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IEEE 802.21 MEDIA INDEPENDENT HANDOVER

Title: 21-08-0230-02-mrpm-redefined-scenarios-presentation.ppt

Date Submitted: August 27, 2008

Authors or Source(s): Behcet Sarikaya (Huawei), Dennis Edwards (CoCo), Anthony Chan (Huawei), James Han (Motorola), Michael Williams (Nokia), Scott Henderson (RIM), Farrokh Khatibi (Qualcomm)

Abstract: MRPM Scenarios Presentation

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IEEE 802.21 presentation release statementsThis document has been prepared to assist the IEEE 802.21 Working Group. It is

offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein.

The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.21.

The contributor is familiar with IEEE patent policy, as outlined in Section 6.3 of the IEEE-SA Standards Board Operations Manual <http://standards.ieee.org/guides/opman/sect6.html#6.3> and in Understanding Patent Issues During IEEE Standards Development http://standards.ieee.org/board/pat/guide.html> 

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MRPM Problem Statement (1)

• With advances in devices, networks and usage models, multi-radio operation is becoming the norm for Mobile Nodes (MN).

• Each MN radio consumes power. The amount of power consumed by a radio depends on the technology and the traffic it carries.

• Example: iPhone 3G Battery Life

Voice (2G) = 600 minutesVoice (3G) = 300 minutesWeb Browsing (WiFi)* = 428 minutesWeb Browsing (Edge)* = 343 minutesWeb Browsing (3G)* = 197 minutesA-GPS = “insignificant affect”

*Anandtech \July 11th, 2008http://www.anandtech.com/gadgets/showdoc.aspx?i=3353

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MRPM Problem Statement (2)

• This is a power consumption graph of a typical isochronous traffic flow from WiFi VoIP, Interface power consumptions are not uniform.

• Even for the same technology, baseline power consumption is implementation dependent and may be non-zero, cf. Wireless Wakeups Revisited- Energy Management for VoIP over Wi-Fi SmartPhones

• All other things being equal, faster data rates are more energy efficient. http://i.cmpnet.com/wirelessnetdesignline/2008/06/atheros2-fig1.gifhttp://research.microsoft.com/netres/publications/mobisys07-cell2notify.pdf

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MRPM Problem Statement (3)• Turning off all radios conserves the most power. Putting all radios in the active

state maximizes connectivity and minimizes response time. • Battery capacity is proportional to temperature and inversely proportional to

discharge rate, charge cycle count, age, etc. The more radios that are on, the higher the discharge rate and the smaller the battery capacity. Battery graphs from.

• http://www.maxim-ic.com/appnotes.cfm/an_pk/3958

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MRPM Problem Statement (4)

• Each radio interface is independently power managed using network specific mechanisms. Power consumption optimizations of individual access technologies allow viable target services with acceptable battery life. Such optimizations are neither global nor cooperative, cf. https://mentor.ieee.org/802.21/file/08/21-08-0207-00-mrpm-power-consumptions-in-baseband-processors.ppt

• Network interface power consumption is only one aspect of system power consumption. Computational energy costs for things like packet encryption also need to be considered. Things like increased packet latency from CPU clock scaling are also important, cf. https://mentor.ieee.org/802.21/file/08/21-08-0197-02-mrpm-response-time-in-different-modes-of-operation.ppt

• The problem is to allow global policy to guide an optimal selection of operational radio interfaces that satisfies connectivity and latency requirements while minimizing MN energy consumption.

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802.21 Overview• With advances in devices, networks and usage models, multi-radio

operation is becoming the norm for Mobile Nodes (MN).• IEEE 802.21 provides an abstract set of Media Independent Handover

Services (MIH) designed primarily to support vertical handovers (across heterogeneous networks). These MIH services include handover initiation, network selection and interface activation. Handovers within a single network are most efficiently handled by the network itself, though the MIH protocol may be used to communicate among homogenous network components.

• The MIH interfaces provide a generalized framework through which disparate networks can be individually addressed and allow specifying higher level handover standards in terms of the MIH framework.

• MIH policy enforcement is explicitly relegated to a Network Selection Entity (NSE). NSE may reside on MN to support local handover policy, on the network to facilitate centralized handover policy, or cooperative with communication between client and network enabled by MIH.

• The MIH Information and Event Services inform NSE policy decisions to enable more effective handover decisions. Policy decisions are affected through the MIH Command Service.

• Designed for existing and evolving networks. Media specific changes closely follow base 802.21 MIH Protocol by increasing the breadth of the media specific interface.

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What MRPM Will Do to Help?

• Extend 802.21 to…

• Provide a standard, generalized framework as a set of power saving enablers for minimizing multi-radio power consumption

• by querying and setting the operating mode of a wireless network interface.

• allowing users of the framework to consider network throughput and energy consumption as policy inputs.

• for using MIH IS network PoA location, coverage maps and MN location information to conserve power in out of coverage areas.

• Provide a conceptual model that emulates, i.e. proxies a radio’s presence on a network while it is turned off or placed in deep sleep mode.

• Reduce the effects of frequent keep-alives by NAT/FW/VPN boxes and presence systems.

• MRPM will develop tools and improved 802.21 interfaces that will lead to next generation connection managers with improved power management capabilities. This in turn will benefit operators and mobile phone integrators, cf. https://mentor.ieee.org/802.21/file/08/21-08-0228-00-mrpm-mrpm-augmenting-a-feature-for-mih.ppt

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MRPM Framework: Get/Set Radio Operating Modes

• Abstract Radio Power Modes (ARPM) provide a mapping between an existing 802.21 Link_Action request (LINK_POWER_UP, LINK_LOW_POWER, LINK_POWER_DOWN) onto a technology specific operating mode of a radio. List of Actions may need to be extended.

• Enable power management policy enforcement.

• Each radio has an array, constructed by the MN manufacturer, containing (non-transmitting) energy consumption values for each ARPM.

• Need to extend 802.21 Link SAP to retrieve the profiles and to return, as well as set, the current ARPM values.LINK_POWER_UP = connected and active

LINK_LOW_POWER = connected and idle

LINK_POWER_DOWN = not connected

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MRPM Framework: Energy Consumption Metrics

The energy consumed by the wireless network interface module (vs. TX output power, IERP, etc.) is of primary interest to MRPM. There are many ways to express this battery drain, including bit energy cost (nJ/b) = mW * J/Ws * us/b = W*10-3 * J/Ws * s/b*10-6 = J/b*10-9 = nJ/b

These metrics allow NSE to consider network energy consumption as a policy input; all other things being equal, choose the most energy efficient network. The most energy efficient network is also likely to be the fastest one (small bit widths).

Extend MIH IS metrics to include network and link power consumption. IE_NET_DATA_POWER_LOAD value is likely to be a fixed optimal value. LINK_PARAM_GEN values are measured quantities that reflect recent network conditions.

DATA_POWER_LOAD UNSIGNED_INT(2) The type used with the IE_NET_DATA_POWER_LOAD, expressing power consumed, in mW, at the network IE_NET_DATA_RATE

Data Power Load DATA_POWER_LOAD A new value, 5, needs to be added to the list LINK_PARAM_GEN options that specifies the power consumed, in mW, at the LINK_PARAM_GEN option 0, Data Rate

Energy Consumption UNSIGNED_INT(4) A new value, 6, needs to be added to the list LINK_PARAM_GEN options that specifies the energy consumed, in nJ, during the interval used to determine the value of LINK_PARAM_GEN option 3, Throughput

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MRPM Framework:Using Location Services

•Enable the use of coverage models to leverage and expand the 802.21 IE_POA_LOCATION element.•MN must be able to tell its location relative to, and independently of, any network POA•Coverage map from MIH IS and MN location combine to avoid scanning in out of coverage areas by facilitating radio scheduling.

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MRPM in Action: Power Management in out of Coverage Areas

• A MN will have no network connection when it is first turned on or when it has moved out of the coverage range of all available networks.

• With no other knowledge, the MN must turn on all radios, to maximize the chance of finding an appropriate network to connect with. In networks other than WiMax, the radios are essentially in an Active RX mode while looking for a network.

• MRPM could turn on a radio to scan for a network and then turn it off again for some configurable interval if the scan discovered nothing.

• If MN can determine its own location then when querying the MIH IS for a list of proximate networks, an MN may specify an NGHB_RADIUS that far exceeds the range of any of its network radio interfaces. In areas of sparse network coverage an NSE may tell from the location and range data returned by the MIH IS that, upon losing connection with the current network, it will not be able to reconnect to another network for some significant time. In this case, the NSE may turn off the radio on receipt of a LINK_DOWN event

• Should an MN determine that, based on the MIH IS coverage map, it is approaching the coverage area of a new network then it could turn on the appropriate radio. A LINK_DETECTED event will be generated when the network is discovered and a LINK_UP event will be generated when the network is joined. At such time the network coverage map may be refreshed by the MIH IS

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MRMP Framework:Conceptual Model for Emulation

• 802.21 is designed for existing and evolving Networks

• MRPM will extend Media Independent Command Service (MICS) so that emulation/proxying of an interface is possible

• The extension will make it appear that a powered down radio on the MN has actually joined the candidate network. It thus will maximize the candidate network availability while minimizing MN battery drain.

• CS extensions over MN-PoS communication will be defined• The emulation of certain functions (e.g., MN location

updates) are technology specific operations• MRPM will be used with any higher layer mobility

protocols in use such as Proxy Mobile IP, Mobile IP or SIP that are already widely deployed on several networks

• Some of the emulation scenarios are different in the case of WiFi interface

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Emulation Scenarios

• Location Update (LU) Scenario enables MN location updates to make it appear that a powered down radio on the MN is roaming and updating its location

• Idle Mode Entry (IME) Scenario makes it appear that a powered down radio is going to the idle mode

• Waking up powered off radio using active radio (WU) Scenario enables the termination of emulation/proxy

• All of these scenarios can be realized using technology dependent signaling

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Emulation Scenario: Idle Mode Entry

• After completing a network operation, the MN may decide that it wants to turn off the radio and replace it with a proxy session. This is accomplished by using an extended CS message to the PoS.

• Technology dependent signaling for idle mode entry can be done by the interface itself. After the request is confirmed, the radio is powered off and a proxy session is established over the active interface

• Assuming simultaneously overlapping coverage, all but one active radio may be replaced by a proxy service.

• Depending on the amount and kind of data passing through the current network to the MN, the active radio interface may be placed in a low power state other than off.

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Emulation Scenario: Location Update Using Active Interface

• While a proxy session is active, the MN may move from one paging/tracking area to another on the same network. When such a situation is identified using location services and coverage maps, the NSE updates the paging/tracking area with the PoS using the active interface.

• In some cases it may be better to enable pre-authentication (Security SG of 802.21) as well as location update. Pre-authentication authenticates MN using the active interface.

• Should mobility cause the MN to switch to a third network then the NSE will use an extended CS message to the PoS, notifying it of the network change.

• Should the MN leave the coverage area of the proxy network then it will notify this to the PoS.

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Emulation Scenario: Waking Up Powered-off Interface Via the Active

Interface• A data or voice call generates cellular paging message for the

powered off interface which is being proxied

• PoS initiates the wake-up message towards NSE using the active interface

• NSE has different choices and selects one based on the policy:• Wakes up the turned off radio and have it replace the proxy

on the candidate network by sending an extended CS message to the PoS.

• Wakes up powered-off WiFi radio

• Once the radio has replaced the proxy on the candidate network the proxy session ends. The NSE may switch to the new radio or decide to continue dual radio operation.

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Keep Alive Scenario: NAT/FW/VPN

• NAT/FW/VPN boxes send frequent keep alive messages that wake up a dormant MN

• Presence systems like IM/Chat also have frequent keep alives

• MRPM will extend MIH IS and ES to handle “keep alives” without unnecessarily waking the MN, cf. https://mentor.ieee.org/802.21/file/08/21-08-0229-00-mrpm-mrpm-power-save-topics.ppt

• MRPM Solution Scenarios:• New MIH SAP local services for coordination and control of

keep-alive transmissions• Discover presence of timer values for NAT/FW/VPN/MIP

via IS or ES• Configure timers to synchronize them, via CS or new service• Proxy keep-alive services up or downstream

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Considerations for 802.11

• WiFi interface consumes much power even in power save mode:

• WiFi interface is the most power efficient radio during an active VoIP call:

• https://mentor.ieee.org/802.21/file/08/21-08-0158-02-mrpm-pm-states-in-single-radio-technologies.ppt

• Powering-off WiFi interface and waking it up upon a voice/data call will save most power

• For WiFi there is no need to update the location

• For WiFi there is no need to do idle mode signaling

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Considerations for 802.16

• TBD

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NCMS Extension

Network Control and Management System

Service Flow Id /Connection Id Management Services

RF Transmission and Synchronization Services

AAA Services

Network Address Management Services

Mobility Management Services

Gateway and Router Services

Paging Services Idle Mode Services

Network Management Services

Multimedia Session Management Services

Inter-working Services

Security Services

Media Independent Handover Function Services

Radio Resource Management Services

802.16 Amendments

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Considerations for non-802 networks

• TBD

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Thank you.

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backup

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3G iPhone Battery LifeApple iPhone 3G Battery Life

Standby = 18000 minutesAudio playback = 1440 minutesVideo playback = 420 minutesVoice (2G) = 600 minutesVoice (3G) = 300 minutesWeb Browsing (WiFi)* = 428 minutesWeb Browsing (Edge)* = 343 minutesWeb Browsing (3G)* = 197 minutesA-GPS = 15 mW at 1Hz duty cycle (map updates every second) *Anandtech \July 11th, 2008 Battery graphs from. WiFi VoIP power consumption graph.

http://www.anandtech.com/gadgets/showdoc.aspx?i=3353

http://www.maxim-ic.com/appnotes.cfm/an_pk/3958

http://www.wirelessnetdesignline.com/208401866;jsessionid=WG0L4NMLRAIOKQSNDLPCKHSCJUNN2JVN?printableArticle=truehttp://www.windowsfordevices.com/news/NS5361429977.html

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Useful Reading

http://www.freepatentsonline.com/7133374.html

• http://www.cs.toronto.edu/~delara/courses/csc2228/papers/coolspots.pdf

• http://www.wipo.int/pctdb/en/wo.jsp?wo=2007019556

• http://www.monarch.cs.rice.edu/monarch-papers/icnp2002.pdf

• http://citeseer.ist.psu.edu/sconyers98examination.html

• http://www.csr.com/egps/introduction.htm