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In this paper, we analyze the outage probability of multiple-input multiple-output cognitive cooperative radio networks (CCRNs) with multiple opportunistic amplify-and-forward relays. The CCRN applies underlay spectrum access accounting for the interference power constraint of a primary network and utilizes orthogonal space-time block coding to transmit multiple data streams across a number of antennas...
In this paper, a novel pilot extension scheme is proposed for massive MIMO uplink transmission, and its performance is evaluated analytically. Specifically, we divide the cell users into two groups, namely near users and far users, according to their distances to the service base stations. The far users are more motivated to mitigate the inter-cell interference than the near users at the price of...
The sum rate performance of distributed multiple-input multiple-output (D-MIMO) systems with Zero-Forcing (ZF) receivers over semi-correlated K fading channels involves special functions, which hinders us to further manipulations. To solve this issue, we derive the closed-form expressions of the achievable sum rate by using moment matching method, which is achieved by using a Gamma distribution to...
The existing cellular networks are being modified under the umbrella of fifth generation (5G) networks to provide high data rates with optimum coverage. Current cellular systems operating in ultra high frequency (UHF) bands suffer from severe bandwidth congestion hence 5G enabling technologies such as millimeter wave (mmWave) networks focus on significantly higher data rates. In this paper, we explore...
We study the generalized degrees of freedom (gDoF) of the block-fading noncoherent MIMO channel with asymmetric distributions of link strengths, and a coherence time of T symbol durations. We first derive the optimal signaling structure for communication over this channel, which is distinct from that for the i.i.d MIMO setting. We prove that for T = 1, the gDoF is zero for MIMO channels with arbitrary...
This paper presents a performance analysis of adaptive modulation (AM) schemes in multiple-input multiple-output (MIMO) orthogonal space-time block code (OSTBC) systems over Nakagami-M keyhole channels. We consider a constantpower variable discrete-rate AM strategy and assume that the maximum ratio combining (MRC) technique is used at the receiver. Analytical expressions for the average spectral efficiency...
Effective capacity analysis is a powerful tool to investigate the impact of physical layer designs on the link layer delay-sensitive QoS performance, which is important for real-time multimedia applications. In this paper, we rigorously analyze the effective capacities of downlink large-scale antenna systems. The main focus is to establish the fundamental effective capacity in a very-large MIMO system,...
Cross-layer design is a suitable approach that can address some of throughput challenges for future multimedia applications. In this regard, effective capacity concept offers a suitable metric to assess the implications that physical layer design may have on link layer performance. However, most reported studies in this aspect consider the case of downlink scenario for convenience multiple input multiple...
Massive MIMO (multiple-input multiple-output) provides great improvements in spectral efficiency over legacy cellular networks, by coherent combining of the signals over a large antenna array and by spatial multiplexing of many users. Since its inception, the coherent interference caused by pilot contamination has been believed to be an impairment that does not vanish, even with an unlimited number...
The application of stochastic geometry to the analysis of wireless networks is shown to be propelled by (i) a clean separation of time scales, (ii) abstraction of small-scale effects via ergodicity, and (iii) an interference model reflecting the receiver's lack of knowledge of how individual interference terms are faded. These steps render the analysis simpler and more precise, and more amenable to...
This paper presents a modified MMSE channel estimation for turbo equalization in uplink massive multiple-input multiple-output (MIMO) systems with pilot contamination. Unlike other work on channel estimation in massive MIMO systems where perfect knowledge of inter-cell large scale channel coefficients is assumed, a modified method for data-aided MMSE estimation is proposed without requiring the knowledge...
In this paper, we consider the uplink of cell-free massive MIMO systems, where a large number of distributed single antenna access points (APs) serve a much smaller number of users simultaneously via limited backhaul. For the first time, we investigate the performance of compute-and-forward (C&F) in such an ultra dense network with a realistic channel model (including fading, pathloss and shadowing)...
One of the most efficient techniques that is inevitable for the state of the art communication system in today's wireless communication is multiple-input multiple-output (MIMO) technology. MIMO provides robustness against multipath fading using spatial diversity gain, and increases data rate by spatial multiplexing gain. These gains are achieved due to the usage of several antennas. This paper presents...
This paper provides an enlightment into the pairwise error probability (PEP) of multi-antenna (MIMO) space-time code (STC) based selective decode then forward cooperative scheme considering Nakagami-m channel. We examine the pairwise error probability at the destination node, and we have formulated the closed form expression for pairwise error probability. We have achieved full diversity order in...
In this paper, we study the secrecy performance of cooperative single carrier system with the kth-best user selection scheme in Rayleigh fading channels. Assuming perfect decoding at the relay, we choose the legitimate user with the kth-best instantaneous signal-to-noise ratio (SNR) among Q users to receive the forwarded messages, which are intercepted at a passive eavesdropper simultaneously. To...
The concept of well-rounded lattices has recently found important applications in the setting of a fading single-input single-output (SISO) wiretap channel. It has been shown that, under this setup, the property of being well-rounded is critical for minimizing the eavesdropper's probability of correct decoding in lower SNR regimes. The superior performance of coset codes constructed from well-rounded...
Many aspects of lattice coding and decoding under time-varying multiple-antenna systems remain unexplored. This paper studies the achievable rates using lattice codes for the multiple-input- multiple-output (MIMO) point-to-point channel with ergodic fading and channel state information at the receiver. The proposed lattice coding scheme involves the use of decision regions that are universal for almost...
In this paper, the application of non-orthogonal multiple access (NOMA) into $K$-tier heterogeneous networks (HetNets) is investigated. A new promising transmission framework is proposed, in which massive multiple-input multiple-output (MIMO) is employed in macro cells and NOMA is adopted in small cells. For maximizing the biased average received power at mobile users, a massive MIMO and NOMA based...
We present a new accurate analysis for the downlink spectral efficiency of linear zero- forcing (ZF) beamforming over multi-user multiple- input multiple-output (MIMO) channels, experiencing composite fading effects in a multi- cell environment. In particular, Rayleigh/log- normal distribution (RLN) is proposed to model the composite fading channel. New exact expressions are derived for the downlink...
Two new non-data-aided (NDA) signal-to-noise ratio (SNR) estimators for multiple antenna systems are presented. The proposed estimators rely on higher- order moments of the received signal and employ the time-diversity of the fading channel. While one requires a priori knowledge about the number of transmit antennas, the other estimates the SNR without such knowledge. The performance of the proposed...
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