C 6 6270 Optimization 002 KH

7/29/2019 C 6 6270 Optimization 002 KH

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TA-TC 6270 /Version 01/Chap. 05 Optimization

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2SWLPL]LQJ DQGH[SDQGLQJ 875$1Purpose

The main objectives of WCDMA RAN optimization are to enable better availability of network services(coverage criteria) and to provide a pre-defined service quality and performance (quality of service,QoS, criteria).

Optimization based on coverage criteria:

-Coverage for different data rate services and maximum loading based on traffic forecasts andmargins set for load variation. The cell breathing effect allows the cell size to vary with the load: thesmaller the load, the greater the coverage and vice versa.

- Pilot channel coverage

-Soft handover areas and probabilities The coverage criteria is ensured by pre-planning as well ascontinuous measuring and monitoring of a roll-out and running network.

Further information: the objective of optimizing pilot power is to ensure that the pilot Ec/I0requirement is achieved at the cell edge while minimizing the areas of overlapping cells. The pilot

power itself is set in the database per cell. The common downlink pilot channel is used by the mobilestations for synchronization and channel estimation. Assigning excessive quantities of pilot powerreduces the system capacity, less power is available for traffic channels.


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Ec/No = RSCP/RSSI

3GPP allows 3 measurement quantiities

to be used as basis for reports:

-CPICH ECNO

-CPICH RSCP

-(Pathloss)

UTRACarrier

RSSI

P-CPICHRSCP

Signal with primaryscrambling code ofdefined cell

Signals of other cellstime

frequency

Rx power

RSSI = Received Signal Strength Indicator RSCP = Received Signal Code Power

ECNO


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f

The Common Pilot Channel is one of the most important UMTS channels and is used for: synchronisation with the cell scrambling code, cell selection/reselection, handover decision,

and as a measurement benchmark.

f Tuning of the CPICH power has a big impact on coverage/capacity optimization. Hightransmission power of CPICH reduces the DL capacity, increases DL interferences but alsoincreases the service coverage. Low power may cause unreliable handovers, high call droprate or longer synchronisation process, but from the other hand saves the DL resources.

f The quality of the CPICH can be measured as: RSCP CPICH or CPICH Ec/Io.

f RSCP CPICH is the absolute measure of the code power in the whole 3.84MHz bandwidth

f Ec/Io is the relative

measure of the signal quality.

Reporting ranges

for CPICH Ec/I0:

-24 ...0 dB

(TS 25.133)0 dB CPICH_Ec/N0CPICH_Ec/N0_00

...

-23.5 dB CPICH_Ec/N0 < 23.0 dBCPICH_Ec/N0_00

-24 dB CPICH_Ec/N0 < 23.5 dBCPICH_Ec/N0_00-CPICH_Ec/N0 < -24 dBCPICH_Ec/N0_00

Measured valueReported value


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Increase of pilot signal power:

Increased DL interference,

Increase of soft handovers

Decrease of DL capacity

overlappingarea

for cells 1-2coverage hole

between cells 1a & 2

Cell 1

Cell 1a

Cell 2

Decrease of pilot signal power:

Decrease of coverage area,

Less reliable handovers

Longer synchronization process


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During network launch pay special attention to:f Interference and noise control (pilot pollution). This exists if received code power is high but

Ec/I0 is very low. Pilot pollution can be optimized by, for example, reducing the signal of theneighbouring cells and by optimising antennas tilts for the neighbouring cells.

f Weak coverage. Low mobile receiver power leads to the degradation of service quality dueto, for example, fading, low Ec/I0, poor FER and it can be improved by adding a site, a betterantenna, or adjusting parameters.

f Call functionality problems, for example, call setup fail or call drop

f System performance degradations due to unbalanced control channel, for example, capacitydegradation.

Reporting ranges

for CPICH RSCP:

-115 ...-25 dBm

(TS 25.133)

-25 dBm CPICH_RSCPCPICH_RSCP_LEV_91

...

-114 dBm CPICH_RSCP < -113 dBmCPICH_RSCP_LEV_02

-115 dBm CPICH_RSCP < -114 dBmCPICH_RSCP_LEV_01

CPICH_RSCP < -115 dBmCPICH_RSCP_LEV_00

Measured valueReported value


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0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1

load

TCP[dBm]

Congestion Control

TCP total

P max

load max


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Optimization based QoS criteria (KPIs):

-Total data throughput in a cell

- End user data throughput (application throughput)

- Delays

- Call setup success rates for different services

- Call drop rates

- Handover Performance

Define network quality

and performance targets!

Check the alarmsituation.

Evaluate the statistics. Compare with performance targets

High airinterface load.

Resource utilisationproblems.

Air interfaceproblems.

Check if there areknown UE problems

Troubleshouting needed

OK

NOK

OK

NOK

....

Make sure what the problem is and what the consequences of the corrective actions are.


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Problems can be solved either with hardware changes or parameter optimization.Examples of different solutions are:

- adding or deleting radio network objects

- modifying adjacencies

Modifying adjacencies is necessary when BTSs are added to or deleted from the network.

- RNC split (3G rehosting)

RNC split means reconfiguring and expanding the network by rehosting a BTS site to another RNCor by adding a new BTS under an RNC using an existing site as a reference site.

- modifying parameters

Consider whether modifications will affect the services. If they do, plan a date and time for the taskand inform the organisation about the plans. If an element has to be locked for modification, itcannot transmit traffic. By planning and preparing for service loss you can minimize the

unavailability of services.

Adding a site later will affect neighbouring sites and a re-optimisation in the area is necessary.


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Parameters allow to optimize the usage of radio network and to fully utilize the planned coverageand capacity. There are parameters related to radio resource management and by tuning those thecapacity can be used best without compromising the quality of services. Radio resourcemanagement is responsible for efficient utilization of the air interface resources and is needed tomaximize the radio performance. They allow to

- guarantee the quality of service: block error ratio (BLER), bit error ratio (BER), and delay

- maintain the planned coverage for each service

- ensure the planned capacity with low blocking

- optimize the use of capacity

- make the best use out of existing hardware

Planning radio network is an iterative process and parameters are planned together with coverageand capacity planning. The parameters offer an initial configuration of the network and the

parameters could be set in the beginning to offer 'loose' limits and admission to all users. Theparameters could be improved later during network optimization to manage the capacity-qualitytrade-off. Parameters are defined in the data-base of the RNC (NodeB?).

Change only one parameter at a time so that you can see what kind of influence thatparameter has on the network.


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0...31

RNC

Radio Bearer

Control

BRA Buffer

UtilizationHSDPA

Inter System

Handover Control

NodeB

Outer Loop

Power Control

Adjacent

RNC

Dedicated Measurement

Information

Intra Frequency

Handover Control

Intrer Frequency

Handover Control

UTRAN Cell

Adjacent

GSM Cel lInfo

Adjacent

UTRAN Cell Info

0...32Dl Common

Channel

UL Common

Channel

Admission Control

Congestion Control

Reselection ControlGeographical Data

The number of cells and Node B depends on the vendor, the parameters may be found in different objects,there may be additional parameter objects.


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When the UE is switched on, it looks for a public land mobile network (PLMN) using a certain radioaccess technology.

In the selected PLMN a suitable cell is selected and if this new cell is not in a registered area,location registration is performed via RNC to the core network. The overall process is divided intothree sub-processes:

PLMN selection and reselection to search for an available mobile network.

The selection of the PLMN could be either automatically (list of PLMN to be selected in priorityorder) or manually (the mobile station indicates available PLMN to the user).

In the home PLMN, the MCC (Mobile Country Code) and MNC (Mobile Network Code) of the PLMNidentity match the MCC and MNC of the IMSI (International Mobile Subscriber Identity) stored onthe USIM (UMTS Subscriber Identity Module). If the UE loses its present PLMN coverage, a newavailable PLMN is selected automatically or manually. If necessary, the UE will do reselection bysearching a suitable cell on a different PLMN.

Cell selection and reselection to search for a suitable cell belonging to the selected PLMN.

Location registration to register the UEs presence in a registration area.


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PLMN Selectionand Reselection

Cell selectionand

Reselection

Location registration

Power on

PLMNPLMNselected

PLMNavailable

Registration

IMSI format

MCC3 digits

MNC2~3 digits

MSIN(Mobile Subscriber Identity Number)

Maximum 10 digits

USIM card

CN

RegistrationResponse


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6HUYLFH/HYHOVThe network provides different levels of service to a UE in either Idle mode or Connected mode. Threelevels of services are defined:

LIMITED SERVICE: Acceptable cell: UE may camp to obtain limited service like emergency call. Theminimum set of requirements for initiating an emergency call in a UTRAN network are:

The cell is not barred.

The cell selection criteria are fulfilled.

NORMAL SERVICE: for public use on a suitable cell. Suitable cell: UE may camp on to obtain normalservice. Such a cell shall fulfill all the following requirements:

The cell is part of the selected PLMN

The cell is not barred

The cell is not part of a forbidden registration area

The cell selection criteria are fulfilled

OPERATOR SERVICE: FOR OPERATORS ONLY ON A RESERVED CELL.

Reserved cell: When the cell status "reserved for operator use" is indicated and the Access Class of theUE is 11 or 15 the UE may select/re-select this cell if in Home PLMN.

Barred cell: When cell status "barred" is indicated the UE is not permitted to select/re-select this cell, noteven for limited services. UE shall perform a periodic check of the situation. Alternatively the UE can getservice by camping on another cell on the same frequency. This is done by setting the "Intra-frequencycell re-selection indicator" to "allowed". Also in this case a too frequent evaluation of the barred cell maybe avoided excluding the restricted cell from the neighboring cell list.


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Candidate List: :- Cell Information:Carrier frequency,Scrambling code,etc

- Neighboring cells:Cell 1,cell 3,cell 4, Cell 4

Cell 1

Cell 2

Cell 4

Cell 3

System information:-PLMN identity

-Cell information-Neighboring cells


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Idle mode cell selection andreselection

If the UE is unable to find any suitable cell in the selected PLMN, the UE enters to "any cellselection" state.

1. Camped normally state: UE obtains normal service and performs the following tasks:

Select and monitor the PICH and PCH of the cell.

Performs system information monitoring.

Perform necessary measurements for the cell reselection evaluation procedure.

Execute the cell reselection evaluation procedure.

If after cell reselection evaluation process a better cell is found, the cell reselection is performed. Ifno suitable cell is found, the UE enters to next state any cell selection.

2. Any cell selection: UE searches an acceptable cell of any PLMN to camp on. If an acceptable

cell is found, the UE reports to NAS and camp on this cell obtaining limited service. And UE entersto camped on any cell state. If the UE can not find any acceptable cell, it stays in this state.

3. Camped on any cell state: UE obtains limited service and periodically searches for a suitablecell in the selected PLMN. If a suitable cell is found the state changes to Camped normally.

The next figures show the initial cell selection and process for idle mode cell selection andreselection.


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Idle mode cell selection andreselection

No USIM

USIM inserted

Camped on any cell

NoYes

No suitablecell found

Storedinformation



Suitable cellfound

Suitable cellfound

Acceptable

cell found

Suitable cellfound

No Acceptablecell found

Connectedmode

Connectedmode

(EC only)

Suitablecell foundtrigger

Acceptablecell found

trigger

Stored information

Cell Selection

Cell Reselection

evaluation

Cell Reselection

evaluation

Initial

Cell Selection

New PLMN Selection

Camped normally

Any cell selection


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The cell search is carried out in three steps:

Step 1 (Slot synchronization): The mobile station uses the 256 chip primary synchronization codeto acquire slot synchronization to a cell. The UE distinguishes the SCH channel from different cellsby the offset timing.

Step 2 (Frame synchronization/code group identification): Based on the peaks detected for theprimary synchronization code, the mobile station seeks the largest peak from the secondary SCHcode word in order to find the frame synchronization and the code group identification. There are 64possibilities for the secondary synchronization code word.

Step 3 (Scrambling code identification): The terminal seeks the primary scrambling codes thatbelongs to the particular code group. Each code group consists of eight primary scrambling codes.

During the cell searching the UE must be synchronized between adjacent cells of the same NodeBto avoid overlap of SCH channels. SCH channel overlap introduces interference and increases thecell search and synchronization time. For cell synchronization an offset timing parameter is used

with a range between 0 to 2304 chips (0.6ms). This offset timing range is at 256 chip steps(0.06ms). The SCH transmit power level is set by radio parameters as an offset respect to theCPICH transmit power level. It is important to set the value correctly to ensure all the downlinkcommon control channels have a common footprint.


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SCH

1

Sector 2Sector 1

Sector 3

SCH1 SCH2 SCH3

Offset timing=256 Offset timing=512

P(t)

t

CPICH timing offset of the cell

S-SCH power offset

SCH3

SCH2


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The cell selection criterion S is a pre-condition for suitable cells. The conditions for UTRAN FDDand GSM cells are described below.

The UE measures the CPICH Ec/Io and CPICH RSCP level of the serving cell and evaluates thecell selection criterion S for the serving cell at least every DRX cycle.

CS DRX Cycle length = 6, i.e. 26 frames = 640 ms

PS DRX Cycle length = 6, i.e. 26 frames = 640 ms

If the UE has evaluated in Nserv (depends on the DRX cycle length) consecutive DRX cycles thatthe serving cell does not fulfill the cell selection criterion S, the UE initiates the measurements of allneighbor cells indicated in the measurement control system information.

Squal Cell Selection quality value (dB); Applicable only for FDD cells.

Srxlev Cell Selection RX level value (dB)

.


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Suitable cells:

FDD cells: Srxlev > 0 AND Squal > 0GSM cells: Srxlev > 0

Squal => CPICH EC/N0

Srxlev => CPICH RSCP

*) Pcompensation = max (UE_TXPWR_MAX_RACH - P_MAX, 0)

Squal = Qqualmeas QqualminSrxlev = Qrxlevmeas - Qrxlevmin Pcompensation *)

Qqualmeas: Measured cell quality value. The quality of the received signal expressed in CPICHEc/N0 (dB) for FDD cells. CPICH Ec/N0 shall be averaged. Applicable only for FDD cells.

Qrxlevmeas: Measured cell RX level value. This is received signal, CPICH RSCP for FDD cells (dBm)Qqualmin Minimum required quality level in the cell (dB). Applicable only for FDD cells.

Qqualmin (-24, -23 .. 0) dB Specifies the minimum required quality level in the neighbour cell in dB.

Qrxlevmin: (-115, -113 .. 25) dBm Minimum required RX level in the neighbour cell (dBm)

UE_TXPWR_MAX_RACH: (-50, -49 .. 33) dBm Specifies maximum allowed uplink transmissionpower on the RACH in the cell.

P_MAX: Maximum RF output power of the UE (dBm)

Set in the Data Base perCell and broadcast in the

cell the UE camps on.


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The cell reselection evaluation process depends on whether Hierarchical Cell Structure (HCS) isused or not. In order to perform cell reselection UE measures and ranks the neighbor cells. Foreach type of neighbor cells (Intra-Frequency; Inter-Frequency; Inter-RAT, i.e. GSM) thresholds aredefinable. Measurements of neighbor cells will be triggered if these thresholds are reached.

Measurement of neighbor cells:

Intra-Frequency: Squal


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Ranking (cell reselection evaluation) is performed according to the UE internal triggers or if theinformation on the BCCH used for the cell reselection evaluation procedure has been changed.

(Re-) Selected cell is a suitable cell (fulfills the S criterion) and is the best ranked cell (has thehighest R). The UE shall however reselect the new cell, only if the following conditions are met:

the new cell is better ranked than the serving cell during a time interval Treselections.

more than 1 second has elapsed since the UE has camped on the current serving cell.

The cell-ranking criterion R is defined as shown below:

Note,

s indicates the serving cell,

n indicates the neighbour cell.

Ranking of cells:

Rs = Qmeas,s + QhystS

Rn = Qmeas,n Qoffsets,nRe-selected cell: Suitable (S Criterion)

Best Rank(Highest R)


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Qmeas,s / Q meas,n = CPICH RSCP / RxLev Qhyst1ss,n & Qoffset1ss,nQmeas,s / Q meas,n = CPICH Ec/No Qhyst2ss,n & Qoffset2ss,n

FDD: = rscp cell rslc qhyst1s & qoffset1= ecno cell rslc qhyst2s & qoffset2

Treselections ( 0, 1 .. 31) s Cell selection timer [sec]

Cell_selection_and_reselection_quality_measure (ECNO, RSCP) Choice of measurement fromCPICH Energy per PN chip to Noise Ratio (Ec/N0) or CPICH Received Signal Code Power (RSCP),to be used for quality measurement.

Qhyst1-s (0, 2 .. 40) dB The hysteresis value for GSM cells and for FDD cells in case the qualitymeasure for cell selection and re-selection is set to CPICH RSCP.

Qhyst2-s (0, 2 .. 40) dB The hysteresis value used for FDD cells if the quality measure for cellselection and re-selection is set to CPICH Ec/No.

Qrxlevmin (-115, -113 .. 25) dBm Specifies minimum required RX level in the cell

Inter RAT measurement indicator: (true, false) Specifies whether UE starts inter RAT cell

reselection

Inter FDD measurement indicator: (true, false) Specifies whether UE starts inter FDD cellreselection

Qoffset1(s,n) (-50, -49 .. 50) dB Specifies offset between two cells in case quality measurement forcell selection and re-selection is set to CPICH Received Signal Code Power (RSCP).

Qoffset2(s,n) (-50, -49 .. 50) dB Specifies offset (minimum RX level in cell in dBm) between twocells in case quality measurement for cell selection and re-selection is set to CPICH Ec/No.

Defined perCell

Defined peradjacent Cell


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Neighbour cell

Qoffset(s,n)

Qqualmeasured

time

Qhyst (s)

Qqualmin ofneighbour

and serving

Serving cell of UE

Neighbourwould be good

enough

Sintrasearch

UE startsmeasurements UE starts

TreselectionTimer

TreselectionTimer expiry

Reselection

Treselections


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Hierarchical cell structure uses macro, micro and pico network layers. Mobiles are able toconnect any of these layers at the same geographical location.Next figure shows anexample of the hierarchical cell structure. Layers arerepresented by numbers. In this examplenumber 2 is the layer with the highest priority (i.e. normally the smallest cell). The FDD macrocell provides the wide area coverage and is also used for high-speed mobiles. The microcells are used at street level for outdoor coverage to provide extra capacity where macrocells could not cope. The pico cell would be deployed mainly indoors (office, subway stations,underground garagesetc where is demand medium or high traffic density Theimplementation of hierarchical cell structure provides different benefits to the customer

Flexibility in frequency planning moving to different frequency layers;

Easy introduction of load balancing functions;

Increase the network capacity.

Implementing hierarchical cell structure optimizes the radio cell use.

Different layers are differentiated by frequency, coverage and capacity. Two macro layers withexactly identical coverage are illustrated in the lower figure. Each NodeB supports two radiofrequency layers with three sectors (2/2/2 configuration). The radio cells are in the sameNodeB and on the same antenna. The radio access network may be designed usinghierarchical cell structures. Hierarchical cell structures are composed of different layers usingdifferent frequencies. However, different frequencies can also be used on the samehierarchical layer.


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01

1

1

1

222 2

Pico cell

Micro cell

Macro cell

F1 F1 F1

F2 F2 F2

Layer 1 Cells with

RF1

Layer 2 Cells withRF2


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Next figure shows an example of HCS network evolution with 2 carriers (RF1 and RF2). At the firststage only macro layers will be implemented. Next stage another frequency RF2 is expanded inmacro layers areas with overall capacity. Third stage is implemented in specific areas by hot spotcapacity using micro layer RF1. And finally, RF1 macro layer is changed to continuous micro layerfor hot spot capacity with another frequency for hot spot micro layer.


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1) F1 in macro cells

2) F1+ F2 in macro cells

3) F1+F2 in macro cells andF1 in selected micro cells

4) F2 in macro cells andF2 in selected micro cellsF1 in continuous micro cells

F1 F1 F1 F1

F1 F1 F1 F1F1F1

F2 F2

F1F1

F2 F2 F2 F2

Overall capacity

Overall capacity ,Hot spot capacity

Overall capacity ,Hot spot capacity

F1 F1

F1 F1F1,F2 F1,F2

F1 F1F1,F2 F1,F2


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Cell reselection in a HCS case is based on measurements and ranking of the neighbor cells. Thealgorithm differs from the non-HCS case. The main differences are:

Hierarchy is introduced (priorities 0..7);

Measurements of neighbor cells will be triggered if certain HCS-dependent conditions are met. (asdescribed below).

Furthermore, speed sensitivity is considered

HIGH MOBILITY:

For fast moving UEs the procedure is different: If the number of cell reselections during the pasttime period TCRmax (cell hcs tcrmax) exceeds NCR, (cell hcs ncr) high-mobility has been detected.In this high-mobility state, a UE:

measures intra-frequency and inter-frequency neighboring cells, which have an equal or lower

HCS priority than the serving cell;

prioritizes re-selection of intra-frequency and inter-frequency neighboring cells on lower HCS

priority level rather than neighboring cells on the same HCS priority level. When the number of cellreselections during the past time period TCRmax no longer exceeds NCR, UE:

continues these measurements during time period TCrmaxHyst, ( cell hcs tcrmax_hyst) and

reverts to measurements according to the threshold based measurement rules.


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Intra-RAT (FDD):

all cells if [(Squal Sintrasearch else

hcs_prion >= hcs_prios Squal


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Quality level threshold criterion H for hierarchical cell structure is used to determine whetherprioritized ranking according to hierarchical cell reselection rules applies. It is defined by:

HS = Qmeas,s - Qhcss

Hn = Qmeas,n - Qhcsn TOn * Ln

Hn depends on the state of the timer Tn (expired y/n) and priority of the neighbor cell:

TOn = TEMP_OFFSETn * W(PENALTY_TIMEn Tn)

Ln = 0 if HCS_PRIOn = HCS_PRIOs

Ln = 1 if HCS_PRIOn HCS_PRIOs

W(x) = 0 for x < 0

W(x) = 1 for x >= 0

The timer Tn is implemented for each neighbor cell. Tn is started from zero when one of thefollowing conditions becomes true:

if HCS_PRIOn HCS_PRIOs and Qmeas,n > Qhcsn or

if HCS_PRIOn = HCS_PRIOs for serving FDD and neighbor FDD cells if the quality measure forcell selection and reselection is set to CPICH RSCP in the serving cell, and:

Qmeas,n > Qmeas,s + Qoffset1s,n


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HCS Quality Level Threshold:

Hs = Qmeas,s - QhcsS

Hn = Qmeas,n - Qhcsn - TEMP_OFFSETn * W(PENALTY_TIMEN Tn )

if HCS_PRIOn HCS_PRIOs

(Trigger: Qmeas,n > Q hcsn )

Quality Measure Q:Qmeas,n = CPICH RSCP / RxLevQmeas,n = CPICH Ec/No

for serving FDD and neighbor FDD cells if the quality measure for cell selection and reselection is set to

CPICH Ec/No in the serving cell, and:Qmeas,n > Qmeas,s + Qoffset2s,n for all other serving and neighbor cells:

Qmeas,n > Qmeas,s + Qoffset1s,n


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UE measures and ranks the neighbor cells: R criterion. Rn is time - dependent, i.e. neighbor cellsof equal priority get their R lowered during runtime of Tn:

RS = Qmeas,s + Qhysts

Rn = Qmeas,n - Qoffsets,n TOn * (1-Ln)

(Re-) Selected cell:

is a suitable cell (fulfill the S criterion),

fulfill the H criterion (H>=0),

has the highest priority (HCS_PRIO, in high mobility state cells with the lower HCS_PRIO areselected),

and is the best ranked cell (has the highest R).

The UE shall however reselect the new cell, only if the following conditions are met:

the new cell is better ranked than the serving cell during a time interval Treselections.

more than 1 second has elapsed since the UE camped on the current serving cell.


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Ranking of cells:

Quality MeasureQ

meas,n= CPICH RSCP / RxLev Qhyst1ss,n & Qoffset1ss,n

Qmeas,n

= CPICH Ec/No Qhyst2ss,n & Qoffset2ss,n

Re-selected cell: Suitable (S > 0)Highest HCS_PRIO [if H > 0] *)Best Ranked (Highest R)

Rs = Qmeas,s + QhystS

Rn = Qmeas,n Qoffsets,n - TEMP_OFFSETn * W(PENALTY_TIMEn Tn )

if HCS_PRIOn = HCS_PRIOs(Trigger: Qmeas,n > Q meas,s + Qoffsets,n )

*) in high mobility state neighbor cells with lower priorities are selected


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HCS PRIO (0, 1 .. 7) Specifies HCS priority level for serving cells.

QHCS (0.. 99) quality threshold levels for applying hierarchical cell re-selection.

Mapping: qhcs=0..89 > -115..-26dBm (RSCP (FDD) and RXLEV (GSM); qhcs=0..48 > -24..0 dB step 0.5 dB (EcNo FDD)

Penalty time (0, 10 .. 60) s Specifies duration how long Temporary_offset is applied to the neighboring cell.

Temporary Offset1 (10, 20.. 70, inf) dB Offset applied to H and R criteria of the neighboring cell for duration of penaltytime in case quality measurement for cell selection and re-selection is set to CPICH RSCP.

Temporary offset2 (10, 20.. 70, inf) dB Offset applied to H and R criteria of the neighboring cell for duration of penaltytime in case quality measurement for cell selection and re-selection is set to CPICH Ec/No.

TCRmax (0, 30, 60, 120, 180, 240) s Time period for observation of NCR

NCR (1, 2 .. 16) Specifies the maximum number of times of cell reselections.

TCRmaxHyst (0, 10 .. 70) s Specifies additional time period before the UE can revert to low mobility measurements.Value 0 means not used.

SsearchHCS flag (off, on) Specifies whether "Search HCS shall be used

SsearchHCS (-105, -103 .. 91) dB Threshold for HCS cell reselection

SHCS,RAT flag (off, on) Specifies whether "Shcs RAT" shall be used

SHCS,RAT (-105, -103 .. 91) dB Threshold for inter-RAT cell reselection with HCS


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The purpose of handover control is to manage the mobility aspect of a radio resource control(RRC)connection. This means keeping track of the user equipment (UE) as it moves around in thenetwork, and ensuring that ist connections are uninterrupted and meet the negotiated quality ofservice (QoS) requirements.

Besides supporting the mobility of the UE, handovers play a key role in maintaining high capacity inthe network. Since the capacity of a wideband code division multiple access (WCDMA) network isdirectly proportional to the level of interference in the network, it is crucial to regulate thetransmission power of all transmitting elements in the network. Each transmission adds to theinterference in the network. The required transmission power, in turn, depends on the bit rate, theinterference and the distance between the UE and the WCDMA base station (BTS).

Handovertypes:

Softhandover

Hard handover

Interfrequency Handover

Inter-RAT handover from/to UTRAN

Other Mobility related procedures:

Inter-RAT cell reselection from/to UTRAN

Inter-RAT cell change order from/to UTRAN


41/89


+DQGRYHUV

F1 F1

F2 F2 F2

GSM

UMTS micro cells

UMTS macro cells

intersystem HOtriggered by limitedcoverage of UMTS

intersystem HOtriggered by GSM

interfrequency HO

intrafrequency HO(intra Node B)e.g. softer HO

intra-frequency HO(inter Node B or inter RNC) e.g.

soft HO


42/89


EOLQG KDQGRYHU

Timing maintained handover

The uplink transmission timing and the connection frame number in the UE is not changed. The SRNC must knowthe timing difference between the connection frame number and the system frame number of the target cell.

This works only between the Cells belong to the same sector beeing served by one NodeB.

Timing maintained handover is used for blind handover. In all other cases timing re-initialized handover isperformed. A blind handover is an interfrequency handover that does not trigger inter-frequency measurements onthe target cell no measurments and so no compressed mode is needed.

This may be used in the case of poor quality, High load, or due to the support of usage of HSPA.

RRC redirections are usually not referred to as Handovers but can be seen in this context as a simular mechanism,the RRC connection is redirected to the other frequency, for example because the


43/89


EOLQG +DQGRYHUV

F1

F2

Load balancing between the layers

Or

Use one cell as overflow mechanism

F1HSDPA enabled

F2

Load balancing between the layers

Or

Use one cell as overflow mechanism


44/89


6RIWKDQGRYHU

The handover decision algorithm of the RNC is fairly straightforward for soft (and softer) handover:the algorithm accepts practically everything the UE suggests according to the measurementreporting events.

The handover control of the RNC contains the following measurement reporting events andmechanisms for modifying measurement reporting behaviour:

- reporting event 1A for adding cells to the active set

- reporting event 1B for deleting cells from the active set

- reporting event 1C for replacing cells in the active set

- event-triggered periodic intra-frequency measurement reporting

- time-to-trigger mechanism for modifying measurement reporting behaviour

-cell individual offsets for modifying measurement reporting behaviour

- reporting events 6F and 6G for deleting cells from the active set

Due to the heavy load in the cell admission control may reject the request and the RRC connectionof the UE is dropped. The reason for this is that, if the UE branch addition had been allowed, itcould have decreased its transmission power and consequently the amount of interference.Likewise, if the UE were allowed to connect to the second-best candidates, in this case, then theywould have to transmit with unnecessarily high power levels. Lastly, the unnormally hightransmission powers used in such a situation would further deteriorate the situation in the rejectedcell. For this reason the UE may never be connected to the second-best BTS.


45/89


([DPSOH(YHQWF

Reportingevent 1C

Reportingevent 1C

Measurementquantity

Time

P CPICH 2

P CPICH 1

P CPICH 3

P CPICH 4

f in this figure, the parameters hysteresis and time to trigger, as well as the cell individual offsets for all cells areequal to 0. In this example the cells belonging to primary CPICH 1 and 2 are in the active set, but the cellstransmitting primary CPICH 3 and CPICH 4 are not (yet) in the active set.

f The first measurement report is sent when primary CPICH 4 becomes better than primary CPICH 2. The "cellmeasurement event result" of the measurement report contains the information of primary CPICH 4 andCPICH 2.

f Assuming that the active set has been updated after the first measurement report (active set is now primaryCPICH 1 and primary CPICH 4), the second report is sent when primary CPICH 3 becomes better thanprimary CPICH 1. The "cell measurement event result" of the second measurement report contains theinformation of primary CPICH 3 and primary CPICH 1.

A primary CPICH that is not included in the active set becomes better than a primary

CPICH that is in the active set

(actset=2)


46/89


6RIWKDQGRYHU GHFLVLRQ

Measurements

Filtering

Reporting (UE: Event or periodic)

Measurements

Filtering

Reporting (UE: Event or periodic)

Handover Decision:

SHO possible?

(capacity in target cell, Iub/Iur resources,...)

Handover Decision:

SHO possible?(capacity in target cell, Iub/Iur resources,...)

Handover Execution Activate new Node B / Cell

(via Iub, Iur) RRC: Update Active Set

Handover Execution Activate new Node B / Cell

(via Iub, Iur) RRC: Update Active Set

transmitted

to s-RNC

transmitted

to s-RNC

YESYES

No

(or RRCReestablishment)


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0HDVXUHPHQWV

The following conditions are used to trigger a handover:

The operator decides which quantity the UE shall measure in caseof intra-frequency measurements:

f CPICH RSCP Received Signal Code Power

f CPICH Ec/N0 Energy per chip / total noise

f CPICH Pathloss TX-Power RSCP

Measurement quantity for frequency quality estimate (ECNO, RSCP) Measurement quantity forfrequency quality estimate.

Active set size (1, 2, 3, .., 6) Defines maximum number of cells in the active set.

Set in data base per RNC/cell (?)


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0HDVXUHPHQWV

If the IE "Filter coefficient" is received the UE applies filtering of the measurements for thatmeasurement quantity according to the formula below. This filtering is performed by the UE beforeUE event evaluation. The UE filters also the measurements reported in the IE "Measured results".

The filtering is not performed for the measurements reported in the IE "Measured results onRACH" and for cell-reselection in connected or idle mode.

The filtering is performed according to the formula.

Fnis the updated filtered measurement result

Fn-1 is the old filtered measurement result

Mn is the latest received measurement result from physical layer measurements, the unit used forMn is the same unit as the reported unit in the MEASUREMENT REPORT message or the unitused in the event evaluation.

The measurement period is 200 ms.

a= 1/2(k/2), where k is the parameter received in the IE "Filter coefficient".

NOTE: if k is set to 0 that will mean no layer 3 filtering.

nnn MaFaF += 1)1(


49/89


)LOWHULQJ

measurednewfilteredoldfilterednew aMMaM ,,, )1( +=

TS 25.331

Filter coefficient k (0,1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 15, 17, 19) If the IE "Filter coefficient" is received,the UE shall apply filtering of the measurements for that measurement quantity.

k=0 =filterednewM ,

filteredoldM

,k=19 ~filterednewM ,

measurednewM ,


= 1/2(k/2),a


50/89


0HDVXUHPHQWV

The adjustment of the filter coefficient mainly depends on the rate of changes of the radiopropagation conditions. The main effects are:

path loss (change of 2..5 dB) UE movement of 100 m,

long term fading (change of 4..10 dB) UE movement of 5 .. 100 m,

short term fading (change of 20..30 dB) UE movement of 0.07 m.

Hence, at the cell border the main variation of the received level is due to long and

short term fading.

Short term fading:

Even for slow moving UEs (e.g. speed = 3.6 km/h) short term fading can be averaged withrather small values of k.

Long term fading:For slow moving UEs long term fading can be averaged by using rather high values of k.

However, a too high value of k delays HO decision. Hence, the setting of the averagingwindow size has to be a compromise between a fast and a reliable decision.

For faster moving mobiles the problem is not as severe.


51/89


)LOWHULQJ H[DPSOH

-30

-25

-20

-15

-10

-5

0

5

10

0 20 40 60 80 100 120 140

distance [m]

rxsignal[arb.

dB]&filtered

receivedfilteredthreshold

Example (k = 8 UE speed = 3.6 km/h)


52/89


0RQLWRUHG &HOOV

Cells that the UE is monitoring are grouped in the UE into three mutually exclusivecategories:1. Cells, which belong to the active set. User information is sent from all these cells. In FDD, the cells in

the active set are involved in soft handover. In TDD the active set always comprises one cell only.The UE shall only consider active set cells included in the variable CELL_INFO_LIST formeasurement; i.e. active set cells not included in the CELL_INFO_LIST shall not be considered inany event evaluation and measurement reporting.

2. Cells, which are not included in the active set, but are included in the CELL_INFO_LIST belong to themonitored set *.

3. Cells detected by the UE, which are neither in the CELL_INFO_LIST nor in the active set belong tothe detected set. Reporting of measurements of the detected set is only applicable to intra-frequencymeasurements made by UEs in CELL_DCH state.

If the IE "Cells for measurement" has been included in a MEASUREMENT CONTROL message, onlymonitored set cells explicitly indicated for a given intra-frequency (resp. inter-frequency, interRAT)measurement by the IE "Cells for measurement" shall be considered for measurement. If the IE

"Cells for measurement" has not been included in a MEASUREMENT CONTROL message, all of theintra-frequency (resp. inter-frequency, inter RAT) cells stored in the variable CELL_INFO_LIST shallbe considered for measurement.

* or Neighbor set: Monitored cells (candidates) whose measured signal is not strong enough to be addedto the Active set.


53/89


0HDVXUHPHQW &RQWURO IRU ,QWUD)UHT

DCH (VPI/VCI/CID = 0/33/22) DCCH: DL RLC AMD rrcMeasurementControlmeasurementIdentity = 9measurementCommand: setupfmeasurementType: intraFrequencyMeasurement

IntraFreqCellInfoList newIntraFreqCell:

intraFreqCellID = 0, primaryScramblingCode = 162 newIntraFreqCell:

intraFreqCellID = 1, primaryScramblingCode = 163 newIntraFreqCell:

intraFreqCellID = 2, primaryScramblingCode = 164intraFreqMeasQuantity FDD: cpich Ec-No

reportCriteria intraFreqReportingCriteria eventCriteriaList:f Event e1a: triggering condition = monitored set cells only, threshold, hysteresis,

timeToTrigger etc.f Event e1b: triggering condition = active set cells only, threshold, hysteresis,

timeToTrigger etc.f Event e1c: threshold, hysteresis, timeToTrigger etc.

MeasurementReportingMode:fMeasurementReportTransferMode = acknowlededModeRLCf periodicalOrEventTrigger = eventTrigger

UE

FACH CCCH: DL RLC UM rrcConnectionSetup (primaryScramblingCode = 162)


54/89


4XDOLW\ HVWLPDWLRQ

f Frequency quality estimate of the UTRAN frequency QUTRAN

f The estimated quality of the active set in UTRAN in event 3a is defined as:

f The variables in the formula are defined as follows:

QUTRAN is the estimated quality of the active set on the currently used UTRAN frequency.

MUTRAN is the estimated quality of the active set on currently used UTRAN frequency expressed inanother unit.

Mi is the measurement result of cell i in the active set, according to what is indicated in the IE"Measurement quantity for UTRAN quality estimate".

NA is the number of cells in the active set.

MBest is the measurement result of the cell in the active set with the highest measurement result.

W is a parameter sent from UTRAN to UE.

If the measurement result is CPICH-Ec/No MUTRAN, Mi and MBest are expressed as ratios.

If the measurement result is CPICH-RSCP or PCCPCH-RSCP, MUTRAN, Mi and MBest areexpressed in mW.

,10)1(10101

Best

N

i

iUTRANUTRAN LogMWMLogWLogMQA

+

==

=


55/89


5HSRUWLQJ5DQJHZLWK HDDQGHE

e1a e1b

Primary CPICH levelof neighbor cell

Reporting range

Primary CPICH level ofstrongest cell in active set

Signalstrength

time

Reporting range-A/B (0.0, 0.5 .. 14.5) dB Threshold for intra-frequency handover; used with reporting events 1A/B.


56/89


+\VWHUHVLV

Primary CPICHlevel of neighbor

cell 2

Hysteresis

e1a e1b

Primary CPICHlevel of neighbor

cell 1Signalstrength

time

Threshold

f Purpose: eleminate ping-pong effects in P-CPICHmeasurement

- limits the amount of event-triggered reports

- a hysteresis parameter is connected with each reporting event

- value of the hysteresis is given to the UE in the reporting criteria field of the measurement controlmessage

Hysteresis-A/B/C (0.0, 0.5 .. 7.5) dB Hysteresis; applied to reporting events 1A/B/C.


57/89


7LPHWRWULJJHU

Time to trigger

Primary CPICH level

of neighbor cell 2

e1a

Primary CPICH levelof neighbor cell 1

Signalstrength

time

Threshold

f 3XUSRVHHOHPLQDWH VKRUWWLPH SHDNV LQ3&3,&+PHDVXUHPHQWV

Time to trigger-A/B/C (0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000) ms Indicates the periodbetween the event detection 1A/B/C and sending the measurement report.


58/89


(YHQWD

),2/(10)1(1010 111

aaBest

N

i

iNewNew HRLogMWMLogWCIOLogMA

+

+

=

A new radio link will be added to the active set if it fulfils the following criteria for the time to trigger:

Triggering condition:

),2/(10)1(1010 111

aaBest

N

i

iNewNewHRLogMWMLogWCIOLogM

A

++


59/89


(YHQWE

A radio link will be removed from the active set if it fulfils the following criteria for the time to trigger:


Leaving Triggering condition:

The variables in the formula are defined as follows:

MOld is the measurement result (e.g. CPICH Ec/No) of the cell leaving the reporting range.

Mi is a measurement result (e.g. CPICH Ec/No) of a cell in the active set.

NA is the number of cells in the current active set.

MBest is the measurement result (e.g. CPICH Ec/No) of the strongest cell in the active set.

W is the weighting factor defined by O&M.

R1b is the reporting range (active set threshold) for the event 1b.

H1b is the hysteresis parameter for the event 1b.

CIOOld is the cell individual offset of the cell leaving the reporting range.

),2/(10)1()/1(/11010 111

bbBest

N

i

iOldOld HRLogMWMLogWCIOLogMA

+++

+

=

),2/(10)1()/1(/1101011

1

bbBest

N

i

iOldOld HRLogMWMLogWCIOLogMA

++


60/89


(YHQWF

A radio link will be replaced if the active set is full and the following condition becomes true for the timeto trigger


Leaving Triggering condition:

The variables in the formula are defined as follows:

MInAS is the measurement result of the cell in the active set with the lowest measurement result

MNew

is the measurement result (e.g. CPICH Ec/No) of a cell entering the active set.

H1c is the hysteresis parameter for the event 1c.

CIOInAS is the individual cell offset for the cell in the active set that is becoming worse than the new cell.

CIONew is the cell individual offset of the cell entering the active set.

Note, applicable for CPICH RSCP, CPICH Ec/N0.

,2/1010 1cInASInASNewNew HCIOLogMCIOLogM +++

,2/1010 1cInASInASNewNew HCIOLogMCIOLogM +


61/89


0HDVXUHPHQW &RQWURO IRU ,QWUD)UHTXHQF\ +DQGRYHU

R1A H 1A/ 2

Connectionestablishment

Cell 1

Event 1A

Add Cell 2

Event 1C

Replace Cell 1with Cell 3

Event 1B

Remove Cell 3

CPICH 1

CPICH 2

CPICH 3

Time

Measurement

Quantity M

time to trigger time to trigger time to trigger

R1B + H 1B/ 2

H 1C/ 2

(actset=2)


62/89


&HOO,QGLYLGXDO 2IIVHW &,2

f Offset can be positive or negative

f Purpose: speed up or slow down handover into strong/weakcells

Threshold

PositiveOffset

Original PrimaryCPICH level

e1a

Primary CPICH levelplus positive offset

Signalstrength

time


63/89


1HLKERXU FHOOSDUDPHWHUV

Cell

Adjacent Cells

(same F)

Cell individual offset (-50, -49 .. 50) dB Offset to be applied by the UE to the measurement.

Adjacent Cells(same F)

Cell Reselectionpossible

Cell(same F)

Not defined as neighbour, no CellReselection, no Soft-handover

possible

f CIO Is defined on adjacency basis!

f It is possible to restrict neighbour relations to idle mode only!


64/89


,PSDFWRI:RQWKH DFWLYH VHW

W increases the quality (QUTRAN ) of the active set (strongest and other cells in the activeset are weighted against each other, in use for 1a and 1b).

Example:

- W = 0 QUTRAN determined by the strongest CPICH- W > 0 impact of the rest of the cells increases


65/89


6RIWKDQGRYHU SDUDPHWHUVReporting range-A (0.0, 0.5 .. 14.5) dB Threshold for intra-frequency handover;

used with reporting events 1A.

Weighting factor-A (0.0, 0.1 .. 2.0) Used for calculation of Q_UTRAN; applied to reporting events 1A.

Hysteresis-A (0.0, 0.5 .. 7.5) dB Hysteresis; applied to reporting events 1A.

Time to trigger-A (0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000) ms Indicates the periodbetween the event detection 1A and sending the measurement report.

Amount of reporting-A (1, 2, 4, 8, 16, 32, 64, inf ) Indicates the maximum number of measurement reports to betransmitted, which are triggered in a cell by event 1A; inf = infinity.

Reporting interval-A (0, 250, 500, 1000, 2000, 4000, 8000, 16000) ms Indicates the interval to send reports triggered byevent 1A.

Reporting range-B (0.0, 0.5 .. 14.5) dB Threshold for intra-frequency handover; used with reporting events 1B.

Weighting factor- B (0.0, 0.1 .. 2.0) Used for calculation of Q_UTRAN; applied to reporting events 1B.

Hysteresis-B (0.0, 0.5 .. 7.5) dB Hysteresis; applied to reporting events 1B.

Time to trigger-B (0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000) ms Indicates the periodbetween the event detection 1B and sending the measurement report.

Hysteresis-C (0.0, 0.5 .. 7.5) dB Hysteresis; applied to reporting events 1C.

Time to trigger-C (0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000) ms Indicates the periodbetween the event detection 1C and sending the measurement report.

Amount of reporting-C (1, 2, 4, 8, 16, 32, 64, inf ) Indicates the maximum number of measurement reports to betransmitted, which are triggered in a cell by event 1C; inf = infinity.

Reporting interval-C (0, 250, 500, 1000, 2000, 4000, 8000, 16000) ms Indicates the interval to send reports triggered byevent 1C.



66/89


0HDVXUHPHQW 5HSRUWIRU ,QWUD)UHT

DCH (VPI/VCI/CID = 0/33/22) DCCH: DL RLC AMD rrcMeasurementReportmeasurementIdentity = 9measuredResults:f intraFrequencyMeasuredResultList:

CellMeasuredResults primaryScramblingCode = 162 Cpich-Ec-No = 35

CellMeasuredResults primaryScramblingCode = 163 Cpich-Ec-No = 30

eventResults intraFreqEventResults:

f eventID = e1a primaryScramblingCode = 163

UE

DCH (VPI/VCI/CID = 0/33/22) DCCH: DL RLC AMD RRC ActiveSetUpdate(rlAdditionInfomationList primaryScramblingCode = 163)

DCH (VPI/VCI/CID = 0/33/22) DCCH: DL RLC AMD RRC ActiveSetUpdateComplete

NBAP Radio Link Setup or Radio Link Addition


67/89


&RPSUHVVHG PRGH

f Start of Compressed mode either by 2D or event 6A (UE Txpower)

f

event 2Dstart measurements

time

Qused

event 2Fstop measurements

Tused2D

Tused2F H2F/ 2

H2D/ 2

- UE monitors within transmission gap all adjacent cells having another carrier than the serving cell orall adjacent GSM cells.

- As monitored quantities are used CPICH EC/I0 and RSCP for adjacent interfrequency UMTS cells orBCCH Rx level for adjacent GSM cells

- Sampling and filtering differs from that of intrafrequency measurements due to compressed mode


68/89


,PSDFWRIFRPSUHVVHGPRGH

Change of air interfaceperformance

Change of air interface

performance

In case of SF halfing orpuncturing more Tx powerneeded

In case of SF halfing orpuncturing more Tx powerneeded

Slightly moreinterference

Slightly moreinterference

Slight loss ofcapacity

Slight loss ofcapacity

No fast PC duringtime gaps

No fast PC duringtime gaps

Higher Eb/N0required

Higher Eb/N0required

(Strong) loss ofcoverage

(Strong) loss ofcoverage


69/89


,QWUDIUHTXHQF\ +DQGRYHUW\SHV

f inter-frequency handover due to Uplink dedicated traffic

channel (DCH) quality

f inter-frequency handover due to UE transmission power

f inter-frequency handover due to Downlink dedicated physicalchannel (DPCH) power

f inter-frequency handover due to common pilot channel(CPICH) RSCP

f inter-frequency handover due to CPICH Ec/Nof load-based handover

f service-based handover


70/89


(YHQW'

event 2D(QUTRAN)

Time

QUTRANLeavingtriggeringcondition

Triggeringcondition

T2DH2D

event 2D(QUTRAN)

The trigger event 2D is used to detect the current frequency quality. This triggered inter-frequency handover enablesto move from a frequency layer to another frequency layer, when the quality of the current used frequency becomesworse.

When the estimated quality of the currently used frequency is below the value of the information "threshold usedfrequency" and the "hysteresis and time to trigger conditions are fulfilled:

"The estimated quality of the currently used frequency is below a certain threshold"

2/22 ddUsedUsed HTQ

2/22 ddUsedUsed

HTQ +

'Weighting factor' and 'time to trigger' are applied in an analogous way as described above (see "Intra-frequency handover").


71/89


3DUDPHWHUVf Measurement quantity for frequency quality estimate (ecn0, rscp) Measurement quantity for

frequency quality estimate

f Filter coefficient (0,1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 15, 17, 19) If the IE "Filter coefficient" is received,the UE shall apply filtering of the measurements for that measurement quantity.

f Enable CM HO without CM (false, true) If set to true inter-frequency HO without compressed mode isenabled.

f W used frequency for event 2A (0.0, 0.1 .. 2.0)

f Hysteresis for event 2A (0.0, 0.5 .. 14.5) dB

f Time to trigger for event 2A (0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560,5000) ms

f W non used frequency for event 2A (0.0, 0.1 .. 2.0)

f Threshold of used frequency for event 2B (-115, -114 .. 0) dB, dBm (for -115 to - 25 measurementquantity is RSCP otherwise Ec/No.)

f W used frequency for event 2B (0.0, 0.1 .. 2.0)

f Hysteresis for event 2B (0.0, 0.5 .. 14.5) dB

f Time to trigger for event 2B (0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560,5000) ms

f Threshold of nonused frequency for event 2B (-115, -114 .. 25) dBm (For measurement quantity isRSCP.)

f Threshold of nonused frequency for event 2B (-24, -23 .. 0) dB (For measurement quantity Ec/No.)

f W non-used frequency for event 2B (0.0, 0.1 .. 2.0)


72/89


$DQG%HYHQWV

Non used frequencyExample 2A

Hysteresis2A

Quantity

Time

Non used frequency

Example 2BThreshold non used frequency above

Threshold used frequency below

Time to trigger

Reporting event 2a

Time to trigger

Reporting event 2b

Event 2A (change of best frequency)

and

Event 2B (coverage limitation of used frequency)


73/89


+DQGRYHU WR*60CS-ONLY AND CS+PS:

INTER SYSTEM HO EVENTS

Event 2D: "The estimated quality of the currently used frequency is below a certain threshold"

Event 2F: 'The estimated quality of the currently used frequency is above a certain threshold'

Event 3A: "Estimated quality of the currently used UTRAN frequency is below a certain thresholdand the estimated quality of the other system is above a certain threshold."

The handover algorithm is based on the events 2D, 2F and 3A.

Upon reception of event 2D, event 3A and event 2F are set and inter-system measurement /

compressed mode is started.

If event 2F is received before event 3A, compressed mode is deactivated and the UE remains inthe UTRAN. Inter system-handover is triggered upon reception of event 3A (fig.18).

The reporting quantities for the current UTRAN frequency can be one of:

CPICH Ec/N0

CPICH RSCP

The measurement and reporting quantities for GSM measurements will be one or several of thefollowing:

BSIC

GSM carrier RSSI


74/89


event 2Dstart inter- system

measurements

FDD CPICHUsed system

time

MotherRATQUTRAN, used f GSM RXLEV

event 3Ahandovertriggered

TotherRAT + H 3A/ 2-CIOotherRAT

Tused H 3A / 2

Tused2D H 2D / 2

Tused2F + H 2F / 2

+DQGRYHU WR*60A parallel PS call will be released in UTRAN on request of SGSN or on timeout. It may be reinitiated by

the UE in the target GSM/GPRS cell (class A UE).


75/89


36+DQGRYHU WR*356

PS-ONLY CASE: CELL CHANGE ORDERThe purpose of the cell change order procedure is to transfer a UTRAN PS RAB connection to aGSM/GPRS cell under the control of the UTRAN. The UTRAN orders the UE to perform a cell

change to a GSM/GPRS cell if the radio condition quality measurements are below a certainthreshold and the GSM measurement quality is above a certain threshold.

The conditions for the cell change order procedure are:

The UE is in CELL_DCH state AND

Only PS RAB(s) exist AND

No signaling connection to the CS domain exists

The cell change order procedure is applied to UEs with PS RAB(s) regardless of the service (besteffort, streaming,), provided that the UE is in CELL_DCH state. If a UE has both, CS and PSRABs, the CS call has the highest priority. In this case, the UMTS to GSM handover procedure isstarted instead of the cell change order procedure,

Cell change order has to be enabled and applies for PS-only connections.


76/89


$3DUDPHWHUV

Threshold own system for event 3A (-115, -114 .. 0) dB Absolute threshold UTRAN forIntersystem

measurement event 3A reporting criteria (values from -115 to -25 represent RSCP, above Ec/N0)

Threshold other system for event 3A (115, -114 .. 0) dBm Absolute threshold GSM for Inter-system measurement event 3A reporting criteria

W for event 3A (0.0, 0.1 .. 2.0) Weighting factor for Inter-system measurement event 3A reportingcriteria

Hysteresis for event 3A (0.0, 0.5 .. 7.5) dB Hysteresis for Inter-system measurement event 3Areporting criteria

Time to trigger for event 3A (0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560,5000] ms Indicates the period of time between the timing of event 3A detection and the timing ofsending Measurement Report.


77/89


*60FHOO3DUDPHWHUV

MCC ( 000, 001 .. 999) Mobile country codeMNC (00, 01 .. 99 or 00, 01 .. 999) Mobile network code

GSM LAC (1, 2 .. 65533, 65535) GSM location area code

GSM cell ID (0, 1 .. 65535) GSM cell id

ARFCN (0, 1 .. 1023) RF channel number

NCC (1 .. 79 Network color code

BCC (0, 1 .. 7) Base station color code

Band indicator egc bandi dcs, pcs none dcs = dcs1800, pcs = pcs1900

Max UL Power egc maut -50, -49 .. 33 dBm Maximum allowed UL Tx power

Qrxlevmin egc qrxlevmin -115, -113.. -25 dBm Minimum required RX Lev

Network control mode egc mode_nc 0, 1, 2, 3 none Controls the UE measurement behavior

that is to be applied in target GPRS cell.

Set per adjacency:

Cell individual offset (-50, -49 .. 50) dB Offset to be applied by the UE to the measurement.


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f Every new requested bearer has to be evaluated by RRM algorithms. Packet schedulingfunctionality defines a possible set of transport channel formats (possible bit rates) fro non-realtime services.

f For every proposed bit rate, admission control functionality has to calculate the power, which willbe needed to establish the connection with the sufficient quality. If the RTWP increased by newuser will be bellow the cell load target value, the new bearer will be admitted. If it will be above thislimit, but still below cell load target value increased by offset, only packet scheduler functionalitycan take the decision about an admission of the new bearer. Nevertheless, the existing bearersshould be recalculated (in order to prevent a possible overload situation). In case the increasedthreshold is broken, an overload algorithm should decrease the existing bit rates.

f When switching between common channels (RACH/FACH) for low bit bearers and dedicatedchannels for high bit bearers, packet scheduler effectively uses a short radio interface resourcesand keeps the load below the target threshold.


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RTWP < PRX Target+ Pj

RTWP < PRXTarget+ Offset + Pj

re-/allocate bit rates

increase load

decrease load

YES

YESNO

NO

Were:

RTWP = received totalwideband power

PRX Target = threshold fro

the allowed cell load

Pj = estimated powerneeded for the newconnection j


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f During the RAB assignment procedure for packet switched bearers, a RNC calculates theparameters for traffic volumes measurements (as size of the RLC buffer or volume reportingcriteria for UE).

f Periodically, or triggered by an event, the UL reports are sent to the RNC to indicate a resourcestatus or a need for dedicated capacity.

f Status of the DL used capacity is indicated internally inside of RNC and is not provided in anyprotocol message.

f Two events for volume measurements are defined:

4A:Transport Channel Traffic Volume becomes larger than an absolute threshold

4B:Transport Channel Traffic Volume becomes smaller than an absolute threshold

f The reported quantity are as follows:

Buffer Occupancy, which indicates a number of bits available for the re-/transmission in theRLC layer

Average of Buffer Occupancy and

Variance of the Buffer Occupancy


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WLPH

EVENT 4A

EVENT 4A

EVENT 4B

EVENT 4B

EVENT 4A

Transport

Ch

anne

lT

rafficV

olu

me

4A:Transport Channel Traffic Volumebecomes larger than an absolute threshold

4B:Transport Channel Traffic Volumebecomes smaller than an absolute threshold


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Traffic volumemeasurement results

>RLC Buffers Payload Enumerated (0, 4, 8, 16, 32, 64, 128, 256, 512,1024, 2K, 4K, 8K, 16K, 32K, 64K, 128K, 256K,512K, 1024K)

In bytesAnd N Kbytes = N*1024 bytes.Twelve spare values are needed.

>Average of RLC BufferPayload

Enumerated (0, 4, 8, 16, 32, 64, 128, 256, 512,1024, 2K, 4K, 8K, 16K, 32K, 64K, 128K, 256K,512K, 1024K

In bytesAnd N Kbytes = N*1024 bytes.Twelve spare values are needed.

>Variance of RLC BufferPayload

Enumerated (0, 4, 8, 16, 32, 64, 128, 256, 512,1024, 2K, 4K, 8K, 16K)

In bytesAnd N Kbytes = N*1024 bytes.Two spare values are needed.


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5HVHOHFWLRQ 3DUDPHWHUV

During idle mode cell re-selection is done for circuit and packet switched services but cell re-selection happens also during connected mode for packet switched services. Cell re-selectionmethods from GSM to WCDMA and from W CDMA to GSM are performed differently. Therefore youneed to define how the cell re-selection procedures for the user equipment in the idle or connectedmode are performed. Cell re-selection parameters are planned for different types of userequipment: non-GPRS and GPRS capable phones. Cell re-selection within UMTS and fromGSM to WCDMA is performed by the user equipment.

Benefits of the cell re-selection to GSM:

- Less location updates are performed, provided micro and macro (WCDMA and GSM) layers exist.

- The number of handovers is reduced from WCDMA to GSM.

Benefits of cell re-selection to WCDMA:

- 3G services are available for all dual-mode mobiles even without a GSM to WCDMA handover ora network controlled cell re-selection. Due to the compressed mode, possible loss of coverage orcapacity is decreased.

- The W CDMA network is utilized in a maximum way.


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If the serving cell (or cells participating in soft handover) has neighbour cells both on anothercarrier frequency and on another radio access technology (GSM), the RNC determines thepriorities between inter-frequency and inter-system handovers on the basis of Service HandoverIE value. The RNC receives the Service Handover IE from the core network in the RABASSIGNMENT REQUEST or RELOCATION REQUEST (RANAP) message.

- Should be handed over to GSM:

Inter-system handover takes precedence over inter-frequency handover. In this case the RNCdoes not start inter-frequency measurements until the inter-system measurements have beencompleted, that is, when no neighbour GSM cell is good enough for the quality and/or coveragereason handover.

- Should not be handed over to GSM:

Inter-frequency handover takes precedence over inter-system handover. In this case the RNCdoes not start the inter-system measurements until the inter-frequency measurements have beencompleted, that is, when no neighbouring cell is good enough for the quality and/or coverage

reason inter-frequency handover.

- Shall not be handed over to GSM:

In this case, the RNC does not start inter-system measurements or handover to GSM even if noneighbour cell is good enough for the quality and/or coverage reason inter-frequency handover.This means that the RNC does not initiate handover to GSM for the UE unless the RABs with thisindication have first been released with the normal release procedures.


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RAB assignment

RAB Assignment Request

RAB Assignment Response

RANAP

Radio Link Reconfiguration

AAL2 Setup (real time RAB)

AAL2 Setup (CS RAB)RRC: RB Setup

RRC: RB Setup Complete

RAB Assignment Response

One or several responses

Service Handover IE value:

Should be handed over to GSM

Should not be handed over to GSM

Shall not be handed over to GSM

Service Handover IEvalue is set in CN


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Inter-system handover of packet-switched services between WCDMA and GSM/general packetradio service (GPRS) is based on the cell reselection procedure.

The RNC supports network-initiated cell reselection from WCDMA to GSM/GPRS in CELL_DCHstate of connected mode. In CELL_PCH and URA_PCH states of connected mode, the cellreselection is initiated by the UE. The RNC does not support cell reselection from WCDMA toGSM/GPRS in CELL_FACH state of connected mode (however, a UE equipped with a dualreceiver can perform the cell reselection also in CELL_FACH state).

The RNC sees the cell reselection from GSM/GPRS to WCDMA as an radio resource control(RRC) connection establishment, and the UE-initiated cell reselection from WCDMA to GSM/GPRSas an Iu connection release.


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In CELL_FACH state, the UE shall be able to monitor up to

- 32 intra frequency FDD cells and

- 32 inter frequency cells, including

- FDD cells distributed on up to 2 additional FDD carriers and

- Depending on UE Capability, TDD mode cells, distributed on up to 3 TDD carriers, and

- Depending on UE capability, 32 GSM cells distributed on up to 32 GSM carriers.

-Depending on UE capability, the UE shall be able to monitor up to 16 intra frequencycells during IPDL gaps.


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Directed Retry

Directed Retry is applicable for a RAB assignment from the CSdomain if a target cell for a blind inter-system handover can befound. The RAB ASSIGNMENT RESPONSE message is sentwith the RAB Failed to Setup IE set to Directed Retry.

Cell D

Cell E

Cell F

Cell CCell A

Frequency 2

Frequency 3 (GSM)UE camps on UMTS cell,when a voice call is

established and the UMTScell is full the UE when

support for GSM is given-can be handed over to GSM

without any measurementreport!

Prerequisite is that the GSMcell has the same coverageas the UMTS cell and that

zthis is defined in thedatabease

C 6 6270 Optimization 002 KH

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