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Traffic Descriptions For 802.11E Performance Simulation. Jin-Meng Ho Texas Instruments Incorporated 12500 TI Blvd. Dallas, Texas 75243 (214) 480-1994 jinmengho@ti.com. Objectives. Serves as a starting common simulation scenario for evaluation of 802.11e QoS MAC proposals.
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Traffic DescriptionsFor 802.11E Performance Simulation Jin-Meng Ho Texas Instruments Incorporated 12500 TI Blvd. Dallas, Texas 75243 (214) 480-1994 jinmengho@ti.com
Objectives • Serves as a starting common simulation scenario for evaluation of 802.11e QoS MAC proposals. • Provides more details of the simulation scenario outlined as Model 3 in doc 196r2 for 11 Mbps home environments. • Generates other simulation scenarios that are applicable to other PHY rates and operation environments.
Outline • Topology of traffic categories • Models of traffic sources • Voice • Video Conferencing • MPEG2 • Data • Web Requests, Web Objects • File Transfers, Image Transfers • Emails
Simulation Scenario for 802.11B (11 Mbps Home Environments) STA1 STA2 Voice • Priority levels: • BE = 0 • LP = 1 • MP = 2 • HP = 3 • MPEG2 = 4 • VC = 5 • Voice = 6 • R = 7 • E-DCF mappings: • BE = 0 • LP = 1 • MP = 1 • HP = 2 • MPEG2 = 2 • VC = 3 • Voice = 3 • R = 3 Web_Objects (LP) Web_Requests (LP) File Transfers (MP) Image Transfers (MP) Voice VC (Video Conferencing) AP/PC STA3 Outgoing Emails (BE) Incoming_Emails (BE) Web Objects (HP) Web Requests (HP) MPEG2 Voice Data (dotted) links may be idle most of the time. STA5 STA4
Total Traffic Source Rates • Total Traffic - Average aggregate rate: • Data Traffic (Webs + Emails + File/Image Transfers) - Average individual rates: --controls rate proportions among data links --controls aggregate data traffic rate - Average aggregate rate: Without MPEG2 loading With MPEG2 loading
Some Heavy-Tailed Distributions Lognormal ( ): Pareto ( ):
More Heavy-Tailed Distributions Weibull ( ): Gamma ( ):
Voice Traffic Models • Birectional • Source rate (in each direction) = 64 kb/s (CBR) • Inter-packet arrival time (to LLC) = 20 ms • Higher layer and WEP overhead (per MSDU) = 48 bytes • Net frame (MSDU) length = 208 bytes
Video Conferencing Traffic Models(From Doc 349) • Birectional • Source rate (in each direction) = 98.4 kb/s (CBR) • Packet arrival rate (to LLC) = 20 packets/s • Higher layer and WEP overhead (per MSDU) = 48 bytes • Net frame (MSDU) length = 663 bytes
MPEG2 Traffic Models(From Doc 349) • Unidirectional • Average source rate = 5.12 Mb/s (VBR) • Modeled by scenes, GOPs (group of pictures), and I/B/P frames • Higher layer overhead (per MSDU) = 40 bytes • Inter-frame arrival time (to LLC) = 33.33 ms • Frame length distributions (in bits): I B B P B B P B B P B B P B B I B B P B B P B B P B B P B B I GOP = 15 Frames = 0.5 secs GOP = 15 Frames = 0.5 secs
Data Traffic Models(Emails, Web Requests/Objects,File/Image Transfers) • Modeled by (hierarchical) renewal processes per-direction • Arrivals to LLC in bursts (which may be decomposed into frames) • Higher layer overhead included (absorbed) in models • Delay and jitter evaluated with respect to bursts, but not frames • λ (needed later) given on slide 5 under various channel loads
Email Traffic Models Outgoing Emails: Incoming Emails:
File/Image Traffic Models File Transfers: Image Transfers:
Web Traffic Models Web Requests (LP): Web Objects (LP):
Web Traffic Models (Cont) Web Requests (HP): Web Objects (HP):
Delay and Delay Variation Evaluation • Each burst of data arrivals (as illustrated by arrows and • characterized by RVs and in the previous slides) • represents a “message”, such as a user request, an web object, • and an embedded web reference. • A message is “meaningful” to the user only after the complete • burst of data arrivals has been received. • Delay and delay variation should be evaluated with respect to • messages, instead of “frames” into which messages may • decompose.