Wimax(802.16d) subchannelization doubt???

[rag_perfect]

Hi frnds...

i have one doubt regarding subchannelization. As per standard, Read-soloman(RS) coding/decoding is not employed whenever Subchannelizetion occurs....

Can anybody plz explain why it is so????

 

[achandra]

Just look at the dimensions of the Reed-Solomon encoding scheme that is directed by the standard. U will see that when sub-channelization is applied the data becomes too small to use RS on a sub-channel basis...

 

[rag_perfect]

thankx 4 ur reply... but my doubt is :why data becomes small in only subchannelization case... and moreover will it happen every time as soon as subchannelization comes into picture???

plz help.....

 

[achandra]

ya the MAC frame that comes from MAC layer is mapped onto the subchannels allocated according to the modulation scheme applied. So for a particular modulation scheme if the no. of subchannels is reduced it means that the no. of bits mapped on to those sub-channels is reduced. Yes it happens every time subchannelization comes into picture.

 

[rag_perfect]

thankx dude...
u have really a good knowledge of MAC....
i hope u will help me again whenever i will be in need.....