<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...

there was a rapid development in wireless network area focusing on high speed and long range application. For this purpose Zigbee technology was developed. Zigbee based devices operates usually three bands i.e. 868 MHz, 915 MHz, and 2.4 GHz. This paper explore about several blocks of transmitter using VHDL. The transmitter consist of CRC(cyclic redundancy check), Bil-to-Symbol block, symbol-to-...

This article discusses QPSK, OQPSK, π/4 DQPSK and the trade offs involved. Later we discuss various CPM schemes and their relative bandwidth efficiencies. Probability of Bit error is discussed for various schemes assuming an AWGN channel. A model is devised, ignoring any changes in phase, to determine the error probabilities for flat fading channels. The article ends with a brief discussion of ...

We study simple trellis-based detectors for SOQPSK that have a minimal level of complexity. In particular, we show that the state complexity can be cut in half relative to previous approaches—from 4 states down to 2—with asymptotically optimum performance. We give two possible means of achieving this: the pulse amplitude modulation (PAM) technique and the pulse truncation (PT) technique; both o...

Fifth generation (5G) wireless networks must meet the needs of emerging technologies like Internet Things (IoT), Vehicle-to-everything (V2X), Video on Demand (VoD) services, Device to communication (D2D) and many other bandwidth-hungry multimedia applications that connect a huge number devices. 5G demand better bandwidth efficiency, high data rates, low latency, reduced spectral leakage. To the...

in scpc-dama satellite networks, the baseband rrc pulse shaping is utilized to reduce the bandwidth and inter symbol interference (isi). but the variation in carrier's envelope, which expands the spectrum and ultimately increases the bandwidth, causes isi and quadrature channel crosstalk (qcc). the goal of this paper is to introduce a method to shape baseband rrc pulses, in order to make a near...