Abstract
In this paper, we consider device-to-device (D2D) communication that is underlaid in a multi-cell massive multiple-input multiple-output (MIMO) system and propose a new framework for power control and pilot allocation. In this scheme, the cellular users (CUs) in each cell get orthogonal pilots which are reused with reuse factor one across cells, while all the D2D pairs share another set of orthogonal pilots. We derive a closed-form capacity lower bound for the CUs with different receive processing schemes. In addition, we derive a capacity lower bound for the D2D receivers and a closed-form approximation of it. We provide power control algorithms to maximize the minimum spectral efficiency (SE) and maximize the product of the signal-to-interference-plus-noise ratios in the network. Different from prior works, in our proposed power control schemes, we consider joint pilot and data transmission optimization. Finally, we provide a numerical evaluation where we compare our proposed power control schemes with the maximum transmit power case and the case of conventional multi-cell massive MIMO without D2D communication. Based on the provided results, we conclude that our proposed scheme increases the sum SE of multi-cell massive MIMO networks.
Highlights
Device-to-device (D2D) underlay communication and massive multiple-input multiple-output (MIMO) are two new promising technologies in wireless communication that will appear in 5G networks [2]
We have presented a framework for pilot allocation for multi-cell massive MIMO systems with underlaid D2D communication
We proposed different power control schemes for the considered system model and solved max-min fairness and max product signalto-interference-plus-noise ratios (SINRs) optimization problems for MR and ZF processing at the base stations (BS). We considered both data power control and joint pilot and data power control for both optimization objectives
Summary
Device-to-device (D2D) underlay communication and massive multiple-input multiple-output (MIMO) are two new promising technologies in wireless communication that will appear in 5G networks [2]. A detailed analysis is provided for the case of perfect channel state information (CSI), in which they study the asymptotic and non-asymptotic spectral efficiency (SE) of CUs and D2D pairs They perform channel estimation based on an orthogonal training scheme that allocates orthogonal pilots to CUs and a limited number of D2D pairs nearest to the location of the BS in their cell. In [20], the authors consider a multi-cell massive MIMO UL D2D underlay model and consider the spatial location of BSs and D2D transmitters follow two independent homogeneous Poisson point process They derive exact expressions of the SEs for cellular and D2D communication which are not in closed form. This paper does not consider channel estimation and pilot transmission and they only apply a simple open-loop power control scheme
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