require a BPF of bandwidth at least 200Hz. In order t o reduce the stringent requirement of constructing a very narrow filter at IF, TCT calibration systems could also be implemented in baseband as shown in [3]. For a low bit rate system, this would mean a considerable data interference into pilot, in modulation schemes such as BPSK and QPSK, which have a considerable low frequency energy content.…”

Performance Evaluation of some Modulation Techniques for Radio Frequency Identification (RFID) System under different communication channels

“…It is now in use due to the demand of higher bandwidth efficiency [17], especially for data transmission in mobile communications. Multilevel quadracture amplitude modulation (M-QAM) is an attractive modulation technique for wireless communications because of its high spectral efficiency [4], [18].…”