4.2.13 Multiplexing of different transport channels onto one CCTrCH, and mapping of one CCTrCH onto physical channels
25.2223GPPMultiplexing and channel coding (TDD)Release 17TS
Different transport channels can be encoded and multiplexed together into one Coded Composite Transport Channel (CCTrCH). The following rules shall apply to the different transport channels which are part of the same CCTrCH:
1) Transport channels multiplexed into one CCTrCh shall have co-ordinated timings. When the TFCS of a CCTrCH is changed because one or more transport channels are added to the CCTrCH or reconfigured within the CCTrCH, or removed from the CCTrCH, the change may only be made at the start of a radio frame with CFN fulfilling the relation
CFN mod Fmax = 0,
where Fmax denotes the maximum number of radio frames within the transmission time intervals of all transport channels which are multiplexed into the same CCTrCH, including any transport channels i which are added reconfigured or have been removed, and CFN denotes the connection frame number of the first radio frame of the changed CCTrCH.
After addition or reconfiguration of a transport channel i within a CCTrCH, the TTI of transport channel i may only start in radio frames with CFN fulfilling the relation
CFNi mod Fi = 0.
2) Different CCTrCHs cannot be mapped onto the same physical channel.
3) One CCTrCH shall be mapped onto one or several physical channels.
4) Dedicated Transport channels and common transport channels cannot be multiplexed into the same CCTrCH.
5) For the common transport channels, only the FACH and PCH may belong to the same CCTrCH.
6) Each CCTrCH carrying a BCH shall carry only one BCH and shall not carry any other Transport Channel.
7) Each CCTrCH carrying a RACH shall carry only one RACH and shall not carry any other Transport Channel.
Hence, there are two types of CCTrCH.
CCTrCH of dedicated type, corresponding to the result of coding and multiplexing of one or several DCH.
CCTrCH of common type, corresponding to the result of the coding and multiplexing of a common channel, i.e. RACH and USCH in the uplink and DSCH, BCH, FACH or PCH in the downlink, respectively.
Transmission of TFCI is possible for CCTrCH containing Transport Channels of:
– dedicated type;
– USCH type;
– DSCH type;
– FACH and/or PCH type.
4.2.13.1 Allowed CCTrCH combinations for one UE
4.2.13.1.1 Allowed CCTrCH combinations on the uplink
The following CCTrCH combinations for one UE are allowed, also simultaneously:
1) several CCTrCH of dedicated type;
2) several CCTrCH of common type.
4.2.13.1.2 Allowed CCTrCH combinations on the downlink
The following CCTrCH combinations for one UE are allowed, also simultaneously:
3) several CCTrCH of dedicated type;
4) several CCTrCH of common type.