Code Design for Non-Coherent Detection of Frame Headers in Precoded Satellite Systems

In this paper we propose a simple method for generating short-length rate-compatible codes over $\mathbb{Z}_M$ that are robust to non-coherent detection for $M$-PSK constellations. First, a greedy algorithm is used to construct a family of rotationally invariant codes for a given constellation. Then, by properly modifying such codes we obtain codes that are robust to non-coherent detection. We briefly discuss the optimality of the constructed codes for special cases of BPSK and QPSK constellations. Our method provides an upper bound for the length of optimal codes with a given desired non-coherent distance. We also derive a simple asymptotic upper bound on the frame error rate (FER) of such codes and provide the simulation results for a selected set of proposed codes. Finally, we briefly discuss the problem of designing binary codes that are robust to non-coherent detection for QPSK constellation.Comment: 11 pages, 5 figure

Constellation Design for Channels Affected by Phase Noise

In this paper we optimize constellation sets to be used for channels affected by phase noise. The main objective is to maximize the achievable mutual information of the constellation under a given power constraint. The mutual information and pragmatic mutual information of a given constellation is calculated approximately assuming that both the channel and phase noise are white. Then a simulated annealing algorithm is used to jointly optimize the constellation and the binary labeling. The performance of optimized constellations is compared with conventional constellations showing considerable gains in all system scenarios.Comment: 5 pages, 6 figures, submitted to IEEE Int. Conf. on Communications (ICC) 201

Capacity-achieving CPM schemes

The pragmatic approach to coded continuous-phase modulation (CPM) is proposed as a capacity-achieving low-complexity alternative to the serially-concatenated CPM (SC-CPM) coding scheme. In this paper, we first perform a selection of the best spectrally-efficient CPM modulations to be embedded into SC-CPM schemes. Then, we consider the pragmatic capacity (a.k.a. BICM capacity) of CPM modulations and optimize it through a careful design of the mapping between input bits and CPM waveforms. The so obtained schemes are cascaded with an outer serially-concatenated convolutional code to form a pragmatic coded-modulation system. The resulting schemes exhibit performance very close to the CPM capacity without requiring iterations between the outer decoder and the CPM demodulator. As a result, the receiver exhibits reduced complexity and increased flexibility due to the separation of the demodulation and decoding functions.Comment: Submitted to IEEE Transactions on Information Theor

Single Frequency Network Broadcasting with 5GNR Numerology

This paper investigates the possibility of using 5G New Radio (5GNR) OFDM numerology in the deployment of efficient Single Frequency Networks (SFNs) for delivering TV services to user devices. The straightforward approach in the design of the physical layer for broadcasting application is based on the adoption of OFDM signalling with very long OFDM symbol and very low sub-carrier spacing (SCS). This design choice allows to dimension the Cyclic Prefix length to eliminate ISI and ICI induced by the large delay spread with a consequent overhead reduction. The 5GNR numerology is designed for unicast transmission and Cyclic Prefix lengths are not compatible with those required for large SFN networks. In this paper we consider a general receiver based on the channel shortening principle, but in the frequency domain. The receiver consists in a bank of per tone time/frequency 2D filters, possibly followed by Maximum-Likelihood (ML) trellis processing on the shortened channel. We provide promising information theoretic bound showing that the extension of 5GNR numerology to SFN is possible with very small performance loss. Even the simplest detector architecture that does not employ trellis processing provides throughput competitive with those that can be obtained with smaller SCS. We provide end to end simulation results with practical modulation and LDPC encoder confirming that the results predicted by the bounds can be closely matched in practice

Capacity bounds for MIMO microwave backhaul links affected by phase noise

We present bounds and a closed-form high-SNR expression for the capacity of multiple-antenna systems affected by Wiener phase noise. Our results are developed for the scenario where a single oscillator drives all the radio-frequency circuitries at each transceiver (common oscillator setup), the input signal is subject to a peak-power constraint, and the channel matrix is deterministic. This scenario is relevant for line-of-sight multiple-antenna microwave backhaul links with sufficiently small antenna spacing at the transceivers. For the 2 by 2 multiple-antenna case, for a Wiener phase-noise process with standard deviation equal to 6 degrees, and at the medium/high SNR values at which microwave backhaul links operate, the upper bound reported in the paper exhibits a 3 dB gap from a lower bound obtained using 64-QAM. Furthermore, in this SNR regime the closed-form high-SNR expression is shown to be accurate.Comment: 10 pages, 2 figures, to appear in IEEE Transactions on Communication

On rate-compatible punctured turbo codes design

We propose and compare some design criteria for the search of good systematic rate-compatible punctured turbo code (RCPTC) families. The considerations presented by S. Benedetto et al. (1998) to find the "best" component encoders for turbo code construction are extended to find good rate-compatible puncturing patterns for a given interleaver length . This approach is shown to lead to codes that improve over previous ones, both in the maximum-likelihood sense (using transfer function bounds) and in the iterative decoding sense (through simulation results). To find simulation and analytical results, the coded bits are transmitted over an additive white Gaussian noise (AWGN) channel using an antipodal binary modulation. The two main applications of this technique are its use in hybrid incremental ARQ/FEC schemes and its use to achieve unequal error protection of an information sequence

Insight into the Structure of Vanadium containing Glasses: a Molecular Dynamics Study

In this manuscript, classical molecular dynamics simulations (MD) have been applied to study the short and medium range order of very complex vanadium containing glasses with the aim of improving the first microscopic picture of such materials. A rigid ionic force-field has been extended to include the V5+-O, V4+-O and Cu2+-O interatomic pair parameters and tested to reproduce structural properties of known crystal phases with quite good accuracy. Then the structure of Na2O-SiO2, CaO-MgO-Al2O3-SiO2 and Na2O-P2O5 glass compositions in which vanadium is present in the range 1-72 wt% (0.3-60 mol.%) have been fully described in terms of vanadium local structure and Qn distributions. A fairly good agreement was found with experimental data further validating our computational models and providing a computational approach that could be used and extend to investigate in detail the structural information (V-V distances, V-O-V linkages and BO/NBO) directly correlated to macroscopic properties of application interest