eHRPD-LTE Inter Technology Spectrum Optimization Source: Qualcomm Incorporated Contact: Jun Wang/George Cherian September 9, 2013 Notice ©2013. All rights reserved. Qualcomm Incorporated grants a free, irrevocable license to 3GPP2 and its Organizational Partners to incorporate text or other copyrightable material contained in the contribution and any modifications thereof in the creation of 3GPP2 publications; to copyright and sell in Organizational Partner’s name any Organizational Partner’s standards publication even though it may include all or portions of this contribution; and at the Organizational Partner’s sole discretion to permit others to reproduce in whole or in part such contribution or the resulting Organizational Partner’s standards publication. Qualcomm Incorporated is also willing to grant licenses under such contributor copyrights to third parties on reasonable, non-discriminatory terms and conditions for purpose of practicing an Organizational Partner’s standard which incorporates this contribution. This document has been prepared by the Qualcomm Incorporated to assist the development of specifications by 3GPP2. It is proposed to the Committee as a basis for discussion and is not to be construed as a binding proposal on Qualcomm Incorporated. Qualcomm Incorporated specifically reserve the right to amend or modify the material contained herein and nothing herein shall be construed as conferring or offering licenses or rights with respect to any intellectual property of the Qualcomm Incorporated other than provided in the copyright statement above.

Problem Description Background In the current eHRPD/LTE interworking architecture, all the IP flows are carried either on LTE or on eHRPD Solutions proposed in this contribution Enable active IP connections on eHRPD & LTE simultaneously Two mechanisms are considered: Same IP address assigned both on LTE & eHRPD Different IP addresses are assigned on LTE & eHRPD Mechanism for defining & enforcing IP flow distribution based on feedback from RAN loading Radio Layer Issues: The UE will need to be able to connect both eHRPD and LTE at radio layer Not addressed in this contribution

Enable active IP connections on eHRPD & LTE New procedure/signaling marked in RED

Simultaneous active IP connections on eHRPD & LTE The following changes are needed on eHRPD Network: Authorization of the UE for simultaneous IP connection UE sends IP address assignment request message (VSNCP Config Request message) with a new indicator called, “simultaneous IP” PMIP Binding Update indicating “simultaneous IP” The following changes are needed on LTE Network: Authorization of the UE for simultaneous IP connection PDN Connection establishment to indicate ‘simultaneous IP connection’

IP flow distribution based on feedback from RAN loading Two methods are considered UE based Network based Both methods consists of the following steps Policy definition based on load Preferred RAT for the QCI/flow Maximum allowed load on preferred RAT beyond which flow is transferred to less- preferred RAT Load information may be applied on a per-class basis Transfer of the policy to P-GW & UE Actual mechanism of transfer depends on the approach choses (see later slides) Application of the policy both by P-GW & UE Based on the policy, the packets belonging to the QCI/flow is transferred on the chosen RAT If same IP address is assigned to the UE both on LTE & eHRPD, then: P-GW maps the 5-tuple to the RAT. Further packet filtering (5-tuple to radio bearer mapping) performed after RAT selection If different IP addresses are assigned to the UE between LTE & eHRPD, then existing packet filtering rules can be reused Enforcement of the policy by P-GW

UE based approach 1.New parameters is added to ANDSF Load information per QCI (or per flow): Maximum allowed load on LTE beyond which flow is transferred to eHRPD Load information may be applied on a per-class basis 2.RAN (eNB & eAN) broadcasts the load information of the network to the UEs Load information may be indicated as different levels, which is consistent with the UE ANDSF data base 3.Load information from RAN (eNB & eAN) is forwarded to P-GW Used by P-GW for enforcement. Otherwise, this step is not needed 4.UEs applies the ANDSF rules based on load information obtained from the RAN UE transfers the flow onto the chosen RAT based on the policy P-GW updates the routing based on the flow initiated by the UE from uplink packets, and applies the policy on the downlink direction If the P-GW obtained the rules (at step-3 on slide 3), then the P-GW applies the policy for downlink packets based on that.

Network based filtering & distribution of packets between LTE & eHRPD 1.PCRF sends the policy to P-GW using a new parameter Load information per QCI (or per flow): Maximum allowed load on LTE beyond which flow is transferred to eHRPD 2.Load information from RAN (eNB & eAN) forwarded to P-GW 3.P-GW modifies the flow distribution rules, signals it to the UE On eHRPD: P-GW sends the information to HSGW using PMIP signaling HSGW sends the policy to UE using RSVP signaling 5-tuple to RAT mapping is added (in addition to 5-tuple to Radio link ID mapping) On LTE: Option 1: P-GW sends the information to MME though S-GW (using GTP signaling) MME sends the policy to UE using MME-UE signaling (e.g., NAS signaling Option 2: P-GW sends the information to UE through P-GW-UE signaling (e.g., PDN connection modification, PCO etc) 4.P-GW enforces the policy

Decision of Using Same or Different IP address The following entity can decide if same or different IP address should be used: o P-GW per operator policy o PCRF indicates to P-GW through policy interface o HSS/AAA indicates to P-GW through authentication procedures o Normally whether to use same or different IP address should apply to all UEs Same IP addressDifferent IP address ProsTransparent to Application, no service interruption. Simple to P-GW implementation since there is no need to add RAT selection in packet filtering rule ConsP-GW needs to change packet filtering rule Some application may not be able to handle service continuity if the flow is moved between RATs