top button
Flag Notify
    Connect to us
      Facebook Login
      Site Registration Why to Join

Facebook Login
Site Registration

LTE: Difference between synchronous and asynchronous harq ?

+7 votes
856 views
LTE: Difference between synchronous and asynchronous harq ?
posted Dec 6, 2013 by Vimal Kumar Mishra

Share this question
Facebook Share Button Twitter Share Button Google+ Share Button LinkedIn Share Button Multiple Social Share Button

1 Answer

+1 vote

Synchronous HARQ (used in UPLINK):
1. Re-transmissions are scheduled at fixed time intervals
2. Generates lower over-head as it doesn't need to include HARQ process Id in the outgoing data
3. Always works in cycle even if no resources are allocated during a specific sub frame; which means that the 1st process will repeat itself after every 8 ms.

Asynchronous HARQ (used in DOWNLINK):
1. eNB can use any of the HARQ process (out of 1-8 SAW process) in the DL
2. eNB provides instructions to the UE regarding which HARQ process to use during each sub-frame for which resources are allocated. (The HARQ process identity is included within the PDCCH transmission)
3. Asynchronous HARQ increases signalling overhead because it includes the HARQ process Identity within the DCI.
4. Asynchronous HARQ increases flexibility because re-transmissions doesn't have to be scheduled during every sub-frame.

answer Dec 6, 2013 by Kumar Mitrasen
Contact Us
+91 9880187415
sales@queryhome.net
support@queryhome.net
#280, 3rd floor, 5th Main
6th Sector, HSR Layout
Bangalore-560102
Karnataka INDIA.
QUERY HOME
...