wimax - hybrid scheduler
Post on 09-Apr-2018
216 Views
Preview:
TRANSCRIPT
-
8/8/2019 WiMAX - Hybrid Scheduler
1/24
QoS Assured Simple Hybrid Uplink Scheduler
for WiMAX Networks
Perumalraja Rengaraju, Carleton University, Canada
Chung-Hong Lung, Carleton University, Canada
Anand Srinivasan, EION wireless Inc., Canada
1
-
8/8/2019 WiMAX - Hybrid Scheduler
2/24
Presentation outline
Project goal
Introduction to WiMAX networks
Existing Scheduler Analysis
Proposed solution and Simulation results
2
-
8/8/2019 WiMAX - Hybrid Scheduler
3/24
Project goal
To design an Uplink scheduler which assure QoS for all service classes /
Application
The design should be very simple to implement for any real-time devices
Whether any of the homogeneous scheduler meet the requirements?
No..
Design a hybrid uplink scheduler to meet the requirements
QoS assurance and Simple in design
3
-
8/8/2019 WiMAX - Hybrid Scheduler
4/24
Introduction to WiMAX networks
In 2004, Fixed WiMAX (IEEE 802.16d) network was introduced. Aim of thisnetwork is to provide the broadband wireless for Fixed and nomadic users.
In 2005, Mobile WiMAX (IEEE 802.16e) network was introduced. It adds the
mobility, improved features (multicast broadcast services MBS) and
improved security support
In the middle of 2009, multihop WiMAX (IEEE 802.16j) network was
introduced. It extends the coverage region by introducing relay station (RS).
End of 2010, multihop WiMAX with Advanced Air Interface (IEEE 802.16m)is expecting to be released and the practical implementations are from 2011
onwards. It supports high bandwidth and mobility
4
-
8/8/2019 WiMAX - Hybrid Scheduler
5/24
WiMAX IP based Network Architecture
IEEE 802.16e Network(Point-to-Multi Point)
IEEE 802.16j and IEEE 802.16mmultihop Network
5
-
8/8/2019 WiMAX - Hybrid Scheduler
6/24
Protocol stack
6
-
8/8/2019 WiMAX - Hybrid Scheduler
7/24
Frame Format of IEEE 802.16e (OFDMA TDD)
7
-
8/8/2019 WiMAX - Hybrid Scheduler
8/24
Scans downlink channel
Obtain parameters
Initial ranging
Basiccapabilities exchange
Authentication & Authorization
Registration & IP Connect
Create connection)
Security Association
synchronized
Not synchronized
Initial Ranging slot identified
Wait in the same state
success
failed
failed
success
success
success
failed
failed
Data transfer
success
success
failed
MS Network entry (connectivity) - PMP
8
-
8/8/2019 WiMAX - Hybrid Scheduler
9/24
Service Provisioning and Service flow creation
Customer subscribes to the service, tells the service flow information including the number of
UL/DL connections with the data rates and QoS parameters, along with what kindof applications (e.g., Internet, voice, or video), intends to run.
The service provider pre-provision the services by entering the service flow information into the Service
Flow database.
After completing the MS/SS network entry procedure, the BS will downloadthe service flow information from the Service Flow Database (AAA server)
BS will use a Dynamic Service Addition (DSA) message to create service
flows with the pre-provisioned service flow information.
9
-
8/8/2019 WiMAX - Hybrid Scheduler
10/24
Service classes and its QoS Parameters
Unsolicited Grant Service (UGS)
Maximum Sustained Traffic Rate, Maximum Latency, Tolerated Jitter, and
Request/Transmission Policy
Extended Real-Time Polling Service (ertPS)
Maximum Sustained Traffic Rate, Maximum Latency, Tolerated Jitter, and
Request/Transmission Policy
real-time Polling Service (rtPS) Minimum Reserved Traffic Rate, Maximum Sustained Traffic Rate, Maximum
Latency, and Request/Transmission Policy
non-real time Polling Service (nrtPS)
Minimum Reserved Traffic Rate, Maximum Sustained Traffic Rate, Traffic Priority,
and Request/Transmission Policy Best Effort service (BE)
Maximum Sustained Traffic Priority, and Request/Transmission Policy
10
-
8/8/2019 WiMAX - Hybrid Scheduler
11/24
Service Provisioning UGS
11
-
8/8/2019 WiMAX - Hybrid Scheduler
12/24
Service Provisioning rtPS
12
-
8/8/2019 WiMAX - Hybrid Scheduler
13/24
Service Provisioning nrtPS
13
-
8/8/2019 WiMAX - Hybrid Scheduler
14/24
Service Provisioning BE
14
-
8/8/2019 WiMAX - Hybrid Scheduler
15/24
Service flow provisioning for the subscriber
15
-
8/8/2019 WiMAX - Hybrid Scheduler
16/24
Admission Controller
In real time, the admission controller allocates resource for the Minimum reserved rate.UGS (min. resv. rate= max. sustained traffic), BE (min. resv. rate=0)
Proposed Admission controller
BE min. resv. rate= R* max. sustained rate
16
-
8/8/2019 WiMAX - Hybrid Scheduler
17/24
Bandwidth request, allocation & Scheduling
Bandwidth request
Unicast and multicast polling mechanism
Contention based bandwidth request
Piggyback a BW request message on a data packet.
Grants / allocation
Grant Per Subscriber Station (GPSS)
Grant Per Connection (GPC)
Downlink Scheduling (scheduler resides in the BS)
Since BS knows all traffic information of downlink data for all SSs. the design
of downlink scheduling is simpleUplink Scheduling
Uplink scheduler resides in the SS effectively allocate the available OFDMA
resource to meet the required QoS for each services
-
8/8/2019 WiMAX - Hybrid Scheduler
18/24
Scheduling Algorithms - Analysis
Schedulers can be classified into channel aware and channel un-aware.
They are further classified into Homogeneous and Hybrid schedulers
Hybrid schedulers combines more than one homogeneous schedulers
Real time
Scheduler
-
8/8/2019 WiMAX - Hybrid Scheduler
19/24
Proposed Scheduler
Hybrid Scheduler. It Combines Priority and EDD scheduling algorithm
Design of the scheduler is very simple. Easy to implement in real-time devices.
19
-
8/8/2019 WiMAX - Hybrid Scheduler
20/24
System Parameters and Traffic Model
20
-
8/8/2019 WiMAX - Hybrid Scheduler
21/24
Simulation results Throughput performance
21
-
8/8/2019 WiMAX - Hybrid Scheduler
22/24
Simulation results Delay Performance
22
-
8/8/2019 WiMAX - Hybrid Scheduler
23/24
Conclusion
Design of the scheduler is simple to implement in real time devices
It eliminates the drawback of real time priority scheduler
It guarantee the delay performance for all service classes
Even though throughput of rtPS and nrtPS is reduced, still it guarantee
the minimum reserved rate.
Here, the admission controller designed in a such a way to restrict the
number BE connections to guarantee the QoS for all service classes.
23
-
8/8/2019 WiMAX - Hybrid Scheduler
24/24
Reference
24
top related