1. 1 IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: 21-06-0701-00-0000-Media-Independent_IdleMode-and- paging Title: Media Independent Idle Mode and Paging Date Submitted: May, 2006 Presented at IEEE 802.21 session #15 San Diego Authors or Source(s): Muthiah Venkatachalam Abstract: This presentation talks about the concept of paging in multi-radio environment.

2. 2 IEEE 802.21 presentation release statements This 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 and in Understanding Patent Issues During IEEE Standards Development http://standards.ieee.org/board/pat/guide.html> Section 6.3 of the IEEE-SA Standards Board Operations Manualhttp://standards.ieee.org/guides/opman/sect6.html#6.3 http://standards.ieee.org/board/pat/guide.html

3. 3 Multi-Radio Networking Evolution Multiple Wireless Technologies More Capable Devices Evolving Usage Models Multi-radio operation is becoming the Norm…

4. 4 Overview So far the focus of 802.21 has been primarily handovers. –Vertical handover is something that needs to be addressed in the context of multi radio networking. Multi radio operation does not stop with handovers! –Host of other issues for multi radio operations exist. –Many of these could be better solved by means of standardized primitives. We talk about another key multi radio networking issue –How best to extend the battery life of a multi radio MS

5. 5 Extending battery life.. Most radio technologies define low power modes for power saving and extending the battery life. –Commonly called “idle mode” When the MS does not have any traffic on a radio interface for a period of time, the interface may switch to “idle mode” from “connected mode” –Switch may happen from the MS or from the network. Once in idle mode, –the radio of the MS is typically tracked at a granularity of a “paging group” or a “tracking area”, comprising of multiple BS/APs. –the radio has to listen to Downlink transmissions for a certain amount of time periodically, so that the network may be able to contact the MS In a multi radio environment, the MS may have multiple radios –Each radio may be in “connected” or “idle” states

6. 6 Key operations during idle mode Location Update –When the radio of the MS crosses a paging group, it performs location update –Location Updates keep the network updated on the location of the MS Paging –When there is incoming packets for the MS on its idle radio interface, the network may choose to “page” the MS. –Paging is typically initiated by a paging controller that has the latest location of the MS. –Paging would involve contacting multiple BS/APs in the paging group to locate the BS/AP where the MS is currently present. Idle mode exit: switch back to connected mode, happens when –When the MS wants to transmit data on the uplink on the given radio, –or when the MS is paged and wants to get back to connected mode.

7. 7 Power saving at the MS If the MS is guaranteed that it will be paged on one (or a subset) of the radios all the time, then –It can periodically listen to the downlink transmissions only on this radio. –It can switch off the other radios. May lead to considerable power saving at the MS For example: MS has WiMAX and 3G interfaces, and –the MS knows that it will always be paged on WiMAX –The MS would not need to listen to the 3G downlink transmissions periodically.

8. 8 Paging-elimination Scenario –User is browsing on the WiFi interface –User gets a voip call on the WiMAX interface. –WiMAX network needs to page the user Instead of paging the user on the WiMAX airlink and spending considerable resources, the WiMAX network: –Determines if any other radio is currently on for the user –Eliminates paging by sending a unicast message on WiFi to turn on the WiMAX radio. Need standard compliant message primitives to do so.

9. 9 Paging-aggregation Page on a single idle radio to wake up multiple idle radios. Need standard compliant message primitives to do so.

10. 10 Location Update via “connected” radio User has WiFi connection that is currently active and WiMAX connection that is idle. WiMAX radio needs to do a location update –Instead of contending on the WiMAX airlink, it uses the WiFi radio to perform location update for its WiMAX radio Need standard compliant message primitives to do so.

11. 11 Aggregated Location Update If the PGs are overlapping, perform a single LU operation for multiple radios. Minimizes messaging and processing at the MS Need standard compliant message primitives to do so.

12. 12 Idle mode entry Scenario: Multiple radios are switched to idle mode –For example: when the user takes a break, his WiMAX, WiFi and 3G connections may go into idle mode IM Entry for radios i, j, k happens on radio-i. Need standard inter-radio message primitives to do so.

13. 13 Summary Standards based multi radio primitives for idle mode will help –Save power at the MS –Reduce signaling, processing and contentions –Improve performance for the user and cost savings for the operator 802.21 can take a first step here to move the industry toward an integrated framework for low power mode of multi-radio operation –By studying the issues more closely –By defining the primitives for such a framework Vertical radio standard bodies can then use these primitives to optimize the low power operation in the multi radio scenario.