nemo - events and definition

7/30/2019 Nemo - Events and Definition

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Topics

1.Nemo Events and Definition

2.RRC and Layer3 messages

3.SIB Information,Measument Control (MC),Measurement Report (MR)

4.CS and PS Call Flow

5.Cell Reselection, SHO and ISHO


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Nemo Events and Definitions


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MOC

M

T

C

MOC/MTC Call Flow timing


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Block error ratio:BLER is measured from the CRC

Transport Block (TB) is a basic unit that is exchanged

between Layer 1 and Layer 2 (MAC). Layer 1 adds

CRC for each TB and BLER is calculated from the CRC


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Cell update causes in priority order:

Uplink data transmission in URA_PCH, CELL_PACH Paging response in URA_PCH, CELL_PACH

Radio link failure in CELL_DCH (*)

Re-entering service area in CELL_FACH, CELL_PCH

RLC unrecoverable error in all sub-states

Cell reselection in CELL_FACH, CELL_PCH

Periodical cell update in CELL_FACH, CELL_PCH

URA update causes in priority order:

(the UE is in the URA_PCH sub-state)

URA reselection

Periodic URA update

When do I

have to

perform a

cell/ URAupdate?


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RRC and Layer-3 Messages

System Information Blocks (SIB)


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RRC Modes


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What are the characteristics of the individual sub-states, when the UE is in the RRC connected mode?

CELL_DCH

In this sub-state, dedicated physical channels are allocated to the UE. DCCH and if configured DTCH information can be transmitted.There no need to identify the UE on a dedicated channel, because the physical channels are exclusively allocated to this UE. UTRAN

knows the active set cells for the radio links and thus the location of the the UE. Also downlink shared channels can be allocated to the

UE.

In this state, the UE is capable to receive RRC messages on the DCCH (and BCCH, if it owns specific capabilities). The cell system

information is broadcasted on the FACH. The UE reads the cell system information and acts accordingly. For instance, it determines the

measurement quality and the reporting events from the cell system information.

CELL_FACH

This state was introduced for traffic situations, where only small amounts of data have to be transmitted. This is the case when only

higher layer signalling information (NAS signalling) or small amount of user data (e.g. SMS messages) have to be transmitted. In this

case, an exclusive allocation of one physical channel to the UE would result in a waste of resources.

The UE is capable to receive and transmit DCCH and if configured DTCH information. Only common transport channel FACH can be

used by the UE to transmit higher layer data, which it has to share with other UEs. Each UE must be explicitly addressed, for instance by

the RNTI. It has to monitor the FACH permanently in the downlink, not to miss user data for it. The UEs FACH is mapped on one S-CCPCH. In the uplink, it uses the shared transport channels for user data transfer, such as the RACH.

The UE is only connected to one cell, and this is the location information, known within UTRAN. No soft handover takes place in this sub-state. The UE is responsible for cell re-selection. By listening to the cell system information from the BCCH, it gains all relevant

measurement qualities, threshold values, neighbourhood lists to perform the cell re-selection process. Other relevant information is also

learned from the BCCH. The UE receives RRC messages on the BCCH, CCCH and DCCH channels.

Due to the discontinuous type of traffic, UTRAN can command the UE to perform periodic cell updates.

CELL_PCH

In this sub-state, the UEs current cell is known to the RNC. If the RNC wants to exchange data with the UE, it only needs to page the UEthere. If the UE changes the cell, it must perform a cell update. Also periodical cell updates can be requested by UTRAN. To performupdates, the UE must change to the CELL_FACH sub-state. (Please note, that no uplink transmission is allowed in

CELL_PCH/URA_PCH.)

URA_PCH

URA stands for UTRAN Registration Area. If the UE is in the CELL_PCH and moving fast, a lot of cell updates have to be performed.

URAs are a combination of one or several cells under one C-RNC. URAs may overlap, i.e. a cell may belong to several URAs. If UTRAN

wants to transmit something to the UE, it must page the UE within the URA. The UE is responsible for URA updates when it changes the

URA and periodic URA updates when required by UTRAN.


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States of Bearer Allocation


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System InformationWithin UTRAN system information is broadcasted with the help of the RRC messages

System Information,

Paging Type I, and

System Information Change Indication.

Most system information parameters are determined by the RNC. The Node B is informed about the

parameters via the NBAP message BCCH Information. Some system parameters can be made

available by the Node B, such as interference values, which change fast. Given the system

information, the UE is capable to decide, whether or how to access the PLMN via the existing cell.

System information is organised in System Information Blocks (SIBs). System information is grouped into

SIB 1 to SIB 18. Each SIB is responsible to carry a specific content. For instance, SIB 12 holdsmeasurement control information and parameters. Depending on the UEs RRC state, it reads specific

SIBs, and uses the transmitted parameters.

There is a huge amount of SIBs, which have to be read by the UE. This requires a lot of battery power.

Therefore, a Master Information Block (MIB) was introduced, which gives references and scheduling

information about the SIBs. The MIB is transmitted in every 8th radio frame on the P-CCPCH (on

position SFN mod 8 = 0, and with a TTI of 20 ms).

For most of the SIBs used within the system, the MIB may carry a value tag. The only exceptions are SIB

15.2, SIB 15.3 and SIB 16. If a value tag is unchanged, the corresponding system information has not

been modified. Thus, there is no need for the UE to read the SIB. SIB 7 has no value tag. It changes

with each occurrence.

Scheduling information is used to inform the UE, where and when a specific system information is

transmitted.


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Node B

UTRANSystem Information ( )

UE RNC

NBAP: BCCH Information

MIB

value tag M

SIB 1

value tag 1

SIB 2

value tag 2

SIB 3

value tag 3

SIB 18

value tag 18

position on P-CCPCH: SFN mod 8 = 0

TTI: 20 msvalue tag M: range 1..8

NBAP = Node B

Application Part


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UTRAN can notify UEs, that a value tag in the MIB has been changed. Hereby, the information element BCCH Modification Info is broadcasted. There aretwo RRC messages, which can carry this information element:

Paging Type 1

Some mobile phones have no radio link allocated, mobile phones, which are in the RRC idle mode, and in the RRC connected mode sub-states

CELL_PCH and URA_PCH. This paging message is transmitted in all paging occasions in the cell.

System Information Change Indication

With this message, we address UEs in the CELL_FACH sub-state. Consequently, this message must be transmitted on every S-CCPCH, which carries

FACHs. The System Information Change Indication message is transmitted on a BCCH, which must be mapped on FACHs in such a way, that every S-

CCPCH carries the BCCH Modification Change IE.

Within the IE BCCH Modification Change, even a BCCH Modification Time can be given, indicating to the UEs, when the value tags will change.

Please note, that UEs in the CELL_DCH sub-state are addressed directly by the RNC via the Measurement Control message.


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In this course documentation, we only describe the System Information Blocks (SIBs), which are used in Nokias RAN1, and


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In this course documentation, we only describe the System Information Blocks (SIBs), which are used in Nokia s RAN1, and

SIB 4 and SIB16. Please note, that all SIBs are valid on cell level except for SIB 1, SIB 15.3, and SIB 16. SIB 1 and SIB

15.3 are valid on PLMN level, while SIB 16 is valid for equivalent PLMNs.


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For each SIB, following characteristics were specified:

Area scope: Where is the value tag valid: within one cell or within a PLMN/ equivalent PLMN?

UE RRC state: When the SIB is valid?

UE RRC state: When the SIB is read?

Scheduling information: At which position is the SIB transmitted and what is its repetition period?

Modification of system information: Is it indicated by a value tag, or is it timer based?

The UE receives all SIBs via the BCCH. There is only one exception: SIB 10. If a UE is capable to receive simultaneously one S-

CCPCH and one DPCH, than it receives SIB 10 on a FACH.

Master Information Block (MIB):

The MIB informs the UE about the supported PLMN types and the PLMN identity. The UE finds in the MIB also references to up

to maxSIB (=32) SIBs, including their scheduling information and type.

A MIB is valid in one cell. If a UE changes the cell, is must read the new cells MIB. The MIB is read in the RRC modes/states

RRC idle, CELL_FACH, CELL_PCH and URA PCH. Its parameter are valid in the same states. A change of the MIB informationis indicated by a value tag.

In this course documentation, we only describe the System Information Blocks (SIBs), which are used in Nokias RAN1, and SIB 4

and SIB16. Please note, that all SIBs are valid on cell level except for SIB 1, SIB 15.3, and SIB 16. SIB 1 and SIB 15.3 are valid

on PLMN level, while SIB 16 is valid for equivalent PLMNs.

SIB1


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SIB1System Information Block 1 (SIB 1)

This SIB is used to inform the UE about NAS system information. The NAS

system information characterises the NAS domains. SIB 1 also delivers

UE timers and counters, which have to be used by the UE in the RRC idle

and RRC connected mode.

For instance, a UE in the RRC connected mode uses the timer T305 for

periodic cell and URA updates.

SIB 1 is valid in one PLMN. The MIB is read in the RRC modes/states

RRC idle, CELL_FACH, CELL_PCH and URA PCH. Its parameter are

valid in the same states, and the the RRC sub-state CELL_DCH. If the UE

selects a new cell, and the SIB 1 value tag has the same number as in the

preceding cell, the same content is transmitted in this SIB. There is thenno necessity for the UE to read this SIB after cell re-selection.

T302/N302 The CELL UPDATE/URA UPDATE retransmission timer (MS

timer)

T300/N300 The RRC CONNECTION REQUEST retransmission timer (MS

timer)

T312/N312 The timer for supervising successful establishment of a

physical channel (MS timer)

T309 The timer for supervising successful connection establishment in case of

an inter-RAT cell re-selection (MS timer)

T316 This timer is started when the UE detects an out of service area inURA_PCH or CELL_PCH state. This timer is stopped when the UE detects an

in service area. When the timer expires the UE initiates cell update procedure

(MS timer).

T317 This timer is started when the T316 expires and the UE detects an out

of service area. This timer is stopped when the UE detects an in service area.When the timer expires the UE transits to idle mode (MS timer)


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SIB2

System Information Block 2 (SIB 2)

This SIB contains an URA identity list.

SIB 2 is read and valid in the RRC sub-state URA_PCH. A change of the SIB 2 information is indicated by a value tag.


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This SIB contains relevant parameters for cell selection and re-selection. It

also holds the cell identity and cell restriction data, such as cell barred

IEs. SIB 3 must be read and is valid in the RRC idle mode. It is read and

valid in the RRC connected mode sub-states CELL_FACH, CELL_PCH

and URA_PCH, if SIB 4 is not broadcasted. A change of the SIB 3

information is indicated by a value tag.


This SIB holds mostly the same data fields as SIB 3, but it is read and valid only, when the UE is in the RRC

connected mode. I.e, this optional SIB is read and valid in the CELL_FACH, CELL_PACH and URA_PCH sub-

state. A change of the SIB 4 information is indicated by a value tag.



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The parameters for the configuration of physical channels are broadcasted in this SIB. The parameters cover

the PICH power offset, the AICH power offset, P-CCPCH, S-CCPCH and PRACH system information lists. SIB5 must be read and is valid in the RRC idle mode. It is read and valid in the RRC connected mode sub-states

CELL_FACH, CELL_PCH and URA_PCH, if SIB 6 is not available. A change of the SIB 5 information is

indicated by a value tag.


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SIB7


This SIB holds fast changing parameters. Therefore no value tag is used for it. The UE has to read its parameters

periodically. For that, an expiration timer (Expiration Time Factor) is broadcasted with this message. SIB 7 expires at

max(32, 8 * Expiration Time Factor). Expiration Time Factor can have the values 2times, 4 times, 8 times ... 256times. Its default value is 1.

The fast changing parameters transmitted with SIB 7 include the UL interference and dynamic persistence level. It is

read and valid in all states except for the CELL_DCH sub-state.

SIB11


This SIB holds measurement control information. The UE gets here the relevant date for traffic measurement, intra-


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SIB11g ,

frequency measurements, etc. SIB 11 must be read and is valid in the RRC idle mode. It is read and valid in the RRC

connected mode sub-states CELL_FACH, CELL_PCH and URA_PCH, if SIB 12 is not broadcasted. It is also valid in

the RRC sub-state CELL_DCH, as long as the UE did not get a Measurement Control message from UTRAN and

SIB 12 is not broadcasted. A change of the SIB 11 information is indicated by a value tag.


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SIB11


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SIB11


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SIB12 System Information Block 12 (SIB 12)SIB 12 transmits measurement control information for UEs in the RRC connected mode. If not transmitted,

the UEs take the parameters broadcasted with SIB 11. If available, SIB 12 is read and valid in the RRC

connected mode sub-states CELL_FACH, CELL_PCH and URA_PCH. It is also valid in the RRC sub-state

CELL_DCH, as long as the UE did not get a Measurement Control message from UTRAN. A change of the

SIB 12 information is indicated by a value tag.


RB, TrCH, and PhyCH parameters are broadcasted, which are stored by the UE both in the RRC idle and

RRC connected mode. The parameters are used during a handover to UTRAN. Consequently, these

parameters stay valid, when the UE is connected to GSM and GPRS.

This SIB is valid in all RRC states, and read in all RRC states except for the CELL_DCH. The UE reads and

stores the parameters. A change of the SIB 16 information is indicated by a value tag.

SIB16


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Voice and Video are both ConversationalRRC messages information - CS

DL SRB


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UE in DUAL MODE UE in 3G LOCKED MODE


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Voice AMR

CS call, 64Kbps,

Transparent

Video Call


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Video CS 64:

DL SF 32

UL SF 16

Voice AMR:

DL SF 128UL SF 64(16 Kbps,12.2kbps)

PS can also be OriginatingHighPrioritySignalling And

Registration (Only for Attach)


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RRC messages information - PSRegistration (Only for Attach)


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Modify max bit rate by Nemo


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SIM Card QoS profile


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Measurement Control (MC) and Measurement Report (MR)


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( ) p ( )

UTRAN controls the measurements in the UE, either by

broadcasting system information on the BCCH, and/or by

transmitting a Measurement Control message on the DCCH.

If the UE is in the RRC idle mode, it receives relevant measurement information from the BCCH. TheSIB type 3 contains parameters for cell selection and re-selection. In parallel, the SIB type 11 is used

to deliver measurement control information to the UE for the serving cell. SIB 3 and SIB 11are read

and valid in the RRC idle state.

If the UE is in the RRC sub-states CELL_FACH, CELL_PCH and URA_PCH, it is connected to one cell

only and responsible for cell selection and re-selection. It retrieves the parameters for cell selection

from SIB type 4. The measurement control information is broadcasted with SIB type 12. SIB 4 and SIB

12 are read and valid, when the UE is in the CELL_FACH, CELL_PCH and URA_PCH sub-state. IfSIB 4 resp. SIB 12 is not broadcasted, then SIB 3 resp. SIB 11 parameters are used instead.

In the sub-state CELL_DCH, the UE is not reading the SIB type 3/4 and 11/12. The parameters of SIB

12 (SIB 11, if SIB is not available) can be still valid in this state.

The RRC message Measurement Control can be transmitted to the UE, if a DCCH has been setup

between the UE and UTRAN. This message informs the UE about the type of measurement, which

has to be conducted. Each measurement command links a measurement with a measurement identity,

quantity, objects, reporting quantities, reporting criteria, type, etc.


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Node B

UTRAN

RNC

UE

System Information

[BCCH]

I am in the

RRC idle mode

Node B

UTRAN

RNC

UE

System Information

[BCCH]

I am in the

CELL_FACH, CELL_PCH or

URA_PCH sub-state

Node B

UTRAN

RNC

UE

Measurement Control [DCCH]I am in the

CELL_DCH sub-state

SIB 3 & SIB 11

SIB 4 & SIB 12

(SIB 3 & SIB 11)

SIB 3 [4]: parameters for cell selection and re-selection [in the RRC connected mode]

SIB 11 [12] : measurement control information [in the RRC connected mode]

read and valid: idle, CELL_FACH, CELL_PCH, URA_PCH.

(SIB 11/12 is also valid in the CELL_DCH.)



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How does a UE perform measurements after a transition in the CELL_DCH state. Two cases have to be

distinguished:

Transition from the RRC idle state to the CELL_DCH sub-state

In the RRC idle state, the UE retrieved the measurement control parameters from the SIB type 11.Information Elements, which contain intra-frequency, inter-frequency, inter-RAT and traffic volume

measurement system information, may be included in the SIB 11. If they are included, the UE can

send a measurement report, when a measurement reporting criteria is fulfilled.

As soon as the UE receives a Measurement Control message including one of the above mentioned

measurement types, it replaces its internal stored data based on the SIB11 by the parameters

delivered with the Measurement Control message.

Transition from the CELL_FACH to the CELL_DCH sub-state.

In the CELL_FACH sub-state, the SIB 12 (or SIB 11, if there is no SIB 12) is valid including all relevant

measurement control parameters. If the UE transits to the CELL_DCH sub-state, the system

information stays valid, as long as there was no Measurement Control message, which replaces the

parameters.

But what happens, if the UE was in the CELL_DCH sub-state, it has received Measurement Control

messages, and it then transits to the CELL_FACH sub-state. In the CELL_FACH sub-state, the UE

reads SIB 12 (SIB 11), and its measurement control parameters become valid. But when the UE thentransits back to the CELL_DCH sub-state, the UE resumes with the measurements and associated

reporting, as they were stored before the transition to the CELL_FACH (or any other RRC connected)

sub-state.


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The RRC message Measurement Control is used to setup, to modify, and to release a measurement in the UE.

The UE gets all relevant information, how to perform a specific type of measurements.A measurement is

either conducted periodically or driven by an event. Then, the UE returns a measurement report.

The Measurement Control message is transmitted on a DCCH via an RLC entity in the acknowledged mode.

I.e. the UE is either in the RRC connected sub-state CELL_DCH or CELL_FACH.

If the setup of a measurement fails, the UE returns the RRC message Measurement Control Failure. It is

transmitted on an UL DCCH via an RLC entity in the acknowledged mode.

The RRC message Measurement Report was specified to deliver measurement results from the UE to UTRAN

(RNC). This message is transmitted on a DCCH. The RLC entity can be in the acknowledged or

unacknowledged mode. The RLC entity mode is set by the RRC message Measurement Control.

Measurement results can be only transmitted in the CELL_DCH or CELL_FACH sub-state.CELL_DCH: If a reporting criterion is met, the UE transmits a Measurement Report. A measurement identity

identifies the measurement as specified by UTRAN. It includes measurement quantities and identifies the

measurement event.

CELL_FACH: In this sub-state, traffic volume measurements and positioning measurements are reported by

the UE. Intra-frequency measurements are reported via the RACH, whereby the UE learns from the BCCH

(SIB11 or SIB12) the maximum numbers of cells, it can report.

CELL_PCH or URA_PCH: UE must perform a cell update. Cell update cause is uplink data transmission.

Then they are in the CELL_FACH state, where the Measurement Report can be sent. The measurement report

either holds traffic volume measurements or positioning measurements.


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With the RRC message Measurement Control, UTRAN commands the UE to perform measurements on

its behalf. There is a set of different types of measurements, which can be conducted:

Intra-Frequency Measurements

Inter-Frequency Measurements Inter-RAT Measurements UE-Internal Measurements Traffic Volume Measurements Quality Measurements UE Positioning MethodsAs a consequence, a UE may be forced to conduct several different types of measurementssimultaneously. Each type of measurement is identified by an allocated Measurement Identity.

Some measurements are not conducted continuously. UTRAN tells the UE once, how to perform a typeof measurements. Whenever necessary, it just informs the UE to conduct the measurements of ameasurement type by just telling it the associated measurement identity.

Each measurement type comes with a measurement command: setup, modify, and release.

Finally, UTRAN inform the UE, how to deliver the measurement reports:

Delivery on an acknowledged or unacknowledged RLC, andPeriodical or event triggered reporting.

In the RRC message Measurement Control, the is an PhyCH information elements, where the UE cangain DPCH compressed mode status information.


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UE IEs

Measurement IEs

PhyCH IEs

Measurement Identity

Measurement Command

Measurement Reporting Mode

CHOICE Measurement ty pe

Additional measurements list

DPCH compressed mode

status info

setup/modify/release

RLC AM/UM and

periodical reporting/event triggeredincludes non-frequencyrelated cell info

Intra-Frequency MeasurementsInter-Frequency MeasurementsInter-RAT Measurements

UE-Internal MeasurementsTraffic Volume MeasurementsQuality MeasurementsUE Positioning Methods

UERNC

Measurement Control ( )

RRC messages information


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UL Traffic volumes High threshold information sent after RAB setup complete (CELL_DCH)



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UE Buffer triggers Threshold for RAB Upgrade



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First RAB Reconfiguration

DL 32Kbps(SF64)/ UL 32Kbps SF32)



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UL Traffic volumes High threshold information sent after RAB setup complete (CELL_DCH)



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Second RAB Reconfiguration

DL 384Kbps(SF8)/ UL 32Kbps (SF32)

Maximum DL bit rate for PS domain NRT data = 384 Kbps

Maximum UL bit rate for PS domain NRT data = 64 Kbps

Initial and minimum allowed bit rate in downlink = 32 Kbps

Initial and minimum allowed bit rate in uplink = 32 Kbps



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Cell DCH Cell FACH



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Cell FACH Cell PCH



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Cell PCH Cell FACH



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Cell FACH Cell DCH

Intra-frequency Measurements


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Intra-frequency measurements are measurements on downlink physical channels at the same frequency as

the active set. The measurement object is one cell.

If the RRC message Measurement Control commands the UE to make intra-frequency measurement, it may

contain among others:

Intra-frequency cell info list (optional)Measurement quantity

There are three different measurement quantities for the FDD mode:

- Downlink Ec/N0

- Downlink received signal code power (RSCP) after despreading.

- Downlink pathloss in dB = Primary CPICH Tx power - CPICH RSCP.

Measurement validity

The measurement validity describes, when the measurement has to be conducted. There are three options:- CELL_DCH state,

- all states except the CELL_DCH state, and

- all states.

Reporting Criteria

Reporting criteria outline, what kind of intra-frequency measurements have to be conducted. A set of intra-

frequency measurements were specified, but it is the operators choice, which ones are used.

Intra-frequency Reporting Events


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Below, you can see a list of intra-frequency reporting events. UTRAN decides, which of the listed events have to be

reported by the UE. The required intra-frequency reporting events, which are choosen by UTRAN, depend on the

implemented handover reporting function or other radio network functions. The measurement quantities are

determined by measuring the P-CPICH of the cell.

Reporting events

1A: A Primary CPICH enters the reporting range

The reporting range can be between 0 and 14.5 dB (step size 0.5 dB). The reporting range can be set in relation with

the measurement of the best (strongest) cell as is was displayed on the next figure. It can be also set in ration with

a weighted average of the best measured cell and the averaged measurement results of additional, non-forbidden

cells. If a CPICH crosses the reporting range, a reporting event is triggered. A individual cell offset can be taken into

account.

1B: A primary CPICH leaves the reporting rang Similar concept as in 1A.1C: A non-active primary CPICH becomes better than an active primary CPICH

1D: Change of best cell

1E: A Primary CPICH becomes better than an absolute threshold (RAN 1.5)

1F: A Primary CPICH becomes worse than an absolute threshold (RAN 1.5)

A hysteresis value can be set before reporting the event in all reporting events in the figures, this is only shown for 1A

and 1B.

Inter-rat



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1E for

cell 3

Reporting event: 1E:A P-CPICH becomes better than

an absolute threshold

1F:A P-CPICH becomes worse than

an absolute threshold

1F

for

cell 1

time

Cell 1 Cell 2

Cell 3

absolute

threshold

e

.g.

P-CPICHE

c/No

Neighbourhood List Combination for Intra-frequency HOs


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Cell 5 Cell 6 Cell 7 Cell 8



Cell 3

Cell11

Neighbour cells which

are common to Cell 6and Cell 7

Cell 4

Cell 8

Cell 12

Cell 6

Neighbour cells

defined only for Cell 7

Cell 2

Cell7

Cell 10

Cell 5

Neighbour cells

defined only for Cell 6

Two Cells in theActive Set

Neighbourhood List Combination for Intra-frequency HOs


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Cell 2

Cell 5

Cell 7

Cell 9

Cell 11

Cell 15

Cell 48

Cell 4

Cell 41Cell 6

..

...

Cell 43

Cell 15

Cell 21

Cell 2Cell 7

Cell 37

Cell 51

Cell 49

Cell 9

Cell 10Cell 56

...

Cell 25

Cell 1

Cell 2

Cell 3Cell 7

Cell 11

Cell 50

Cell 9

Cell 13

Cell 10

Cell 22

...

Cell 33

Neighbour Cells ListsStep 1

Three Cells in theActive Set

Cell2

Cell 7

Cell 9

Common to 3

Neighbour Lists

Step 2

Cell 11

Cell 15

Cell 10

Cell 37

Cell 41

Cell 49

..

Cell 22

Max 32

Cells

Neighbour Cells definedfor only 1 Neighbour List:

random selectionStep 4

Common to 2

Neighbour Lists

Step 3

CS and PS Call Flow


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When a UE is switched on, it starts to monitor the radio interface to find a suitable cell to camp on. But

it has to determine, whether there is a WCDMA cell nearby. If a WCDMA cell is available, the UEhas to be synchronised to the downlink transmission of the system information transmitted on the

physical channel P-CCPCH before it can make a decision, in how far the available cell is suitable

to camp on. Initial cell selection is not the only reason, why a UE wants to perform cell

synchronisation. This process is also required for cell re-selection and the handover procedure.

Cell synchronisation is achieved with the Synchronisation Channel (SCH). This channel divides up

into two sub-channels: P-SCH and S-SCH

With the help of the SCH, the UE was capable to perform chip, TS, and frame synchronisation. Even

the cells scrambling code group is known to the UE.

The UE knows the cells primary scrambling code. It now wants to gain the cell system information,

which is transmitted on the physical channel P-CCPCH. The channelisation code of the P-CCPCH

is also known to the UE, because it must be Cch,256,1 in every cell for every operator. By reading the

cell system information on the P-CCPCH, the UE learns everything about the configuration of the

remaining common physical channels in the cell, such as the physical channels for paging and

random access.

Cell Search

RAB 1st

then RRC

UE RNCNodeB MGW/CNMOS CS Message Flow


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RRC: RRC Connection Request (RACH)

NBAP: Radio Link Setup Request

NBAP: Radio Link Setup Response

ALCAP: ERQ (Establish Request)

ALCAP: ECF (Establish Confirm)

RRC: RRC Connection Setup (FACH) [RRCconnRepTimer1/2(100ms,1s)]

L1 Synchronization

NBAP: Synchronization Indication

RRC: RRC Connection Setup Complete (DCH)

RRC: Initial Direct Transfer (MM: CM Service Request)

SCCP: CR (Connection Request)

RANAP: Initial UE Message (MM: CM Service Request)

SCCP: CC (Connection Confirm)

RANAP: Direct Transfer (MM: Authentication Request)

RRC: Downlink Direct Transfer (MM: Authentication Request)

RRC: Uplink Direct Transfer (MM: Authentication Response)

RANAP: Direct Transfer (MM: Authentication Response)

RANAP: Common ID

RANAP: Security Mode Command

RRC: Security Mode Command

FP: Downlink Synch

FP: Uplink Synch

RRC Connection Establishment CELL DCH State

RNC checks if resources areavailable: BTS, AC,Transmission.

If not it sends RRC ConnectionReject

T300=2s ; N300=3

L1 Synchronization

T312=6s ; N312=4

RRC Connection

till the RNC

UE RNCNodeB MGW/CN

RRC S it M d C l t


87/192

RRC: Security Mode Complete

RANAP: Security Mode Complete

RRC: Uplink Direct Transfer (CC: Setup)RANAP: Direct Transfer (CC: Setup)

RANAP: Direct Transfer (CC: Call Confirmed)RRC: Downlink Direct Transfer (CC: Call Confirmed)

RANAP: RAB Assignment Request

NBAP: Radio Link Reconfiguration Prepare

NBAP: Radio Link Reconfiguration Ready



NBAP: Radio Link Reconfiguration Commit)

RRC: Radio Bearer Setup

RRC: Radio Bearer Setup Complete

RANAP: RAB Assignment Response



RAB Establishment

FP: Downlink Synch

FP: Uplink Synch

RL modification procedure:

SRB+DCH, HW resources checked

Possible failure in AAL2 setup

(Iub, Iur and Iu)

Soft handover is not allowed during the RAB establishment procedure (The mobile can not add or remove cells in AS) this makes the

UE and Node B particularly sensitive to mobility and dominance Timer wf_rb_setup_cpl (6s) is started when the RRC: Radio Bearer

Setup message is sent to the UE In case the timer expires Iu Release Request is sent to the CN with release cause (radio_conn_lost)

UE RNCNodeB

RANAP: Direct Transfer (CC: Connect)

MGW/CNRANAP: Direct Transfer (CC: Alerting)

RRC: Downlink Direct Transfer (CC: Alerting)


88/192

Call Established

RANAP: Direct Transfer (CC: Connect)RRC: Downlink Direct Transfer (CC: Connect)

RRC: Uplink Direct Transfer (CC: Connect Acknowledge)

RANAP: Direct Transfer (CC: Connect Acknowledge)

RRC: Uplink Direct Transfer (CC: RRC Connection Release Complete)

RANAP: Direct Transfer (CC: Release Complete)

RANAP: Iu Release Command

RRC: Uplink Direct Transfer (CC: Disconnect)

RANAP: Direct Transfer (CC: Disconnect)

RANAP: Direct Transfer (CC: Release)

RRC: Downlink Direct Transfer (CC: Release)

RANAP: Iu Release Complete

RANAP: Location ReportRRC: Measurement Control

Call Disconnect

RRC: Downlink Direct Transfer (CC: RRC Connection Release)



NBAP: Radio Link Deletion Request

NBAP: Radio Link Deletion Response



UE RNCNodeB MGW/CNMTC CS Message Flow

RANAP: Paging


89/192






RRC: RRC Connection Setup (FACH)

L1 Synchronization



RRC: Initial Direct Transfer (MM: Paging Response)

SCCP: CR (Connection Request)

RANAP: Initial UE Message (MM: Paging Response)

SCCP: CC (Connection Confirm)

RANAP: Direct Transfer (MM: Authentication Request)

RRC: Downlink Direct Transfer (MM: Authentication Request)

RRC: Uplink Direct Transfer (MM: Authentication Response)

RANAP: Direct Transfer (MM: Authentication Response)

RANAP: Common ID

RANAP: Security Mode CommandRRC: Security Mode Command

FP: Downlink Synch

FP: Uplink Synch


L1 Synchronization

RANAP: PagingRRC: Paging Type 1

UE RNCNodeB MGW/CN



90/192



RRC: Uplink Direct Transfer (CC: Setup)RANAP: Direct Transfer (CC: Setup)

RANAP: Direct Transfer (CC: Call Confirmed)RRC: Downlink Direct Transfer (CC: Call Confirmed)






NBAP: Radio Link Reconfiguration Commit)


RRC: Radio Bearer Setup Complete

RANAP: RAB Assignment Response



RAB Establishment

FP: Downlink Synch

FP: Uplink Synch



Possible failure in AAL2 setup

(Iub, Iur and Iu)

Soft handover is not allowed during the RAB establishment procedure (The mobile can not add or remove cells in AS) this makes the

UE and Node B particularly sensitive to mobility and dominance Timer wf_rb_setup_cpl (6s) is started when the RRC: Radio Bearer

Setup message is sent to the UE In case the timer expires Iu Release Request is sent to the CN with release cause (radio_conn_lost)

UE RNCNodeB MGW/CN

RANAP Di t T f (CC Al ti )RRC: Downlink Direct Transfer (CC: Alerting)


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Call Established

RANAP: Direct Transfer (CC: Connect)RRC: Downlink Direct Transfer (CC: Connect)

RRC: Uplink Direct Transfer (CC: Connect Acknowledge)

RANAP: Direct Transfer (CC: Connect Acknowledge)

RANAP: Location ReportRRC: Measurement Control

RANAP: Direct Transfer (CC: Alerting)

UE NodeB RNC SGSNMOS PS Message Flow



92/192



AAL2SIG: ERQ

AAL2SIG: ECF


RRC: Initial Direct Transfer (MM: Attach Request)

RANAP: Initial UE Message MM: (Attach Request)

RANAP: Direct Transfer (MM: GPRS Identity Request)RRC: Downlink Direct Transfer (MM: GPRS Identity Request)

RRC: Uplink Direct Transfer (MM: GPRS Identity Response)RANAP: Direct Transfer (MM: GPRS Identity Response)

RANAP: Direct Transfer (MM: Authentication & CipheringRequest)

RRC: Downlink Direct Transfer (MM: Authentication & Ciphering Request)

RRC: Uplink Direct Transfer (MM: Authentication & Ciphering Response)

RANAP: Direct Transfer (MM: Authentication & CipheringResponse)

RANAP: Security Mode CommandRRC: Security Mode Command



RANAP: Common ID

L1 Synchronization


FP: Downlink SynchFP: Uplink Synch



RRC: RRC Connection Setup (FACH) [RRCconnRepTimer1/2(100ms,1s)]

RNC checks if resources areavailable: BTS, AC,Transmission.If not it sends RRC ConnectionReject

L1 Synchronization

RANAP: Direct Transfer (MM: Attach Accept)

UE NodeB RNC SGSNMOS PS Message Flow


93/192

RANAP: Direct Transfer (MM: Attach Accept)RRC: Downlink Direct Transfer (MM: Attach Accept)

RRC: Uplink Direct Transfer (MM: Attach Complete)

RANAP: Direct Transfer (MM: Attach Complete)

RRC: Uplink Direct Transfer (SM: Activate PDP Context Request)

RANAP: Direct Transfer(SM: Activate PDP Context Request)

NBAP: Radio Link Reconfiguration Commit

RRC: Radio Bearer Reconfiguration

RRC: Radio Bearer Reconfiguration Complete




RRC: Radio Bearer Setup CompleteRANAP: RAB Assignment Response

RANAP: Direct Transfer(SM: Activate PDP Context Accept)

RRC: Downlink Direct Transfer (SM: Activate PDP Context Accept)


RRC: Measurement Control

RRC: Measurement Repor (Trafic Volume Reports 4a)

AAL2SIG: ERQ

AAL2SIG: ECF

RAB EstablishmentSRB + DCH 0/0



Uplink & Downlink Data Transfer

UE NodeB RNC SGSN

MOS PS Message Flow


94/192

RRC: Uplink Direct Transfer (SM: Deactivate PDP Context Request)

RANAP: Direct Transfer (SM: DeactivatePDP Context Request)RANAP: Direct Transfer(SM: Deactivate PDP Context Accept)

RRC: Downlink Direct Transfer (SM: Deactivate PDP Context Accept)

NBAP: Radio Link Reconfiguration Commit



AAL2SIG: ERQ

AAL2SIG: ECF

RRC: Radio Bearer Release

RRC: Uplink Direct Transfer (MM: Detach Request) RANAP: Direct Transfer (MM: Detach Request)

RANAP: Direct Transfer (MM: Detach Accept)

RRC: Downlink Direct Transfer (MM: Detach Accept)

RANAP: Iu Release Command

RANAP: Iu Release Complete

RRC: Radio Bearer Release Complete

RRC: RRC Connection ReleaseRRC: RRC Connection Release Complete

NBAP: Radio Link Deletion Request

NBAP: Radio Link Deletion Response

AAL2SIG: REL (Release Request)

AAL2SIG: RCL (Release Confirm)

RRC: RRC Connection Release Complete

RRC: RRC Connection Release Complete


95/192


96/192


97/192


98/192

Real

traffictransfer

Bearer

setupRRCsetup


99/192


100/192

9:52:53 : C09 AMR


101/192

9:52:53 : C09 AMR


102/192


103/192


104/192


105/192


106/192


107/192


108/192


109/192


110/192


111/192

Soft Handover


112/192

Handover Types


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121 2006 Nokia

Intra-Frequency Handovers

Softer Handover

Handover between sectors of the same Node B (handled by BTS)

No extra transmissions across Iub interface Maximum Ratio Combining (MRC) is occurring in both the UL and DL

Soft Handover

MS simultaneously connected to multiple cells (from different Node Bs) Extra transmission across Iub, more channel cards are needed (compared to non-SHO) Mobile Evaluated Handover (MEHO) DL/UE: MRC & UL/RNC: Frame selection combining

Hard Handover Arises when inter-RNC SHO is not possible (Iur not supported or Iur congestion) Decision procedure is the same as SHO (MEHO and RNC controlled) Causes temporary disconnection of the (RT) user

Inter-Frequency Handover

Can be intra-BS, intra-RNC, inter-RNC

Network Evaluated Handover (NEHO)

Decision algorithm located in RNC

Inter-RAT Handover

Handovers between GSM and WCDMA (NEHO)

SHO: Neighbour Cell Definition


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Each intra-frequency neighbour (ADJS) is identified using ADJSid(ADJS)

The ADJS parameters provide information on the identity of each neighbour cell together

with its properties (i.e. Handover parameter set identifier, scrambling code etc..)

Each neighbour cell is defined using the UTRAN cell identifier which comprises

UTRAN Cell Identifier = MCC + MNC + RNC identifier + Cell identifier

Each neighbor cell is defined using the UTRAN cell identifier which comprises;

MCC (Mobile Country Code) = AdjsMCC

MNC (Mobile Network Code) = AdjsMNC

RNC Identifier = AdjsRNCid

Cell Identifier = AdjsCI

The LAC (Ad jsLAC) & RAC (AdjsRAC) are also in ADJS parameter set

ADJS Parameters

Maximum number of neighbours


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125 2006 Nokia

The maximum number of neighbours that can be defined in RNCdatabase is

ADJS: 31

31 neighbours + serving cell = 32 cells to measure

ADJI: 32/carrier, total 48

ADJG: 32

Total: max. 111 in RNC database

Limitation due to specifications of SIB11/12 size

Soft Handover


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127 2006 Nokia

HC supports the following measurement reporting events and

features: Event 1A: A primary CPICH enters the reporting range (Ncell addition)

Event 1B: A primary CPICH leaves the reporting range (Ncell deletion)

Event 1C: A non-active CPICH becomes better than an active primaryCPICH (Ncell replacement)

Cell individual offsets for modifying measurement reporting behaviour

Mechanism for forbidding a neighbor ing cell to affect the reportingrange

Handover decision performed by RNC based on measurements andavailable resources

Admission Control can reject the branch addition in case the

maximum load is achieved in DL (threshold + offset), valid both forRT and NRT bitrates.

Hard blocking may prevent branch addition

1A: A Primary CPICH Enters the Reporting Range


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130 2006 Nokia

Strongest CPICH in AS

time

Ec/Io

P CPICH 3

P CPICH 1

P CPICH 2

1

2

Addi t ionWindo

w

Addi t ionT ime

Addi t ionReport ingInterval

RNC

MeasurementReport

Add tothe AS?

no

Act iveSetWeight ingCoeff ic ient

34

1B: A Primary CPICH leaves the Reporting Range


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133 2006 Nokia

Strongest CPICH in AS

time

Ec/Io

P CPICH 3

P CPICH 1

P CPICH 2

1

2

3

DropWindow

DropTime

MeasurementReport

Remove thereported cellfrom the AS

Extract from SIB 11S 11

Soft and Softer Handover (case1)


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135 2006 Nokia

reportCriteria intraFreqReportingCriteria : {eventCriteriaList {{event e1a : {

triggeringConditionmonitoredSetCellsOnly,

reportingRange 4,w 0,reportDeactivationThreshold t2,reportingAmount ra-Infinity,reportingInterval ri0-5},

hysteresis 0,timeToTrigger ttt100,reportingCellStatus

allActiveplusMonitoredSet :viactCellsPlus2

}event e1b : {

triggeringCondition

activeSetCellsOnly,reportingRange 6,w 0},hysteresis 0,timeToTrigger ttt640,reportingCellStatus withinActiveSet :

e3},

SIB 11 contains the relevant

parameters to read when in idle mode

These are valid in connected modeprior to receiving the measurement

control that overwrites them

In this example:

Addition window= 2 dB (factor of 2

mapping between the signalled value and

the actual value, TS 25.331 defines thismapping)

Addition time = 100 ms

Reporting interval = 500 ms

Drop window = 3 dB (factor of 2 mapping

between the signalled value and theactual value)

Drop time = 640 ms

1C: A non-active CPICH becomes better than an active primary

CPICH


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137 2006 Nokia

time

weakest CPICH3 in AS

Ec/Io

P CPICH 3

P CPICH 1

P CPICH 2P CPICH 4

AS has 3 cells

ReplacementReport ingInterval3

1

2

ReplacementWindow

ReplacementTime

MeasurementReport

RNC

ASupdate?

no

Soft and Softer Handover (case 2)


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138 2006 Nokia

event e1c : {replacementActivationThreshold

t3,reportingAmount ra-Infinity,reportingInterval ri0-5},hysteresis 4,timeToTrigger ttt100,reportingCellStatus

withinActiveSet : e3}

Extract from SIB 11 cont.

In this example: Replacement window = 1 dB

Replacement time = 100 ms

Reporting interval = 500 ms

Replacement window requires mapping to its truevalue according to:

4/(2*2) = 1 dB

There are two mappings first is the signalled value to actual value mapping andsecond is the way in which hysteresis is applied in the event triggering equation(TS25.331)

Once in connected mode the networks sends the same set of information elementsvia a measurement control message

Nokias implementation is that the values in the measurement control message arethe same as those within SIB 11

Events 6F and 6G are configured in a similar fashion i.e. within SIB 11 andsubsequently with a measurement control message

Individual Ncell Offset


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140 2006 Nokia

time

P CPICH 1

P CPICH 2

P CPICH 3

Reporting Range

ReportingEvent 1B

ReportingEvent 1A

AdjsEcNoOffset

Enlarging Cell 3 by xdB

Ec/Io

Forbidding Neighbour Cell from Reporting Range


123/192

141 2006 Nokia

Time

P CPICH 1

P CPICH 2

P CPICH 3

PCPICH3 is forbiddento affect the reportingrange as its quality is

quite unstable.

Reporting

Range

AdjsDERR

Ec/Io

Soft Handover signalling


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142 2006 Nokia

Branch addition

RRC: Measurement Report (e1a)

RRC: Active Set Update

RRC: Active Set Update Complete

RRC: Measurement Report (e1b)

RRC: Active Set Update

RRC: Active Set Update Complete

Branch deletion

SHO Summary


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143 2006 Nokia

Event 1A(Add)

Event 1B(Drop)

Event 1C(Replace)

Active set cells +2 monitored set

cells

Monitored setcells

AdditionWindow/4 dB

Active set cells Active set cellsDrop Window/

6 dB

Active set cells +2 monitored set

cells-

ReplacementWindow/2 dB

Addition Time/100 ms

AdditionReporting

Interval

/0.5 s

Drop time/640 ms

-

Replacementtime/100 ms

ReplacementReportingInterval/

0.5s

EventReporting cell

statusTriggeringCondition

Reporting Range/Hysteresis

Time to TriggerReporting

Interval

3GPP reporting events 1A, 1B and 1C (also 6F and 6G)

CPICH Ec/Io is used as a measurement quantity rather than CPICH RSCP CPICH Ec/Io measurements are more accurate

1A and 1B reporting range is defined by strongest active set cell

1C reporting range is defined by weakest active set cell

RRC Connection Release


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144 2006 Nokia

If difference between the best AS cell and the NS cell is too high and SHO is notperformed, the RRC connection is released to avoid excessive interference

Why might an AS update not be possible?

Excessive load in the neighbor ing cell

Hard blocking in the target BTS

Unavailability of DL spreading codes

Iub transport resources unavailable

This function is activated by EnableRRCRelease(HOPS parameter)/0=no (def),1=yes

The RRC connection is released if either:

AveEcNoDownlink + ReleaseMarginForAveEcNo(n) < AvEcNoNcell(n)

EcNoDownlink + ReleaseMarginPeakEcNo(n) < EcNoNcell(n)

ReleaseMarginForAveEcNo(HOPS) = average Eb/N0 margin [-6 6] dB, default 2.5dB

ReleaseMarginPeakEcNo(HOPS) = peak Eb/N0 margin [-6 6] dB, default 3.5dB

Emergency calls are exempt from RRC Connection Release process

Inter-RNC Mobility


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145 2006 Nokia

Most of the times the UE hands over among WBTS belonging to the same RNC(Intra-RNC Handovers)

However, what happens when the target WBTS is under a different WBTS?? 3GPP gives two different options to handle inter-RNC mobility in WCDMA

Anchoring: the UE will be connected to the CN via the old RNC. It is required Iurconnection between the RNCs involved

SRNS relocation: the UE will be connected to the CN via the new RNC. It is the Nokiaimplemented method

*) SRNS relocation needs core networksupport; UE support mandatory in 3GPP

CN

RNCRNC

Iu Iu

Iur

CN

RNCRNC

Iu Iu

Iur

AnchoringCN

RNCRNC

Iu Iu

Iur

CN

RNCRNC

Iu Iu

Iur

SRNS relocation *)

UE not involved SRNC Relocation for RT

UETarget RNCCNS RNC SRNC Relocation is initiated in the Serving RNCRelocationSupport =1NrncRelocationSupport=1


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146 2006 Nokia

UETarget RNC

SRNC Relocation Decision

SRNC operationstarted

CN

UP switching

User plane set-up

RANAP:Relocation Required

RANAP:Relocation Request

RANAP:Relocation Request Ack

RANAP:Relocation complete

RRC:UTRAN Mobility Information

RANAP:Relocation Command

RNSAP:Relocation Commit

RANAP:Relocation Detect

RRC:UTRAN Mobility Information Confirm

RANAP:Iu Release

RANAP:Iu Release Complete

User plane release

Source RNC SRNC Relocation is initiated in the Serving RNCwhen all the cells of the active set belong to adifferent RNC. The SRNC sends a RelocationRequired

The CN evaluates if the relocation is possible andin that case, it sends a Relocation Request to thetarget RNC with parameters for the bearerestablishment

Relocation Command sent from CN to SourceRNC with UTRAN information and bearerparameters

After that, the Source RNC sends RelocationCommitmessage over Iur to the Target RNC

When target RNC starts to act as Serving RNC, itsends a Relocation Detectmessage to CN. Thismessage has no parameters

At the same time UTRAN Mobility Information issent to the UE, to inform that the relocation isperformed

After the confirm, the target RNC informs CNwith Relocation Completemessage that therelocation procedure was successful and Iu isreleased from source RNC

Start RelocPrep

Stop RelocPrep

Start RelocOverall

Start RelocOverall

Stop RelocOverall

Stop RelocOverall

UE involved: Combined SRNC Relocation and inter-RNC HHO for RT

UETarget RNCCNSource RNC

RelocationSupport =1NrncRelocationSupport=1


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147 2006 Nokia

UETarget RNC

SRNC Relocation Decision

L1 sync. Establishedbetween BTS andUE

CN

UP switching

User plane set-up

RANAP:Relocation Required

RANAP:Relocation Request

RANAP:Relocation Request Ack

RANAP:Relocation complete

Physical Ch Reconfig Complete

RANAP:Relocation Command

Physical Channel Reconfiguration

RANAP:Relocation Detect

RANAP:Iu Release

RANAP:Iu Release Complete

User plane release

Source RNC

Because there is no Iur interface, combined SRNS

relocation and HHO are done before the UE is

completely under the target RNC

The procedure is quite similar to the not UE

involved case until Relocation Command

The only difference in the Relocation Required

message, the Relocation Type IE is set to "UE

involved in relocation of SRNS"

Instead of Relocation Commit via Iur, the serving

RNC sends a Physical CH Reconfiguration, after

which the UE stops transmitting and receiving on

the old radio links and starts on the new radio link

Start RelocPrep

Stop RelocPrep

Start RelocOverall

Stop RelocOverall

Start RelocOverall

Stop RelocOverall

Inter-system Handover (ISHO)


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Inter system Handover (ISHO)

ISHO

Inter System Handover 3G -> 2G

General


131/192

Downlink DPCH powerUL Quality

deteriorationUE Tx power CPICH RSCP CPICH Ec/I0

RAN Internal measurements Configured UE measurements

Initiate Compressed Mode

Configure GSM measurements

UE Reports

GSM RSSI measurements

GSM Cell

Meets HO condition ?

Initiate Handover

Initiate Compressed Mode

Configure GSM measurementsPS

CS

UE Reports

GSM BSIC measurements

DL DPCH power

CPICH RSCP (Event 1F)Thresholds:

CPICH Ec/Io (Event 1F)Thresholds:

ISHO parameters


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150 2006 Nokia

Decision Algorithm

UE Tx Power (Event 6A)Threshold:GsmUETxPwrThrXXL3 filter:GsmUETxPwrFilterCoeffHysteresis margin:GsmUETxPwrTimeHystData rate thresholdHHOMAxAllowedBitrateUL

UL QualityTimer:ULQualDetRepThresholdData rate thresholdHHOMAxAllowedBitrateUL

DL DPCH powerThreshold:GsmDLTxPwrThrXX

Data rate thresholdHHOMAxAllowedBitrateDL

(XX=AMR,CS,NrtPS,RtPS)

Thresholds:HHoRscpThresholdHHoRscpCancelL3 filter:HHoRscpFilterCoefficientTimers:

HHoRscpTimeHysteresisHHoRscpCancelTime

Thresholds:HHoEcNoThresholdHHoEcNoCancelL3 filter:Done already for SHOTimers:

HHoEcNoTimeHysteresisHHoEcNoCancelTime

AdjgTxPwrMaxTCHAdjgRxLevMinHO (n)GsmMeasAveWindow

GsmMeasRepIntervalGsmNcellSearchPeriodGsmMinMeasIntervalGsmMaxMeasPeriod

Handover Triggering

Handover Execution

2G-to-3G back prevention

GsmMinHoInterval

GSM measurement reporting

2 more optional triggers in RAN04:

IMSI based ISHOEmergency ISHO (EMISHO)

Measurement Control Parameters: FMCG

Maximum allowed duration of the inter system measurement is calculated:


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151 2006 Nokia

Maximum allowed duration of the inter-system measurement is calculated:

GSMMeasRepInterval* GSMMaxMeasPeriod (=0.5*20s) =10s,

This seems to be too long time, because based on field measurementsBSIC and RSSI delays are about 3 seconds, so it makes senses to reducethe value of this parameter to some value about 3 seconds, otherwise, if theBSIC or RSSI measurements fail or if the IS-HO execution is not possible todue low GSM RSSI levels, the network will not deactivate compressedmode until the timer of 10 seconds has expired. Thus, decreasing theparameter value will allow the UE/network to initiate a new IS-HO attempt.

Proposed value forGSMMaxMeasPeriodis 6 GSMNcellSearchPeriod: 0

This is neighbor cell search period parameter, ISHO is not allowed until the areenough measurement reports given by this parameter

O means that only 1 measurement result is enough for decision making

Duration of the cell search period is calculated:

GSMRepInterval* GSMNcellSearchPeriod).

ISHO Process Overview


134/192

HO Triggering Thresholds set in RNC

Event Triggered Coverage/Capacity

based HO fulfilled in RNC

RNC commands selected UE(s) to start

IF/IS measurements

Measurements are done in

Compressed Mode (CM)

UE reports GSM cells with

strongest RSSI signals to RNC

RNC makes HO decision and

commands UE to target cell

RSSI measurements and BSICverification for GSM cells

Different decision methods for IF HO

Only one decision method for IS HO

5 Coverage/Capacity HO Reasons

About 25 HO parameters

Reporting cells are active set cells(max 3) + max 6 IFHO, max 6 ISHO neighb.

Max 32 neighbours could be measured

(31 Intra-Freq neighbours)

48 Inter-Freq neighbours

32 Inter-System neighbours can be measured

CNU Node RNC

ISHO 3G -> 2G - AMR Signalling Flow


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153 2006 Nokia

BSIC verification always performed for AMR calls no interrupt in voice call

E B

RRC: Measurement Report

RRC: MeasurementControl

NBAP: Radio Link ReconfigurationPrepare

NBAP: Radio Link ReconfigurationReady

NBAP: Radio Link ReconfigurationCommitRRC: Physical Channel

ReconfigurationRRC: Physical Channel ReconfigurationComplete

NBAP: Compressed ModeCommand


RRC: Measurement

Control

NBAP: Compressed ModeCommand



RRC: Handover from UTRAN

Command

GSM BSICIdentification

GSM RSSIMeasurement

ISHO triggering(2 reasons are

possible)

InitialCompressedModeConfiguration

RANAP: RelocationRequired

RANAP: RelocationCommand

RANAP: IU ReleaseCommand

RANAP: IU ReleaseComplete

UE

NodeB

RNC

CN

ISHO 3G -> 2G - PS Signalling Flow


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154 2006 Nokia

In most cases BSIC verification is not required (data interrupt as UE moves to2G)

PS makes use of RRC: CELL CHANGE ORDER FROM UTRAN message

E BRRC: Measurement Report


NBAP: Radio Link ReconfigurationPrepareNBAP: Radio Link ReconfigurationReady

NBAP: Radio Link ReconfigurationCommit

RRC: Physical Channel Reconfiguration

RRC: Physical Channel ReconfigurationComplete

NBAP: Compressed Mode Command



GSM RSSI Measurement

ISHO triggering (5 reasons arepossible)

Initial CompressedMode Configuration

RANAP: SRNS ContextRequest

RANAP: SRNS ContextResponse

RANAP: IU ReleaseCommand

RANAP: IU ReleaseComplete

RRC: Cell Change Order fromUTRAN

RANAP: SRNS Data ForwardCommand


137/192

3G -> 2G Handover measurement triggering

IS Handover Triggering Reasons


138/192

1. DL DPCH approaches its

maximum allowed power

FMCI:IFHOcauseTxPwrDL

FMCG:GSMcauseTxPwrDL

2. Quality deterioration report

from UL outer loop PC

FMCI: IFHOcauseUplinkQuality

FMCG: GSMcauseUplinkQuality

4. UE Tx power approaches its

maximum allowed power, event 6A/6D

FMCI: IFHOcauseTxPwrUL

FMCG: GSMcauseTxPwrUL

5 . Low measured absolute

CPICH RSCP, events 1E/1F

FMCI:IFHOcauseCPICHrscp,

FMCG:GSMcauseCPICHrscp

3. Low measured absolute

CPICH Ec/No, event 1E/1F

FMCI:IFHOcauseCPICHEcNo

FMCG:GSMcauseCPICHEcNo

HO trigger

6 . Others (Not implemented in RAN 1.5):

e.g. Traffic & load reason IS-HO, etc

Frequency Measuring Control for Inter-Frequency = FMCI

Frequency Measuring Control for Inter-System (GSM) = FMCG

Measurement triggering: CPICH Ec/No

Reporting event: 1E: A P-CPICH exceeds an absolute threshold (triggered


139/192

if one) 1F: A P-CPICH falls below an absolute threshold

(triggered if all)

e.g.

P-CPICHE

c/

No

time

Cell 1 Cell 2

Cell 3

absolute

threshold

1E: HHoEcNoCancel

1E: HHoEcNoCancelTime

1F: HHoEcNoThreshold

1F: HHoEcNoTimeHysteresis


RNC starts IF/IS measurement when event 1F occurs for all cells in the


140/192

active set: A Primary CPICH becomes less than an absolute threshold

RNC stops IF/IS measurement when event 1E occurs for at least one cell of

the active set : A Primary CPICH becomes better than an absolute

threshold

Note:IF/IS measurements can be stopped ifevent 1Fs are cancelled by

events 1E only when IFHO/ISHO was not successful and only inside the

time between CM measurements, specified by the

time InterFreqMinMeasInterval ,GsmMinMeasInterval/default 10s,

recommendation 2s .

Filtering applied before event evaluation in the UE:

FMCS: EcNoFilterCoefficient/0= 200ms filtering period


Event 1E parameters:


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p

Triggering conditions: Active set cells

Hysteresis: not used in 1F

Threshold used frequency: FMCS : HHoEcNoCancel/ -9dB Time-to-trigger: FMCS: HHoEcNoCancelTime/ 1280 ms

Amount of reporting: infinity

Reporting interval: not applied.

Reporting cell status: max 3 active cells.

Event 1F parameters:


hysteresis: not used in 1F Threshold used frequency: FMCS : HHoEcNoThreshold/ - 12dB (range 0..-24

dB)

Time-to-trigger: FMCS: HHoEcNoTimeHysteresis / 100 ms (range 0..5000ms)




Measurement triggering: CPICH RSCP

Reporting event: 1E: A P-CPICH exceeds an absolute threshold (triggered if one)

1F: A P CPICH falls below an absolute threshold (triggered if all)


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1F: A P-CPICH falls below an absolute threshold (triggered if all)

time

Cell 1 Cell 2

Cell 3

absolute

threshold

e.g.

P-CPICHR

scp

1E: HHoRscpCancel

1E: HHoRscpCancelTime

1F: HHoRscpThreshold

1F: HHoRscpTimeHysteresis



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UE continually monitors pilot channels of BTSs in AS

If RSCP of a Node B falls below threshold, HHoRscpThreshold, UE sends event 1F

report

RNC starts IF/IS measurements when event 1F occurs for all cells in AS

RNC stops IF/IS measurements when event 1E occurs for at least one cell of AS

Note:IF/IS measurements can be stopped if event 1Fs are cancelled by events

1E only when IFHO/ISHO was not successful and only inside the time betweenCM measurements, specified by the time InterFreqMinMeasInterval

GsmMinMeasInterval/default 10s, recommendation 2s .

UE filtering applied before event evaluation using HHoRscpFilterCoefficient

(FMCS)/200ms, range 2001600ms



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Event 1E (A primary CPICH exceeds an absolute threshold) parameters: Triggering conditions: Active set cells

hysteresis: not used in 1E Threshold used frequency: (FMCS) : HHoRscpCancel/ - 90 dBm Time-to-trigger: (FMCS): HHoRscpCancelTime/ 1280 ms Amount of reporting: infinity Reporting interval: not applied. Reporting cell status: max 3 active cells.

Event 1F (A primary CPICH falls below an absolute threshold) parameters:


Hysteresis: not used in 1F

Threshold used frequency: HHoRscpThreshold(FMCS)/ - 93 dBm

Time-to-trigger: HHoRscpTimeHysteresis(FMCS)/ 100 ms





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3G -> 2G Measurements

DL DPCH power

Th h ld

CPICH RSCP (Event 1F)

Thresholds:

HH R Th h ld

CPICH Ec/Io (Event 1F)

Thresholds:

HH E N Th h ld

ISHO parameters


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Decision Algorithm

UE Tx Power (Event 6A)

Threshold:

GsmUETxPwrThrXX

L3 filter:

GsmUETxPwrFilterCoeff

Hysteresis margin:

GsmUETxPwrTimeHyst

Data rate threshold

HHOMAxAllowedBitrateUL

UL Quality

Timer:

ULQualDetRepThreshold

Data rate threshold

HHOMAxAllowedBitrateU

L

Threshold:

GsmDLTxPwrThrXX

Data rate threshold

HHOMAxAllowedBitrateDL

(XX=AMR,CS,NrtPS,RtPS)

HHoRscpThreshold

HHoRscpCancel

L3 filter:

HHoRscpFilterCoefficient

Timers:HHoRscpTimeHysteresis

HHoRscpCancelTime

HHoEcNoThreshold

HHoEcNoCancel

L3 filter:

Done already for SHO

Timers:HHoEcNoTimeHysteresis

HHoEcNoCancelTime

AdjgTxPwrMaxTCH

AdjgRxLevMinHO (n)

GsmMeasAveWindow

GsmMeasRepInterval

GsmNcellSearchPeriod

GsmMinMeasInterval

GsmMaxMeasPeriod

Handover Triggering

Handover Execution2G-to-3G back prevention

GsmMinHoInterval

GSM measurement reporting

ISHO measurements


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After HO triggering message is sent to RNC, a RRC message Measurement Control

is sent to UE containing details of the measurement that the UE must execute.

Measurement reporting is periodical. Max 6 GSM cells could be measured by UE andreported to RNC. No filtering in measurements by UE

Upon reception of the measurements reported by the UE, RNC applies a sliding

averaging window to the RXLEV measurements. The averaged levels are used as

input to the IS-HO decision algorithm.

RNC

RRC: Measurement control message

(GSM RSSI measurements)

UE

The first measurement report

has info from the best GSM cell:

BCCH freq & RSSI, no filteringused in UE

RNC

RXLEV measurements are reported through

Measurement report messages

UE

RRC: Measurement report

RRC: Measurement report

GsmMeasRepInterval

(default 0.5s)


GSMMeasRepInterval: 0 5 seconds


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GSMMeasRepInterval: 0.5 seconds

This is the interval between measurement reports, which are sent toBTS

This parameter should be kept to 0.5 seconds. Increasing thereporting interval would increase the IS-HO process delay.

GSMMinMeasInterval: 2 s

This is Minimum Measurement Interval, wait time when the followingCM starts. In case of an unsuccessful IS-HO attempt, the networkwill deactivate compressed mode for a time period given by this

parameter, thus better value will be 2 s to speed up the reactivationof CM.

GSMMeasAveWindow: 6 reports

This is Measurement Averaging Window size, sliding window is used

GSMMaxMeasPeriod: 12 reports

This is Maximum Measurement Period which determines the

maximum allowed duration of the inter-system measurement If the RNC is not able to execute an inter-system handover, it shall

stop the inter-system measurements after the UE has sent thepredefined number of measurement reports to the RNC.


Maximum allowed duration of the inter system measurement is calculated:


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Maximum allowed duration of the inter-system measurement is calculated:

GSMMeasRepInterval* GSMMaxMeasPeriod (=0.5*12) =6s,

This seems to be too long time, because based on field measurementsBSIC and RSSI delays are about 3 seconds, so it makes senses to reducethe value of this parameter to some value about 3 seconds, otherwise, if theBSIC or RSSI measurements fail or if the IS-HO execution is not possible todue low GSM RSSI levels, the network will not deactivate compressedmode until the timer of 10 seconds has expired. Thus, decreasing theparameter value will allow the UE/network to initiate a new IS-HO attempt.Proposed value forGSMMaxMeasPeriodis 6

GSMNcellSearchPeriod: 0

This is neighbour cell search period parameter, ISHO is not alloweduntil the are enough measurement reports given by this parameter

O means that only 1 measurement result is enough for decision making

Duration of the cell search period is calculated:

GSMRepInterval* GSMNcellSearchPeriod).

ISHO: BSIC Verification


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After the selection of the target GSM cell, the RNC sends to UE the RRC message

"Measurement control which includes details to measure BSIC .

UE stops RSSI measurements and updates the transmission gap pattern to the

pattern used for BSIC decoding. The measurement reports are sent periodically to

RNC.

If the UE is unable to decode the BSIC during the given period, the BSIC

measurement operation is aborted.

RNC

RRC: Measurement control message

(BSIC decoding)

WCDM

A

IS-HO trigger Target Cell found

IS-HO

command

RSSI meas. BSIC verification

Numbers of GSM cells in

the

neighbour cell list

Reporting interval

Sliding averaging window

Transmission gap pattern

for

RSSI measurements

TBSIC depends on :

Transmission gap pattern for

BSIC decoding

TRSSI depends on


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3G -> 2G Handover decision

On this page, you find conditions, which have to be satisfied, before an inter-frequency

Inter-RAT HO Decision


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handover can be conducted. The best neighbouring cell must fulfil following criterion (best

according to Ec/No):

AVE_RXLEV_NCell(n) > GSMncellRxLevMinHO(n) + max(0, GSMncellTxPwrMaxTCH(n) -

P_max)

where

AVE_RXLEV _Ncell(n) is the averaged GSM carrier RSSI value of the GSM neighbour

cell(n), averaging done directly from dBm values (no linear averaging);

GSMMeasAveWindow/ 6, 132 meas report.

GSMncellRxLevMinHO(n) determines the minimum Required RSSI (dBm) level of the

neighbour cell(n). ( -95 dBm)

GSMncellTxPwrMaxTCH(n) indicated the maximum Tx power level (dBm) an UE may use

in GSM neighbour cell(n).

P_MAX is the maximum UE power capability.

If several GSM cells fulfils the equation above, cells are ranked based on HOPG:GSMncellPriorityCoverage/0, range 07

A cell is ranked higher than another cell if it has a higher priority level even

though its signal strength condition was worse

Inter-system HO could be forbidden during the first measurements reports from the UE, tolet the UE report all the candidate inter-system cells in its neighbourhood.

FMCG FMCGNcellSearchPeriod / 0

AVE RXLEV NCell(n) > AdjgRxLevMinHO(n) + max(0, AdjgTxPwrMaxTCH(n) - P max)

ISHO Decision


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AdjgRxLevMinHO(n)

max(0, AdjgTxPwrMaxTCH(n) - P_max)

AVE_RXLEV_NCell(n) > AdjgRxLevMinHO(n) + max(0, AdjgTxPwrMaxTCH(n) P_max)

GSM cell


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3G -> 2G Handover signalling

ISHO IS TRIGGERED

ISHO analysis with Nemo


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EVENT 1F

-(48-32)/2 = -8 dB -8.5 EcNo < -8

-115 + 11 = -104 dBm -105 Rscp < -104

Compressed mode

started


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Tstart = 17:22:41.7

Tstop = 17:22:53.7

MW = 12 s

started

Compressed mode

stopped

GsmMaxMeasPeriod x GsmMeasRepInterval +4 x GsmMeasRepInterval = 20 x 0.5+ 4x0.5=12 s

RxLev = 110 + 4 = 106 dBm


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RxLev = -110 + 4 = -106 dBm

4

AdjgRxLevMinHO = -95 dBm

POOR GSM

COVERAGE

No sui table cell

AMR Handover procedure overview (1)


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RRC connection setup

ISUP signalling

Parameters for HO event

triggere1e, e1f, e6a,e6b



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ISUP signalling

Mobility management;

several AS cell add & cell drops



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Compressed Mode

Parameters

Measurement report to

trigger CM

Mobility management;several AS cell add & cell drops



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RNC sends updated GSM

NB listUE sends inter RAT meas.ResultsRNC commands UE to verify

BSIC of

best reported cellTarget cell BSIC verifiedRNC triggers HO to GSM target

cellTiming advance information

UE ends HHO - procedure

UE is handed over to GSM

2G signalling

Physical Channel reconfiguration

RRC: Physical Channel reconfiguration


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Measurement Control new RAT NB list


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[..]

new inter RAT NB listMeasurement info


UE Measurement Report GSM cells-RSSI measurements


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measured best cell by ARFCN

measured 2nd best cell by ARFCN

measured 3rd best cell by ARFCN

measured 4th best cell by ARFCN




Measurement Control carrying target cell info


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UE shall stop measuring RSSI of RAT

and focus on best cells BSIC verificati

UE Measurement Report target GSM cell-BSIC verification


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UE reports verified BSIC of best cell t

Handover from UTRAN command


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RRC: HO from UTRAN command

Handover command GSM signalling


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L3: Handover command

2G cell information (RF&configuration)

2G cell information (Security)

2G cell information (PC)

Cell Selection and

Reselection


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Reselection

2G 3G inter working


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Idle mode Connected mode

2G -> 3G reselection


2G -> 3G handover CS AMR

2G -> 3G handover PS

3G -> 2G handover CS AMR

3G -> 2G handover PS


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Cell ReselectionCell Selection S-Ccriteria

The cell selection criteria S

are defined as follows: Squal = Qqualmeas Qqualmin

TS 25.304 5.2.3.1.2


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are defined as follows:

The cell selection criterion Sfor a suitable cell is fulfilled

when:

Where:

Squal Qqualmeas Qqualmin

Srxlev = Qrxlevmeas - Qrxlevmin - Pcompensation

Squal > 0

Srxlev > 0

Squal Cell Selection quality value, (dB).

Not applicable for TDD cells or GSM cells

Srxlev Cell Selection RX level value (dB)

Qqualmeas Measured cell quality value. The quality of thereceived signal expressed in CPICH Ec/N0 (dB) for

FDD cells. Not applicable for TDD cells or GSM cells.

Qrxlevmeas Measured cell RX level value. This is received signal,

CPICH RSCP for FDD cells (dBm), P-CCPCH RSCP

for TDD cells (dBm) and RXLEV for GSM cells (dBm).

Qqualmin Minimum required quality level in the cell (dB).

Not applicable for TDD cells or GSM cells.

Qrxlevmin Minimum required RX level in the cell. (dBm)

Pcompensation max(UE_TXPWR_MAX_RACH P_MAX, 0) (dB)

UE_TXPWR_MAX_RACH

Maximum TX power level an UE may use when

accessing the cell on RACH (read in system information), (dBm)

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

-18dB

-115dBm

-115dBm

-101dBm

intra

GSM

If system info in the cell indicates that HCS is not used (UseOfHCS) then for intra-

f i t f d i t t th UE h ll

Cell ReselectionCell Selection S-Ccriteria


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freq, inter-freq and inter-system the UE shall:

If Squal > Sintrasearch, UE need not perform intra-frequency measurements.If Squal Sintersearch, UE need not perform inter-frequency measurements

If Squal SsearchRAT m, UE need not perform measurements on cells of RAT

"m".

If Squal


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Sintrasearch

Sintersearch

SsearchRAT

WCDMA

CELL

1234

Sintrasearch = 4 dB: Equate to 16dB Ec/No

Sintersearch = 2 dB: Equate to 18dB Ec/No

SsearchRAT m, = 0dB: Equate to 20dB Ec/No

MEASURE1 Squal > Sintrasearch None

2 Sintersearch < Squal Sintrasearch Intra-frequency cells

3 SsearchRATm < Squal

Sintersearch

Intra- and inter-frequency cells

4 Squal SsearchRATm Intra-, inter-frequency and inter-RAT cells

The following cell re-selection criteria is used for intra-freq, i

nemo - events and definition

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