Quick Reference UMTS

8/13/2019 Quick Reference UMTS

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Quick Reference - UMTS Home : www.sharetechnote.com

3GPP Release and Main FeaturesCBS(Cell Broadcast Service)Cell Search ProcedureCell Selection - Automatic vs ManualCell Selection - in VPLMN (Cell Reselection)CPC (Continous Packet Connectivity)CQICompressed ModeConstellation (Downlink) - ConceptualCPICH Ec/Io measurement report mappingDownlink Frame TimingDRX/DTXE-DPCCHE-TFCI SelectionFrequency TableHARQ - HSDPAHARQ - HSUPAHSDPA Category TableHSUPA Category TableHSUPA - UL Grant/E-AGCH,E-RGCHLocation Updating RejectMeasurement Control and HandoverP-CCPCH RSCP measurement report mappingPRACH PowerRRC Establishment CauseRSSI measurement report mappingScrambling CodeTFI and TFCIUplink Frame Timing

3GPP Release and Main Features

< Release 7 >

Higher Order Modulation (DL 64 QAM, UL 16 QAM)CPC (Continous Packet Connectivity, TDX + DRX)Enhanced F-DPCHImproved L2 (for Higher downlink data rate)Enhanced Cell_FACH for downlinkDownlink MIMO

< Release 8 >

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Dual Cell HSDPACombination of 64 QAM and MIMOImproved L2 (for Higher uplink data rate)Enhanced Cell_FACH for uplinkCS over HSPAServing Cell Change EnhancementHS-DSCH Reception in Cell FACH

< Release 9 >

Dual Cell HSUPADual Band HSDPADual Cell HSDPA + MIMO2ms TTI Uplink range extension

< Release 10 >

Four Carrier HSDPA

CBS (Cell Broadcast Service) CBS is a kind of Short Message service. Then what is the difference between SBS and SMS ? There may be two maindifferences

SMS is one to one message and CBS is a message broadcast to many people simultaneously.SMS can be bidirectional (you can send and receive the message) and CBS is usually unidirectional(subscribers can only receive the message).

25.324 Broadcast/Multicast Control BMC23.041 Technical realization of Cell Broadcast Service (CBS)


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Cell Search Procedure Cell Search procecess in WCDMA would be described as follows (For the detailed understanding, I would recommendyou to study each of the physical channels involved in the following description).i) Every cell is tranmitting its scrambling code(Primary Scrambling Code) via CPICH.ii) UE detect the cell power, primary scrambling code and some addition info for compensating demodulation processiii) UE detect P-SCH (Primary Synchronization Code) and figure out slot boundary (start and end of each slot)iv) UE detect S-SCH (Primary Synchronization Code) and figure out frame bounday (start and end of each frame)v) UE detect P-CCPCH and decode MIB. Through this MIB, UE can figure out SFN.

Cell Selection - Automatic vs Manual


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There are two main factors influencing the cell selection process. One factor is Cell Power and the other one isvarious PLMN configuration. I will focus on PLMN based selection here but in many cases you have to consider bothCell Power and PLMN at the same time and the selection process can be more complicated in this case. Usually many phones provide two options for you to select from for selecting a cell to camp on. One is Automatic andthe other one is Manual. There is nothing for me to talk about 'Manual' mode since it is so straightforward. In manualmode, the UE camps on whatever network that user specified. If the UE cannot find the specified cell or rejected bythe cell, it would just give up without trying anything else. The issues come in when the mode is set to be 'Automatic'. 'Automatic' means "Select a cell based on a predefined

rule". Then your question would be "What is the predefined rule?". Even though 3GPP provide overal guidelines, thedetailed implementation would be up UE makers and the requirement from each specific network operator. General guideline especially guidelines regarding "PLMN" is as follows :i) Select the cell with HPLMN (Home PLMN) or EHPLMN(Equivalent HPLMN)ii) If UE lose coverage for HPLMN or EHPLMN, then try find the cell with VPLMN. More specifically, in Automatic mode, UE select the Cells with PLMNs in the following order

i) either the HPLMN (if the EHPLMN list is not present or is empty) or the highest priori ty EHPLMN that isavailable (if the EHPLMN list is present);ii) each PLMN/access technology combination in the User Controlled PLMN Selector with Access Technology data file in the SIM (in priority order);iii) each PLMN/access technology combination in the Operator Controlled PLMN Selector with AccessTechnology data file in the SIM (in priori ty order);iv) other PLMN/access technology combinations with received high quali ty signal (GSM RLA -85 dBm,UTRAN FDD - CPICH RSCP above -95 dBm) in random order;v) other PLMN/access technology combinations in order of decreasing signal quali ty.

Cell Selection - in VPLMN (Cell Reselection) If UE has camped on to the cell with VPLMN and is in IDLE mode, it has to perform following procedures

i) periodically attempts to obtain service on i ts HPLMN (if the EHPLMN list i s not present or is empty) or one of itsEHPLMNs (if the EHPLMN list is present)ii) (if failed in previous step) periodically attempts to a higher priori ty PLMN/access technology combinations

listed in User Controlled PLMN Selector or Operator Controlled PLMN Selector

I said the term "periodically". Then how this "peridicity" is determined ?The periodicity T minutes may be stored in the SIM (Higher Priority PLMN search period), T is either in the range 6minutes to 8 hours in 6 minute steps or it indicates that no periodic attempts shall be made. If no value is stored inthe SIM, a default value of 60 minutes is used

CPC (Continous Packet Connectivity) Let's suppose a situation, say Web browsing for example. While you are reading a page, you are not downloading anydata and there are no data communication between UE and the network. During this time, usually RRC state is putinto Cell_FACH and Cell_PCH. When you finish reading the page and try to go next page, in this case the RRC stateshould change back into Cell_DCH.

Another way to improve the problem related to RRC State changes would be to increase the data rate at Cell_FACH.Theoretically you can transmit the data in Cell_FACH in previous technology and ideally the throughput is around 34K. But if you really try it, you may notice the real throughput is much less than this. For HSPA+, the throuhgput forCell_FACH has been much increased by Enhanced Cell_FACH. To save battery consumption, UE can repeat very short cycles of 'sleeping mode' and 'wake up' mode when there isno data traffic and normally this repetition cycles is much shorter than DCH FACH PCH cycles. This kind of 'sleeping' and 'wake up' cycles are called DTX, DRX. If you apply all these techniquest described above in wise combination, you would achieve such a status asi) Users feels like they are continuously connected to the network (User experience very short latency as if it isalways connected).ii) Even with this kind of user experience, energy consumption (current consumption) on UE can be minimized


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All the combination of this technique to achieve such a user experience is called "CPC". It means CPC is a collectiveterminoloty for a set of technologies, not any specific single technology. It implies that to understand CPC requires alot of efforts -:) Just in short, CPC is a combined technology of all of the following features.

UL-DTXDL-DRXHS-SCCH orders

HS-SCCH-lessNew UL-DPCCH slot format #4Cell DCH using E-DCH/HS-DSCHSRBs mapped on E-DCH/HS-DSCH with use of F-DPCH

CQI CQI stands for Channel Quality Indicator. As the name implies, it is an indicator carrying the information on howgood/bad the communication channel quality i s. This CQI is for HSDPA. (LTE also has CQI for its own purpose). CQI is the information that UE sends to the network and practically it implies the following twoi) Current Communication Channel Quality is this-and-that..

ii) I (UE) wants to get the data with this-and-that transport block size, which in turn can be directly converted intothroughput In HSDPA, the CQI value ranges from 0 ~ 30. 30 indicates the best channel quality and 0,1 indicates the poorestchannel quality. Depending which value UE reports, network transmit data with different transport block size. If network gets high CQI value from UE, it transmit the data with larger transport block size and vice versa. What if network sends a large transport block even though UE reports low CQI, it is highly probable that UE failed todecode it (cause CRC error on UE side) and UE send NACK to network and the network have to retransmit it which inturn cause waste of radio resources. What if UE report high CQI even when the real channel quality is poor ? In this case, network would send a largetransport block size according to the CQI value and it would become highly probable that UE failed to decode it(cause CRC error on UE side) and UE send NACK to network and the network have to retransmit it which in turncause waste of radio resources. How UE can measure CQI ? This is the most unclear topic to me. As far as I know, there is no explicit description inany standard on the mechanism by which the CQI is calculated, but it is pretty obvious that the following factors playimportant roles to CQI measurement.

signal-to-noise ratio (SNR)signal-to-interference plus noise ratio (SINR)signal-to-noise plus distortion ratio (SNDR)

It is unclear how these factors are used and whether there i s any other factors being involved. I was told the detailedCQI measurement algorithm is up UE implementation (chipset implementation). Regarding the influce of CQI on total throughput, refer to CQI vs Throughput in " Throughput " page.

Compressed Mode Before the handover, UE normally measure the cell power (signal quality) of the target cell andreport it to the network, so that network can make a decision whether to allow UE to handover tothe target cell or not.It is not a big issue to measure the signal quality of the target cell if the target cell is at thesame frequency as the current cell (Intrafrequency measurement). But there would be an issue whenthe target cell is at a different frequency from the current cell (Interfrequency measurement).Just in terms of logical sense of view, the simplest solution for Interfrequency measurement, thesimplest solution for this would be to implement two RF tranciever on UE. However, there are somepractical problems with this kind of two tranciever solution. One of the problems is cost issue. Itwould require additional cost to implement the additional tranciever. The other problem would be


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the possible interference between the current frequency and target frequency especially when thecurrent frequency and target frequency are close to each other. So they come out with a special techique called "Compressed Mode". The idea of the compressed modeis to create a small gap during which no transmission and reception happens. since there is nosignal transmission and reception during the gap, UE can switch to the target cell and perform thesignal quality measurement and come back to the current cell.To make this work seamlessly, there should be a well established agreement between UE and Networkabout the gap definition (e.g, Starting Position of the Gap, Gap length, number of Gaps etc) andthis agreement is established by a couple of RRC messages (e.g, Measurement Control, Physical

Channel Reconfiguration etc) as follows.

| | +-modeSpecificInfo ::= CHOICE [fdd] | | | +-fdd ::= SEQUENCE [011] | | | +-defaultDPCH-OffsetValue ::= INTEGER OPTIONAL:Omit | | | +-dpch-CompressedModeInfo ::= SEQUENCE OPTIONAL:Exist | | | | +-tgp-SequenceList ::= SEQUENCE OF SIZE(1..maxTGPS[6]) [1] | | | | +-TGP-Sequence ::= SEQUENCE [1] | | | | +-tgpsi ::= INTEGER (1..maxTGPS[6]) [1] | | | | +-tgps-Status ::= CHOICE [activate] | | | | | +-activate ::= SEQUENCE | | | | | +-tgcfn ::= INTEGER (0..255) [0] | | | | +-tgps-ConfigurationParams ::= SEQUENCE [000000] OPTIONAL:Exist | | | | +-tgmp ::= ENUMERATED [fdd-Measurement] | | | | +-tgprc ::= INTEGER (0..511) [0] | | | | +-tgsn ::= INTEGER (0..14) [4] | | | | +-tgl1 ::= INTEGER (1..14) [7] | | | | +-tgl2 ::= INTEGER OPTIONAL:Omit | | | | +-tgd ::= INTEGER (15..270) [270] | | | | +-tgpl1 ::= INTEGER (1..144) [12] | | | | +-dummy ::= INTEGER OPTIONAL:Omit | | | | +-rpp ::= ENUMERATED [mode0] | | | | +-itp ::= ENUMERATED [mode0] | | | | +-ul-DL-Mode ::= CHOICE [ul-and-dl] | | | | | +-ul-and-dl ::= SEQUENCE | | | | | +-ul ::= ENUMERATED [sf-2] | | | | | +-dl ::= ENUMERATED [higherLayerScheduling] | | | | +-dl-FrameType ::= ENUMERATED [dl-FrameTypeA]

| | | | +-deltaSIR1 ::= INTEGER (0..30) [10] | | | | +-deltaSIRAfter1 ::= INTEGER (0..30) [5] | | | | +-deltaSIR2 ::= INTEGER OPTIONAL:Omit | | | | +-deltaSIRAfter2 ::= INTEGER OPTIONAL:Omit | | | | +-nidentifyAbort ::= INTEGER OPTIONAL:Omit | | | | +-treconfirmAbort ::= INTEGER OPTIONAL:Omit Let's look into the definition of each parameters used about Compressed Mode.

Parameter Description

TGSN Transmission Gap Starting Slot NumberTGL1 Transmission Gap Length 1TGL2 Transmission Gap Length 2TGD Transmission Gap DistanceTGPL1 Transmission Gap Pattern Length 1TGPL2 Transmission Gap Pattern Length 2TGPRC Transmission Gap Repetition CountTGCFN Transmission Gap Connection Frame Number


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Constellation (Downlink)- Conceptual If you combine the following three sections in 25.213, you will have a overall downlink physical channel flow asshown below.

5.1 Spreading (Figure 8)5.1.5 Channel combining (Figure 9)5.3.2 Modulation (Figure 11)

Assuming the all the physical channel for data transfer is using QPSK (Release 99), the constellation is shown asbelow. (Graph on left shows Code Domain Power for each channel and the r ight side graph shows the constellation).


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When I first saw this constellation, I was very confused because it i s so much different from my expectation of QPSKconstellation.This kind of complicated constallation comes from the vector summation of multiple QPSK with different amplitudes.If only one channel is transmitted, you would have a normal QPSK constellation as you expected, but if multiplechannel (multiple QPSK) are summed, you would get various different patters depending on how many channels aresummed and what is the amplitude of each QPSK channel. Assuming there is just two QPSK channels are being transmitted, I created two example cases with two differentamplitude combination as follows.

Following sequence of graph show you how each of the constellation spot at the final result can created from twooriginal QPSK constellation.


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CPICH Ec/Io measurement report mapping RRC Connection Request and some Measurement Report message carries the CPICH measured value as follows. Butthe value itself is not a dB or dBm value. There is a predefined table that maps this value to the real dBm value.

+-rrcConnectionRequest ::= SEQUENCE [11]


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+-initialUE-Identity ::= CHOICE [tmsi-and-LAI] +-establishmentCause ::= ENUMERATED [registration] +-protocolErrorIndicator ::= ENUMERATED [noError] +-measuredResultsOnRACH ::= SEQUENCE [0] OPTIONAL:Exist | +-currentCell ::= SEQUENCE | | +-modeSpecificInfo ::= CHOICE [fdd] | | +-fdd ::= SEQUENCE | | +-measurementQuantity ::= CHOICE [cpich-Ec-N0] | | +-cpich-Ec-N0 ::= INTEGER (0..63) [41]

Following table comes from 3GPP 25.133.

Downlink Frame Timing Once you complete the cell search process described above, UE can figure out the following information about thetiming.i) Exact phase reference for downlink channels from CPICH (This is not the timing parameter, but this would veryimportant factors to decode other channels including Timing/Sync related channels).ii) Exact start timing of each slots from P-SCHiii) Exact start timing of each frame from S-SCHiv) System Frame Number for each frame from P-CCPCH (MIB) Once UE get all the information li sted above, the timing for other channels can be deduced by the following diagram(This diagram came from 3GPP TS 25.211). For example, S-CCPCH is transmitted at the multiples of 256 chips delayfrom the start of CPICH(Start of frame timing). And PICH is transmitted at the specified timing before S-CCPCH. For the details of these timing value, refer to 25.211 - 7 Timing relationship between physical channels - 7.1General Some of these timing offsets are set by higher layer signaling message (e.g, SIB, RRC Connection Setup, RadioBearer Setup). S-CCPCH TimingOffset is specified by SIB5 elements : sCCPCH-SystemInformationList.SCCPCH-SystemInformation[0].secondaryCCPCH-Info.modeSpecificInfo.fdd.timingOffset


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DRX/DTX DRX stands for "Discontinous Reception" and DTX stands for "Discontinous Transmission". When you are talkingabout 'Reception' and 'Transmission', you may often get confused with 'direction of data flow'. Is it from 'UE toNetwork' or 'Network to UE'. At least, I got confused so often with this.So let's make it clear about 'who is receiving ?' and 'who is transmitting' when we are talking about DRX and DTX.The answer is 'UE'. Therefore, DRX means 'Discontinous Reception by UE' and DTX means 'Discontinous Transmissionby UE'. Then what does it mean by 'Discontinous' ? To get clear understanding of this word, let's think about 'what does itmean by 'continous' ?'. 'Continous' is a ordinary mode of operation in most of the situation where we use mobilephone. Does 'Continous' mean that UE is continously (always) receiving some data and is continously (always)transmitting data ? No, it does not. UE cannot receive any data when Network does not send any data to it and UEcannot transmit any data when it does not have any data to send. 'Continuous transmission/Continuous Reception' inthis context mean that 'UE is continuously (always) ready to recieve data and is continously (always) ready totransmit the data. To be ready to recieve/transmit something, UE should be 'ON'. So Continous reception/Continous transmission meansthat "UE is always ON(Wake-up mode)".What's wrong with UE being always 'ON'. You many easily figure out that it will cause a lot of battery consumption.To save this kind of battery consumption, they invented a special mechanism called 'DiscontinousReception/Transmission'. 'Discontinous Transmission' and 'Discontinous Reception' means that UE is in Sleeping Modemost of the time and only periodically 'Wake up' to receive or transmit the data. Overall concept would sound simple, but you may get confiused again trying to understand the detailed parameterrelated to DTX and DRX. These parameters are specified in Radio Bearer Message as follows.First I thought we only need 'Periodicity of DTX/DRX' and 'Duration of ON time', but there are many other

parameters are involved. | +-dtx-drx-TimingInfo ::= SEQUENCE OPTIONAL:Exist

| | +-timing ::= CHOICE [newTiming] | | +-newTiming ::= SEQUENCE | | +-enablingDelay ::= ENUMERATED [radio-frames-0] | | +-ue-dtx-drx-Offset ::= INTEGER (0..159) [0] | +-dtx-drx-Info ::= SEQUENCE [11] OPTIONAL:Exist | | +-dtx-Info ::= SEQUENCE [01] OPTIONAL:Exist | | | +-e-dch-TTI-Length ::= CHOICE [dtx-e-dch-TTI-10ms] | | | | +-dtx-e-dch-TTI-10ms ::= SEQUENCE | | | | +-ue-dtx-Cycle1-10ms ::= ENUMERATED [sub-frames-10] | | | | +-ue-dtx-Cycle2-10ms ::= ENUMERATED [sub-frames-20] | | | | +-mac-dtx-Cycle-10ms ::= ENUMERATED [sub-frames-10]


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| | | +-ue-dtx-cycle2InactivityThreshold ::= ENUMERATED [e-dch-tti-8] | | | +-ue-dtx-cycle2DefaultSG ::= INTEGER OPTIONAL:Omit | | | +-ue-dtx-long-preamble-length ::= ENUMERATED [slots-4] OPTIONAL:Exist | | | +-mac-InactivityThreshold ::= ENUMERATED [e-dch-tti-8] | | | +-cqi-dtx-Timer ::= ENUMERATED [sub-frames-32] | | | +-ue-dpcch-Burst1 ::= ENUMERATED [sub-frames-1] | | | +-ue-dpcch-Burst2 ::= ENUMERATED [sub-frames-1] | | +-drx-Info ::= SEQUENCE OPTIONAL:Exist | | | +-ue-drx-Cycle ::= ENUMERATED [sub-frames-10] | | | +-ue-drx-Cycle-InactivityThreshold ::= ENUMERATED [sub-frames-32]

| | | +-ue-GrantMonitoring-InactivityThreshold ::= ENUMERATED [e-dch-tti-8] | | | +-ue-drx-GrantMonitoring ::= BOOLEAN [TRUE] | | +-uplink-DPCCHSlotFormatInformation ::= ENUMERATED [slot-format-1] Now let's look into the detailed parameters. Let's think about DTX part first. (I will draw some diagram later when Ihave more time, but now I will just describe it verbally). The most important parameters for DTX are as follows.

| | | +-e-dch-TTI-Length ::= CHOICE [dtx-e-dch-TTI-10ms] | | | | +-dtx-e-dch-TTI-10ms ::= SEQUENCE | | | | +-ue-dtx-Cycle1-10ms ::= ENUMERATED [sub-frames-10] | | | | +-ue-dtx-Cycle2-10ms ::= ENUMERATED [sub-frames-20] | | | | +-mac-dtx-Cycle-10ms ::= ENUMERATED [sub-frames-10] First think about the cycles first. You see three different cycles here. In this example, we have the following threecycles. ue-dtx-Cycle1-10ms ::= ENUMERATED [sub-frames-10] = 20 ms (2 ms/subframe x 10 subframe)ue-dtx-Cycle2-10ms ::= ENUMERATED [sub-frames-20] = 40 ms (2 ms/subframe x 20 subframe)mac-dtx-Cycle-10ms ::= ENUMERATED [sub-frames-10] = 20 ms(2 ms/subframe x 10 subframe) The overall procedure of DTX operation goes as follows.i) UE get's into sleeping mode and ue-dtx-Cycle1-10ms startsii) UE wake up when ue-dtx-Cycle1-10ms expires and stay up for a 'ON-duration'.iii) If there is no E-DCH frame to be transmitted and ue-dtx-Cycle1-10ms is expired, it will get into sleeping modeand ue-dtx-Cycle2-10ms timer starts.iv) UE wake up when ue-dtx-Cycle2-10ms timer expires and stay up for 'ON-duration'.v) If there is no E-DCH frame to be transmitted and ue-dtx-Cycle1-10ms is expired, it will get into sleeping modeand ue-dtx-Cycle1-10ms timer starts.vi) repeat the step step ii)~v).

The question is when UE wake up, how long it should stay 'up' ? In another words, how the 'ON time' is determined.The 'ON time' is determined by e-dch-TTI-Length ::= CHOICE [dtx-e-dch-TTI-10ms]. In this example, the ON time is10 ms. One thing you notice is that ue-dtx-Cycle1-10ms and ue-dtx-Cycle2-10ms is alternating here. In the procedure described above, we only mentioned about ue-dtx-Cycle1 and ue-dtx-Cycle2 . Then what is the'mac-DTX-Cycle ' ? Simply put this is DTX cycle timer with the highest priori ty. In other words, even though UE wouldbe in 'sleep mode' according to ue-dtx-Cycle1-10ms and ue-dtx-Cycle2-10ms, if i t gets into 'ON period' of mac-dtx-Cycle-10ms, it should wake up right away and transmit the data. Pretty complicated, right ? But it is even more complicated when it is really working on in real environment since wehave to consider some additional factors as well. The only way for you to understand this is to collect as much

example as possible to show you very diverse situation of DTX. Here goes one example, but I will keep adding moreexamples later.


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Now let's look into DRX operation. The DRX cycle is specified as shown below. It seems a little bit simpler than DTXcycle configuration.

| | +-drx-Info ::= SEQUENCE OPTIONAL:Exist | | | +-ue-drx-Cycle ::= ENUMERATED [sub-frames-10] | | | +-ue-drx-Cycle-InactivityThreshold ::= ENUMERATED [sub-frames-32] The overall procedure is as follows.i) UE gets into sleeping mode.ii) UE wakes up when ue-drx-Cycle starts and stay up for one HS-PDSCH TTI.

iii.a) If there is no HS-PDSCH data for the UE during the 'ON time', it gets into sleeping mode.iii.b) If there is HS-PDSCH data for the UE during the 'ON time', UE continue to stay on for the duration of ue-drx-Cycle-InactivityThreshold.iii.c) if there is another HS-PDSCH data for the duration of of ue-drx-Cycle-InactivityThreshold, ON-time getextended for another ue-drx-Cycle-InactivityThreshold from the reception of the data.iii.d) repeat step iii.a)~iii.c)iv) repeat the steps ii)~iii) You may think 'why UE need to go through such a complicated process described in the step iii ?'. Logic is simple. If UE receives a data during the short period of 'ON-time', it is highly probably that there is another data coming rightnext TTI. So instead of getting into the sleeping mode right away just according to ue-drx-Cycle, it stay awake a littlebit more not to cause too much delay for the downlink traffic.

E-DPCCH As DPCCH carries the information required to decode DPDCH in R99, E-DPCCH carries the information required todecode E-DPDCH in HSUPA. E-DPCCH carries 10 bits structured as follows.

E-TFCI (7 bits) RSN (2 bits) Happy bit (1 bit)

E-TFCI : It stands for "E-DCH Transport Format Combination Indicator" and indicates the transport format beingtransmitted simultaneously on E-DPDCHs. The E-TFCI tells the receiver the transport block size coded on theE-DPDCH. From this value, the reciever (Node B) can figure out how many E-DPDCHs are transmitted in parallel andwhat spreading factor is used. RSN : It stands for Retransmission Sequence Number meaning as follows :


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00 : New Transmission01 : First Retransmission10 : Second Retransmission11 : Higher than Second Retransmission

Happy bit : It carries the information whether the UE is content with the current data rate (Grant) allocated by thenetwork or not.

E-TFCI Selection

Frequency Table


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HARQ - HSDPA

HARQ - HSUPA Uses Synchronous HARQThe terminal should keep the unacknowledged data in the memory for any possible retransmissionBoth Soft(Chasing) combining and Incremental Redundancy can be applicable. < 10 ms TTI >Max 4 HARQ Process are being used.

< 2 ms TTI >


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Max 8 HARQ Process are being used.

HSDPA Category Table Following Table comes from TS 25.306.


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HSUPA Category Table

HSUPAcategory

Maximumnumber of

HSUPAcodes

transmitted

Minimumspreading

factor

Supportfor 10 and 2 ms

HSUPA TTI

Maximumnumber of

bitstransmitted

withina 10 msHSUPA

TTI

Maximumnumber of

bitstransmitted

withina 2 msHSUPA

TTI

MaximumBit rate

Category 1 1 SF4 10 ms TTI only 7296 - 0.73 MbpsCategory 2 2 SF4 10 ms and 2 ms TTI 14592 2919 1.46 MbpsCategory 3 2 SF4 10 ms TTI only 14592 - 1.46 MbpsCategory 4 2 SF2 10 ms and 2 ms TTI 20000 5837 2.92 MbpsCategory 5 2 SF2 10 ms TTI only 20000 - 2.00 MbpsCategory 6 4 SF2 10 ms and 2 ms TTI 20000 11520 5.76 Mbps

HSUPA - UL Grant/E-AGCH,E-RGCH In HSDPA case, data source is NodeB and destination is UE. Since Network (the data source) is the master and it hasall the authorities for data transmission scheduling, it doesn't need any Grant ("approval for data transmission").Basically Network can transmit the data anytime it is ready. But in HSUPA case the situation is different . The data


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source is UE and Network is data sinc(reciever), but UE is not the master of the scheduling. Network is schedulingmaster all the time. It means that in HSUPA, the transmitter (UE in this case) has to have "approval fortransmission" from the data reciever (Network in this case). The "Approval for transmission" is called "UL Grant", andoverall mechanism for UL Grant and data transmission in HSUPA goes as follows.As you see, there are two different types of UL Grant called "Absolute Grant" carried by AGCH(Absolute GrantChannel) and "Relative Grant" carried by RGCH(Relative Grant Channel).Absolute Grant is being transmitted by the network every TTI and it is transmitted to the all UE communicating tothe network.Relative Grant can be transmitted only at the TTI in which PHICH is not transmitted.

The value for the Absolute Grant can be 0 ~ 31. Except the value 0~1. All the remaining value is mapped to acertain level of power value that UE can use for data transmission. (At the beginning, I was so confused about thisvalue. When we say "Grant", I expected each of the value would mean "Yes, you can transmit the data and this i sthe data rate you can transmit". But what I see from the following Absolute Grant table is "Here is the amount of power you can use for the data transmission".Then you may ask "Is there any predefined algorithm running on UE side which maps this power value to the realdata rate ?".Excellent question ! Yes, there is. UE is performing a special E-TFCI selection algorithm based on how much power itcan use for data transmission and this Grant value determines "how much power is available for the datatransmission". Following is Absolute Grant table from 25.212 v9.4.0.


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Now let's look into the Relative Grant. Relative Grant carries three different status (Command), UP, HOLD, DOWN

and the meaning of this command is defined in 25.212 as follows.

Location Updating Reject This is a NAS message which is sent to UE when the UE is not allowed to register to the specific network or a specific

Location Area. < Cause #11 - PLMN not allowed > Network send this message when a UE tries to camp on the PLMN (usually VPLMN) which is not allowed for the UE.When it recieves, UE has to do following steps.

i) UE has to store this PLMN in forbidden PLMN list in USIM

UE has to remove this PLMN from 'forbidden LPLMN' list in the following cases.

i) UE is switched off ii) USIM is removediii) User select the PLMN in Manual Selection Mode and it gets accepted by the network.


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< Cause #12 - LA not allowed > When a UE have a regionally restricted service where it can only obtain service on certain LAs and it attempts tocamp on a cell of an LA for which it does not have service entitlement, it recieves the Location Update Reject withCause #12. When it recieves, UE has to do following steps.

i) UE has to store this LAI in the 'forbidden LAs for regional provision of service' list in UE so that it would notkeep retrying the location updating process.ii) UE gets into 'Limited Service' state.

iii) UE initiate Cell Selection Process

UE has to remove this LAI from 'forbidden LAs for regional provision of service' list in the following cases.

i) UE is switched off ii) USIM is removed

< Cause #13 - roaming not allowed in this LA > When a UE recieves the Location Update Reject with Cause #13, UE has to do following steps.

i) UE has to store this LAI in the 'forbidden LAs for roaming' list in UE so that it would not keep retrying thelocation updating process.ii) UE has to initiate PLMN selection process (not Cell Selection Process).

< Cause #15 - No Suitable Cell s In LA > When a UE recieves the Location Update Reject with Cause #15, UE has to do following steps.

i) UE has to store this LAI in the 'forbidden LAs for roaming' list in UE so that it would not keep retrying thelocation updating process.ii) UE has to searches for a suitable cell in the same PLMN but belonging to an LA which is not in the forbiddenLAs for roaming list

Measurement Control and Handover

I got a question long time ago, saying "Why we see measurement control/measurement report almost always inHandover procedure ?" In real l ive network, it would be common to perform 'Measurement Control' both for SHO and HHO. But purely interms of technology, 'Measurement Control' and 'Measurement Report' is not a mandatory part for any Handoverprocess. If I explain these two procedure in a very simplified (a l ittle bit over simplified) manner, I would say i) Handover - Changing a communication cell from one to another, or changing the number of communication cell toone to another.ii) Measurement Control - Ordering UE to perform a specific measurement (e.g, the signal quality of the current cellor the signal quality of another cell). Basically these two procedures are independent.

But in reality, most of network operator combine these two process mainly to improve the successbility of thehandover. For example, let's suppose that there are two cells (let's call them Cell A, Cell B respectively) and a UE is nowcommunicating to cell A and now your network is trying to let UE change the communication cell from Cell A to CellB. The simplest way would be to send UE a handover command, saying "change Cell from A to B". But what if the cellB is not ready to communicate with your UE. For example, the signal quality between Cell A and UE is so bad and itwill almost for sure that the call would drop as soon as the UE changes the cell ? Do you still want to change the cell ?The answer would be No. Main for this kind of reason, the network try to make it sure that the target cell (the UE is handed over to) is goodenough condition before trying handover. That's why in most live network log, you would see measurement


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control/measurement report message before the handover.

P-CCPCH RSCP measurement report mapping Following Table is from 3GPP 25.331

PRACH Power Initial PRACH (The first PRACH that UE transmit) is determined by the following formula. Initial RACH Preamble Power = Primary CPICH TX Power CPICH_RSCP + UL_Interference + Constant Value CPICH_RSCP is the power directly measured by UE and all other parameters are calculated (obtained) from systeminformation. The related parameter and system information is as follows.

System Information Information Element Example Value

SIB3 Maximum Allowed UL Tx Power 21 dBm

SIB5

Primary CPICH Power -8 dBmPower Ramp Step 3 dBMmax 2NB01min 10NB02max 10

SIB7 UL Interference -92 If UE fail to get AICH for the PRACH, it increment the PRACH power by Power Ramp Step (SIB5) and transmit thePRACH again. UE repeat this process until it gets AICH or it retried the specific number specified in SIB5.Following screenshot is an example of PRACH transmission and retransmission. This is from a test resultl of 34.1218.4.2.1. In this test case, Network intentionally does not send AICH so that UE keep sending PRACH with specifiedpower increment in the specified number of times.


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RRC Establishment Cause Every RRC Connection Request message has its own establishmentCause and understanding the exact meaning of each of these establishment cause would help you with troubleshooting in many cases. In ASN definition, it has along list of establishmentcause as follows.


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You would have to surf through many different specification to find the descriptions for all of these causes, but youwould find a list of the most commonly used establishmentcause from the following table defined in 24.008.


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RSSI measurement report mapping Following table comes from 25.133.

TFI and TFCI TFI stands for Transport Format Indicator TFCI stands for Transport Format Combination Indicator. As you see in thefollowing diagram each Transport Block has one TFI attached to it. In physical layer, multiple transport blocks arecombined into a large 'transmission frame'. This combined transmission frame is called Coded Composite TransportChannel (CCTrCh). Each CCTrCH frame gets its own indicator which is called TFCI.


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TFI plays roles as follows.

The TFI is a label for a specific transport format within a transport format set.It is used in the inter-layer communication between MAC and L1 each time a transport block set is exchangedbetween the two layers on a transport channel.When the DSCH is associated with a DCH, the TFI of the DSCH also indicates the physical channel (i.e. thechannelisation code) of the DSCH that has to be l istened by a UE

TFCI plays roles as follows.

This is a representation of the current Transport Format Combination.The TFCI is used in order to inform the receiving side of the currently valid Transport Format Combination, andhence how to decode, de-multiplex and deliver the received data on the appropriate Transport Channels.

There is a one-to-one correspondence between a certain value of the TFCI and a certain Transport FormatCombination.MAC indicates the TFI to Layer 1 at each delivery of Transport Block Sets on each Transport Channel. Layer 1then builds the TFCI from the TFIs of all parallel transport channels of the UE, processes the Transport Blocksappropriately and appends the TFCI to the physical control signalling.Through the detection of the TFCI the receiving side is able to identify the Transport Format Combination.

Scrambling Code Let's suppose you are a NodeB. You will getting various signals from many different users (UEs) all at the same time.Then how would you differentiate the incoming signals into separate users at the very low level of your hardware ?.Of course you can figure out exactly which user you are dealing with at higher layer with various type of user ID (UEID), but my question is how to figure out each user at PHY layer ? Now let's assume that you are a UE. You may be hearing many signals from multiple NodeBs simultaneously. Thenhow would you differentiate the incoming signals into separate NodeB at the very low level of your hardware ? The answer to both of the question is same. It is "Scrambling Code". By using the scrambling code, NodeB canseparate signals coming simultaneously from many different UEs and UE can separate signals coming simultaneouslyfrom many different NodeB. Now let's look into how/where the scrambling code works. Following illustration shows the procedure about the dataprocessing in physical layer. As you see in the following diagram, "Scrambling" happens at the chip rate of the signalprocessing. Since the chip rate of the scrambling code is the same as the chip rate of the chanelization codescrambling does not change the signal data rate.


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A specific bit sequence which is used for scrambling is called 'Scrambling code'. There are two types of scrambling codes : long scrambling code and short scrambling code. Long scramblingcode(38400 chips) derived from Gold codes and short codes (256 chips) derived from S(2) codes.Then which type of scrambling code we use ?.In downlink, only long codes are used.In uplink direction long codes are used for node B using Rake reciever and short codes are used for NodeB usingmultiuser detection or interference cancellation recievers. With short codes the implementation of cyclic processingstructure is simpler. Even though main role of the scrambling code is to separate multiple signals into the one from each transmitter, ithas several additional side effect (I mean 'good side effect').

It can improve Synchronization. The scrambling code is designed to have relatively high auto-correlation propertyand you can use the result of high-auto correlation to tune the synchronization timing. It enables you to reuse the spreading code. Spreading code is used to match the bit rate data into chip rate (3.84Mcps) signal and also for separating one specific channel from another. For this separation, it uses a special set of spreading code which has the orthogonal to each member of the set. This set of spreading code being used inWCDMA is called VLSF (Variable Length Spreading Factor). But the number of VLSF is not infinite. We only have afinite number of VLSF codes which may put us in short of those codes.If two different data stream uses the same VLSF codes, the receive cannot differentiate these two. But if the twochannels are using different scrambling codes even though they are using the same spreading code, the two data canbe separated. The two data stream will go to different reciever path by scrambling process (unscrambling processmore accurately speaking).

Now let's look into the further details of how the scrambling process is really implemented. Here, I will just give youthe diagram for each case and the 3GPP specification where you can have further details. First, let's look into PRACH scrambling part. The overall flow is as foll ows.


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For the details of PRACH Preamble part of scrambling code, refer to 25.213, section 4.3.3.2 Preamble scramblingcode.For the details of PRACH message part of scrambling code, refer to 25.213, section , 4.3.2.5 PRACH message partscrambling code How UE would know which scrambling code it has to use for PRACH ? That information is carried by SIB5 as follows(see the IE marked in red) SysInfoType5 ::= SEQUENCE [000] +-sib6indicator ::= BOOLEAN [FALSE] +-pich-PowerOffset ::= INTEGER (-10..5) [-5] +-modeSpecificInfo ::= CHOICE [fdd] | +-fdd ::= SEQUENCE | +-aich-PowerOffset ::= INTEGER (-22..5) [5] +-primaryCCPCH-Info ::= CHOICE OPTIONAL:Omit +-prach-SystemInformationList ::= SEQUENCE OF SIZE(1..maxPRACH[16]) [1] | +-PRACH-SystemInformation ::= SEQUENCE [11101] | +-prach-RACH-Info ::= SEQUENCE | | +-modeSpecificInfo ::= CHOICE [fdd] | | +-fdd ::= SEQUENCE | | +-availableSignatures ::= BIT STRING [1111111111111111] | | +-availableSF ::= ENUMERATED [sfpr64] | | +-preambleScramblingCodeWordNumber ::= INTEGER (0..15) [0] | | +-puncturingLimit ::= ENUMERATED [pl1] | | +-availableSubChannelNumbers ::= BIT STRING [111111111111] First, let's look into scrambling process of all other UL channels except PRACH. The overall flow is as follows.

For the details of UL DPCH part of scrambling code, refer to 25.213, section 4.3.2.4 Dedicated physical channelsscrambling code. How UE would know which scrambling code it has to use for PRACH ?This code is determined by the network and informed to UE by rrc Connection Setup and Radio Bearer Setup


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message as follows. DL-CCCH-Message ::= SEQUENCE [0] +-integrityCheckInfo ::= SEQUENCE OPTIONAL:Omit +-message ::= CHOICE [rrcConnectionSetup] +-rrcConnectionSetup ::= CHOICE [r3] +-r3 ::= SEQUENCE [0] +-rrcConnectionSetup-r3 ::= SEQUENCE [0011100111] | | +-ul-ChannelRequirement ::= CHOICE [ul-DPCH-Info] OPTIONAL:Exist

| | +-ul-DPCH-Info ::= SEQUENCE [1] | | +-ul-DPCH-PowerControlInfo ::= CHOICE [fdd] OPTIONAL:Exist | | | +-fdd ::= SEQUENCE | | | +-dpcch-PowerOffset ::= INTEGER (-82..-3) [-30] | | | +-pc-Preamble ::= INTEGER (0..7) [0] | | | +-sRB-delay ::= INTEGER (0..7) [7] | | | +-powerControlAlgorithm ::= CHOICE [algorithm1] | | | +-algorithm1 ::= INTEGER (0..1) [0] | | +-modeSpecificInfo ::= CHOICE [fdd] | | +-fdd ::= SEQUENCE [00] | | +-scramblingCodeType ::= ENUMERATED [longSC] | | +-scramblingCode ::= INTEGER (0..16777215) [0] | | +-numberOfDPDCH ::= INTEGER OPTIONAL:Omit | | +-spreadingFactor ::= ENUMERATED [sf64] | | +-tfci-Existence ::= BOOLEAN [TRUE] | | +-numberOfFBI-Bits ::= INTEGER OPTIONAL:Omit | | +-puncturingLimit ::= ENUMERATED [pl1] RRC:DL-DCCH-MessageDL-DCCH-Message ::= SEQUENCE [0] +-integrityCheckInfo ::= SEQUENCE OPTIONAL:Omit +-message ::= CHOICE [radioBearerSetup] +-radioBearerSetup ::= CHOICE [r3] +-r3 ::= SEQUENCE [0] +-radioBearerSetup-r3 ::= SEQUENCE [001001000100101010100111] | | +-ul-ChannelRequirement ::= CHOICE [ul-DPCH-Info] OPTIONAL:Exist | | +-ul-DPCH-Info ::= SEQUENCE [1] | | +-ul-DPCH-PowerControlInfo ::= CHOICE [fdd] OPTIONAL:Exist

| | | +-fdd ::= SEQUENCE | | | +-dpcch-PowerOffset ::= INTEGER (-82..-3) [-30] | | | +-pc-Preamble ::= INTEGER (0..7) [0] | | | +-sRB-delay ::= INTEGER (0..7) [7] | | | +-powerControlAlgorithm ::= CHOICE [algorithm1] | | | +-algorithm1 ::= INTEGER (0..1) [0] | | +-modeSpecificInfo ::= CHOICE [fdd] | | +-fdd ::= SEQUENCE [10] | | +-scramblingCodeType ::= ENUMERATED [longSC] | | +-scramblingCode ::= INTEGER (0..16777215) [0] | | +-numberOfDPDCH ::= INTEGER (1..maxDPDCH-UL[6]) [1] OPTIONAL:Exist | | +-spreadingFactor ::= ENUMERATED [sf64] | | +-tfci-Existence ::= BOOLEAN [TRUE] | | +-numberOfFBI-Bits ::= INTEGER OPTIONAL:Omit | | +-puncturingLimit ::= ENUMERATED [pl0-84] First, let's look into scrambling process of all DL channels. The overall flow is as follows.


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For the details of DL channels of scrambling code, refer to 25.213, section 5.1.4 Scrambling DL-CCCH-Message ::= SEQUENCE [0] +-integrityCheckInfo ::= SEQUENCE OPTIONAL:Omit +-message ::= CHOICE [rrcConnectionSetup] +-rrcConnectionSetup ::= CHOICE [r3] +-r3 ::= SEQUENCE [0]

+-rrcConnectionSetup-r3 ::= SEQUENCE [0011100111] | | +-dl-InformationPerRL-List ::= SEQUENCE OF SIZE(1..maxRL[8]) [1] OPTIONAL:Exist | +-DL-InformationPerRL ::= SEQUENCE [10] | +-modeSpecificInfo ::= CHOICE [fdd] | | +-fdd ::= SEQUENCE [00] | | +-primaryCPICH-Info ::= SEQUENCE | | | +-primaryScramblingCode ::= INTEGER (0..511) [9] | | +-dummy1 ::= SEQUENCE OPTIONAL:Omit | | +-dummy2 ::= SEQUENCE OPTIONAL:Omit | +-dl-DPCH-InfoPerRL ::= CHOICE [fdd] OPTIONAL:Exist | | +-fdd ::= SEQUENCE [000] | | +-pCPICH-UsageForChannelEst ::= ENUMERATED [mayBeUsed] | | +-dpch-FrameOffset ::= INTEGER (0..149) [0] | | +-secondaryCPICH-Info ::= SEQUENCE OPTIONAL:Omit | | +-dl-ChannelisationCodeList ::= SEQUENCE OF SIZE(1..maxDPCH-DLchan[8]) [1] | | | +-DL-ChannelisationCode ::= SEQUENCE [00] | | | +-secondaryScramblingCode ::= INTEGER OPTIONAL:Omit | | | +-sf-AndCodeNumber ::= CHOICE [sf128] | | | | +-sf128 ::= INTEGER (0..127) [30] | | | +-scramblingCodeChange ::= ENUMERATED OPTIONAL:Omit | | +-tpc-CombinationIndex ::= INTEGER (0..5) [0] | | +-dummy ::= ENUMERATED OPTIONAL:Omit | | +-closedLoopTimingAdjMode ::= ENUMERATED OPTIONAL:Omit | +-dummy ::= SEQUENCE OPTIONAL:Omit +-laterNonCriticalExtensions ::= SEQUENCE OPTIONAL:Omit RRC:DL-DCCH-MessageDL-DCCH-Message ::= SEQUENCE [0] +-integrityCheckInfo ::= SEQUENCE OPTIONAL:Omit +-message ::= CHOICE [radioBearerSetup] +-radioBearerSetup ::= CHOICE [r3] +-r3 ::= SEQUENCE [0] +-radioBearerSetup-r3 ::= SEQUENCE [001001000100101010100111] | | +-dl-InformationPerRL-List ::= SEQUENCE OF SIZE(1..maxRL[8]) [1] OPTIONAL:Exist | +-DL-InformationPerRL ::= SEQUENCE [10] | +-modeSpecificInfo ::= CHOICE [fdd] | | +-fdd ::= SEQUENCE [00] | | +-primaryCPICH-Info ::= SEQUENCE | | | +-primaryScramblingCode ::= INTEGER (0..511) [9] | | +-dummy1 ::= SEQUENCE OPTIONAL:Omit


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| | +-dummy2 ::= SEQUENCE OPTIONAL:Omit | +-dl-DPCH-InfoPerRL ::= CHOICE [fdd] OPTIONAL:Exist | | +-fdd ::= SEQUENCE [000] | | +-pCPICH-UsageForChannelEst ::= ENUMERATED [mayBeUsed] | | +-dpch-FrameOffset ::= INTEGER (0..149) [0] | | +-secondaryCPICH-Info ::= SEQUENCE OPTIONAL:Omit | | +-dl-ChannelisationCodeList ::= SEQUENCE OF SIZE(1..maxDPCH-DLchan[8]) [1] | | | +-DL-ChannelisationCode ::= SEQUENCE [00] | | | +-secondaryScramblingCode ::= INTEGER OPTIONAL:Omit | | | +-sf-AndCodeNumber ::= CHOICE [sf128]

| | | | +-sf128 ::= INTEGER (0..127) [5] | | | +-scramblingCodeChange ::= ENUMERATED OPTIONAL:Omit | | +-tpc-CombinationIndex ::= INTEGER (0..5) [0] | | +-dummy ::= ENUMERATED OPTIONAL:Omit | | +-closedLoopTimingAdjMode ::= ENUMERATED OPTIONAL:Omit | +-dummy ::= SEQUENCE OPTIONAL:Omit

Uplink Frame Timing In R99 (WCDMA) case, the only Uplink channel you have is PRACH and DPDCH/DPCCH, but PRACH is special casewhich will be described in detail in 'RACH Process' section. Here we only think about DPDCH/DPCCH. Uplink DPDCH/DPCCH timing is 1024 chips after DPDCH/DPCCH timing.

Quick Reference UMTS

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