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Layered Division Multiplexing (LDM) is a novel non-orthogonal multiplexing access (NOMA) technique, based on power allocation techniques, which has been recently included in the ATSC 3.0 Digital Television Terrestrial (DTT) standard. In the recent literature, the LDM capabilities have been studied just for the two layered case, mainly when one of the layers is targeting mobile/indoor services and...
In this paper, we analyze a shared access network with one primary device and randomly distributed smart objects with secondary priority. Assuming random traffic at the primary device and saturated queues at the smart objects with secondary priority, an access protocol is employed to adjust the random access probabilities of the smart objects depending on the congestion level of the primary. We characterize...
Unlike traditional cellular networks, the multi-tier architecture of 5G networks supports Device-to-Device (D2D) communication, which allows devices to communicate with each other autonomously. Consequently, D2D-enabled Internet of Things (IoT) promise to provide higher bandwidth through frequency spectrum sharing. However, energy efficient operation of the network becomes a major challenge due to...
For LTE-A TDD systems supporting DL heavy asymmetry traffic, the number of downlink (DL) subframes are much higher than that of uplink (UL) subframes. The HARQ feedbacks of multiple DL tranport blocks may be transmitted in one UL subframe. Time-bundling is a technique proposed to reduce the HARQ signaling overhead by combining multiple ACK/NACKs into one using ‘AND’ operation. In this paper, we propose...
Transmission at 60GHz millimetre wavelengths is often prone to strong signal attenuations and disconnections when-ever objects greater than the wavelength of the propagating signal interrupts the line-of-sight. When this occurs, the network becomes unreliable and its performance is severely affected by unexpected and frequent disconnections, loss of data, retransmissions, waste resources and increased...
Due to the directionality of transmissions in millimeter wave (mm-wave) networks, wireless stations are usually unable to overhear when other stations access the channel. This makes it hard to design efficient distributed beam coordination and scheduling mechanisms. At the same time, centralized schemes only perform well in relatively simple, static scenarios. In practical settings where links have...
This paper studies the problem of optimal power allocation towards maximizing the throughput of point-to-point wireless communication systems with energy harvesting. A novel energy-transferring approach is proposed to analyze the throughput maximization problem with causality constraints, in which we study the transfer energy rather than the water level widely used in the existing literature. The...
We consider a two-user energy harvesting broadcast channel, and characterize the delay minimal transmission policies that minimize the total delay experienced by the data packets in the system. We consider a continuous time system where the delay experienced by each bit is given by the time spent by the bit in the queue waiting to be transmitted to its receiver. We consider the case where all data...
This work explores the benefits in terms of energy efficiency that can be provided by device-to- device (D2D) communications in cellular systems. Analyzing a large cellular network using stochastic geometry, considering Nakagami fading and realistic system parameters, we explore the reduction that can be achieved in network power consumption, and the impact this reduction has on the performance of...
Device-to-device (D2D) communication underlaid with cellular networks is a new paradigm, proposed to enhance the performance of cellular networks. By allowing a pair of D2D users to communicate directly and share the same spectral resources with the cellular users, D2D communication can achieve higher spectral efficiency, improve the energy efficiency, and lower the traffic delay. In this paper, transmission...
Network coding offers a promising platform for multicast transmission to improve the throughput. However, the users may not collect a full set of the encoded packets to recover the useful information because of its block processing property, leading to the low throughput under wireless fading channel. While the schemes that using feedback from all the receivers to cover the problem above always causes...
We study the precoding for the high-rank MIMO in the LTE-A Pro systems. Unlike the low-rank precoding, layer mapping has a relatively large impact on the performance for high-rank precoding. First, we construct a model on the relationship between layer mapping and precoding. Then we derive the system throughput with the resulting model, so that the performance of the layer mapping and precoding can...
In this paper, we propose a cognitive Go-Back-N Hybrid Automatic Repeat reQuest (CGBN-HARQ) scheme for a cognitive radio (CR) system to opportunistically transmit data over a primary radio (PR) channel. We model the activity of PR users (PRUs) occupying the PR channel as a Markov chain with two states: `ON' and `OFF'. In order to use the PR channel, the CR system first senses the availability/unavailability...
Recent advances in Unmanned Aerial Vehicles (UAVs) have enabled a myriad of new applications in many different domains from personal entertainment to process and infrastructure online monitoring in large industrial sites, among other. Our work focuses on how one can use several small UAVs collaboratively to provide extended reach to an online video monitoring system. We demonstrate how a TDMA overlay...
It has been well-established that Device-to-device (D2D) communication underlying cellular networks can improve network radio resource efficiency and provide higher transmission data rates to devices in proximity. In this work, we propose a cooperative system model. Three relay selection schemes are compared under such model. The Distance-based Relay Selection considers only distance for optimal relay...
In this paper, decentralized heuristic access policies are designed for two secondary users (SUs) in an underlay cognitive radio network in which the PU employs Type-I Hybrid ARQ. Exploiting the redundancy in PU retransmissions, each SU receiver applies interference cancellation (IC) to remove a successfully decoded PU message in the subsequent PU retransmissions. There is no central control unit...
Energy harvesting point-to-point communications are considered. The transmitter harvests energy from the environment and stores it in a finite battery. It is assumed that the transmitter has always data to transmit and the harvested energy is used exclusively for data transmission. As in practical scenarios prior knowledge about the energy harvesting process might not be available, we assume that...
We consider an energy harvesting two-way channel with decoding costs. In this system, each node spends energy to transmit data to the other user, and also to decode data coming from the other user; that is, each user divides its harvested energy for transmission and reception. The power needed for decoding the incoming data is a function of the incoming data rate. We determine the optimal offline...
In this work, the stability region of the broadcast channel (BC) is explored, where the receiver, for which the packets need to be kept secret from the other receiver has full-duplex (FD) capability. The effect of self-interference on the stability region has also been investigated. In particular, the stability region is characterized under two types of decoding schemes: (a) both the receivers perform...
Mostly real time applications want rapid data transmission in the network. The performance can be ensured by mechanisms which gives performance by shaping and policing of packet traffic. Further improve the performance of the network by fair allocation of resources. Many congestion control techniques provide good fairness and throughput, which decreases the loss of packet. We have analyzed the strength...
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