Nemo Analysis Workshop
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Transcript of Nemo Analysis Workshop
Topics
1.Nemo Events and Definition2.RRC and Layer3 messages3.SIB Information,Measument Control (MC),Measurement Report (MR)4.CS and PS Call Flow5.Cell Reselection, SHO and ISHO
Topics
1.Nemo Events and Definition2.RRC and Layer3 messages3.SIB Information,Measument Control (MC),Measurement Report (MR)4.CS and PS Call Flow5.Cell Reselection, SHO and ISHO
Nemo Events and Definitions
Nemo Events and Definitions
Nemo Events and Definitions
Nemo Events and Definitions
MOC
MTC
MOC/MTC Call Flow timing
Nemo Events and Definitions
Nemo Events and Definitions
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
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/ URA update?
RRC and Layer-3 Messages
System Information Blocks (SIB)
RRC Modes
• DCCH and – if configured – DTCH
• Dedicate physical channel in use
• UE location known on active set cell level
• UE responsible for measurement reporting
• Cell system information on BCCH
• RRC messages on DCCH
• DCCH and – if configured – DTCH
• Dedicate physical channel in use
• UE location known on active set cell level
• UE responsible for measurement reporting
• Cell system information on BCCH
• RRC messages on DCCH
• DCCH and – if configured – DTCH
• FACH used for higher layer data transfer,
• UE monitors FACH permanently
• Uplink transmission on RACH• UE location known on serving
cell level• UE performs cell re-selection• UE responsible for
measurement reporting• Cell system information on
BCCH• RRC messages on BCCH,
CCCH and DCCH
• DCCH and – if configured – DTCH
• FACH used for higher layer data transfer,
• UE monitors FACH permanently
• Uplink transmission on RACH• UE location known on serving
cell level• UE performs cell re-selection• UE responsible for
measurement reporting• Cell system information on
BCCH• RRC messages on BCCH,
CCCH and DCCH
• no DCCH and DTCH• Before uplink transmission UE moves to
CELL_FACH• UE must be paged• RRC messages on BCCH and PCCH• In CELL_PCH
- UE location known on cell level- UE performs cell re-selection and cell updates
• In CELL URA- UE location known on URA level- UE performs cell re-selection and URA updates
• no DCCH and DTCH• Before uplink transmission UE moves to
CELL_FACH• UE must be paged• RRC messages on BCCH and PCCH• In CELL_PCH
- UE location known on cell level- UE performs cell re-selection and cell updates
• In CELL URA- UE location known on URA level- UE performs cell re-selection and URA updates
CELL_PCH and URA_PCH
CELL_FACHCELL_DCH
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_FACHThis 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 UE‘s 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_PCHIn this sub-state, the UE‘s current cell is known to the RNC. If the RNC wants to exchange data with the UE, it only needs to page the UE there. If the UE changes the cell, it must perform a cell update. Also periodical cell updates can be requested by UTRAN. To perform updates, the UE must change to the CELL_FACH sub-state. (Please note, that no uplink transmission is allowed in CELL_PCH/URA_PCH.)
• URA_PCHURA 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.
States of Bearer Allocation
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 holds measurement control information and parameters. Depending on the UE‘s 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.
Node B
UTRANSystem Information ( )
UE RNC
NBAP: BCCH Information
MIBvalue tag M
SIB 1value tag 1
SIB 2value tag 2
SIB 3value tag 3
SIB 18value tag 18
position on P-CCPCH: SFN mod 8 = 0TTI: 20 msvalue tag M: range 1..8
NBAP = Node B Application Part
UTRAN can notify UEs, that a value tag in the MIB has been changed. Hereby, the information element BCCH Modification Info is broadcasted. There are two RRC messages, which can carry this information element:
• Paging Type 1Some 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 IndicationWith 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.
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.
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 cell‘s 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 information is indicated by a value tag.
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.
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 then no 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 aphysical 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 in URA_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)
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 aphysical 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 in URA_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)
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.
SIB3System Information Block 3 (SIB 3)
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.
SIB4System Information Block 4 (SIB 4)
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.
SIB5System Information Block 5 (SIB 5)
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. SIB 5 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.
SIB7
System Information Block 7 (SIB 7)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 ... 256 times. 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.
SIB11System Information Block 11 (SIB 11)
This SIB holds measurement control information. The UE gets here the relevant date for traffic measurement, intra-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.
SIB11
SIB11
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.
System Information Block 16 (SIB 16) 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
Voice and Video are both ConversationalRRC messages information - CSRRC messages information - CS
DL SRB
UE in DUAL MODE UE in 3G LOCKED MODE
Voice AMRCS call, 64Kbps,Transparent
Video Call
Video CS 64:DL SF 32UL SF 16
Voice AMR:DL SF 128UL SF 64(16 Kbps,12.2kbps)
RRC messages information - PSRRC messages information - PSPS can also be OriginatingHighPrioritySignalling And Registration (Only for Attach)
Modify max bit rate by NemoModify max bit rate by Nemo
SIM Card QoS profile
Measurement Control (MC) and Measurement Report (MR)
UTRAN controls the measurements in the UE, either bybroadcasting system information on the BCCH, and/or bytransmitting a Measurement Control message on the DCCH.
If the UE is in the RRC idle mode, it receives relevant measurement information from the BCCH. The SIB 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. If SIB 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.
Node B
UTRAN
RNC
UESystem Information [BCCH]
I am in the RRC idle mode
Node B
UTRAN
RNC
UESystem Information [BCCH]
I am in the CELL_FACH, CELL_PCH or
URA_PCH sub-state
Node B
UTRAN
RNC
UEMeasurement 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.)
Measurement Control (MC) and Measurement Report (MR)
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-stateIn 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 then transits 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.
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.
Measurement Control (MC) and Measurement Report (MR)
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 type
of measurements. Whenever necessary, it just informs the UE to conduct the measurements of a
measurement 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 can
gain DPCH compressed mode status information.
Measurement Control (MC) and Measurement Report (MR)
UE IEs
Measurement IEs
PhyCH IEs
Measurement Identity
Measurement Command
Measurement Reporting Mode
CHOICE Measurement type
Additional measurements list
DPCH compressed mode status info
setup/modify/release
RLC AM/UM andperiodical reporting/event triggered
includes non-frequencyrelated cell info
Intra-Frequency MeasurementsInter-Frequency MeasurementsInter-RAT MeasurementsUE-Internal MeasurementsTraffic Volume MeasurementsQuality MeasurementsUE Positioning Methods
UERNC
Measurement Control ( )
RRC messages information
UL Traffic volumes High threshold information sent after RAB setup complete (CELL_DCH)
RRC messages information
UE Buffer triggers Threshold for RAB Upgrade
RRC messages information
First RAB ReconfigurationDL 32Kbps(SF64)/ UL 32Kbps SF32)
RRC messages information
UL Traffic volumes High threshold information sent after RAB setup complete (CELL_DCH)
RRC messages information
Second RAB ReconfigurationDL 384Kbps(SF8)/ UL 32Kbps (SF32)
Maximum DL bit rate for PS domain NRT data = 384 KbpsMaximum UL bit rate for PS domain NRT data = 64 KbpsInitial and minimum allowed bit rate in downlink = 32 KbpsInitial and minimum allowed bit rate in uplink = 32 Kbps
RRC messages information
Cell DCH Cell FACH
RRC messages information
Cell FACH Cell PCH
RRC messages information
Cell PCH Cell FACH
RRC messages information
Cell FACH Cell DCH
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 validityThe 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 CriteriaReporting criteria outline, what kind of intra-frequency measurements have to be conducted. A set of intra-frequency measurements were specified, but it is the operator‘s choice, which ones are used.
Intra-frequency Measurements
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 events1A: 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 CPICH1D: Change of best cell1E: 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.
Intra-frequency Reporting Events
Inter-rat
Intra-frequency Reporting Events
Intra-frequency Reporting Events
1E forcell 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
absolutethreshold
e.g.
P-C
PICH
Ec/
No
Intra-frequency Reporting Events
Neighbourhood List Combination for Intra-frequency HOs
Cell 5 Cell 6 Cell 7 Cell 8
Cell 9 Cell 10 Cell 11 Cell 12
Cell 1 Cell 2 Cell 3 Cell 4
Neighbour List Cell 6:Cell 2Cell3Cell 7
Cell 11Cell 10Cell 5
Neighbour List Cell 7:Cell 3Cell4Cell 8
Cell 12Cell 11Cell 6
Cell 3
Cell11
Cell 3
Cell11
Neighbour cells which are common to Cell 6
and Cell 7 Cell 4
Cell 8
Cell 12
Cell 6
Cell 4
Cell 8
Cell 12
Cell 6
Neighbour cells defined only for Cell 7
Cell 2
Cell7
Cell 10
Cell 5
Cell 2
Cell7
Cell 10
Cell 5
Neighbour cells defined only for Cell 6
Two Cells in the Active Set
Neighbourhood List Combination for Intra-frequency HOs
Cell 2
Cell 5
Cell 7
Cell 9
Cell 11
Cell 15
Cell 48
Cell 4
Cell 41
Cell 6
..
...
Cell 43
Cell 2
Cell 5
Cell 7
Cell 9
Cell 11
Cell 15
Cell 48
Cell 4
Cell 41
Cell 6
..
...
Cell 43
Cell 15
Cell 21
Cell 2
Cell 7
Cell 37
Cell 51
Cell 49
Cell 9
Cell 10
Cell 56
…
...
Cell 25
Cell 15
Cell 21
Cell 2
Cell 7
Cell 37
Cell 51
Cell 49
Cell 9
Cell 10
Cell 56
…
...
Cell 25
Cell 1
Cell 2
Cell 3
Cell 7
Cell 11
Cell 50
Cell 9
Cell 13
Cell 10
Cell 22
…
...
Cell 33
Cell 1
Cell 2
Cell 3
Cell 7
Cell 11
Cell 50
Cell 9
Cell 13
Cell 10
Cell 22
…
...
Cell 33
Neighbour Cells Lists Step 1Step 1
Three Cells in the Active Set
Cell2
Cell 7
Cell 9
Cell2
Cell 7
Cell 9
Common to 3 Neighbour Lists
Step 2Step 2
Cell 11
Cell 15
Cell 10
Cell 11
Cell 15
Cell 10
Cell 37
Cell 41
Cell 49
…..
…
Cell 22
Cell 37
Cell 41
Cell 49
…..
…
Cell 22
Max 32 Cells
Neighbour Cells defined for only 1 Neighbour List:
random selection Step 4Step 4
Common to 2 Neighbour Lists
Step 3Step 3
CS and PS Call Flow
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 UE has 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 cell‘s scrambling code group is known to the UE.
The UE knows the cell‘s 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 SearchCell Search
RAB 1st then RRC
UE RNCNodeB MGW/CNRRC: 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 are available: BTS, AC, Transmission.If not it sends RRC Connection Reject
T300=2s ; N300=3
L1 Synchronization
T312=6s ; N312=4
MOS CS Message Flow
RRC Connection till the RNC
UE RNCNodeB MGW/CNRRC: 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
ALCAP: ERQ (Establish Request)
ALCAP: ECF (Establish Confirm)
NBAP: Radio Link Reconfiguration Commit)
RRC: Radio Bearer Setup
RRC: Radio Bearer Setup Complete
RANAP: RAB Assignment Response
ALCAP: ERQ (Establish Request)
ALCAP: ECF (Establish Confirm)
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)
Call Established
UE RNCNodeB
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
MGW/CN
RANAP: Location ReportRRC: Measurement Control
Call Disconnect
RRC: Downlink Direct Transfer (CC: RRC Connection Release)
RRC: Uplink Direct Transfer (CC: RRC Connection Release Complete)
RRC: Uplink Direct Transfer (CC: RRC Connection Release Complete)
NBAP: Radio Link Deletion Request
NBAP: Radio Link Deletion Response
ALCAP: ERQ (Establish Request)
ALCAP: ECF (Establish Confirm)
RANAP: Direct Transfer (CC: Alerting)RRC: Downlink Direct Transfer (CC: Alerting)
UE RNCNodeB MGW/CN
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)
L1 Synchronization
NBAP: Synchronization Indication
RRC: RRC Connection Setup Complete (DCH)
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
RRC Connection Establishment – CELL DCH State
L1 Synchronization
MTC CS Message FlowRANAP: Paging
RRC: Paging Type 1
UE RNCNodeB MGW/CNRRC: 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
ALCAP: ERQ (Establish Request)
ALCAP: ECF (Establish Confirm)
NBAP: Radio Link Reconfiguration Commit)
RRC: Radio Bearer Setup
RRC: Radio Bearer Setup Complete
RANAP: RAB Assignment Response
ALCAP: ERQ (Establish Request)
ALCAP: ECF (Establish Confirm)
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)
Call Established
UE RNCNodeB
RANAP: Direct Transfer (CC: Connect)RRC: Downlink Direct Transfer (CC: Connect)
RRC: Uplink Direct Transfer (CC: Connect Acknowledge)
RANAP: Direct Transfer (CC: Connect Acknowledge)
MGW/CN
RANAP: Location ReportRRC: Measurement Control
RANAP: Direct Transfer (CC: Alerting)RRC: Downlink Direct Transfer (CC: Alerting)
UE NodeB RNC SGSNNBAP: Radio Link Setup Request
NBAP: Radio Link Setup Response
AAL2SIG: ERQ
AAL2SIG: ECF
NBAP: Synchronization Indication
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 & Ciphering Request)
RRC: Downlink Direct Transfer (MM: Authentication & Ciphering Request)
RRC: Uplink Direct Transfer (MM: Authentication & Ciphering Response)RANAP: Direct Transfer (MM: Authentication & Ciphering Response)
RANAP: Security Mode CommandRRC: Security Mode Command
RRC: Security Mode CompleteRANAP: Security Mode CompleteRANAP: Common ID
MOS PS Message Flow
L1 Synchronization
RRC: RRC Connection Request (RACH)
FP: Downlink SynchFP: Uplink Synch
RRC: RRC Connection Setup Complete (DCH)
RRC Connection Establishment – CELL DCH State
RRC: RRC Connection Setup (FACH) [RRCconnRepTimer1/2(100ms,1s)]
RNC checks if resources are available: BTS, AC, Transmission.If not it sends RRC Connection Reject
L1 Synchronization
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)
UE NodeB RNC SGSNMOS PS Message Flow
NBAP: Radio Link Reconfiguration Commit
RRC: Radio Bearer Reconfiguration
RRC: Radio Bearer Reconfiguration Complete
NBAP: Radio Link Reconfiguration Prepare
NBAP: Radio Link Reconfiguration Ready
RRC: Radio Bearer Setup
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)
RANAP: RAB Assignment Request
RRC: Measurement Control
RRC: Measurement Repor (Trafic Volume Reports 4a)
AAL2SIG: ERQAAL2SIG: ECF
RAB EstablishmentSRB + DCH 0/0
RL modification procedure:SRB+DCH, HW resources checked
Uplink & Downlink Data Transfer
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
NBAP: Radio Link Reconfiguration Prepare
NBAP: Radio Link Reconfiguration Ready
AAL2SIG: ERQAAL2SIG: 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)
UE NodeB RNC SGSN
RANAP: Iu Release Command
RANAP: Iu Release CompleteRRC: Radio Bearer Release Complete
RRC: RRC Connection Release
RRC: 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
MOS PS Message Flow
Real traffic transfer
Bearer setupRRC
setup
9:52:53 : C09 AMR
Soft Handover
121 © 2006 Nokia
Handover Types
• 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
• 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
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 (AdjsLAC) & RAC (AdjsRAC) are also in ADJS parameter set
ADJS Parameters
125 © 2006 Nokia
Maximum number of neighbours
• The maximum number of neighbours that can be defined in RNC database 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
127 © 2006 Nokia
Soft Handover
• 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
primary CPICH (Ncell replacement)– Cell individual offsets for modifying measurement reporting
behaviour– Mechanism for forbidding a neighbor ing cell to affect the reporting
range
• Handover decision performed by RNC based on measurements and available resources
• Admission Control can reject the branch addition in case the maximum load is achieved in DL (threshold + offset), valid both for RT and NRT bitrates.
• Hard blocking may prevent branch addition
130 © 2006 Nokia
1A: A Primary CPICH Enters the Reporting Range
Strongest CPICH in AS
time
Ec/Io
P CPICH 3
P CPICH 1
P CPICH 2
1
2
AdditionWindow
AdditionTime
AdditionReportingInterval
RNC
MeasurementReport
Add tothe AS?
no
ActiveSetWeightingCoefficient
34
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
1B: A Primary CPICH leaves the Reporting Range
Remove the reported cell from the AS
135 © 2006 Nokia
reportCriteria intraFreqReportingCriteria : { eventCriteriaList { { event e1a : { triggeringCondition monitoredSetCellsOnly, 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 },
Extract from SIB 11• SIB 11 contains the relevant
parameters to read when in idle mode
• These are valid in connected mode prior 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 this mapping)
• Addition time = 100 ms
• Reporting interval = 500 ms
• Drop window = 3 dB (factor of 2 mapping between the signalled value and the actual value)
• Drop time = 640 ms
Soft and Softer Handover (case1)
137 © 2006 Nokia
time
weakest CPICH3 in AS
Ec/Io
P CPICH 3
P CPICH 1
P CPICH 2
P CPICH 4
AS has 3 cells
ReplacementReportingInterval3
1
2
ReplacementWindow
ReplacementTime
MeasurementReport
RNC
ASupdate?
no
1C: A non-active CPICH becomes better than an active primary CPICH
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.
Soft and Softer Handover (case 2)
• 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 and second 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 elements via a measurement control message
• Nokia’s implementation is that the values in the measurement control message are the same as those within SIB 11
• Events 6F and 6G are configured in a similar fashion i.e. within SIB 11 and subsequently with a measurement control message
140 © 2006 Nokia
Individual Ncell Offset
time
P CPICH 1
P CPICH 2
P CPICH 3
Reporting
Range
Reporting Event
1B
Reporting Event
1A
AdjsEcNoOffset
Enlarging Cell 3 by x dB
Ec/Io
141 © 2006 Nokia
Forbidding Neighbour Cell from Reporting Range
Time
P CPICH 1
P CPICH 2
P CPICH 3
PCPICH3 is forbidden to affect the reporting range as its quality is quite unstable.
Reporting
Range
AdjsDERR
Ec/Io
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
UE moving
Branch deletion
Soft Handover signalling
143 © 2006 Nokia
Event 1A(Add)
Event 1B(Drop)
Event 1C(Replace)
Active set cells +2 monitored set
cells
Monitored set cells
Addition Window/4 dB
Active set cellsActive set cellsDrop Window/
6 dB
Active set cells +2 monitored set
cells- Replacement
Window/2 dB
Addition Time/100 ms
AdditionReportingInterval/0.5 s
Drop time/640 ms -
Replacementtime/100 ms
ReplacementReportingInterval/
0.5s
Event Reporting cell status
Triggering Condition
Reporting Range/Hysteresis Time to Trigger Reporting
Interval
SHO Summary
• 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
144 © 2006 Nokia
RRC Connection Release
• If difference between the best AS cell and the NS cell is too high and SHO is not performed, 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
145 © 2006 Nokia
Inter-RNC Mobility
• 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 Iur connection between the RNCs involved
– SRNS relocation: the UE will be connected to the CN via the “new” RNC. It is the Nokia implemented method
*) SRNS relocation needs core network support; 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 *)
146 © 2006 Nokia
UE not involved SRNC Relocation for RT
UETarget RNC
SRNC Relocation Decision
SRNC operation started
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 RNC when all the cells of the active set belong to a different RNC. The SRNC sends a Relocation Required
• The CN evaluates if the relocation is possible and in that case, it sends a Relocation Request to the target RNC with parameters for the bearer establishment
• Relocation Command sent from CN to Source RNC with UTRAN information and bearer parameters
• After that, the Source RNC sends Relocation Commit message over Iur to the Target RNC
• When target RNC starts to act as Serving RNC, it sends a Relocation Detect message to CN. This message has no parameters
• At the same time UTRAN Mobility Information is sent to the UE, to inform that the relocation is performed
• After the confirm, the target RNC informs CN with Relocation Complete –message that the relocation procedure was successful and Iu is released from source RNC
Start RelocPrep
Stop RelocPrep
Start RelocOverall
Start RelocOverall
Stop RelocOverall
Stop RelocOverall
RelocationSupport =1NrncRelocationSupport =1
147 © 2006 Nokia
UE involved: Combined SRNC Relocation and inter-RNC HHO for RT
UETarget RNC
SRNC Relocation Decision
L1 sync. Established between BTS and UE
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
RelocationSupport =1NrncRelocationSupport =1
Start RelocPrep
Stop RelocPrep
Start RelocOverall
Stop RelocOverall
Start RelocOverall
Stop RelocOverall
Inter-system Handover (ISHO)
ISHOInter System Handover 3G -> 2G
GeneralGeneral
Downlink DPCH powerUL Quality
deteriorationUE Tx power CPICH RSCP CPICH Ec/I0
RAN Internal measurements Configured UE measurements
Initiate Compressed ModeConfigure GSM measurements
UE Reports GSM RSSI measurements
GSM CellMeets HO condition ?
Initiate Handover
Initiate Compressed ModeConfigure GSM measurements
PS
CS
UE Reports GSM BSIC measurements
150 © 2006 Nokia
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 HHOMAxAllowedBitrateUL
DL DPCH power•Threshold: GsmDLTxPwrThrXX•Data rate threshold HHOMAxAllowedBitrateDL
(XX=AMR,CS,NrtPS,RtPS)
CPICH RSCP (Event 1F)•Thresholds:HHoRscpThreshold HHoRscpCancelL3 filter: HHoRscpFilterCoefficient•Timers:HHoRscpTimeHysteresisHHoRscpCancelTime
CPICH Ec/Io (Event 1F)•Thresholds:HHoEcNoThresholdHHoEcNoCancel•L3 filter:Done already for SHO•Timers:HHoEcNoTimeHysteresisHHoEcNoCancelTime
AdjgTxPwrMaxTCHAdjgRxLevMinHO (n)GsmMeasAveWindow
GsmMeasRepIntervalGsmNcellSearchPeriodGsmMinMeasIntervalGsmMaxMeasPeriod
Handover Triggering
Handover Execution2G-to-3G back prevention
GsmMinHoInterval
GSM measurement reporting
ISHO parameters
2 more optional triggers in RAN04:
IMSI based ISHO Emergency ISHO (EMISHO)
151 © 2006 Nokia
Measurement Control Parameters: FMCG
• 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
measurements BSIC and RSSI delays are about 3 seconds, so it makes senses to reduce the value of this parameter to some value about 3 seconds, otherwise, if the BSIC or RSSI measurements fail or if the IS-HO execution is not possible to due low GSM RSSI levels, the network will not deactivate compressed mode until the timer of 10 seconds has expired. Thus, decreasing the parameter value will allow the UE/network to initiate a new IS-HO attempt. Proposed value for GSMMaxMeasPeriod is 6
• GSMNcellSearchPeriod: 0 – This is neighbor cell search period parameter, ISHO is not allowed until
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 Process Overview
HO Triggering Thresholds set in RNCHO Triggering Thresholds set in RNC
Event Triggered Coverage/Capacitybased HO fulfilled in RNC
Event Triggered Coverage/Capacitybased HO fulfilled in RNC
RNC commands selected UE(s) to startIF/IS measurements
RNC commands selected UE(s) to startIF/IS measurements
Measurements are done in Compressed Mode (CM)
Measurements are done in Compressed Mode (CM)
UE reports GSM cells withstrongest RSSI signals to RNC
UE reports GSM cells withstrongest RSSI signals to RNC
RNC makes HO decision andcommands UE to target cell
RNC makes HO decision andcommands UE to target cell
RSSI measurements and BSICverification for GSM cells
RSSI measurements and BSICverification for GSM cells
Different decision methods for IF HOOnly 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
153 © 2006 Nokia
• BSIC verification always performed for AMR calls – no interrupt in voice call
CNUE
Node B
RNC
RRC: Measurement Report
RRC: Measurement Control
NBAP: Radio Link Reconfiguration PrepareNBAP: Radio Link
Reconfiguration ReadyNBAP: Radio Link Reconfiguration CommitRRC: Physical Channel
ReconfigurationRRC: Physical Channel Reconfiguration Complete NBAP: Compressed Mode
Command
RRC: Measurement Report
RRC: Measurement Control
NBAP: Compressed Mode Command
RRC: Measurement Report
RRC: Measurement Control
RRC: Handover from UTRAN Command
GSM BSIC Identification
GSM RSSI Measurement
ISHO triggering (2 reasons are possible)
Initial Compressed Mode Configuration
RANAP: Relocation Required
RANAP: Relocation Command
RANAP: IU Release Command
RANAP: IU Release Complete
ISHO 3G -> 2G - AMR Signalling Flow
154 © 2006 Nokia
• In most cases BSIC verification is not required (data interrupt as UE moves to 2G)
• PS makes use of RRC: CELL CHANGE ORDER FROM UTRAN message
UE
Node B
RNC
RRC: Measurement Report
RRC: Measurement Control
NBAP: Radio Link Reconfiguration Prepare
NBAP: Radio Link Reconfiguration Ready
NBAP: Radio Link Reconfiguration Commit
RRC: Physical Channel Reconfiguration
RRC: Physical Channel Reconfiguration Complete
NBAP: Compressed Mode Command
RRC: Measurement Report
RRC: Measurement Control GSM RSSI Measurement
ISHO triggering (5 reasons are possible)
Initial Compressed Mode Configuration
CN
RANAP: SRNS Context Request
RANAP: SRNS Context Response
RANAP: IU Release Command
RANAP: IU Release Complete
RRC: Cell Change Order from UTRAN
RANAP: SRNS Data Forward Command
ISHO 3G -> 2G - PS Signalling Flow
3G -> 2G Handover measurement triggering
IS Handover Triggering Reasons
1. DL DPCH approaches itsmaximum allowed powerFMCI: IFHOcauseTxPwrDLFMCG: GSMcauseTxPwrDL
2. Quality deterioration report from UL outer loop PCFMCI: IFHOcauseUplinkQualityFMCG: GSMcauseUplinkQuality
4. UE Tx power approaches itsmaximum allowed power, event 6A/6DFMCI: IFHOcauseTxPwrULFMCG: GSMcauseTxPwrUL
5 . Low measured absoluteCPICH RSCP, events 1E/1FFMCI: IFHOcauseCPICHrscp, FMCG: GSMcauseCPICHrscp
3. Low measured absolute CPICH Ec/No, event 1E/1F FMCI: IFHOcauseCPICHEcNoFMCG: 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 = FMCIFrequency Measuring Control for Inter-System (GSM) = FMCG
Measurement triggering: CPICH Ec/No
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)
e.g.
P-C
PICH
Ec/
No
time
Cell 1 Cell 2
Cell 3
absolutethreshold
1E: HHoEcNoCancel
1E: HHoEcNoCancelTime
1F: HHoEcNoThreshold
1F: HHoEcNoTimeHysteresis
Measurement triggering: CPICH Ec/No
• RNC starts IF/IS measurement when event 1F occurs for all cells in the 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 if event 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
Measurement triggering: CPICH Ec/No
• Event 1E parameters:– 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:– Triggering conditions: Active set cells– 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)– Amount of reporting: infinity– Reporting interval: not applied.– Reporting cell status: max 3 active cells.
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)
time
Cell 1 Cell 2
Cell 3
absolutethreshold
e.g.
P-C
PICH
Rsc
p
1E: HHoRscpCancel
1E: HHoRscpCancelTime
1F: HHoRscpThreshold
1F: HHoRscpTimeHysteresis
Measurement triggering: CPICH RSCP
• 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 between CM measurements, specified by the time InterFreqMinMeasInterval GsmMinMeasInterval/default 10s, recommendation 2s .
• UE filtering applied before event evaluation using HHoRscpFilterCoefficient (FMCS) /200ms, range 200…1600ms
Measurement triggering: CPICH RSCP
• 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:– Triggering conditions: Active set cells– Hysteresis: not used in 1F– Threshold used frequency: HHoRscpThreshold (FMCS)/ - 93 dBm– Time-to-trigger: HHoRscpTimeHysteresis (FMCS)/ 100 ms– Amount of reporting: infinity– Reporting interval: not applied.– Reporting cell status: max 3 active cells.
3G -> 2G Measurements
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 HHOMAxAllowedBitrateUL
DL DPCH power•Threshold: GsmDLTxPwrThrXX•Data rate threshold HHOMAxAllowedBitrateDL
(XX=AMR,CS,NrtPS,RtPS)
CPICH RSCP (Event 1F)•Thresholds:HHoRscpThreshold HHoRscpCancelL3 filter: HHoRscpFilterCoefficient•Timers:HHoRscpTimeHysteresisHHoRscpCancelTime
CPICH Ec/Io (Event 1F)•Thresholds:HHoEcNoThresholdHHoEcNoCancel•L3 filter:Done already for SHO•Timers:HHoEcNoTimeHysteresisHHoEcNoCancelTime
AdjgTxPwrMaxTCHAdjgRxLevMinHO (n)GsmMeasAveWindow
GsmMeasRepIntervalGsmNcellSearchPeriodGsmMinMeasIntervalGsmMaxMeasPeriod
Handover Triggering
Handover Execution2G-to-3G back prevention
GsmMinHoInterval
GSM measurement reporting
ISHO parameters
ISHO measurements• 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 and reported 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)
Measurement Control Parameters: FMCG
• GSMMeasRepInterval: 0.5 seconds– This is the interval between measurement reports, which are
sent to BTS– This parameter should be kept to 0.5 seconds. Increasing the
reporting interval would increase the IS-HO process delay.• GSMMinMeasInterval: 2 s
– This is Minimum Measurement Interval, wait time when the following CM starts. In case of an unsuccessful IS-HO attempt, the network will deactivate compressed mode for a time period given by this parameter, thus better value will be 2 s to speed up the reactivation of 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 the predefined number of measurement reports to the RNC.
Measurement Control Parameters: FMCG
• 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 measurements BSIC and RSSI delays are about 3 seconds, so it makes senses to reduce the value of this parameter to some value about 3 seconds, otherwise, if the BSIC or RSSI measurements fail or if the IS-HO execution is not possible to due low GSM RSSI levels, the network will not deactivate compressed mode until the timer of 10 seconds has expired. Thus, decreasing the parameter value will allow the UE/network to initiate a new IS-HO attempt. Proposed value for GSMMaxMeasPeriod is 6
• GSMNcellSearchPeriod: 0 – This is neighbour cell search period parameter, ISHO is not allowed
until 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
• 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)
WCDMA
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
3G -> 2G Handover decision
On this page, you find conditions, which have to be satisfied, before an inter-frequency 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, 1…32 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 0…7
• 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, to let the UE report all the candidate inter-system cells in its neighbourhood.
• FMCG FMCGNcellSearchPeriod / 0
Inter-RAT HO Decision
AdjgRxLevMinHO(n)
max(0, AdjgTxPwrMaxTCH(n) - P_max)
AVE_RXLEV_NCell(n) > AdjgRxLevMinHO(n) + max(0, AdjgTxPwrMaxTCH(n) - P_max)
GSM cell
ISHO Decision
3G -> 2G Handover signalling
ISHO IS TRIGGEREDEVENT 1F
-(48-32)/2 = -8 dB -8.5 EcNo < -8
-115 + 11 = -104 dBm -105 Rscp < -104
ISHO analysis with Nemo
Tstart = 17:22:41.7
Tstop = 17:22:53.7
MW = 12 s
Compressed mode started
Compressed mode stopped
•GsmMaxMeasPeriod x GsmMeasRepInterval +4 x GsmMeasRepInterval = 20 x 0.5+ 4x0.5=12 s
RxLev = -110 + 4 = -106 dBm
4
AdjgRxLevMinHO = -95 dBm
POOR GSM POOR GSM COVERAGECOVERAGE
No suitable cellNo suitable cell
AMR Handover procedure overview (1)
RRC connection setup
ISUP signalling
Parameters for HO event triggere1e, e1f, e6a,e6b
AMR Handover procedure overview (2)
ISUP signalling
Mobility management; several AS cell add & cell drops
AMR Handover procedure overview (3)
Compressed Mode Parameters
Measurement report to trigger CM
Mobility management; several AS cell add & cell drops
AMR Handover procedure overview (4)
RNC sends updated GSM NB listUE sends inter RAT meas. ResultsRNC commands UE to verify BSIC ofbest reported cellTarget cell BSIC verifiedRNC triggers HO to GSM target cellTiming advance informationUE ends HHO - procedure UE is handed over to GSM
2G signalling
Physical Channel reconfiguration
RRC: Physical Channel reconfiguration
Measurement Control new RAT NB list
[..]
new inter RAT NB listMeasurement info
RRC: Measurement Control
UE Measurement Report GSM cells-RSSI measurements
measured best cell by ARFCN
measured 2nd best cell by ARFCN
measured 3rd best cell by ARFCN
measured 4th best cell by ARFCN
measured 5th best cell by ARFCN
measured 6th best cell by ARFCN
RRC: Measurement Report
Measurement Control carrying target cell info
RRC: Measurement Control
UE shall stop measuring RSSI of RAT NB list and focus on best cell´s BSIC verification
UE Measurement Report target GSM cell-BSIC verification
RRC: Measurement Report
UE reports verified BSIC of best cell to RNC
Handover from UTRAN command
RRC: HO from UTRAN command
Handover command GSM signalling
L3: Handover command
2G cell information (RF&configuration)
2G cell information (Security)
2G cell information (PC)
Cell Selection and Reselection
2G <-> 3G inter working
Idle mode Connected mode
2G -> 3G reselection
3G -> 2G reselection
2G -> 3G handover CS AMR
2G -> 3G handover PS
3G -> 2G handover CS AMR
3G -> 2G handover PS
3G -> 2G reselection
Cell Reselection Cell Selection S-Ccriteria
• The cell selection criteria S are defined as follows:
• The cell selection criterion S for 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 the
received 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
TS 25.304 5.2.3.1.2TS 25.304 5.2.3.1.2
• If system info in the cell indicates that HCS is not used (UseOfHCS) then for intra-freq, inter-freq and inter-system the UE shall:
• If Squal > Sintrasearch, UE need not perform intra-frequency measurements. If Squal <= Sintrasearch, perform intra-frequency measurements.
• If Squal > Sintersearch, UE need not perform inter-frequency measurementsIf Squal <= Sintersearch, perform inter-frequency measurements.
• If Squal > SsearchRAT m, UE need not perform measurements on cells of RAT "m".If Squal <= SsearchRAT m, perform measurements on cells of RAT "m".
Cell Reselection Cell Selection S-Ccriteria
Sintrasearch
Sintersearch
SsearchRAT
WCDMACELL
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
Region Condition Neighbour cells to be measured ONLY TRIGGER FOR MEASURE
1 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
Cell Reselection Cell Selection S-Ccriteria
• The following cell re-selection criteria is used for intra-freq, inter-freq & inter-RAT:
Rs = Qmeas,s + Qhysts(COMAPRED WITH SELF)
Rn = Qmeas,n – Qoffsetn(COMPARED WITH ADJACENT CELLS)
Rs = Qmeas,s + Qhysts(COMAPRED WITH SELF)
Rn = Qmeas,n – Qoffsetn(COMPARED WITH ADJACENT CELLS)
QmeasQuality value. The quality value of the received signal expressed in CPICH_Ec/No or CPICH_RSCP_LEV for FDD cells as set by the Cell_selection_and_reselection_quality_measure information element, P-CCPCH_RSCP_LEV for TDD cells and RXLEV for GSM cells.
Where:
Qhyst1This specifies the hysteresis for serving cell that is of different radio access modes or technologies AND for serving FDD cell when cell_selection_and reselection-quality_measure is set CPICH RSCP..
Qoffset1This specifies the offset between the two cells when the neighbour cells that are of different radio access modes or technologies AND for neighbour FDD cells when cell_selection_and reselection-quality_measure is set CPICH RSCP
Qhyst2This specifies the hysteresis for serving FDD cell when the cell_selection_and reselection-quality_measure is set CPICH Ec/No.
Qoffset2This specifies the offset between the two cells when neighbour FDD cells when the cell_selection_and reselection-quality_measure is set CPICH Ec/No.
Cell Reselection Cell Selection S-Ccriteria
Cell Reselection 3G -> 2G
First ranking of all the cells based on CPICH RSCP (WCDMA) and RSSI (GSM)
Rs = CPICH RSCP + Qhyst1Rn= Rxlev(n) - Qoffset1
First ranking of all the cells based on CPICH RSCP (WCDMA) and RSSI (GSM)
Rs = CPICH RSCP + Qhyst1Rn= Rxlev(n) - Qoffset1
Rn (GSM) > Rs (WCDMA)And
Rxlev (GSM) >QrxlevMin
Rn (GSM) > Rs (WCDMA)And
Rxlev (GSM) >QrxlevMin
YesNo
Cell re-selection to GSM
Cell re-selection to GSM
Neighbour WCDMA or GSM cell calculation with offset
parameter
Serving WCDMA cell calculation, with
hysteresis parameter
UE starts GSM measurements if CPICH Ec/No < qQualMin + sSearchRAT
UE starts GSM measurements if CPICH Ec/No < qQualMin + sSearchRAT
SintraSearch
SinterSearch
SsearchRAT
CPICH EcNo
qQualMin
Second ranking only for WCDMA cells based on CPICH Ec/No
Rs = CPICH Ec/No + Qhyst2Rn=CPICH_Ec/No(n)-Qoffset2
Second ranking only for WCDMA cells based on CPICH Ec/No
Rs = CPICH Ec/No + Qhyst2Rn=CPICH_Ec/No(n)-Qoffset2
Cell re-selection to WCDMA cell of highest
R value
Cell re-selection to WCDMA cell of highest
R value
ConceptConcept
S-Criteria OKS-Criteria OK
Cells with Highest HCSPriorities &H > 0
Cells with Highest HCSPriorities &H > 0
BestRBestR
Serving + measuredneighboring cellsServing + measuredneighboring cells
S-Criteria OKS-Criteria OK
BestRBestR
Serving + measuredneighboring cellsServing + measuredneighboring cells
Cells with Lower HCSPriority than in Serving cell
Cells with Lower HCSPriority than in Serving cell
BestRBestR
Fast MSIf No Cellwith H>0accept allneighbors
HCS in use: HCS not in use:
Cell Reselection 3G -> 2G
Cell Reselection Neighbour measurements summary
SintrasearchSintersearchSsearchRAT m
No need to measure neighbour cells
Intra-frequency
Sx=Squal= Ec/No
Intra-frequencyInter-freqencyInter-RAT
Higher HCS priorityIntra-frequencyInter-frequency
Intra-frequencyInter-frequency
HCS not used
HCS used
SlimitsearchRAT m
Intra-frequencyInter-frequency
Intra-frequencyInter-freqencyInter-RAT
Intra-frequencyInter-frequencyHigher HCS priority inter RAT
• There is no timer defined how long the GSM should be fulfilling the re-selection criteria
• However there is running average of 4 GSM measurements which provides some protection against ping – pong (time vice –based on DRX cycle length and as sliding window average)
• In case additional protection is needed it can be arranged by using the Qhyst1 parameter (for WCDMA serving cell RSCP) or AdjgQoffset1 (for GSM neighbouring cell RxLev)
PerformancePerformance
First ranking of all the cells based on CPICH RSCP (WCDMA) and RSSI (GSM)
Rs = CPICH RSCP + Qhyst1Rn= Rxlev(n) - Qoffset1
First ranking of all the cells based on CPICH RSCP (WCDMA) and RSSI (GSM)
Rs = CPICH RSCP + Qhyst1Rn= Rxlev(n) - Qoffset1
Cell Reselection 3G -> 2G
• When to trigger the cell reselection to 2G depends greatly on:– how much the 3G network is requested to be utilised
• target is to maximise the utilisation of WCDMA network but…
– what is the desired CSSR • …at the same time maximise the quality
– minimise the possibility of ping – pong • Due to very different fading conditions, there should be
couple of different parameter sets for 3G -> 2G reselection– Outdoor, typical outdoor to dedicated indoor (in case of
missing 3G indoor)– 3G border– Special indoor cases without dedicated 3G where the UE
speed is high (e.g. tunnels)
Parameter TuningGeneral
Parameter TuningGeneralCell Reselection 3G -> 2G
ISHOCell Reselection 3G -> 2G
Parameter TuningOutdoor
Parameter TuningOutdoor
As long as the Ec/No is >-12…-14dB the CSSR is excellent
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
> -4 -4 to -
6
-6 to -
8
-8 to -
10
-10 to
-12
-12 to
-14
-14 to
-16
-16 to
-18
-18 to
-21
<-21
Ec/No [dB]
[%]
Call Setup status statistics for each Ec/No range
qQualMin + sSearchRAT ~ -14dB
WCDMA intra frequency search should be started latest at ~ qQualMin + sSearchIntra = -8 … -10dB
2G -> 3G reselection
Cell Reselection Algorithm from GSM to FDD-WCDMA (cs)Cell Reselection List
GSM MS starts WCDMA measurements if :RLA_C< F(Qsearch_I) for 0<Qsearch_I<=7orRLA_C> F(Qsearch_I) for 7<Qsearch_I<=15
If, for suitable UMTS cell & for a period of 5 s:CPICH RSCP > RLA_C + FDD_Qoffset
CPICH Ec/No FDD_Qmin
no prioritiesbetween WCDMA neighbours
Measurement Updates:• RLA_C value of the serving cell• + least 6 strongest non serving GSM cells
at least every 5 s
check
and
WCDMA cellreselection
BCCH: FDD_Qmin, FDD_Qoffset
Fdd_Qoffset: select allways (value is -infinity)
FDD_Qmin= -13 dB
• In GSM the UE is usually set to measure the 3G neighbours all the time I.e. Qsearch_I and Qsearch_P are both set to 7
UE starts WCDMA measurements if Rxlev running average (RLA_C) is below or above
certain threshold:RLA_C Qsearch_I and Qsearch_P (GPRS)
UE starts WCDMA measurements if Rxlev running average (RLA_C) is below or above
certain threshold:RLA_C Qsearch_I and Qsearch_P (GPRS)
Cell Reselection Algorithm from GSM to FDD-WCDMA (cs)
Cell Reselection Parameters• Qsearch_I and Qsearch_P define thresholds. The threshold value also
indicates, when the measurements have to be initiated and performed. The measurements are either started, when the serving cell‘s RLA is below or above the threshold value. The default value is 15.
• FDD_Qoffset and FDD_GPRS_Offset define offset values, which have to be added to the RLA of the serving and non-serving GSM cells. The result is compared with the RSCP value of the WCDMA cell. The default parameter is 0.
• FDD_Qmin defines a minimum CPICH Ec/No threshold for WCDMA cell for cell re-selection.
• FDD_REP_QUANT defines the reporting quantity for UTRAN cell (1=Ec/No or 0=RSCP, default: 1).
• 3G_Search_PRIO is used to inidicate to the MS if 3G cells can be looked for when BSIC decoding is required. (0=no, 1=yes, default: 1)
The 3G Cell Reselection list is only used by multi-RAT MSs. The system information SI2quater and SI2ter can be used to provide 3G cell information. If the two system information messages carry 3G cell information, than their lists have to be combined in the UE‘s 3G Cell Reselection list, which may then hold up to 96 UMTS cells. Up to 8 carrier frequency bands can be stored in this list, too.
Cell Reselection AlgorithmAlgorithm for cell re-selection from GSM (GPRS) to the FDD mode in UTRANPre-requisite for cell re-selection to UMTS is, that UTRAN carrier bands are
included in the (GPRS) 3G Cell Reselection list. If so, the MS must update • RLA_C (RLA_P) value for the serving cell and• at least 6 strongest non serving GSM cellsat least every 5 seconds. Thereafter, the MS can re-select a suitable
UTRAN cell, based on the S-Criterion. If an FDD cell is suitable, following two conditions must have been met:
• For a period of 5 seconds, the measured RSCP value must exceed the PLA_C (RLA_P) of the serving GSM and of all non-serving GSM cells by the value FDD_Qoffset (FDD_GPRS_Qoffset). Did a cell re-selection occur within the previous 15 seconds, the FDD_Qoffset value is increased by 5 dB.
• The measured Ec/No value of the FDD cell must be greater or equal than the broadcasted value FDD_Qmin.
• If the UE as performed a cell re-selection to UTRAN within the previous 5 seconds, a cell re-selection back to UTRAN is not allowed, when a suitable cell can be found within GSM.
Cell Re-selection Parameters
• Range of FDD_Qmin– Recommended value is 7 (-13 dBm)
• FDD_REP_QUANT defines the reporting quantity for UTRAN cell (1=Ec/No or 0=RSCP, default 1)
• 3G_Search_PRIO parameter allows to extend the BSIC reporting interval from 10 s to 13s by checking the BSICs from non-serving BCCH carriers and also make WCDMA measurements as often as possible. Range is 0=no, 1=yes, default value 1
Defined in the SI2quater and PSI3quater if PBCCH is allocated.
ParameterParameter
Name for Sys Info (SI)
Name for Sys Info (SI)
Qsearch_IQsearch_I
2quater2quater
Qsearch_PQsearch_PQsearch_PQsearch_P
2quater2quater 3quater3quater
FDD_QMinFDD_QMin
2ter2ter
FDD_(GPRS)Qoffset
FDD_(GPRS)Qoffset
2quater2quater
FDD_REP_QUANT
FDD_REP_QUANT
2ter2ter
00
-20-20
11 22
-19 -19 -18-18
33
-17-17
44
-16-16
55
-15-15
66 77
-14-14 -13-13
Range
dBm
3G_search_PRIO
3G_search_PRIO
2(3)quarter(PBCCH)
2(3)quarter(PBCCH)
Fdd_Qmin mappingAif parameter 0 1 2 3 4 5 6 7Fdd_Qmin (old) [dB] -20 -19 -18 -17 -16 -15 -14 -13Fdd_Qmin (new) [dB] -20 -6 -18 -8 -16 -10 -14 -12
old
New mapping from 05.08 [late 2003]:
UEs have to support new parameter range !
• In case the reselection is wanted to happen immediately when the 3G is “good enough” just based on CPICH Ec/No value (RSCP threshold is not used i.e. reselection is done RSCP > Rxlev – infinity)
FDD_Qoffset (FDD_Cell_Reselect_Offse
t )
Mapped to:
Comment:
0 Always select irrespective of RSCP value
1 -28dB Reselect in case WCDAM RSCP > GSM RXLev (RLA_C) –28dB
2 -24dB
… …
14 24dB
15 28dB Reselect in case WCDAM RSCP > GSM RXLev (RLA_C) +28dB
UE can select WCDMA cell if the level of the serving GSM and non-serving GSM cells
has been exceeded by certain offset for a period of 5 s: CPICH RSCP > RLA_C + FDD_Cell_Reselect_Offset
UE can select WCDMA cell if the level of the serving GSM and non-serving GSM cells
has been exceeded by certain offset for a period of 5 s: CPICH RSCP > RLA_C + FDD_Cell_Reselect_Offset
Cell Re-selection Parameters
• As a general rule the value for FDD_Qmin parameter can be set to –11…-12 dB (i.e. for the case where the QqualMin +Ssearch_RAT = -14dB)
How to avoid ping-pong ?
UE will re-select WCDMA cell in case it's quality is acceptable:
CPICH Ec/No Minimum_FDD_Threshold
UE will re-select WCDMA cell in case it's quality is acceptable:
CPICH Ec/No Minimum_FDD_Threshold
• The “rule” to set the FDD_Qmin value has not been possible to be fulfilled until the specification change (05.08 v8.18.0, 2003-8) has been implemented to the UEs – as below
QqualMin = -18dB
QqualMin + Ssearch_RAT = -14dB
FDD_Qmin >=-12
Camping in 3G Camping in 2G Camping in 3G
CPICH Ec/No
t
FDD_Qmin >= QqualMin + Ssearch_RAT
Fdd_Qmin mappingAif parameter 0 1 2 3 4 5 6 7Fdd_Qmin (old) [dB] -20 -19 -18 -17 -16 -15 -14 -13Fdd_Qmin (new) [dB] -20 -6 -18 -8 -16 -10 -14 -12
GSM BCCH 2Quater / 2TerBCCH info
Cell Re-selection ExampleNon GPRS case
t
Serving GSM Cell
Neighbour WCDMA Cell
Ec/NoRSCP/RLA_C
5 sec.
Cell re-selection to WCDMA
FDD_Qmin=0(-20 dB)
FDD_Qoffset =6 (-8 dB)
Qsearch_I=0 (-98 dBm)
RLA_C
Measurements starts (serving cell)
Minimum Quality Requirement for WCDMA Ec/N0
RSCP
Cell Re-selection Example GPRS case
t
Serving GSM Cell (Best)
Neighbour WCDMA Cell
Ec/NoRSCP/RLA_C
5 sec.
Cell re-selection to WCDMA
FDD_Qmin=-20 dB
FDD_GPRS_Qoffset =10 (8 dB)Qsearch_P=0(-98 dBm)
RLA_P
Measurements starts (serving cell)
Minimum Quality Requirement for WCDMA
Ec/N0
RSCP