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Data center infrastructure design has recently been receiving significant research interest both from academia and industry, in no small part due to the growing importance of data centers in supporting and sustaining the rapidly growing web-based applications including search (e.g., Google, Bing), video content hosting and distribution (e.g., YouTube, NetFlix), social networking (e.g., facebook, twitter),...
In orthogonal frequency division multiplexing (OFDM) relay system, subcarrier mapping at the relay has been shown to substantially improve the performance evidently. In this paper, we investigate the performance analysis of dual-hop OFDM relay systems with subcarrier mapping over Nakagami-m fading channels. A closed-form expression of outage probabilty is derived for Amplify-and-Forward OFDM Relay...
In this paper, a new cross layer design of MAC and Routing protocol for OFDMA-based Multi-hop Ad-hoc Networks is proposed. In wireless network, when a route is established, the radio resource allocation problems at MAC layer may decrease the end to end performance proportionally with the length of each route. The contention at MAC layer may causes routing protocol to respond by finding new routes...
By exploiting the sparsity of the channel impulse response (CIR), compressive channel sensing methods are capable of recovering the channel state information with overwhelming probability, given that the sensing matrix holds the restricted isometry property (RIP). To this end, random pilot patterns are often assumed to ensure the RIP of the sensing matrix. In practical orthogonal frequency division...
In this paper, we analyze the performance of decode-and-forward (DF) multiple-input multiple-output (MIMO) relay networks in which the source and relay use the same orthogonal space-time block code (OSTBC) for transmission whereas the relay and destination use maximum — ratio-combining (MRC) for reception. In particular, by assuming that the DF relay operates over Nakagami-m fading channels in the...
Ultra wideband (UWB) system using multi antennas and time reversal (TR) possesses capability of multiuser system. Each user with long channel response signature is exploited for multiple access problems. If UWB channels are independent, the multi antenna UWB system shows both capacity and diversity gain. However, due to correlation between antennas, the performance of system degrades. In this paper,...
Nowadays, networks are large heterogeneous systems in which efficient and effective support for multi-access technologies is imperative. The enhanced performance and availability of various technologies like WiFi, WiMax, and UMTS have motivated network users towards increased utilization. In these heterogeneous networks, a seamless connectivity with acceptable level of quality should be maintained...
Vehicles in different types such as bus, truck, car, motorbike may differently affect traffic state. This paper proposes a notable model to dynamically identify the effect of different vehicle types on traffic state estimation. In addition, a novel traffic state quantification model considering these effects was proposed. Here, traffic states can be quantified into levels using the GPS data reported...
Along with the development of bandwidth consuming services, fiber optic is being widely used, especially in the metro core networks. Many solutions have been proposed for designing optical network topology. However these solutions neither focus on all-optical network nor fault tolerance issue. This paper proposes a solution for designing physical topology of optical metro core networks with the objective...
In this paper, we investigate the performance of a single-input and multiple-output cognitive radio network over Rayleigh fading. In particular, we assume that secondary transmitter (SU-Tx) and primary transmitter (PU-Tx) are equipped with a single antenna while secondary receiver (SU-Rx) and primary receiver (PU-Rx) have multiple antennas. Additionally, the SU-Tx transmit power is subject to outage...
One possible way to define the end of lifetime for a Wireless Sensor Network (WSN) is to set a threshold for the number of disconnections among the sensor nodes so that above this level the WSN becomes unable to provide the quality of services required by the users or even totally loses its ability to provide any service at all. Disconnections isolate sensors or group of sensors which cannot deliver...
This paper presents the frequency reconfigurable antenna that can be applied either in LTE (2.6 GHz) or WiMAX (3.5 GHz) applications. This antenna is designed with a combination of an aperture coupled as the feeding technique and stacked patch technology or known as a Frequency Reconfigurable Stacked Patch Microstrip Antenna (FRSPMA). It consists of three substrates layers where all the layers are...
Due to the increasing demand for higher data rates by mobile users, the deployment of femtocells under macro coverage has been adopted by 3GPP LTE-Advanced systems as one of the main proposals to enhance the network performance in the respects of coverage and capacity improvement especially for indoor users. However the random deployment of femtocells raise the issue of interference between macrocell...
Device-to-Device (D2D) communication will become an important technology in future wireless networks with increasing demand for local communication services. In particular, enabling D2D links in a cellular network presents a challenge in radio resource management due to the interference between cellular and D2D terminals. Many research works have considered cellular users as the primary and proposed...
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