Hi Expert
Can you please explain what are the major difference between harq and tti bundling?
Hi Expert
Can you please explain what are the major difference between harq and tti bundling?
Harq results in a single Retx after each NACK or DTX
Tti bundling a combination of TX and 3 retx in 4 consecutive TTIs
TTI bundling:
https://www.sharetechnote.com/html/Handbook_LTE_TTIBundling.html
TTI Bundling
In normal case, when network send a grant (DCI 0), UE transmit PUSCH at only one specific subframe (4 ms after the DCI 0 reception). TTI Bundling is a method in which UE transmit a PUSCH in multiple subframes in a row (4 subframes according to current specification). In other words, UE transmit a PUSCH in a ‘BUNDLED TTI’.
HARQ bundling:
ETSI TS 136 213 V10.6.0 (2012-07) page 69:
if two transport blocks are received on a serving cell, the HARQ-ACK bit for the serving cell is generated by spatially bundling the HARQ-ACK bits corresponding to the transport blocks;
TTI bundling enables the data to be transmitted in consecutive TTIs as a single resource during the scheduling process. It makes use of HARQ gains. The HARQ is a technique when the receiver gets a new data with some errors then it tries to make correction if the error is minor, but if the error is not minor then it sends re-transmission request to the sender. … The ARQ mechanism takes care of residual errors which passed from HARQ