The Ungerboeck and Forney observation models for offset QPSK are derived for three different representations for OQPSK. The representations and their corresponding Ungerboeck observation models are different, but the trellises used by the maximum likelihood sequence estimators possess the same complexity. The Forney observation models are obtained in straight-forward way for the bit-based repre...

We show that, similar to the trellis-coded modulation representation of MIL-STD shaped offset quadrature phase-shift keying (SOQPSK), offset quadrature phaseshift keying (OQPSK) can be decomposed into a “degraded” trellis encoder and a memoryless mapper. Based on the representations of OQPSK and MIL-STD SOQPSK as trellis-coded modulations, we investigate the potential coding gains achievable fr...

The bandwidth efficient modulation format OQPSK is implemented up to now merely in mobile radio systems which do employ spread spectrum techniques, i.e. it is not used in narrow band systems. This is due to the fact, that, in spite of its reduced performance degradation in non-linear channels in comparison to other linear modulation formats, for OQPSK no receivers were derived up to now, which ...

OQPSK modulation technique is used for designing Zigbee transceiver worldwide since several years of invention of ZigBee technology. It provides good battery life, better range and various other advantages for which Zigbee technology is known. But here we are discussing about the transceiver performance over the noisy channel. In noisy channel, we are proposing MSK based Zigbee technology and c...

In this paper, a comparison is made between the spectral regrowth of quadrature phase shift keyed (QPSK) and offset QPSK (OQPSK) signals as they go through non-linear amplifications. Contrary to existing approaches that assume the power amplifier input is Gaussian, our analysis is carried out without the Gaussian assumption, by using higher-order statistics. We show that it is possible to asses...

This article contains analyses of the performance of various carrier synchronization loops for offset quadrature phase-shift-keying (OQPSK) modulation, all motivated in one form or another by the maximum a posteriori (MAP) estimation of carrier phase. When they are implemented as either high or low signal-to-noise ratio (SNR) approximations to the generic implementation suggested by the MAP est...

The balanced modulator, which comprises two amplitude-modulation modules, is widely used in phase-modulated communication systems. In practice, the balance between these amplitude-modulation modules is difficult to maintain, and the amplitude and phase imbalances can cause distortion in the signal constellation and introduce undesired interfering tone signal components when such an imperfect mo...

Modulation plays an important role in transmission of signals from transmitter to receiver in all communication systems and the performance of digital modulation systems is of the most important key factors to achieve the best results of the communication process . This paper presents a comparative study of some performance parameters or performance metrics of a digital communication system wit...

<p><span>This study shows hybrid continuous-phase frequency shift keying (CPFSK)/optical quadrature-phase (OQPSK) modulation transmission techniques’ performance efficiency with return-to-zero (RZ) line coding scheme–based fiber systems in passive optical networks. Max. Q factor/min. bit error rate variations versus and length are studied detail for various bits/symbol, based on pro...

Part I1 of this report presents a new method to resolve the phase-ambiguity for Offset QPSK modulation systems. When an Offset Quaternary Phase-Shift-Keyed (OQPSK) communications link is utilized, the phase ambiguity of the reference carrier must be resolved. At the transmitter, two different unique words are separately modulated onto the quadrature carriers. At the receiver, the recovered carr...