context-aware resource management for mobile servers c. ververidis, e.c. efstathiou, s. soursos and...
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Context-Aware Resource Management for Mobile Servers
C. Ververidis, E.C. Efstathiou, S. Soursos
and G.C. Polyzos
Mobile Multimedia LaboratoryDepartment of Computer Science
Athens University of Economics and Business
10434 Athens, Greece
http://mm.aueb.gr/ 10th HP-OVUA Workshop, Geneva, July 6-9, 2003 2
Outline
Technology Trends Location-Based Services The Service Provision Environment Network Architecture Implementation Mechanisms
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Technology Trends
Computing and Telecommunication technologies convergence– From the WWW to the Mobile Web– Need for anytime anywhere access to information
Abundant access bandwidth, storage, and processing power at the edges of the network– Emergence of low-cost wireless access technologies, e.g.
• IEEE 802.11• Bluetooth
– Emergence of Peer-to-Peer (P2P) service models “Next-generation” terminals
– Small devices with server-like features and capabilities
http://mm.aueb.gr/ 10th HP-OVUA Workshop, Geneva, July 6-9, 2003 4
Location-Based Services (LBS)
Mobile Web and LBS are evolving together The Case for LBS
– Innovative, useful services• attract new customers
• enhance customer loyalty to the provider
– Revenue increase due to traffic generated by the use of such services
Traditional business models for LBS vary depending on the number of participants in the LBS value chain
LEVEL OF LBS REVENUE SHARING
Mobile operator provides connectivity, positioning
and content
Mobile operator provides connectivity. Positioning
and content are provided by external providers
Min Max
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New LBS Model
Mobile Operator provides– Connectivity– Positioning Technologies– Service Advertisement & Discovery Infrastructure
Mobile Subscribers provide– Content, possibly sensitive to time and space
changes Operator’s network externalities depend
heavily on customers’ content
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Service Provision Environment
Wireless Access Provider (WLAN or UMTS)– Access Point (AP) or Base Station (BS) covering an area
of interest Some Mobile Subscribers can act as servers and
offer content– Mobile devices with attached digital cameras
Content sensitive to place and time– e.g. photo-series or low length/quality videos that provide
information on the traffic conditions in the coverage area Content available only in the specific coverage area
– No value outside due to space and time sensitivity and the high costs of transferring it
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Assumptions
Network operator has the infrastructure for Service Advertisement and Discovery– Centralized or de-centralized
Network operator possesses a positioning technology– From COO and OTDOA-IDL to GPS– We use a simple approach based on SINR values
measured from the AP
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Example: Traffic Conditions
AP
Message from M1
Each mobile server– with the appropriate equipment
(e.g. photo camera)– can offer (to other mobile
subscribers) traffic condition information (including photos or short videos)
The service is only available within the AP’s coverage area
http://mm.aueb.gr/ 10th HP-OVUA Workshop, Geneva, July 6-9, 2003 9
Environment Set-up
AP
AP
AP AP
Single AP Coverage area spreads
along a main traffic road Subscribers are informed
about the traffic condition of the specific road
Extension: Multiple APs Covering and providing
traffic information for many roads
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Architecture’s Goals
Give the mobile server the appropriate uplink bandwidth to serve the requests
Provide the mobile subscribers/clients the appropriate transfer rate according to their relative position to the mobile server
Keep the content inside the coverage area by favoring content exchanges between mobile servers
http://mm.aueb.gr/ 10th HP-OVUA Workshop, Geneva, July 6-9, 2003 11
Architecture
Differentiate uplink rates for each server-client pair and according to their relative position
UMTS:– At the Radio Resource Management (RRM) located at the
Radio Network Controller (RNC) IEEE 802.11 WLANs:
– Software upgrades at the Access Point to support advanced queuing disciplines (other than FIFO)
Mobile Server Mobile Client
Inner Circle
Middle Circle
Outer Circle
Inner Circle 10kbps 10kbps 20kbps
Middle Circle 10kbps 20kbps 50kbps
Outer Circle 20kbps 20kbps 50kbps
AP
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Implementation
Need for a QoS context-aware scheme Two approaches:
– LBS-DF• Based on IETF Differentiated Services
– LBS-IS• Based on IETF Integrated Services
Different implementation for each technology– UMTS vs. IEEE 802.11 WLAN
http://mm.aueb.gr/ 10th HP-OVUA Workshop, Geneva, July 6-9, 2003 13
LBS-DF Approach
We define 3 QoS classes (from 1 to 3) – Class 3 is the class with the higher priority– Different transmission rates for each class
3 flow-serving queues at AP with different serving rates Extra packets are dropped or treated as in Assured Service
class AP changes the QoS class according to the power readings
and transparently to the mobile userMobile Server Mobile Client
Inner CircleMiddle Circle
Outer Circle
Inner CircleQoS Class
1QoS Class 1
QoS Class 2
Middle CircleQoS Class
1QoS Class 2
QoS Class 3
Outer CircleQoS Class
2QoS Class 2
QoS Class 3
http://mm.aueb.gr/ 10th HP-OVUA Workshop, Geneva, July 6-9, 2003 14
LBS-IS Approach
Several queues at AP, each serving a flow for a mobile server – client session
A “Scheduler” module keeps an NxM array– N: number of mobile servers– M: number of mobile subscribers
CAC in order not to exceed total available bandwidth– ~5 Mbps for 802.11 WLANs and 2 Mbps for UMTS
Goal:– Maximize the number of
completed file transfers
Mobile Clients Mobile Servers
A B C D
A X10kbp
s50kbp
s20kbps
C 10kbps30kbp
sX 50kbps
D100kbp
s20kbp
s40kbp
sX
http://mm.aueb.gr/ 10th HP-OVUA Workshop, Geneva, July 6-9, 2003 15
UMTS Issues
Throughput that a mobile server has on the uplink is based on the chip rate received from the BS
Differentiating the chip rate differentiating the transmission rate
Proposed QoS classes are different from the UMTS QoS classes– UMTS QoS classes: generic QoS, same for all
traffic in our service environment– Proposed QoS classes: lower-level QoS
http://mm.aueb.gr/ 10th HP-OVUA Workshop, Geneva, July 6-9, 2003 16
IEEE 802.11 WLAN Issues
Upcoming 802.11e standard:– A new MAC layer algorithm (Hybrid Coordination
Function – HFC)– WLAN AP acts as a point coordinator and polls
mobile stations for data, similar to the UMTS mechanism
– Use of CF-Poll messages in HFC:• Expected start time of transmission• Maximum duration of transmission
http://mm.aueb.gr/ 10th HP-OVUA Workshop, Geneva, July 6-9, 2003 17
Summary
New mobile technologies and LBS are forming a new business model for service provision
Mobile Servers offering content sensitive to place and time changes
Network architecture with the AP configuring mobile server’s uplink bandwidth– DiffServ vs. IntServ approach– UMTS vs. IEEE 802.11 WLANs
Thank you!
C. Ververidis, E.C. Efstathiou, S. Soursos and G.C. Polyzos
Mobile Multimedia Laboratory
Department of Computer Science
Athens University of Economics and Business
10434 Athens, Greece