1,069 research outputs found
WLAN / WMAN Integration Architecture and Traffic Control for Voice Transmission
The popular technologies Wi-Fi and WiMAX for realization of WLAN and WMAN respectively are much
different, but they could compliment each other providing competitive wireless access for voice traffic. The article
develops the idea of WLAN/WMAN (Wi-Fi/WiMAX) integration. WiMAX is offering a backup for the traffic
overflowing from Wi-Fi cells located into the WiMAX cell. Overflow process is improved by proposed
rearrangement control algorithm applied to the Wi-Fi voice calls. There are also proposed analytical models for
system throughput evaluation and verification of the effectiveness using WMAN as a backup for WLAN overflow
traffic and the proposed call rearrangement algorithm as well
Implementation of Orthogonal Frequency Division Multiplexing with FPGA
In recent years, there have been dramatic shifts in cellular and telecommunication industries. As smartphones are dominating on the cellphone market, more and more people use these mobile devices to access internet either through third generation network or IEEE802.11 wireless local area network. Orthogonal frequency division multiplexing (OFDM) has been widely used in IEEE802.11 wireless local area network and fourth generation network. This paper will focus on the design and implementation of an Orthogonal Frequency Division Multiplexing system on field-programmable gate array (FPGA). The major components of an OFDM system include a modulator, an N-input inverse Fast Fourier Transform (IFFT), two root raised cosine filters (RRC filter), an N-input Fast Fourier Transform (FFT), and a demodulator. These components are designed by using very-high-speed integrated circuits (VHSIC) hardware description language (VHDL) under development environment of ModelSim, and then implemented onto Altera cyclone II EP2C35F672C6. The FFT accuracy is measured by comparing outputs from ModelSim to Matlab. The performance of the developed OFDM is evaluated in a wireless communication testbed
Neuro-memristive Circuits for Edge Computing: A review
The volume, veracity, variability, and velocity of data produced from the
ever-increasing network of sensors connected to Internet pose challenges for
power management, scalability, and sustainability of cloud computing
infrastructure. Increasing the data processing capability of edge computing
devices at lower power requirements can reduce several overheads for cloud
computing solutions. This paper provides the review of neuromorphic
CMOS-memristive architectures that can be integrated into edge computing
devices. We discuss why the neuromorphic architectures are useful for edge
devices and show the advantages, drawbacks and open problems in the field of
neuro-memristive circuits for edge computing
Properties of Recurrent Equations for the Full-Availability Group with BPP Traffic
The paper proposes a formal derivation of recurrent equations describing the occupancy distribution in the full-availability group with multirate Binomial-Poisson-Pascal (BPP) traffic. The paper presents an effective algorithm for determining the occupancy distribution on the basis of derived recurrent equations and for the determination of the blocking probability as well as the loss probability of calls of particular classes of traffic offered to the system. A proof of the convergence of the iterative process of estimating the average number of busy traffic sources of particular classes is also given in the paper
On Developing Facial Stress Analysis and Expression Recognition Platform
This work represents the experimental and development process of system
facial expression recognition and facial stress analysis algorithms for an
immersive digital learning platform. The system retrieves from users web camera
and evaluates it using artificial neural network (ANN) algorithms. The ANN
output signals can be used to score and improve the learning process. Adapting
an ANN to a new system can require a significant implementation effort or the
need to repeat the ANN training. There are also limitations related to the
minimum hardware required to run an ANN. To overpass these constraints, some
possible implementations of facial expression recognition and facial stress
analysis algorithms in real-time systems are presented. The implementation of
the new solution has made it possible to improve the accuracy in the
recognition of facial expressions and also to increase their response speed.
Experimental results showed that using the developed algorithms allow to detect
the heart rate with better rate in comparison with social equipment
A review of connection admission control algorithms for ATM networks
The emergence of high-speed networks such as those with ATM integrates large numbers of services with a wide range of characteristics. Admission control is a prime instrument for controlling congestion in the network. As part of connection services to an ATM system, the Connection Admission Control (CAC) algorithm decides if another call or connection can be admitted to the Broadband Network. The main task of the CAC is to ensure that the broadband resources will not saturate or overflow within a very small probability. It limits the connections and guarantees Quality of Service for the new connection. The algorithm for connection admission is crucial in determining bandwidth utilisation efficiency. With statistical multiplexing more calls can be allocated on a network link, while still maintaining the Quality of Service specified by the connection with traffic parameters and type of service.
A number of algorithms for admission control for Broadband Services with ATM Networks are described and compared for performance under different traffic loads. There is a general description of the ATM Network as an introduction. Issues to do with source distributions and traffic models are explored in Chapter 2. Chapter 3 provides an extensive presentation of the CAC algorithms for ATM Broadband Networks. The ideas about the Effective Bandwidth are reviewed in Chapter 4, and a different approach to admission control using online measurement is presented in Chapter 5. Chapter 6 has the numerical evaluation of four of the key algorithms, with simulations. Finally Chapter 7 has conclusions of the findings and explores some possibilities for further work
State-Dependent Bandwidth Sharing Policies for Wireless Multirate Loss Networks
We consider a reference cell of fixed capacity in a wireless cellular network while concentrating on next-generation network architectures. The cell accommodates new and handover calls from different service-classes. Arriving calls follow a random or quasi-random process and compete for service in the cell under two bandwidth sharing policies: 1) a probabilistic threshold (PrTH) policy or 2) the multiple fractional channel reservation (MFCR) policy. In the PrTH policy, if the number of in-service calls (new or handover) of a service-class exceeds a threshold (difference between new and handover calls), then an arriving call of the same service-class is accepted in the cell with a predefined state-dependent probability. In the MFCR policy, a real number of channels is reserved to benefit calls of certain service-classes; thus, a service priority is introduced. The cell is modeled as a multirate loss system. Under the PrTH policy, call-level performance measures are determined via accurate convolution algorithms, while under the MFCR policy, via approximate but efficient models. Furthermore, we discuss the applicability of the proposed models in 4G/5G networks. The accuracy of the proposed models is verified through simulation. Comparison against other models reveals the necessity of the new models and policies
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