Sunday, January 24, 2016

Using LDPC in wifi

Wifi use forward error correction, in 802.11n(HT) and 802.11ac(VHT) LDPC codes were introduced as an option. The AP advertise whether it supports LDPC by setting the LDPC bit in HT capabilities information element,

pkt capture : https://drive.google.com/file/d/0B3ctVg8ubiwUSXo1NnlnVjVuSG8/view?usp=sharing


 If the client is able to use LDPC code it will set the LDPC bit in association request



The AP will respond with LDPC bit set to 1 in association response.




Once this is done the AP and the client can send pkts coded with LDPC to each other, whether a pkt is coded with LDPC or not is indicated in 802.11 radio info,


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