This paper examines the number of communication modes, that is, the degrees of freedom (DoF), in a wireless line-of-sight channel comprising a small continuous linear intelligent antenna array in the near field of a large one. The framework allows for any orientations between the arrays and any positions in a two-dimensional space, assuming that the transmitting array is placed at the origin. Therefore, apart from the length of the two continuous arrays, four key parameters determine the DoF and are hence considered in the analysis: the Cartesian coordinates of the center of the receiving array and two angles that model the rotation of each array around its center. The paper starts with the calculation of thedeterministicDoF for a generic geometric setting, which extends beyond the widely studied paraxial case. Subsequently, a stochastic geometry framework is proposed to study thestatisticalDoF, as a first step towards the investigation of system-level performance in near field networks. Numerical results applied to millimeter wave networks reveal the large number of DoF provided by near-field communications and unveil key system-level insights. A comparison of the proposed method with the singular value decomposition-based method is illustrated to validate the proposed approach.

This paper investigates the signal-to-interference-plus-noise ratio (SINR)-based performance of a cellular network consisting of a fluid antenna (FA)-equipped user and small base stations (SBS), spatially distributed according to a binomial point process (BPP). By accurately capturing the shadowing effect in the calculation of received power through large-scale fading, the SINR is expressed in terms of the best selected port and the maximum average received power from the serving BS. To this end, a maximum average received power user association policy is adopted. Subsequently, by expressing the well-known Jakes' model in terms of the Gaussian copula, performance analysis in terms of coverage probability and delay coverage rate (DCR) is conducted in the presence of a single dominant interferer under correlated Nakagamim fading between the FA's ports. Numerical results demonstrate that i) by increasing the number of FA's ports, the performance improves only for the larger-sized FAs, ii) even by increasing the size of a FA with fixed number of ports, the dominant interferer poses a bound on the achieved coverage performance until eventually saturated and iii) by increasing the number of the FA's port, the enhancement in the DCR performance is more profound for the smaller amounts of the transmitted data.

A novel stochastic geometry framework is proposed in this paper to study the downlink coverage performance in a millimeter wave (mmWave) cellular network by jointly considering the polar coordinates of the Base Stations (BSs) with respect to the typical user located at the origin. Specifically, both the Euclidean and the angular distances of the BSs in a maximum power-based association policy for the user equipment (UE) are considered to account for realistic beam management considerations, which have been largely ignored in the literature, especially in the cell association phase. For completeness, two other association schemes are considered and exact-form expressions for the coverage probability are derived. Subsequently, the key role of angular distances is highlighted by defining the dominant interferer using angular distance-based criteria instead of Euclidean distance-based, and conducting a dominant interferer-based coverage probability analysis. Among others, the numerical results reveal that considering angular distance-based criteria for determining both the serving and the dominant interfering BS, can approximate the coverage performance more accurately as compared to utilizing Euclidean distance-based criteria. To the best of the authors’ knowledge, this is the first work that rigorously explores the role of angular distances in the association policy and analysis of cellular networks.