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1 WCDMA RAN Protocols and Procedures Chapter 5 RLC and MAC Protocols.

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1 1 WCDMA RAN Protocols and Procedures Chapter 5 RLC and MAC Protocols

2 2 Objectives of Chapter 5, RLC and MAC Protocols After this chapter the participants will be able to: 1.Explain the RLC functions. 2.List the different modes of RLC (transparent, unacknowledged and acknowledged mode) and explain the structure of the Protocol Data Unit (PDU) involved in these cases. 3.Explain the MAC functions. 4.Explain the MAC architecture, its entities and their usage for the mapping of transport channels. 5.List the contents of the MAC Protocol Data Unit (PDU). 6.Explain the Transport Format selection and the relation between Combinations (TFC) and Sets (TFCS). 7.Explain Channel Type Switching. 8.Explain the structure and mapping of physical channels.

3 3 INTRODUCTION

4 4 Uu interface protocol architecture (figure 5-1) (1)

5 5 The control interfaces between the RRC and all the lower layer protocols are used by the RRC layer : * configure characteristics of the lower layer protocol entities, including parameters for the physical, transport and logical channels. * to command the lower layers to report measurement results and errors to the RRC. Uu interface protocol architecture (figure 5-1) (2)

6 6 RADIO LINK CONTROL (RLC) PROTOCOL -- INTRODUCTION--

7 7 INTRODUCTION The RLC work in transparent, unacknowledged and acknowledged mode. in the control plane, the service provided by the RLC layer is called Signalling Radio Bearer (SRB). In the user plane, the service provided by the RLC layer is called a Radio Bearer (RB)

8 8 Protocol Data Unit (PDU) and Service Data Unit (SDU) (1) (figure 5-2) SDU : Service Data Unit PDU : Protocol Data Unit PCI: Protocol Control Information Processing done for the SDUs at layer N can be e.g.: -Add overhead (e.g. sequence number, ch type info) -Segmentation, etc. PDCP PDCP PDU RLC RLC SDU RLC PCI RLC PDU MAC MAC SDU PDCP PDU RLC SDU RLC PDU MAC SDU Uu interface RLC PCI payload RLC PCI payload

9 9 the Radio Link Control (RLC) layer receives a PDCP PDU. In the RLC layer, the data will be known as an RLC SDU After the header is added, the data is called an RLC PDU In the Medium Access Layer (MAC) this is now a MAC SDU. The MAC layer may add a MAC header and send MAC PDUs to the physical layer. Protocol Data Unit (PDU) and Service Data Unit (SDU) (2)

10 10 RADIO LINK CONTROL (RLC) PROTOCOL -- RLC FUNCTIONS --

11 11 RLC Protocol Entity (1) RLC Services –L2 connection establishment and release –Transparent data transfer –Unacknowledged data transfer –Acknowledged data transfer RLC Functions –Segmentation and re-assembly –Concatenation –Padding –Transfer of user data in transparent, unacknowledged and acknowledged mode. –Error correction (ARQ) –In-sequence delivery –Duplicate detection –Flow control –Sequence number check –Ciphering

12 12 RLC Protocol Entity (2) 1. Segmentation and reassembly Performs segmentation/reassembly of variable length higher layer PDUs into/from smaller RLC Payload Units (PUs). 2. Concatenation If the contents of an RLC SDU do not fill an integral number of RLC PDUs, the first segment of the next RLC SDU may be put into the RLC PDU in concatenation with the last segment of the previous RLC SDU 3. Padding When concatenation is not applicable and the remaining data to be transmitted does not fill an entire RLC SDU of given size, the remainder of the data field is filled with padding bits. 4. Transfer of user data RLC supports acknowledged, unacknowledged and transparent data transfer. Transfer of user data is controlled by QoS setting.

13 13 RLC Protocol Entity (3)

14 14 RLC Protocol Entity (4)

15 15 RADIO LINK CONTROL (RLC) PROTOCOL -- RLC MODES --

16 16

17 17 RLC Layer Architecture (figure 5-3) Tx Tx/Rx Rx Tx Tx/Rx TM UM AM In Transparent and Unacknowledged Mode the RLC entities are unidirectional In Acknowledged Mode, it is bi-directional

18 18 RLC Transparent Mode PDU (figure 5-4) Data The RLC TM PDU introduces no overhead Protocol functions may still be applied e.g. segmentation TM is used for voice and circuit switched data where delay should be as low as possible. It is also used for the SRB for BCCH and PCCH.

19 19 RLC Transparent Mode Entities (figure 5-5) Transmitting TM- RLC entity Transmission buffer Segmentation TM-SAP CCCH/DCCH/DTCH/SHCCH– UE BCCH/PCCH/DCCH/DTCH– UTRAN Receiving TM- RLC entity Reception buffer Reassembly TM-SAP Radio Interface (Uu) CCCH/DCCH/DTCH/SHCCH– UTRAN BCCH/PCCH/DCCH/DTCH– UE UE/UTRAN UTRAN/UE

20 20 RLC Unacknowledged Mode PDU (figure 5-6) Oct1 E Length Indicator Data PAD Oct N E Length Indicator (Optional)... E Sequence Number (Optional) Sequence number. E: Extension bit. Indicates whether next octet will be a length indicator and E bit. Data shall be a multiple of 8 bits. If the transmitted data does not fill an entire PDU the remainder of the data field is filled with padding bits. Ciphering Unit no retransmission protocol is used and data delivery is not guaranteed. Received erroneous data is either marked or discarded depending on the configuration.

21 21 RLC Fields (table 5-1) length indicators Length Indicators are also used to define whether Padding is included in the UMD PDU. It may be 7 bits (if the largest PDU size is ≤ 125 octets) or 15 bits long (otherwise). some length indicator sequences are predefined

22 22 Predefined length indicators. (table 5-2)

23 23 RLC Unacknowledged Mode Entities (figure 5-7) Transmittin g UM RLC entity Transmission buffer UM-SAP Receiving UM RLC entity Reception buffer UM-SAP Radio Interface (Uu) Segmentation & Concatenation Ciphering Add RLC header Reassembly Deciphering Remove RLC header DCCH/DTCH– UE CCCH/SHCCH/DCCH/DTCH/CTCH– UTRAN DCCH/DTCH– UTRAN CCCH/SHCCH/DCCH/DTCH/CTCH– UE UE/UTRAN UTRAN/UE Segmentation & Concatenation Padding Ciphering Sequence number check Transfer of user data Example for UM RLC: The cell broadcast service is an example of a user service that could utilise UM as well as the RRC Connection Setup/Reject message sent on CCCH/FACH.

24 24 RLC Acknowledged Mode PDU (figure 5-8) Sequence Number D/C ELength Indicator Data PAD or a piggybacked STATUS PDU Oct1 2 OctN P HE ELength Indicator... (Optional) Oct3 (Optional) D/C: Data/Control PDU indicator bit P: Poll bit. To be used to request for a Status PDU. HE: Header Extension bits. Indicates if the next octet will be data or a length indicator and E bit. E: Extension bit. Indicates whether next octet will be a length indicator and E bit. Ciphering Unit Example for AM RLC: * for packet-type services such as Internet browsing and (DTCH). * also used for signalling, when it is important that the signalling is received correctly but delay is not the most important.

25 25 RLC fields (table 5-3 and 5-4) D/C field Length: 1bit. The D/C field indicates the type of an AM PDU. It can be either data or control PDU. BitDescription 0 Control PDU 1 Data PDU NOTE: There are some predefined sequence numbers

26 26 RLC Fields continued (table 5-5 and 5-6)

27 27 RLC fields continued (table 5-7) The Status PDU : is used for retransmission. The receiver transmits status reports to the sender in order to inform the sender about which AMD PDUs have been received and not received.

28 28 RLC PDU Formats- Status PDU (figure 5-9) D/C: Data/control PDU indicator. SUFI: Super Field. This field can be either a list, bitmap, relative bitmap, Acknowledgment field etc. Which type of field it is is indicated within the SUFI. Octet 1 Octet 2 Octet N D/CPDU typeSUFI 1 SUFI K

29 29 Super Fields (SUFI) Acknowledgement: Gives the SN up to which all PDUs are received correctly List: Lists the SNs of the PDUs which were not received correctly Bitmap: Indicates the erroneous PDUs in a bitmap Relative List: Optimised method of listing erroneous PDUs Move Receive Window: Moves the receiving window when SDU discard is performed No More Data: Indicates the end of a Status Report Window Size: This field is for flow control purposes

30 30 RLC Acknowledged Mode PDU (figure 5-10) Transmission buffer Retransmission buffer & management MUX Set fields in PDU Header (e.g. set poll bits) & piggybacked STATUS PDU RLC Control Unit Received acknowledgements Acknowledgements DCCH/ DTCH * AM-SAP DCCH/ DTCH ** DCCH/ DTCH ** AM RLC entity Demux/Routing DCCH/ DTCH * DCCH/ DTCH ** DCCH/ DTCH ** Reception buffer & Retransmission management Receiving side Segmentation/Concatenation Ciphering (only for AMD PDU) Add RLC header Reassembly Deciphering Remove RLC header & Extract Piggybacked information Piggybacked status Optional Transmitting side UE/UTRAN

31 31 MEDIUM ACCESS CONTROL (MAC) PROTOCOL ---INTRODUCTION---

32 32 The MAC layer offers services to upper layers in the form of : * data transfer on logical channels * reallocation of radio resources * MAC parameters : reconfiguration of MAC functions such as change of identity of UE, change of transport format (combination) sets, change of transport channel type. * reporting of measurements: such as traffic volume and quality indication

33 33 MEDIUM ACCESS CONTROL (MAC) PROTOCOL --- MAC FUNCTIONS ---

34 34 MAC Protocol Entity (1) MAC Services –Data Transfer –Reallocation of resources –Measurement reporting MAC Functions –Mapping between logical channels and transport channels –Selection of appropriate Transport Format for each Transport Channel depending on the instantaneous source rate –UE identification on common transport channels –Multiplexing of logical channels (common and dedicated) –Traffic volume measurement –Transport Channel Type switching –Ciphering for transparent mode RLC

35 35 MAC Functions –Mapping between logical channels and transport channels –Selection of appropriate Transport Format for each Transport Channel depending on the instantaneous source rate –Priority handling between data flows of one UE achieved by selecting “high bit rate” and “low bit rate” Transport Formats for different data flows. –UE identification on common transport channels the identification of the UE (Cell Radio Network Temporary Identity (C- RNTI) or UTRAN Radio Network Temporary Identity (U-RNTI)) is included in the MAC header. MAC Protocol Entity (2)

36 36 –Multiplexing of logical channels (common and dedicated) –Traffic volume measurement * Measure on the amount of data in the RLC transmission buffer * MAC compares the amount of data corresponding to a transport channel with the threshold set by RRC. If the amount of data is too high or too low, MAC sends a measurement report on traffic volume status to RRC. * use these reports for triggering reconfiguration of Radio Bearers and/or Transport Channels. –Transport Channel Type switching –Ciphering for transparent mode RLC MAC Protocol Entity (3)

37 37 MEDIUM ACCESS CONTROL (MAC) PROTOCOL --- ARCHITECTURE ---

38 38 Logical Channels Provided by L2/MAC sublayer to higher layers Defined by which type of information is transported Control Channels –Broadcast Control Channel (BCCH, DL) –Paging Control Channel (PCCH, DL) –Common Control Channel (CCCH, DL & UL) –Dedicated Control Channel (DCCH, DL & UL) Traffic Channels –Dedicated Traffic Channel (DTCH, DL & UL) –Common Traffic Channel (CTCH, DL)

39 39 Transport Channels Services provided by the physical layer (layer 1) to the MAC layer Defined by “how and with what characteristics” the data is transported Common Transport Channels –Broadcast Channel (BCH) (DL) –Paging Channel (PCH) (DL) –Random Access Channel (RACH) (UL) –Forward Access Channel (FACH) (DL) –Downlink Shared Channel (DSCH) (DL) –Common Packet Channel (CPCH) (UL) Dedicated Transport Channels –Dedicated Channel (DCH) (UL & DL) Same channel used by several users No UE identification provided by L1, in-band signaling of UE identity For exclusive use of one user UE inherently identified by the physical channel

40 40 MAC architecture (figure 5-11) FACHRACH DCCHDTCH DSCH MAC Control Iur or local MAC Control DCH MAC-d Serving RNC per UE USCH TDD only MAC-c/sh Controlling RNC, per cell CPCH FDD only CCCHCTCHBCCHSHCCH TDD only PCCH FACHPCHUSCH TDD only DSCH BCCH MAC Control MAC-b BCH Transparent RBS, per cell

41 41 MEDIUM ACCESS CONTROL (MAC) PROTOCOL --- MAC PDU AND FLOW ---

42 42 PDU in MAC The MAC PDU : consists of an optional MAC header and a MAC Service Data Unit (MAC SDU). Transport Block: Each RLC PDU (e.g. TMD, UMD or AMD) is mapped onto one and only one Transport Block. Transport Block Set(TBS): In the UE for the uplink, all MAC PDUs delivered to the physical layer within one Time Transmission Interval (TTI) are defined as Transport Block Set (TBS). It consists of one or several Transport Blocks, each containing one MAC PDU.

43 43 MAC DATA PDU (figure 5-12) MAC SDUC/TUE-Id MAC headerMAC SDU TCTF UE-Id type Ciphering Unit RLC PDU Target Channel Type Field (TCTF) identifies the type of logical channel (CCCH, BCCH, CTCH, DTCH/DCCH) on RACH/FACH. UE-Id provides an identifier of the UE on common transport channels. UE-Id type is needed to ensure correct coding of the UE-Id field. C/T identifies the logical channel number (in case of MAC multiplexing of several DTCH and DCCH).

44 44 Target Channel Type Field (TCTF) (table 5-1 and 5-2) TCTFDesignation 00BCCH CCCH Reserved (PDUs with this coding will be discarded by this version of the protocol) CTCH Reserved (PDUs with this coding will be discarded by this version of the protocol) 11DCCH or DTCH over FACH TCTFDesignation 00CCCH 01DCCH or DTCH over RACH 10-11Reserved (PDUs with this coding will be discarded by this version of the protocol) Provides identification of the logical channel class on FACH or RACH

45 45 C/T Field (table 5-3) C/T field Designation 0000Logical channel Logical channel Logical channel Reserved (PDUs with this coding will be discarded by this version of the protocol) Provides identification of the logical channel instance when multiple channels are carried on the same transport channel.

46 46 UE Id Field (table 5-4) UE Id typeLength of UE Id field U-RNTI32 bits C-RNTI16 bits Provides an identifier of the UE on common transport channels.

47 47 UE-Id Type Field (table 5-5) UE-Id Type field 2 bits UE-Id Type 00U-RNTI 01C-RNTI 10 Reserved (PDUs with this coding will be discarded by this version of the protocol) 11 Reserved (PDUs with this coding will be discarded by this version of the protocol) Needed to ensure correct coding of the UE-Id field

48 48 WCDMA RAN side MAC architecture / MAC-d details (1) DCCH UE DTCH DCH MAC-d to MAC-c/sh MAC-Control C/T MUX DL scheduling/ priority handling Ciphering Transport Channel Type Switching Flow Control MAC–c/sh / MAC-d C/T MUX / Priority setting Deciphering

49 49 WCDMA RAN side MAC architecture / MAC-d details (2) Transport Channel Type Switching : If requested by RRC, MAC switches the mapping of one designated logical channel between common and dedicated transport channels. C/T MUX : a C/T field is added indicating the logical channel instance where the data originates. This is always needed for common transport channels, such as the FACH, but for dedicated it is only needed when several logical channels are multiplexed into C/T MUX. Priority setting function : is responsible for priority setting on data received from DCCH/DTCH. flow control function flow control function : exists between MAC-c/sh and MAC-d to limit buffering in the MAC-c/sh entity. Ciphering/deciphering : in MAC-d is only performed for transparent mode data.

50 50 WCDMA RAN side MAC architecture / MAC-c/sh details (1) CTCH FACH MAC-c/sh to MAC–d RACH MAC– Control CPCH (FDD only ) CCCH FACH BCCH SHCCH (TDD only) PCCH PCH TFC selection DSCH USCH TDD only Flow Control MAC-c/sh / MAC-d TCTF MUX / UE Id MUX USCH TDD only DSCH DL: code allocation Scheduling / Priority Handling/ Demux TFC selection

51 51 WCDMA RAN side MAC architecture / MAC-c/sh details (2) UE id MUX: After receiving the data from MAC-d, the MAC-c/sh entity first adds the UE identification type, which is the actual UE identification (CRNTI or U-RNTI). the scheduling/priority handling function the scheduling/priority handling function : is to decide the exact timing when the PDU is passed to layer 1 via the FACH transport channel with an indication of what transport format used. The Transport Format Combination (TFC) selection : is done in the downlink for FACH, PCH and DSCH. DL code allocation : is only used to indicate the code if DSCH is used.

52 52 CTCH FACH MAC-c/sh RACH MAC-Control CCCH FACH BCCHPCCH PCH TFC selection Flow Control MAC-c/sh/MAC-d TCTF MUX / UE Id MUX Scheduling / Priority Handling/ Demux DCCHDTCH DCH MAC-d DL scheduling/ priority handling Ciphering Transport Channel Type Switching C/T MUX Priority setting Deciphering C/T MUX MAC Model/WCDMA RAN side (figure 5-13 and figure 5-14 connected)

53 53 MEDIUM ACCESS CONTROL (MAC) PROTOCOL --- TRANSPORT FORMAT ---

54 54 The Transport Format (TF) and Transport Format Set (TFS) : describes the data transfer format offered by L1 to MAC (and vice versa) and is configured by RRC for a specific transport channel. Each transport channel is configured with one or more Transport Formats (TF). This is referred to as the Transport Format Set (TFS) * The maximum number of TFs per transport channel is 32 (numbered 0-31). * Each TF corresponds to a certain number of equal size transport blocks, i.e. Transport Block Set (TBS), which may be transmitted on the transport channel within the same interval. * The length of the interval is defined by the Transmission Time Interval (TTI), which is a fixed periodicity of transport blocks and can have a length of 10, 20, 40 and 80 ms.

55 55 Transport Format Set (TFS) (figure 5-15) TF1 TF2 TF3 Only the dynamic attributes differ between the TFs within the TFS Increasing bit rate TFS

56 56 Transport format (figure 5-16) Describes instantaneous characteristics of a transport channel and the data transfer format offered by L1. Semi-static part –Transmission Time Interval (TTI) –Channel-coding scheme –Reconfiguration by RRC is needed. Dynamic part –Number of transport blocks per TTI –Number of bits per transport block TTI Transport Block L bits N

57 57 Transport Channel Coding (figure 5-17) Add CRC Channel coding Interleaving Transport Channel Coded Transport Channel CRC (Cyclic Redundancy Check) – Calculated for and added to each transport block – CRC length : 0/8/12/16/24 bits FEC (Forward Error Correction) – Convolution coding (R=1/2, R=1/3) – Turbo coding (R=1/3) Channel Interleaving – Block interleaving over one TTI

58 58 TTI (typically 20 ms) Rate = RRate = R/4Rate = R/2 Examples of transport channel structures, simple variable rate speech and packet data (figure 5-18) Simple variable-rate speech TTI = 20 ms Convolutional coding One transport block per TTI (one speech frame) Variable-length transport blocks TTI One ”packet” Packet data Turbo coding Fixed-length transport blocks Variable number of transport block per TTI

59 59 Characterization of Transport Format

60 60 A connection typically consists of multiple transport channels in each direction One set of transport formats per transport channel Transport Format Combination (TFC): –The instantaneous combination of transport formats for all transport channels to (from) one UE –Signaled over L1 as Transport Format Combination Indicator (TFCI) UTRAN UE DL TrCh #1DL TrCh #MUL TrCh #1UL TrCh #N Multiple transport channels (figure 5-19)

61 61 Transport Format Set (TFC) (figure 5-20) A combination of currently valid Transport Formats at a given point of time containing one Transport Format for each transport channel. TF1 TF2 TF3 TF1 TF2 TF3 TF1 TF2 TF3 Transport channel 1 Transport channel 2 Transport channel 3 TFC1

62 62 Transport Format Set (TFCS) (figure 5-21) TF1 TF2 TF3 TF1 TF2 TF3 TF1 TF2 TF3 Transport channel 1 Transport channel 2 Transport channel 3 TFC1 TFC2 TFC3 TFC4 TFCS TFCS is the set of TFCs that has been configured (by RRC) MAC selects a TFC out of the TFCS Current TFC is indicated by the Transport Format Combination Indicator (TFCI) in each physical frame every 10 ms

63 63 Summary of Data Exchange through transport channels Transport block: the basic unit exchanged between L1 and MAC Transport block set: a set of transport blocks which are exchanged between L1 and MAC at the same time instance on the same TrCH The Transmission Time Interval (TTI) and the error protection scheme to apply are semi- static parameters for the TrCH while the number of transport blocks and their size are dynamic ones Transport format: a defined format offered by L1 for the delivery of a Transport Block Set during a TTI Transport format set: a set of Transport Formats associated to a Transport Channel Transport Format Combination: a combination of transport formats submitted simultaneously to L1, containing one Transport Format for each transport channel. Transport Format Combination Set: a set of transport format combinations The Transport Format Combination Indicator (TFCI): on L1 indicates the currently valid TFC.

64 64 MEDIUM ACCESS CONTROL (MAC) PROTOCOL --- CHANNEL SWITCHING ---

65 65 The purpose of Channel Switching : is to optimize the use of the radio resources, by dynamically changing the resources allocated to the best-effort users. When there are plenty of resources available, the best-effort user receives high bit rates but when the system is heavily loaded and there are not many resources left,

66 66 Channel Switching 1. CELL_FACH to CELL_DCH: Bufferbased 2. CELL_DCH to CELL_FACH: Throughput 3. Upswitch: Bandwidth 4. Downswitch: DL Code Power Based 5. Downswitch: Handover Based 6. Downswitch: CELL_FACH to Idle due to inactivity 7. Multi-RAB Upswitch: Bufferbased 8. Multi-RAB Downswitch: Throughput based Copyright © Ericsson Education. All rights reserved Cell_DCH 64/384 Cell_DCH 64/64 Cell_FACH Cell_DCH 64/128 Idle Mode 6. No activity 1. Common to Dedicated based on buffer size Soft Congestion 5. SHO can initiate a switch if it fails to add a RL 4. Coverage triggered downswitch 3. Upswitch based on bandwidth 2. Dedicated to common based on throughput Cell_DCH Speech + PS 64/64 Cell_DCH Speech + PS 0/0 7. UL or DL buffer size above a threshold 8. UL & DL throughput = 0 for a certain time

67 67 1. Switch from Cell_FACH to Cell_DCH state based on the buffer load. Downlink buffer load measurements in the S-RNC, uplink buffer load measurement by the UE in the MAC layer. in the Idle State or Cell_FACH the UE will read the System Information and configure its measurements. For the DCH state, measurements are configured by a “Measurement Control” message. In the UL case the UE sends a “Measurement Report” to the RNC when the buffer size is reached. In the DL case, the RNC handles the switch internally.

68 68 2. switch from Cell_DCH to Cell_FACH Throughput based triggers the MAC layer to report to RRC and send a “Measurement Report” to the RNC for low throughput in UE. If both the throughput in the UL and the DL is below the set values, a switch from Cell_DCH to Cell_FACH will be performed via Radio Bearer Reconfiguration procedure. 3. Up Switch between the Radio Bearers for the Cell_DCH state based on bandwidth need. The supported bit rates are 64/64, 64/128 and 64/384 kbps. When the throughput becomes close to the maximum user bandwidth (64 or 128 kbps) the procedure is triggered. In the UL case, the UE sends a “Measurement Report” and in the DL case it is handled in the RNC internally.

69 69 4. Down Switch between the Radio Bearers for the Cell_DCH state performed due to coverage, i.e. due to DL power. In this case the congestion control triggers it based on measurements via NBAP (from RBS to RNC). 5. Other channel switching type is not indicated here !!!!

70 70 Channel switching (UL) (figure 5-22)

71 71 MAC SDUC/T MAC header MAC SDU Ciphering Unit RLC PDU No MAC header is needed for the DTCH. Multiplexing of logical channels (DCCHs used for SRBs, C/T MUX) Mapped on DCH transport channels Channel Switching from dedicated to common (DCCH and DTCH) before switching (figure 5-24) Channel switching MAC-d DTCH TFC Selection DCH Physical layer L1 Ciphering C/T MUX DCCHs MAC SDU Ciphering Unit RLC PDU DCCHsDTCH

72 72 Channel Switching from dedicated to common (DCCH and DTCH) after switching (figure 5-25) MAC SDUC/TUE-Id MAC headerMAC SDU TCTF UE-Id type Ciphering Unit RLC PDU Switching is transparent for the logical channels DTCH and DCCH mapped to RACH/FACH MAC header fields to distinguish logical channels and UEs DCCH DTCH Channel switching C/T MUX UE ID TCTF MUX CCCH CTCH BCCH RACHFACH MAC-d MAC-c Physical layer, L1

73 73 CIPHERING

74 74 The protection of the user data and some of the signaling information is done by both integrity protection, executed by RRC layer and ciphering, performed either in RLC or in the MAC layer according to the following rules: * If a radio bearer is using a non-transparent RLC mode (AM or UM), ciphering is performed in the RLC sub layer. * If a radio bearer is using the transparent RLC mode, ciphering is performed in the MAC sub layer (MAC-d entity). >> If ciphering is used it is between S-RNC and UE <<

75 75 SRNC f8CK COUNT-C BEARER DIRECTION LENGTH f8CK COUNT-C BEARER DIRECTION LENGTH PLAIN TEXT BLOCK CIPHERTEXT BLOCK PLAIN TEXT BLOCK SRNC // Sender UE or SRNC Receiver SRNC or UE Ciphering of user and signaling data transmitted over the radio access link (figure 5-26) (1) KEYSTREAM

76 76 Procedure for ciphering: * The input parameters to the algorithm : the ciphering key, CK, a time-dependent input, COUNT-C, the bearer identity, BEARER, the direction of transmission, DIRECTION, and the length of the key stream required, LENGTH. * Based on these input parameters the algorithm generates the output keystream block, KEYSTREAM, that is used to encrypt the input plaintext block, PLAINTEXT, to produce the output ciphertext block, CIPHERTEXT. Ciphering of user and signaling data transmitted over the radio access link (figure 5-26) (2)

77 77 Input Parameters to the Cipher Algorithm (1) COUNT-C : ciphering sequence number CK, Ciphering Key: The CK is established during the Authentication procedure using cipher key derivation function f3 available in the USIM and in the HLR/AUC BEARER : There is one BEARER parameter per radio bearer associated with the same user. The radiobearer identifier is input to avoid that for different keystream an identical set of input parameter value is used. DIRECTION : The value of the DIRECTION is 0 for UL messages and 1 for DL.

78 78 Input Parameters to the Cipher Algorithm(2) LENGTH : The parameter determines the length of the required keystream block. Ciphering key selection: There is one CK for CS radio bearer, CKCS, connections and one CK for PS radio bearer, CKPS, connections.

79 79 PHYSICAL CHANNELS

80 80 Physical channels The final Layer 1 bit stream to be carried over the air –Multiple multiplexed coded transport channels (CCTrCH) –Layer 1 control information Pilot bits Transmit Power Control (TPC) commands and other Feedback Information (FBI) Transport Format Combination Indicator (TFCI) Mapped to combination of –Carrier frequency –Code (channelization/scrambling code pair) –Relative phase (UL only): On either the I branch or the Q branch of a QPSK signal (uplink only).

81 81 Physical-layer overview (figure 5-27) Channel coding Transport channels Multiplexing Mapping to physical channels Spreading Physical channels Physical-layer procedures and measurements Channel coding  5 MHz Modulation 3.84 Mcps Transport-channel processing

82 82 RRC Connection Establishment (figure 5-28) WCDMA RAN ”RRC Connection Request” CCCH/RACH ”RRC Connection Setup” CCCH/FACH ”RRC Connection Setup Complete” DCCH/DCH Idle Mode WCDMA RAN Connected Mode

83 83 Physical Random Access Channel (figure 5-29) I Q Random Access Message (10, 20, 40, or 80 bits per slot) RACH Message Control Slot (0.666 mSec) Pilot (8 bits) RACH Message Data Slot (0.666 mSec) TFCI (2 bits) 1 Frame = 15 slots = 10 mSec

84 84 RACH carrying RRC Connection request (figure 5-30) 384 Rate 1/2 CC 300 Rate Matching 1 st Interleaving Transparent Mode => no RLC header 20 RACH Message part 30ksps SF 128 PILOTTFCI 166 CRC bit MAC header 168 MAC layer 8 tail bits Kbps => 166 bits in 20msec 2 nd Interleaving 20 Slot segmentation I branch Q 82 Control part

85 85 Secondary Common Control Physical Channel (figure 5-31) Carries the Forward Access Channel (FACH) and Paging Channel (PCH) Spreading Factor = 256 to 4 1 Slot = mSec = 2560 chips = 20 * 2 k data bits; k = [0..6] 1 Frame = 15 slots = 10 mSec 20 to 1256 bits0, 2, or 8 bits DataTFCI or DTXPilot 0, 8, or 16 bits

86 86 FACH carrying RRC Connection setup (figure 5-32) st Interleaving 160 CRC Rate 1/2 CC Unacknowledged Mode (UM) => 8 bit RLC 8 bit MAC nd Interleaving MAC layer tail bits 152 Max rate 3040 bps => 10msec = 304 bits = 2X152 S-CCPCH 60ksps => SF = L1 (8 bit TFCI) 72 Slot segmentation Rate Matching

87 87 Uplink DPDCH/DPCCH (figure 5-33) Coded Data, 10 x 2 k bits, k=0…6 (10 to 640 bits) Dedicated Physical Data Channel (DPDCH) Slot (0.666 mSec) PilotFBITPC Dedicated Physical Control Channel (DPCCH) Slot (0.666 mSec) 1 Frame = 15 slots = 10 mSec I Q TFC I DPCCH: 15 kb/sec data rate, 10 total bits per DPCCH slot PILOT: Fixed patterns (3, 4, 5, 6, 7, or 8 bits per DPCCH slot) TFCI: Transmit Format Combination Indicator (0, 2, 3, or 4 bits) FBI: Feedback Information (0, 1, or 2 bits) TPC: Transmit Power Control bits (1 or 2 bits); power adjustment in steps of 1, 2, or 3 dB

88 88 Uplink Signaling Radio Bearer on DPDCH/DPCCH (figure 5-34) PILOTTFCITPC DPDCH 60ksps => SF = 64 I branch Q 622 DPCCH 15ksps 600 Rate Matching 40 2 nd Interleaving Slot segmentation Rate 1/3 CC 1 st Interleaving CRC tail bits MAC Layer 4 bit MAC bit RLC 144 RRC UM RRC AM or NAS DT normal or high priority bit RLC 4 bit MAC 136 bits in 10 msec => 13.6 kbps 128bits in 10 msec => 12.8 kbps

89 89 Downlink DPDCH/DPCCH (figure 5-35) 1 Slot = mSec = 2560 chips = 10 x 2 k bits, k = [0...7] SF = 512/2 k = [512, 256, 128, 64, 32, 16, 8, 4] The DPDCH carries user traffic, layer 2 overhead bits, and layer 3 signaling data. The DPCCH carries layer 1 control bits: Pilot, TPC, and TFCI Downlink Closed-Loop Power Control steps of 1 dB dB The DPDCH carries user traffic, layer 2 overhead bits, and layer 3 signaling data. The DPCCH carries layer 1 control bits: Pilot, TPC, and TFCI Downlink Closed-Loop Power Control steps of 1 dB dB Data 2TFCIData 1TPC 1 Frame = 15 slots = 10 mSec DPDCH Pilot DPDCH DPCCH

90 90 Downlink Signaling Radio Bearer on DPDCH/DPCCH (figure 5-36) Rate 1/3 CC 1 st Interleaving CRC tail bits MAC Layer 4 bit MAC bit RLC bit RLC 4 bit MAC 510 Rate Matching 2 nd Interleaving DPDCH/DPCCH = 30ksps => SF = TPC & 4 PILOT 136 bits in 10 msec => 13.6 kbps 128bits in 10 msec => 12.8 kbps RRC UM RRC AM or NAS DT normal or high priority 34 Slot segmentation

91 91 Uplink Speech RAB mapping (figure 5-37) 1 st Interleaving I Branch Q nd speech block bits (600 symbols) # # tail bits CRC Rate 1/3 CC 1st interleaving MAC Layer 4 bit MAC bit RLC bit RLC 4 bit MAC 40 msec Convolutional coding 8 tail bits Radio frame equalization CRC /3 1/ msec of each subflow DPDCH 60kbps => SF=64 2 nd interleaving Rate match 360 Q PILOTTFCITPC622 DPCCH 15kbps DPDCH 60kbps => SF=64 2 nd interleaving Rate match 360 Frame segmentation RRC UM RRC AM or NAS DT normal priority Rate matching

92 92 Uplink Speech RAB mapping (during SID frame) (figure 5-38) After every eight frames the UE sends a Silence Descriptor (SID) frame, which is used during the discontinuous speech periods.

93 93 Downlink Speech RAB mapping (figure 5-39) nd speech block #2 110# tail bits CRC Rate 1/3 CC 1st interleaving MAC Layer 4 bit MAC 136 RRC UM 8 bit RLC RRC AM or NAS DT normal priority bit RLC 4 bit MAC 40 msec Frame segmentation nd interleaving nd interleaving st interleaving 144 DPDCH 60ksps => SF=128DPDCH 60kbps => SF=128 2 TPC 4 Pilot Convolutional coding 8 tail bits CRC (1/3)333 (1/3)136 (1/2) Rate matching 20 msec of each subflow

94 94 Uplink CS 64 RAB mapping (figure 5-40) I Branch Q nd speech block bits (600 symbols) # tail bits CRC Rate 1/3 CC 1st interleaving MAC Layer 4 bit MAC bit RLC RRC UM RRC AM or NAS DT normal priority bit RLC 4 bit MAC 40 msec Frame segmentation 136 DPDCH 240kbps => SF=16 2 nd interleaving Q PILOTTFCITPC622 DPCCH 15kbps DPDCH 240kbps => SF=16 2 nd interleaving Rate matching 12 Trellis termination bits 1st Interleaving Turbo Coding kbps = 1280 in 20 msec =>2X640 bit Transport Blocks 144 CRC #2 110

95 95 Downlink CS 64 RAB mapping (figure 5-41) nd speech block tail bits CRC Rate 1/3 CC 1st interleaving MAC Layer 4 bit MAC bit RLC bit RLC 4 bit MAC 40 msec Frame segmentation nd interleaving nd interleaving st interleaving 144 DPDCH 120ksps => SF= Rate matching 12 Trellis termination bits Turbo Coding CRC / 8 / 8 TPC/TFCI/PILOT kbps = 1280 in 20 msec =>2X640 bit Transport Blocks RRC UM RRC AM or NAS DT normal priority

96 96 Uplink Streaming 57.6 kbps RAB mapping (figure 5-42) I Branch Q nd speech block bits (600 symbols) # # tail bits CRC Rate 1/3 CC 1st interleaving MAC Layer 4 bit MAC bit RLC bit RLC 4 bit MAC 40 msec Frame segmentation 136 DPDCH 240kbps => SF=16 2 nd interleaving Q PILOTTFCITPC622 DPCCH 15kbps DPDCH 240kbps => SF=16 2 nd interleaving Rate matching 12 Trellis termination bits 1st Interleaving 7116 Turbo Coding Up to 4X576 TBs in 40 msec => max data rate = 57.6 kbps CRC 16 RRC UM RRC AM or NAS DT normal priority

97 97 Downlink Streaming 57.6 kbps RAB mapping (figure 5-43) nd speech block tail bits CRC Rate 1/3 CC 1st interleaving MAC Layer 4 bit MAC bit RLC bit RLC 4 bit MAC 40 msec Frame segmentation nd interleaving nd interleaving st interleaving 144 DPDCH 120ksps => SF=32DPDCH 120kbss => SF= Rate matching 12 Trellis termination bits Turbo Coding Up to 4X576 TBs in 40 msec => max data rate = 57.6 kbps CRC / 8 / 8 TPC/TFCI/PILOT RRC UM RRC AM or NAS DT normal priority 1941

98 98 Uplink PS DATA CELL_FACH (DCCH on RACH) (figure 5-44) RRC AM, NAS DT normal or low priority 16 CRC MAC layer 8 tail bits Rate 1/2 Convolutional Coding st Interleaving 24 bit MAC 136 RRC UM bit RLC bit RLC 24 bit MAC 2 nd Interleaving Rate Matching RACH message part 30ksps => SF = 128 PILOTTFCI Slot segmentation I Branch Q 136 bits in 10 msec => 13.6 kbps 128 bits in 10 msec => 12.8 kbps

99 99 Uplink PS DATA CELL_FACH (DTCH on RACH) (figure 5-45) Frame segmentation nd Interleaving Rate Matching RACH message 30ksps => SF = 128 PILOTTFCI CRC MAC layer 8 tail bits Rate 1/2 Convolutional Coding st Interleaving AM => 16 bit RLC bit MAC 320 Max user plane 320 bits in 20 msec => 16 kbps 82 Frame segmentation nd Interleaving Rate Matching RACH message 30ksps => SF = 128 PILOTTFCI 20 82

100 100 Downlink PS DATA CELL_FACH (DCCH on FACH) (figure 5-46) st Interleaving CRC Rate 1/2 Convolutional Coding 752 Rate Matching nd Interleaving S-CCPCH = 60ksps => SF = tail bits MAC layer 24 bit MAC 136 RRC UM 8 bit RLC RRC AM or NAS DT normal priority bit RLC 24 bit MAC 40 msec Slot segmentation 136 bits in 10 msec => 13.6 kbps 128 bits in 10 msec => 12.8 kbps TFCI bits

101 101 Downlink PS DATA CELL_FACH (DTCH on FACH) (figure 5-47) Rate Matching nd Interleaving S-CCPCH = 60ksps => SF = Slot segmentation st interleaving CRC Turbo Coding trellis termination bits AM => 16 bit RLC header 24 bit MAC header Max user plane = 320 bits in 10msec => 32 kbps TFCI bits

102 102 Uplink PS 64 RAB mapping (figure 5-48) I Branch Q nd speech block bits (600 symbols) # # tail bits CRC Rate 1/3 CC 1st interleaving MAC Layer 4 bit MAC bit RLC bit RLC 4 bit MAC 40 msec Frame segmentation 136 DPDCH 240kbps => SF=16 2 nd interleaving Q PILOTTFCITPC622 DPCCH 15kbps DPDCH 240kbps => SF=16 2 nd interleaving Rate matching 12 Trellis termination bits Up to 4X320 TBs in 20 msec => max data rate = 64 kbps 144 1st Interleaving 4236 Turbo Coding bit RLC CRC 16 RRC UM RRC AM or NAS DT normal priority

103 103 Downlink PS 64 RAB mapping (figure 5-49) nd speech block tail bits CRC Rate 1/3 CC 1st interleaving MAC Layer 4 bit MAC bit RLC bit RLC 4 bit MAC 40 msec nd interleaving nd interleaving DPDCH 120ksps => SF=32DPDCH 120kbss => SF= Frame segmentation 1st interleaving 1966 Rate matching 12 Trellis termination bits Turbo Coding Up to 4X320 TBs in 20 msec => max data rate = 64 kbps bit RLC CRC / 8 / 8 TPC/TFCI/PILOT RRC UM RRC AM or NAS DT normal priority

104 104 Downlink PS 128 RAB mapping (figure 5-50) nd speech block tail bits CRC Rate 1/3 CC 1st interleaving MAC Layer 4 bit MAC bit RLC bit RLC 4 bit MAC 40 msec Frame segmentation nd interleaving nd interleaving st interleaving 144 DPDCH 240ksps => SF= Rate matching 12 Trellis termination bits Turbo Coding Up to 8X320 TBs in 20 msec => max data rate = 128 kbps 16 bit RLC CRC / 8 / 16 TPC/TFCI/PILOT RRC UM RRC AM or NAS DT normal priority

105 105 Downlink PS 384 RAB mapping (figure 5-51) 95 Next 3 blocks tail bits CRC Rate 1/3 CC 1st interleaving MAC Layer 4 bit MAC bit RLC bit RLC 4 bit MAC 40 msec Trellis termination bits nd interleaving DPDCH 480ksps => SF= Turbo Coding Up to 12X320 TBs in 10 msec => max data rate = 384 kbps Rate matching 1st interleaving 8 TCI 8 TPC 18 Pilot 600 RRC UM RRC AM or NAS DT normal priority

106 106 I Branch Q tail bits CRC Rate 1/3 CC 1st interleaving 4 bit MAC bit RLC bit RLC 4 bit MAC 40 msec 8 tail bits CRC /3 1/ msec of each subflow DPDCH 60kbps => SF=16 2 nd interleaving PILOTTFCITPC622 DPCCH 15kbps DPDCH 60kbps => SF=16 2 nd interleaving RRC UM RRC AM or NAS DT normal priority Uplink MultiRAB, Speech RAB + PS 64/64 RAB mapping (figure 5-52) 1st Interleaving 4236 Turbo Coding bit RLC CRC

107 tail bits CRC Rate 1/3 CC 1st interleaving 4 bit MAC 136 RRC UM 8 bit RLC RRC AM or NAS DT normal priority bit RLC 4 bit MAC 40 msec nd interleaving DPDCH 120 ksps => SF=32 4 TPC 8 Pilot 8 TFCI CC 8 tail bits CRC (1/3)333 (1/3)136 (1/2) msec of each subflow 160 RM 276 RM 258 RM st Int st Int. 2761st Int Downlink MultiRAB, Speech RAB + PS 64/64 RAB mapping (figure 5-53) Trellis termination bits Turbo Coding 4224 RM st Int Up to 4X320 TBs in 20 msec => max data rate = 64 kbps bit RLC CRC


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