Why code rate is fixed to 1/3 in LTE?

Question

IN LTE RV version sequence in DL is 0 ,2,3 1 but in UL its 0,2,3,1 why so

Answer 1

Because In lte we are using turbo encoding which encodes input and generate 2 more secondary sequence which will use for correct data at receiver side.so, instead of sending 1 sequence we are sending 3 sequence(1 input , 2 secondary sequence).
that's why code rate is fixed 1/3.

Comments

Thank you can you please explain what is turbo encoding? I'm new to LTE.

Answer 2

Turbo encoding we are using in physical layer.it is one type of coding algorithm for correct data at receiver side.
Before sending data we will do channel coding.
refer this http://www.sharetechnote.com/html/BasicProcedure_LTE_ChannelCoding_DL_SCH.html.