Space-time code diversity by phase rotation in multi-carrier multi-user systems

Code diversity using space-time block codes was developed for single-carrier and single-receiver systems. In this paper, the extension of code diversity by phase rotation to multi-user and multi-carrier systems is proposed and analyzed. We show that code diversity with reduced feedback is possible in this new scenario and the coding gain has a mild logarithmic decrease with the number of users and the number of sub-carriers. In addition, we develop an analytical upper bound for the average error probability whose accuracy is verified by simulation

Differential spatial modulation for high-rate transmission systems

This paper introduces a new differential spatial modulation (DSM) scheme which subsumes both the previously introduced DSM and high-rate spatial modulation (HR-SM) for wireless multiple input multiple output (MIMO) transmission. By combining the codeword design method of the HR-SM scheme with the encoding method of the DSM scheme, we develop a high-rate differential spatial modulation (HR-DSM) scheme equipped with an arbitrary number of transmit antennas that requires channel state information (CSI) neither at the transmitter nor at the receiver. The proposed approach can be applied to any equal energy signal constellations. The bit error rate (BER) performance of the proposed HR-DSM schemes is evaluated by using both theoretical upper bound and computer simulations. It is shown that for the same spectral efficiency and antenna configuration, the proposed HR-DSM outperforms the DSM in terms of bit error rate (BER) performance

Quantizers with Parameterized Distortion Measures

In many quantization problems, the distortion function is given by the Euclidean metric to measure the distance of a source sample to any given reproduction point of the quantizer. We will in this work regard distortion functions, which are additively and multiplicatively weighted for each reproduction point resulting in a heterogeneous quantization problem, as used for example in deployment problems of sensor networks. Whereas, normally in such problems, the average distortion is minimized for given weights (parameters), we will optimize the quantization problem over all weights, i.e., we tune or control the distortion functions in our favor. For a uniform source distribution in one-dimension, we derive the unique minimizer, given as the uniform scalar quantizer with an optimal common weight. By numerical simulations, we demonstrate that this result extends to two-dimensions where asymptotically the parameter optimized quantizer is the hexagonal lattice with common weights. As an application, we will determine the optimal deployment of unmanned aerial vehicles (UAVs) to provide a wireless communication to ground terminals under a minimal communication power cost. Here, the optimal weights relate to the optimal flight heights of the UAVs

On Analog QAM Demodulation for Millimeter-Wave Communications

Recent interest in wideband multi-giga-bit-per-second wireless communications over millimeter-wave frequencies has created both new opportunities and design challenges. The realization of such technologies including multi-giga-samples-per-second data conversion and digital signal processing systems is extremely challenging. In this brief, we propose a fully analog QAM demodulator as a step toward eliminating the power-hungry and ultra-high speed mixed-signal components (e.g., analog-to-digital converter). The proposed low-complexity, low-overhead solution is shown to be robust against analog processing errors

On Analog QAM Demodulation for Millimeter-Wave Communications

Recent interest in wideband multi-giga-bit-per-second wireless communications over millimeter-wave frequencies has created both new opportunities and design challenges. The realization of such technologies including multi-giga-samples-per-second data conversion and digital signal processing systems is extremely challenging. In this brief, we propose a fully analog QAM demodulator as a step toward eliminating the power-hungry and ultra-high speed mixed-signal components (e.g., analog-to-digital converter). The proposed low-complexity, low-overhead solution is shown to be robust against analog processing errors