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Outline Our Previous Work
Modeling UMTS Discontinuous Reception (DRX) Mechanism
A Novel Analytic Model for UMTS DRX with Bursty Packet Data Traffic
Analytic Model Numerical Results
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UMTS MS Receiver Activities
DRXcycle 1
DRXcycle 2
DRXcycle 3
inactivitytimer
expired
wakeup
wakeup
sleep period tS
time
power active mode power saving mode
wakeup
tD
tI
busyperiod
(a)
inactivitytimer
activated
packetarrival
(d)
packetarrival
(inactivitytimer stopped)
packetarrival
inactivityperiod
(b)inactivity
period
(c)
inactivitytimer
activated
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An M/G/1 Vacation Model (1)
Input parameters Poisson packet arrivals with rate λa
Packet service time tx with mean 1/λx and variance Vx
The inactivity timer threshold tI
The DRX cycle tD
The cost of wakeup ζ
MSATMWCDMA
Buffer
Node B
Processor
RNC
UMTSCore
Network
ExternalNetwork
UTRAN
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The UMTS DRX is modeled as a variant of the M/G/1 queue with multiple vacations.
Output measures Mean packet waiting time E[tw] Power saving factor Ps
An M/G/1 Vacation Model (2)
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Bursty Packet Data Traffic
First packet arrival to base station buffer
Last packet arrival to base station buffer
A packet service session
A packet call
The instances of packet arrivals to base station buffer
t
• Geometric number of packet calls in a session• Geometric number of packets in a packet call• Geometric (Exponential) reading time
• Geometric (Exponential) inter-packer arrival time
• Cut-off Pareto packet size
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An Embeded Markov Chain Model
t. . . . .State 1 State 1 State 2 State 4 State 1
Inactivity timer
expired
Inactivity timer
expired
State 3
(Sleep) (Sleep)
Session 1 Session 2
…
State 1 State 3
State 2 State 4
• State 1: Busy period + Inter-packet
call idle period• State 2: Busy period + Inter-session
idle period• State 3: Sleep period entered from State 1• State 4: Sleep period entered from State 2
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Analytic Model (1)
The derivation of power saving factor Ps
Total time
Sleep time
Ps = Sleep time / Total time
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Analytic Model (2)
The derivation of mean packet waiting time E[tw] Number of packets
Total waiting time
E[tw] = Total waiting time / Number of packets
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