# RF Wireless World

## LTE PDCCH Calculator | LTE CCE Index Calculator

This page mentions LTE PDCCH Calculator. It calculates CCE Index based on Aggregation level or PDCCH formats. The formula used in LTE PDCCH calculator or CCE Index calculation is also mentioned.

CCE stands for Control Channel Elements. 1 CCE occupies 36 REs (Resource Elements) or 72 bits as it is QPSK modulated. PDCCH format 0 refers to aggregation level of 1, PDCCH format 1 refers to aggregation level of 2, PDCCH format 2 refers to aggregation level of 4 and PDCCH format 3 refers to aggregation level of 8.

➨If CCE Index is 0 and aggregation level is 4 means, it occupies CCE positions from 0 to 3.
➨If CCE index is 4 and aggregation level is 4 means, it occupies CCE positions from 4 to 7.
➨If CCE index is 0 and aggregation level is 8 means, it occupies CCE positions from 0 to 7.
and so on...

Aggregation Level (Enter: 1/2/4/8):

Number of CCEs (N_CCE) :

Subframe Number, k (Enter: Range 0 to 9 ):

LTE CCE Index for PDCCH channel(Output#1):

LTE PDCCH CALCULATOR EXAMPLE for CCE Index Calculation:
Input : Aggregation level (L) = 1, N_CCE = 100 , Subframe (k ) = 1,
Outputs : CCE Index = 49

Following table mentions all possible inputs and respective CCE index as output. It also mentions intermediate outputs e.g. yk and y(k-1).

K(subframe number) Y(k-1) Y(k) N_CCE CCE Index
0 100 50480 100 81
1 50480 53948 100 49
2 53948 21988 100 89
3 21988 10682 100 83
4 10682 31347 100 48
5 31347 42656 100 57
6 42656 10398 100 99
7 10398 58380 100 81
8 58380 44111 100 12
9 44111 23975 100 76

### LTE CCE Index Calculation formula used in LTE PDCCH Calculator

Following equations/formula are used in this LTE PDCCH Calculator for CCE Index calculation. Where,
L = Aggregation levels viz. 1/2/4/8
NCCE = Number of CCEs available for PDCCH channel type
m = range from 0 to (Number of PDCCH candidates-1)
i = range from 0 to (L-1)
Yk = { A * (Yk-1) } mod D
k =Subframe number
A = constant value of 39827
D = constant value of 65537

For k = 0, (Yk-1) = RNTI value of UE = Assume as 100 say