My friend: Hi Soumya, I have a question for you.
Me: Please, go ahead.
My friend: I am wondering what is meant by self-contained slot in 5G?
Me: Actually, it is a new concept in 5G to allow for lower latency as you know that URLLC is one of the basic use cases in 5G and so self-contained slot is used to enhance this concept for TDD frames.
My friend: But, how does it work?
Me: It is done by allowing both the DL transmission and UL feedback to be in the same slot which will reduce the delay and this is implemented by allowing the HARQ ACK sent from the UE in the last one or two symbols of a slot (using short PUCCH) to be in the same slot where the UE will receive its DL packets, so the symbols of the slot will contain both the DL data and also the UL feedback which is the HARQ ACK (check the attached photo). This will reduce the delay from the end of the DL transmission until the reception of the ACK from the UE to be in the order of an OFDM symbol, corresponding to a few tens of microseconds depending
on the numerology used. This can be compared to almost 3ms in LTE.
My friend: Thanks a lot. You make it very simple.
Please press the like and share buttons to spread this info for everyone.
Me: Please, go ahead.
My friend: I am wondering what is meant by self-contained slot in 5G?
Me: Actually, it is a new concept in 5G to allow for lower latency as you know that URLLC is one of the basic use cases in 5G and so self-contained slot is used to enhance this concept for TDD frames.
My friend: But, how does it work?
Me: It is done by allowing both the DL transmission and UL feedback to be in the same slot which will reduce the delay and this is implemented by allowing the HARQ ACK sent from the UE in the last one or two symbols of a slot (using short PUCCH) to be in the same slot where the UE will receive its DL packets, so the symbols of the slot will contain both the DL data and also the UL feedback which is the HARQ ACK (check the attached photo). This will reduce the delay from the end of the DL transmission until the reception of the ACK from the UE to be in the order of an OFDM symbol, corresponding to a few tens of microseconds depending
on the numerology used. This can be compared to almost 3ms in LTE.
My friend: Thanks a lot. You make it very simple.
Please press the like and share buttons to spread this info for everyone.
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