14.10 Calculated Transport Format Combination
25.3313GPPProtocol specificationRadio Resource Control (RRC)Release 17TS
The Calculated Transport Format Combination (CTFC) is a tool for efficient signalling of transport format combinations.
Let I be the number of transport channels that are included in the transport format combination. For DCHs, all configured DCHs are included in the transport format combination. Each transport channel TrCHi, i = 1, 2, …, I, has Li transport formats, i.e. the transport format indicator TFIi can take Li values, .
Define , where i = 1, 2, …, I, and L0 = 1.
Let TFC(TFI1, TFI2, …, TFII) be the transport format combination for which TrCH1 has transport format TFI1, TrCH2 has transport format TFI2, etc. The corresponding CTFC(TFI1, TFI2, …, TFII) is then computed as:
.
For FACH and PCH transport channels, "TrCH1" corresponds to the transport channel listed at the first position in IE "FACH/PCH information" in IE "Secondary CCPCH System Information", "TrCH2" corresponds to the transport channel listed at the second position in IE "FACH/PCH information" and so on.
For all other transport channels in FDD and for all configured transport channels of the same transport channel type (i.e. DCH, DSCH, USCH) in TDD, "TrCH1" corresponds to the transport channel having the lowest transport channel identity in the transport format combination mapped to the TFCI field. "TrCH2" corresponds to the transport channel having the next lowest transport channel identity, and so on.
14.10.1 Default TFCS for MBMS
14.10.1.1 S-CCPCH configuration including a FACH carrying MSCH
In case the S-CCPCH configuration includes a FACH carrying MSCH, the default TFCS is defined according to the following:
Let TrCH 1 be the FACH carrying MSCH, TrCH 2 be the first TrCH carrying MTCH listed in the IE "TrCh information list", TrCH 3 be the second TrCH carrying MTCH listed in the IE "TrCh information list" etc. and let TrCH I be the last TrCH carrying MTCH listed in the IE "TrCh information list".
Each transport channel TrCHi, i = 1, 2, …, I, has Li transport formats, i.e. the transport format indicator TFIi can take Li values.
Each transport format combination set is defined by the transport formats of each transport channel mapped on this S-CCPCH:
TFC = (TFI1, TFI2, …, TFII).
The "MBMS implicit TFCS" contains then the following set of TFCs:
TFCS = {(0,0,…,0),(0,1,…,0),…,(0,L2,…,0),(0,0,1,…,0),…,(0,0,L3,…,0),…,(0,0,0,…,1),…,(0,0,0,…,LI),
(1,0,…,0),(1,1,…,0),…,(1,L2,…,0),(1,0,1,…,0),…,(1,0,L3,…,0),…,(1,0,0,…,1),…,(1,0,0,…,LI),
(2,0,…,0),…,(L1,0,…,0)}
14.10.1.2 S-CCPCH configuration not including a FACH carrying MSCH
In case the S-CCPCH configuration does not include a FACH carrying MSCH, the default TFCS is defined according to the following:
Let TrCH 1 be the first TrCH listed in the IE "TrCh information list", TrCH 2 be the second TrCH listed in the IE "TrCh information list" etc. and let TrCH I be the last TrCH listed in the IE "TrCh information list".
Each transport channel TrCHi, i = 1, 2, …, I, has Li transport formats, i.e. the transport format indicator TFIi can take Li values.
Each transport format combination set is defined by the transport formats of each transport channel mapped on this S-CCPCH:
TFC = (TFI1, TFI2, …, TFII).
The "MBMS implicit TFCS" contains then the following set of TFCs:
TFCS = {(0,…,0), (1,…,0),…,(L1,…,0),(0,1,…,0),…,(0,L2,…,0),…,(0,0,…,1),…,(0,0,…,LI)}