Abstract
Device-to-device (D2D) communications bring significant improvements of spectral efficiency by underlaying cellular networks. However, they also lead to a more deteriorative interference environment for cellular users, especially the users in severely deep fading or shadowing. In this paper, we investigate a relay-based communication scheme in cellular systems, where the D2D communications are exploited to aid the cellular downlink transmissions by acting as relay nodes with underlaying cellular networks. We modeled two-antenna infrastructure relays employed for D2D relay. The D2D transmitter is able to transmit and receive signals simultaneously over the same frequency band. Then we proposed an efficient power allocation algorithm for the base station (BS) and D2D relay to reduce the loopback interference which is inherent due to the two-antenna infrastructure in full-duplex (FD) mode. We derived the optimal power allocation problem in closed form under the independent power constraint. Simulation results show that the algorithm reduces the power consumption of D2D relay to the greatest extent and also guarantees cellular users’ minimum transmit rate. Moreover, it also outperforms the existing half-duplex (HD) relay mode in terms of achievable rate of D2D.
Highlights
Device-to-device (D2D) communication enables users in proximity to exchange information directly, without traversing to the base station (BS) or core network in two hops and has attracted increasing attention from both industrial and academic communities [1,2,3,4,5,6,7]
We show that the simulation results demonstrate high achievement transmit rate and power efficiency of the proposed FD relay-based D2D communication scheme and guarantee the rate requirement for the cellular user in the primary
It can be seen that the performance of energy efficiency does not improve with the mitigation of
Summary
Device-to-device (D2D) communication enables users in proximity to exchange information directly, without traversing to the base station (BS) or core network in two hops and has attracted increasing attention from both industrial and academic communities [1,2,3,4,5,6,7]. The existing D2D communication scheme, such as the underlaying cellular spectrum, bring more complex interference environment to cellular users which have higher priority than the D2D users, and lead to deteriorative performance on quality of service for cellular users [12,13,14]. For cellular users in the cell edge who are susceptible to suffered deep fading or shadowing, it would be unadvisable to share an allocated spectrum with D2D peers [15,16,17]. To avoid the problem mentioned above, we outline a relay-aided D2D communication scheme to fulfill the transmission gap that affects cellular users which are in the cell edge or strongly-shadowed urban environment. A D2D transmitter in our scheme is ordered to aid a cellular
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