## 4.2.10 Physical channel segmentation

25.2123GPPMultiplexing and channel coding (FDD)Release 17TS

When more than one PhCH is used, physical channel segmentation divides the bits among the different PhCHs. The bits input to the physical channel segmentation are denoted by , where *X* is the number of bits input to the physical channel segmentation block. The number of PhCHs is denoted by *P.*

The bits after physical channel segmentation are denoted , where *p* is PhCH number and *U* is the number of bits in one radio frame for each PhCH, i.e. . The relation between *x _{k}* and

*u*is given below.

_{p,k}For all modes, some bits of the input flow are mapped to each code until the number of bits on the code is *U*. All bits of the input flow are taken to be mapped to the codes.

Bits on first PhCH after physical channel segmentation:

*u _{1, k }= x_{k} k = *1, 2 , …,

*U*

Bits on second PhCH after physical channel segmentation:

*u _{2, k }= x_{k+U }*

*k =*1, 2 , …,

*U*

…

Bits on the *P ^{th}* PhCH after physical channel segmentation:

*u _{P,k }= x_{ k+(P-1)}*

_{}

_{U}*k =*1, 2 , …,

*U*

#### 4.2.10.1 Relation between input and output of the physical segmentation block in uplink

The bits input to the physical segmentation are denoted by . Hence, *x _{k} = s_{k}* and

*Y = S*.

#### 4.2.10.2 Relation between input and output of the physical segmentation block in downlink

The bits input to the physical segmentation are denoted by . Hence, *x _{k} = w_{k}* and

*Y = PU*.