can anyone Explain about HARQ and ARQ in LTE?

Question

As per my knowledge HARQ will do Retransmission and stored data in Buffer.now My doubt is who will clear that buffer Data in LTE?

Comments

A very good explanation of HARQ and ARQ
http://www.telecomhall.com/what-is-retransmission-arq-and-harq.aspx

Can you bit bit clear about the second part.

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Thanks For your response.
HARQ Buffer Data after re transmission who will Clean that Buffer either RLC or MAC?

Answer 1

HARQ mechanism is used for forward error correction. MAC layer start HARQ process and control by PHY layer. whereas ARQ has significance at RLC layer only. In case of NACK received for the transmitted data, PHY layers doesn't retransmit same data. PHY send some different data(good enough) so that receiver take this re-transmitted data with the earlier received corrupted data and try to decode and then send either NACK or ACK to receiver.

In ARQ mechanism, same data is used for re-transmission. In LTE, for the better resource optimization, HARQ has been introduced.

Answer 2

MAC layer manages these HARQ processes. and Data is removed when:
a. ACK is received
b. Max number of re-transmission has reached

This link is also useful for HARQ understanding http://lteinwireless.blogspot.in/2012/03/harq-in-lte.html