Transcript 21-04-0035-00-0000-Layer2_5_concept

May 10-14, 2004
doc.: IEEE 802.21-xxx
Defining Layer 2.5
Alan Carlton
Interdigital Communications
[email protected]
Submission
Slide 1
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
Objectives
 To stimulate a discussion on the preferred 802.21
Mobility Architecture
 To stimulate a discussion on the scope of 802.21
 To review Typical Mobile System architecture
approaches as they may pertain to the broad objectives
of 802.21
Submission
Slide 2
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
Mobile System Terminology Used in this Presentation
 Two key modes exist for typical mobile systems - IDLE mode and CONNECTED mode:
 IDLE mode (STA) characteristics
 No User service, monitoring of paging channels, available service request channels
 100% of Receiver available for Downlink Measurements
 Background coordination, unscheduled AP/technology reselection
 CONNECTED mode (STA) characteristics
 Active User service (e.g. a call), Handover possible
 Limited Receiver availability for measurements (User service takes priority)
 Fully Coordinated, scheduled AP/technology handover
 Selection:
 Prior to entering IDLE mode (e.g. at Power up) the STA must perform selection in order to determine the best
AP and technology available for service
 Reselection:
 While in IDLE mode (i.e. No User service) the STA must continuously examine neighbor AP (and different
technology AP). Upon determination of a ‘better’ AP the STA will transition over to the new AP
 Handover
 While in CONNECTED mode (i.e. Active User Service) a handover occurs upon transition from one AP to
another AP (possibly using a different technology) offering significantly better service. In the ideal case this
transition will occur without noticeable interruption of the Active User Service.
Submission
Slide 3
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
The Cellular Mobility Model
Full Mobility Support
e.g. Switch,
Server
Network
Handover
Policy
Function
e.g. 2G BSC,
3G RNC
Radio Network
Semi-Static Frequency
Assignments
GSM/900
GSM900
GSM900
AP
GSM1800
AP
AP
GSM900
AP
AP
e.g. GSM
Base Station
AP
AP
EDGE
FDD
e.g. FDD
Node B
e.g. 2G MS,
3G UE
Cellular STA
Centralized Radio Resource Management Approach
Submission
Slide 4
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
The Cellular Mobility Model (Continued)
 Radio Network Characterization:
 Centralized RRM approach (Semi-Static Frequency assignments in each AP)
 Some Radio Planning Required
 IDLE Mode Operation:
 Intra-technology (e.g. GSM to GSM)
 AP Selection/Reselection decision made in STA supported by System information broadcast by the
Handover Policy function (Policy defined in the Handover Policy function)
 Inter-technology (e.g. GSM to FDD/WCDMA)
 AP Selection/Reselection decision made in STA supported by System information broadcast at the Handover
Policy function (Policy defined in the Handover Policy function)
 CONNECTED Mode Operation:
 Intra-technology
 AP handover decision made in the Handover Controller function supported by measurements made by the
STA and sent to the Handover Policy function via L3 signaling (Policy defined in the Handover Policy
function)
 Inter-technology
 AP handover decision made in the Handover Policy function supported by measurements made by the STA
and sent to the Handover Policy function via L3 signaling (Policy defined in the Handover Policy function)
Submission
Slide 5
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
The WLAN Mobility Model - Current
Limited Mobility Support
e.g. Gateway,
Router
Network
Radio Network
Dynamic Frequency
Assignments
802.11b
802.11a
802.11
AP
802.11a
AP
AP
802.11
AP
AP
AP
802.16
AP
802.11n
iBook
IEEE 802.X STA
Distributed Radio Resource Management Approach
Submission
Slide 6
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
The WLAN Mobility Model (Continued)
 Radio Network Characterization:
 Distributed RRM approach (Dynamic Frequency assignments in each AP)
 Radio Planning Not Required
 IDLE Mode Operation:
 Intra-technology (e.g. 802.11a to 802.11a)
 AP Selection/Reselection decision made autonomously in STA (Policy defined in the STA)
 Inter-technology (e.g. 802.11 to 802.16)
 SELECTION/RESELECTION NOT STANDARDIZED – SCOPE OF 802.21
 CONNECTED Mode Operation:
 Intra-technology
 HANDOVER NOT STANDARDIZED – SCOPE OF 802.21
 Inter-technology
 HANDOVER NOT STANDARDIZED – SCOPE OF 802.21
General Scope of 802.21
Submission
Slide 7
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
STA ONLY
DISTRIBUTED
Handover
Policy
Function
e.g. Gateway,
Router
Network
CENTRALIZED
Handover
Policy
Function
Option A
SYSTEM
Enhanced Mobility Support (802.21)
The WLAN Mobility Model – Enhanced (802.21)
Option B
Radio Network
Dynamic Frequency
Assignments
802.11b
802.11a
802.11
AP
802.11a
AP
AP
802.11
AP
AP
AP
802.16
AP
802.11n
iBook
IEEE 802.X STA
Two Basic Options Are Considered
Submission
Slide 8
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
Option A & Option B Definition
 IDLE Mode Operation:
 Intra-technology (e.g. 802.11a to 802.11a)
 AP Selection/Reselection decision made autonomously in STA (Policy defined in the STA)
 Inter-technology (e.g. 802.11 to 802.16) [SCOPE OF 802.21]
 Option A: AP Selection/Reselection decision made autonomously in STA (Policy defined in the STA)
 Option B: AP Selection/Reselection decision made in STA supported by System information broadcast at
the Handover Policy function level (Policy defined in the Handover Policy Function)
 CONNECTED Mode Operation:
 Intra-technology [SCOPE OF 802.21]
 Option A: AP handover decision made autonomously in STA (Policy defined in the STA)
 Option B: AP handover decision made in the Handover Policy function supported by measurements
made by the STA and sent to the Handover Policy function via new signaling mechanisms (Policy defined in
the Handover Policy Function)
 Inter-technology [SCOPE OF 802.21]
 Option A: AP handover decision made autonomously in the STA (Policy defined in the STA)
 Option B: AP handover decision made in the Handover Policy function supported by measurements
made by the STA and sent to the Handover Policy function via new signaling mechanisms (Policy defined in
the Handover Policy Function)
Submission
Slide 9
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
Option A: DISTRIBUTED Handover Policy Function
MAC
Sublayer
PLCP
Sublayer
PMD
Sublayer
MAC
Sublayer
ME
Physical
Sublayer
ME
Handover Policy Function
802.11 Model
Local
MIB
 Intra/Inter Technology Reselection
decision made autonomously by the STA
 Adequate but sub-optimal solution
 Intra/Inter Technology Handover decision
made autonomously by the STA
 Slow Handover Solution /Really just an
extension of Reselection and would be
characterized as such in a typical Mobile
system
 Break and then Make strategy (Resource
availability not guaranteed)
 Adequate solution for non real-time
services
 Unacceptable solution for real time
services (such as voice)
 Poorly scaleable solution
STA Functional
Architecture Concept
Option A Provides a Very Limited Mobility Solution
Submission
Slide 10
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
Option B: CENTRALIZED Handover Policy Function
 Intra/Inter Technology Reselection
decision supported by System Information
Handover
System Info
Measurements
 Optimal solution
MAC
Sublayer
PLCP
Sublayer
PMD
Sublayer
MAC
Sublayer
ME
Physical
Sublayer
ME
Layer 2.5 Signaling/Control
Function
802.11 Model
System
HPF
 Intra/Inter Technology Handover decision
coordinated by RPF and supported by
measurement reports and System
signaling
 Fast Handover Solution
 Make and then Break strategy (Resource
availability is guaranteed)
 Adequate solution for non real-time
services
 Acceptable solution for real time services
(such as voice)
 Easily scaleable solution
STA Functional
Architecture Concept
Option B Provides a Full Mobility Solution – Typical
Mobile System Architecture Approach
Submission
Slide 11
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
Typical Mobile System Architecture compared to 802.X
Network
GPRS (2G) STA
Mobility
Protocol (MM)
IP
Convergence
GSM RR
3GPP (3G) STA
IP
Mobility
Protocol (MM)
Convergence
3G RRC
GSM 04.18
IEEE 802.xx STA
e.g. Mobile IP
Layer 2.5
3GPP 25.331
IP
Convergence
IEEE 802.21
Physical
Data Link
IEEE 802.2
RLC
RLC
Transparent
Mode
Option
MAC
Physical
LLC
Transparent
Mode
Option
MAC
User Plane
Control Plane
Physical
Transparent
Mode
Option
MAC
User Plane
Control Plane
Physical
IEEE 802.3,11,16…
In a Full Mobility Solution Layer 2.5 is a key enabler
Submission
Slide 12
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
Key Protocol Functions






Mobility Protocol
Resource Control Protocol
(e.g. GSM-MM/MAP, Mobile IP…)
(e.g. GSM-RR, 3GPP RRC, L2.5?)
Discovery
Registration
Tunneling
Termination (or Paging)
Handover at Network Level
Security








System Information
Termination (or Paging)
Cell Selection/Reselection
Establishment
Release
Measurement Reporting
Power Control
Handover at Radio Level
Both Functions are required in order to support a Full
Mobility Solution
Submission
Slide 13
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
Example: End to End Functional Configuration
CENTRALIZED
Handover Policy
Function
802.11
Network
iBook
AP
802.11a
802.11a
AP
IEEE 802.X STA
e.g. Gateway,
Router
AP
Network/Radio Network Functions
Higher Layers
Higher Layers
Mobility Protocol
Mobility Protocol
Layer 2.5
Layer 2.5
LLC
Link Layer
MAC
MAC
Physical
Physical
U-Plane
U-Plane
Station Function
Handover
Policy
Function
Lower Layers
Lower Layers
The RHF may be defined as logical functional entity
Submission
Slide 14
Alan Carlton, Interdigital Communications
May 10-14, 2004
doc.: IEEE 802.21-xxx
Conclusions
 The Option B architecture with a centralized Handover Policy Function would seem to
be the most promising approach and is recommended.
 In order to provide a full mobility solution both Radio Mobility (e.g. GSM RR) and
Network Mobility (e.g. Mobile IP) protocol functionality is required in the system.
 Layer 2.5 is a key enabler in a full mobility solution.
 In order to support the Option B Architecture 802.21 should define a Layer 2.5
Signaling and Control Protocol with some similar properties to RR style protocols
currently used in typical Mobile systems.
 The Handover Policy Function may be defined as a logical entity. It is not necessary to
define any restrictions in the Standard on its location in a physical implementation
though some recommendations may be made if valuable.
 The Option B architecture closely maps to well proved typical Mobility System
architectures and will simplify future advanced interworking scenarios unanticipated at
this time (e.g. tightly coupled handover).
 The Centralized Handover Policy Functional architecture may be easily extended to
support Wireless to Wired interworking scenarios e.g. the Handover policy upon
connecting a Wireless device to a Wireline system may be automatic handover.
Submission
Slide 15
Alan Carlton, Interdigital Communications