667 research outputs found
On using Multiple Quality Link Metrics with Destination Sequenced Distance Vector Protocol for Wireless Multi-Hop Networks
In this paper, we compare and analyze performance of five quality link
metrics forWireless Multi-hop Networks (WMhNs). The metrics are based on loss
probability measurements; ETX, ETT, InvETX, ML and MD, in a distance vector
routing protocol; DSDV. Among these selected metrics, we have implemented ML,
MD, InvETX and ETT in DSDV which are previously implemented with different
protocols; ML, MD, InvETX are implemented with OLSR, while ETT is implemented
in MR-LQSR. For our comparison, we have selected Throughput, Normalized Routing
Load (NRL) and End-to-End Delay (E2ED) as performance parameters. Finally, we
deduce that InvETX due to low computational burden and link asymmetry
measurement outperforms among all metrics
DSDV, DYMO, OLSR: Link Duration and Path Stability
In this paper, we evaluate and compare the impact of link duration and path
stability of routing protocols; Destination Sequence Distance vector (DSDV),
Dynamic MANET On- Demand (DYMO) and Optimized Link State Routing (OLSR) at
different number of connections and node density. In order to improve the
efficiency of selected protocols; we enhance DYMO and OLSR. Simulation and
comparison of both default and enhanced routing protocols is carried out under
the performance parameters; Packet Delivery Ratio (PDR), Average End-to End
Delay (AE2ED) and Normalized Routing Overhead (NRO). From the results, we
observe that DYMO performs better than DSDV, MOD-OLSR and OLSR in terms of PDR,
AE2ED, link duration and path stability at the cost of high value of NRO
Analysis and Modeling Experiment Performance Parameters of Routing Protocols in MANETs and VANETs
In this paper, a framework for experimental parameters in which Packet
Delivery Ratio (PDR), effect of link duration over End-to-End Delay (E2ED) and
Normalized Routing Overhead (NRO) in terms of control packets is analyzed and
modeled for Mobile Ad-Hoc NETworks (MANETs) and Vehicular Ad-Hoc NETworks
(VANETs) with the assumption that nodes (vehicles) are sparsely moving in two
different road. Moreover, this paper contributes the performance comparison of
one Proactive Routing Protocol; Destination Sequenced Distance vector (DSDV)
and two reactive protocols; DYnamic Source Routing (DSR) and DYnamic MANET
On-Demand (DYMO). A novel contribution of this work is enhancements in default
versions of selected routing protocols. Three performance parameters; PDR, E2ED
and NRO with varying scalabilities are measured to analyze the performance of
selected routing protocols with their original and enhanced versions. From
extensive simulations, it is observed that DSR outperforms among all three
protocols at the cost of delay. NS-2 simulator is used for simulation with
TwoRayGround propagation model to evaluate analytical results
Modeling Enhancements in DSR, FSR, OLSR under Mobility and Scalability Constraints in VANETs
Frequent topological changes due to high mobility is one of the main issues
in Vehicular Ad-hoc NETworks (VANETs). In this paper, we model transmission
probabilities of 802.11p for VANETs and effect of these probabilities on
average transmission time. To evaluate the effect of these probabilities of
VANETs in routing protocols, we select Dynamic Source Routing (DSR), Fish-eye
State Routing (FSR) and Optimized Link State Routing (OLSR). Framework of these
protocols with respect to their packet cost is also presented in this work. A
novel contribution of this work is enhancement of chosen protocols to obtain
efficient behavior. Extensive simulation work is done to prove and compare the
efficiency in terms of high throughput of enhanced versions with default
versions of protocols in NS-2. For this comparison, we choose three performance
metrics; throughput, End-to-End Delay (E2ED) and Normalized Routing Load (NRL)
in different mobilities and scalabilities. Finally, we deduce that enhanced DSR
(DSR-mod) outperforms other protocols by achieving 16% more packet delivery for
all scalabilities and 28% more throughput in selected mobilities than original
version of DSR (DSR-orig)
Equation-Method for correcting clipping errors in OFDM signals
Orthogonal frequency division multiplexing (OFDM) is the digital modulation technique used by 4G and many other wireless communication systems. OFDM signals have significant amplitude fluctuations resulting in high peak to average power ratios which can make an OFDM transmitter susceptible to non-linear distortion produced by its high power amplifiers (HPA). A simple and popular solution to this problem is to clip the peaks before an OFDM signal is applied to the HPA but this causes in-band distortion and introduces bit-errors at the receiver. In this paper we discuss a novel technique, which we call the Equation-Method, for correcting these errors. The Equation-Method uses the Fast Fourier Transform to create a set of simultaneous equations which, when solved, return the amplitudes of the peaks before they were clipped. We show analytically and through simulations that this method can, correct all clipping errors over a wide range of clipping thresholds. We show that numerical instability can be avoided and new techniques are needed to enable the receiver to differentiate between correctly and incorrectly received frequency-domain constellation symbols
Penggunaan Garam Beriodium Tingkat Rumah Tangga di Kecamatan Sibolga Utara, Kota Sibolga
The use of iodized salt in the household is highly recommended because of the iodine function that is essensial for the human body. This survey aims to test the iodine content qualitatively and study the use of iodized salt at the household level in North Sibolga sub-district, Sibolga city.The analytical survey with cross sectional design was conducted in 19 integrated service posts (POSYANDU) located in the working area of Pintu Angin Public Health Centre (PUSKESMAS Pintu Angin) in November 2016. The respondents in this survey were representatives of household member who came to POSYANDU and brought the salt commonly consumed by family. A total of 237 respondents were interviewed. Respondents were interviewed using structured questionnaire. Rapid test of iodine content in salt using reagent kit (PT Kimia Farma) was done to test he iodine qualitatively. Survey results show that all of households of respondents use salt in packs that have labeled “iodized salt” or similar statements. However, from iodine rapid test results found 2.5% of households whose iodine content in ithe salt has been lost. The quality of iodine content in salt at the household is significantly influenced only by salt storage (open or closed)
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