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Outline. UTRAN Iub Dimensioning TaskUTRAN Dimensioning ProcedureM/G/1
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1. Dimensioning of UTRAN Iub Links for Elastic Internet Traffic - Based on a submission to ITC 19 Xi Li
University of Bremen
&
Richard Schelb
Siemens AG
E-Mail: xili@comnets.uni-bremen.de Use comnets slide formatUse comnets slide format
2. Outline UTRAN Iub Dimensioning Task
UTRAN Dimensioning Procedure
M/G/1 & M/G/R-PS model
Dimensioning Methods for Elastic Internet Traffic
M/G/R-PS for Application Performance
M/G/R/N-PS for Admission Control
Simulation Results
Conclusions
3. UTRAN Iub Dimensioning Task
4. UTRAN Dimensioning Task Call Admission Control
UTRAN Synchronization (3GPP TS 25.402)
Performed between RNC and Node B to guarantee a timely arrival of radio frames (i.e. FP PDUs) to be delivered on time to the air interface Is FP clear at this point, why discard FP PDUs?
3GPP Reference regarding TOAWS
the interaction of the radio link control layer (RLC) and the frame protocol layer as a transport resource needs a timely arrival of the radio frames (i.e. FP PDU), because radio frames arriving (downlink from RNC to NodeB) later than scheduled for the transmission on-air will be discarded resulting in a waste of Iub bandwidth (additional load due to re-transmission of discarded blocks, if RLC operates in acknowledged mode).
Is FP clear at this point, why discard FP PDUs?
3GPP Reference regarding TOAWS
the interaction of the radio link control layer (RLC) and the frame protocol layer as a transport resource needs a timely arrival of the radio frames (i.e. FP PDU), because radio frames arriving (downlink from RNC to NodeB) later than scheduled for the transmission on-air will be discarded resulting in a waste of Iub bandwidth (additional load due to re-transmission of discarded blocks, if RLC operates in acknowledged mode).
5. UTRAN Dimensioning Procedure The properly dimensioned Iub has to achieve two main targets:
Maximize the application performance (mainly average object transfer delay)
Minimize the percentage of radio frames or FP PDUs which are received after LTOA, referred to as “delayed FP PDU ratio” Concept of UTRAN dimensioning, use some charts.
the target is to determine either the acceptable load for a given Iub bandwidth/configuration or the necessary bandwidth/configuration for a specific traffic load. Due to the granularity of E1 it could also result in an interative approach (extend/decrease cell capacity of NodeB to allow good utilization of Iub line.
Firstly, the application performance (mainly response time for object transfers) has to fit to the requirements.
Secondly, the interaction of the radio link control layer (RLC) and the frame protocol layer as a transport resource needs a timely arrival of the radio frames (i.e. FP PDU), because radio frames arriving (downlink from RNC to NodeB) later than scheduled for the transmission on-air will be discarded resulting in a waste of Iub bandwidth (additional load due to re-transmission of discarded blocks, if RLC operates in acknowledged mode).
The percentage of FP PDUs exceeding the allowed time budget is referred to as “delayed FP PDUs” within this paper.
Concept of UTRAN dimensioning, use some charts.
the target is to determine either the acceptable load for a given Iub bandwidth/configuration or the necessary bandwidth/configuration for a specific traffic load. Due to the granularity of E1 it could also result in an interative approach (extend/decrease cell capacity of NodeB to allow good utilization of Iub line.
Firstly, the application performance (mainly response time for object transfers) has to fit to the requirements.
Secondly, the interaction of the radio link control layer (RLC) and the frame protocol layer as a transport resource needs a timely arrival of the radio frames (i.e. FP PDU), because radio frames arriving (downlink from RNC to NodeB) later than scheduled for the transmission on-air will be discarded resulting in a waste of Iub bandwidth (additional load due to re-transmission of discarded blocks, if RLC operates in acknowledged mode).
The percentage of FP PDUs exceeding the allowed time budget is referred to as “delayed FP PDUs” within this paper.
6. M/G/1 Model
7. M/G/R – PS Model
8. Elastic Internet Traffic Mostly Web traffic and File downloading
TCP/IP Protocol
Reliable delivery of data
TCP flow control – rate adaptation
Internet traffic is extremely varying presence of “burstiness”, self-similarity
– TCPs flow control deliver all objects within one page
– Pareto distributed page size Web model figureWeb model figure
9. Flow Level Model Serving time?
Serving time?
10. M/G/R-PS Model Give matlab figures about m/g/r ps modelGive matlab figures about m/g/r ps model
11. Extended M/G/R-PS Model M/G/R-PS model assumes ideal capacity sharing among active flows
TCP flow control – slow start and congestion avoidance
During the slow start phase, the available bandwidth assigned to a connection cannot be fully utilized
The slow start mechanism leads to the increase of the data transfer delay
12. Bandwidth Utilization Efficiency
13. Extended M/G/R-PS Model
14. TCP Procedure
15. Adjustment on the Extended M/G/R PS Model
16. Simulation Scenario
17. Simulation Setup Throughput
Transfer Delay per amount of data
Probability of blocked connections in the UTRAN
End-to-end FP PDU Delay
Delayed FP PDU Ratio Concept of UTRAN dimensioning, use some charts.
Concept of UTRAN dimensioning, use some charts.
18. Dimensioning for Elastic Traffic (without CAC)
19. Call Admission Control
20. M/G/R/N-PS Model
21. M/G/R/N-PS Model Probability of each state How implement the CAC??How implement the CAC??
22. M/G/R/N-PS vs. Simulation Results
23. Conclusions UTRAN Iub Dimensioning Task
Two key constraints (file transfer delay and FP PDU delay) for the dimensioning of the Iub interface
Discussion of analytical approaches for determining the application performance
CAC is used to protect against overload situations and guarantee the quality of service of each user, even for “best effort” class
M/G/R/N-PS model to determine the application performance of the system applying CAC
Need analytical approach to predict the FP performance
Further investigation on multiple RAB rates
Further investigation on the dimensioning approaches for mixing stream and elastic traffic giving higher priority for stream traffic