5.1a.24 Packet data block type 35 (DBS-5)

3GPP45.003GSM/EDGE Channel codingRelease 17TS

5.1a.24.1 Block constitution

If the message delivered to the encoder does not include a PAN, it has a fixed size of 480 information bits {d(0),d(1),…,d(479)}. If the message delivered to the encoder includes a PAN, it has a fixed size of 505 information bits {d(0),d(1),…,d(504).

NOTE: The presence of the PAN is indicated by the PANI field in the header (see 3GPP TS 44.060).

The message is separated into the following parts:

u(k) = d(k) for k = 0,…,2

h(k-3) = d(k) for k = 3,…,29

i(k-30) = d(k) for k = 30,…,479

And if a PAN is included:

pn(k-480) = d(k) for k = 480,…,504

5.1a.24.2 USF coding

5.1a.24.2.1 BTTI configuration

The USF bits {u(0),u(1),u(2)} are block coded into 32 bits u’(0),u’(1),…,u’(31) according to the following table:

u(0),u(1),u(2)	u’(0),u’(1),…,u’(31)
	burst 0	burst 1	burst 2	burst 3
000	0 0 1 1 0 0 1 1	0 0 1 1 0 0 1 1	0 0 1 1 0 0 1 1	0 0 1 1 0 0 1 1
001	1 1 0 0 1 1 0 0	0 0 1 1 0 0 1 1	0 0 1 1 1 1 0 0	1 1 0 0 0 0 1 1
010	1 1 0 0 0 0 1 1	1 1 0 0 0 0 1 1	1 1 0 0 0 0 1 1	1 1 0 0 0 0 1 1
011	0 0 1 1 1 1 0 0	1 1 0 0 0 0 1 1	1 1 0 0 1 1 0 0	0 0 1 1 0 0 1 1
100	1 1 0 0 0 0 1 1	0 0 1 1 1 1 0 0	0 0 1 1 0 0 1 1	1 1 0 0 1 1 0 0
101	0 0 1 1 1 1 0 0	0 0 1 1 1 1 0 0	0 0 1 1 1 1 0 0	0 0 1 1 1 1 0 0
110	0 0 1 1 0 0 1 1	1 1 0 0 1 1 0 0	1 1 0 0 0 0 1 1	0 0 1 1 1 1 0 0
111	1 1 0 0 1 1 0 0	1 1 0 0 1 1 0 0	1 1 0 0 1 1 0 0	1 1 0 0 1 1 0 0

5.1a.24.2.2 RTTI configurations

If the USF is sent in RTTI USF mode (see 3GPP TS 45.002) when data blocks are transmitted in RTTI configuration, then the USF bits {u(0),u(1),u(2)} are block coded into 32 bits u’(0),u’(1),…,u’(31) as described in subclause 5.1a.24.2.1.

If the USF is sent in BTTI USF mode (see 3GPP TS 45.002) when data blocks are transmitted in RTTI configuration, then the three bits of the USF to be sent on the lower numbered PDCH of a corresponding downlink PDCH-pair are block coded into 32 bits u_L(0),u_L(1),…,u_L(31) as described in subclause 5.1a.24.2.1; the three bits of the USF to be sent on the higher numbered PDCH of a corresponding downlink PDCH-pair are block coded into 32 bits u_H(0),u_H(1),…,u_H(31) as described in subclause 5.1a.24.2.1.

NOTE: If BTTI USF mode is used when sending data blocks in RTTI configuration, then u(0),u(1),u(2) need not contain a USF; in this case, they are ignored by the encoder. How the USFs are delivered to the encoder in this case is implementation dependent.

If the data block is sent in the first 10ms of a 20ms block period, then:

u’(j)=u_L(j), j=0…7

u’(j)=u_H(j-8), j=8…15

u’(j)=u_L(j-8), j=16…23

u’(j)=u_H(j-16) j=24…31

If the data block is sent in the second 10ms of a 20ms block period, then:

u’(j)=u_L(j+16), j=0…7

u’(j)=u_H(j+8), j=8…15

u’(j)=u_L(j+8), j=16…23

u’(j)=u_H(j) j=24…31

NOTE: In case mixed modulation USF is used (see subclause 5.1), the USF bits sent during the other half of the 20 ms block period may be sent with a different modulation. In this case, the half of u_L and u_H not sent in the present data block will be discarded.

5.1a.24.3 Header coding

The header {h(0),…,h(26)} is coded as defined in subclause 5.1a.1.1, with N=27, resulting in a block of 105 bits, {C(0),…,C(104)}.

Some bits of the code are repeated in the following way:

hc(k) = C(k) for k = 0, 1, … 104 and

hc(105) = C(0), hc(106) = C(33), hc(107) = C(70)

This results in a block of 108 bits, {hc(0),…,hc(107)}.

5.1a.24.4 Data coding

The data part, {i(0),…,i(449)}, is coded as defined in subclause 5.1a.1.3, with N=450, resulting in a coded block of 1398 bits, {C(0),…,C(1397)}.

The coded block is punctured depending on the value of the CPS field as defined in 3GPP TS 44.060. Two puncturing schemes named P1 or P2 are applied.

The parameter values used for rate matching are: swap=0.05, =466,=956 and =876.

P1 puncturing is generated according to 5.1a.1.3.5

P2 (Type 1) puncturing is generated according to 5.1a.1.3.5.

If a PAN is not included, the result is a block of 956 bits, {c(0),…,c(955)}.

If a PAN is included, the result is a block of 876 bits, {c(0),…,c(875)}.

5.1a.24.5 PAN coding

The PAN coding is the same as for UBS-5 as specified in subclause 5.1a.8.4.

5.1a.24.6 Interleaving

a) Header

The header, {hc(0),…,hc(107)}, is interleaved as defined in subclause 5.1a.2.1, with N_C=108 and a=10, resulting in a block of 108 bits, {hi(0),…,hi(107)}.

b) Data and PAN

If a PAN is not included, the following rule applies:

dc(k) = c(k) for k = 0,…,955

If a PAN is included, data and PAN are put together as one entity as described by the following rule:

dc(k) = ac(k) for k = 0,…,79

dc(k) =c(k-80) for k = 80,..,955

The block {dc(0),…,dc(955)} is interleaved as defined in subclause 5.1a.2.1, with N_C=956 and a=173, resulting in a block of 956 bits, {di(0),…,di(955)}.

5.1a.24.7 Mapping on a burst

The mapping is given by the rule:

For B=0,1,2,3, let

e(B,j) = di(239B+j) for j = 0,…,119

e(B,j) = hi(27B+j-120) for j = 120,…,135

e(B,j) = q(2B+j-136) for j = 136,137

e(B,j) = u’(8B+j-138) for j = 138,…,145

e(B,j) = hi(27B+j-130) for j = 146,…,156

e(B,j) = di(239B+j-37) for j = 157,…,275

where

q(0),q(1),…,q(7) = 0,0,0,0,0,0,0,0 identifies the coding scheme DBS-5 or DBS-6.

In RTTI configuration, the bursts with B = 0,2 shall be mapped on the PDCH having the lower timeslot number, whereas the bursts with B = 1,3 shall be mapped on the PDCH having the higher timeslot number, see 3GPP TS 45.002.