1. A Study of the Bandwidth Management Architecture over IEEE 802
A Study of the Bandwidth Management Architecture over IEEE WiMAX
Student : Sih-Han Chen ( 陳思翰 )
Advisor : Ho-Ting Wu ( 吳和庭 )
Date :

2. Outline Background and Motivation Proposed QoS System Architecture
Call Admission Control (CAC)
Pairing CAC
Bandwidth Borrowing on CAC level
Two Stage Bandwidth Allocation
Performance Evaluation
Conclusion and Future Work
2008/07/25

3. Background
Fixed WiMAX (Worldwide Interoperability for Microwave Access)
Specified by IEEE d
Wireless MAN Network
High transmission rate and coverage (75Mbps ,50km)
Support QoS
Cost saving and easy to deploy
Replace last mile (like ADSL)
2008/07/25

4. MAC Common Part Sublayer
Defines multiple-access mechanism
Functions ：
Connection establishment
Connection maintenance
Call admission control
Bandwidth request
Bandwidth allocation
Packet scheduling
MAC Common Part Sublayer
(MAC CPS)
2008/07/25

5. IEEE 802.16 TDD Frame Structure
2008/07/25

6. Service Classes Feature Application UGS Real Time Constant Bit Rate
(Unsolicited Grant Service)
Real Time
Constant Bit Rate
T1/E1
VoIP
rtPS
(Real-Time Polling Service)
Variable Bite Rate
MPEG video
nrtPS
(Non-Real-Time Polling Service)
Non-Real Time
FTP BE
(Best Effort)
No QoS guarantee
HTTP
2008/07/25

7. Dynamic Service Establishment
2008/07/25

8. Motivation
IEEE only defined the basic QoS signaling architecture.
The detail internal algorithm was left as the responsibility of implementers.
Call admission control
Bandwidth allocation
Packet scheduling
Pairing connection property
Uplink and downlink connections must coexist for many network application. (e.g. VoIP, FTP, P2P…)
Undefined!!!
2008/07/25

9. Outline Background and Motivation Proposed QoS System Architecture
Call Admission Control (CAC)
Pairing CAC
Bandwidth Borrowing on CAC level
Two Stage Bandwidth Allocation
Performance Evaluation
Conclusion and Future Work
2008/07/25

10. Proposed QoS ArchitectureBS SS
Connection Request
Pair Call Admission Control
Bandwidth
Borrowing
Agent
Applications
Core Network
Connection Response
Uplink
Data Traffic
Downlink
Data Traffic
UGS
rtPS
nrtPS BE
UGS
rtPS
nrtPS BE
Two Stage
Bandwidth Allocation
Two Stage
Bandwidth Allocation
Up Stream
(Bandwidth Request)
Downlink Packet Scheduler
Uplink Packet Scheduler
Down Stream
(DL/UL MAP)
2008/07/25

11. Pairing Call Admission Control
Symbol
Definition
Remaining Available System Bandwidth Resource
Reserved Bw for Connection, ( X = DL or UL )
Peak Traffic Rate of Connection Request, ( X = DL or UL)
Average Traffic Rate of Connection Request, ( X = DL or UL)
Min Traffic Rate of Connection Request, ( X = DL or UL)
2008/07/25

12. Pairing Call Admission Control
Each Pair
Connection
Request
Bavailable >= Y
Is UGS? Y N
Accept
Pair Call Y
Is rtPS? N N
Enable
Bandwidth
Borrowing ? Y Y
Is nrtPS? Go
Bandwidth Borrowing
Agent N N Y
Is BE?
Reject Call
2008/07/25

13. Range of Bandwidth Reservation
Service Type
Upper Bound of
Reserved Bandwidth
Low Bound of
UGS
rtPS
nrtPS BE
2008/07/25

14. Bandwidth Borrowing on CAC Level
Symbol
Definition
The current reserved bandwidth for connection i
The low bound of reserved bandwidth for connection i.
Amount of bandwidth are needed to be borrowed from system.
In system, How many bandwidth can be borrowed from rtPS, nrtPS and BE individually.
(X = rtPS , nrtPS or BE )
2008/07/25

15. Operation of Bandwidth Borrowing
Calculate the bandwidth that are needed to be borrowed from system
In system, the bandwidth can be borrowed from rtPS, nrtPS and BE individually
2008/07/25

16. Bandwidth Borrowing Flow Chart
Accept
Pair Connection Request from CAC Module
Reject
Success
Success
Success
Borrow
from existing
BE Cons
Borrow
from existing
nrtPS Cons
Borrow
from existing
rtPS Cons
Failure
Failure Y
Is UGS?
Failure
Accept N
Success
Reject
Success
Success
Borrow
from existing
BE Cons
Borrow
from existing
nrtPS Cons
Borrow
from existing
rtPS Cons Y
Failure
Failure
Is rtPS?
Failure
Is nrtPS? Y N
Reject Y
Is BE?
2008/07/25

17. Example of Bandwidth Borrowing (BB)
Existing Connections in System
CID
Type
Reserved BW
Low Bound of
Reserved Bw
Credit 1 BE
100 Kbps
Kbps
50 Kbps 2
nrtPS
150 Kbps 3
rtPS
300 Kbps 4
200 Kbps BS SS
Pairing UGS DSA
Total require 160Kbps(80x2)
Now System available Bw= 0
Start to BB operations at BS.
After Bandwidth Borrowing Operation
2008/07/25

18. Example of Bandwidth Borrowing (BB)
Existing Connections in System
CID
Type
Reserved BW
Low Bound of
Reserved Bw
Credit 1 BE
100 Kbps
Kbps
50 Kbps 2
nrtPS
150 Kbps 3
rtPS
300 Kbps 4
200 Kbps BS SS
Pairing UGS DSA
Total require 160Kbps(80x2)
Now System available Bw= 0
Start to BB operations at BS.
Borrow from exiting BE connections.
160 – 50 = 110 Kbps
After Bandwidth Borrowing Operation
Existing Connections in System
CID
Type
Reserved BW
Low Bound of
Reserved Bw
Credit 1 BE
50 Kbps
Kbps
0 Kbps
2008/07/25

19. Example of Bandwidth Borrowing (BB)
Existing Connections in System
CID
Type
Reserved BW
Low Bound of
Reserved Bw
Credit 1 BE
100 Kbps
Kbps
50 Kbps 2
nrtPS
150 Kbps 3
rtPS
300 Kbps 4
200 Kbps BS SS
Pairing UGS DSA
Total require 160Kbps(80x2)
Now System available Bw= 0
Start to BB operations at BS.
Borrow from exiting BE connections.
160 – 50 = 110 Kbps
After Bandwidth Borrowing Operation
Existing Connections in System
CID
Type
Reserved BW
Low Bound of
Reserved Bw
Credit 1 BE
50 Kbps
Kbps
0 Kbps
(2) Borrow from exiting nrtPS connections.
110 – 50 = 60 Kbps 2
nrtPS
100 Kbps
0 Kbps
2008/07/25

20. Example of Bandwidth Borrowing (BB)
Existing Connections in System
CID
Type
Reserved BW
Low Bound of
Reserved Bw
Credit 1 BE
100 Kbps
Kbps
50 Kbps 2
nrtPS
150 Kbps 3
rtPS
300 Kbps 4
200 Kbps BS SS
Pairing UGS DSA
Total require 160Kbps(80x2)
Now System available Bw= 0
Start to BB operations at BS.
Borrow from exiting BE connections.
160 – 50 = 110 Kbps
After Bandwidth Borrowing Operation
Existing Connections in System
CID
Type
Reserved BW
Low Bound of
Reserved Bw
Credit 1 BE
50 Kbps
Kbps
0 Kbps
(2) Borrow from exiting nrtPS connections.
110 – 50 = 60 Kbps
(3) Borrow 45Kbps from CID3
Borrow 15Kbps from CID4
60 * 150/(150+50) = 45
60 * 50/(150+50) = 15 2
nrtPS
100 Kbps
0 Kbps 3
rtPS
255 Kbps
150 Kbps
105 Kbps 4
185 Kbps
35 Kbps
2008/07/25

21. Example of Bandwidth Borrowing (BB)
Existing Connections in System
CID
Type
Reserved BW
Low Bound of
Reserved Bw
Credit 1 BE
100 Kbps
Kbps
50 Kbps 2
nrtPS
150 Kbps 3
rtPS
300 Kbps 4
200 Kbps BS SS
Pairing UGS DSA
Total require 160Kbps(80x2)
Now System available Bw= 0
Start to BB operations at BS.
Borrow from exiting BE connections.
160 – 50 = 110 Kbps
After Bandwidth Borrowing Operation
Existing Connections in System
CID
Type
Reserved BW
Low Bound of
Reserved Bw
Credit 1 BE
50 Kbps
Kbps
0 Kbps
(2) Borrow from exiting nrtPS connections.
110 – 50 = 60 Kbps
(3) Borrow 45Kbps from CID3
Borrow 15Kbps from CID4
60 * 150/(150+50) = 45
60 * 50/(150+50) = 15 2
nrtPS
100 Kbps
0 Kbps 3
rtPS
255 Kbps
150 Kbps
105 Kbps 4
185 Kbps
35 Kbps
BB Success !!! 5
UGS
80 Kbps
0 Kbps 6
Accept the Pairing UGS Call
2008/07/25

22. Two Stage Bandwidth Allocation
Stage One：
Allocate the guaranteed reserved bandwidth for each existing connection at most.
Stage Two: Allocate the remaining bandwidth
First, satisfy all rtPS connections that require more BW.
Final, allocate the remaining BW to nrtPS and BE evenly.
2008/07/25

23. Two Stage Bandwidth Allocation
2008/07/25

24. Outline Background and Motivation Proposed QoS System Architecture
Call Admission Control (CAC)
Pairing CAC
Bandwidth Borrowing on CAC level
Two Stage Bandwidth Allocation
Performance Evaluation
Conclusion and Future Work
2008/07/25

25. Simulation Environment
Values
Number of BS 1
Number of SS
5 - 50
Traffic types generated by each SS
UGS, rtPS, nrtPS, BE
Total Bandwidth
64 Mbps
Total Simulation Time
1000 Seconds
Frame Duration
10 ms
2008/07/25

26. Traffic Generation and Simulation Environment
UGS
rtPS
nrtPS BE
Application
VoIP
Video Stream
FTP
Average Data Rate
64 Kbps
DL：387Kbps
UL：38.7Kbps
DL：320Kbps
UL：32Kbps
192 Kbps
Maximum Sustained Traffic Rate
DL：464.4Kbps
UL：46.44Kbps
DL：384Kbps
UL：38.4Kbps
230.4Kbps
Minimum Reserved Traffic Rate
DL：309.6Kbps
UL：30.96Kbps
DL：256Kbps
UL：25.6Kbps
153.6Kbps
Low Bound of Reserved BW
Max Rate
Avg Rate
Min Rate
Call Inter Arrival Time
15 Seconds
Exponential
37.5 Seconds
30 Seconds
10 Seconds
Call Duration
120 seconds
240 seconds
60 seconds
20 seconds
Maximum Latency
20 ms
50 ms
100 ms
400 ms
Packet Size
160 Bytes
Fixed-Size
Bytes
Uniform
Packet Inter Arrival Time
Fixed Period
DL : ms
UL : 163.5ms
DL：20 ms
UL：200ms
33ms
2008/07/25

27. Simulation Experiment 1
Pairing vs NonPairing
Call Admission Control
2008/07/25

28. Definition of NonPairing CAC Reject Call
2008/07/25

29. Call Blocking Probability Pairing vs NonPairing
I + II
I + II
UGS
rtPS
Pair II II I
Pair I
2008/07/25

30. Call Blocking Probability Pairing vs NonPairing
I + II
I + II
nrtPS BE
I I
Pair
I I
Pair I I
2008/07/25

31. Summary of Experiment 1 Pairing CAC is better than NonPairing CAC
Pairing CAC really achieves higher performance than NonPairing CAC on call blocking probability.
What cause NonPairing CAC low performance?
The reply connection request is always rejected leading to high blocking probability of NonPairing Type II .
So the following next experiment will base on Pairing CAC scheme to study Bandwidth Borrowing scheme continually.
2008/07/25

32. Simulation Experiment 2
Based on Pairing Call Admission Control
Bandwidth Borrowing vs
Non Bandwidth Borrowing
2008/07/25

33. Call Blocking Probability Using Bandwidth Borrowing (BB)
Pairing CAC without BB
Pairing CAC with BB
rtPS
rtPS
2008/07/25

34. Packet Drop Rate ─ Non BB vs BB
rtPS
nrtPS BE
2008/07/25

35. Conclusion Proposed a novel QoS architecture over WiMAX, including :
Pairing Call Admission Control (CAC)
Bandwidth Borrowing scheme on CAC level
Two Stage Bandwidth Allocation
Dynamic Downlink and Uplink bandwidth allocation.
2008/07/25

36. Future work Different traffic pattern (self-similar traffic)
Extent to IEEE e mobility issue (handover call, signal strength)
End to End QoS guarantee (ASN, CSN)
Heterogeneous Network (integrated with WiFi, 3G system, or EPON)
2008/07/25

37. Q & A
Thanks for Your Attention

38. Worldwide Interoperability for Microwave Access ( WiMAX )
Bandwidth
IEEE IEEE IEEE GPP
1 Gbps
High Speed
Wireless
PAN
Wi-Fi
802.11n
100 Mbps
WiMAX
802.16 (
& e)
Wi-Fi
802.11a/b/g
10 Mbps 4G 3G
2.5G
1 Mbps
Bluetooth
<1m m m Up to 50Km Up to 80Km
PAN
LAN
MAN
WAN
PAN: Personal area networks MAN: Metropolitan area networks
LAN: Local area networks Wide area networks
2008/07/25

39. IEEE Operation Mode
2008/07/25

40. IEEE 802.16 d Specify area Topology of Operation Mode Multiplex
MAC layer
PHY layer
Topology of Operation Mode
PMP (Point to Multiple Point)
Mesh
Multiplex
TDD
FDD
2008/07/25

41. Bandwidth Request SSs may request bandwidth in 3 ways:
Contention-based bandwidth requests (Broadcast Polling or Multicast Group Pollng)
Contention-free bandwidth requests (Unicast Polling)
Piggyback a BW request message on a data packet
2008/07/25

42. Bandwidth Allocation BS grants/allocates bandwidth in one of two modes
Grant Per Subscriber Station (GPSS)
Grant Per Connection (GPC)
How much bandwidth to be granted based on -
Requested BW
QoS parameters
Available resources
Grants are realized through the UL-MAP
2008/07/25

43. Service Flow The central concept of the MAC protocol
A service flow is a unidirectional flow of packets that is provided a particular QoS.
SS and BS provide this QoS according to the QoS parameter set.
Existing in both uplink and downlink and may exist without being activated.
Must have a 32bit SFID, besides admitted and active status also have a 16-bit CID
2008/07/25

44. Definition of Pairing and Non Pairing CAC
2008/07/25

45. Definition of NonPairing CAC Accept Call
Round Trip Time:
The duration time between admitting Uplink Connection Reqest and BS send out the Downlink Connection Request.
2008/07/25

46. Operation of Bandwidth Borrowing (2)If
the bandwidth borrowed from every exiting BE connection i is：
Else, try to borrow bandwidth from nrtPS
after borrowing all bandwidth of
2008/07/25

47. Operation of Bandwidth Borrowing (3)If
the bandwidth borrowed from every exiting nrtPS connection i is：
Else, try to borrow bandwidth from rtPS
after borrowing all bandwidth of
2008/07/25

48. Operation of Bandwidth Borrowing (4)If
the bandwidth borrowed from every exiting rtPS connection i is：
Else, Bandwidth Borrowing Fail !
Reject the connection request.
2008/07/25

49. Mandatory Packet Scheduling Algorithm
Scheduling Service
Mandatory Algorithm
UGS
First In First Out (FIFO)
rtPS
Earliest Deadline First (EDF)
nrtPS
Weighted Fair Queue (WFQ) BE
Round Robin (RR)
2008/07/25

50. System Model of Simulation Experiment
Note : We assume that only SS can send the connection request to BS actively
2008/07/25

51. Traffic Generation and Simulation Environment
UGS
rtPS
nrtPS BE
Application
VoIP
Video Stream
FTP
Average Data Rate
64 Kbps
DL：387Kbps
UL：38.7Kbps
DL：320Kbps
UL：32Kbps
192 Kbps
Maximum Sustained Traffic Rate
DL：464.4Kbps
UL：46.44Kbps
DL：384Kbps
UL：38.4Kbps
230.4Kbps
Minimum Reserve Traffic Rate
DL：309.6Kbps
UL：30.96Kbps
DL：256Kbps
UL：25.6Kbps
153.6Kbps
Accept Call Criteria
Max Rate
64Kbps
(Max+Avg)/2
DL：425.7Kbps
UL：42.57Kbps
(Avg+Min)/2
DL：288Kbps
UL：28.8Kbps
Min / 2
76.8Kbps
Low Bound of Guarantee Bw
Avg Rate
Min Rate
Call Inter Arrival Time
15 Seconds
Exponential
37.5 Seconds
30 Seconds
10 Seconds
Call Duration
120 seconds
240 seconds
60 seconds
20 seconds
2008/07/25

52. Traffic Generation and Simulation Environment
UGS
rtPS
nrtPS BE
Maximum Latency
20 ms
50 ms
100 ms
400 ms
Schedule Scheme
FIFO
EDF
WFQ RR
Packet Size
160 Bytes
Fixed-Size
Bytes
Uniform
Packet Fragment
80 Bytes
240 Bytes
120 Bytes
Packet Inter Arrival Time
Fixed Period
DL : ms
UL : 163.5ms
DL：20 ms
UL：200ms
33ms
Reserve Bw
Per frame
(Non Bandwidth Borrowing Mode)
DL： B
UL： B
DL：360 B
UL：36 B
96 Bytes
2008/07/25

53. Performance Metric Call Blocking Probability : Packet Drop Rate :
2008/07/25

54. Definition of Pairing CAC
Accepted :
Reject :
2008/07/25
Master's Defense

55. Definition of NonPairing CAC Reject Call
2008/07/25
Master's Defense

56. Definition of NonPairing CAC
Default RTT of DL connection request
： 0.5 seconds
Accepted :
First Type of Connection Fail :
Second Type of Connection Fail :
2008/07/25
Master's Defense

57. Where is the issue ? Call Blocking Probability - Pairing and NonPairing
Non Pairing CAC without BB
Pairing CAC without BB
2008/07/25

58. Call Blocking Probability Non BB vs BB
UGS
rtPS
2008/07/25

59. Call Blocking Probability Non BB vs BB
nrtPS BE
2008/07/25

60. Outline Introduction of IEEE802.16 and QoS
Proposed QoS System Architecture
Call Admission Control (CAC)
Pairing CAC
Bandwidth Borrowing on CAC level
Two Stage Bandwidth Allocation
Performance Evaluation
Conclusion and Future Work
2008/07/25

61. Example of Bandwidth Borrowing (BB)
System available Bw = 0
CID
Type
Reserved BW
Low Bound of
Reserved Bw
Credit 1 BE
100 Kbps
Kbps
50 Kbps 2
nrtPS
150 Kbps 3
rtPS
300 Kbps 4
200 Kbps BS SS
Pairing UGS DSA
Total require 160Kbps(80x2)
Now System avaible Bw= 0
Start to BB operations at BS.
Borrow from exiting BE connections.
160 – 50 = 110 Kbps
After Bandwidth Borrowing Operation
System available Bw = 0
CID
Type
Reserved BW
Low Bound of
Reserved Bw
Credit 1 BE
50 Kbps
Kbps
0 Kbps
(2) Borrow from exiting nrtPS connections.
110 – 50 = 60 Kbps
(3) Borrow 45Kbps from CID3
Borrow 15Kbps from CID4
60 * 150/(150+50) = 45
60 * 50/(150+50) = 15 2
nrtPS
100 Kbps
0 Kbps 3
rtPS
255 Kbps
150 Kbps
105 Kbps 4
185 Kbps
35 Kbps
BB Success !!! 5
UGS
80 Kbps
0 Kbps 6
Accept the Pairing UGS Call
2008/07/25

62. Range of Bandwidth Reservation
Rsv-UGS
Rsv-BE
Rsv-nrtPS
Rsv-rtPS
(Average+Min) /2
(Peak+Average) /2
Min/2
Min
Rate
Average
Rate
Peak
Rate
Rsv-nrtPS
Low Bound
Rsv-BE
Low Bound
Rsv-rtPS
Low Bound
2008/07/25

63. Call Blocking Probability Pairing CAC vs NonPairing
2008/07/25

64. NonPairing Call Blocking Probability (UGS) Type I vs Type II
2008/07/25

65. NonPairing Call Blocking Probability (rtPS) Type I vs Type II
2008/07/25

66. NonPairing Call Blocking Probability (nrtPS) Type I vs Type II
2008/07/25

67. NonPairing Call Blocking Probability (BE) Type I vs Type II
2008/07/25

68. Bandwidth Borrowing Schemes
Service Class of
Connection Request
Bandwidth Borrowing
from the exiting connections in system
Scheme_1
Scheme_2
Scheme_3
UGS
BE  nrtPS
BE  nrtPS  rtPS
rtPS
nrtPS
N/A BE
2008/07/25

69. Pairing Call Blocking Probability (UGS) BB vs NonBB
2008/07/25

70. Pairing Call Blocking Probability (rtPS) BB vs NonBB
2008/07/25

71. Pairing Call Blocking Probability (nrtPS) BB vs NonBB
2008/07/25

72. Pairing Call Blocking Probability (BE) BB vs NonBB
2008/07/25

73. Packet Drop Rate (rtPS) BB vs NonBB
2008/07/25

74. Packet Drop Rate (nrtPS) BB vs NonBB
2008/07/25

75. Packet Drop Rate (BE) BB vs NonBB
2008/07/25