Slide 1

LOG O IEEE 802.16 QoS Architecture 2010/03/31 1

Slide 2

Outline 1. Introduction 1. Introduction 2. IEEE 802.16 QoS Architecture 2. IEEE 802.16 QoS Architecture 5. Conclusion 5. Conclusion 3. Bandwidth Request 3. Bandwidth Request 4. Transmission Scheduling 4. Transmission Scheduling 2

Slide 3

Introduction 802.16 Deployment 3

Slide 4

Introduction 4

Slide 5

Service-Specific Convergence Sublayer(CS) : CS CID MAC CPS MAC Common Part Sublayer(MAC CPS) : 802.16 MAC BS SS management QoS ARQ(Automatic Repeat Request) Security Sublayer : BS SS Physical Layer : OFDM FFT 5

Slide 6

Introduction 6

Slide 7

7

Slide 8

Outline 1. Introduction 1. Introduction 2. IEEE 802.16 QoS Architecture 2. IEEE 802.16 QoS Architecture 5. Conclusion 5. Conclusion 3. Bandwidth Request 3. Bandwidth Request 4. Transmission Scheduling 4. Transmission Scheduling 8

Slide 9

QoS mechanisms Classification Mapping from MAC SDU fields (e.g destination IP address) to CID and SFID Scheduling Downlink scheduling module Simple, all queues in BS Uplink scheduling module Queues are distributed among SSs. Queue states and QoS requirements are obtained through BW requests. Algorithms not defined in standard 9

Slide 10

IEEE 802.16 QoS Architecture 10

Slide 11

Service Types 11

Slide 12

Service Types (cont.) 12

Slide 13

Service Types (cont.) Extended rtPS (ErtPS) UGS rtPS Ex: silence suppression VoIP BS UGS unicast grants SS ertPS BS QoS UGS BS SS BS SS bandwidth stealing piggyback 13

Slide 14

Service Types (cont.) 14

Slide 15

Service Types (cont.) 15

Slide 16

Comparison Table QoS CategoryApplicationQoS Specifications UGS Unsolicited Grant Service VoIP Maximum Sustained Rate Maximum Latency Jitter Tolerance rtPS Real-Time Polling Service Streaming Audio or Video Minimum Reserved Rate Maximum Sustained Rate Maximum Latency Tolerate Traffic Priority ErtPS Extended Real-Time Polling Service Voice with Activity Detection (VoIP) Minimum Reserved Rate Maximum Sustained Rate Maximum Latency Tolerate Jitter Tolerance Traffic Priority nrtPS Non-Real-Time Polling Service File Transfer Protocol (FTP) Minimum Reserved Rate Maximum Sustained Rate Traffic Priority BE Best-Effort Service Data Transfer, Web Browsing, etc. Maximum Sustained Rate Traffic Priority priority 16

Slide 17

Poll/Grant Options in Scheduling Services Scheduling Type Piggyback Request Bandwidth Stealing Polling UGSNot allowed PM bit is used to request a unicast poll for bandwidth needs of non-UGS connections. rtPSAllowed Scheduling only allows unicast polling. nrtPSAllowed Scheduling may restrict a service flow to unicast polling via the transmission/request policy; otherwise all forms of polling are allowed. BEAllowed All forms of polling allowed. ErtPSAllowed All forms of polling allowed 17

Slide 18

Outline 1. Introduction 1. Introduction 2. IEEE 802.16 QoS Architecture 2. IEEE 802.16 QoS Architecture 5. Conclusion 5. Conclusion 3. Bandwidth Request/Allocation 3. Bandwidth Request/Allocation 4. Transmission Scheduling 4. Transmission Scheduling 18

Slide 19

Bandwidth Management Bandwidth(BW) for a connection is allocated on a demand assignment basis. Unused bandwidth allocation will be withdrawn. Bandwidth is managed via Request/Grant Methods. UGS services arent necessary to be requested,since the resource needs are known in advance. Request can be used for all other services. Bandwidth cant taken from a UGS service (its guaranteed) while possible for other services. 19

Slide 20

Unicast polling Polled Request: polling sent from BS Unicast polling Sent on SSs basic CID Transmission opportunities in Request IE or Data Grant IE Data Grant IE can use a more efficient burst file Request IE can only use the Request IE burst file(UIUC=1) Unicast polling of an SS would normally be done by allocating a Data Grant IE directed at its Basic CID The transmission of BRs is contention-free 20

Slide 21

Unicast polling Unicast polling(cont.) 21

Slide 22

Multicast polling and broadcast polling Multicast polling and broadcast polling Sent on multicast CID or broadcast CID Only the members in the polled group will send BRs BRs are transmitted in a contention way and the contention resolution algorithm is applied BS shall individually poll the SSs periodically who dont have bandwidth allocated With only one active UGS connection(BW stealing and piggyback arent allowed), SS set PM bit asking BS to poll the SS In case no enough bandwidth available for individual polling, broadcast or multicast polling are used 22

Slide 23

Multicast polling and broadcast polling(cont.) Multicast and broadcast polling 23

Slide 24

Bandwidth Stealing Bandwidth Stealing SS uses a portion of allocated bandwidth for a connection for a connection to send another bandwidth requests rather than sending data Not allowed for UGS connection 24

Slide 25

Piggyback Request Piggyback Request The bandwidth request is piggybacked onto a MAC PDU on an existing connection with allocated bandwidth Not allowed for UGS connection The request is unsuccessful if no grant has been received in next few UL-MAP message 25

Slide 26

Bandwidth Allocation 802.16 MAC BS scheduler radio interface DL UL requested bandwidth, QoS parameters available resources Grant Per Subscriber Station (GPSS) BS SS Subscriber Station SS BS SS SS 26

Slide 27

Bandwidth Allocation (cont.) Downlink BS DL QoS BS scheduler SS downlink burst(s) burst profile Uplink SS BS SS UL QoS (UGS, rtPS, ertPS, nrtPS, and BE) BS UL unsolicited bandwidth grants piggyback bandwidth request unicast polling (polling) contention-based procedures (broadcast or multicast polling) 27

Slide 28

Outline 1. Introduction 1. Introduction 2. IEEE 802.16 QoS Architecture 2. IEEE 802.16 QoS Architecture 5. Conclusion 5. Conclusion 3. Bandwidth Request 3. Bandwidth Request 4. Transmission Scheduling 4. Transmission Scheduling 28

Slide 29

BS scheduler operation for UL 29

Slide 30

Transmission Scheduling Radio resources have to be scheduled according to the QoS (Quality of Service) parameters Uplink Scheduling the scheduling algorithms can be used : RR (Round Robin) WRR (Weighted Round Robin) WFQ (Weighted Fair Queuing) WFFQ (Worst-case Fair weighted Fair Queuing) VT (Virtual Time) DRR (Deficit Round Robin) DDRR (Distributed Deficit Round Robin) EDF (Earliest Deadline First) 30

Slide 31

WRR (Weighted Round Robin) The WRR algorithm is based on the Round Robin algorithm but it takes into account the processing capacity of each waiter. The administrators manually assign a coefficient of performance to each waiter. ( 1, 2 and 3 in the example). 31

Slide 32

WFQ (Weighted Fair Queuing) 32

Slide 33

EDF (Earliest Deadline First) A dynamic scheduling algorithm used in real-time operating systems. It places processes in a priority queue. Whenever a scheduling event occurs (task finishes, new task released, etc.) the queue will be searched for the process closest to its deadline. If there is a feasible schedule, then EDF produces a feasible schedule 33

Slide 34

Scheduling Example Packet scheduling for QoS support in IEEE 802.16 broadband wireless access systems QoS WiMAX This scheduling algorithm is proposed to assign: a fixed bandwidth for UGS, using Earliest Deadline First (EDF) technique for rtPS, Weighted Fair Queuing (WFQ) for nrtPS and equal distribution for BE. 34

Slide 35

BS scheduler operation for DL 35

Slide 36

Outline 1. Introduction 1. Introduction 2. IEEE 802.16 QoS Architecture 2. IEEE 802.16 QoS Architecture 5. Conclusion 5. Conclusion 3. Bandwidth Request 3. Bandwidth Request 4. Transmission Scheduling 4. Transmission Scheduling 36

Slide 37

Conclusion IEEE 802.16 MAC subchannel IEEE 802.16 QoS traffic real-time traffic latency jitter traffic QoS time slots QoS Wimax channel QoS channel packet scheduling 37

Slide 38

Future Work 3G/LTE, Wi-Fi QoS , 38

Slide 39

Reference [1] IEEE Std 802.16-2009 [2] A. Ganz, Z.Ganz and K.Wongthavarawat,Multimedia Wireless Networks: Technologies, Standards, and QoS, Prentice Hall PTR, 2003, ch.7 [3] L. Nuaymi, WiMAX: Technology for Broadband Wireless Access, Wiley, 2007, ch.11 [4] K. Wongthavarawat, and A. Ganz, Packet Scheduling for QoS Support in IEEE 802.16 Broadband Wireless Access Systems, International Journal of Communication Systems, Vol. 16, p81-96, 2003 [5] K. R. Raghu, S. K. Bose, and M. Ma, Queue Based Scheduling for IEEE 802.16 Wireless Broadband, in Proc. 6th IEEE Int. Conf. ICICS, 2007, pp. 15 [6] , , 2009 39

Slide 40

Q&A Thanks for your attention! 40