Content for TS 43.064 Word version: 16.0.0

5.1 General 5.2 Packet Common Control Channels (PCCCH and CPCCCH) 5.2a MBMS Common Control Channels (MPRACH) 5.2b Extended Coverage Common Control Channels (EC-CCCH) 5.3 Packet Broadcast Control Channel (PBCCH and CPBCCH) 5.3a Compact Frequency Correction Channel (CFCCH) 5.3b Compact Synchronization Channel (CSCH) 5.3c Extended Coverage Broadcast Control Channel (EC-BCCH) 5.4 Packet Timing advance Control Channel (PTCCH) 5.5 Packet Traffic Channels 5.6 Downlink resource sharing 5.7 Uplink resource sharing
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5 Mapping of packet data logical channels onto physical channels

5.1 General

Different packet data logical channels can be mapped to the same physical channel (i.e. PDCH). The sharing of the physical channel is based on blocks of 4 consecutive bursts of one specific PDCH in 4 consecutive TDMA frames (for basic TTI configuration) or 2 bursts on each PDCH within a PDCH pair in 2 consecutive TDMA frames (for a reduced TTI configuration), except for PTCCH. In case of EC operation, when using blind physical layer transmissions on EC-PDTCH and EC-PACCH, a variation of the BTTI configuration is used wherein the sharing of the physical channels is different depending on the Coverage Class and the number of PDCHs assigned to an EC TBF (determined based on whether the network supports the allocation of 2 or 4 consecutive PDCHs, see TS 44.018), and

for an EC TBF assigned four consecutive PDCHs, is for:
- CC2 based on blocks of 16 bursts of 4 PDCHs in 4 consecutive TDMA frames
- CC3 based on blocks of 32 bursts of 4 PDCHs over 8 or 9 TDMA frames (depending on idle frame placement)
- CC4 based on blocks of 64 bursts of 4 PDCHs over 16 or 17 TDMA frames (depending on idle frame placement)
- CC5 in uplink based on blocks of 192 bursts of 4 PDCHs over 52 TDMA frames.
for an EC TBF assigned two consecutive PDCHs, is for:
- CC2 based on blocks of 16 bursts of 2 PDCHs over 8 or 9 TDMA frames (depending on idle frame placement)
- CC3 based on blocks of 32 bursts of 2 PDCHs over 16 or 17 TDMA frames (depending on idle frame placement).
- CC4 based on blocks of 64 bursts of 2 PDCHs over 34 TDMA frames
- CC5 in uplink based on blocks of 192 bursts of 2 PDCHs over two 52 TDMA frames.

When blind physical layer transmissions are used on EC-PDTCH, the BTTI mapping of the four bursts of a radio block onto four consecutive TDMA frames is used and repeated on two or four PDCHs and (for the higher Coverage Classes) during multiple basic TTIs.

As an exception, when an uplink EC TBF is mapped onto two consecutive PDCHs, another variation of the BTTI configuration is used wherein the blind physical layer transmissions on an EC-PDTCH are applied on a burst level, i.e., all blind physical layer transmissions of one burst in a radio block are transmitted before the blind physical layer transmissions of the next burst in the radio block are transmitted (see sub-clause 6.1.2 and TS 45.003). The latter is referred to as compact burst mapping.

The TBFs using reduced TTI and the TBFs using basic TTI sharing the same physical channel need to coexist within the overall block structure specified for the basic TTI. As such, for each assigned PDCH pair corresponding to a reduced TTI TBF, two consecutive reduced TTI radio blocks must be allocated within the time period spanned by a single radio block sent using the basic TTI. Each of the two reduced TTI radio blocks in this block structure could be allocated to different MSs or one of the reduced TTI blocks could be empty if not needed. The mapping in frequency of PDCH on to the physical channel shall be as defined in TS 45.002.

A PDCH may be either full-rate (PDCH/F) or half-rate (PDCH/H). PDCH/H is only applicable to DTM. See TS 45.002. PDCH/H is not applicable for a reduced TTI configuration.

GPRS, EGPRS and EGPRS2 employ the same physical layer, except for the PDTCH. EC-GSM-IoT employs a different physical layer by the use of logical channels supporting extended coverage, EC-channels. EC-GSM-IoT will also make use of FCCH for synchronization purposes and may also make use of RACH and AGCH CC1 has been selected, which employs the same physical layer as GPRS, EGPRS and EGPRS2.

On PRACH, CPRACH, MPRACH, EC-RACH and PTCCH/U, access bursts are used. On EC-RACH CC5, Extended Synchronization Access Bursts or Extended Dual slot Access Bursts are used (see TS 45.002). On all other packet data logical channels, radio blocks comprising 4 normal bursts are used. The only exception is some messages on uplink (EC )PACCH which comprise 4 consecutive access bursts (to increase robustness).

5.2 Packet Common Control Channels (PCCCH and CPCCCH) Word‑p. 24

At a given time, the logical channels of the PCCCH are mapped on different physical resources than the logical channels of the CCCH.

The PCCCH and CPCCCH do not have to be allocated permanently in the cell. Whenever the PCCCH is not allocated, the CCCH shall be used to initiate a packet transfer. For Compact, CPCCCH shall be allocated.

One given MS may use only a subset of the PCCCH and CPCCCH, the subset being mapped onto one physical channel (i.e. PDCH).

The PCCCH, when it exists:

is mapped on one or several physical channels according to a 52-multiframe, In that case the PCCCH, PBCCH and PDTCH share same physical channels (PDCHs).

The existence and location of the PCCCH shall be broadcast on the cell. (See sub-clause 3.2a).

Since GSM phase 1 and phase 2 MS can only see and use the CCCH, the use on the PCCCH can be optimised for GPRS e.g. a PRACH of 11 bits can be used on uplink.

For Compact, one radio frequency channel of the cell allocation shall be used to carry synchronization information and the CPBCCH, this shall be known as the primary Compact carrier. All other radio frequency channels of the cell allocation shall be known as secondary Compact carriers.

For primary and secondary Compact carriers, CPCCCHs shall be allocated on only one timeslot (which is associated with a time group as defined in TS 45.002). This time group is known as the serving time group and rotates over odd timeslot numbers as follows: 7, 5, 3, 1, 7, 5, …. The CPCCCH is mapped according to a Compact 52-multiframe and the serving time group rotation occurs between frame numbers (FN) mod 52 = 3 and 4.

5.2.1 Packet Random Access Channel (PRACH and CPRACH) Word‑p. 25

The PRACHand CPRACH are mapped on one or several physical channels. The physical channels on which the PRACH is mapped are derived by the MS from information broadcast on the PBCCH or BCCH. The physical channels on which the CPRACH is mapped are derived by the MS from information broadcast on the CPBCCH.

PRACH and CPRACH are determined by the Uplink State Flag marked as free that is broadcast continuously on the corresponding downlink (see subclause 6.6.4.1). Additionally, a predefined fixed part of the multiframe structure for PDCH can be used as PRACH or CPRACH only and the information about the mapping on the physical channel is broadcast on PBCCH or CPBCCH. During those time periods an MS does not have to monitor the USF that is simultaneously broadcast on the downlink.

5.2.2 Packet Paging Channel (PPCH and CPPCH)

The PPCH and CPPCH are mapped on one or several physical channels. The exact mapping on each physical channel follows a predefined rule (see subclause 6.1.2), as it is done for the PCH.

The physical channels on which the PPCH or CPPCH are mapped, as well as the rule that is followed on the physical channels, are derived by the MS from information broadcast on the PBCCH or CPBCCH.

5.2.3 Packet Access Grant Channel (PAGCH and CPAGCH)

The PAGCH and CPAGCH are mapped on one or several physical channels. The exact mapping on each physical channel follows a predefined rule (see subclause 6.1.2).

The physical channels on which the PAGCH or CPAGCH are mapped, as well as the rule that is followed on the physical channels, are derived by the MS from information broadcast on the PBCCH or CPBCCH.

5.2.4 Void

5.2a MBMS Common Control Channels (MPRACH) |R6|

The MPRACH is mapped on one physical channel. The physical channel on which the MPRACH is mapped is indicated to the MS by the network.

The network indicates the value of the USF associated with the MPRACH on a particular PDCH in the notification message. The MPRACH is determined by the Uplink State Flag, which is broadcast on the corresponding downlink (see subclause 6.6.4.1), marked as the value indicated by the network.

5.2b Extended Coverage Common Control Channels (EC-CCCH) |R13| Word‑p. 26

5.2b.1 General

The logical channels of the EC-CCCH are mapped on different physical resources than the logical channels of the CCCH.

The existence of the EC-CCCH is indicated by the presence of the EC-SCH.

The EC-CCCH is mapped on one or several physical channels according to a 51-multiframe structure.

5.2b.2 Extended Coverage Random Access Channel (EC-RACH)

The EC-RACH is mapped on one or several physical channels. The physical channel(s) on which the EC-RACH is mapped are derived by the MS from the EC SI broadcasted on the EC-BCCH, see TS 45.002.

Depending on the EC SI information a MS will transmit the EC-RACH using a 1 TS or 2 TS EC-RACH mapping, see TS 45.002.

5.2b.3 Extended Coverage Paging Channel (EC-PCH)

The EC-PCH is mapped on one or several physical channels. The exact mapping on each physical channel follows a predefined rule, see TS 45.002.

The physical channels on which the EC-PCH is mapped, are derived by the MS from the EC SI broadcasted on the EC-BCCH, see TS 45.002.

5.2b.4 Extended Coverage Access Grant Channel (EC-AGCH)

The EC-AGCH is mapped on one or several physical channels. The exact mapping on each physical channel follows a predefined rule, as it is done for the AGCH, see TS 45.002.

The physical channels on which the EC-AGCH is mapped, as well as the rule that is followed on the physical channels, are derived by the MS from the EC SI broadcasted on the EC-BCCH, see TS 45.002.

5.2b.5 Extended Coverage Paging Indication Channel (EC-PICH) |R15|

The EC-PICH is mapped on one or several physical channels. The exact mapping on each physical channel follows a predefined rule see TS 45.002.

The EC-PICH provides the paging indication for specific paging blocks in the paging multiframe for higher coverage classes CC3 and CC4, see TS 45.002.

5.3 Packet Broadcast Control Channel (PBCCH and CPBCCH)

The PBCCH and CPBCCH shall be mapped on one or several physical channels. The exact mapping on each physical channel follows a predefined rule (see subclause 6.1.2), as it is done for the BCCH. For Compact, CPBCCH shall be allocated. CPBCCH and BCCH are mutually exclusive.

The existence of the PCCCH, and consequently the existence of the PBCCH, is indicated on the BCCH. (See sub-clause 3.2a).

The CPBCCH shall be mapped on only one timeslot (which is associated with a time group as defined in TS 45.002). This time group is known as the serving time group and rotates over odd timeslot numbers as follows: 7, 5, 3, 1, 7, 5, …. The CPBCCH is mapped according to a Compact 52-multiframe and the serving time group rotation occurs between frame numbers (FN) mod 52 = 3 and 4. The exact mapping follows a predefined rule (see subclause 6.1.2).

5.3a Compact Frequency Correction Channel (CFCCH) Word‑p. 27

The CFCCH is the same as the FCCH with one exception — the FCCH is mapped onto a 51-multiframe as defined in TS 45.002.

5.3b Compact Synchronization Channel (CSCH)

The CSCH is similar to the SCH. The major difference is that the SCH is mapped onto a 51-multiframe as defined in TS 45.002. This results in a different layout for the reduced TDMA frame number (RFN).

5.3c Extended Coverage Broadcast Control Channel (EC-BCCH) |R13|

The EC-BCCH shall be mapped on one or more physical channels. The exact mapping on each physical channel follows a predefined rule, see TS 45.002.

The existence of the EC-BCCH is indicated by the presence of the EC-SCH.

5.4 Packet Timing advance Control Channel (PTCCH)

Two defined frames of multiframe are used to carry PTCCH (see subclause 6.1.2). The exact mapping of PTCCH/U sub-channels and PTCCH/D shall be as defined in TS 45.002.

On PTCCH/U, access bursts are used. On PTCCH/D, four normal bursts comprising a radio block are used.

In a downlink dual or multi carrier configuration, an MS shall be assigned a PTCCH/D channel and a PTCCH/U sub-channel on one radio frequency channel only.

5.5 Packet Traffic Channels

5.5.1 Packet Data Traffic Channel (PDTCH)

A PDTCH is mapped onto one physical channel (PDCH) or, in the case of RTTI configurations (see subclause 3.3.5), two physical channels (PDCH-pair).

For one TBF, up to eight PDCHs or four PDCH-pairs, with different timeslot numbers but with the same frequency parameters, may be assigned to one MS at the same time. In the case of p-t-m transmission for MBMS, up to five downlink PDCH/Fs, with different timeslot numbers but with the same frequency parameters, may be assigned for one broadcast or multicast session.

In the case of a downlink dual carrier configuration, up to 16 PDCHs or eigth PDCH-pairs may be assigned to one TBF at the same time.

In case of a downlink multi carrier configuration, up to 16 carriers corresponding to 128 PDCH or 64 PDCH-pairs may be assigned to one TBF at the same time.

5.5.1a Extended Coverage Packet Data Traffic Channel (EC-PDTCH) |R13|

An EC-PDTCH is mapped onto one or, in case blind physical layer transmissions are used, four consecutive physical channel(s) (i.e. PDCHs) and shall always use basic TTI configuration.

For one EC TBF, one to eight PDCHs, with different timeslot numbers but with the same frequency parameters, may be assigned to one MS at the same time when CC1 is used (i.e. with no blind physical layer transmissions) in the direction of the TBF. When blind physical layer transmissions are used, an EC TBF is mapped onto four PDCHs where the PDCHs shall be consecutive.

5.5.2 Packet Associated Control Channel (PACCH) Word‑p. 28

PACCH is dynamically allocated on a radio block basis on the same physical channel(s) used for carrying PDTCHs. However, one block PACCH allocation is also used on the physical channel carrying only PCCCH, when the MS is polled to acknowledge the initial assignment message.

PACCH is of a bi-directional nature, i.e. it can dynamically be allocated both on the uplink and on the downlink regardless on whether the corresponding PDCH assignment is for uplink or downlink.

The PACCH shall have the same TTI configuration as the TBF with which it is associated.

If an MS is assigned one or more PDCH(s) /PDCH pair(s) on the uplink then, in the case of dynamic allocation (see subclause 6.6.4.4) the corresponding downlink timeslots/PDCH pair(s) have to be continuously monitored by the MS for possible occurrences of PACCH; in the case of extended dynamic allocation (see subclause 6.6.4.4), only the downlink timeslot/PDCH pair(s) corresponding to the lowest numbered assigned uplink timeslot has to be continuously monitored by the MS for possible occurrences of PACCH. The MS can use an uplink allocation for sending PACCH blocks whenever needed.

In case of a downlink dual carrier configuration, PACCH blocks may be sent on the downlink on both radio frequency channels simultaneously.

In case of a downlink multi carrier configuration, PACCH blocks may be sent on all assigned downlink radio frequency channels simultaneously.

If an MS is assigned one or more PDCH(s) /PDCH pair(s) on the downlink, every occurrence of an uplink PACCH block is determined by polling in one of the preceding downlink blocks (transferred on the same PDCH(s)). The network can use the downlink assignment for sending PACCH blocks whenever needed.

5.5.2a Extended Coverage Packet Associated Control Channel (EC-PACCH) |R13|

An EC-PACCH is mapped onto one or four physical channel(s) (i.e. PDCHs) and shall always use basic TTI configuration. The number of physical channels to use is dependent on the Coverage Class used in the direction the EC-PACCH is transmitted, see TS 45.002.

On the uplink, Fixed Uplink Allocation of EC-PDTCH is used, see subclause 6.6.4.1.4. This implies that the MS shall not monitor the USF on the DL PDCH for uplink allocation. For the duration of the Fixed Uplink Allocation the MS shall not monitor any downlink timeslots for EC-PACCH. After the duration of the Fixed Uplink Allocation, downlink timeslot(s) are monitored by the MS for possible occurrences of EC-PACCH. During the Fixed Uplink Allocation the MS shall not use the allocated uplink resources for sending EC-PACCH blocks. Uplink EC-PACCH blocks shall only be sent by the MS when preceded by polling in downlink block(s).

On the downlink, dynamic allocation of EC-PDTCH is used. If an MS is assigned one or more PDCH(s) on the downlink, every uplink allocation of an EC-PACCH block is determined by polling related control parameters in the preceding downlink block(s). The network can use the downlink assignment for sending EC-PACCH blocks whenever needed.

5.6 Downlink resource sharing Word‑p. 29

Different packet data logical channels can be multiplexed on the downlink on the same physical channel (i.e. PDCH). See details in TS 45.002. The type of message which is indicated in the radio block header allows differentiation between the logical channels. Additionally, the MS identity allows differentiation between PDTCHs and PACCHs assigned to different MSs. The MS identity also allows differentiation between TBFs and p-t-m MBMS bearers.

In addition, in dual transfer mode the network may dedicate a PDCH exclusively to an MS (i.e. the only PDTCH mapped onto that PDCH will be the one assigned to that MS). Even in the case of exclusive allocation, the network shall use the MS identity and the type of message in the radio block header.

5.7 Uplink resource sharing

Different packet data logical channels can be multiplexed on the uplink of the same physical channel (i.e. PDCH). See details in TS 45.002. The type of message which is indicated in the radio block header, allows differentiation between the logical channels. Additionally, the MS identity allows differentiation between PDTCHs and PACCHs assigned to different MSs.

In addition, in dual transfer mode the network may dedicate a PDCH exclusively to one MS.