[Discuss-gnuradio] 802.15.4 Frame sync confusion

[sumit kumar]

Hi, 

If my understanding is correct, most of the 802.15.4 receiver implementations perform frame synchronization i.e. find the start of the frame using the preambles which are nothing but 8 zeros(each of which is further converted to 32 bit chip). 

This is done after the OQPSK symbols (complex samples) are already decoded to bits. Same does the gr-ieee 802.15.4

I was wondering why 802.15.4 does not do frame sync using the complex samples itself like WiFi do using STS ? 

I mean, it already has a pattern of 8 repeated zeros and hence a repeated sequence of complex samples in the beginning of every frame. 

What I am missing here ? 

Regards

Sumit