IEEE 802.21 MEDIA INDEPENDENT HANDOVER Title: Multi-Radio Power Conservation Management Date Submitted: January 16 2009 Presented at IEEE 802.21 session #30 in Los Angeles Authors or Sources: Kevin Knoll, Dennis Edwards, Behcet Sarikaya, Junghoon Jee, Anthony Chan Abstract: MRPM Tutorial 21-09-0004-00-mrpm

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Multi-Radio Market is happening now The market is seeing the introduction of many dual-radio devices. For Example: GSM/WiFi and CMDA2000/WiFi phones EV-DO/WiMax on Cardbus EV-DO/WiMax on USB WiMax/WiFi on PCI-Express Also consider: The typical laptop with integrated wired and wireless LAN interfaces New Mobile Internet Devices (MID) and Ultra-Mobile PC (UMPC) From less than 6 million units in 2006, combo handsets will reach nearly 190 million by 2011. In-Stat research summary 21-09-0004-00-mrpm

Battery life for multiple interfaces without MPRM Active Standby Normal sleep Deep sleep Off Battery life (approx. numbers only for cellular ) 1 interface A 2 hrs 24 hrs 2 interfaces A,B 12 hrs 3 interfaces A,B,C 8 hrs 6  24 hours 3  24 hours 2  24 hours >> 6  24 hours 21-09-0004-00-mrpm

Existing Solutions End-User manually manages connections Manual configuration frustrates the end-user because: Time required to figure out which connection to use and enable it Frustrated by short battery life Knowledge required of the OS and installed interfaces to enable/disable interfaces Client-based (typically laptops) connection management software Searches for available networks Based on pre-programmed criteria the software chooses the “most desirable” network (not necessarily “best-available”) May or may not disable other interfaces (for the purpose of battery-life, network use cost-reduction, etc.) 21-09-0004-00-mrpm

Connectivity Response time Network, device, and application considerations in enhancing battery life Different modes of operation in different technologies Battery life also depends on Fast call set up PTT (interactive) + – Active/on Data rate? Play back-start Record-start Discharge rate? 802.16 Sleep? 802.11 Sleep? + – Connectivity Response time Temperature? 802.11 Idle? CDMA Sleep? Charge count? + – Webpage-start Streaming-start Background-start + – Off/deep sleep 21-09-0004-00-mrpm

MRPM mechanisms (using / extending MIH in network/device) Enhance battery life by providing a power management framework enabling control of multi-radio power states depending on characteristics of each radio’s power consumption and application needs: Enable a Network Selection Entity (NSE) to consider multi-radio power management policy inputs. Inform the NSE of the current radio power configurations of a mobile device: whether radio is on, off-available, or off-do-not-disturb, etc. to determine the optimal power configuration of a multi-radio mobile device. Signaling over an energy efficient channel while putting other radios in low power state. Detect traffic destined for a radio interface in the off-available configuration and notifying the mobile device through an alternative “on” radio interface. Avoid futile scanning using location and network information PoA location and coverage information. 21-09-0004-00-mrpm

Summary Multi-mode terminals are becoming popular Multi-mode terminals consume more power Each interface power is managed independently of the other radios Connection managers being used in terminals They are proprietary They don’t make use of any network signaling Integrated radio management is needed The most power savings can be obtained by powering off not needed radios Possibly keep one active and power off others 21-09-0004-00-mrpm

Backup slides 21-09-0004-00-mrpm

Define problem Multi-mode terminals are becoming popular Multi-mode terminals consume more power Each interface power is managed independently of the other radios Connection managers being used in terminals They are proprietary They don’t make use of any network signaling Integrated radio management is needed The most power savings can be obtained by powering off not needed radios Possibly keep one active and power off others 21-09-0004-00-mrpm

What MRPM Can Do to Help? Powering off interfaces Develop power saving enablers that operators can use Amend 802.21 to support power management of the multi-radio mobile node interfaces. Define media-independent primitives and signaling for power management. The signaling will be exchanged in the network among multiple radio networks including IEEE 802 Establish synergy between 802.21 and MRPM 21-09-0004-00-mrpm

Powering Off Interfaces Maximum power savings are obtained by powering off interfaces because in all other states interfaces consume power A powered off interface can be activated again by certain means such as signaling on the system bus Powering off interfaces is not a new idea, it’s been around since ten years or so MRPM has to proxy the powered off interface In cellular interfaces powered off interface should appear as “idle” MRPM has to proxy idle mode operations Such as idle mode entry and location update signaling 21-09-0004-00-mrpm

Multi-Radio Power Management The purpose of MRPM is to manage multiple MN radios in a way that increases MN operating time. This goal is complementary to, but distinct from, other operating and handoff criteria MRPM provides a mechanism for controlling the operating mode of a wireless network interface. MRPM provides a set of power management abstractions that allow tailoring each wireless technology’s operating modes to match network availability and the communication requirements of the MN user. 21-09-0004-00-mrpm

Multi-Radio Power Management MRPM is an information source, providing link energy efficiency input to network selection decisions. The MRPM inputs may be augmented by location services to facilitate radio scheduling by the MIH Network Selection Entity (NSE), the architectural component responsible for handoff policy enforcement. 21-09-0004-00-mrpm

Scenarios Extending 802.21 CS/ES Abstract Radio Power Modes Energy Consumption Metrics Utilizing Location Services Network Radio Proxy scenarios 21-09-0004-00-mrpm

Scenario-Turning off Radios for Undetected Networks Get out of the airplane Power on all interfaces Connect to the first discovered network Download neighborhood network info from MIH IS Turn off all other radios because the detected network turned to be the only one available Save power by using MIH IS 21-09-0004-00-mrpm

Scenarios- Energy Efficient Inputs for Network Selection Dual radio MN MN is currently connected to a network 2nd radio is in low power scanning mode. When 2nd radio network is discovered which is with a different technology, hand off to it to extend battery life determine that handing off to 2nd network will save power while satisfying current network demand. For two networks with the same technology then parameters of both networks are consulted to find that throughput is higher on 2nd network so energy cost will be less MN will handoff to the lowest cost for bit network MN will power off all other radios 21-09-0004-00-mrpm

Energy Consumption Metrics‏ technical detail IS metrics for network and link power consumption will be proposed 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. bit energy cost = mW * J/Ws * us/b = W*10-3 * J/Ws * s/b*10-6 = J/b*10-9 = nJ/b 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 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 21-09-0004-00-mrpm

Scenario: Sparse coverage problem Save battery life by not scanning for networks that don’t exist. MN is in a rural area with not many networks. MN is connected to some network queries MIH IS for a list of all networks in a relatively large geographic area. MN knows that when it leaves current coverage area that it won’t find another network for a long time. MN can determine its own location and uses coverage map obtained by MRPM enhanced MIH IS to know when it is approaching a new network coverage area. At that time it turns radio on and puts it in a low power scanning state. When radio detects the network it is set to the active state and connects to the network. 21-09-0004-00-mrpm

Utilizing Location Services Use nested circular coverage models to extend the 802.21 IE_POA_LOCATION element with TX_RANGE information. MN must be able to tell its location relative to, and independently of, any network POA GPS, gyros, ... May be augmented by network beacons, buoys, .... Coverage map from MIH IS and MN location combine to avoid scanning in out of coverage areas and to facilitate radio scheduling and advanced proxy services. TX_RANGE SEQUENCE( UNSIGNED_INT(2), UNSIGNED_INT(2) ) A type that contains two numbers. The first unsigned integer is the distance, R2, from a PoA where complete network coverage is available. The second unsigned integer is the maximum distance R1 to which network coverage may extend. Both values are in meters 21-09-0004-00-mrpm

Scenario: Emulate presence of a radio Dual-mode MN Radio A is connected to the current network A MN wants to receive calls coming towards its radio B on network B MRPM has to emulate MN’s presence in network B MRPM needs to have the presence emulated using “Network Radio Proxy” 21-09-0004-00-mrpm

MRPM Architecture MN NSE 21-09-0004-00-mrpm Current Network MRPM NRP Candidate PoA & NRPA Current Enabled MIH IS Current Network Proxied Network Multi-Radio Power Management Service Flow 21-09-0004-00-mrpm

Network Radio Proxy An MRPM Network Radio Proxy (NRP) is a new entity that MRPM will define. An NRP must be accessible to an MN over the MIH protocol via a current network PoA. The NRP makes it appear that a powered down radio on the MN has actually joined the candidate network. An NRP thus maximizes the candidate network availability while minimizing MN battery drain. The emulation of certain functions (e.g., MN location updates) are technology specific operations and may require an NRP Agent (NRPA) to exist on the PoA of such networks. 21-09-0004-00-mrpm

Emulation Scenario: Location Update Using Active Interface MN is moving MN’s location is known in Network A at cell level MN’s location in Network B needs to known at the tracking area level This requires location updates MRPM NRP should enable this technology dependent signaling Signaling is done using Radio A 21-09-0004-00-mrpm

Emulation Scenario: Location Update Using Active Interface While a proxy session is active, the MN may move from the coverage area of one PoA to another on the same network. When such a situation is identified, the NSE sends a PROXY_UPDATE to the NRP. The NRP would then change the NRPA that represents the MN on the network. Should mobility cause the MN to switch to a third network then the NSE will send a PROXY_MOVE message to the NRP, notifying it of the network change. Should the MN leave the coverage area of the proxy network then it will send a PROXY_LEAVE message to the NRP. 21-09-0004-00-mrpm

Network Radio Proxy Details NRP Service descriptions will need to be added to the MIH _NET_CAPABILITIES. The MIH NSE communicates with the NRP using the following message types: PROXY_REPLACE, PROXY_JOIN, PROXY_LEAVE, PROXY_UPDATE, PROXY_MOVE, PROXY_FILTER, PROXY_TRAFFIC_PENDING, PROXY_FORWARD and PROXY_WAKING_UP 21-09-0004-00-mrpm

Conclusions MRPM (Officially Multi-radio Power Conservation Management) will extend Base protocol 802.21 IS Base protocol CS & ES MRPM will not change air interfaces in 3GPP/2 or 802 technologies MRPM will propose new 802.21 entities, e.g. NRP MRPM will propose protocol between NRP and existing 802.21 entities, e.g. NSE More importantly MRPM will lead to power conservation for multi-radio terminals 21-09-0004-00-mrpm

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Multiple interfaces sharing a battery 802.16 3GPP; 3GPP2 Single-interface device: Different technologies have different modes of operation each with different power consumption 802.11 + – + – + – 802.16 3GPP; 3GPP2 802.11 Multiple-interface device: will drain battery fast if power consumption is optimized only within each individual network technology + – 21-09-0004-00-mrpm

Interface power consumption Interface modes Active or powered on Sleep or idle with paging channel on Powered off Interface power 70% of total power Multi-radio usage more mainstream Power breakdown for a connected multi-radio mobile device in idle mode Source: mobisys 2006 21-09-0004-00-mrpm

Power Management in Existing Technologies 21-09-0004-00-mrpm