9-HRPD-A LTE Handoff-A Mobile Perspective

8/6/2019 9-HRPD-A LTE Handoff-A Mobile Perspective

http://slidepdf.com/reader/full/9-hrpd-a-lte-handoff-a-mobile-perspective 1/10

LTE/CDMA Handoffs – A Mobile’s Perspective

Hosting Two Complete Networks in One UE….



2Motorola Confidential Proprietary.

MOTOROLA and the Stylized M Logo are registered in the US Patent & Trademark Office. All otherproduct or service names are the property of their respective owners. © Motorola, Inc. 2008.

Background

As systems evolve from 3G to 4G, more complicated mixesof technology are being chosen.

– Traditionally, evolutionary paths were within a common standardsorganization (3GPP or 3GPP2)

– The new world crosses technology boundaries:

• 3GPP2 HRPD-A (DOrA) <-> IEEE 802.16/WiMAX

• 3GPP2 HRPD-A (DOrA) <-> 3GPP Long Term Evolution (LTE)

– This requires an unprecedented amount of coordination betweenstandards organizations to support these systems.

The business case exists to support this, so the technicalwork is being done to support these soon to be deployed

systems. – Demonstrations are now being developed.





CommercialHRPD-AProvider

CTIA Handoff Demonstration (LTE/DOrA)

USB

CDMA EVDO rev A

Phone with Mobile IP

Client

Internet

Linux ‘ApplicationProcessor’ with

Mobile IP Client

RTSP

Server

Linux

‘Router’with Mobile

IP HomeAgent

Iterated Mobile IP

enables intersystemmobility without

having to modify thelegacy EVDO

network.

At CTIA Wireless 2008, Motorola Demonstrated thePossibility of HRPD-A/LTE Inter-working using thissetup.





CTIA Handoff Demonstration (continued)

Traffic routed selectively through each air interface.

– No Layer 3 signalling.

– Traffic consolidation point was in the USB connected PCacting as the system data sink.

– Utilized the live DOrA network to demonstrate thatinterface’s capability.

– Video quality matched the relative bandwidths of the RFactive RF connection.





Unique Multi-Mode User Equipment (UE) Issues

For multi-mode devices, such as a UE operating in bothDOrA and LTE, the UE has to be the following:

– A fully capable DOrA device.

• Multiple frequency bands.

• Receive Diversity.

– A fully capable LTE device.

• Multiple frequency bands.

• MIMO.

– A DOrA/LTE inter-working function.





Design Challenges

Operating Frequencies:

– Operating transceivers in all carrier-specified bands.

• LTE w/MIMO (800, 900, 1700, 1900, 2100, etc.)

• DOrA w/Diversity (800, 1900, AWS, 700, etc.)• Bluetooth/WiFi (2400)

• GPS (1575.42)

System Selection: – UE must scan both systems for acquisition.

• Carrier preference rules must be created and supported.

• UE must acquire system and get service in similar time to a

single-mode device.





Design Challenges (continued)

Overhead Information Acquisition:

– Single receiver UEs must use Alternate Network Broadcast ofOverhead Information

– Dual-active receiver UEs monitor real common channel

transmissions.

Session Setup:

– Utilize native setup procedures.• LTE will be more than adequate.

• DOrA can take more than 6 seconds for session setup(inadequate).

– Standards are being developed in 3GPP/3GPP2 to support tunneledsession pre-establishment.

• When operating in LTE, the DOrA session can be created

through this tunnel and made dormant.• Procedures support both dual and single receiver UE designs.• Eliminates excessive delay in session transfer.





Design Challenges (continued)

Bearer Support:

– Vocoders

• LTE will support 3GPP codecs

• DOrA will support 3GPP2 codecs.





Handoff Process

Process is simple:

– Monitor air interface for better connection possibilities.

– Report better candidates to network.

– Network queries available resources then commands handoff.

With a multi-mode terminal, this simple process is complicated by basicissues.

– In a dual active receiver design, the multi-mode UE can report allinformation autonomously.

– In a single receiver design, the system compensates for the UE’sinability to scan information from DOrA while connected to LTE,

transmitting to the UE:• CDMA System Time.

• All overhead information.





Handoff Process (continued)

Tunneled Handoff Message happens in both designs.

– No Access Channel transmission happens, whichmeans that closed loop power control information must

be transmitted from the eNodeB to compensate.

– LTE session is maintained up to the moment when theUE tunes to the new DOrA channel.

Documents

9-HRPD-A LTE Handoff-A Mobile Perspective