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Neural activity in the noradrenergic locus coeruleus correlates with periods of wakefulness and arousal. However, it is unclear whether tonic or phasic activity in these neurons is necessary or sufficient to induce transitions between behavioral states and to promote long-term arousal. Using optogenetic tools in mice, we found that there is a(More)
Future mobile networks are facing with exponential data growth due to the proliferation of diverse mobile equipment and data-hungry applications. Among promising technology candidates to overcome this problem, cloud radio access network (C-RAN) has received much attention. In this paper, we investigate the design of fronthaul in C-RAN uplink by focusing on(More)
Random beamforming (RBF) is a practically favorable transmission scheme for multiuser multiantenna downlink systems since it requires only partial channel state information (CSI) at the transmitter. Under the conventional single-cell setup, RBF is known to achieve the optimal sum-capacity scaling law as the number of users goes to infinity, thanks to the(More)
The random beamforming (RBF) scheme, together with multi-user diversity based user scheduling, is able to achieve interference-free downlink transmission with only partial channel state information (CSI) at the transmitter. The impact of receive spatial diversity on RBF, however, is not fully characterized even under a single-cell setup. In this paper, we(More)
—Multiple-input multiple-output (MIMO) orthogonal-frequency division multiplexing (OFDM) multicasting system is considered. For a real-time multicast MIMO-OFDM system, we propose a non-iterative and simple linear precoding that consists of a linear sum (LS) of the corresponding channels. Through numerical results, we show that a minimum user rate of the(More)
The rate maximization for the K-user interference channels (ICs) has been investigated extensively in the literature. However, the dual problem of minimizing the error probability with given signal modulations and/or data rates of the users is less exploited. In this paper, by utilizing the additional degrees of freedom attained from the improper signaling(More)
—In this letter, the gross expenditure, revenue, and profit of a distributed antenna system (DAS) are modeled and investigated. Using stochastic geometry framework, we evaluate the communications pecuniary efficiency (PE) that is defined as a ratio of average achievable bits per expenditure. In addition, we further investigate the ratio of gross revenue(More)
In this paper, we study the performance of non-fading and Rayleigh fading ad hoc networks. We first characterize the distribution of the signal-to-interference-plus-noise ratio (SINR) through the Laplace transform of the inverted SINR for non-fading channels. Since most communication systems are interference-limited, we also consider the case of negligible(More)
—In this paper, we study the downlink performance of two important 5G network architectures, i.e. massive multiple-input multiple-output (M-MIMO) and small-cell densification. We propose a comparative modeling for the two systems, where the user and antenna/base station (BS) locations are distributed according to Poisson point processes (PPPs). We then(More)