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Strategies for exploitation of the multiple timeslot flexibility in (E)GPRS
2002 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

One of the functions in GPRS/EGPRS (General Packet Radio Service/Enhanced GPRS) is the possibility for a user to increase the bandwidth by using more than one timeslot - multiple timeslots, or 'multislot'. Multislot capabilities are mainly introduced for increased user bit rate and better system capacity. However, this flexibility opens several new areas with possible improvements that need to be investigated. One example is load based channel coding. In most cases the limiting factor for higher bit rates is the number of timeslots, but that is not always the case. In systems with large bandwidth the limiting factor can instead be the round trip delays in the system, occurred by retransmissions. In a multislot case the bit rate is so high that the additional round trip time becomes a significant part of the total transmission time. In such scenarios, by choosing coding scheme based on current load, packet size and round trip time, it is shown that unused channels can be used for more robust channel coding. By doing so, some of the retransmissions can be avoided, with an increased bit rate as result. In this thesis, a channel coding more optimized for round trip time is shown to be a good way to increase both user bit rate and system capacity, by decreasing the delay. However, adding too much redundancy will decrease the bit rate: for example, it is shown that using MCS 6 instead of MCS 9 is never a good way to increase the bit rate, there are better ways to use the resources. The suggested algorithm gives higher bit rate and lower delay than ideal link adaption. Simulations indicate that a gain of up to 30% in bit rate and 50% in delay can be achieved.

Place, publisher, year, edition, pages
Keyword [en]
Technology, EGPRS, multislot, channel coding
Keyword [sv]
URN: urn:nbn:se:ltu:diva-45418ISRN: LTU-EX--02/365--SELocal ID: 31bc770f-8d95-426f-a243-462b1c5d9ecbOAI: diva2:1018708
Subject / course
Student thesis, at least 30 credits
Educational program
Engineering Physics, master's level
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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