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In this paper, a simple and accurate estimation on performance of the original IEEE 802.11 distributed coordination function (DCF) is presented. The performances obtained from the Bianchi’s analytical model of the IEEE 802.11 DCF are compensated by means of (1) the number of consecutive successful transmissions and (2) the deferred slot time. The compensated performances including throughput, packet...
This paper presents an efficient resource allocation approach for outband device-to-device communication within cellular networks. The proposed method aims to maximize bandwidth resource utilization and simplify system protocols, greatly optimizing throughput by minimizing the number of blocked connections and increasing the ease of operation. Using this method, bandwidth resources can be effectively...
Assuming the use of Hybrid ARQ, we propose to find out the best modulation and coding scheme at each retransmission round when partially outdated channel state information is available at the transmitter. Our analysis and proposed algorithm are based on Markov decision processes.
The presented paper demonstrates the use of discrete event simulation for throughput assessment of a temporarily single-track tramline in the traffic terminal Ostrava-Svinov. Under normal conditions, the tramline is double-track. However, due to the reconstruction of Svinov Bridges, that are part of this traffic terminal, between 2011 and 2012, it was operated on a single track. This action had an...
Network-on-Chip (NoC) is an emerging solution for interconnect problems for both ASICs and FPGAs nowadays. In this paper, we deliver a comparative review between ASIC-based and FPGA-based NoCs. An exploration of design tradeoffs for different NoC design parameters is also given. We also propose an evaluation methodology and design recommendations for various design parameters for both ASIC and FPGA...
In this paper, we propose a Group-Oriented QoS-Enhanced proportional fair (GQPF) scheduling algorithm, which aims at maximizing QoS throughput while still retaining fairness as well as maximizing system throughput in downlink OFDMA networks. GQPF proposes a Group-Oriented QoS-enhanced PF-based utility function for multi-channel OFDMA networks. We demonstrate via extensive simulation results, that...
The aim of this paper is to present a model for the throughput of the 1-persistent CSMA protocol in underwater networks, where the typically large propagation delay with respect to the packet transmission time requires to take into account the spatial distribution of the nodes. Our model is developed based on the analysis carried out in [1] for the non-persistent CSMA protocol. Our results show that...
Named Data Networking (NDN) is currently a hot research topic in the field of network architecture, and its transport control mechanism is one of the key technologies needed to be studied. Since the transport in NDN network has the characteristic of multi-source, the implicit congestion detection mechanism of the traditional TCP protocol is no longer suitable for the NDN network. In this paper, we...
Network simulations mostly focus on protocol observation, development, and prediction. However, newly developed protocol will take time to become standard and be implemented on network devices. A faster way of network improvement is to optimize existing network card parameters, because they are generic and protocol-independent. In this paper, we propose mathematical models to represent network card...
Vehicle to grid technologies (V2G) utilize the batteries in electric vehicles (EV) to provide ancillary services to the electric power grid. In order to maintain a 60-hertz frequency in the electric grid, there exists a wholesale market for frequency regulation (FR), a specific type of ancillary service. This paper examines V2G technology for providing FR, while focusing on the effect FR service has...
Fab operations have evolved to full automation along with advancements of automation technologies in material handling, inspection and manufacturing execution and management. A school of practitioners and re-searchers have been arguing that there need only two levels in short-interval production control of a fully automated fab: wafer release (WR) on the top and real time dispatching in the bottom...
ARQ (Automatic Repeat Request) is an error control protocol. Packet combining (PC) scheme is an extended ARQ, and Aggressive Packet Combining (APC) scheme is another error correction scheme. In PC & APC scheme two & three copies of the packet are send in all channel condition respectively. The wireless channel for packet transmission is not only random but time varying. In this paper we investigate...
Spectrum access by an unlicensed secondary user (SU) in a cognitive radio network (CRN) is challenging due to the dynamic nature of spectrum availability and possibility of collisions with the primary user (PU). SU uses a scheme where SU's packets are interleaved with periodic sensing to detect PU's return. To utilize spectrum efficiently, this paper proposes an opportunistic spectrum approach with...
Carrier aggregation has been introduced by 3rd Generation Partnership project (3GPP) in order to meet the IMT-Advanced requirements. Using carrier aggregation, multiple component carriers with a different bandwidth, dispersed within intra or inter bands can be simultaneously utilised to provide higher data rates, better coverage and lower latency resulting a better user experience. However, carrier...
The performance of MAC layer protocol in wireless network is the main factor that determines the efficiency in sharing and utilizing the limited bandwidth resources. In this paper, a practicable distributed backoff algorithm, which is named Adaptive Contention Window Backoff (ACWB) for IEEE 802.11 wireless LAN is presented. ACWB algorithm tunes the Contention Window size in a distributed manner at...
In this paper, we investigate the performance of HWMP, OLSR and DD protocols in a VANET crossroad scenario. The mobility patterns of vehicles are generated by means of SUMO (Simulation of Urban Mobility) and as communication protocol simulator is used NS3 (Network Simulator 3). For the simulations, we used IEEE 802.11p standard, Two Ray Ground Propagation Loss Model and sent multiple CBR flows over...
With the continuing development of the wireless technologies (Wi-Fi, 3G, 4G, WiMax and Bluethooth), the study of wireless multimedia transmissions has gained lately more attention. For example, the expectations of the company leaders on the growth of Wi-Fi video traffic has updated the lines of research on the standard IEEE 802.11e introduced to provide QoS (Quality of Service) to WLAN (Wireless LAN)...
In this paper we investigate the effect of Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) propagation on the Area Spectral Efficiency (ASE) and on the energy efficiency of dense small-cell networks. We show that including both LOS and NLOS propagation in the path-loss model provides a completely different picture of the behaviours of ASE and energy efficiency than what would be observed in case...
Multipliers are considered to be an important component in DSP applications like filters. Designing high-speed multipliers with low power have substantial research interest. Modified Booth Multiprecision Multiplier (MBMP) reduces the power consumption by selecting the small precision multipliers in accordance with the selection of input operands selector. The large area overhead can be reduced by...
We present a model of simple cognitive agents, called “creatures”, and their learning process, a type of “social observational learning”, that is each creature learns from the behaviour of other creatures. The creatures may experience fear and/or desire, and are capable of evaluating if a strategy has been applied successfully and of applying this strategy again with small changes to a similar but...
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