DSSS & LoRa Modulation

I am currently reading the Semtech document AN1200.2
( https://www.semtech.com/uploads/documents/an1200.22.pdf ) . They introduce the LoRa spread spectrum modulation by explaining Direct Sequency Spread Spectrum (DSSS) first. In the diagram (page 7 figure 1) they Combine their Information Signal with the chipping sequency via XNOR. However, in all other articles it says DSSS uses a XOR to Combine Information Signal and chipping sequency. Can someone explain to me why they didnt choose XOR in the document?
Also, I don´t really understand why they Chose to explain DSSS. It seems to me like DSSS and LoRa spread spectrum are totally different, or do they have anything in common that makes the understanding of CSSS necessary to understand LoRa? Any explaination or link is a great help, I am also grateful for all links and documents regarding the theoretics of LoRa and LoRaWAN as I am currently writing my Bachelor Thesis about this Topic. Unfortunately it is quite difficult to find documents that go deeper into the matter and don´t just scratch at the surface…
Thank you so much!

you could ask this VERY specific question at the manufacturers forum
http://semtech.force.com/lora/LC_Answers_Questions#!/feedtype=RECENT&criteria=BESTANSWERS

LoRaWAN academic research publications

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