8 Flexible layer one
3GPP45.002GSM/EDGE Multiplexing and multiple access on the radio pathRelease 17TS
8.1 General
With FLO, the physical layer offers transport channels to upper layers. In each direction, one or several transport channels can be processed and multiplexed together by the same coding and multiplexing unit. The detailed functions of the coding and multiplexing unit are defined in 3GPP TS 45.003.
8.2 Transport channels
The offered transport channels are Dedicated CHannels (DCHs). DCHs are unidirectional and used to carry user or control data on DBPSCH. Depending on the channel mode of the DBPSCH on which they are used, two general forms of DCH are defined:
i) Full rate DCH (DCH/F). This channel carries information at a maximum gross rate of 68.5 kbit/s and shall only be used on DBPSCH/F.
ii) Half rate DCH (DCH/H). This channel carries information at a maximum gross rate of 34.1 kbit/s and shall only be used on DBPSCH/H.
8.3 Mapping of transport channels onto physical channels
8.3.1 General
The detailed mapping of transport channels onto physical channels is defined in the following sections. Subclause 8.3.2 defines the mapping from TDMA frame number (FN) to radio frequency channel (RFCH). Subclause 8.3.3 defines the mapping of the physical channel onto TDMA frame number. Subclause 8.3.4 lists the permitted channel combinations and subclause 8.3.5 defines the multislot configurations.
8.3.2 Mapping in frequency of transport channels onto physical channels
The mapping from TDMA frame number (FN) to radio frequency channel (RFCH) is done as specified in subclause 6.2.
8.3.3 Mapping in time of transport channels onto physical channels
For each DBPSCH using FLO, every transmission time interval (TTI), one or several DCHs are processed and multiplexed together by the same coding and multiplexing unit. The single output data block from the coding and multiplexing unit is called a radio packet and it shall be mapped onto one and only one DBPSCH. The radio packet is then interleaved on bursts according to the channel mode and interleaving scheme chosen by layer 3 (see 3GPP TR 45.902 and 3GPP TS 44.118).
The mapping in time of radio packets is defined in table 8.3.3 below where the columns headed:
i) "DBPSCH configuration" defines the configuration of the DBPSCH in terms of channel mode (full rate or half rate) and interleaving scheme (4 bursts rectangular, 8 bursts diagonal or 4 bursts diagonal).
ii) "Sub‑channel number" identifies the particular sub‑channel being defined where a DBPSCH supports more than one channel of this type.
iii) "Direction" defines whether the mapping given applies identically to downlink and uplink (D&U), or to downlink (D) or uplink (U) only.
iv) "Allowable timeslots assignments" defines whether FLO can be supported on, or assigned to, any of the timeslots, or only on specific timeslots.
v) "Allowable RF channel assignments" defines whether FLO can use any or all of the radio frequency channels in the cell allocation (CA), or only the BCCH carrier (C0). It should be noted that any allocated channel Cx within CA could be any radio frequency channel, and that no ordering of radio frequency channel number is implied. For example, allocated channel C0 need not have the lowest radio frequency channel number of the allocation.
vi) "Burst type" defines which type of burst as defined in clause 5.2 is to be used for the physical channel.
vii) "Repeat length in TDMA frames" defines how many TDMA frames occur before the mapping for the interleaved radio packets repeats itself.
viii) "Interleaved radio packet TDMA frame mapping" defines, within the parentheses, the TDMA frames used by each interleaved radio packet (e.g. 0..3). The numbers given equate to the TDMA frame number (FN) modulo the number of TDMA frames per repeat length; Therefore, the frame is utilized when:
TDMA frame mapping number = (FN)mod (repeat length)
Where there is more than one radio packet shown, each radio packet is given a separate designation e.g. B0, B1. Where diagonal interleaving is employed then all of the TDMA frames included in the radio packet are given, and hence the same TDMA frame number can appear more than once (see 3GPP TS 45.003).
Table 8.3.3: Mapping of radio packets onto physical channels
DBPSCH Sub‑channel Direction Allowable time slot Allowable RF channel Burst Repeat length Interleaved radio packet
Configuration number assignments assignments type in TDMA frames TDMA frame mapping
full rate channel (DBPSCH/F)
8 bursts diagonal interleaving D&U 0 … 7 C0 … Cn NB1 13 B0(0…7), B1(4…11), B2(8…11,0…3)
full rate channel (DBPSCH/F)
4 bursts rectangular interleaving D&U 0 … 7 C0 … Cn NB1 13 B0(0…3), B2(4…7), B3(8…11)
half rate channel (DBPSCH/H)
4 bursts diagonal interleaving 0 D&U 0 … 7 C0 … Cn NB1 13 B0(0,2,4,6), B1(4,6,8,10), B2(8,10,0,2)
1 B0(1,3,5,7), B1(5,7,9,11), B2(9,11,1,3)
NOTE 1: An Access Burst (AB) is used on the uplink during handover.
8.3.4 Permitted channel combinations onto a basic physical subchannel
Four principles regulate the channel combinations with FLO:
– DCHs shall only be mapped on DBPSCH.
– On the same DBPSCH, a maximum of 8 DCHs may be allocated.
– In the same radio packet, a maximum of 4 DCHs may be processed and multiplexed together by the coding and multiplexing unit.
– With the exception of the SACCH, logical channels and transport channels shall not be mapped onto the same DBPSCH.
The following are the permitted ways in which channels can be combined onto one DBPSCH/F for one MS:
f1) DCH/F(s) + SACCH/TF
f2) DCH/F(s) + SACCH/M
f3) DCH/F(s) + SACCH/MD
f4) DCH/F(s) + SACCH/TPF + EPCCH/F
f5) DCH/F(s) + SACCH/MP + EPCCH/M
f6) DCH/F(s) + SACCH/MPD + EPCCH/MD
NOTE 1: the number of DCHs may be different in uplink and downlink.
NOTE 2: Combinations f2) and f3) are used without EPC in multislot configurations as defined in subclause 8.3.5.
NOTE 3: Combinations f5) and f6) are used with EPC in multislot configurations as defined in subclause 8.3.5.
The following definitions are used in the list of half rate combinations below.
|
Combination designation |
Channel combination |
|
SUB_FA |
DCH/H(s) + SACCH/TH |
|
SUB_FE |
DCH/H(s) + SACCH/TPH + EPCCH/H |
The following are the permitted ways in which channels can be combined onto one basic physical channel for two MSs on two DBPSCH/H:
g1) SUB_FA + SUB_FA
g2) SUB_FA + SUB_FE
g3) SUB_FE + SUB_FE
g4) SUB_TA + SUB_FA
g5) SUB_TA + SUB_FE
g6) SUB_TE + SUB_FA
g7) SUB_TE + SUB_FE
g8) SUB_OTA + SUB_FA
g9) SUB_OTA + SUB_FE
g10) SUB_OTE + SUB_FA
g11) SUB_OTE + SUB_FE
8.3.5 Multislot configurations
8.3.5.1 Multislot configurations for DBPSCHs assigned
A multislot configuration consists of multiple DBPSCH/F assigned to the same MS. The multislot configuration occupies up to 8 basic physical channels, with different timeslots numbers (TN) but with the same frequency parameters (ARFCN or MA, MAIO and HSN) and the same training sequence (TSC).
Two types of multislot configurations exist, symmetric and asymmetric. The symmetric case consists of only bi-directional channels. The asymmetric case consists of both bi-directional and unidirectional downlink channels.
The occupied physical channels shall consist of the following channel combinations as defined in subclause 8.3.4.
x channels of type f2) +
y channels of type f3)
When in EPC mode (see 3GPP TS 45.008) the occupied physical channels shall consist of the following channel combinations as defined in subclause 8.3.4.
x channels of type f5) +
y channels of type f6)
where 1<= x <= 8, y = 0 for symmetric multislot configuration
1<= x <= 7, 1 <= y <= 7, x+y <= 8 for asymmetric multislot configuration
The assignment of channels to a Multislot Configuration must always consider the multislot capability of the MS, as defined by the multislot class described in annex B.
8.3.5.2 Multislot configurations for dual transfer mode in Iu mode
The multislot configuration for dual transfer mode in Iu mode is the same as in 6.4.2.7. The only difference is that FLO is used on the assigned DBPSCHs.
Annex A (normative):
Phase 2 mobiles in a Phase 1 infrastructure