NSN 3G FAQ

Questions

1 © NOKIA topic: UTRAN Control Protocfol Overview/ July 2003 /Markus Wimmer

The Physical Layer• How are the physical channel characterised in the FDD mode?• How are the physical channel characterised in the FDD mode?

A: They are characterised by the UARFCN and spreading code.• What attributes characterise transport blocks and transport block sets?

A: transport block: transport block size, TTI, error protection scheme, CRC cycleA: transport block: transport block size, TTI, error protection scheme, CRC cycle size, rate matchingtransport block set: transport block set size.

• Transport channels are used for?A: exchange data between the MAC layers of RNC and UE.

• Which physical channels are required for cell synchronisation?A: P-SCH, S-SCH, & P-CPICH

• What kind of information gains the UE from the S-SCH?A: Slot synchronisation and scrambling code group determination.

• Name three different L1 measurements done by the UE.A: CPICH RSCP CPICH Ec/No UTRAN carrier RSSIA: CPICH RSCP, CPICH Ec/No, UTRAN carrier RSSI

• What is T_cell used for?A: It is used to introduce a timing delay between cells, which are made available by one Node B Idea: The SCHs CPICHs etc are started at the same time in


by one Node B. Idea: The SCHs, CPICHs, etc. are started at the same time in neighbour cells.

• Which transport channels can be found on a S-CCPCH?A: FACH, PCH

The Physical Layer• The UE receives a paging indication on the PICH When is the associated PCH• The UE receives a paging indication on the PICH. When is the associated PCH

information sent?Its transmission of the S-CCPCH starts 7680 chips after its associated PICH frame.frame.

• How does a Node B know which power to set for the data part in the S-CCPCHA: The transmit power level is sent from the Node B with the TBs and TFI to the Node B. The Node B calculated the transmit power, which is the max. transmit power for the S-CCPCH minus the Transmit Power Level value.

• Explain the meaning of „preamble cycle“. (PRACH)A: The UE can only sent the PRACH control part after the reception of the AI. If it does not get a notification, or a negative notification, then it attempts to access UTRAN a little while later on again. The preamble cycle indicates, how often the UE may attempt to access the network, before it aborts the access process.Name the power offsets of the DL DPCH• Name the power offsets of the DL DPCH.A) P01 for the TFCI bits, Po2 for the TPC bits, Po3 for the pilot bits.

• How many DL inner loop power control modes exist?A) 2


A) 2• What is the nominal power relation Aj between the DPDCH and the DPCCH?

A: Its the relationship of the output power for the two channels.• Which uplink inner loop power control algorithm is used during the power control

RRC Mode, ...• Name the UTRA RRC connected mode substates• Name the UTRA RRC connected mode substates.

A: CELL_DCH, CELL_PCH, CELL_FACH, URA_PCH.• Which SIB is used to transmit NAS information, UE timers, and counters?

A: SIB 1.A: SIB 1.• How is a UE in the RRC connected sub-state CELL_FACH informed about

changes in the system information?A: it is informed via the message System Information Change Indication (on the FACH).

• In which RRC states are Paging Type 1 and Paging Type 2 applied?A: Paging Type 1: UE is in the RRC-idle, or in the RRC connected state CELL_PCH or URA_PCH state.Paging Type 2: UE is in the CELL_FACH or CELL_DCH state.

• Is a UE in the URA_PCH state initiating a URA update, when it changes the RNC supply area?supply area?A: Yes – an URA comprises cells, which are under the control of a single RNC.

• Which timer is started, when a UE in the CELL_FACH state detects, that it is out of service area?


of service area?A: T317

• Which timer is used for periodic cell updates or periodic ura updates?A: T305

Cell Selection and Reselection• Name the two modes of PLMN selection and reselection• Name the two modes of PLMN selection and reselection.

A: manual and automatic mode.• In how far does a UE consider access class restrictions, when it selects a cell to

camp on?camp on?A: it ignores access class restrictions.

• What tries a UE in the RRC idle mode, when it is in the state „Any Cell Selection“?A: It tries to find any cell to camp on.

• A cell fulfils the cell selection criterion S. What does that mean?A: The cell is suitable to camp on.

• Name the cell selection criterion S (FDD mode).A: Quality criterion: Squal = Qqualmeas – Qqualmin > 0, andReceive level criterion: Srxlev = Qrxlevmeas - Qrxlevmin – PcompensationThe UE camps on a cell with Squal > S (no HCS) What impact does this• The UE camps on a cell with Squal > Sintrasearch (no HCS). What impact does this have on the measurements of the UE. A: There is no need to measure neighbour cells.

• Is the tempory offset TO applied in the cell-ranking criterion R when HCS is not


Is the tempory offset TOn applied in the cell-ranking criterion R, when HCS is not is use?A: no.

• What will the UE do, if the serving cell is not fulfilling the cell selection criterion for

RRC Connection Establishment• List the RRC messages exchanged between the UE and the RNC in a successful• List the RRC messages exchanged between the UE and the RNC in a successful

RRC connection establishment.A: UE to RNC: RRC Connection Request; RNC to UE: RRC Connection Setup; UE to RNC: RRC Connection Setup Complete.UE to RNC: RRC Connection Setup Complete.

• Can the RNC change the RRC mode of the UE with the RRC Connection Setup message?A: Yes, with the RRC State Indicator.

• Which protocol instances will be configured in the UE with the reception of the RRC Connection Setup message?A: PHY layer, MAC Layer, RLC (signalling) instances.

• Name the RLC mode of operation. Which one is used for the BCCH, and which one for NAS-signalling messages?A: transparent mode (BCCH), unacknowledged mode, acknowledged mode (NAS Signalling PDUs)(NAS-Signalling PDUs)

• How many logical channels exist for one radio bearer?A: one or two; the maximum is two.


RRC Connection Establishment• Are the RBs available after the RRC connection establishment be used for• Are the RBs available after the RRC connection establishment be used for

speech transmission? Motivate your answer with one or two sentences.A: No. A radio bearer in the user plane has to be set up in accordance with the Qos profile for speech.Qos profile for speech.

• How often can the UE attempt an RRC Connection request?A: N300 times (made available by SIB 1).

• The RNC sends the RRC Connection Release message to the UE. What is the UE‘s response, when it is in the CELL_DCH state? A: It returns N308 times the message RRC Connection Release Complete to the RNC. The time interval between these messages is T308.


WCDMA Measurements in the UE• How does UTRAN control the measurements in the UE (consider all RRC• How does UTRAN control the measurements in the UE (consider all RRC

modes)?A: UTRAN controls it via the System Information (BCCH) and the RRC message Measurement Control (for Ues in the CELL DCH sub-state).Measurement Control (for Ues in the CELL_DCH sub state).

• Name the two measurement reporting modes, as set by a Measurement Control message:A: measurement reporting modes: periodical reporting / event triggered reporting.

• In which RRC states is the traffic volume measurement required, and what are the consequences of its use?A: in the RRC sub-states CELL_DCH and CELL_FACH. Based on the uplink traffic volume (and on the downlink traffic volume, which is determined in the RNC), the RNC decides, whether to run the connection in the CELL_DCH or CELL_FACH state.What happens when the UE reports 6G (normal case)?• What happens, when the UE reports 6G (normal case)?A: The UE has moved closer to the Node B of the cell, mentioned in the 6G report. The RNC sets a timing adjustment at the Node B (multiple of 256 chips). Most probably the transmission is done 256 chips later


Most probably, the transmission is done 256 chips later. • Which UE internal measurement reporting events indicate a coverage problem?

A: 6A, 6D.

WCDMA Measurements in the UE• Can inter-frequency measurements only done in the compressed mode? (Take• Can inter-frequency measurements only done in the compressed mode? (Take

care!)A: Yes – but only if your UE has a dual RX.

• Which intra-frequency measurement event is often used to indicate a coverageWhich intra frequency measurement event is often used to indicate a coverage problem?A: 1F.

• In measurement 1A and 1B, reporting ranges are used. What are the consequences, if in 1A, the reporting range constant is too wide or too small?A: The reporting events are normally used in the RNC for soft handover decisions. If the range is too wide, the Soft HO area is large. Thus many soft handovers take place, which increases the transmission overhead. The DL throughput is reduced due to the larger number of served Soft HOs in the Node Bs. If the range is too small there may be a ping pong effect between neighbouringIf the range is too small, there may be a ping-pong effect between neighbouring cells, resulting in increased signalling. Due to the lacking macrodiversity, the DL throughput may be reduced.

• The UE must perform inter-RAT measurements in the compressed mode while


The UE must perform inter-RAT measurements in the compressed mode while simultaneously serving a speech call. List how speech can be transmitted in the compressed frames, starting with the highest preferable option.A: 1) use puncturing 2) use a lower AMR rate incl. Puncturing, 3) use SF/2 4) use

GSM Measurements for Inter-RAT Cell Reselection & H• GSM WCDMA interworking: Which network element initiated the cell re-• GSM – WCDMA interworking: Which network element initiated the cell re-

selection, which one the inter-system HO?A: cell re-selection: UE; HO: BSC

• What is the maximum number of reported cells in GSM? how many of them canWhat is the maximum number of reported cells in GSM? how many of them can be WCDMA cells? How many cells can be reported with an enhanced measurement report?A: 6 cells are reported; the maximum number of WCDMA can be 3; an enhanced measurement report allows reporting of up to 12 cells.

• How many cells can a multi-RAT MS monitor?A: 64.

• Can you think about a scenario, where a HO to a weaker WCDMA cell is supported and preferable?A: The WCDMA and GSM base station are co-located. The GSM cell is used for coverage the WCDMA for capacity The coverage area of the WCDMA cell is onlycoverage, the WCDMA for capacity. The coverage area of the WCDMA cell is only close to the base station site (e.g. cell radius 3 km), while the GSM base station supplies distance subscribers (e.g. cell radius 15 km). To reduce the load in the GSM cell multi-RAT phones close to the base station site are directed to UMTS


GSM cell, multi-RAT phones close to the base station site are directed to UMTS.

MM & CM• Name the three types of MM procedures• Name the three types of MM procedures

A: MM common procedures, MM specific procedures, MM connection management procedures

• What kind of GMM procedure is the GPRS ATTACH?What kind of GMM procedure is the GPRS ATTACH?A: Its a GMM specific procedure.

• Name the PMM (or GMM) mobility management states.A: PMM-idle, PMM-connected, PMM-detached.

• Is the Gs interface in use with NMO II?A: No.

• Which messages inform the UE about the periodic routing area update timer?A: The timer T3312 is transmitted in the messages ATTACH ACCEPT and ROUTING AREA UPDATE ACCEPTS.

• What is the difference between a normal (PS) detach and a power off detach?A: In both cases the UE sends the DETACH REQUEST message If the UE wasA: In both cases, the UE sends the DETACH REQUEST message. If the UE was powered off and indicated this in the message, the RNC won‘t return a response. Otherwise, the UE expect to get a DETACH ACCEPT message.


MM & CM• What is the task of the Service Request procedure?• What is the task of the Service Request procedure?

A: It is responsible to establish a secure signalling connection between the UE and the 3G-SGSN.

• What are TFT used for?What are TFT used for?A: they hold attributes for IP packets, so that IP PDU can be allocated to the correct PDP context. This is necessary, if secondary PDP contexts are supported.


UTRAN Control Protocol Overview• Name the UTRAN specific L3 signalling protocols• Name the UTRAN specific L3 signalling protocols.

A: RANAP, RRC, NBAP, RNSAP• Name RANAP‘s elementary procedure classes.

A: EP with response, EP without response, EP with multiple responses.A: EP with response, EP without response, EP with multiple responses. • Name 4 RANAP services

A: S-RNC relocation, RAB management, NAS PDU transport, location reporting, paging, Iu signalling connection management.

• Name 5 RNSAP servicesA: paging, relocation execution, compressed mode control, measurements on dedicated resources, CTCH resource management, PhyCh reconfiguration, CCCH signalling transfer, radio link management.

• Name 5 NABP servicesA: Cell Config. Mgt., System Information Mgt., CTCH Mgt., CTCH resource Mgt., measurements on common and dedicated resources radio link Mgt resourcemeasurements on common and dedicated resources, radio link Mgt., resource event status, configuration alignment, general error reporting, DL power drift correction.


NSN 3G FAQ

Documents

Transcript of NSN 3G FAQ