The following figure shows the difference in processing procedure between BCC encoding and LDPC encoding. First, compared with BCC, no tail bits and padding bits are added for LDPC. Next, a single FEC encoder is always used in LDPC coding, while more than 1 FEC encoders can be used in BCC coding. Last, the Encoder Parser and Interleavers are not used in LDPC.
Even compared with the LDPC used in WLAN 802.11ac, there are some differences. For WLAN 802.11ac, the padding bits are appended after PSDU but not for WLAN 802.11n. Also an LDPC Tone Mapper is applied after the Constellation Mapper for WLAN 802.11ac but not for WLAN 802.11n.
When the encoder is disabled, the type of encoder still needs to be known since it determines which processing procedure to follow. The following figure shows the process in Basic mode.
