Block error rate performance of subcarrier intensity modulation based optical wireless communication systems is analysed over Gamma–Gamma and lognormal atmospheric turbulence channels. The analysis is applicable to non-coherent binary modulations and coherent binary phase shift keying. The special cases of K-distributed strong turbulence channel and negative exponential turbulence channel are a...

We have generated a single-wavelength data signal with a data capacity of 5.1 Tbit/s. The enabling techniques to generate the data signal are optical time-division multiplexing up to a symbol rate of 1.28 Tbaud, differential quadrature phase shift keying as data format, and polarisation-multiplexing. For the first time, error-free performance with a bit error rate less than 10(-9) is demonstrat...

In recent years, chaotic communication is a hot research topic and it suits better for the emerging wireless networks because of its excellent features. Different chaos based modulation schemes have evolved, of which the CS-DCSK modulation technique provides better BER performance and bandwidth efficiency, due to its code domain approach. The QCSK modulation technique provides double benefit: h...

In diverse engineering problems including wireless communications, the estimate of the signal-to-noise ratio (SNR) is required. In this study, the authors develop a shrinkage-based SNR estimator in the data-aided and non-dataaided schemes for higher M-ary phase-shift-keying (M ≥ 8) and quadrature amplitude modulations. The observed Cramér-Rao lower bound is used as the variance of the expectati...

In August of 2005, the Mars Reconnaissance Orbiter (MRO) was launched. Its mission is to orbit Mars, performing remote sensing of the planet. Its mission will either introduce new, or greatly expand upon, deep space telecommunication capabilities. To support the MRO requirements, there have been multiple changes implemented in NASA's Deep Space Network. These changes include the first deep spac...

In this paper, a dual-hop relay based on channel state is studied. In the conventional relay scheme, a relay uses the same modulation method without reference to channel state. But, a relay uses an adaptive modulation method with reference to channel state. If the channel state is poor, a relay eliminates latter 2 bits and uses Quadrature Phase Shift Keying (QPSK) modulation. If channel state i...

The authors report on the downlink performance of a 10 Gb/s long-reach and ultra-dense wavelength-division multiplexed passive optical network, based on a multicarrier transmitter realized by using an externally injected gain-switched distributed-feedback laser diode. Each of the comb channels, spaced by 10 GHz, is modulated with a 3 Gbaud dual polarization quadrature phase shift keying signal ...

In this paper we transmit different complimentary codes using QPSK (Quadrature phase shift keying) modulation technique. The signal which is transmitted is scattered back from the target and send to the receiver for the demodulation. Using matlab a digital processing algorithm is designed for resolving range resolution and Doppler localization of a target using different complimentary codes lik...

Data-aided symbol synchronization for bursty communications utilizes a predetermined modulation sequence, i.e., a preamble, preceding the payload. For effective symbol synchronization, this preamble must be designed in accordance with the modulation format. In this paper, we analyze preambles for shaped offset quadrature phase-shift keying (SOQPSK) waveforms. We compare the performance of sever...

In this paper, we theoretically and experimentally demonstrated the residual chromatic dispersion (CD) monitoring of 100-Gbit/s carrier suppress return-to-zero differential quadrature phase shift keying (CS-RZ DQPSK) signals by evaluating the asymmetry ratio of delay tap asynchronous sampling. This scheme can easily differentiate the positive and negative residual CD of the fiber link. The reso...