  Device-to-Device (D2D) communication is envisioned to be an integral
component of 5G networks, and a technique for meeting the demand for high data
rates. In a cellular network, D2D allows not only direct communication between
users, but also device relaying. In this paper, a simple instance of
device-relaying is investigated, and the impact of D2D on fairness among users
is studied. Namely, a cellular network consisting of two D2D-enabled users and
a base-station (BS) is considered. Thus, the users who want to establish
communication with the BS can act as relays for each other's signals. While
this problem is traditionally considered in the literature as a multiple-access
channel with cooperation in the uplink, and a broadcast channel with
cooperation in the downlink, we propose a different treatment of the problem as
a multi-way channel. A simple communication scheme is proposed, and is shown to
achieve significant gain in terms of fairness (measured by the symmetric rate
supported) in comparison to the aforementioned traditional treatment.
