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In this paper, we have proposed secondary user (SU) resource assignment scheme for a multi-hop cognitive radio network. In Multi-hop networks, since each link has different SNR because of their different distance between the stations and some other circumstance, it degrades the end-to-end throughput. To overcome this problem, we have proposed to give a channel priority in each link based on the link...
We present a new iterative mathematical model for calculating the average bandwidth assigned to traffic flows using a WRR scheduler in IP based NGN networks. The bandwidth assignment estimation is based on the average packet length, link speed and the arrival rate. We prove the model outcome with examples and simulation results using NS2 simulator.
We present an algorithm for multi-physics simulation of charged particles in electrokinetic flows. It includes a coupled simulation of charged rigid particles in fluid flows in an electric field. The parallel simulation algorithm is implemented in the waLBerla software framework. For solving the partial differential equation that models the electric potential, a cell-centered multigrid algorithm has...
In modern communication systems, the signal splitter and combiner called BALUN (BALance to UNbalance) is required to interface a single ended device with a differential ended device. Most active BALUN deploy passive elements which cannot be tuned and requires large area in the integrated circuit. Though there is the controllable BALUN based on BiCMOS CCCII, the implementing circuit is quite large...
We consider a multirate access tree network accommodating K service-classes of Poisson traffic, and focus on the determination of derivatives of Call Blocking Probabilities (CBP) with respect to offered traffic-load of any service-class. Based on the derivatives, we further show how we can successfully approximate CBP for small variations of offered traffic-load.
Metaverses provide a framework for developing distributed 3D Internet applications where users gain presence through the proxy of an avatar. They offer much of the engagement of online 3D games but support heterogeneous applications. From the network perspective metaverses are similar to games in that timeliness is important but differ in that their traffic is less regular and requires more bandwidth...
The Disturbance Observer (DOB) is widely used in many robust control applications such as robotics and industrial automation due to its simplicity and efficiency. The DOB estimates and compensates the system disturbances by using an inner-feedback loop in the range of its bandwidth. It includes the inverse of the nominal system model and a low pass filter (LPF) which determines the bandwidth of the...
A silicon-compatible, broadband, millimeter wave Marchand balun operating at a center frequency of 65 GHz is presented. This balun is asymmetrical and broadside-coupled and exhibits excellent performance over a 30–90 GHz frequency range. The gain imbalance is −1.6 dB at 30 GHz, and +0.6 dB at 90 GHz, with a phase imbalance of ± 5.2 degrees, respectively. The balun exhibits good insertion loss and...
As audiovisual communications services become the dominant traffic source in the Future Internet, their stable coexistence and their fairness towards background traffic is an active research topic. The Internet implements flow multiplexing in a decentralized fashion via congestion control. Audiovisual media streams, however, are classified as inelastic traffic flows that do not allow rate control...
With the advances in mobile technologies, smart mobile computing devices have become increasingly affordable and powerful, leading to a significant growth in both the number of advanced mobile users and their bandwidth demands. Moreover multimedia streaming to these high-end mobile devices has become widespread. However, multimedia applications are known to be resource-hungry and in order to cope...
A directional coupler with arbitrary output amplitude and phase distributions is proposed. Design equations and experimental results are presented and compared with numerical simulations. During the presentation, the use of the coupler as a building block for a Butler matrix will be shown. The proposed coupler achieves a significant size reduction over conventional couplers. It is five times smaller...
The widespread deployment of varying networking technologies, coupled with the exponential increase in end-user data demand, have led to the proliferation of multi-homed or multi-interface enabled devices. To date, these interfaces are mainly utilized one at a time based on network availability, cost, and user-choice. While researchers have focused on simultaneously leveraging these interfaces by...
Public administrations assign the spectrum bands to wireless operators by a license scheme. Generally, operators gain spectrum licenses by bidding for them in public auction processes (primary market). The increasing demand of spectrum and the existence of spectrum holes have revealed the inefficiency of this mechanism. One practical and economically feasible way to solve this inefficiency is to allow...
In this paper we present a correlation based error estimation technique using a residual test signal for the linearization of multibit feedback DACs of lowpass and bandpass Delta-Sigma analog-to-digital converters. Using residual test signal insertion allows operating in background with only limited loss in peak performance during test. Opposed to dynamic element matching techniques, which are limited...
Mismatch of components in a time-interleaved ADC (TIADC) is a major problem which can significantly degrade the performance, even with a 0.5\% mismatch. This paper describes a new technique which uses checksums for diagnosing the mismatch of components among sub-ADCs in a TIADC. In our checksum formulation, a transition matrix is used to represent the transition relationship between the current state...
With the advancements in semiconductor chip manufacturing technology, it has been possible to put the various components of a system with more than one hundred processors, on a single chip. Network on chip (NoC) has been used as an effective communication platform for such systems. Due to the delays induced by routers and other equipment employed in NoC, the performance of communications for chips...
In this paper, we present a design method of bandwidth enhancement for Distributed Amplifiers (DAs), by using filter structures. Instead of using classical constant-k section in conventional DA we use both Chebyshev and Butterworth filters in both transmission lines in order to form respectively the gate and drain transmission lines of the new DA. In order to improve the bandwidth, the filter structure...
Network bandwidth is considered a valuable resource in most computer systems. To precisely detect network anomalies (with a few false alarms), an intrusion detection system requires reliable methods. A potential solution in predicting network bandwidth usage is using a time-series model with a threshold. This paper proposes a network anomaly detection technique based on SARIMA, a time-series model,...
It is widely known that signals with sparse spectrums may be properly acquired when using specific sub-Nyquist sampling frequencies. This alleviates the sampling requirements in advanced acquisition systems, such as the direct-sampling solution to the software-defined radio paradigm. Unfortunately, beyond the theorem of bandpass sampling, analytical expressions for these valid sub-sampling rates are...
Weighted Fair Queuing (WFQ) is a packet scheduling technique allowing guaranteed bandwidth services. However, it is very difficult to implement the WFQ for a lot of queues, because the amount of required calculations for WFQ is proportional to the number of queues. Therefore we proposed the simplified WFQ (SWFQ) mechanism which can support a huge number of queues with guaranteeing the provisioned...
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