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Heterogeneous cloud radio access network (H-CRAN) is proposed as a cost-effective paradigm to meet the ever-increasing mobile data traffic demand, where the key idea is applying cloud computing technologies in a heterogeneous network (HetNet) to improve both spectral and energy efficiencies of the cellular system. In this paper, we investigate how to provide as many as possible users with QoS-guaranteed...
Underwater acoustic communication systems use a bandwidth that is comparable to the center frequency of the signal and qualify as broadband in a relative sense. And underwater acoustic channels are time-varying and multipath channels, giving rise to serious inter-symbol interference (ISI), inter-carrier interference (ICI) and time-domain telescopic changes in the underwater acoustic OFDM system. In...
Cloud radio access networks (C-RAN) has been regarded as a promising solution to the next generation communication system, but the massive fronthaul bandwidth required to aggregate baseband samples from remote radio head (RRH) to the baseband unit (BBU) pool has a significant impact on the performance of C-RAN. Existing baseband compression algorithms can hardly solve this problem. So, in this paper...
We consider a single cell wireless uplink in which randomly arriving devices transmit their payload to a receiver. Given SNR per user, payload size per device, a fixed latency constraint T, total available bandwidth W, i.e., total symbol resources is given by N = TW. The total bandwidth W is evenly partitioned into B bins. Each time slot of duration T is split into a maximum number of retransmission...
Visible light communication is an emerging field in indoor wireless connection, and it is a candidate technique to provide high-speed data transmission. In this paper, we propose a joint optimal waveform design system to support multiple users. In this system, transmitted waveforms and minimum mean squared error filters are jointly optimized to minimize the inter-symbol interference and multiple access...
In this paper, we investigate the energy efficiency (EE) performance of optimal scheduling strategies in ultradense networks (UDNs). We consider a network deployment of base stations (BSs) based on a homogeneous Poisson Point Process (PPP), and assume users requests, modeled according to a space-time homogeneous Point Process (STPP), are to be served within a given service time. The objective is to...
To face the challenges of the new era of heterogeneous networks, mobile satellite systems need to provide an increased level of flexibility. As a consequence, a more effective use of the available resources and the exploitation of interference mitigation techniques are considered necessary to tackle the issue. The limits of a traditional configuration are even more noticeable in specific areas of...
High throughput satellites have proven to be an excellent solution to provide Internet services to white spots or to complement other existing infrastructures. With the use of multi-beam antennas, the same frequency may be reused dozens of times across a single satellite coverage area, increasing the system capacity and profitability. Legacy frequency reuse patterns such as uncoordinated 4-color scheme...
Heterogeneous cellular network (HCN), which generally consists of small cell base stations (SBSs) and macro base stations (MBSs), is proposed as a promising scheme to improve the capacity of the cellular network. However, huge energy consumption by the densely deployed SBSs arises as a challenging problem that should be addressed properly to fulfill the potential of HCNs. In this paper, we aim to...
An interference monitoring station is presented which detects, characterises and logs interference events. The system operates autonomously and continuously over multiple global navigation satellite system (GNSS) bands. With a bandwidth of up to 80 MHz, input resolution of 8 bit an overall data rate of approximately 1.3 Gbit/s can be supported. The interference detection is carried out in real-time,...
Genetic Algorithms (GAs) have been shown to be a very effective optimisation tool on a wide variety of problems. However, they are not without their drawbacks. GAs require time to run, and evolve a bespoke solution to the desired problem in real time. This requirement can prove to be prohibitive in a high-frequency dynamic environment where on-line training time is limited. Neural Networks (NNs) on...
A heterogeneous system is based on an integration of different types of networks. In this paper, a system based on LTE and WIMAX for the Virtual University of Senegal is presented. It aims to study and optimize the system performance considering the Signal to Interference plus Noise Ratio (SINR), the blocking probability, user communications, and mobility loss. A Markov chain was used to assess and...
Larger share of total energy consumed by mobile network operators (MNOs) is wasted to ensure seamless coverage. Three to six MNOs covering the same geographical area results in even more energy waste. Division of scarce resource, i.e., spectrum into small chunks also deteriorates the overall performance. With exponential growth of the traffic and insignificant marginal revenue, it is time for the...
This paper focuses on the optimization of routing and interference-aware resource allocation for a wireless backhaul network, focusing on the end-to-end delay minimization. We adopt a convex optimization formulation, which allows the decomposition of the problem, separating the network-plane and the communications-plane, and also allows an easy interpretation of results. We integrate the solution...
With growing data demand and the current dearth of spectrum, mobile operators are looking for new frequency bands to satisfy data-hungry users. One promising avenue of expansion is TV white spaces, which are currently available to secondary users as long as they do not interfere with primary (i.e., incumbent) users. In this work, we explore the benefits of offloading cellular traffic onto TV white...
One of the goals of 5G wireless systems stated by the NGMN alliance is to provide moderate rates (50+ Mbps) everywhere and with very high reliability. We term this service Ultra-Reliable Ubiquitous-Rate Communication (UR2C). This paper investigates the role of frequency reuse in supporting UR2C in the downlink. To this end, two frequency reuse schemes are considered: user-specific frequency reuse...
Priority queue-based techniques improve spectrum efficiency by allocating the underutilized spectral bands (holes) of primary users to secondary users in Cognitive Radio Networks (CRN). This article proposes a Distributed Precedence Queuing scheme for Efficient Spectrum Management (DPQESM) in CRNs. The proposed method classifies the available channels into periodic and aperiodic based on the state...
In this paper, flexible frequency division duplex (FDD) and time division duplex (TDD) schemes are considered in FDD spectrum. With FDD spectrum, there is a paired uplink (UL) carrier with each downlink (DL) carrier, each carrier with the same bandwidth. Because equal resources are provisioned for the DL and UL, FDD spectrum is not well suited for asymmetric DL/UL traffic. While the FDD UL-paired...
Cloud radio access network (C-RAN) is introduced as a promising network architecture to meet the ever-increasing mobile data traffic. Baseband processing is decoupled from the remote radio head (RRH) and centralized in a common resource pool in C-RAN architecture, which enables efficient resource allocation. In this paper, we study the user association problem in order to better utilize wireless resources...
Li-Fi or Light Fidelity is a concept more often considered related to Wi-Fi which is Wireless Fidelity, but is far more dissimilar right from the core concept. Li-Fi as opposed to Radio waves in Wi-Fi uses Visible Light for bringing about the communication between two devices. This paper throws light on how Light (VLC) is a feasible solution to the existing problems of radio waves with some useful...
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