## 5.1a.31 Packet data block type 42 (DBS-12)

3GPP45.003GSM/EDGE Channel codingRelease 17TS

#### 5.1a.31.1 Block constitution

If the message delivered to the encoder does not include a PAN, it has a fixed size of 2441 information bits {d(0),d(1),…,d(2440)}. If the message delivered to the encoder includes a PAN, it has a fixed size of 2466 information bits {d(0),d(1),…,d(2465).

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,…,64

i1(k-65) = d(k) for k = 65,…,658

i2(k-659) = d(k) for k = 659,…,1252

i3(k-1253) = d(k) for k = 1253,…,1846

i4(k-1847) = d(k) for k = 1847,…,2440

And if a PAN is included:

pn(k-2441) = d(k) for k = 2441,…,2465

#### 5.1a.31.2 USF coding

The USF coding is the same as for DBS-10 as specified in subclause 5.1a.29.2.

#### 5.1a.31.3 Header coding

The header coding is the same as for DBS-11 as specified in subclause 5.1a.30.3.

#### 5.1a.31.4 Data coding

Each data part, {i1(0),…,i1(593)}, {i2(0),…,i2(593)}, {i3(0),…,i3(593)} and {i4(0),…,i4(593)}, is coded as defined in subclause 5.1a.1.3, with N=594, resulting in four coded blocks of 1830 bits, {C1(0),…,C1(1829)}, {C2(0),…,C2(1829)}, {C3(0),…,C3(1829)} and {C4(0),…,C4(1829)}.

Each coded block is punctured depending on the value of the CPS field as defined in 3GPP TS 44.060. Three puncturing schemes named P1, P2 or P3 are applied.

The parameter values used for rate matching are: *swap*=0, =610,=620 and =606.

P1 puncturing is generated according to 5.1a.1.3.5 using the parameters above if PAN is not included. If PAN is included in P1, then for generation of P1, N = 606 is used.

NOTE: When PAN is included, P1 calculated as above results in transmission of all systematic bits.

P2 (Type 2) puncturing is generated according to 5.1a.1.3.5.

P3 puncturing is generated according to 5.1a.1.3.5.

NOTE: P2 and P3 are always generated using N = 610 irrespective of whether or not P1 is with or without PAN.

If a PAN is not included, the result is four blocks of 620 bits, {c1(0),…,c1(619)}, {c2(0),…,c2(619)}, {c3(0),…,c3(619)} and {c4(0)…,c4(619)}.

If a PAN is included, the result is four blocks of 606 bits, {c1(0),…,c1(605)}, {c2(0),…,c2(605)}, {c3(0),…,c3(605)} and {c4(0),…,c4(605)}.

NOTE: C1 and c1 correspond to i1, C2 and c2 to i2, C3 and c3 to i3, and C4 and c4 to i4.

#### 5.1a.31.5 PAN coding

The PAN {pn(0),…,pn(24)}, if included, is coded as defined in subclause 5.1a.1.4, resulting in a block of 90 bits, {C(0),…,C(89)}.

The code is punctured in such a way that the following coded bits:

{C(15*k) , C(15*k+2), C(15*k+4), C(15*k+7), C(15*k+10), C(15*k+13) for k = 0,1,…5} are not transmitted; except C(15), C(45) which are transmitted.

This results in a block of 56 bits, {ac(0),…,ac(55)}.

#### 5.1a.31.6 Interleaving

a) Header

The header interleaving is the same as for DBS-11 as specified in subclause 5.1a.30.6.

b) Data and PAN

If a PAN is not included, the following definitions apply:

dc1(k) = c1(k) for k = 0,…,619

dc2(k) = c2(k) for k = 0,…,619

dc3(k) = c3(k) for k = 0,…,619

dc4(k) = c4(k) for k = 0,…,619

If a PAN is included, the following definitions apply:

dc1(k) = ac(4k) for k = 0,…,13

dc1(k) = c1(k-14) for k = 14,…,619

dc2(k) = ac(4k+1) for k = 0,…,13

dc2(k) = c2(k-14) for k = 14,…,619

dc3(k) = ac(4k+2) for k = 0,…,13

dc3(k) = c3(k-14) for k = 14,…,619

dc4(k) = ac(4k+3) for k = 0,…,13

dc4(k) = c4(k-14) for k = 14,…,619

The four blocks {dc1(0),…,dc1(619)}, {dc2(0),…,dc2(619)}, {dc3(0),…,dc3(619)} and {dc4(0),…,dc4(619)} are separately interleaved as defined in subclause 5.1a.2.2, with N_{C}=620 and a=141, resulting in the four blocks {di1(0),…,di1(619)}, {di2(0),…,di2(619)}, {di3(0),…,di3(619)} and {di4(0),…,di4(619)}, where di1 corresponds to dc1, di2 to dc2, di3 to dc3 and di4 to dc4.

The blocks are put together as one entity as described by the following rule:

di(k) = di1(k) for k = 0,…,619

di(k) = di2(k-620) for k = 620,…,1239

di(k) = di3(k-1240) for k = 1240,…,1859

di(k) = di4(k-1860) for k = 1860,…,2479

#### 5.1a.31.7 Mapping on a burst

a) Straightforward mapping

The mapping is the same as for DBS-11 as specified in subclause 5.1a.30.7 a).

b) Bit swapping

The bit swapping is the same as for DBS-11 as specified in subclause 5.1a.30.7.b).

c) PAN bit swapping

In case a PAN is included in the radio block, the following additional bits are swapped after the bit swapping in b):

For B = 0, 1, 2 and 3

Swap e(B,29) with e(B,158)

Swap e(B,141) with e(B,80)

Swap e(B,226) with e(B,110)

Swap e(B,282) with e(B,98)

Swap e(B,381) with e(B,480)

Swap e(B,437) with e(B,433)

Swap e(B,522) with e(B,503)

Swap e(B,634) with e(B,410)