In LTE, the uplink physical channel (PUCCH) carrying uplink control information (UCI) can include channel state information (CSI) reports, Hybrid Automatic Retransmission reQuest (HARQ) ACKnowledgment/Negative ACKnowledgment (ACK/NACK) and uplink scheduling requests (SR).

What is channel selection LTE?

One method for HARQ feedback with multiple ACK/NACK bits is channel selection, wherein ACK/NACK information is encoded by the joint selection of a channel (transmit sequence) and a QPSK symbol. …

Which channel is used for ACK NACK feedback in uplink in 5G?

As a fundamental building component to enable NR system, physical Uplink Control Channel (PUCCH) is mainly utilized to convey Uplink Control Information (UCI), including [4]: HARQ-ACK (Hybrid Automated Repeat Request- Acknowledgement) feedback in response to downlink data transmission.

Which channel is used for uplink scheduling?

LTE provides a random-access (transport) channel (RACH) in the UL, mainly utilized for initial radio-link establishment, handover, and synchronization. RACH may also carry UL scheduling requests if no dedicated physical uplink control channel (PUCCH) has been assigned.

What is HARQ feedback?

The HARQ feedback channels are used to carry ACK/NACK information corresponding to downlink transmissions. The HARQ feedback channels start at predetermined time offsets relative to the corresponding DL transmissions and are frequency-division multiplexed with other control and data channels over an uplink subframe.

What is HARQ in LTE?

Hybrid automatic repeat request (hybrid ARQ or HARQ) is a combination of high-rate forward error correction (FEC) and automatic repeat request (ARQ) error-control. In standard ARQ, redundant bits are added to data to be transmitted using an error-detecting (ED) code such as a cyclic redundancy check (CRC).

What is HARQ process?

HARQ process relies upon receiving ACK for the packets. If the sender sends a packet and then waits for the ACK to send another packet, it is called a SAW(stop and wait) process. It increases the round trip time ( sender and receiver processing time + propagation delays).

What is Pucch and UCI or it’s formats?

PUCCH (Physical Uplink Control Channel) carries a set of information called “UCI(Uplink Control Information)”. (This is similar to PDCCH which carries DCI (Downlink control information)”.

What is HARQ process in NR?

In 5G NR, 3GPP specification has defined HARQ Codebook to provide the feedback to base station for Downlink data transmission i.e., PDSCH Data. Multiple HARQ process (upto 16) is supported per UE and there has to be separate feedback for each HARQ Process.

Which LTE protocol is responsible for HARQ and scheduling?

Finally, the Medium Access Control (MAC) sublayer provides Hybrid-ARQ (HARQ) and is responsible for the functionality that is required for medium access, such as scheduling operation and random access.

What is LTE HARQ?

HARQ stands for Hybrid Automatic Repeat Request. HARQ = ARQ + FEC (Forward Error Correction)/Soft Combining. ARQ refers to Automatic Repeat Request i.e. if sender doesn’t receive Acknowledgement (ACK) before timeout, the receiver discards the bad packet and sender shall re-transmits the packet.

What is the formula for HARQ process ID in LTE?

In LTE, there is no specific formula is defined in the 3GPP specification, but following can be one of the simplest rule in LTE case. Does the reciever (eNodeB in LTE case) need to know exact HARQ process ID?

What is the mode of HARQ process in FDD?

A little bit different mode of HARQ process is used depending on whether it is for FDD or TDD and whether it is for Uplink and Downlink. But I will talk only about FDD case. In FDD, we are using 8 HARQ process. a) it can use the 8 HARQ processes in any order ( Asynchronous Process ).

What is PUCCH format used for in LTE Advanced?

PUCCH format specially designed for LTE Advanced/Carrier Aggregation. PUCCH format1b/PUCCH Format3 LTE Advanced – PUCCH Home : When you are thinking of LTE Advanced, the first feature you would think would be `Carrier Aggregation`.

What is HARQ?

The “H” in HARQ means “Hybrid” which implies that HARQ is a combination of “Something” and “ARQ”. Then what would be the “Something”? The “Something” is FEC (forward error correction). FEC is also not LTE specific technology and a kind of generic error correction mechanism.