Wideband tdd wcdma for the unpaired spectrum phần 4 pot

As the name indicates,Physical Uplink and Downlink Shared Channels are common channels on which severalusers may send and receive data.sub-Higher layer signaling is used to indicate to t

Layer 1 Structure 53

Parameter

Associated Codes Scrambling

Code

Long Basic Midamble Code

Short Basic Midamble Code

UEs will use the PRACH/P for UL communication with UTRAN when they do not have

a dedicated channelization code assigned, such as during initial access to UTRAN Thisresults in the possibility of collision (i.e multiple UEs using the same PRACH/P at thesame time) For this reason, a set of admissible channelization codes on the PRACH/P isspecified, from which the UE randomly selects a code The random selection is used tominimize the possibility of collision The midamble is determined through a fixed associ-ation between the midamble and the channelization code [7] The available midambles forPRACH/P are from the long midamble set, using either all eight shifts or only the four oddshifts from k= 1 to 8 Using odd-only shifts is intended for larger cells; whereby usingonly half of the available midamble shifts allows for double-length channel responses.For larger cells, the effective number of available midamble shifts can be doubled fromfour to eight by using a second basic midamble sequence, which is a time ‘inverted’ orreverse version of the original basic midamble sequence

Since Random Access is used for initial access to UTRAN, the UE does not have tighttime synchronization with the UTRAN For this reason, PRACH/P uses Type-3 bursts,which have the larger guard period of 192 chips This reduces the probability of thePRACH/P transmission spilling into an adjacent timeslot Power Control is not used onthe PRACH/P channel

Each PRACH/P can be split into N-subchannels, with the i-th subchannel using theframes with i= SFN mod N, with possible values of N being 1, 2, 4 or 8 The purpose

of the subchannels is to reduce probability of collision, by offering more opportunitiesfor random transmissions

Multiple PRACH/Ps may be configured on the same or different timeslots If theyare on different timeslots, then each PRACH/P may use the channelization codes andsubchannels without any restrictions However, if they are on the same timeslot, theneach PRACH/P must use distinct subsets of channelization codes and sub-channels From

a service point of view, the Random Access Channel is partitioned into a number of AccessService Classes (ASCs), each having a relative priority level For example, high priorityASCs are assigned for Emergency Calls as well as for Network Operator personnel, etc.Each ASC is mapped onto one or more PRACH/P subchannels and a set of associatedchannelization codes

The details of the PRACH/PC (Timeslot, channelization code list, midamble type, channels, ASCs, etc.) are transmitted by the UTRAN on the broadcast channel PhysicalUplink and Downlink Shared Channels: PUSCH/P and PDSCH/P As the name indicates,Physical Uplink and Downlink Shared Channels are common channels on which severalusers may send and receive data.

sub-Higher layer signaling is used to indicate to the UE that there is data to decode onthe shared channels PDSCH/P and PUSCH/P use the same burst structure of PDCH/P asdescribed in Section 4.3.1.2

4.3.1.7 Physical Paging Indicator Channel: PICH/P

The Physical Paging Indicator Channel (PICH/P) is a physical channel used to carry thepaging indicators The PICH/P is always transmitted at a power level that is broadcast insystem information (specified as an offset from the PCCPCH/P reference power level)

A Paging Indicator is a sequence of LPIsymbols, which indicates to a UE whether ornot Paging Information is present in the following occurrence of the Paging (transport)channel (PCH/T) LPI is either 2, 4 or 8 symbols A single Paging Indicator is assigned

to a group of the UEs based on IMSIs (International Mobile Subscriber Identity) Thisincreases the system’s paging capacity but will sometimes cause UEs to decode the PCH/Twhen they have not been paged

Bursts of Type-1 or Type-2 are used to carry Paging Indicators With a spreading factor

of 16 and with 4 bits being reserved, the number of bits available for Paging Indicators(NPIB) is 240 for Type-1 and 272 for Type-2 bursts, see Figure 4.8

Accordingly, the number of Paging Indicators per Burst, NPI, is easily determined to

be as shown in Table 4.4

A number of PICH Bursts (NPICH), with one burst per timeslot per frame, form a PICHBlock, as shown in Figure 4.9

Thus, the total number of Paging Indicators per PICH Block NP is NPICH∗NPI

Bits for Paging Indication Reserved Bits Bits for Paging Indication

b0 b1 bNPIB/2−1bNPIB bNPIB+1 bNPIB+2bNPIB+3bNPIB/2bNPIB/2+1 bNPIB−1

Period

1 Timeslot

Figure 4.8 Paging Indicators in a PICH Burst

Table 4.4 Number of Paging Indicators per Burst

Burst Type 1 NPI = 60 NPI = 30 NPI = 15 Burst Type 2 NPI = 68 NPI = 34 NPI = 17

Layer 1 Structure 55

1 PICH Block

P0, ,PNPI−1 P0, , PNPI−1 P0, , PNPI−1 P0, , PNPI−1

Figure 4.9 Structure of a PICH/P Block

PICH data does not use the channel coding, rate matching or interleaving used by othertransport channel types PICH data is in effect repetition-coded (LPItimes) and interleavedbetween the first and second data fields

4.3.2 Transport Channels

As explained in Section 4.1, Transport Channels are the services that the Physical Layer

provides to Layer 2 Transport Channels are characterized by how data is transferred, in

terms of the size of the data block, the periodicity of the data blocks, the type of errorprotection, etc A Transport Channel is a very flexible concept that allows a variety ofchannels with very different characteristics to be realized

The definition of a Transport Channel is based on the concepts of Transmission TimeInterval and Transport Format as follows Briefly, a Transport Channel consists of asequence of time periods, called Transmission Time Intervals (TTIs) Data in a TTIconsists of one or more ‘Transport Blocks’, carrying equal number of bits The data

is characterized by a ‘Transport Format (TF)’, which specifies the number of TransportBlocks, the number of data bits per Transport Block and the duration of the TTI itself.The Transport Format also specifies other parameters, as described below

The TTI can be either 10, 20, 40 or 80 msecs The number of TBs in a TTI can

be 0 through 512, with 0 TBs denoting that no data is transported within that TTI.The maximum number of bits in a TB is 5000 Additional so-called semi-static TBattributes are:

1 Coding Scheme (Convolutional Rate 1/2 or Convolutional Rate 1/3 or Turbo orNo-coding)

2 Number of CRC bits (0, 8, 12, 16, 24)

3 Rate Matching parameter (integer from 1 to 256) The Rate Matching parameter putslimits on the number of error-coded bits that may be punctured (or deleted) in theprocess of mapping the data from multiple transport channels onto a CCTrCH Ifthe RM parameter is higher for one TrCH than for another, the one with the higher

RM parameter would be given more of the output bits and, therefore less puncturingwould be performed on that TrCH If there is only one TrCH in the CCTrCH, the RMparameter has no effect

TB size (bits), number of TBs and TTI, which effectively determine the Layer 2 to Layer

1 data rate, can be ‘changed’ on a TTI basis That is, the following so-called ‘dynamic’

attributes can have multiple values, one of which is selected or in effect for any particularTTI: (1) transport block size; (2) number of transport blocks per TTI; and (3) TTI Theseparameters are changed by the MAC, which performs TFC selection, based on a number

of factors such as data available from each logical channel and logical channel priority.The other TrCH parameters are referred to as semi-static parameters TTI can be either

a dynamic or a semi-static parameter These parameters require higher layer signaling Allthe attributes characterizing a TrCH can be changed on a slow basis by reconfiguration.The set of possible TFs for a Transport Channel is called a Transport Format Set (TFS)and each TF within the TFS is known by a unique Transport Format Indicator (TFI)

TF1: Dynamic part:{TB size = 320 bits, No of TBs = 1};

Semi-static part:{TTI = 10 ms, Coding = Convolutional,Coding Rate= 1/2; Static rate matching parameter = 2}.

TF2: Dynamic part:{TB size = 320 bits, No of TBs = 2};

Semi-static part: {TTI = 10 ms, Coding = Convolutional, Coding Rate = 1/2;

Static rate matching parameter= 2}

TF3: Dynamic part:{TB size = 480 bits, No of TBs = 3};

Semi-static part: {TTI = 10 ms, Coding = Convolutional, Coding Rate = 1/2;

Static rate matching parameter= 2}

Specific Realization in time: (TF1, TF3, TF2) is shown in Figure 4.10

Coded Composite Transport Channel (CCTrCH): Multiple Transport Channels withdifferent error protection requirements (which are driven by the Quality of Service require-ments) can be multiplexed to form a Coded Composite Transport Channel (CCTrCH).This can save physical resources by sharing them among multiple transport channels Theparameters of the individual TrCHs (number of bits after error coding+ rate matching)must be such that their mapping onto the allocated Physical Channels is possible.The structure of the Coded Composite Transport Channels is based on the concept ofTransport Format Combination (TFC), which is introduced via an example For example,consider 3 Transport Channels (TrCH1, TrCH2 and TrCh3) being combined to form asingle CCTrCH Let the associated Transport Format Sets be TFS1= {TF1, TF2}, TFS2 =

{TF1} and TFS3 = {TF1, TF2, TF3}, where TF1, TF2 and TF3 are as defined in theprevious example A ‘Transport Format Combination’ refers to allowed combinations

of Transport Formats for the three channels For example, TFC1= {TrCH1 =

TrCH

Transmission Time Interval Transport Block

Transport Block Transport Block Transport Block

Transport Block Transport Block

Layer 1 Structure 57

TF1, TrCH2= TF1, TrCH3 = TF1}, TFC2 = {TrCH1 = TF2, TrCH2 = TF1, TrCH3 =TF2} and TFC3 = {TrCH1 = TF1, TrCH2 = TF1, TrCH3 = TF3} Note that the number

of allowed TFCs (3) is smaller than the total number of theoretical TF combinations (6).The CCTrCH is now defined by a set of allowed TFCs, i.e CCTrCH: TFCS= {TFC1,TFC2, TFC3} An example realization in time is shown in Figure 4.11

The Transport Format Combination present in a specific radio frame is denoted by agroup of bits TFC Indicator (TFCI), first introduced in Section 3.2.1 This is a key field ofdata for the receiver, as it indicates what Transport Blocks to look for in the radio frame

4.3.2.1 Transport Channel Types

TDD radio interface defines a number of Transport Channels, which may be classifiedinto two groups:

• Common Transport channels (where the transport channel is common to several UEs,which may be explicitly addressed for data transfer to a particular UE)

• Dedicated Transport channels (where the transport channel, i.e TFCS, Coding, TTI,etc., is dedicated to a particular UE)

TrCH3

Transmission Time Interval Transport Block

Transport Block Transport Block Transport Block

TF2

TF1 Transport Block

Transport Block TF1

Transport Block Transport Block

TF2 TF1

Transport Block TF1

There are six types of Common Transport channel types in TDD – RACH/T, FACH/

T, DSCH/T, USCH/T, BCH/T, PCH/T:

• The Random Access Channel (RACH/T) is a contention-based uplink channel used

for transmission of signaling messages and relatively small amounts of data, e.g forinitial access or non-real-time dedicated control or traffic data The TTI for RACH/Tchannel is fixed at 10 msecs, whereas the Transport Block size, Transport Block Setsize, CRC size and rate-matching parameters are not fixed by the standards However,

a CCCH message must be sent in a single RACH burst (Type 3 burst) and in a singleTransport Block (TB)

• The Forward Access Channel (FACH/T) is a common downlink transport channel

used for transmission of signaling messages and relatively small amounts of data It isused to carry control information to a mobile station when dedicated channels are notassigned or when shared channels are in use The FACH may also carry small amounts

of non-real-time traffic data

• The Downlink and Uplink Shared Channels (DSCH/T and USCH/T) are downlink

and uplink channels time shared by several UEs carrying dedicated control and/or trafficdata, as per allocations from higher layers

• The Broadcast Channel (BCH/T) is a downlink channel used for broadcast of system

and cell information into an entire cell

• The Paging Channel (PCH/T) is a downlink transport channel that is used to carry

control information to inactive or idle UEs It is also used to broadcast notification ofchange of BCCH information

• The PCH/T is divided into PCH blocks, each of which comprises of NPCH pagingsub-channels Each paging sub-channel is mapped onto two consecutive PCH frameswithin one PCH block To allow an efficient DRX for UE battery savings, Layer 3information to a particular UE is transmitted only in a paging sub-channel, which isassigned to the UE by higher layers Figure 4.12 shows PCH blocks, including PICHblocks introduced earlier

There is only one type of Dedicated transport channel, namely Dedicated Channel (DCH/T), which is a channel dedicated to one UE used in uplink or downlink The

Channel Coding for the Transport Channels is specified in Table 4.5

When multiplexing transport channels into a CCTrCH, some rules apply [2] Dedicatedtransport channels and common transport channels cannot be multiplexed into the same

Sub-Channel #0 Sub-Channel #1 Sub-Channel #NPCH-1

Layer 1 Communication 59

4.4 LAYER 1 COMMUNICATION

4.4.1 Layer 1 Processing

Layer 1 of the UE and the UTRAN communicate with each other by exchanging TransportBlocks (TB), which are delivered to/from Layer 2 once every Transmission Time Interval(10, 20, 40 or 80 ms) Figure 4.13 depicts how these Transport Blocks arising fromtwo Transport Channels are processed and multiplexed into a single CCTrCH and thenmapped to a Physical Channel [2, Section 4.2] A common example is the mapping ofDTCH/L:DCH/T and DCCH/L:DCH/T onto a single DPCH/P

Let Layer 2 submit on Transport Channel #1 a number (W≥ 1) of Transport Blockswith A bits each Transport Blocks are first block coded by appending a CRC (24, 16, 12,

8 or 0 bits) and then serially concatenated If necessary, padding bits are appended, so thatthe total number of bits is the minimum integer (X≥ 1) multiple of the length (B) of a so-called ‘Code Block’ The resulting bits are then segmented to produce X Code Blocks Bdepends upon the type of Channel Coding that is to be performed subsequently: B≤ 504bits for Convolutional Coding,≤5114 for Turbo Coding and Unlimited for ‘No-Coding’.Each of these Code Blocks is now ‘channel coded’ as per Table 4.5, using eitherConvolutional Coding, Turbo Coding or ‘No-Coding’, to produce X ‘Channel Blocks’ ofsize C bits each The total number of channel coded bits is XC

Since these bits have to be transmitted within an integer number of frames (F=TTI/10= 1, 2, 4 or 8), it may be necessary to pad extra bits, so that the number of bits,

say D, is an integer multiple of F That is, D= N * F, where N is an integer, equalingthe number of bits to be transmitted per Radio Frame

These D bits are now interleaved by first writing row-wise the data into a matrix with

F columns, permuting the columns and then reading out data column-wise See Chapter 3for the concept and TS 25.222 [2] for details

Similarly, Transport Channel #2 is processed to produce an integer number of RadioSegments The Radio Segments from Transport Channels 1 and 2 are and multiplexed to

Bit Scrambling

Physical Channel Segmentation

Radio Segments

Coded Composite Transport Channel

Physical Channel

Figure 4.13 Peer-to-Peer Communication of a Transport Block Set by Layer 1

form a Coded Composite Transport Channel, which is then mapped onto one or more ical Channels However, prior to multiplexing, the Radio Segments are ‘Rate Matched’,

Phys-so that the multiplexed Radio Segments fit exactly into the physical rePhys-sources allocated.The principle of Rate Matching is now explained

Let the physical channel resources allocated to the CCTrCH under consideration carry atotal number (Ndata) of bits The Rate Matching parameter, associated with each transportchannel, specifies its relative share of bits among the Ndata bits Let the share of the i-thTrCH be{Ndata(i) per Radio Segment} The number of bits (E) in the Radio Segment ofeach TrCH are now either punctured or repeated to equal Ndata(i) This process is calledRate Matching among the constituent TrCHs of a CCTrCH

Layer 1 Communication 61

Note that puncturing ‘some’ bits in each Radio Segment is acceptable, thanks to theerror-correcting capability provided by the channel coding However, puncturing doesdegrade the performance, so that limits are set by higher layers to the number of bits thatcan be punctured based on quality of service requirements

Another reason for ‘Rate Matching’ is to minimize or maintain the number of physicalchannels used when the number of data bits in a Transport Block changes in time.The multiplexed Radio Segments of the CCTrCH are now scrambled using a locallygenerated bit stream, defined by standards In case more than one physical channel is used(e.g two channelization codes with SF 16 in a timeslot), the scrambled bits are segmentedfor transmission on each physical channel

These bits are now interleaved for a second time, which is also a block interleaver as

in the first case That is, the input bits are read into a data matrix row-wise (some paddingbits may be needed here), columns permuted and output bits are read out column-wise(the padded bits are pruned here) The selection of the second interleaving scheme iscontrolled by higher layers Finally, these bits are mapped into the radio bursts of theallocated physical channels, after appropriate spreading

Figure 4.14 illustrates a service example, with 64 kbps DL data and associated cated in-band signaling at 2.5 kbps (both rates measured at the Transport Channel SAPbetween the MAC and PHY layers)

dedi-Specifically, data arrives at the transport channel DCH/T in Transport Blocks of size

1280 bits within a TTI of 20 ms (yielding 1280/20 = 64 kbps data rate) The in-band

signaling data arrives at a different transport channel DCH/T in Transport Blocks of size

100 bits within a TTI of 40 ms (yielding 100/20 = 2.5 kbps rate) Both these transport

channels are to be multiplexed into 5 physical channels, where each physical channel ischaracterized by a single timeslot supporting 5 channelization codes with SF= 16 andradio burst Type-1 (i.e Midamble 512 chips) 16 bits are used per timeslot for TFCI.Since the TTIs of the two Transport Channels to be multiplexed are different, themultiplexing has to be performed over the larger TTI, namely 40 ms, which contains twoTransport Blocks of Traffic Data and one Transport Block of Signaling Data Each of theTraffic Data Transport Blocks is CRC coded with 16 CRC bits, and further coded withRate 1/3 Turbo Code, which increases the size 3- fold 12 Trellis termination bits areadded and interleaved The resulting 3900 bits are split into two radio segments, so thatthey may be transmitted over two radio frames

Similarly, the Signaling Data Transport Block is CRC coded with 12 CRC bits, andConvolutionally coded with Rate 1/2 and 8 Trellis Coding bits The resulting 240 bits areinterleaved

The Radio Segments corresponding to the Traffic and Signaling Data are now punctured

as shown in order to produce four 1204 bit blocks, which are then interleaved a secondtime and packed into five radio bursts (multicode transmission) after inserting TCFI fields

4.4.2 Inter-Layer Communication

The Physical Layer interfaces with the Medium Access Control (MAC) sublayer of Layer

2 and the Radio Resource Control (RRC) sublayer of Layer 3 as depicted in Figure 4.15.Communication between the Physical Layer and MAC is performed by means of PHYprimitives The PHY primitives enable the transfer of transport blocks over the radio inter-face and indicate the status of Layer 1 to Layer 2 Communication between the Physical

Information data 1280

1280 CRC attachment

12 Trellis-Termination

8 Tail CRC MAC-Header

TF CI TF CI

TF CI

TF CI

TF CI TF CI

TF CI TF CI

TF CI TF CI

Figure 4.14 Service Example of 64 kbps Traffic and 2.5 kbps Signaling Data

Physical Layer

Medium Access Control (MAC) Radio Resource Control (RRC)

PHY primitives Layer 1

Layer 2 Structure 63

Layer and RRC is performed by means of CPHY primitives The CPHY primitives enablethe control of the configuration of the Physical Layer Since these primitives are only forinternal communications between layers in the UE or the Network, they are not subject

to standardization and are vendor dependent As such, what follows should be considered

as examples only

The PHY primitives include primitives to request and to indicate the receipt of Layer

1 SDUs respectively and are submitted every TTI for each Transport Channel

There are two classes of CPHY primitives, namely Status primitives and Control itives Among the Status primitives are the Synchronization primitives, which indicate tothe RRC that the Layer 1 synchronization is achieved or lost The Measurement primitivesenable RRC to request measurements and the Physical Layer to report measurements For

prim-UE, these primitives specify measurements such as: PCCPCH RSCP (Received SignalCode Power), Timeslot ISCP, SIR (Signal to Interference Ratio), Carrier RSSI (ReceivedSignal Strength Indicator), Transport Channel BLER (Block Error Rate), TransmittedPower, etc For the UTRAN, the measurement parameters include: Received Total Wide-band Power, Transmitted Carrier Power, Transmitted Code Power, Transport ChannelBER, Rx Timing Deviation, Timeslot ISCP, RSCP, Round Trip time, SIR, PRACH/P Prop-agation Delay, etc The CPHY Control primitives include those for setting up/releasingTransport Channels, and Radio Links

4.5 LAYER 2 STRUCTURE

As shown in Figure 4.3, the structure of Layer 2 (Radio Link Layer) consists of a number

of protocol entities, namely MAC, RLC, PDCP, and BMC Furthermore, Layer 2 providesServices to Layer 3 via Radio Bearers The intermediate Service Access Points betweenthe MAC and RLC protocol entities are referred to as Logical Channels

4.5.1 Logical Channels

Logical Channels are classified according to the type of information that is transferred.The set of Logical Channel types is listed in Table 4.1, and they are briefly described here.The first group of Logical Channels is Control channels, which are used for transfer ofcontrol plane information only:

• The Broadcast Control Channel (BCCH/L) is a downlink channel for broadcasting

system control information

• The Paging Control Channel (PCCH/L) is a downlink channel that transfers paging

information This channel is used when the network does not know the location cell ofthe UE, or when the network knows the location cell of the UE but the UE does nothave a signaling connection to the network (Specifically, the Paging Control Channel

is used when the UE is in the CELL PCH or URA PCH state of RRC connected mode

or UE is in RRC idle mode These are described later in Section 4.7.1.)

• The Common Control Channel (CCCH/L) is a bi-directional channel for transmitting

control information between the network and UEs This channel is commonly used bythe UEs having no RRC connection with the network and by the UEs when accessing

a new cell after cell reselection

• The Dedicated Control Channel (DCCH/L) is a point-to-point bi-directional

chan-nel that transmits dedicated control information between a UE and the network Thischannel is established through RRC connection set-up procedure

• The Shared Channel Control Channel (SHCCH/L) is a bi-directional channel that

transmits control information for uplink and downlink shared channels between networkand UEs

The second group of Logical Channels is Traffic Channels, which are used for the transfer

of user plane information only:

• Dedicated Traffic Channel (DTCH/L) is a point-to-point channel, dedicated to one

UE, for the transfer of user information A DTCH can exist in both uplink and downlink

• Common Traffic Channel (CTCH/L) The Common Traffic Channel (CTCH/L) is a

point-to-multipoint unidirectional channel for transfer of dedicated user information forall or a group of specified UEs It is used primarily for sending Broadcast and Multicastinformation

While the information carried by each of above logical channels is self-evident, theinformation carried by the Broadcast Channel deserves elaboration The Broadcast LogicalChannel carries critical system information that is needed by the UEs, the details of whichare included in Appendix 4.1

4.5.2 Radio Bearers

Radio Bearer is a service abstraction between Layer 3 and Layer 2 It represents a datastream provided by the RLC layer for transfer of user data between User Equipment andServing RNC A Radio Bearer is specified by the RLC, PDCP and MAC information aswell as information about mapping the RB to Logical and Transport Channels as follows[6, Sections 10.3.4.16–10.3.4.24]:

• RLC Size and Mode (AM/UM/TM)

• PDCP Information

• Logical Channel Identity

• MAC Logical Channel Priority

• Transport Channel Type and Identity

• Transport Format Parameters

The RLC modes AM/UM/TM refer to Acknowledged Mode/Unacknowledged Mode/Transparent Mode and are further described in Section 4.6.2 A Radio Bearer is identified

by a number from 0–31 [6] Radio Bearers RB0 through RB3 (and optionally RB4) areused for RRC Signaling Messages and hence are referred as Signaling Radio Bearers.Their typical use is as follows:

• Signaling Radio Bearer RB0 is used for all messages sent on the CCCH/L with RLC-TMfor Uplink and RLC-UM for Downlink

The UE and UTRAN select which Signaling Radio Bearer to use according to the messagetype to be sent and the type of Logical Channel (DCCH/L or CCCH/L) For example,RB0 is used by the UE in idle mode to send an ‘RRC Connection Request’ In connectedmode, the UE uses RB1, RB2 or RB3, with the exception of the RRC messages ‘CellUpdate’ and ‘URA Update’, which are sent in RB0 (CCCH) (These RRC messages areexplained further in Section 4.7.1).

4.6.1 Medium Access Control (MAC) Protocol

4.6.1.1 MAC Architecture

The MAC layer controls the mapping of various Logical Channels onto TransportChannels Depending on the type of Transport Channel being controlled, three types

of MAC protocol entities are identified They are termed d, c/sh and

MAC-b for Dedicated, Common/Shared and Broadcast Transport Channels respectively The

Layer N SDU = Layer (N + 1) PDU

One Layer (N + 1) PDU

SDU Processing

Layer N PDU generation

One or More Layer N

FACH RACH

DCCH DTCH DTCH

DSCH DCH DCH CTCH MAC Control

USCH

MAC-sh MAC-c

CCCH SHCCH PCCH

Iur or local DCH DCH

MAC-d

USCH

MAC-sh MAC-c

CCCH CTCH SHCCH PCCH

FACH PCH

Common/Shared Transport Channels include PCH/T, FACH/T, RACH/T, DSCH/T andUSCH/T Figure 4.17 depicts the architecture for MAC-d and MAC-c/sh in the UE and

in the RNC Observe that there are multiple Dedicated MAC protocol entities at the RNC,each instance corresponding to a particular UE

4.6.1.2 MAC Services and Functions

MAC Services to upper layers are:

1 Data transfer: Two Peer MAC entities communicate by exchanging MAC PDUs in

a transparent manner (That is, there is no error correction, no retransmissions, etc.These are services provided by higher (sub-)layers.)

2 Reallocation of radio resources and MAC parameters: This service performs the cution of radio resource reallocation at the request of the RRC protocol and change