1 A new QoS Architecture for IEEE and Spec. Instruction Speaker: Ming-Chia Hsieh Date:2005/05/03

2 Outline Introduction Spec. New Qos Architecture a brief introduction Conclusion

3 Introduction – Fast Deployment – Cost Savings – Support Quality of Service

4 FRAMEWORK

5 Outline Introduction Spec. New Qos Architecture Conclusion

6 Spec.

7 Communicate path – Uplink Channel (SS to BS)— TDMA UL-MAP – Downlink Channel (BS to SS) Broadcast

8 Spec. TDMA mini-slots called Time-Division Multiple Access

9 TDD frame structure Symbol Rate ： range 10~32M Baud, increments of 100k Baud

10 Spec. Uplink Channel – Uplink Channel Descriptor Configuration Change Count – Determine whether the content is changed Mini-Slot Size – Units of Physical Slot, Allowable n=2 m Uplink Channel ID – Arbitrarily Chosen by the BS – Unique within the MAC-Sublayer domain

11 Spec Uplink Channel (Cont.) – Uplink Map (UL-MAP) Allocates access to the uplink channel

12 Step to enter the network BS SS SCAN for a downlink channel Downlink channel parameter DL-MAP DCD Adjust local parameter Authorize/key exchange Management msg SBC-REQ Control by BS IP Establish time of day Configuration information REG-REQ

13 Channel Access BS SS Downlink channel DATA DL-MAP Uplink Channel UL-MAP Time slot DATA

14 Spec. Downlink Channel – Downlink Channel Descriptor (DCD) Transmitted by the BS Define the characteristics of a downlink physical channel

15 Spec. Downlink Channel – Downlink Map Parameter PHY Synchronization DCD Count – Match the DCD Base Station ID – 48-bit

16 Spec. Qos ( Quality of Service ) – Associate a packet with a service flow – Service Flow ： unidirectional flow of packets that provides a particular Qos

17 Spec. Support Quality of Service Unsolicited Grant Service—UGS Real-Time Polling Service—rtPS Non-Real-Time Polling Service—nrtPs Best Effort—BE

18 Spec. QoS types – UGS Real-time service flows Periodic, fixed size grants Avoid overhead and latency of frequent SS redundant Meet the continuous need of service flow T1 / E1 / VoIP

19 Spec. Qos Types (Cont.) – rtPS(Real-Time Polling Service) Real-time service flows Variable size data MPEG

20 Spec. QoS types – nrtPS Non real-time service flow Variable size data – BE ﹝ Best Effort ﹞ Efficient service to best effort

21 Spec. Bandwidth allocation and request – Each SS is assigned 3 dedicated CID for different level of QoS – Incompressible constant bit rate UGS can’t reallocate bandwidth – DAMA services are given resources on a demand assignment basis

22 Spec. Mode of grant of bandwidth request – GPSS ﹝ Grant per Subscriber Station Mode ﹞ Bandwidth request are addressed to SSs Smaller UL maps Allow more intelligent SS – GPC ﹝ Grant per Connection ﹞ Bandwidth request are addressed to CIDs – 這二個 MODE 在 a 中刪除了

23 Outline Introduction Spec. New Qos Architecture Conclusion

24 Qos of IEEE Admission Control undefined by IEEE Uplink Bandwidth Allocation Scheduling Uplink Scheduling for UGS defined by IEEE Uplink scheduling for rtPS, nrtPS and BE service undefined by IEEE Traffic Connection Classifier UGSrtPSnrtPSBE scheduler Connection Request Connection Response BW Request Message Data packets

25 New Qos Architecture Admission Control Uplink Bandwidth Allocation Scheduling Data Packet Packet Module Traffic Management Table Packet Allocation Module Data Packet Analysis Module Traffic Connection Classifier UGSrtPSnrtPSEE Scheduler Connection Request Connection Response Data packets BW request Message

26 New Qos Architecture Before establish connection SS set connection request to BS Admission control part of the BS decides to accept or reject BS provide necessary information to SS

27 New Qos Architecture After establish Enforce the traffic on the contract BS update the traffic management table BS generate UL-MAP in downlink subframe SS transmits packets according to the UL- MAP

28 New Qos Architecture Uplink Scheduler of SS – Transmit data PDU using uplink data slot granted by BS. – UGS append virtual packet arrival time of rtPS – DPAM ( Data Packet Analysis Module ) receive rtPS deadline information from SS. – Packet deadline=arrival time + maximum delay requirement of the connection

29 New Qos Architecture Uplink Scheduler of SS (Cont.) – nrtPS uses either contention-free or contention mod. – BE uses only contention mode – BS controls contention mini-slot size in frame.

30 New Qos Architecture Uplink Bandwidth Allocation Scheduling – DPAM of BS separates UGS data and virtual packets arrival time of rtPS – Traffic Management Module manages the information to decide the Poll order of next time

31 New Qos Architecture Backoff Procedure – BS broadcast a common back-off window size “B” – SSs will randomly choose a reservation slot numbered between 1 and B to transmit its request

32 Channel utilization analysis K Classes Arrival events are mutual independent C denotes the server capacity and channel utilization for each class I C=p 1 +p 2 +p 3 +……p i,C<=1

33 Channel utilization analysis λK ： offered load for class K E[τK] ： average service time for class K

34 Simulation parameters

35 Simulation a. no limit bandwidth Offered Load Channel Utilization

36 Simulation b. fixed quota Offered Load Channel Utilization

37 Simulation c. different data size (100 byte) Offered Load Throughput

38 Simulation d. different data size (150 byte) Offered Load Throughput

39 Simulation e. different data size () Offered Load Throughput

40 Conclusions The main target of WiMax is to replace the so called last mile. It can advance a lot in the future. Whether it can make it or not is still unable to answer. But many companies have announced to support it, especially INTEL

41 Reference IEEE Standards Performance Analysis of the IEEE Wireless Metropolitan Area Network, (DFMA’05)

42 END

43 New Qos Architecture Example – Backoff window size=B – Probability of choose a given slot=p=1/B – The probability of a given slot is not selected P ns =(1-p) N – System throughput is P th =Np(1-p) N-1

44 Spec. Provision of Qos – Based on the “Envelopes” – Parameters ProvisionedQosParamSet A set of external QoS parameters provided to the MAC AdmittedQosParamSet A set of QoS parameter for which the BS and possibly the SS are reserving resource ActiveQosParamSet A set of QoS parameters that reflect the actual service being provided to the associated active service flows