Transcript Achieving the Quality of Service in IEEE 802.16

An Adaptive Deficit-based Scheduler
for IEEE 802.16e Networks
Nararat RUANGCHAIJATUPON
and
Yusheng JI
The Graduate University for Advanced Studies
National Institute of Informatics (NII), Japan
The 24th Asia-Pacific Advanced Network Meeting
August 27–31, 2007, Xi’an, P.R. China
IEEE 802.16e TDD mode
 Uplink and Downlink share the same
frequency but not in the same time
 Transmission units are in frames
 Downlink subframe & Uplink subframe
 Subframe is divided into minislots
 MAP message at the beginning of
each frame
 DL-MAP & UL-MAP
August 27-31, 2007
24th APAN Meeting
2
WiMAX TDD Frame Structure
August 27-31, 2007
24th APAN Meeting
3
Scheduling services in IEEE 802.16e
 Unsolicited Grant Service (UGS)
 Extended Real-Time Polling Service
(ertPS)
 Real-Time Polling Service (rtPS)
 Non Real-Time Polling Service (nrtPS)
 Best Effort Service (BE)
August 27-31, 2007
24th APAN Meeting
4
Scheduling services in IEEE 802.16e
(cont.)
 Unsolicited Grant Service (UGS)
 Real-time application with fixed data rate,
fixed size data packet
 Extended Real-Time Polling Service
(ertPS)
 Real-time application with fixed data
rate, variable size data packet
August 27-31, 2007
24th APAN Meeting
5
Scheduling services in IEEE 802.16e
(cont.)
 Real-Time Polling Service (rtPS)
 Real-time application with fixed data rate,
variable size data packet
 Non Real-Time Polling Service (nrtPS)
 Delay-tolerant application with variable
size data packets, which required
minimum data rate
 Best Effort Service (BE)
 Application with no minimum service
level
August 27-31, 2007
24th APAN Meeting
6
Request message(s)
 Dynamic Service Addition (DSA)
 Dynamic Service Change (DSC)
 Dynamic Service Delete (DSD)
August 27-31, 2007
24th APAN Meeting
7
QoS parameters
 Maximum Sustained Traffic Rate
(rmax)
 Minimum Reserved Traffic Rate (rmin)
 Maximum Latency (tlatency)
 Minimum Tolerable Traffic Rate (rtol)
with time base (ttol)
 The minimum amount of traffic served
(in bits) during an arbitrary time interval
should not be less than (rtol x ttol)
August 27-31, 2007
24th APAN Meeting
8
Admission control
 Total bandwidth (BWtotal)
 A new flow j is accepted if:
BWtotal   rmin (i)  rmin ( j )  0
iU
 BE flows are always accepted as its rmin
always equals to zero
August 27-31, 2007
24th APAN Meeting
9
Parameters and states
 Connection’s limited queue size
qlimit (i)  rmin (i)  t frame
 Burst state
 Connection queue size is more than its
limited queue size
 Non-burst state
 Connection queue size is equal or less
than its limited queue size
August 27-31, 2007
24th APAN Meeting
10
Proposed scheduling scheme
 All flows are in
non-burst state
q(i )
 Cavailable
 q(i)
Queue size limit
Flow 1
DL ertPS,
rtPS, nrtPS
…
Flow 1
UL ertPS,
rtPS, nrtPS
 A flow is in burst
state
Adaptive DRR
Flow n
iA
Adaptive DRR
Scheduler
with EDF
Flow n
DL BE
…
RR
UL BE
…
 Tolerable group
 Guaranteed group
 Burst group
August 27-31, 2007
FIFO
UL UGS
…
quantum(i ) 
FIFO
DL UGS
RR
24th APAN Meeting
11
Adaptive quantum
 Tolerable category
quantumtol (i)  min[q(i), rtol (i)  t frame ]
 Guaranteed category
quantumguarantee (i)  min[q(i), qlimit (i)]
August 27-31, 2007
24th APAN Meeting
12
Adaptive quantum
(cont.)
 Burst category
If
 q(i)  C
iZ
available
quantumburst (i)  q(i)
Else
Employ max-min allocation
Cavailable  Ctotal  CUGS   quantumguarantee (i)   quantumtol (i)
iX
August 27-31, 2007
24th APAN Meeting
iY
13
Simulation Setup




Single base station
Frame duration: 2.5 ms
Number of slots per frame: 175,000
Total bandwidth : 75 Mbps
 PHY/MAC control message takes 5 Mbps
 One minislot represents a single physical slot
(PS) with a baud rate of one
 Traffic utilization is 85.71 %
August 27-31, 2007
24th APAN Meeting
14
Traffic and request generators
August 27-31, 2007
24th APAN Meeting
15
Simulation results
Throughput of DL ertPS traffic
Throughput of UL ertPS traffic
350
350
DL ertPS src
DL ertPS allocated
330
320
UL ertPS request
UL ertPS allocated
340
Throughput (kbits)
Throughput (kbits)
340
310
300
290
280
270
260
330
320
310
300
290
280
270
260
250
250
0
1
2
3
4
5
0
1
2
Time (sec)
Throughput of DL rtPS traffic
4
5
Throughput of UL rtPS traffic
800
800
DL rtPS src
DL rtPS allocated
700
UL rtPS request
UL rtPS allocated
700
600
Throughput (kbits)
Throughput (kbits)
3
Time (sec)
500
400
300
200
100
600
500
400
300
200
100
0
0
0
1
2
3
4
5
Time (sec)
August 27-31, 2007
0
1
2
3
4
5
Time (sec)
24th APAN Meeting
16
Simulation results
(cont.)
Throughput of DL nrtPS traffic
Throughput of UL nrtPS traffic
800
800
DL nrtPS src
DL nrtPS allocated
UL nrtPS request
UL nrtPS allocated
700
600
Throughput (kbits)
Throughput (kbits)
700
500
400
300
200
100
600
500
400
300
200
100
0
0
0
1
2
3
4
5
0
1
2
Time (sec)
Throughput of DL BE traffic
4
5
Throughput of UL BE traffic
1000
1000
DL BE src
DL BE allocated
900
800
700
600
500
400
300
700
600
500
400
300
200
200
100
0
100
0
0
1
2
3
4
5
Time (sec)
August 27-31, 2007
UL BE request
UL BE allocated
900
Throughput (kbits)
800
Throughput (kbits)
3
Time (sec)
0
1
2
3
4
5
Time (sec)
24th APAN Meeting
17
Fairness
Fairness Comparison
1
0.9
DFPQ
0.8
Adaptive with MaxMin allocation
0.7
Fairness
“A scheduler is
considered to be fair if
the difference in
normalized service
received by different
flows is bounded.”
0.6
0.5
0.4
0.3
0.2
Thi Th j
Fairness 

ri
rj
August 27-31, 2007
0.1
0
100
102
104
106
108
110
112
114
Total traffic ( % of maximum kbits/frame)
24th APAN Meeting
18
Conclusion
 An adaptive deficit-based scheduler for
IEEE 802.16e adapts the allocation
appropriately to the input traffic and
uplink request
 The proposed scheme also shows better
performance in fairness
 Further work must be done on
unbalance traffic and cross-layer
scheduling
August 27-31, 2007
24th APAN Meeting
19
Thank you very much
 Questions and Answers