This paper studies the effect of using higher order modulation formats in the performance of minimum mean-squared error (MMSE) receiver based direct-sequence (DS) code-division multiple access (CDMA) systems in terms of bit error rate (BER) at different loading levels in additive white Gaussian noise (AWGN) and slow fading channels. The performance of BPSK, QPSK, and 16QAM modulation formats ar...

In this paper, a complete super-regenerative QPSK receiver is designed to operate at 2.4 GHz while being able to properly receive, process and demodulate incoming signal into raw digital data. The receiver front-end is comprised of an LNA and a super-regenerative oscillator (SRO), both merged for current reuse and lower power consumption. The front-end is followed by a simple signal conditionin...

We investigate a time-domain implementation of generalized phase-conjugated twin waves which we call conjugate data repetition. A theory based on time-domain perturbation analysis explaining the mitigation of nonlinear effects is provided, and the concept is evaluated using numerical simulations. Compared to PM-QPSK at the same channel bit rate, the single-channel transmission reach in a conven...

We report implementation of a monolithically integrated 100 Gbps dual-polarization quadrature phase shift keying (DP-QPSK) wavelength tunable coherent receiver on a 1  mm×3  mm die that consists of a tunable C-Band local oscillator with a 40 nm range, eight 30 GHz photodetectors, and two parallel 90° optical hybrids. A BER of 10(-3) with an OSNR of 7.5 dB operating at 50 Gbps NRZ-QPSK data per ...

Digital signal processing techniques are applied to maximum likelihood carrier phase synchronization for QPSK and QAM in an all-digital sampled data receiver. To achieve the flexibility required by modern Software Defined Radios (SDR’s), this task must either be performed in a DSP processor (reconfigurable software) or in an FPGA (reconfigurable hardware). This paper describes the design proces...

This paper presents new visualization techniques for 4D Quadrature-Quadrature Phase Shift Keying (QPSK), Saha’s Constant Envelope (CE) QPSK, and Cartwright’s CEQPSK in ideal bandlimited channels. The signal diagrams analyzed are: time-signal eye patterns for 4D passband signals, 2D complex trajectory diagrams of baseband signals, and time-signal eye patterns for the 1D outputs of the baseband m...

This project studies and identifies the PSK-based digital modulation scheme (BPSK, QPSK or GMSK) that gives the best BER performance in a multipath fading environment using computer simulation (MATLAB). Each PSK-based digital modulation are modeled and simulated under different channel conditions. Subsequently, a comparison study is carried out to obtain the BER performance for each PSK-based t...

In this paper, three new ultra wideband (UWB) communication systems with quadrature-phase shift keying (QPSK) impulse modulation are proposed. First, direct-sequence (DS) multiple-access scheme is applied. The second proposed system is based on time-hopping (TH) multiple-access scheme. The last proposed system applies TH multipleaccess scheme with QPSK impulse modulation and pulse position modu...