Slot Cycle Index Setting Notes

Slot Cycle Index Setting NotesSecurity Level:

Case TitleSlot Cycle Index Setting NotesAbstractEvery network parameter modification is related to the network quality & resource. If the changes are made to improve the network quality, there will be a resource trade off. This document address the Slot Cycle Index (SCI) setting for CDMA 1X network with EVDO network overlay. The setting value would impact the devices battery standby time and paging success ratio, based on the operators preference.

Keywords CDMA, EVDO, Slot Cycle Index (SCI), Network OptimizationCase Text:1. Introduction

Every network parameter modification is related to the network quality & resource. If the changes are made to improve the network quality, there will be a resource trade off. Vice versa, to utilize the network resource, the network quality would be sacrificed.

Therefore, in the standard network optimization process, the change recommendation will be determined by the network statistics and the real-time tests for the existing network. For the Greenfield network, the vendors default values will be set initially. The optimization will also be based on the test results and network statistic.2. Objective

The CDMA Paging Channel is the shared channel that all phones listen to for incoming calls and other control info. To conserve power, the idle phones only "wake up" and listen for messages on the Paging Channel during their assigned slots. The slot cycle index determines how often the phone's slot comes around. If the slot cycle index is 0, the phone wakes up every 1.28 seconds. If it's one, it wakes up every 2.56 seconds. If it's two, it's every 5.12 seconds, and so on. The larger the setting, the more power is conserved, but the longer it takes to page the phone for an incoming call. If the SCI were set to 10.24 seconds, few callers would hang on the line long enough for the phone to be answered. There are two settings that govern this. One is the "preferred slot cycle index" in the phone, and can be set via service programming. The other is the "maximum slot cycle index" set in the base station and broadcast in overhead messages on the Paging Channel. The phone has to use whichever number is smaller.

The typical 1x2000 network Slot Cycle Index setting is 0 or 1. Due to the EVDO network data throughput improvement purpose, there is consideration to set the SCI to 2 which may help the data performance.

However, since the EVDO slot cycle occurs every 5.12 seconds (defined in the protocol), the CDMA1x SCI2 (identical to EVDO slot cycle) has a higher probability of conflict between 1X paging and EVDO paging, that requests AT goes to negotiate with system to change the paging slot assigned to it. Please refer to the appendix 5.1 for the detail.

3. Procedure

There are several network parameters (appendix 5.2) that should be modified corresponding to the CDMA1x SCI change. Since each single network has different morphologies, design, subscribers distribution, etc. All the settings will be determined from the current network switch statistics and real-time field testing.

3.1. Networks Data Gathering & Real-Time Field Testing

Collect the data as the benchmark before applying any change to the network. This includes two kinds of information:

OM statistics related with paging performance (NSS), call setup performance (BSS), DO data throughput (BSS) shall be collected.

Field test with signaling tracing from both NSS and BSS side to obtain statistics of paging and call setup.

3.2. SCI Change and Relative Parameters Change

Implement the modification according to the attached SCI changes MOP. After modification of the parameters, repeat step 3.1 to collect the information and monitor the network condition. If there is any network degradation, change back to the original values.

It is strongly recommended to modify each parameter gradually, testing and verifying after each modification, until the proper values been determined and set as the final setting.

The RF team shall be responsible for modification of SCI, BSC timer.

The NSS Team shall be responsible for modification of other related parameters in the Softswitch.3.3. Network Quality Verification

Once all the changes have been completed and the network quality has not been degraded, collect all the data and compare to the initial benchmark data. That includes:

IOT result of all types of mobiles using SCI2 in commercial network.

Field test with signaling tracing from both NSS and BSS side to obtain statistics of paging and call setup. OM statistics related with paging performance(NSS), call setup performance(BSS) of 1X mobile and EVDO AT, DO data throughput(BSS) of hybrid AT shall be collected. 4. SCI and Related Parameters

Query current parameters setting

1. SCI

LST SYSMSGPARA, and then select SPM, to get current SCI value.

2. Max times of paging to being repeated

LST PAGINGSTRA, to get current value.

3. Interval between paging resending

LST PAGEINTVL, to get current value.

Command of parameters modification

1. SCI

Command:

MOD SPM: MAXTSPRDIDX= (SCI setting value), BATCHMODSIGN = "FFFFFFFF";

2. Max times of paging to being repeated

If SCI is set to 1, 3 times to resend un-responded paging message is suggested. If SCI is set to 2, then 2 times to resend un-responded paging message is suggested.

Command:

MOD PAGINGSTRA

3. Interval between paging resending

The values for interval between paging resending should be determined upon the process results in the section 3.

Command:

MOD PAGEINTVL

5. Appendix

5.1. SCI Protocol and Qualcomm Recommendation

In CDMA1X/EVDO system, the hybrid AT is able to receive a Page message when it is on the 1xEV-DO system because the AT is in slot-mode operation with 1X/EVDO network. If the AT is a hybrid mobile, it is required to monitor the paging channel on the 1X system as well as the 1xEV-DO slotted control channel. The AT will wake up in its designated 1X slot to monitor the 1X paging channel. If the AT is on the 1xEV-DO traffic channel, the AT may send a null DRC to indicate that it does not want to receive any data from the network while it is monitoring the 1X paging channel. If there is no page message for the AT on the 1X system, the AT would come back to the 1xEV-DO system to resume its data connection by pointing a non-null DRC to some sector. If there is a page message for the AT, the AT would stay in the 1X system to continue call setup procedures.

A dual-mode 1xRTT/1xEV-DO mobile using slotted-mode paging can effectively watch the paging channels of both 1xRTT and 1xEV-DO. For EVDO, slot cycle occurs every 5.12 seconds defined in the protocol, see figure 1 for detail. For 1X, according to the value of Slot Cycle Index, it can be 0(1.28seconds), 1(2.56seconds), 2(5.12seconds) in protocol (SCI= 1.28 * 2^ i), see figure 2 for detail. SCI=1 is recommend for 1X from Qualcomm, and its verified in a practical network to be good for the call setup and paging performance.

Figure 1. EVDO Slot Cycle

Figure 2. 1x RTT Slot Cycle Index

The Inter-Operability between 1x and 1xEV Networks are covered in the TIA Standard, IS-856.

5.2. Analysis of Mobile Throughput Impact from Qualcomm

The average data throughput seen by a particular hybrid access terminal from the IS-856 access network is not expected to be noticeably impacted by the periodic interruptions required to monitor the IS-2000 paging slot.

The hybrid access terminal monitors the IS-2000 paging channel when active on an IS-856 access network, which does imply an impact to the peak data throughput achievable by a hybrid access terminal. When monitoring the IS-2000 paging channel, a hybrid access terminal must periodically tune away from the IS-856 access network. During the time the hybrid access terminal is monitoring the IS-2000 paging channel, the IS-856 access network cannot schedule packets to that particular hybrid access terminal. However, in a practical deployment, multiple access terminals will be receiving service on the forward link at a given time. Using a fairness-based scheduler, such as the one currently in use, an access terminal accumulates credit for the time away from the IS-856 access network, and receives the corresponding scheduling priority after returning to the IS-856 access network.

The fraction of time that a hybrid access terminal is unavailable for packet data service on an IS-856 access network depends on the slot cycle index of the IS-2000 access network being monitored and the time required monitoring the IS-2000 paging slot. The time required away from the IS-856 access network is determined by the time required to tune to the IS-2000 frequency, reacquire the IS-2000 access network, receive the IS-2000 paging channel information, tune back to the IS-856 frequency, and reacquire the IS-856 access network. Because the IS-2000 and IS-856 access networks are synchronized to the same timing reference, the time required to reacquire either type of access network after tuning to the corresponding frequency is greatly reduced relative to the time required to reacquire without the availability of system timing. The time required can be further reduced in a system where the IS-2000 and IS-856 sectors are co-located and use the same pilot PN offsets.

In the event that the IS-2000 paging channel is available and there is no need to access the IS-2000 system, the mean time the hybrid access terminal is required to be away from the IS-856 system to monitor the IS-2000 paging slot is expected to be approximately 100 msec, and the worst case time is expected to be no greater than 250 msec. Additionally, use of the IS-2000 Quick Paging Channel may improve these times. These times are dependent, in part, on the actual access terminal radio hardware, and may therefore vary between different access terminal designs.

Simulations have been performed to characterize the impact of IS-2000 slotted operation on access terminal data throughput on an IS-856 access network. Simulation parameters and results for the Pedestrian, 2 antenna cases are presented in Table 1 and Figure 3.

Table 1 Mobile throughput simulation parameters

Figure 3 shows that the impact on the application layer TCP throughput available to a hybrid access terminal operating on an IS-856 access network is negligible for typical durations of time spent away from the IS-856 access network to monitor the IS-2000 paging slot.

Figure 3 User throughputs vs. away time for Pedestrian A, 2 antennas5.3. Switch Parameters

Below is the definition of the parameter.

Parameter ID Parameter name Parameter description

PIT1 Paging interval T1 (Second) The interval between the first paging message and the second one in voice/data/location services.

PIT2 Paging interval T2 (Second) The interval between the second paging message and the third one in voice/data/location services.

PIT3 Paging interval T3 (Second) The interval between the third paging message and the fourth one in voice/data/location services.

RPI Remain paging interval (Second) The interval between two paging messages after the fourth paging message in voice/data/location services.

PISMT1 Paging interval of SMS T1 (Second) The interval between the first paging message and the second one in normal short message services, OTAPA services, or SDB services.

PISMT2 Paging interval of SMS T2 (Second) The interval between the second paging message and the third one in normal short message services, OTAPA services, or SDB services.

PISMT3 Paging interval of SMS T3 (Second) The interval between the third paging message and the fourth one in normal short message services, OTAPA services, or SDB services.

RPISM Remain paging interval of SMS (Second) The interval between two paging messages after the fourth paging message in normal short message services, OTAPA services, or SDB services.

AISMT1 ADDS paging interval T1 (Second) The interval between the first ADDS_PAGE message and the second one in the short message service.

AISMT2 ADDS paging interval T2 (Second) The interval between the second ADDS_PAGE message and the third one in the short message service.

AISMT3 ADDS paging interval T3 (Second) The interval between the third ADDS_PAGE message and the fourth one in the short message service.

RAISM Remain ADDS paging Interval(Second) The interval between two ADDS_PAGE messages after the fourth ADDS_PAGE message in the short message service.

Table 2 Switch Parameters List6. Case Study

Country A, operator C has current 1x2000 network Slot Cycle Index setting to 1. The market operational management plans to modify the SCI to 2 after the EVDO network turned on for data throughput improvement.Huawei provided the SCI modification guideline and suggestion, in the same time helped the customer analyzed some network data as well.Note:

1. Unknown for the EVDO data throughput improvement

2. In CDMA1x/EVDO system, the hybrid AT will listen to the CDMA1x network periodically (SCI setting). During the EVDO data download session, the frequent listen to the 1x network, the more interrupt to the DO data download.

3. The 1x network performance may be impacted

6.1. Pre-Analysis Networks Data & TestPage Duration distribution Analysis:

The paging duration measurement had been collected and analyzed to understand the majority of the page responses duration. The charts below indicated the 85% or above of paging duration are under 3000 ms, only around 10% of the paging duration laid in 4000 ms, and the remaining 5% are exceed the range.

Figure 4. Page Duration distribution

Figure 5. Page Duration Trend

Page Success Ratio:

The network page success ratio was also reviewed. The sample file below indicated the page success ratio is very between different times during the day. The range is 93% to 97% and the average success ratio is 96.4%.

Table 3 Page Success Ratio

Page Success Responses:

The sample analysis below indicates the percentage of page responses on the 1st page, 2nd page and 3rd page. Most of the page responses (success) occurred after the 1st page, only a few page responses occurred on the 2nd and 3rd page. It means the system has proper timer setting corresponding to the SCI 1.

Table 4 Page ResponsesIMSI/ESN Trace:

The device real-time traces to match the network level page duration. The average page duration is 2.02 seconds for this sample device below, which is satisfied to the current SCI setting in 1 (2.56 seconds). For the EVDO SCI setting to 2, the page duration may be measured for relate timer settings.

Table 5 IMSI Trace for Page DurationFTP Throughput Measurement:

This is the sample measurement point set to FTP server. Jagged 1-second throughput curve caused by SCI 0 value. Every second there is a transmission gap of up to 300 ms. This is affecting the bucketing of transferred data.

6.2. Method of Procedure for SCI Change

Huawei provided the SCI modification MOP for customer to follow step by step. The recommendations to customer modify each associate parameter gradually, testing and verifying after the change in place.

The following attachment is the MOP for the SCI change.

6.3. Post-Change Verification

The customer conducted the change and collected the related data and information to verify the result of change. The modification did not show significant improvement due to the different networks & subscribers scenario. The customer did not provide the data result, therefore, this case is closed.7. Conclusion

According to this customer SCI modification support excise, the following are the conclusions for the future reference.

Mobile station operating in slotted mode usually monitors 1 or 2 paging channel slots per sleep cycle

The translation parameter maximum Slot Cycle Index (SCI) defines this sleep cycle

Mobile uses the minimum value of the one programmed in its memory and the one it receives over-the-air from the network

Tradeoffs associated with Slot Cycle Index

Higher value of SCI increases mobile battery life. However, it may degrade the overall termination performance

As mobile sleeps more, there are fewer RF information updates (Idle handoffs)

Mobile will likely respond to the termination request on a weaker pilot

There is no firm recommendation on the value of Max. SCI. Service providers should understand the possible tradeoff while setting Max. SCI.

Hybrid mode AT periodically monitors 3G1x paging channel

Update 3G1x overhead messages for voice page

The Slot Cycle Index govern the frequency of the 3G1x Tune-away

A value of SCI=0 results in maximum 1xEV throughput degradation in a single user scenario (up to 20% loss in throughput with single, stationary user in good RF condition)

Single , stationary user requesting 2.4567 Mbps rate

The loss in 1xEV throughput above is a minimum bound. The loss will be higher during drive testing

3G1x handoffs and mobile hashing

The loss in 1xEV data throughput performance may vary with different handsets

Handsets based on 6500 chipset will experience smaller loss. The difference in SCI impact between MSM6500 and MSM5500 is due to the rate at which the reverse traffic channel resumes data transmission after 1x Tune-Away (from some research document for this conclusion)

8. Reference

Qualcomm 80-V2301-1[1][1].X3(cdma2000 Hybrid Access Terminal Operation White Paper) Huawei CBSS Product guideline

Huawei MSC & BSS paging parameter setting principle

Alcatel-Lucent 1xEV-DO Data Network Testing and Analysis Services Report

2012-05-18HUAWEI ConfidentialPage1, Total11

_1397288568.docHuawei Technologies Co., Ltd.

MOP for BTS (SCI) Slot Cycle Index Changes

Prepared by: Huawei Technologies Co., Ltd

Date: 20xx/11/08

Reviewed by: C Communications

Date:

Huawei Technologies Co., Ltd.

All rights reserved

1 Requirements

1) Cricket to have staff in the switch room.

2 Preparations:

1) Notify the NOC

3 Impact

There is may be service impact to the all calls. This will need to be executed during the Maintenance Window.

Paging response success ratio may decrease

Subscribers may compliant for not receiving the incoming call while locate in weak network coverage area

Huawei has no comment for this parameters modification activity, but provides the assistance by the customers request.

4 Issues

Customer wants to change the SCI slot index to 2.

5 Procedure for SCI change

The procedure to change the SCI slot index value will require the following steps:

1) Change the SPM values on the BSC

2) Change the Paging values on the Switch

5.1 Modifying the current SPM values on BSC

Modifying the current SPM values:MOD SPM: MAXTSPRDIDX=2, BATCHMODSIGN="FFFFFFFF";

SCI is the SCI value to changed to, customers recommendation is 2

5.2 Modifying the Paging values on Switch

The Paging Strategy for Current Switch is to page 3 times, the interval between the three pages are 7, 5, 5 seconds. Now for change the SCI value, the Paging Strategy has to be changed accordingly. According to customers recommendation, the Paging time needs to be changed to 2 times. The interval would become 10 and 7.

The following change based on customers recommendation.

1) Modify the current Paging Strategy Information.

MOD PAGINGSTRA: MPN=1,

2) Modify the current Paging Interval Information.

MOD PAGEINTVL: PIT1=10, PIT2=7, PISMT1=10, PISMT2=7;

6 Rollback

6.1 Rollback on BSC

MOD SPM: MAXTSPRDIDX=1, BATCHMODSIGN="FFFFFFFF";

6.2 Rollback on Switch

MOD PAGINGSTRA: MPN=2,

MOD PAGEINTVL: PIT1=7, PIT2=5, PISMT1=7, PISMT2=5;

7 Test and Verification

The RF team conducts the call test (record the CDR) and collects the O&M report (paging success ratio) prior to the setting change. The same test and data should be collected post-change for the result comparison. If necessary, the setting might be modified over & over until the proper value been defined in turns to achieve the network optimization purpose.

The attachment below is the result of call test CDR data (processed) for the post-change call test comparison.

_1397055155.xls

Sheet1

Message IDMessage typeMessage DirectionArrive timeTimersTimersDuration

30[A1] Paging RequestMSC->BSC12.18.39.953.75039.95339.953


76[A1] Paging ResponseBSC->MSC12.18.40.959.75040.95940.9591.006





























































































































































































































































































































































































































































































































































































































































































































































































































































































































































































37855[A1] Paging R

Slot Cycle Index Setting Notes

Documents

Transcript of Slot Cycle Index Setting Notes