LTE NB WUS (Wake Up Signal)
This tutorial is to show you how to configure and test LTE NB WUS (Wake Up Signal). Wake Up Signal is a kind of energy saving technology being used in LTE and NR. WUS is employed for Idle mode operation in LTE and is employed for connected mode in NR.
When it is used for Idle mode, WUS is used as a precursor for monitoring Paging Channel. When WUS is configured by eNB and the configuration is broadcasted by SIB, UE monitors WUS first without monitoring Paging. UE start monitor Paging only when it detects WUS. In this way, UE can save energy for waking up and monitors Paging signal by removing the unnecessary wake up.
Table of Contents
- LTE NB WUS (Wake Up Signal)
Test Setup
Test setup for this tutorial is as shown below.
Key Configuration Parameters
Followings are important configuration parameters for this tutorial. You may click on the items for the descriptions from Amarisoft documents.
- eNB config
- wus_config : In this link, you can find the descriptions for all the parameters below.
- time_offset
- max_num_rep
- num_po
- num_drx_cycles_relaxed
- UESim Config
Test 1 : WUS with Single Cell
Configuration
The configuration shown here is common configuration for all the subtests belonging to Test 1 and I will not show this configuration repeatedly for every subtest.
I have used enb-nbiot-wus.cfg which is copied and modified from enb-nbiot.cfg on Callbox (gNB)
I am using mme-ims.cfg and ue_db-ims.cfg as they are.
On UEsim, I used ue-nbiot-wus.cfg which has been copied and modified from ue-nbiot.cfg (
enb-nbiot-wus.cfg is configured as follows.
sib2_nb_wus2.asn is configured as follows.
ue-nbiot-wus.cfg is configured as shown below. (
Perform the Test
Run lte service on callbox and check 'cell' command.
This is not the mandatory process.. but I did this to collect SIB message in the log for a few seconds at the beginning. I did bcch=1 and after a few seconds did bcch=0.
Now start trace logging.
Power on UE on UEsim (If your DUT is a commercial phone, turn on the phone)
Wait until the DUT complete the initial attach.
If you don't see any furrther 't' output is getting printed, it is highly likely that UE got into idle mode. Now it is good time to send WUS (Wake Up Signal) and Paging message.
Before you try ping, double check UE IP as shown below.
Do ping from callbox to UE as shown below.
Log Analysis
Following is the log snapshot that are involved in WUS (Wake Up Signal)
RRC / NAS Signaling
SIB2 (LTE)
: This is SIB2 containing ephemeris
{
message c1: systemInformation-r13: {
criticalExtensions systemInformation-r13: {
sib-TypeAndInfo-r13 {
sib2-r13: {
radioResourceConfigCommon-r13 {
rach-ConfigCommon-r13 {
preambleTransMax-CE-r13 n10,
powerRampingParameters-r13 {
powerRampingStep dB2,
preambleInitialReceivedTargetPower dBm-110
},
rach-InfoList-r13 {
{
ra-ResponseWindowSize-r13 pp5,
mac-ContentionResolutionTimer-r13 pp32
}
}
},
bcch-Config-r13 {
modificationPeriodCoeff-r13 n64
},
pcch-Config-r13 {
defaultPagingCycle-r13 rf256,
nB-r13 oneT,
npdcch-NumRepetitionPaging-r13 r2048
},
nprach-Config-r13 {
nprach-CP-Length-r13 us66dot7,
nprach-ParametersList-r13 {
{
nprach-Periodicity-r13 ms320,
nprach-StartTime-r13 ms8,
nprach-SubcarrierOffset-r13 n2,
nprach-NumSubcarriers-r13 n36,
nprach-SubcarrierMSG3-RangeStart-r13 twoThird,
maxNumPreambleAttemptCE-r13 n5,
numRepetitionsPerPreambleAttempt-r13 n1,
npdcch-NumRepetitions-RA-r13 r8,
npdcch-StartSF-CSS-RA-r13 v2,
npdcch-Offset-RA-r13 oneEighth
}
}
},
npdsch-ConfigCommon-r13 {
nrs-Power-r13 -29
},
npusch-ConfigCommon-r13 {
ack-NACK-NumRepetitions-Msg4-r13 {
r1
},
srs-SubframeConfig-r13 sc2,
dmrs-Config-r13 {
threeTone-CyclicShift-r13 0,
sixTone-CyclicShift-r13 0
},
ul-ReferenceSignalsNPUSCH-r13 {
groupHoppingEnabled-r13 FALSE,
groupAssignmentNPUSCH-r13 0
}
},
uplinkPowerControlCommon-r13 {
p0-NominalNPUSCH-r13 -117,
alpha-r13 al1,
deltaPreambleMsg3-r13 0
},
wus-Config-r15 {
maxDurationFactor-r15 oneHalf,
numPOs-r15 n4,
numDRX-CyclesRelaxed-r15 n1,
timeOffsetDRX-r15 ms80,
timeOffset-eDRX-Short-r15 ms80
}
},
ue-TimersAndConstants-r13 {
t300-r13 ms2500,
t301-r13 ms2500,
t310-r13 ms200,
n310-r13 n6,
t311-r13 ms10000,
n311-r13 n5
},
freqInfo-r13 {
ul-CarrierFreq-r13 {
carrierFreq-r13 21359,
carrierFreqOffset-r13 v0
},
additionalSpectrumEmission-r13 1
},
timeAlignmentTimerCommon-r13 sf1920
}
}
}
}
}