How to calcuate IEEE 802.11 CRC-32 FCS?

Question

This is from IEEE Std 802.11-2012 Clause 8.2.4.8 FCS field:

I cannot understand the last two paragraphs:

1. What's the meaning by "the initial remainder of the division is preset to all ones", and why we need to do that?

2. What's the meaning by "... the serial incoming bits of the calculation fields and FCS..." ?

Answer 1

1. Initializing the CRC to all ones avoids the problem of a string of zeros of any length giving a zero CRC.

2. Read Ross Williams CRC tutorial.