# How can I estimate Bhattacharyya parameter for BSC channel, used for Polar codes

In polar codes, the frozen bits in each message are determined through the worst channel, where the relevant parameter is the Bhattacharyya .

How can I estimate Bhattacharyya parameter for BSC channel?

• There is no need to estimate. You can compute it exactly using the formula. See for example formula (14) on page 5 of this paper. – Yuval Filmus Jun 27 '17 at 20:04
• For large block the calculation is o(n^2) , is there more efficient way? – Rorden Jahne Jun 28 '17 at 17:34
• Perhaps it would be better if you explained what exactly you want to compute, including a complete formula. – Yuval Filmus Jun 28 '17 at 17:36