Device-to-Device (D2D) communications have been highlighted as one of the promising solutions to enhance spectrum utilization of LTE-Advanced networks. In this paper, we consider a D2D transmitter cooperating with a cellular network by acting as a relay to serve one of the cellular users. We consider the case in which the D2D transmitter is equipped with an energy harvesting capability. We

This paper studies the problem of cooperative communications in cognitive radio networks where the secondary user is equipped with finite length relaying queue as well as finite length battery queue. The major hurdle towards fully characterizing the stable throughput region stems from the sheer complexity associated with solving the two-dimensional Markov Chain (MC) model for both finite queues

In this paper, we study the general multiple input multiple output (MIMO) multi-way relay channel, i.e., MIMO Y channel, with common and private messages. In this channel, K users exchange messages through a common relay. Each user transmits a private message to each user in addition to a common message to all the other users. The i th user and the relay are equipped with Mi and N antennas

We characterize time and power allocations to optimize the sum-throughput of a Wireless Powered Communication Network (WPCN) with Non-Orthogonal Multiple Access (NOMA). In our setup, an Energy Rich (ER) source broadcasts wireless energy to several devices, which use it to simultaneously transmit data to an Access Point (AP) on the uplink. Differently from most prior works, in this paper we

In this paper, we characterize the stability region of cognitive radio networks with a dedicated relay node. In particular, we study this system under two different MAC protocols: perfect sensing and random access. In the perfect sensing protocol, the relay node and the secondary user access the medium only when the primary user is idle. In the random access protocol, both the relay and the

We consider the problem of optimizing the performance of a cooperative cognitive radio user subject to constraints on the quality-of-service (QoS) of the primary user (PU). In particular, we design the probabilistic admission control parameter of the PU packets in the secondary user (SU) relaying queue and the randomized service parameter at the SU under non-work-conserving (non-WC) and WC

Machine-to-Machine (M2M) has become a generally used term owing to the concept of the Internet of Things (IOT). M2M communications have numerous areas of implementation such as medicine, transportation, environmental monitoring, and smart grids. As the field of its implementation extends, the number of M2M equipment are projected to grow proportionally in the upcoming few years. Current cellular

In this paper, a cognitive radio system is studied in which the secondary user (SU) leverages the primary user (PU) channel quality indicator feedback (CQI) and the PU automatic repeat request (ARQ). The SU randomly accesses the PU channel with access probabilities based on its spectrum sensing outcome and the PU feedbacks. The SU's access probabilities are selected though an optimization problem

In this paper, we introduce the novel concept of cost-effective mobile health care which leverages the multiple wireless interfaces onboard most mobile phones today. First, we study the problem of uploading medical data using the 'least cost' radio interface. Toward this objective, we propose the wireless interface selection algorithm (WISA) which decides the wireless interface yielding the least

The ability of physical layer relay caching to increase the degrees of freedom (DoF) of a single cell was recently illustrated. In this paper, we extend this result to the case of multiple cells in which a caching relay is shared among multiple non-cooperative base stations (BSs). In particular, we show that a large DoF gain can be achieved by exploiting the benefits of having a shared relay that