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Abstract-We explore the physical-layer security for a multisource multi-relay wireless network in the presence of an eavesdropper, in which one of multiple sources is scheduled to send its message to a destination with the assistance of multiple decode-and-forward (DF) relays. One eavesdropper is considered at the receiver side, and assumed to be capable of overhearing the transmission from relays...
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...
Device-to-device (D2D) communication is one of the most promising solutions to the dramatic increase of wireless networks traffic load. In D2D communications, mobile nodes can communicate in a semi-autonomous way, with minimal or no control by the base station (BS). In this context, we address the problem of the coexistence of cellular and D2D tiers in the uplink frequencies, where a D2D source is...
Efficient transmission power control is indispensable for cellular networks. It not only provides a high energy efficiency, but also maintains reliable connections. With the emergence of 5G mobile technology, the presence of device-to-device (D2D) communications within the cellular network has stimulated research on radio resource sharing. In this paper, we consider an underlay D2D network operating...
In this paper, we investigate the performance of spatial modulation (SM) for vehicle-to- infrastructure (V2I) and vehicle-to-vehicle (V2V) communications over a generalized multiple scattering channel. This channel model provides a realistic statistical description of an intervehicular communication environment and includes as special cases the Rician, Rayleigh, and double-Rayleigh channels. We derive...
We present a multi-user multiple-input multiple-output (MIMO) cognitive radio system consisting of a secondary receiver that deploys spatial multiplexing to decode signals from multiple secondary transmitters, under the presence of primary transmissions. The secondary receiver carries out minimum mean-squared error detection to decode the secondary data streams, while it performs spectrum sensing...
This paper investigates the joint user association (UA) and user scheduling (US) for load balancing in a wireless downlink heterogeneous network by formulating a network-wide utility maximization problem. In order to efficiently solve the problem, we first approximate the original non-convex throughput function to a concave function, and demonstrate that the gap for such approximation approaches zero...
In this work, we examine the secrecy capacity region of the block-fading broadcast channel with confidential messages (BCC) when the transmitter has limited knowledge of the channel. In particular, we consider a two-user communication system where the transmitter has one common message to be transmitted to both users and one confidential message intended to only one of them. The confidential message...
Sharing the spectrum among multiple operators seems promising in millimeter wave (mmWave) systems. One explanation is the highly directional transmission in mmWave, which reduces the interference caused by one network on the other networks sharing the same resources. In this paper, we model a mmWave cellular system where an operator that primarily owns an exclusive-use license of a certain band can...
We investigate the outage and decoding-delay performances for full-duplex (FD) decode-forward (DF) relaying with backward and sliding window decoding. In our analysis, we consider a block fading channel with full channel state information (CSI) availability at receivers and with limited CSI at transmitters. For backward decoding where the destination starts decoding from the last transmission block,...
In this paper, we propose a new joint relay and jammer selection (JRJS) scheme to enhance the physical layer security for cooperative wireless networks with multiple intermediate nodes, where the decode-and-forward (DF) protocol is considered. In the proposed JRJS scheme, an ntermediate node is selected as the relay for data transmission, while the others are used to act as friendly jammers for disrupting...
In practice, wireless nodes may have different mobility and/or different scattering environment leading to disparity in coherence time and/or coherence bandwidth. Coherence diversity, as a novel source of gain, exploits fading condition disparity of different nodes to provide gain. Downlink transmission for two wireless nodes is considered in three scenarios of fading conditions disparity: in coherence...
This paper investigates a wireless-powered two-way relay network (WP-TWRN), in which two sources exchange information with the aid of one amplify-and-forward (AF) relay. Contrary to the conventional two-way relay networks, we consider the scenario that the AF relay has no embedded energy supply, and it is equipped with an energy harvesting unit and rechargeable battery. As such, it can accumulate...
In this paper, we have proposed an iterative space alternating generalized expectation maximization (SAGE) based semi-blind channel estimation technique for massive multiple-input multiple-output (MIMO) system in multi-cell pilot contamination prone scenario. The benefits of massive MIMO depend largely on the accuracy of channel state information (CSI) available at the base station (Transmitter)....
This paper investigates secrecy and connection performance for uplink transmission in a two-tier heterogeneous network with non-uniformly deployed low- power small base stations (BSs). All BSs and the eavesdropper are equipped with multiple antennas. We propose an aggregate interference approximation approach to characterize the statistics of interference generated by users associated with small BSs...
In this paper, the secrecy outage probability of cooperative cyclic prefixed single carrier (CP-SC) systems with multiple transmitters and unreliable backhaul connections is derived. The transmitters communicate with the destination in the presence of an eavesdropper over two-hop relay channels with non-identical frequency-selective fading. The existence of asymptotic limits on the secrecy outage...
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...
Caching at base stations (BSs) is a promising way to offload traffic and eliminate backhaul bottleneck in heterogeneous networks (HetNets). In this paper, we investigate the optimal content placement maximizing the successful offloading probability in a cache- enabled HetNet where a tier of multi-antenna macro BSs (MBSs) is overlaid with a tier of helpers with caches. Based on probabilistic caching...
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...
The rapid development of the Internet of Things (IoT) has brought big challenges to the traditional cellular networks such as super dense devices and deep fading channels. These new challenges will lead to a significant transmission efficiency degradation and increase the device's power consumption, especially in the uplink. A huge pressure will be also imposed to the enhanced Node B's (eNB) scheduler...
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