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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Analysis of a wireless cell with multiple service classes under an aggregate sharing scheme

Awan, Irfan U., Kouvatsos, Demetres D., Al-Begain, Khalid January 2002 (has links)
An analytic framework is devised for the performance modelling and evaluation of a wireless Global System for Mobile Telecommunication (GSM) cell with General Packet Radio Service (GPRS) supporting both multiple class voice and data services, respectively, under an aggregate sharing scheme (ASS). The investigation focuses on the study of a proposed GE/GE/c/N/PR/CBS queueing system with c (¿1) servers, finite capacity, N (¿c), generalised exponential (GE) GSM/GPRS interarrival and service times under pre-emptive resume (PR) priority rule and complete buffer sharing (CBS) scheme. The principle of maximum entropy (ME) is used t ocharacterise new closed form expressions for the state and blocking probabilities, subject to appropriate GE-type queueing theoretic constraints per class. Typical numerical examples are included to validate the ME solution against simulation at 95% confidence intervals and study the effect of external GMS/GPRS bursty traffic upon the performance of the cell.
2

Maintaining QoS through preferential treatment to UMTS services

Awan, Irfan U., Al-Begain, Khalid January 2003 (has links)
One of the main features of the third generation (3G) mobile networks is their capability to provide different classes of services; especially multimedia and real-time services in addition to the traditional telephony and data services. These new services, however, will require higher Quality of Service (QoS) constraints on the network mainly regarding delay, delay variation and packet loss. Additionally, the overall traffic profile in both the air interface and inside the network will be rather different than used to be in today's mobile networks. Therefore, providing QoS for the new services will require more than what a call admission control algorithm can achieve at the border of the network, but also continuous buffer control in both the wireless and the fixed part of the network to ensure that higher priority traffic is treated in the proper way. This paper proposes and analytically evaluates a buffer management scheme that is based on multi-level priority and Complete Buffer Sharing (CBS) policy for all buffers at the border and inside the wireless network. The analytical model is based on the G/G/1/N censored queue with single server and R (R¿2) priority classes under the Head of Line (HoL) service rule for the CBS scheme. The traffic is modelled using the Generalised Exponential distribution. The paper presents an analytical solution based on the approximation using the Maximum Entropy (ME) principle. The numerical results show the capability of the buffer management scheme to provide higher QoS for the higher priority service classes.

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