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“where LTE will lead, we know not; but we can be sure that it will not be the last development in wireless telegraphy” – Guglielmo Marconi

[1] LTE KEY FEATURES
 MIMO INTRODUCTION
 CSFB (CIRCUIT-SWITCH FALL BACK)
 SON (SELF ORGANIZING NETWORKS)
 IDLE MODE BEHAVIOR
 CONNECTED MODE (HO via X2,S1 and IRAT HO)
[2] RF OPTIMISATION
 RF OPTIMISATION CONCEPT
 RF GUL COMPARISION
 DRIVE TEST KPIS
 COVERAGE PROBLEM CASEs
 RF OPTIMISAITION SOLUTIONs
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Contents (DAY2)

[1] LTE MIMO (Multiple Input Multiple Output)
 LTE specifications support the use of multiple antennas at both transmitter (tx) and receiver (rx). MIMO (Multiple Input Multiple
Output) uses this antenna configuration.
 LTE specifications support up to 4 antennas at the tx side and up to 4 antennas at the rx side (here referred to as 4x4 MIMO
configuration).
In the first release of LTE it is likely that the UE only has 1 tx antenna, even if it uses 2 rx antennas. This leads to that so called
Single User MIMO (SU-MIMO) will be supported only in DL (and maximum 2x2 configuration).
 OFDM works particularly well with MIMO
– MIMO becomes difficult when there is time
dispersion
– OFDM sub-carriers are flat fading (no time
dispersion)
 3GPP supports one, two, or four transmit Antenna Ports
 Multiple antenna ports
 Multiple time-frequency grids
 Each antenna port defined by an associated Reference
Signal
Multiple layers means that the time- and frequency resources (Resource Blocks) can be reused in the different layers up to a
number of times corresponding to the channel rank. This means that the same resource allocation is made on all transmitted
layers.
4

*Beam forming
5

DL Single User MIMO –with 2 antennas
6

UL Multi user MIMO (virtual MIMO)
7

[2]CSFB (CIRCUIT SWITCHED FALLBACK )

Network Architecture for CS Fallback to UTRAN/GERAN
SGs
To support CS Fallback, the SGs interface is required, so as to let the MME perform a UE location update over the SGs
interface so that the core network of the UTRAN or GERAN learns about the UE location.
10

Combined EPS/IMSI Attach Procedure
 After a UE is powered on in the E-UTRAN, it initiates a combined EPS/IMSI attach procedure.
 If a UE is camping on an E-UTRAN cell, it periodically initiates a combined TAU/LAU procedure, which allows for simultaneous UE.
location updates both in the MME and in the core network of the UTRAN or GERAN.
 After the RRC connection setup, the UE sends an Attach
Request message to the MME, requesting a combined
EPS/IMSI attach procedure. This message also indicates
whether the CS Fallback or SMS over SGs function is required.
 The MME allocates an LAI to the UE, and then it finds the
MSC/VLR for the UE based on the TAI-LAI mapping.
The MME sends the MSC/VLR a Location Update Request
message over the SGs interface so that the core network of
the UTRAN or GERAN learns about the UE location, which
contains the new LAI, IMSI, MME name, and location update
type.
The MSC/VLR performs the location update procedure in the
CS domain.
The MSC/VLR responds with a “Location Update Accept”
message that contains information about the VLR and
temporary mobile subscriber identity (TMSI). The location
update procedure is successful.
The UE is informed that the combined EPS/IMSI attach
procedure is successful by RRC Connection Reconfiguration
message.
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For CSFB, eNB performs decisions in the following steps:
Triggering phase
•Decides whether to perform CS Fallback in the form of a blind handover.
(Compared with measurement-based CS Fallback, blind handovers（blind redirection) have shorter
access delays but a lower handover success rate. Measurement phase)
•Measurement phase
•Decides and delivers the inter-RAT measurement configuration to the UE.
•Decision phase
•Evaluates the measurement results and determine the target cell.
•Execution phase
•Selects a CSFB mechanism from PS HO, PS Redirection, flash CSFB or CCO/NACC .
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[2] CSFB (CIRCUIT SWITCHED FALLBACK )
Based on the capabilities of UEs and networks, the following mechanisms are available for an eNB to perform CS Fallback to UTRAN.
CS Fallback based on PS redirection
Flash CS Fallback(with RIM)
CS Fallback based on PS handover
Flash CS Fallback(Blind handover)
UE sends the MME an NAS message Extended Service
Request to initiate a CS service.
The MME sends an S1-AP Request message to instruct the
eNB to initiate a CS Fallback procedure.
The eNB determines whether to perform a blind redirection
based on the setting(BlindHoSwitch under the
HoModeSwitch parameter)
The eNB sends an RRC Connection Release message to
instruct the UE to perform a redirection. The message contains
information about a target UTRAN frequency.
If flash CS Fallback is available, the RRC Connection
release message includes information about a target
UTRAN frequency, PSC and their associated system
information, In this way, the UE can quickly access the
target UTRAN without the need to perform the
procedure for acquiring system information of the
target UTRAN cell. Then, the UE can directly initiate a
CS service in the UTRAN cell.
eNB initiates an S1 UE context release procedure.
UE may initiate an LAU, a combined RAU/LAU, or both an
RAU and an LAU in the target cell and initiates a CS call
establishment procedure in the target UTRAN cell.
CS Fallback based on PS redirection
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RAN Information Management (RIM) Procedure
 To support Flash CS Fallback, eNB requires exchange information between E-UTRAN and GERAN/UTRAN through the core networks.
 Flash CS Fallback is defined in 3GPP R9 .With this function, SIB can be included into the ”RRC connection Release” during the redirection
procedure. This is achived by the RIM procedure. with RIM, eNB can get information from GERAN/UMTS.
 The RIM procedure supports two information exchange modes: Single Report and Multiple Report. In Single Report mode, the source sends a
request, and then the target responds with a single report. In Multiple Report mode, the target responds with a report after receiving a request
from the source, and it also sends a report to the source each time the system information changes.
 The Multiple Report mode is enabled or disabled by setting the RimSwitch parameter, while the Single Report mode is not configurable.
Flash CSFB (R9 Redirection with SIB)
*** SRVCC : Voice (IP) to UMTS, improve the Voice call
setup delay. 14

CS Fallback Based on PS Handover(UMTS) - * CN/RNC need to support
 UE sends the MME an NAS message
Extended Service Request to initiate a CS
service.
 The MME sends an S1-AP Request message
to instruct the eNB to initiate a CS Fallback
procedure (If the MME supports the LAI-
related feature, the MME also delivers the LAI
to the eNB).
The eNB determines whether to perform a
blind handover based on the setting of
BlindHoSwitch under the HoModeSwitch
parameter.
The eNB initiates the preparation phase for a
PS handover. If the preparation is successful,
the eNB instructs the UE to perform a
handover.
After the handover, the UE may initiate an
LAU or combined RAU/LAU procedure in the
UTRAN.
The UE’s context in EPS is released.
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CS Fallback Procedure for Terminated Calls (UMTS)
The MSC sends a Paging Request message from
the CS domain to the MME over the SGs interface.
Then, either of the following occurs:
If the UE is in idle mode, the MME sends a
Paging message to the eNB. Then the eNB
sends a Paging message over the Uu
interface to inform the UE of an incoming
call from the CS domain, then UE initiates a
connection establish procedure.
If the UE is in active mode（connected）,
the MME sends the UE an NAS message to
inform the UE of an incoming call from the
CS domain.
The UE sends an Extended Service Request
message containing a CS Fallback Indicator after
receiving the paging message from the CS domain.
The MME instructs the eNB over the S1 interface
to perform CS Fallback.
The subsequent steps are similar to the
originated CS Fallback to UTRAN.
The service request message from the UTRAN cell
to UMTS CN is considered as the Paging Response
message.
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[3]SON (SELF ORGANIZING NETWORKS)
 Operation and maintenance (OM) of radio access networks has become increasingly complicated difficult, and costly
because of the large number of network elements, implementation of different system standards, and coexistence of
different equipment vendors and telecom operators.
 To meet these challenges, Self-Organizing Network (SON) solution is introduced in 3GPP Release 8.
 The main functions of SON are self-configuration, self-optimization, and self-healing.
 Three SON RRM functionalities have been standardized in Rel 8.
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[3]SON_ANR (Automatic Neighbor Relation)
ANR automatically detects and adds missing neighboring cells. In addition, it identifies and removes incorrect or redundant neighboring cells. ANR
minimizes the impact of missing neighboring cells, physical cell identifier (PCI) conflicts, and abnormal neighboring cell coverage so as to increase
handover success rates.
ANR automatically maintains the completeness and validity of neighbor cell lists (NCLs) and neighbor relation tables (NRTs) to increase handover success
rates and improve network performance. In addition, ANR reduces manual intervention and, therefore, the costs of network planning and optimization.
(X2 self-setup and automatic removal reduces manual intervention and O&M costs).
ANR is classified based on Radio Access Technologies (RATs) as either intra-RAT ANR or inter-RAT ANR. It is further classified based on the methods used
to measure neighboring cell activity, specifically event-triggered ANR or fast ANR (also known as periodic ANR).
 Main ANR management functions:
 Automatic detection of missing neighboring cells
 Automatic evaluation of neighbor relations
 Automatic detection of Physical Cell Identifier (PCI)
collisions
 Automatic detection of abnormal neighboring cell
coverage
 Automatic Neighbor Relation (ANR) can automatically add and
maintain neighbor relations. The initial network construction,
however, should not fully depend on ANR for the following
considerations:
 ANR is closely related to traffic in the entire network.
 ANR is based on UE measurements but the delay is
introduced in the measurements.
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SN LCI TCI No Remove No HO
1 LCI#1 TCI#1 True True
2 LCI#1 TCI#2 False False
3 LCI#1 TCI#3 True True
 NCL(Neighbor Cell List) contains the information about the neighboring cells of a serving cell. NCLs are classified into intra-RAT
NCLs, inter-RAT NCLs. Each cell has an intra-RAT NCL and inter-RAT NCLs.
NCL includes the E-UTRAN Cell Global Identifiers(or CGIs for inter-RAT), PCIs, TAC, eNB ID and E-UTRA Absolute Radio Frequency
Channel Numbers (EARFCNs) of the neighboring cells.
•NRT(Neighbor Relations Table) contains the information about the neighbor relations between the source cell and its
neighboring cells. NRTs are classified into intra-RAT NRTs and inter-RAT NRTs. Each cell has an intra-RAT NRT, inter-RAT NRTs.
HO blacklist contains the information about neighbor relations that cannot be removed automatically
from the NRT by ANR or used for a handover. The neighbor relations in the HO blacklist must meet the
following conditions:
•NO Remove = TRUE
•NO HO = TRUE
HO white list contains the information about neighbor relations that cannot be removed automatically
from the NRT by ANR but can be used for a handover. The neighbor relations in the HO white list must
meet the following conditions:
•NO Remove = TRUE
•NO HO = FALSE 20

• The source eNB delivers the measurement configuration to the UE, instructing
the UE to measure neighboring cells as specified in the measurement
configuration.
•The UE performs intra-frequency measurements by default. When a UE
establishes radio bearers, by default, the eNB delivers the intra-frequency
measurement configuration to the UE in an RRC Connection Reconfiguration
message.
•When inter-frequency measurements are required, the eNB must deliver the
inter-frequency measurement configuration to the UE and set up inter-frequency
measurement gaps.
•The UE detects that cell B meets the measurement requirements, and it reports
the PCI of cell B to the source eNB.
(Note that the UE does not report the PCIs of the neighboring cells in the RRC
blacklist to the eNB).
• The source eNB checks whether its intra-RAT NCL includes the PCI of cell B. If
the NCL includes this PCI, the ANR procedure ends.
•If the NCL does not include this PCI, the source eNB sends the
measurement configuration to the UE, instructing the UE to read the
ECGI, tracking area code (TAC), and PLMN list of cell B.
•The source eNB enables the UE to read these parameters over the
broadcast channel (BCH).
•UE reports the obtained parameter values (E-CGI) to the source eNB. The source
eNB adds the newly detected neighboring cell (cell B) to its intra-RAT NCL and
adds the neighbor relation to an intra-RAT NRT of cell A.
Cell PCI ECGI
Cell A 3 17
Cell B 5 19
Missing Neighbor Detection & Add
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• A PCI collision means two cells in an NCL have the same PCI but different
ECGIs. PCI collisions may be caused by improper network planning or
abnormal neighboring cell coverage. If two neighboring cells have the same
PCI, interference will be caused.
•After adding a neighbor relation to its intra-RAT NRT, the eNB compares the
PCI of the new neighboring cell with the PCIs of existing neighboring cells. If
the new neighboring cell and any existing neighboring cell have different
ECGIs but the same PCI, the eNodeB reports PCI collisions to the M2000.
•The M2000 collects statistics about PCI collisions, generates a list of
information about PCI collisions, and reports PCI collision alarms.
•PCI reallocation is a process of reallocating a new PCI to a cell whose PCI
collides with the PCI of another cell. The purpose is to eliminate PCI
collisions. The M2000 triggers the PCI reallocation algorithm to provide
suggestions on PCI reallocation.
PCI Collision Detection & Solve
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Abnormal Neighbor Coverage Trigger
Abnormal neighboring cell coverage refers to the coverage of a cell that is not adjacent to the serving cell but can be
detected by a UE in the serving cell.
Abnormal neighboring cell coverage decreases the handover success rate because of abnormal neighbor relations it has
introduced. Therefore, detecting and eliminating abnormal neighboring cell coverage play an important role in network
optimization.
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[4] IDLE MODE BEHAVIOR
Four different reasons for camping on a cell in the Idle mode were identified in the specifications:
 UE is capable to read the system information, which is broadcasted on the PBCH and PDSCH. Hereby, the UE gains
also information of the serving PLMN.
 If the access to the current cell is not barred, then the UE can use the cell to initiate an RRC (signalling) connection.
The access network is accessed by common control channels (PRACH) to access the network. Initial access is done to
register the UE at the network. Other reasons for accessing the network is to request transmission resources for user
data transfer.
 If the UE is registered, and there is a mobile terminated call, the serving core network elements know (in most cases)
the Tracking area (TA), in which the UE is camping. Paging is done with the common control channel PCH.
The idle mode tasks are divided into the following :
PLMN selection
Cell search & selection
Cell reselection
TA update
Periodic paging monitoring
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[4] IDLE MODE BEHAVIOR
Camping on a cell is necessary for the UE to get access to some services in the network.
The following three types of services are defined for the UE in Idle mode:
Limited service, which allows the UE to make emergency calls only on an acceptable cell.
Normal service, for public use on a suitable cell
Operator-related services, which allow the operator to test newly deployed cells without being disturbed by normal traffic.
An "acceptable cell" is a cell on which the UE may camp to obtain limited services (originate emergency calls). Such a cell fulfils the following requirements,
which is the minimum set of requirements to initiate an emergency call in a UTRAN network:
The cell is not barred.
The cell selection criteria are fulfilled.
A "suitable cell" is a cell on which the UE may camp on to obtain normal service.
Such a cell fulfils all the following requirements.
The cell is part of the selected PLMN or, of the registered PLMN or, the equivalent PLMN.
The cell is not barred.
The cell is not part of the list of "forbidden LAs for roaming".
The cell selection criteria are fulfilled.
A “barred cell” is a cell that is restricted (barred) to camp on for all access classes.
A “reserved cell” is a cell that has been reserved for operator use where only UEs with USIM access class 11 or 15 can camp on.
This is indicated on SIB 1.
The operator can establish cell access restrictions using the CellReservedForOp parameter that allows the reservation
of a cell for operator use only. It is also possible to restrict access for certain Access Classes (AC).
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[4] IDLE MODE BEHAVIOR - PLMN Selection
Whenever a UE is switched on or enters an area with acceptable coverage after coverage loss,
it attempts to camp on the last registered PLMN (RPLMN) or equivalent PLMN (EPLMN), if available.
To speed up the PLMN selection procedure, the UE uses information about the last registered PLMN, such as carrier frequencies or the list of neighboring
cells stored in the USIM before the UE was switched off. On each stored carrier frequency, the UE searches first for the strongest signal cell and reads its
system information to verify the PLMN to which the cell belongs.
It also reads the system information for PLMN identity, which consists of mcc and mnc. Then the UE decides whether the chosen cell is acceptable or
whether at least one acceptable cell belonging to that PLMN exists. Finally, the UE attempts registration if the PLMN is allowed.
If the last registered PLMN is not available, a registration attempt fails. If there is no registered PLMN stored in the USIM, the UE selects and attempts
registration on other PLMNs using either the Automatic mode or the Manual mode.
 RPLMN
The Registered PLMN (RPLMN) records LA and RA information. RPLMN is saved in EFLOCI and EFPSLOCI folders in USIM.
 HPLMN
The Home PLMN are the PLMNs of which the MCC and MNC are the same as that in the IMSI of the UE, it is the PLMN that the UE subscribed.
HPLMN can be obtained from EFIMSI folder in USIM.
 EPLMN
The Equivalent PLMN, indicating the PLMN that can provide the same services for users as the current network.
 VPLMN
The Visitor PLMN, indicating the PLMN that the UE camps on except the HPLMN and EPLMN
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Automatic PLMN selection mode
In Automatic mode, if no last registered PLMN exists or is
available, the UE will select a PLMN that is available and allowed,
in the following order:
1. Home PLMN (HPLMN), if not previously selected, according to
the Radio Access Technologies (RATs) supported by the UE.
2. Each PLMN in the user-controlled PLMNs list in the USIM, if
present, in order of priority, according to the RATs supported
by the UE.
3. Each PLMN in the operator-controlled PLMNs list in the USIM,
in order of priority, according to the RATs supported by the UE.
4. Other PLMNs, according to the high-quality criterion, in
random order.
5. Other PLMNs that do not fulfill high-quality criterion, in order
of decreasing signal strength (SS).
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Manual PLMN selection mode
The Manual mode allows the user to select a PLMN among those indicated by the UE.
The UE displays all PLMNs that it finds by scanning all frequency carriers. The UE displays those PLMNs that are allowed as well as those that are not
allowed. The user makes a manual selection, according to the available access technology for the chosen PLMN, and the UE attempts registration on this
PLMN, ignoring the contents of the forbidden Location Area Identities (LAIs) and PLMN lists.
If the user selects an available PLMN in the forbidden PLMN list, the UE attempts to register and may receive a positive acknowledgement from the CN. In
this case, the PLMN is removed from the forbidden list.
If the user does not select a PLMN, the selected PLMN is the one that was selected before the PLMN selection procedure started. If this PLMN is no longer
available, the UE attempts to camp on an acceptable cell at any PLMN and enters the limited service state. The UE remains in that state until it is switched
off or the user makes a manual PLMN reselection.
Roaming
Roaming is a service through which a UE is able to obtain services from another PLMN in the same country (national roaming area) or another country
(international roaming area).
In many countries, the regulation authority enforced national roaming of UMTS subscribers in existing GSM networks in order to grant a higher coverage
to UMTS subscribers.
If national roaming is allowed, the UMTS operator wants to avoid unnecessary roaming fees. In this case the UE do PLMN reselection.
The MCC is the same in VPLMN and HPLMN while MNC is different , UE must periodically search for the HPLMN. The “HPLMN Search Period” (EFHPLMN)
timer, a value of T minutes may be stored in the SIM. Either T is in the range 6 minutes to 8 hours with a step of 6 minutes or T indicates that no periodic
attempts shall be made. If no value is stored in the SIM, a default value of 60 minutes is used.
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[4] IDLE MODE BEHAVIOR - Cell Search & Cell Selection
Cell searching
Reads the
broadcast
channel
PLMN selection
Cell
Selection
Criteria
Obtains the
information of the cell
Camped
Normally
If the UE meets the
Cell selection
criteria
If the UE does not meet the cell
selection criteria, it camp in the
original cell and keeps searching
camp on any cell,
and calls are
restricted
The cell is not
under the PLMN
Determines the PCI
of the cell
Keeps
searching
The cell selection and reselection process allows the UE to look for a suitable cell in the selected PLMN and to camp on it.
The UE then camps on the suitable cell in a “camped normally” state. In this state, the UE monitors paging and system information,
performs periodical radio measurements, and evaluates cell reselection criteria.
If the UE finds a better cell, that cell is selected by the cell reselection process. The change of cell may imply a change of the RAT.
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Qrxlevmeas is the measured RX signal level (RSRP value) of the cell (dBm).
Qrxlevmin is the lowest cell RX signal level. It is broadcast in the SIB1.
Qrxlevminoffset is the offset to Qrxlevmin. It is broadcast in the SIB1. In addition to cell
selection, this offset is taken into account when the UE attempts to camp on a cell in a
higher-priority PLMN. That is, when camped on a cell in a VPLMN, the UE considers this
offset parameter, which was delivered by the cell in the higher-priority PLMN.
Pcompensation is the result of the function: max (PMax - UE Maximum Output Power, 0).
•PMax is the maximum transmit power that the UE can apply to uplink
transmission. It is broadcast in the SIB1.
•UE Maximum Output Power is the maximum output power that the UE can
physically achieve. It is un-configurable on the network side (Typically 23dBm).
Qqualmeas is the measured RX signal quality (RSRQ value) of the cell.
QqualMin is the lowest cell RX signal quality required for the cell to become a suitable cell.
It is broadcast in the SIB1.
QqualMinOffset is the offset to QqualMin. It is broadcast in the SIB1. In addition to cell
selection, the UE camped on a cell in a VPLMN considers this offset parameter when it
attempts to camp on a cell in a higher-priority PLMN. The cell in the higher-priority PLMN
delivers the value of this parameter to the UE for the Squal evaluation.
[4] IDLE MODE BEHAVIOR -Cell Selection
Srxlev > 0 and Squal > 0
Srxlev = Qrxlevmeas - (Qrxlevmin + Qrxlevminoffset) - Pcompensation
Squal = Qqualmeas - (QqualMin + QqualMinOffset)
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4] IDLE MODE BEHAVIOR -Cell Barring & Reservation
UEs are notified of cell status by the following information in the SIB1:
cellBarred :cell barring status. If a cell belongs to multiple PLMNs, this information is common for all PLMNs.
cellReservedForOperatorUse : whether a cell is reserved for an operator. This information is PLMN-specific.
UEs are notified of cell status by the following information in the SIB1:
If a cell is neither barred nor reserved for operator use, UEs can consider this cell as a candidate during cell selection and reselection procedures.
If a cell is not barred but is reserved for operator use, UEs treat this cell during cell selection and reselection procedures as follows:
If UEs of access class 11 or 15 camp on their HPLMN or an EHPLMN, the UEs can treat this cell as a candidate.
Otherwise, UEs treat this cell as a barred cell.
If a cell is barred, UEs behave as follows during cell selection and reselection procedures:
The UEs cannot select or reselect this cell, not even for emergency calls.
The UEs select another cell as follows:
When intraFreqReselection in the SIB1 indicates that intra-frequency reselection is allowed, the UEs may select another cell on the same
frequency if reselection criteria are fulfilled. When intraFreqReselection in the SIB1 indicates that intra-frequency reselection is not allowed,
the UEs do not reselect a cell on the same frequency as the barred cell. The value of intraFreqReselection in the SIB1 is specified by the
CELLACCESS.IntraFreqResel parameter.
The UEs exclude the barred cell as a candidate for cell selection or reselection for 300 seconds.
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[4] IDLE MODE BEHAVIOR -Cell Reselection
The signal strength of both serving cell and neighboring cells varies with the movement of a UE and so the UE needs to select the most suitable cell to
camp on. This process is called cell reselection which is considered as UE mobility management in idle mode
Cell reselection process:
Measurement start criteria
Cell reselection criteria (Rank the measured cells based on radio signal quality and priorities)
Frequency Priority Handling for Measurement
 For intra-frequency neighbor measurement: The priority is the same between source cell and neighbor cell, so UE will ignore it.
 For inter-frequency and inter-RAT neighbor measurement: UE will take the priority between source cell and neighbor cell for the measurement
Frequencies of different RATs must have different priorities.
 The priorities of E-UTRAN frequencies and inter-RAT frequencies are classified into the following types:
 Absolute priority: This priority is specified by the CellReselPriority parameter and is sent to UEs through broadcast of system information.
 4G Serving cell frequency priority will be delivered in SIB3,
 4G Inter-frequency priority will be delivered in SIB5,
3G frequency priority will be delivered in SIB6 and 2G frequency priority will be delivered in SIB7.
* A larger value of this parameter indicates a higher probability of a UE camping on the cells assigned with the same frequency as the serving one, and a smaller
value indicates a lower probability.
 Dedicated priority: The dedicated priority of an E-UTRAN or inter-RAT frequency is UE-specific. It is delivered to the UE in an RRC Connection
Release message when the UE's radio resources are released.
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If the intra frequency measurement triggering threshold is not configured, the UE always performs intra frequency measurements.
If the intra frequency measurement triggering threshold is configured:
Srxlev > SIntraSearch and Squal > SIntraSearchQ the UE dose not perform intra frequency measurement
Srxlev ≤SintraSearch or Squal ≤ SIntraSearchQ, the UE perform intra frequency measurement
Intra-Frequency Measurement Criteria
For the neighbors with higher priority
The UE always perform inter frequency /RAT measurement.
For the neighbor with lower or equal priority
If the threshold is not configured, the UE always perform inter frequency/RAT measurement
If the threshold is configured :
When Srxlev > SNonIntraSearch and Squal > SNonIntraSearchQ, UE does not perform inter frequency/RAT measurement
When Srxlev ≤ SnonIntraSearch or Squal ≤ SNonIntraSearchQ UE perform inter frequency /RAT measurement
Inter-Frequency /IRAT Measurement Criteria
33

A UE makes a cell reselection decision according to cell reselection criteria. When making a decision on reselection to an intra
frequency or equal-priority inter frequency cell, the UE checks whether the signal quality of a neighboring cell is higher than that of
the serving cell.
The cell-ranking criteria R_s for the serving cell and R_n for neighboring cells are defined as follows:
R_s = Qmeas,s + Qhyst
R_n = Qmeas,n - CellQoffset
Where:
Qmeas_s is the measured RSRP of the serving cell, expressed in units of dBm
Qhyst is the hysteresis for the serving cell used in the ranking criteria, expressed in units of dB.
Qmeas_n is the measured RSRP of the neighboring cell, expressed in units of dBm
CellQoffset is the offset for the neighboring cell used in the ranking criteria, expressed in units of dB
According to the cell reselection criteria, the UE should reselect the new cell only if both the following conditions are met:
The new cell is ranked higher than the serving cell during the cell reselection time.
More than one second has elapsed since the UE camped on the serving cell.
Intra Frequency/ Equal-Priority Cell Reselection Criteria
34

For EUTRAN and UTRAN, either Srxlev or Squal could be used for cell reselection, depends on the following parameter:
If ThrshServLowQCfgInd is set “CFG”,than it use Squal
Otherwise, it use Srxlev
For GERAN, it only uses Srxlev
Srxlev and Squal evaluation is the same as cell selection algorithm.
 If SIB3 contains the value of ThrshServLowQ, a UE performs reselection to a higher-priority inter-frequency or inter-RAT neighboring cell when both the
following conditions are met:
The neighboring cell has one of the following measurement results:
The Squal value of the evaluated neighboring E-UTRAN or UTRAN cell is always greater than the RX signal quality threshold used in
reselection to higher-priority cells (ThreshXHighQ) during the cell reselection time specified by the TReselEutran or TReselUtran parameter.
The Srxlev value of the evaluated neighboring GERAN or CDMA2000 cell is always greater than the RX signal level threshold used in
reselection to higher-priority cells (ThreshXHigh) during the cell reselection time specified by the TReselGeran or Cdma1XrttTreselection
parameter
The UE has camped on the serving cell for more than 1 second.
If SIB3 does not contain the value of ThrshServLowQ, a UE performs reselection to a higher-priority inter-frequency or inter-RAT neighboring cell when
the following conditions are both met:
The Srxlev value of the evaluated neighboring cell is always greater than the ThreshXHigh value during the predefined cell reselection time.
The UE has camped on the serving cell for more than 1 second.
High Priority Cell Reselection Criteria
35

[4] IDLE MODE BEHAVIOR - Cell Reselection
If SIB3 contains the value of ThrshServLowQ, a UE performs reselection to a lower-priority inter-frequency or inter-RAT neighboring
cell when all the following conditions are met:
No cell meets the criteria for reselection to higher-priority cells
The Squal value of the serving cell is always less than the RX signal quality threshold for the serving cell used in reselection to lower-priority cells
(ThrshServLowQ) during the predefined cell reselection time.
The neighboring cell has one of the following measurement results:
The Squal value of the evaluated neighboring E-UTRAN or UTRAN cell is always greater than the RX signal quality threshold used in
reselection to lower-priority cells (ThreshXLowQ) during the predefined cell reselection time.
The Srxlev value of the evaluated neighboring GERAN or CDMA2000 cell is always greater than the RX signal level threshold used in
reselection to lower-priority cells (ThreshXLowQ) during the predefined cell reselection time.
The UE has camped on the serving cell for more than 1 second
If SIB3 does not contain the value of ThrshServLowQ, a UE performs reselection to a lower-priority inter-frequency or inter-RAT cell when all the
following conditions are met:
No cell meets the criteria for reselection to higher-priority cells
The Srxlev value of the serving cell is always less than the RX signal level threshold for the serving frequency used in reselection to lower-priority
cells (ThrshServLow) during the predefined
The Srxlev value of the evaluated neighboring cell is always greater than the threshold used in reselection to lower-priority cells (ThreshXLow)
during the predefined cell reselection time cell reselection time.
The UE has camped on the serving cell for more than 1 second
Low Priority Cell Reselection Criteria
36

[5] CONNECTED MODE
Mobility Management
Redirection:
Redirection is the substitute solution for handover ,used in the following scenario:
UE or network doesn’t support handover.
There is no Neighbor relation.
When redirection is triggered, eNB sends the UE an “RRC Connection Release”
message which contains information about a neighboring frequency in the LTE
system or in another RAT system.
Handover :
Handover process consists of three phases:
Handover measurement, handover decision, and handover execution.
A blind handover does not require handover measurement.
In the handover measurement phase, the eNB uses the RRC Connection
Reconfiguration message to deliver the measurement configuration to the UE and
waits for a measurement report from the UE.
In the handover decision phase, the eNB checks the measurement results reported
by the UE and determines whether to initiate a handover.
In the handover execution phase, the eNB controls the procedure of UE handover
to the target cell based on the decision, to perform the handover.
37

[5] CONNECTED MODE
Handover Trigger Scenarios
Handover Type Measurement Trigger
Coverage
based
Intra-frequency The measurement configuration is performed when the UE establishes a radio bearer.
The UE performs intra-frequency measurements by default.
Inter-frequency
Inter-RAT
The eNB delivers the measurement configuration to the UE when the signal quality in
the serving cell is lower than the associated threshold.
Load based Inter-frequency
Inter-RAT
The measurements are triggered by the Mobility Load Balancing (MLB) algorithm.
Frequency-
priority-based
Inter-frequency The measurements are triggered by A1 event
Service based Inter-RAT
Inter-frequency
The eNB triggers the measurements after it finds that only the voice service is running
on the UE.
UL service
quality Based
Inter-RAT
Inter-frequency
The eNB triggers the measurement after it detects UL power insufficient at the UE
Distance based Inter – frequency
Inter -RAT
The measurements are triggered by distance if it is more than the specific threshold
38

[5] CONNECTED MODE
Measurement Control Information  When a UE establishes a radio bearer, the eNB delivers the intra-frequency
measurement configuration to the UE through an RRC Connection
Reconfiguration message by default.
 When measurement gaps need to be set up, the eNB delivers the
inter-frequency and/or inter-RAT measurement configuration to the UE.
After that, the UE performs gap-assisted inter-frequency and/or inter-RAT
measurements. Inter-frequency and inter-RAT measurements can use the
same gap pattern, but the eNB is able to differentiate between the gap
configurations for inter-frequency and inter-RAT measurements.
Measurement Object – Frequency
Parameters Description
DlEarfcn Indicates the DL EARFCN of the inter-frequency E-UTRAN cell
MeasBandWidth Indicates the measurement bandwidth for inter/intra-frequency neighboring cells
QoffsetFreq Indicates the frequency offset of the inter-frequency neighboring cell
neighCellConfig Indicate whether all the neighbor have the same configuration or not
PresenceAntennaPort1 Indicates whether all of the inter-frequency neighboring cells are configured with the
double-TX antenna.
High priority neighbor
cell list (Optional)
If we configure some specific neighbors as high measurement priority, then eNB will
deliver these cells information as well.
39

[5] CONNECTED MODE
Page 40
Event Triggered Report
Events Threshold Action
A1 Signal quality in the serving cell is higher than a specified
threshold
The eNB stops inter-frequency or inter-
RAT measurements.
A2 Signal quality in the serving cell is lower than a specified
threshold
The eNB starts inter-frequency or inter-
RAT measurements
A3 Signal quality in at least one intra-frequency/inter-
frequency neighboring cell is higher than that in the
serving cell
Source eNB sends an intra-
frequency/inter-frequency handover
request.
A4 Signal quality is higher than a specified threshold in at
least one inter-frequency neighboring cell
Source eNB sends an inter-frequency
handover request.
A5 A2 + A4 (New events in eRAN3.0) Source eNB sends an inter-frequency
handover request.
B1 Signal quality is higher than a specified threshold in at
least one inter-RAT neighboring cell
source eNB sends an inter-RAT handover
request.
B2 A2 + B1 source eNB sends an inter-RAT handover
request. 40

[5] CONNECTED MODE
eNB Neighbor Management  A neighboring relation is a relation between the serving cell and each
candidate cell involved in a handover. Neighboring relation
management covers the following aspects:
Whether to allow automatic removal of a neighboring relation
by ANR or not
Whether to allow handovers of UEs between two cells or not
Whether to allow handovers over an X2 interface or not
Neighboring relations are planned in the network design stage. They
can be automatically adjusted by ANR.
Intra-frequency neighboring cell
An intra-frequency neighboring cell is a neighboring cell whose
DL E-UTRA Absolute Radio Frequency Channel Number (EARFCN)
is the same as the DL EARFCN of the serving cell. An E-UTRAN
cell can be configured with a maximum of 32 intra-frequency
neighboring cells.
Inter-frequency neighboring cell
An inter-frequency neighboring cell is a neighboring cell whose
DL EARFCN is different from the DL EARFCN of the serving cell.
An E-UTRAN cell can be configured with a maximum of 64 inter-
frequency neighboring cells, which can be located on a
maximum of 8 neighboring E-UTRAN frequencies.
TDD cells can also be configured as inter-frequency neighboring
cells of FDD cells. Huawei eNB supports interoperability
between LTE FDD and LTE TDD. 41

[5] CONNECTED MODE
Intra-frequency Handover Procedure
Measurement Triggers
(Coverage Based)
Measurement Configuration
message
Measurement RSRP/RSRQ
Event A3
Black cell list
If criteria is matched, UE
sends measurement report.
eNB Performs Handover
Admission Procedure
Signaling Procedure
Execution
Retry Mechanism (attempt
to next target cell in
measurement report list)
eNB Makes Decision
Event Triggered Periodical
Reporting
Intra-eNB cell has higher
priority to reduce Inter-eNB
signaling or data
forwarding.
Via S1 or X2
Event A3 Measurement Report
Intra-frequency handover is triggered by event A3,
which is reported in event-triggered periodical
reporting mode.
 Enter condition:
Mn + Ofn + Ocn – Hys > Ms + Ofs + Ocs + A3Off
 Leave condition:
Mn + Ofn + Ocn + Hys < Ms + Ofs + Ocs + A3Off
42

[5] CONNECTED MODE
Handover Decision – Target Decision
After get candidate list, eNB will rank the list with the following priority:
The best RSRP/RSRQ neighbor cell
Intra-eNB neighbor cell if reported result is the same
Inter-eNdoeB neighbor cell with X2 interface if reported result is the same.
The eNB then sends a handover request to the target cell at the top of the candidate cell
list. If the handover request fails, the eNB sends the handover request to the next target cell.
 UE and the eNB exchange signaling over the radio interface according to 3GPP TS 36.331.
 During an inter-eNB handover, the source eNB and the target eNB exchange signaling and data
through X2/S1 adaptation.
The LTE system uses hard handover, that is, only one radio link is connected to a UE at a time.
Therefore, to prevent user data loss at the eNB during the handover, data forwarding is performed to
ensure eNB data integrity.
In the case of an intra-MME inter-eNB handover, the source eNB checks whether the X2 interface is
available between the source and target eNBs or not and then automatically selects a path for the
handover as follows:
If the X2 interface is available, the handover request is sent over the X2 interface.
If the X2 interface is unavailable, the handover request is sent over the S1 interface.
Handover Execution – S1/X2 Adaption
43

[5] CONNECTED MODE
Inter-frequency Handover Procedure
 Measurement based handover: HO must be trigged by inter-frequency measurement report.
 Blind handover: Skip inter-frequency measurement, directly execute HO based on priority
configuration .
44

[5] CONNECTED MODE
Inter-frequency Handover Procedure
(Coverage Based)
UE Reporting Event A2 to
trigger inter-frequency
measurement based on
coverage Single or both of
RSRP/RSRQ monitored to
trigger IF measurement
Stop measuring when
Event A1 is met
Measurement
GAP-Assisted
Measurement
Reporting A3/A4/A5
Admission Procedure
Execution
Retry Mechanism (attempt
to next target cell in
measurement report list) If
Admission or Handover
Failure
eNB Makes Decision
Reporting
Single or both of RSRP /
RSRQ considered to make
decision
Via S1 or X2
45

[5] CONNECTED MODE
Coverage Based Measurement Trigger
Enter condition: Ms + Hys < Specific A2
Threshold
Leave condition: Ms – Hys > Specific A2
Threshold
LTE
GSM/UMTS Coverage
Intra-LTE Inter-RAT
According to radio link condition (LTE: RSRP/RSRQ)
Moves to neighbor
LTE cell
Moves out of LTE
coverage
Ms: The measurement result of the serving cell
Hys: The hysteresis for event A2
Thresh: The threshold for event A2, it can be
defined separately with RSRP or RSRQ
Coverage Based Measurement Stop
Enter condition: Ms – Hys >
Specific A1 Threshold
Leave condition: Ms + Hys >
Specific A1 Threshold
46

[5] CONNECTED MODE
Inter-frequency Handover Report Event
For coverage based scenario:
A3/A4/A5 can be used to trigger inter-frequency HO, decided by InterFreqHoEventType parameter
For the other scenario:
Only A4 event can be used
A5 event is recommend to prevent ping-pong handover
Event A3 in inter-frequency handovers uses the same set of parameters with that in intra-frequency handovers, except the offset and
frequency-specific offset.
Enter condition: Mn + Ofn + Ocn – Hys > Ms + Ofs + Ocs + A3Off
Leave condition: Mn + Ofn + Ocn + Hys < Ms + Ofs + Ocs + A3Off
A4 enter condition: Mn + Ofn + Ocn – Hys > Specific A4 Threshold
A4 leave condition: Mn + Ofn + Ocn + Hys < Specific A4 Threshold
A5 enter condition: Mn + Ofn + Ocn – Hys > Specific A4 Threshold and Ms + Ofs + Ocs + Hys
< Specific A2 Threshold
A5 leave condition: Mn + Ofn + Ocn – Hys < Specific A4 Threshold or Ms + Ofs + Ocs + Hys >
Specific A1Threshold
Event A4/A5
47

[5] CONNECTED MODE
Inter-RAT Handover Procedure
(Coverage Based)
UE Reporting Event A2 to
trigger inter-frequency
measurement based on
coverage
Single or both of RSRP / RSRQ
monitored to trigger IF
measurement
Stop measuring when Event
A1 is met
Measurement
GAP-Assisted Measurement
Reporting B1/B2 (for U/G/C)
Admission Procedure
Signaling Procedure Execution
Retry Mechanism (attempt to
next target cell in measurement
report list) if admission or
handover failure
eNB Makes Decision
Reporting
To be considered to make
decision:
RSCP or Ec/No for UMTS
Rx_Level for GSM
Pilot Strength for CDMA2000
48

System Object Parameters
UMTS
RSCP InterRATHoUtranB1ThdRSCP for coverage-based handovers
LdSvBasedHoUtranB1ThdRSCP for load and service-based handovers
Ec/No InterRATHoUtranB1ThdEcN0 for coverage-based handovers
LdSvBasedHoUtranB1ThdECN0 for load- and service-based handovers
GERAN RSSI
InterRATHoGeranB1Thd for coverage-based handovers
LdSvBasedHoGeranB1Thd for load and service-based handovers
cdma2000 Pilot Strength InterRATHoCDMAB1ThdPS for coverage-based handovers
Measurement Object
[5] CONNECTED MODE
Measurement Trigger
Coverage based:
The same as inter-frequency handover, use event A2/A1.
Enhanced A1A2 threshold for UTRAN and GERAN.
Load based/Distance based/UL quality based
The same as inter-frequency handover
Service based
In a service-based handover, the eNB hands over a UE to another system based on the type of the service running on the
InterRatHoStateUE.
The applicability of handover is set through the parameter, whose values are MUST_HO, NO_HO, and PERMIT_HO.
49

[5] CONNECTED MODE
Inter-RAT Handover Event
For coverage based scenario:
B1 and B2 can be used and decided by InterRatHoEventType
For the other scenario:
Only B1 is supported
B1 enter condition: Mn + Ofn – Hys > Specific B1 Threshold
B1 leave condition: Mn + Ofn + Hys < Specific B1 Threshold
B2 enter condition: Mn + Ofn – Hys > Specific B1 Threshold and
Ms + Ofs + Ocs + Hys < Specific A2 Threshold
B2 leave condition: Mn + Ofn – Hys < Specific B1 Threshold or
Ms + Ofs + Ocs + Hys > Specific A2 Threshold
Mn: The measurement result of the neighboring cell
Ofn: The frequency-specific offset for the frequency of the
neighboring cell
Hys: The hysteresis for event B1. The hysteresis values for inter-
RAT handovers to UTRAN, GERAN, and CDMA2000
50

[5] CONNECTED MODE
LTE PS 2G(GPRS)/3G PS
PS handover
LTE VOIP 2G/3G CS
SRVCC
LTE PS
CCO/NACC
GSM PS
Handover Execution
51

RF OPTIMISATION PROCESS
Pre-Launch
After a network is built and before is launched on air, it is
necessary to perform the pre-launch optimization where the
common process is to divide the network in groups of sites
(clusters) and optimize these clusters so agreed KPIs are achieved.
Changes during pre-launch optimization are mainly physical (e.g.
antenna tilts and azimuths) although they may include also some
parameter changes (e.g. Tx Power) with the scope of optimizing the
coverage and the quality of the network.
As there is no/very little traffic on the network, counters don’t
provide statistically reliable information. Therefore, the main
optimization method during the pre-launch optimization to achieve
certain field KPIs is drive testing.
Post-Launch
After the launch, networks are ‘alive’, always changing (e.g. traffic
conditions, addition of new sites, new software upgrades) so
optimization is still needed to keep the high level of performance
defined by the KPIs. Since there is traffic on the network, counter
information is reliable and it is possible to have a centralized view of
how the whole network is performing.
RF Optimization is necessary so the network performance satisfies certain thresholds or targets for Key Performance
Indicators (KPIs).
RF Optimization Flowchart
53

55
FIELD MEASUREMENT PARAMETERS
3GPP is defining following measurements:
– RSRP (Reference Signal Received Power)
– RSRQ (Reference Signal Received Quality)
Scanners and terminals are typically measuring following RF quantities:
– RSRP
– RSRQ
– RSSI, Wideband channel power
– P-SCH, S-SCH power
– RS SINR, P-SCH/S-SCH SINR
Understanding of different measurement quantities is very important for field performance analysis.

56
RSRP (Reference Signal Received Power)
RSRP, 3GPP definition
 RSRP is the average received power of a single RS resource element.
 UE measures the power of multiple resource elements used to transfer
the reference signal but then takes an average of them rather than
summing them.
 Reporting range -44…-140 dBm
 Channel estimation in LTE is based on RS,Reference Signals (like CPICH functionality in WCDMA).
 Reference Signals (RS) position in time domain is fixed (0 and 4 for Type 1 Frame) whereas in frequency domain it depends on the
PCI (Physical Cell ID).
 In case more than one antenna is used (e.g. MIMO) the Resource elements allocated to reference signals on one antenna are DTX
on the other antennas Reference signals are modulated to identify the cell to which they belong.

57
RSSI (Received Signal Strength Indication)
RSSI, 3GPP definition
 RSSI not reported to eNodeB by UE
– Can be computed from RSRQ and RSRP that are reported by UE
 RSSI measures all power within the measurement bandwidth
– Measured over those OFDM symbols that contain RS
– Measurement bandwidth RRC-signalled to UE
RSSI = wideband power= noise + serving cell power + interference power
 Without noise and interference, 100% DL PRB activity: RSSI=12*N*RSRP
– RSRP is the received power of 1 RE (3GPP definition) average of power levels received across all Reference Signal
symbols within the considered measurement frequency bandwidth
– RSSI is measured over the entire bandwidth
– N: number of RBs across the RSSI is measured and depends on the BW
 Based on the above, under full load and high SNR:
RSRP (dBm)= RSSI (dBm) -10*log (12*N)

58
RSRQ (Reference Signal Received Quality)
RSRQ = N x RSRP / RSSI
– N is the number of resource blocks over which the RSSI is
measured, typically equal to system bandwidth
– RSSI is pure wide band power measurement, including intracell
power, interference and noise
 RSRQ reporting range -3…-19.5dB
RSSI = noise + serving cell power + interference power during RS symbol
RSRQ depends on serving cell power and the number of Tx antennas
Impact of serving cell power to RSRQ:
Example for noise limited case (no interference):
 If all resource elements are active and are transmitted with equal power then
RSRQ = N / 12N = -10.8 dB for 1Tx
RSRQ = N / 20N = -13 dB for 2Tx, taking DTX into account (because RSRP is measured over 1 resource element and RSSI per resource
block is measured over 12 resource elements). Remember that RSSI is only measured at those symbol times during which RS REs are
transmitted.
When there is no traffic, and assuming only the reference symbols are transmitted (there are 2 of them within the same symbol
of a resource block) from a single Tx antenna then the RSSI is generated by only the 2 reference symbols so the
result becomes;
RSRQ = N / 2N = -3 dB for 1Tx
RSRQ = -6dB for 2Tx.

SINR is the reference value used in the system simulation and to measure the signal quality of LTE
 SINR can be defined:
1. Wide band SINR
2. SINR for a specific subcarriers (or for a specific resource elements)
 SINR = S/(I+N), all measured over the same bandwidth
 Most drive test UEs and scanners support SINR or SNR measurement
 Example: LG supports RS SNR measurement
 Example: Samsung BT-3710 measures CINR from RS
RSRQ to SINR mapping
 RSRQ depends on own cell traffic load, but SINR
doesn’t depend on own cell load.
– Used Resource Elements per Resource Block (RE/RB)
in serving cell is an input parameter for RSRQ -> SINR
mapping
– Assumption: RSRP doesn’t contain noise power
Equation used:
– x=RE/RB
59
SINR (Signal to Interference plus Noise Ratio)

• CPICH for pilot
• RSCP
• Ec/Io
GSM
• BCCH for pilot
• Rx lev
• C/I
• RS for pilot
• RSRP
• RS SINR
UMTS LTE
GUL Signals Used for Coverage Evaluation
60

UMTS VS LTE RSRP & RS SINR
RSCP
Ec/Io
CPICH
Load: power
/interference
Interference:
own &
adjacent cell
RSRP
RS SINR
Interference:
adjacent cell
Load: RB
Reference
signal
Coverage
Evaluation
UMTS LTE
61

Same Band RxLev, RSRP and RSCP Comparison
Items GSM UMTS LTE
(e)NodeB power per Tx (dBm) 43 43 43
Bandwidth (MHz) 0.2 5 20
Number of RB N/A N/A 100
BCCH Power/ CPICH power /RS
power per RE (dBm) 43 33 15.2
CL (dB) 120 120 120
Rx Lev/RSCP/RSRP (dBm) -77 -87 -104.8
RSRP is the received signal strength
over 15KHz bandwidth while
bandwidth of RSCP is 5MHz.
RS Power is 17.8 dB smaller than
CPICH Power (LTE =20MHz)
RSRP of LTE is much smaller than RSCP of UMTS under same radio environment
62

RSRP Drive Test Results
Conditions
• 2.6GHz, 20MHz bandwidth
• 2*20W power configuration
0%
5%
10%
15%
20%
25%
30%
35%
-70≤RSRP -80≤RSRP≤-70 -90≤RSRP≤-80 -105≤RSRP≤-90 RSRP≤-105
8.60%
29.90%
34.50%
25.80%
1.20%
About 27% RSRP is
smaller than -90dBm
Drive test results also proves RSRP smaller than RSCP
63

64
RF OPTIMISATION
Performance in LTE is strongly impacted by interference. This is typical to any cellular technology working with frequency re-use 1.
Thus, SINR distribution is the main throughput limiting factor. Any interference reduction is reflected by an increase in cell range and
user throughput.
Antenna tilts and azimuths (to certain extent) are strong primary RF shaping factors.
Basic RF planning is important
 Clear cell dominance areas
 Avoid sites shooting over large areas with other cells

65
RF OPTIMISATION
RSRP Plot Best Server PCI Plot
Based on the RSRP
SINR and the Best
Server PCI plots
identify the problem
areas.
SINR Plot
Swapped sectors case
example of swapped
feeders between
sectors 2 (light green)
and 3 (light blue) in site
36431.

66
RF OPTIMISATION – Coverage Problem
Weak Coverage
No dominant cell

67
RF OPTIMISATION – Poor SINR
Improving performance by blocking excess cells
Overall SINR is improved due to reduction of inter-cell
interference.
Locations with improved SINR are visible on the map.
Improvement in throughput is even more significant.

68
RF OPTIMISATION – Cross Sector
Symptom
Analysis of the data of a clutter shows that the cell PCI coverage of
eNB 262 is unreasonable, as shown in the upper picture. This lead to
access failure and call drop during drive test.
Analysis
An analysis shows tht cells 0 (9), 1(10) and 2(11) have been
connected incorrectly to cells 1,2, and 0 in the planning (cross sector).
Solution:
Fix cross sector and drive test verify the result.
BEFORE
AFTER

69
RF OPTIMISATION – Solutions

Lte principle

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