Interactive Mobile TV: Group and Resource Management

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22 November 2005 Interactive Mobile TV Group
and Resource Management Haitham
Cruickshank University of Surrey
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Introduction

• Multicast concept attracts growing attentions
  from mobile operators due to its capability of
  efficient service delivering
• Unlike unicast in which data are send to
  individual receivers, in multicast one copy of
  data is transmitted from source to multiple
  receivers.
• Unlike broadcast (such as TV service), multicast
  distribution focused on group services.
• Interworking of multicast-enabled networks is an
  interesting solution for Beyond 3G systems.
• Examples of multicast services
• Audio and video streaming such as on demand
  video and web TV/radio
• Content delivery such as electronic newspaper
  and notification system for sport news,
  up-to-date business information e.g. stock rates
• Multiplayer games

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Challenges for Multicast User Services
Content Provider
External PDN / Internet
DVB-T/H
AP
UTRAN
WLAN
SRAN
(W)
(U)
(D)
(D)
(U)
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Requirements for Successful Interworking

• Advanced resource management and session
  management functionality to achieve desired
  multicast delivery coordination.
• Mechanism that allow
• Selection of suitable delivery networks
• Selection of appropriate service flows
• Dynamically act on network conditions, e.g. load
  balancing
• Awareness of interested receivers and their
  heterogeneity expressed by receiver context
  information.
• Scalable mechanisms for network initiated
• Multicast bearer establishment and release
• Vertical network handover for groups of receivers
• Flow handover for groups of receivers

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Resource Management Conceptsfor Interworking
Networks
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Resource Management Objectives

• Provide efficient multicast services delivery in
  a heterogeneous infrastructure comprising
  multicast-enabled wireless networks.
• Provide efficient multicast services to
  heterogeneous receivers with various QoS
  capabilities and network interfaces.
• To maximize profit for the network
  operator,while respecting the users preference
  (e.g. acceptable level of delay and QoS).

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Resource Management - mechanisms

• Service Scheduling
• Batch multiple requests for the same content into
  a group for a specific batching duration and then
  serve them over one common channel
• Dynamic Access Network Selection
• Select the suitable access network and
  transmission QoS, which satisfies the users QoS
  requirements whilst offering the highest
  profit for the service provisioning

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Resource Management Architecture
Home Network
Content request
RM
MSS
Other cooperative networks
NS/QoSA
RM 3
RM 2
RM 1
Selected access network and QoS
RCC
LM
GM
service profile
user profile
RM resource manager MSS multicast service
scheduling NS network selection QoSA QoS
adaptation RCC resource cost calculation GM
group manager LM local monitor
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Service Scheduling Signalling
RM
NS QoSA
GM
ISS
User requests
Scheduling request (content and user profiles)
Service scheduling
Construct content delivery request
Content delivery request (content and user
profiles)
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Network Selection Signalling
cooperating network providers
home network provider
LM
RCC
NS QoSA
RCC
LM
RCC
LM
RCC
LM
Content delivery request
Require network status
Require network status
Network selection and QoS adaptation
Content delivery reply
Network resources reservation and configuration
for contents delivery
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Group Management Conceptsfor Interworking
Networks
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Group Management - Objectives

• Assist resource management by aggregating useful
  context information of interested receivers of a
  multicast user service.
• Provide mechanisms to implement resource
  management decisions efficiently by
• Network initiated multicast bearer
  establishment/release
• Network initiated vertical network handover for
  groups of receivers
• Flow handover for groups of receivers
• Scalable delivery of interworking signalling to
  large receiver groups.

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Group Management Architecture
Network side
User side
GMs in cooperating networks
Group manager (GM)
Signalling CH
SCF
IGMII
GMMF
NMF
Group Subscription, e.g. via HTTP
IIGI
Device Presence Service
Network entities
Resource Management
Group Manager Functional Blocks SCF Session
Control Function GMMF Group Membership
Management Function NMF Network Management
Function
Interfaces MSC Multicast Signalling
Channel IGMII Interworking GM Interaction
Interface IGII Interworking Internal Gateway
Interface
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Multicast Signalling Channel

• Motivation
• Reduce signalling cost - efficient delivery of
  control signalling for required interworking to a
  large group of receivers
• Principles
• Instead of sending separate message to every
  receiver, control signalling is delivered to a
  group via a multicast signalling channel (MSCH)
• Each user for a multicast user service subscribes
  to the IoN-MSCH for the duration of a session
• Novel mechanism for efficient receiver subset
  addressing of receivers on the IoN-MSCH to
  minimise required signalling load
• Based on context information receivers have in
  common

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Signalling Example Session Setup
Group Manager
Access Router
UE
GMMF
SCF
RM
UE
Service Announcement/Discovery
Group Subscription
IGMP join (MSC)
Scheduling and network selection
Establish control plane
ESTABLISH (IP Multicast Address, Network)
IGMP join (IP Multicast Address)
Establish user plane
IGMP join (IP Multicast Address)
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Signalling Example Vertical Handover
Group Manager
AR old
AR new
UE
GMMF
SCF
RM
UE
Load balancing decision
MIGRATE (IP Multicast Address, new Network)
IGMP join (IP Multicast Address)
Switch user plane
IGMP leave (IP Multicast Address)
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Multicast Middleware (on user terminal)

• Provides transparently a seamless multicast
  socket service to application.
• On group subscription, it starts listening to a
  multicast signalling channel to receive control
  information from group manager.
• Manages multicast session over terminal
  interfaces as requested by GM
• Establishment, release, migration of multicast
  bearers by remote subscription approach
• Flow mobility
• Forwards incoming data flows to application.

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Not Just ConceptsImplementation Demonstration
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What is required from the network to perform
interworking ?
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Implementation Demonstration Scheduling and
Network Selection

• Each group membership subscription triggers
  scheduling function
• Scheduling either size- or time-based
• When threshold is reached Network Selection is
  invoked
• GMMF provides Network Selection with user group
  and relevant context information.
• Network Selection algorithm selects appropriate
  QoS and network for each user in the group.
• Network Selection notifies Session Control
  Function in group manager to initiate session
  establishment.

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Implementation Demonstration Session Control
Signalling

• Session Control Function (SCF) determines
  subgroups based on selected networks and QoS.
• Extracts common context information for receivers
  of each subgroup and creates addressing
  expression uniquely identifying each subgroup.
• Sends a control message for establishment/release
  for each subgroup via the Interworking-MSCH for
  the multicast user service

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What is required from the terminal to perform
interworking ?
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Implementation Demonstration Bearer Setup on
Receiver

• Multicast middleware in receiver obtains control
  message via interworking-MSCH.
• Middleware evaluates addressing expression
• it joins the identified multicast group on the
  specified network interface.
• Incoming multicast session data is forwarded by
  the middleware to the application.

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Implementation Demonstration Multicast
Middleware

• Middleware for session layer functionality
• Based on TESLA toolkit (same as Migrate)
• Dynamic library interposition principle
• Code complexity 2000 LoC (Lines of Code)

Application
Multicast Middleware
Tesla
C-library/OS
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Middleware Bearer Establishment - 1
1, Gets IP multicast address/port of
Interworking-MSCH via announcement 2. Opens and
binds socket
Application
Multicast Middleware (MM)
C-library/OS
3. Multicast middleware opens real socket using
provided IP multicast address/port 4. Starts
listening to commands from group manager
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Middleware Bearer Establishment - 2
7. Starts forwarding incoming data to application
Application
Interworking-MM
C-library/OS
5. Receives establish request (IP Multicast
address/port/network)
6. Establishes multicast socket on Identified
interface for data plane
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Middleware Vertical Handover - 1
3. Still forward data from old socket until data
from new one arrives
Application
Interworking-MM
C-library/OS
1. Receives migrate request Old and new (IP
Multicast address/port/network)
2. Establishes new multicast socket on Identified
interface for new data plane
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Middleware Vertical Handover - 2
6. Application receives data from new socket
Application
Interworking-MM
C-library/OS
5. Old data plane is released
4. New data arrives
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What is the complexity to perform interworking ?
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University of Surrey Wireless Network Testbed
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Implementation Demonstration Network
Architecture
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Implementation Demonstration Network Equipment

• Network infrastructure
• 2 Cisco routers (2600 series)
• 1 GigabitEthernet Layer3 switch
• Layer 2 switches
• 1 WLAN access point
• Servers
• Interworking gateway (GM/RM)
• Streaming servers
• Web server
• Clients
• 3 Laptops with Ethernet/WLAN card
• Fedora Core 3 Linux

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Implementation Demonstration Gateway
Implementation

• Implementation language C and QT library
• Portable to any platform
• Code complexity 8000 LoC
• Features
• Multithreaded group management server
• Service Manager for service creation
• Each service provides
• its own grouping, and up to 2 different service
  flows
• scheduling (size and timeout based)
• network selection function (by the RM function)
• its own Interworking-MSCH (messages XML based)
• User context information data base and browser

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Other components

• Webserver
• Apache 2
• HTML fronted for user subscription
• Python script as subscription backend to group
  manager
• Streaming Server
• Video LAN Client (VLC) as video server
• Currently streaming UDP however RTP also possible
• User request simulation
• Python script

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Conclusions
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Resource and Group Management Conclusions

• In interworked heterogeneous wireless networks
• Resource management focuses on service
  scheduling, and network selection
• Group management focuses on aggregation of
  receiver context information to support RM in its
  decision making
• Close interaction between resource and group
  management during set-up and handover.
• Combined interworking and multicast is a
  promising solution to extended services in
  existing wireless networks.

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Thank you !