Voice over Long Term Evolution, Voice over LTE or with abbreviated version VoLTE. Typically the mobile operators are using CSFallback feature for voice calls in new deployed LTE networks which is cheaper solution than VoLTE. Legacy networks such as UMTS, GSM or CDMA are used for CSFallback, so the UE needs to go back from LTE to one of the mentioned legacy networks then start a voice call. It may cause call setup delay, sometimes blocked calls or other undesired problem.

— VoLTE Overview
— SRVCC
— IMS Overview
— VoLTE Speech Codecs
— Speech States

If an IMS network is deployed with LTE, then no need to use CSFallback (if all UE support VoLTE in the network). It is expensive solution to support voice calls in LTE but better solution.

No setup delay because of CSFallback, no inter-system transition issues because of legacy networks and HD Voice service can be used with EVS codecs (Enhanced Voice Services).

VoLTE is also known as VoIP (Voice over Internet Protocol), but VoIP is not only VoLTE. It includes WhatsApp, Viber, Skype and etc…We should not compare these applications with VoLTE, because VoLTE has large-scale resources.

A question: the user is using VoLTE call in LTE network and came to the LTE network edge, what will happen in this situation? Ok, there are two solutions:

1. The VoLTE call will make handover to CS domain of UTRAN or GERAN if VoIP service is not supported in target networks. This handover type is called SRVCC, with longer name Single Radio Voice Call Continuity.

2. The VoLTE call will make handover to PS domain of UTRAN or GERAN if VoIP service is supported in target networks.

Normally first case is possible.

SRVCC Overview

If a mobile operator wants to launch VoLTE service, then it needs to deploy IMS (IP Multimedia Subsystem) network with LTE. IMS includes multiple network elements:

IMS Overview

VoLTE uses Adaptive Multi-Rate (AMR) and Enhanced Voice Services (EVS) speech codecs:

AMR: this speech codec is widely used in UTRAN and GERAN networks. It is classified into AMR wideband (AMR-WB) and AMR narrowband (AMR-NB).

EVS: it allows to have HD VoLTE speech codec, and classified into EVS narrowband, EVS wideband, EVS superwideband, and EVS fullband.

The use of AMR or EVS is negotiated between UEs and IMS. This negotiation process is visible to the eNodeB.

There are two speech states for VoLTE:

Talk Spurts: during this period the UE sends or receive voice data packets. Voice packets are transmitted every 20 ms. Size of voice data packet depends on used speech coding rate.

Silent Periods: it means the UE doesn’t have any voice packets, in this period UE transmits or receives silence insertion descriptor (SID) frames. Interval is 160 ms for SID frames. The SID frame size is fixed to 56 bits for AMR speech codecs and 64 bits for EVS speech codecs.

Mean Opinion Score (MOS) is a measure of voice quality, here we can find quality values for VoLTE:

The post Voice over LTE appeared first on Telecompedia.

— There is a big office building with two blocks, different stairways. One of them is used to go upstairs and other one is used for downstairs. “The blocks and stairways are shown as uplink and downlink arrow directions on the LTE Radio Protocol Stack.”

On the first floor, different office engineers are sitting and receiving the products from the customers. “This floor name is Physical Layer. The engineers are Physical Channels.”

The engineers who are sitting on the first floor, control the products and forwards to upper floor which is second floor and other office engineers are sitting here. “The second floor name is MAC Layer. The engineers are Transport Channels.”

The engineers who are sitting on the second floor, check the received product from the first floor and makes decision to send it to upper floor and to which engineer. “The upper floor is RLC Layer and engineers are Logical Channels.”

The engineers in the third floor, check the received products and sends them to upper floor where specials experts are sitting who are responsible for security and other tasks. “This is fourth floor and name is PDCP Layer.”

The experts who are sitting on the fourth floor, inspect the received products from the third floor. There are two sub-floors after the fourth floor, so the experts check the products and distribute it to send upper floors. The pure product will be send to the “User Plane” floor and the box where the product was carried will be send to the “Control Plane” .

Above simple imagination was described from eNodeB to UE as “Product Receive”, for “Product Send” you can imagine as an opposite way.

LTE Protocol Stack consists of:

• Physical Layer
• MAC Layer
• RLC Layer
• PDCP Layer
• RRC Layer
• NAS Layer
• IP Layer
• Application Layer

— RRC and NAS layers are used for user signaling processing
— IP and Application layers are used for user traffic processing

The post LTE Radio Protocol Stack appeared first on Telecompedia.

Wireless communication systems should have a rapid solution to inform the people about natural disasters such as earthquake, tsunami or landslide. Currently one of the best notification solutions is ETWS for mobile users who are receiving pop-up messages on their phones’ screens. It is 3GPP specification. ETWS stands for “Earthquake and Tsunami Warning System”. The warning notification usually comes from local governments to mobile operators, and this messenger is called as CME (Cell Broadcast Entity). CME is not 3GPP specification and might be Seismology Agency or other broadcasting source.

CME can broadcast two kinds of notifications, Primary and Secondary.:

The primary message should be delivered to the subscribers within 4 seconds after generation of Cell Broadcast Entity and this is short message consists of urgent events such as “Earthquake”, “Tsunami” or “Earthquake + Tsunami”.

The secondary message may contain of some supplementary information such as epicenter, seismic intensity, magnitude and so on.

ETWS is available for GSM, WCDMA, LTE and 5G technologies

The cell broadcast service is mainly used to notify the subscribers about the disasters in GSM and WCDMA. Following radio channels are used for broadcasting:

CBCH: Cell Broadcast Channel in GSM
CTCH: Common Traffic Channel in WCDMA

In LTE, the subscribers are notified with system information messages:

“SystemInformationBlockType10” : carries Primary Notification message for ETWS
“SystemInformationBlockType11” : carries Secondary Notification message for ETWS

Overall primitive procedure for all technologies:

1. Cell Broadcast Entity notifies Cell Broadcast Centre about warning.
2. Cell Broadcast Centre forwards warning message to BSC, RNC or MME.
3. The warning message comes to BTS/NodeB/eNodeB through BSC/RNC/MME .
4. BTS, NodeB and eNodeB notifies the UEs with paging messages which will invoke user equipments to start receiving broadcasting information about warning.

The post Public Warning System (ETWS) appeared first on Telecompedia.

System Information Block Type 7 or with abbreviated version SIB7 contains GERAN frequency group related information and relevant only for cell re-selection from LTE to GSM. The message includes frequency groups with specific re-selection parameters. SIB7 is transmitted from the network to UE through BCCH -> DL-SCH -> PDSCH channels.

Here the list of carried information from the network to UE through SIB7:

t-Reselection GERAN: cell reselection timer for reselection to a GERAN frequency carrier. Value in seconds.
sf-Medium: specifies scaling factor for t-Reselection GERAN for inter-RAT reselection to GERAN in Medium-mobility state. Value oDot25 corresponds to 0.25, oDot5 corresponds to 0.5 etc.
sf-High: specifies scaling factor for t-Reselection GERAN for inter-RAT reselection to GERAN in High-mobility state. Value oDot25 corresponds to 0.25, oDot5 corresponds to 0.5 etc.

Carrier Freqs Info List GERAN: parameters related to a neighboring GERAN frequency group, these parameters are used for Inter-Technology reselection from EUTRAN to GERAN. The parameters might be different set for each frequency group.
Starting ARFCN: specifies first ARFCN in GERAN frequency group.
Band Indicator: specifies GERAN frequency band, either it is GSM1800 or GSM1900.
Explicit List Of ARFCNs: specifies the ARFCN list of the GERAN BCCH.
Cell Reselection Priority: indicates the cell reselection priority of GERAN frequency group. The value 0 indicates the lowest priority.
NCC-Permitted: field encoded as a bit map, where bit N is set to “0” if a BCCH carrier with NCC = N-1 is not permitted for monitoring and set to “1” if a BCCH carrier with NCC = N-1 is permitted for monitoring; N = 1 to 8; bit 1 of the bitmap is the leading bit of the bit string.
q-RxLevMin: required minimum received RSSI level on GERAN frequency carrier for re-selection from LTE to GSM. Actual value in dBm is value * 2 – 115.
Pmax: this parameter is used to limit the allowed UE uplink transmission power on this GERAN carrier frequency.
threshX-High: threshold used when reselecting from lower priority LTE frequency to higher priority GERAN frequency group. Actual value in dB is obtained by multiplying by 2.
threshX-Low: threshold used when reselecting from higher priority LTE frequency to lower priority GERAN frequency group. Actual value in dB is obtained by multiplying by 2.

SIB7 carried information:

Example for SIB7, taken from drive-test tool:

t-ReselectionGERAN : 1
t-ReselectionUTRA-SF
sf-Medium : lDot0
sf-High : oDot75
carrierFreqsInfoList
CarrierFreqsInfoListGERAN :
[0 ] :
carrierFreqs
startingARFCN : 515
bandIndicator : dcs1800
followingARFCNs :
explicitListOfARFCNs
ExplicitListOfARFCNs :
IntegerType = 520
IntegerType = 525
IntegerType = 530
IntegerType = 580
IntegerType = 585
IntegerType = 800
IntegerType = 855
cellReselectionPriority : 1
ncc-Permitted : 11111111
q-RxLevMin : 2
threshX-High : 7
threshX-Low : 8

* Note: there are some parameters which might not be seen in the message list from drive-test tool, so it means this parameter was not configured in the network by the engineers.

The post SIB7 in LTE appeared first on Telecompedia.

System Information Block Type 6 or with abbreviated version SIB6 contains UTRAN frequency related information and relevant only for cell re-selection from LTE to WCDMA. The message includes frequencies with specific re-selection parameters. SIB6 is transmitted from the network to UE through BCCH -> DL-SCH -> PDSCH channels.

Here the list of carried information from the network to UE through SIB6:

Carrier Freq List UTRA-FDD: contains information about UTRA FDD frequency carriers relevant for inter-RAT cell re-selection from E-UTRA to UTRAN FDD.
DL Carrier Freq: indicates the DL UARFCN of the neighboring cell on the UTRAN frequency.
Cell Reselection Priority: indicates the cell reselection priority of the neighboring UTRAN frequency. The value 0 indicates the lowest priority.
threshX-High: UTRAN high priority threshold, the threshold used when reselecting from a lower priority LTE frequency to higher priority UTRAN frequency. Actual value in dB is obtained by multiplying by 2.
threshX-Low: UTRAN lower priority threshold, the threshold used when reselecting from a higher priority LTE frequency to lower priority UTRAN frequency. Actual value in dB is obtained by multiplying by 2.
q-RxLevmin: required minimum received RSCP level on this UTRA frequency carrier. Actual value in dBm is obtained by multiplying by 2 plus 1.
q-QualMin: minimum quality level (EcNo) required for a cell on the UTRAN frequency to become a candidate for reselection.
p-MaxUTRA: this parameter is used to limit the allowed UE uplink transmission power on this UTRA FDD carrier frequency.
t-ReselectionUTRA: indicates the evaluation period for a UE to determine whether to reselect a neighboring UTRAN cell to camp on.
sf-Medium: specifies scaling factor for t-ReselectionUTRA for inter-RAT reselection to UTRA in Medium-mobility state. Value oDot25 corresponds to 0.25, oDot5 corresponds to 0.5 etc.
sf-High: specifies scaling factor for t-ReselectionUTRA for inter-RAT reselection to UTRA in High-mobility state. Value oDot25 corresponds to 0.25, oDot5 corresponds to 0.5 etc.

SIB6 carried information:

Example for SIB6, taken from drive-test tool:

systemInformation[0]BCCH-DLSCH-Message=
message = c1 = systemInformation =
criticalExtensions = systemInformation-r8 =
sib-TypeAndInfo = SEQUENCE OF CHOICE
CHOICE(1) = sib6 =
carrierFreqListUTRA-FDD = SEQUENCE OF
CarrierFreqUTRA-FDD (0) =
carrierFreq = 10787
cellReselectionPriority = 4
threshX-High = 2
threshX-Low = 1
q-RxLevmin = -58
p-MaxUTRA = 24
q-QualMin = -22
CarrierFreqUTRA-FDD (1) =
carrierFreq = 10787
cellReselectionPriority = 3
threshX-High = 6
threshX-Low = 6
q-RxLevmin = -58
p-MaxUTRA = 24
q-QualMin = -18
t-ReselectionUTRA = 1
t-ReselectionUTRA-SF
sf-Medium : lDot0
sf-High : oDot75

* Note: there are some parameters which might not be seen in the message list from drive-test tool, so it means this parameter was not configured in the network by the engineers.

The post SIB6 in LTE appeared first on Telecompedia.

System Information Block Type 5 or with abbreviated version SIB5 contains EUTRAN frequency related information and relevant only for inter-frequency cell re-selection. The message includes frequencies with specific re-selection parameters as well as blacklisted cells. SIB5 is transmitted from the network to UE through BCCH -> DL-SCH -> PDSCH channels.

Here the list of carried information from the network to UE through SIB5:

Inter Freq Carrier Freq List: contains information about inter-frequency cell re-selection within E-UTRAN.
dl-Carrier Freq: indicates target frequency EARFCN for inter-frequency cell re-selection.
q-RxLev Min: required minimum received RSRP level on this E-UTRA frequency carrier. Actual value in dBm is obtained by multiplying by 2.

p-Max: this parameter is used to limit the allowed UE uplink transmission power on this carrier frequency.
t-Reselection EUTRA: cell reselection timer for inter-frequency cell reselection to this E-UTRA frequency carrier.
sf-Medium: specifies scaling factor for t-Reselection EUTRA for inter-frequency reselection to this frequency carrier in Medium-mobility state. Value oDot25 corresponds to 0.25, oDot5 corresponds to 0.5 etc.
sf-High: specifies scaling factor for t-Reselection EUTRA for inter-frequency reselection to this frequency carrier in High-mobility state. Value oDot25 corresponds to 0.25, oDot5 corresponds to 0.5 etc.
threshX-High: inter frequency high priority threshold, the threshold used when reselecting from a lower priority LTE frequency to higher priority LTE frequency. Actual value in dB is obtained by multiplying by 2.
threshX-Low: inter frequency lower priority threshold, the threshold used when reselecting from a higher priority LTE frequency to lower priority LTE frequency. Actual value in dB is obtained by multiplying by 2.
Allowed Meas Bandwidth: indicates the measurement bandwidth of the inter-frequency neighboring cell on the frequency. A cell bandwidth is also expressed in units of physical resource blocks. Cell bandwidths 1.4 MHz, 3 MHz, 5 MHz, 10 MHz, 15 MHz, and 20 MHz correspond to 6 RBs, 15 RBs, 25 RBs, 50 RBs, 75 RBs, and 100 RBs.

Presence Antenna Port1: indicates whether all the inter-frequency neighboring cells are configured with at least two antenna ports:
– TRUE when all the inter-frequency neighboring cells are configured with at least two antenna ports.
– FALSE when one of the inter-frequency neighboring cells is configured with only one antenna port.

Cell Reselection Priority: inter-frequency cell re-selection priority indicates priority of the neighboring E-UTRAN frequency. The value 0 indicates the lowest priority.
Neigh Cell Config: provides the information related to MBSFN and TDD UL/DL configuration of inter-frequency neighbor cells:
– “00” inter-frequency neighboring cells have the same MBSFN sub-frame configuration as the serving cell.
– “01” none of the inter-frequency neighboring cells is configured with MBSFN sub-frames.
– “10” MBSFN sub-frame configurations of all inter-frequency neighboring cells are ame as the serving cell.
– “11” some inter-frequency neighboring cells have different UL-DL configurations from serving TDD cell.

q-Offset Freq: offset applicable between serving and this frequency carrier. Actual value in dBm is obtained by multiplying by 2. A larger value of this parameter results in a lower probability of reselection to cells on the neighboring E-UTRAN frequency. A smaller value of this parameter leads to the opposite effects.
Inter Freq Black Cell List: consists of the parameters related to a blacklisted inter-frequency cell.
Phys Cell Id: starting physical cell ID of the inter-frequency blacklisted cell.
Phys Cell Id Range: physical cell ID range of the inter-frequency blacklisted cell.

SIB5 carried information:

Example for SIB5, taken from drive-test tool:

interFreqCarrierFreqList
InterFreqCarrierFreqList :
[0 ] :
dl-CarrierFreq : 1524
q-RxLevMin : -60
p-Max : 23
t-ReselectionEUTRA : 1
threshX-High : 11
threshX-Low : 2
allowedMeasBandwidth : mbw75
presenceAntennaPort1 : False
cellReselectionPriority : 5
neighCellConfig
Binary string (Bin) : 01
[0 ] : 0
[1 ] : 1
[1 ] :
dl-CarrierFreq : 1475
q-RxLevMin : -60
p-Max : 23
t-ReselectionEUTRA : 1
threshX-High : 11
threshX-Low : 11
allowedMeasBandwidth : mbw50
presenceAntennaPort1 : False
cellReselectionPriority : 3
neighCellConfig
Binary string (Bin) : 01
[0 ] : 0
[1 ] : 1

* Note: there are some parameters which might not be seen in the message list from drive-test tool, so it means this parameter was not configured in the network by the engineers.

The post SIB5 in LTE appeared first on Telecompedia.

System Information Block Type 4 or with abbreviated version SIB4 contains neighboring cell related information and relevant only for intra-frequency cell re-selection. The message includes cells with specific re-selection parameters as well as blacklisted cells, Physical Cell Identities (PCI) for CSG. CSG can be used to support Home eNBs (Femto Cell). SIB4 is transmitted from the network to UE through BCCH -> DL-SCH -> PDSCH channels.

Here the list of carried information from the network to UE through SIB4:

Intra Freq Neigh Cell List: contains LTE cell neighbor list with specific parameters.
Phys Cell Id: indicates the physical cell ID of the intra-frequency neighbor cell.
q-Offset Cell: offset for the intra-frequency neighboring cell, which is used in evaluation for cell reselections. A larger value of this parameter results in a lower probability of cell reselections. If this parameter is not set to dB0, it is delivered in SIB4.
Intra Freq Black Cell List: consists of the parameters related to a blacklisted intra-frequency cell.
Phys Cell Id: starting physical cell ID of the intra-frequency blacklisted cell.
Phys Cell Id Range: physical cell ID range of the intra-frequency blacklisted cell.
CSG Phys Cell Id Range: Set of physical cell identities reserved for CSG cells. The received csg-PhysCellIdRange applies if less than 24 hours has elapsed since it was received and the UE is camped on a cell of the same primary PLMN where this field was received.

*Note: CSG (Closed Subscriber Group) is a group of users who are allowed for a specific cell (usually Femto cell). A CSG cell has restrictions on UE access. It broadcasts a specific CSG ID in the SIB and only those UEs of the group can access the CSG cell.

SIB4 carried information:

Example for SIB4, taken from drive-test tool:

systemInformation
criticalExtensions
systemInformation_r8
sib_TypeAndInfo
SystemInformation_r8_IEs_0_of_type
sib4
intraFreqNeighCellList
IntraFreqNeighCellInfo
physCellId = 0
q-OffsetCell = dB4
IntraFreqNeighCellInfo
physCellId = 1
q-OffsetCell = dB4
IntraFreqNeighCellInfo
physCellId = 2
q-OffsetCell = dB10
intraFreqBlackCellList
csg_PhysCellIdRange
nonCriticalExtension

The post SIB4 in LTE appeared first on Telecompedia.

System Information Block Type 3 or with shortened version SIB3 contains common information for Intra-Frequency, Inter-Frequency and Inter-Technology cell re-selection parameters. But these parameter values are not applied in all re-selection scenarios. SIB3 is transmitted from the network to UE through BCCH -> DL-SCH -> PDSCH channels.

Here the list of carried information from the network to UE through SIB3:

Cell Reselection Info Common:
q-Hyst: hysteresis value applied to serving cell for evaluating cell-reselection ranking criteria. It is for cell reselection when RSRP values are used in the evaluation.
t-Evaluation: specifies the duration for evaluation. Value in seconds.
t-Hyst Normal: the additional duration for evaluating criteria to enter normal mobility state. Specifies the additional time period for evaluating criteria to enter Normal-mobility state. Value in seconds, s30 corresponds to 30 seconds and so on.
n-cell Change Medium: specifies the number of cell reselections within t-Evaluation to enter Medium-mobility state.
n-cell Change High: specifies the number of cell reselections within t-Evaluation to enter High-mobility state.
sf-Medium: speed-dependent scaling factor for Qhyst in Medium-mobility state.
sf-High: speed-dependent scaling factor for Qhyst in High-mobility state.

Cell Reselection Serving Frequency Info:
s-NonIntra Search: measurement triggering threshold for inter-frequency and inter-RAT measurements with lower or equal priority. Actual value in dB is obtained by multiplying by 2.
Thresh Serving Low: threshold for serving frequency used in evaluation of reselection towards lower priority E-UTRAN frequency. Actual value in dB is obtained by multiplying by 2.
Cell Reselection Priority: cell reselection priority of the serving frequency. 0 indicates the lowest priority.

Intra-Freq Cell Reselection Info:
q-RxLev Min: minimum required received RSRP level for intra-frequency E-UTRA cell re-selection. Actual value in dBm is obtained by multiplying by 2.
p-Max: this parameter is used to limit the allowed UE uplink transmission power on the serving cell.
s-IntraSearch: indicates the measurement triggering threshold for reselection to intra-frequency cells.
Allowed Meas Bandwidth: indicates the measurement bandwidth on the serving frequency on which the UE camps. It is used in intra-frequency measurements for cell reselection.
Presence Antenna Port1: indicates whether all the intra-frequency neighboring cells are configured with at least two antenna ports:
– TRUE when all the intra-frequency neighboring cells are configured with at least two antenna ports.
– FALSE when one of the intra-frequency neighboring cells is configured with only one antenna port.

Neigh Cell Config: provides the information related to MBSFN and TDD UL/DL configuration of neighbor cells:
– “00” some neighboring cells have the same MBSFN sub-frame configuration as the serving cell.
– “01” none of the neighboring cells is configured with MBSFN sub-frames.
– “10” MBSFN sub-frame configurations of all neighboring cells are the same as the serving cell.
– “11” some neighboring cells have different UL-DL configurations from the serving TDD cell.

t-Reselection EUTRA: cell reselection timer for intra frequency E-UTRA cell reselection. Value in seconds.
sf-Medium: specifies scaling factor for intra-frequency t-Reselection EUTRA in Medium-mobility state. Value oDot25 corresponds to 0.25, oDot5 corresponds to 0.5 etc.
sf-High: specifies scaling factor for intra-frequency t-Reselection EUTRA in High-mobility state. Value oDot25 corresponds to 0.25, oDot5 corresponds to 0.5 etc.

SIB3 carried information:

Example for SIB3, taken from drive-test tool:

System Information Block 3
q-Hyst : dB4
s-NonIntraSearch : 2
threshServingLow : 1
cellReselectionPriority : 5
q-RxLevMin : -60
p-Max : 23
s-IntraSearch : 31
presenceAntennaPort1 : False
neighCellConfig
Binary string (Bin) : 01
[0 ] : 0
[1 ] : 1
t-ReselectionEUTRA : 1
t-ReselectionEUTRA-SF
sf-Medium : lDot0
sf-High : oDot75

* Note: there are some parameters which might not be seen in the message list from drive-test tool, so it means this parameter was not configured in the network by the engineers.

The post SIB3 in LTE appeared first on Telecompedia.

After initial synchronization of UE with the network and obtaining the MIB, the UE starts to listen System Information Block Type 1 (SIB1) which is carrying cell access related information. SIB1 is transmitted through BCCH -> DL-SCH -> PDSCH channels. It is always sent in sub-frame #5 of the Radio-Frame, and continues re-transmitting the same message in each 20 ms with different redundancy versions. Each 80ms a new SIB1 is transmitted.

Here the list of carried information from the network to UE through SIB1:

PLMN Identity List: up to 6 PLMN can be identified in the list. First one is primary PLMN.
PLMN Identity: identifies operator global identity, combination of MCC and MNC.
Cell Reserved For Operator Use: Reserved or notReserved. In case of multiple PLMNs indicated in SIB1, this field is specified per PLMN inverse of *Cell Barred.
Tracking Area Code: identifies a tracking area for paging the users.
Cell Identity: identifies a cell within PLMN.

*Cell Barred: identifies the cell access status, if it is barred then it is not allowed the user to access to the cell. In case of multiple PLMNs listed in SIB1, this field is common for all PLMNs.
Intra Frequency Reselection: identifies the intra-frequency reselection permission status if it is allowed or not.
CSG Indication: False or True, identifies Closed Subscriber Group.
CSG Identity: is a limited set of users with connectivity access, in case of “true” only those UEs can access to the CSG cell which are in the group.
q_RxLevMin: minimum required received RSRP level for cell selection. Actual value in dBm is obtained by multiplying by two.
q_RxLevMinOffset: indicates the offset to the minimum required signal level.
p-Max: defines the maximum allowed uplink transmit power for the UE.
Freq Band Indicator: indicates LTE frequency band.
SI Periodicity: periodicity of System Information Blocks except than SIB1.
SIB Mapping Info: list of mapped SIBs.
SIB Type: type of transmitted SIB message in the list.
SI Window Length: a window is defined to enable multiple transmissions of the SI message within the window. SI Window Length can be set to 1, 2, 5 10, 15, 20 or 40 ms.
System Info Value Tag: if a change has occurred in the SI messages. UEs can use System Info Value Tag to verify if the previously stored SI messages are still valid.

SIB1 carried information:

Example for SIB1, taken from drive-test tool:

plmn-IdentityList
PLMN-IdentityList :
[0 ] :
plmn-Identity
mcc
MCC :
[0 ] : 1
[1 ] : 1
[2 ] : 1
mnc
MNC :
[0 ] : 0
[1 ] : 2
cellReservedForOperatorUse : notReserved
trackingAreaCode : 38441 (0x9629)
cellIdentity : 113491462 (0x6C3BE06)
cellBarred : notBarred
intraFreqReselection : allowed
csg-Indication : False
q-RxLevMin : -60
p-Max : 23
freqBandIndicator : 3
schedulingInfoList
SchedulingInfoList :
[0 ] :
si-Periodicity : rf16
sib-MappingInfo
SIB-MappingInfo :
[0 ] :
extensionBit0 : 0
Optionalitem : sibType3
[1 ] :
si-Periodicity : rf32
sib-MappingInfo
SIB-MappingInfo :
[0 ] :
extensionBit0 : 0
Optionalitem : sibType5
si-WindowLength : ms40
systemInfoValueTag : 8

The post SIB1 in LTE appeared first on Telecompedia.

“Block Error Rate” or BLER is a measurement type of quality in telecommunication. Simple calculation of the measurement:

BLER (in LTE) = Number of erroneous blocks / total number of received blocks

The calculation is based on CRC (Cyclic Redundancy Check) evaluation which is used for inspection the transport blocks at receiver side. CRC is attached to each transport block and sending by the transmitter, at the destination the transport block is cross checked by the receiver. The transport block is successfully decoded if the attached CRC is matching the CRC calculated by the receiver.

The CRC is a technique used to detect errors in transport blocks.

If the calculation gives undesired result then the receiver will feedback with HARQ NACK message for asking re-transmission. In radio side, typical BLER target is 10% which means the receiver should receive at least 90% successful transmission. If the target is less than 10% then more re-transmission might be required and cause radio resource consuming.

“Error” is unavoidable in wireless communication due to several reasons.

In many radio measurement tools, we can see two kinds of BLER: iBLER and rBLER

iBLER: Initial Block Error Rate
The ratio of data blocks with initial transmission errors to all initial transmission data blocks.

rBLER: Residual Block Error Rate
The ratio of data blocks with transmission errors after initial transmissions and retransmissions to all initial transmission data blocks.

The post Block Error Rate in LTE appeared first on Telecompedia.