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Software-defined networks have been proposed as a viable solution to decrease the power consumption of the networking component in data center networks. Still the question remains on which scheduling algorithms are most suited to achieve this goal. We propose 4 different linear programming approaches that schedule requested traffic flows on SDN switches according to different objectives. Depending...
The rapid adoption of MPEG-DASH is testament to its core design principles that enable the client to make the informed decision relating to media encoding representations, based on network conditions, device type and preferences. Typically, the focus has mostly been on the different video quality representations rather than audio. However, for device types with small screens, the relative bandwidth...
Energy efficiency (EE) and spectral efficiency (SE) have become the key performance indicators for wireless communication systems. In this paper, EE and SE, efficiency metrics, of a digital communication system with M-QAM modulation technique are introduced. The upper bounds on the efficiency metrics over generalized-K fading channel are derived in closed form. These efficiency metrics are analyzed...
Electromagnetic spectrum is a scarce resource. Spectrum licensing is estimated to consume about 20% of cellular operators' capital expenditure (CAPEX). One important measure of spectrum use is “spectral efficiency” (SE), which is the amount of data bandwidth that a specific technology can extract from a certain amount of radio spectrum and is measured in bits per second per Hz (bps/Hz). Using data...
A large number of routing protocols for Cognitive radio networks (CRNs) have been proposed recently, each based on different design goals, and evaluated in different scenarios, under different assumptions. In our previous work, we conducted the first extensive empirical performance study of routing protocols for CRNs-Coolest Path, SAMER, and CRP — under the same realistic set of assumptions. Our study...
This paper proposes a crowdsourcing system that can provide Internet streaming media companies with the ability to assess users' Quality of Experience (QoE) when they are watching the company's online video streaming at their residences. To validate the effectiveness of the system, a resident measuring device and crowdsourcing applications on users' end device are implemented with several scenario...
We are facing an increasing interest about virtualization technologies that enable new paradigms and technical approaches like Cloud Computing, Software Defined Networks. Infrastructure Providers (InPs), managing distributed physical resources, need to perform the mapping of the requested virtual resources on the physical ones. For this purpose, they need to optimize the allocation process in order...
Application performance data accounting for resource contention and other external influences is highly coveted and extremely difficult to obtain. "Why did my application's performance change from the last time it ran?" is a question shared by application developers, program analysts, and system administrators. The answer to this question impacts nearly all programmatic and R&D efforts...
Generally, an elastic optical network (EON) under a dynamic connection (non-uniform bandwidth) set up and termination scenario leads to spectrum fragmentation, and results in higher blocking probability. To overcome this problem, a defragmentation of the spectrum can be applied by reconfiguring some or all connections in the network. However, reconfiguration can interrupt the services of the existing...
This paper presents an approach for designing continuous phase modulation (CPM) waveform with good spectral compatibility and low correlation properties. The suggested approach is to first design over-sampled polyphase code with stopband and correlation constraint, and then transform the polyphase code into CPM waveform. Applying over-sampling ensures that the resulting CPM waveform would well inherit...
Virtual Network Embedding (VNE) is a key step towards network virtualization. In this paper, we first introduce a new link interference metric for each link to quantify the interference caused by its bandwidth scarcity to accept VN requests, and then an Interference-based VNE (I-VNE) algorithm is proposed. Benefited from the new metric, I-VNE can jointly consider the temporal and spatial topology...
Vehicular ad hoc networks (VANETs) have been attracting interest for their potential roles in intelligent transport systems (ITS). In order to enable distributed ITS, there is a need to maintain some information in the vehicular networks without the support of any infrastructure such as road side units. In this paper, we propose a protocol which can store the data in VANETs by transferring data to...
Adjacent channel interference (ACI) is often not considered when spectrum sharing schemes are designed for cognitive radio networks (CRNs). In practice, it is necessary to avoid interference by deploying guard bands between two distinct receptions. However, using guard bands typically reduces spectrum efficiency. In this work, we study the impact of guard bands on spectrum efficiency under different...
Modern multicore architectures require runtime optimization techniques to address the problem of mismatches between the dynamic resource requirements of different processes and the runtime allocation. Choosing between multiple optimizations at runtime is complex due to the non-additive effects, making the adaptiveness of the machine learning techniques useful. We present a novel method, Machine Learned...
As peer to peer systems work in open environment, they are highly susceptible to malicious activities. Formation of trust relations between the peers help to minimize the impact of such attacks. This paper proposes a collaborative trust based model that works on reputation and recommendations metrics to increase trustworthiness amongst the peers for reliable services. Under this model, evaluator contacts...
The use of orthogonal waveform can offer many advantages in covert underwater acoustic communication, including improved symbol detection ability. In this paper, we derive a new orthogonal code design. The proposed code has a good autocorrelation property compared to other codes. We present some results of a lake trial to evaluate the performance of the proposed method.
Fractional Frequency Reuse (FFR) schemes are frequency allocation techniques used in cellular systems for interference mitigation and enhancing resource utilization. In this paper, analysis is presented comparing FFR and other FR algorithms under realistic network situations. Most implementations in literature considered uniform mobile placements and perfect grid models where well-defined hexagonal...
This paper presents a review of the time filtering methods to eliminate echo in antenna measurements. Two different methods, FFT and Matrix Pencil, are compared and simulated in a Planar Near Field (PNF) where other effects, such as aliasing, can happen if the simulation is not carefully carried out. Finally both time gating methods are applied to different real measurement of several antennas in...
An uplink scheduler in the Long Term Evolution (LTE) network has the objective to improve the radio resources utilization in the network. The choice of uplink scheduling procedure used impacts the throughputs of individual users, as well as the overall throughput of the cell. This paper evaluates and compares the performance of three well-known LTE uplink schedulers (namely, Maximum Throughput (MT),...
In MANETs, real-time multimedia applications make Quality of Service (QoS) support, a crucial issue regarding terms of increased throughput, reduced jitter and available bandwidth. The highly dynamic topology of the network, large variation of received signal strength at nodes and frequently varying link characteristics make QoS provisioning, a challenging task. Most of the existing routing protocols...
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