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bytes
bytes minutes Transfer time vs. Packet loss
minutes
loss
Transfer time vs. Packet
Transferred data vs. Packet loss
Transferred data vs. Packet loss
4,0
- ^~- »\
120000
120000
3,5
MCRS_VPN
FTP_VPN
FTP_VPN '* . FTP
FTP
100000
100000 3,0
80000 2,5
80000
\ ^1 ' 2,0 MCRS
IE
60000
60000 FTP FTP_VPN
IE_VPN
\ . IE_VPN \ ; 1,5
40000
40000 IE_VPN
MCRS VPNN 1,0
MCRS VP
IE
20000 0,5
20000
MCRS
MCRS
0 0 0,0
1 1 2 3 4 1 2 3 4
Figure 3: Transferred data and transfer times as a function of packet loss
CONCLUSIONS
Simulation shows how different applications operate in varying GPRS conditions. The QoS in GPRS is
difficult to apply in applications that would need a guaranteed level of link quality for their operation.
Therefore QoS was studied from the point of view of how these applications operate in variable GPRS
conditions. The research studied extreme limits for operation and it is natural that the usability of the
applications is very poor close to these limits.
MCRS tolerates delays and jitters very well whether VPN is used or not. The difference is that when
using VPN the amount of data transferred is considerably higher than without it. The same is valid in
situations where the amount of lost packets increases. As the GPRS link quality decreases drastically
the system operates in some fashion but usability is lost. The simulated access time from mobile to
MGS varies between 30 and 35 seconds depending on whether VPN tunnelling is used. The time is so
long because a large of amount of data (>20kB) is transferred during this process compared to the
actual page size (0,5kB). From earlier research it can be noted that without the certification phase the
access time to the MGS is less than 5 seconds in practice. Thus there is development work to do to
attain a highly secure and usable system.
In the future mobile UMTS networks will come in to evermore practical and wider use. The reference
[5] presents the evolved QoS properties of UMTS compared to GPRS. This together with enhanced
data transfer capacity should help to implement remote control applications even with modest real-time
requirements.
References
[1] Soini M., Eeva T., Sydanheimo L. and Kivikoski M. (2004). The Mobile Controlled RFID System.
th
11 IF AC Symposium on Information Control Problems in Manufacturing (1NCOM2004).
[2] Ruohonen T., Ukkonen L., Soini M., Sydanheimo L. and Kivikoski M. (2004). Quality and
reliability of GPRS connections. 2004 IEEE Consumer Communications and Networking Conference
(CCNC2004).
[3] Samjani A. (2002). General Packet Radio Service. IEEE potentials. 21:2, 12-15.
[4] ETSI EN 301 113 v6.3.1 (2000). Digital cellular telecommunications system (Phase 2+), General
Packet Radio Service (GPRS), Service description, Stage 1.
[5] Koodli R. and Puuskari M (2001). Supporting Packet-Data QoS in Next Generation Cellular
Networks. IEEE Communications Magazine. 39:2, 180-188.
[6] Bettstetter C, Vogel H. J. and Eberspacher J. (1999). GSM Phase 2+ General Packet Radio Service
GPRS Architecture, Protocols, and Air Interface. IEEE Communications Surveys, 2:3, 2-14.