A coherent optical beam forming network principle using phase-locked semiconductor lasers as sources is presented. For this scheme the spectral purity of the intermediate frequency derived from mixing the signals from two semiconductor lasers is considered and the relationship between the linewidths of the lasers in a satellite transmitter and the phase error at the detector of a microwave diff...

In this paper, the performance of orthogonal frequency division multiple access (OFDMA) uplink systems over time-varying frequency-selective Rayleigh fading channels is investigated. Expressions of the bit error rate (BER) performance for quadrature phase shift keying (QPSK) and quadrature amplitude modulation (QAM) signals under channel estimation errors are derived. Based on BER performance, ...

With more and more developments in wireless communication, spread spectrum modulation techniques have been widely used in various modulation systems. Frequency hopping technique is one of the types of spread spectrum system. In this paper, frequency hopping techniques are compared in a DBPSK modulation system which employs non coherent reception. Fast frequency hopping and multicarrier frequenc...

We propose a novel 3-bit/symbol optical data format based on simultaneously modulating dark-return-to-zero (DRZ), differential-phase-shift-keying (DPSK) and polarization-shift-keying (PolSK) on the same optical carrier. Transmission performance is investigated. The proposed data format has a more compact spectrum when compared with other modulation schemes (at the same data rate), such as retur...

This paper presents a novel data modulation scheme PCCD-OFDM-ASK: the phase continuous context dependent orthogonal frequency division multiplexing amplitude shift keying. The proposed modulation is successfully applied in the mobile payment system. It is used to transmit the digital data over the speech channel of the mobile communication system GSM, as well as CDMA. The main key points of the...

We show that inserting pilot tones with frequency intervals inversely proportional to the subcarrier index exhibits greatly improved dispersion estimation performance when compared to the equal spacing design in optical fast orthogonal frequency division multiplexing (F-OFDM). With the proposed design, a 20-Gbit/s four amplitude shift keying optical F-OFDM system with 840-km transmission withou...

To facilitate efficient two-way communication, we implemented the sliding window algorithm with configurable send and receive window sizes. To ensure reliability of our transmissions, we detected corrupted packets using either a checksum or a CRC (cyclic redundancy check), as well using LDPC (low density parity check) to do error correction. And in addition to DBPSK (differential binary phase s...

A method of digital signals transmission based on energy flow, aiming at solving message transmission in Wireless Power System (WPT) has been proposed. To realize the transmission of power and information simultaneously, the feature of the message is pouring into the energy wave without appending any auxiliary circuits but sharing the same inductor channel. At the receiver end, system could not...

Low-density parity-check (LDPC) codes provide capacity approaching performances with very long codes in a coherent channel. However, as the block length increases, their performance becomes worse with residual frequency offsets. Residual frequency offsets can be tackled with sub-block decoding and LDPC code-aided phase ambiguity resolution for binary phaseshift keying (BPSK) signals. Sub-block ...

The energy detection M-ary Gaussian frequency-shift keying (FSK) system is proposed in this paper. The system performance is analyzed in additive white Gaussian noise channels, multipath channels, and in the presence of synchronization errors. The numerical results show that the M-ary modulation achieves the higher data rate than the binary modulation. However, it also results in performance de...