A novel approach to transmitting two vector signals using a single optical carrier based on IQ modulation and coherent detection is proposed and demonstrated. In the proposed system, two quadrature phase-shift keying (QPSK) signals are IQ modulated on an optical carrier with one polarization state using a dual-parallel Mach-Zehnder modulator (DP-MZM). The optical carrier with an orthogonal pola...

Modulation plays an important role in transmission of single from transmitter to receiver in all communication systems. But it is vital in wireless communication and a lot of communication features including (data rate, error rate, symbol rate, bandwidth etc) depends upon it. In NS2 wireless network simulation BPSK is used for digital encoding and modulation of data [1,2]. The BPSK method is us...

Adaptive digital modulation in the optical domain is performed using an integrated optical modulator with a high symbol rate of 10 Gbaud. The optical digital-to-analogue conversion technique that employs an optical IQ modulator and a dual-polarization quadrature-phase-shift-keying (DP-QPSK) modulator is applicable to binary PSK, QPSK, and 16-ary quadrature amplitude modulation. Analogue modulat...

The characteristics of the decision feedback carrier recovery loop (DFL) for conventional QPSK signaling is evaluated experimentally through measurements of the carrierto-noise ratio of the regenerated carrier, lock range, acquisition waveforms and bit error rates. The results show that the DFL hardly exhibits inferiority to the ideal synchronization by designing the loop natural frequency adeq...

The modulators are the essential demand of communication systems they are designed to scale back the channel distortion & to use in RF communication therefore several sort of carrier modulation techniques has been already projected consistent with channel properties and rate of the system. Modulation is that the method of causation knowledge signal over carrier signal to attenuate the noise or ...

Modulation techniques have concerned increasing attention in optical wireless communications. Downlink transmission (base station to mobile terminal) using high data rate Mary Quadrature Amplitude Modulation (QAM), Quadrature Phase Shift Keying (QPSK) and Binary Phase Shift Keying (BPSK) modulation schemes are considered in a Wideband-Code Division Multiple Access (W-CDMA) system. QPSK or Quadr...

The exponentially-growing mobile data traffic imposes significant demands on the capacity of the mobile network. Fiber optic and microwave links are two main solutions for the mobile backhaul network, which provides connectivity between radio base station (RBS) sites and the switch sites. As compared to fiber, a microwave solution is much easier to deploy, however, its capacity is lower. This t...

We present FPGA-based emulation of a synchronous phase-coded quantum cryptography system. Several of the emulated subsystems are used for implementation in a free space demonstrative QPSK scheme for quantum key distribution with continuous variables (CV-QKD) using a base and optical phase synchronization. The CV-QKD systems are commonly implemented using QPSK modulation with switched or simulta...

In this thesis we have proposed a power efficient transmission scheme, CPMSC-IFDMA, for uplink LTE. In uplink LTE, efficiency of the transmitter power amplifier is a major concern, as the transmitter is placed in the mobile device which has limited power supply. The proposed scheme, CPM-SC-IFDMA, combines the key advantages of CPM (continuous phase modulation) with SC-IFDMA (single carrier freq...

Quadrature phase-shift keying (QPSK) and 16-quadrature amplitude modulation (16QAM) formats are deployed in inter-data center networks where high transmission capacity spectral efficiency required. However, intra-data networks, a four-level pulse (PAM4) format is to satisfy the requirements for simple low-cost transceiver configuration. For seamless effective connection of such heterogeneous wi...