scholarly journals Traffic capacity improvement factor when VAMOS technique is applied

Tehnika ◽  
2021 ◽  
Vol 76 (2) ◽  
pp. 187-193
Author(s):  
Vladimir Matić ◽  
Dragan Mitić ◽  
Žarko Markov ◽  
Aleksandar Lebl ◽  
Verica Marinković-Nedelicki
Keyword(s):  
Total Loss ◽  
Simulation Program ◽  
Mobile Telephony ◽  
Emission Power ◽  
Improvement Factor ◽  
Traffic Capacity ◽  
Power Difference ◽  
Full Rate ◽  
Capacity Improvement ◽  
Modern Technologies

New modern technologies in mobile telephony overcome the possibilities of GSM systems. VAMOS technique is one way to improve traffic properties of traditional GSM systems. Our aim is to analyze the level of this improvement achieved by VAMOS implementation. The number of traffic resources is doubled, but it is proved that traffic capacity is more than doubled for full rate connections implementation and more than quadrupled for half rate connections regardless of offered traffic for all values of emission power difference between 4dB and 10dB when considering two paired subchannels. There are two loss types in VAMOS systems: unpairing loss and traffic loss when all subchannels are busy. The values of these two loss types whose sum presents the total loss in VAMOS systems are determined by originally developed simulation program. The achievable total loss may be decreased for 45% or even more when allowable power difference between paired channels is increased from 4dB to 10dB.

scholarly journals A novel method for the codecs’ performance analysis in mobile telephony systems

2020 ◽  
Vol 33 (2) ◽  
pp. 243-259
Author(s):  
Aleksandar Lebl ◽  
Dragan Mitic ◽  
Vladimir Matic ◽  
Mladen Mileusnic ◽  
Zarko Markov
Keyword(s):  
Quality Of Service ◽  
Flow Rate ◽  
Mobile Communications ◽  
Voice Quality ◽  
Mobile Telephony ◽  
Mobile Telecommunication ◽  
Telecommunication System ◽  
Full Rate ◽  
Novel Method

This paper presents a novel method of expressing the quality of service in a mobile telecommunication system when its performance depends on several factors including applied codecs? characteristics (voice quality and data flow rate) and telecommunications traffic service possibilities. The influence of these factors is unified in one variable - quality of service measure. The proposed method is especially applicable in the cases when two-dimensional systems are analyzed - for example when two codecs with different flow rate and different achievable connection quality are used in a system. As an example, we also studied system with full-rate or mixed full-rate and half-rate codec implementation depending on the offered traffic. The system performances - mean dataflow and mean connection quality as a function of offered traffic are presented graphically and also expressed quantitatively by the novel quality of service measure. The systems with different number of available traffic channels may be compared on the base of this novel evaluation value such that the system with the highest value is the most suitable one for the concrete situation. In this way mobile system design is simplified to the great extent. The developed model is applicable generally for mobile telephony systems defining, but in this paper we studied its implementation for Global System for Mobile communications.

Mobile phones in Africa: The politics of cultural and material integration into local economies

2020 ◽  
Vol 23 (4) ◽  
pp. 531-546
Author(s):  
James Odhiambo Ogone
Keyword(s):  
Mobile Phone ◽  
Mobile Phones ◽  
Informal Economy ◽  
Rapid Expansion ◽  
Mobile Telephony ◽  
African Continent ◽  
Local Economies ◽  
Political Role ◽  
The Subject ◽  
Modern Technologies

The rapid expansion of mobile telephony in Africa has been the subject of many debates both in the academia and industry. However, such discourse has tended to focus more on the technology itself rather than its users. This article seeks to frame mobile phones as modern technologies whose contextual uses are heavily entangled in the unique socio-economic dynamics of the African continent. Here the focus is on the African informal economy and the culture it enables, the fractious nature of infrastructure and practices of repair, African notions of conviviality and their political role, and African traditions in the context of globalization. Through these various lenses the study considers the different ways in which the mobile phone becomes Africanized.

scholarly journals Traffic Management Facilities Used at Intersection of Ukmergės and Geležinio Vilko Streets in Vilnius

2013 ◽  
Vol 14 (3) ◽  
pp. 187-195
Author(s):  
Vidmantas Pumputis ◽  
Giedrius Garbinčius ◽  
Valentin Mironov
Keyword(s):  
Experimental Investigation ◽  
Traffic Management ◽  
Traffic Simulation ◽  
Simulation Program ◽  
Traffic Intensity ◽  
Traffic Flows ◽  
Traffic Capacity ◽  
The City ◽  
Main Streets

Vilnius, the capital and the largest city of Lithuania, is faced with serious traffic problems. The main streets of the city are overcrowded with traffic. Therefore, the effective ways to ease the congestion should be sought. The paper considers the problem of high traffic intensity and congestion at the intersection of two busy Vilnius streets. Research is based on the analysis of the data stored at the Vilnius Traffic Management Centre and the information obtained in the experimental investigation of traffic flows. All the collected data have been used in the traffic simulation program, to make some effective measures helping to increase traffic capacity of the considered intersection.

scholarly journals Power saving technique based on traffic channels reallocation in GSM mobile network

2020 ◽  
Vol 71 (2) ◽  
pp. 103-109
Author(s):  
Vladimir Kosjer ◽  
Dragan Mitić ◽  
Aleksandar Lebl ◽  
Vladimir Matić ◽  
Žarko Markov
Keyword(s):  
Power Control ◽  
Density Distribution ◽  
Power Saving ◽  
Mobile Network ◽  
Simulation Program ◽  
Mobile Users ◽  
Main Principle ◽  
Emission Power

AbstractA mobile users’ network with power control on traffic channels, as it is GSM, is considered in this paper. It is analyzed the influence of busy channels reallocation on the necessary emission power. The main principle in reallocation is that users who need greatest power for their connections take traffic channels of the first carrier where power is always maximum. It is assessed that reallocation process is not more complicate than the simplest handover processes. It is proved that this method may be used to decrease emission power of carriers after the second one. Power saving depends on number of carriers, environmental propagation coefficient and users’ density distribution in the cell. The results are verified by originally developed simulation program.

Capacity Improvement Factor of HF Multi-Mode Skywave MIMO Channels

2019 ◽  
Author(s):  
T. I. Suharto ◽  
G. Hendrantoro ◽  
A. Mauludiyanto ◽  
U. Umaisaroh ◽  
R. Corputty ◽  
...  
Keyword(s):  
Mimo Channels ◽  
Improvement Factor ◽  
Capacity Improvement ◽  
Multi Mode

Microspectroscopy Using a Solid Immersion Lens

2001 ◽  
Vol 7 (S2) ◽  
pp. 148-149
Author(s):  
C.D. Poweleit ◽  
J Menéndez
Keyword(s):  
Spatial Resolution ◽  
Focal Plane ◽  
Numerical Aperture ◽  
Normal Incidence ◽  
Spot Size ◽  
Index Of Refraction ◽  
Objective Lens ◽  
Improvement Factor ◽  
Oil Immersion ◽  
Long Time

Oil immersion lenses have been used in optical microscopy for a long time. The light’s wavelength is decreased by the oil’s index of refraction n and this reduces the minimum spot size. Additionally, the oil medium allows a larger collection angle, thereby increasing the numerical aperture. The SIL is based on the same principle, but offers more flexibility because the higher index material is solid. in particular, SILs can be deployed in cryogenic environments. Using a hemispherical glass the spatial resolution is improved by a factor n with respect to the resolution obtained with the microscope’s objective lens alone. The improvement factor is equal to n2 for truncated spheres.As shown in Fig. 1, the hemisphere SIL is in contact with the sample and does not affect the position of the focal plane. The focused rays from the objective strike the lens at normal incidence, so that no refraction takes place.

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