This paper considers channel estimation and system performance for the uplink of a single-cell massive multiple-input multiple-output (MIMO) system. Each receive antenna of the base station (BS) is assumed to be equipped with a pair of onebit analog-to-digital converters (ADCs) to quantize the real and imaginary part of the received signal. We first propose an approach for channel estimation that is applicable for both flat and frequency-selective fading, based on the Bussgang decomposition that reformulates the nonlinear quantizer as a linear function with identical first-and second-order statistics. The resulting channel estimator outperforms previously proposed approaches across all SNRs. We then derive closed-form expressions for the achievable rate in flat fading channels assuming low SNR and a large number of users for the maximal ratio and zero forcing receivers that takes channel estimation error due to both noise and one-bit quantization into account. The closed-form expressions in turn allow us to obtain insight into important system design issues such as optimal resource allocation, maximal sum spectral efficiency, overall energy efficiency, and number of antennas. Numerical results are presented to verify our analytical results and demonstrate the benefit of optimizing system performance accordingly.

No abstract

A new Co(II)-based MOF, {[Co(tzpa)(OH)(HO)]·DMF} (1) (Htzpa = 5-(4-(tetrazol-5-yl)phenyl)isophthalic acid), was constructed by employing a tetrazolyl-carboxyl ligand Htzpa. 1 possesses 1D tubular channels that are decorated by μ-OH groups, uncoordinated carboxylate O atoms, and open metal centers generated by the removal of coordinated water molecules, leading to high CO adsorption capacity and significantly selective capture for CO over CH and CO in the temperature range of 298-333 K. Moreover, 1 shows the chemical stability in acidic and basic aqueous solutions. Grand canonical Monte Carlo simulations identified multiple CO-philic sites in 1. In addition, the activated 1 as the heterogeneous Lewis and Brønsted acid bifunctional catalyst facilitates the chemical fixation of CO coupling with epoxides into cyclic carbonates under ambient conditions.

Seven new isostructural lanthanide metal-organic frameworks (Ln-MOFs), [Ln(Hpzbc)2(NO3)]·H2O (1-Ln, Ln = Nd(3+), Sm(3+), Eu(3+), Gd(3+), Tb(3+), Er(3+), and Yb(3+) ions, H2pzbc = 3-(1H-pyrazol-3-yl) benzoic acid), with one-dimensional (1D) channels decorated by nitrate anions and pyrazoyl groups have been constructed. 1-Ln, as revealed by structural analysis, represent uncommon microporous 3D Ln-pyrazoyl-carboxyl systems using pyrazoyl-carboxyl bifunctional ligands as bridges. The luminescent investigations show that 1-Eu is an excellent MOF-based fluorescent probe, with high sensitivity, selectivity, and simple regeneration, for environmentally relevant Fe(3+) and Cr2O7(2-) ions. 1-Eu also presents highly selective capture for CO2 over N2 and CH4 due to the multiple binding sites for CO2 molecules, which were supported by Grand Canonical Monte Carlo (GCMC) simulations.