Hybrid Mode

Last updated: October 13, 2010

This section is only applicable to the lab application.

NOTE

The terms of the access terminal (AT) and access network (AN) that are used in the IS-856 (1xEV-DO) system are equivalent to the terms of the mobile station (MS) and base station (BS) used in the IS-2000/IS-95 (CDMA) system.

Overview

In a wireless network that supports both the IS-2000/IS-95 (CDMA) and IS-856 (1xEV-DO) systems, a hybrid mode AT/MS is capable of:

acquiring both the IS-2000/IS-95 and IS-856 systems, and maintaining registration and overhead information on both types of system concurrently.
A hybrid mode AT/MS on power-up will first try to search and acquire an IS-2000/IS-95 system and then acquire a collocated IS-856 system. Once acquiring, the AT registers to the IS-2000/IS-95 system and opens a session with the IS-856 system. It will then periodically monitor the IS-2000 paging channel and IS-856 control channel.

Note that some hybrid mode AT/MSs are designed as primarily a CDMA device with 1xEV-DO capabilities. This kind of hybrid mode AT/MS will first try to search and acquire a CDMA system before searching for a collocated 1xEV-DO system. If CDMA service is not acquired first, the hybrid mode AT/MS will not try to acquire 1xEV-DO service, even if available.
supporting services on both the IS-2000/IS-95 and IS-856 systems.
While operating on both the IS-2000/IS-95 and IS-856 systems, a hybrid mode AT/MS can connect services available on either system in response to an origination request or page match. The most advantage of hybrid mode AT/MS is able to monitor voice calls when in a 1xEV-DO data connection. Moreover, voice services takes a higher priority over packet data service. That is, the packet data being transferred will be pending and the voice call is serviced whenever there is a voice call.

The hybrid mode AT/MS supports two operating modes: non-simultaneous voice and data (non-SVD) mode and SVD mode. The key difference between the non-SVD and the SVD modes is as follows:
- For the AT/MS that supports non-SVD mode, whenever a voice call is received or originated on the IS-2000/IS-95 system while the AT having an active packet data transfer on the IS-856 system, the packet data being transferred will be pending on the IS-856 system. The packet data transfer will not resume on the IS-856 system until the voice call is terminated. To avoid wasting forward link capacity of the IS-856 system, the hybrid mode AT/MS sets the cover of the R-DRC channel to the null value shortly before tuning away to the IS-2000/IS-95 system (this stops forward packet transmission and causes the IS-856 data session to go dormant). When the voice call is terminated, the hybrid mode AT/MS returns to the IS-856 system and resumes the data session (coming out of dormancy).
- For the AT/MS that supports SVD mode, when there is a dormant/active data connection on IS-856 system and a voice call is attempted, the AT/MS will establish the voice call on IS-2000 system and also transfer the packet data session from IS-856 system to IS-2000 system via dormancy. If the user application attempts to send data, it will trigger a service option 33 packet data connection while keeping the voice connection on the IS-2000 system.
  
  NOTE
  The test set does not support SVD operation.
supporting handoff of an existing packet data session between IS-2000 and IS-856 systems.
NOTE
The data session handoff are not supported by a hybrid mode AT/MS when operating on an IS-95 system.

Since packet data service can be provided on either an IS-2000 system or an IS-856 system, a hybrid mode AT/MS is able to handoff an existing packet data connection across systems when the current connected system is unavailable. However, the preference of packet data service is given to the IS-856 system when both systems are available.
- A hybrid mode AT/MS can handoff an active or dormant data connection from IS-856 system to IS-2000 system.
  This is because the AT periodically monitors the IS-2000 channel and has knowledge of both the IS-856 and IS-2000 channel conditions and the up-to-date IS-2000 overhead information. When IS-856 system is lost (for example, user drives out of the IS-856 system coverage) during an active or dormant data connection, the hybrid mode AT/MS will initiate an SO33 packet data connection on the IS-2000 system.
- A hybrid mode AT/MS can handoff a dormant data session from IS-2000 system to IS-856 system, but does not support an active data session handoff from IS-2000 system to IS-856 system.
  When a packet data session is dormant on IS-2000 system, AT monitors for IS-856 system. Since the preference of packet data service is given to the IS-856 system, AT immediately hands off the dormant data session from IS-2000 system to IS-856 system when IS-856 system is available and found.
  
  The hybrid mode AT/MS does not support monitoring IS-856 system when IS-2000 traffic channel is active. Therefore, when the AT has an active packet data session on IS-2000 system, it stays on IS-2000 system (even if the IS-856 system is available) until data connection is terminated on IS-2000 system.
- A hybrid mode AT/MS supports implicit handoff during origination. If AT fails to open IS-856 data connection for a few attempts, AT transfers the data session and originates on the IS-2000 system.

How Does Test Set Support Hybrid Mode AT/MS Tests?

Prerequisite Setup

To perform the functional test of the hybrid mode AT/MS, two test sets, one providing a CDMA network emulation and another one providing an 1xEV-DO network emulation, are required. A typical connection diagram for hybrid mode AT/MS test is shown in the figure below and followed with description.

Make sure you have two test sets available. The test set #1 running the E6702B lab application is to emulate an IS-2000/IS-95 system (CDMA) and the test set #2 running the E6706A lab application is to emulate an IS-856 system (1xEV-DO).
Have the two test sets synchronized on CDMA system time. For detailed procedure on how to get the two test sets synchronized, see Multi-unit Synchronization . Once the two test sets are synchronized, the trigger connection between the two test sets are not necessary but the 10 MHz REF connection should be kept.
Connect the two test sets' individual RF In/Out ports together to a lowloss resistive combiner and the output of the combiner is connected to the antenna port of the hybrid mode AT/MS.
If you want to log the messages exchanged between the hybrid mode AT/MS and test sets, a PC running the wireless protocol advisor (WPA) software is required to be connected to the same subnet of the two test sets. In addition, the PC can be installed as a WAP, FTP, HTTP server (depending upon your packet data application) for verifying your hybrid AT/MS packet data capabilities.

The following additional setups are required for hybrid mode AT/MS tests using mobile IP (MIP) (see tests 21-28 on Specific Procedures for Recommended Tests ).

An external mobile IP simulator (MOB-IP-SIM, provided by the Software Concepts, Inc.) is recommended to connect to the same subnet with the two test sets. The MOB-IP-SIM provides functions such as PDSN simulation, Home Agent, etc. to allow testing the hybrid mode AT/MS that uses mobile IP technology to provide seamless high speed data connections in a mobile environment. For details on the MOB-IP-SIM functionality and configurations, see the MOB-IP-SIM technical manual available on the web:
http://www.softwareconceptsinc.net/MIP-5850.html

Now, the hardware connection is finished and you are ready to perform the hybrid mode AT/MS tests.

General Test Procedure

There are many test cases recommended by Qualcomm® to evaluate the hybrid mode AT/MS's capabilities (as described on Overview ). For details on these tests' definitions, see Recommended Functional Tests for Hybrid Mode AT/MS .

The general procedure for the hybrid mode AT/MS test is as follows:

Make sure you have finished the Prerequisite Setup , especially ensure that the two test sets are synchronized on CDMA system time.
Set the call parameters on the two test sets properly so that the hybrid mode AT/MS can successfully acquire both the IS-2000/IS-95 and IS-856 systems, get registered on the IS-2000/IS-95 system and open a session on the IS-856 system.

NOTE
Most ATs will immediately initiate a session with the IS-856 system (1xEV-DO) once they reach the idle state upon power-up. So you will see Session Open state is always shown on the test set #2 when the hybrid mode AT/MS has successfully acquired/negotiated on the IS-856 system (1xEV-DO).
Change the parameters as required for each recommended test and verify the hybrid mode AT/MS's behavior.

For the detailed test procedure, see How Do I Make Hybrid Mode AT/MS Tests? .

Operating Considerations

Prior to making the hybrid mode AT/MS tests, make sure your AT/MS is correctly programmed to operate in the hybrid mode. Refer to your wireless device's technical manual for details on the configuration.
Prior to making the hybrid mode AT/MS tests, make sure you have made the proper connection and the two test sets are synchronized on CDMA system time. See Prerequisite Setup .
The two test sets should not operate on the same RF frequency. The RF frequency for each test set is determined by the Cell Band and Channel settings. You should set the test sets to match the parameters stored in the hybrid mode AT/MS.
The Preferred Control Channel Cycle Control must be set to AT Specified (fromCall Control 2 of 3 , F2 Access Network Info , F1 Configurable Attribute Ctrl ). This allows the AT/MS to propose the PCCC attribute during the session negotiation to guarantee that the preferred 1xEV-DO control channel cycle offset does not overlap in time with the CDMA paging channel slot that the AT is required to use.
To ensure that the hybrid mode AT/MS can successfully acquire the systems, you may need to set the SID on the test set #1 (CDMA) and/or the Sector ID on the test set #2 (1xEV-DO) to match the parameters stored in the hybrid mode AT/MS.
To establish a packet data connection on IS-856 system, Default Packet Application must be firstly set on the test set #2 (1xEV-DO). For details on packet data applications on IS-856 system, see Data Channel .
To establish a packet data connection on IS-2000 system, service option 33 (SO33 or SO33 (+F-SCH) ) must be firstly set on the test set #1 (CDMA). For details on packet data applications on IS-2000 system, see:
cdma2000: Data Channel
The test set does not support simultaneous voice and data (SVD) operation. For details on the SVD and non-SVD operating modes, see Overview .