What is ARQ in LTE?
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 difference between HARQ and ARQ in LTE?
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.
What is the difference between ARQ and FEC?
The difference between ARQ and FEC is that ARQ wastes the bandwidth by using retransmission, whereas FEC requires additional redundancy in the transmitted information and incurs significant processing complexity in performing the error correction.
How many HARQ process in LTE?
8
The figure below shows the timing diagram of LTE FDD uplink HARQ process between eNB and UE (X-Series). There are 8 uplink HARQ processes running on both UE and eNB with 4 processes delay. HARQ process length is same as a subframe (1 ms). When UE sends data to eNB, eNB decodes data and checks CRC.
What do you mean by hybrid ARQ?
Hybrid automatic repeat request
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 loop?
3GPP specifies retransmission periods and response times at the radio level between the UE and the network as the HARQ loop, which includes: the air-interface transmission time, completion times for RF-L1/PHY-MAC functions, and RF-L1/PHY-MAC functions in the UE.
What is forward error correction in networking?
Forward error correction (FEC) is a method of obtaining error control in data transmission in which the source (transmitter) sends redundant data and the destination (receiver) recognizes only the portion of the data that contains no apparent errors. In the simplest form of FEC, each character is sent twice.
What is error detection codes in digital electronics?
Error-detecting codes are a sequence of numbers generated by specific procedures for detecting errors in data that has been transmitted over computer networks. The corrupted bits leads to spurious data being received by the receiver and are called errors.
What is HARQ RTT timer in LTE?
Simple way to understand: the HARQ Round Trip Time (RTT) timer is defined for UE to sleep during HARQ RTT. When decoding DL TB for one HARQ fails, UE can next retransmission TB after at least HARQ RTT sub frames. At HARQ RTT timer expiry, UE resumes PDCCH reception.
What is RV LTE?
Uplink transmission in LTE uses synchronous HARQ. This means that eNodeB knows exactly which RV (Redundant Version) and HARQ process the UE will transmit. The RV specifies which set of ED, FEC and Data bits are being sent.
What is the purpose of hybrid of FEC and ARQ?
The FEC code is chosen to correct an expected subset of all errors that may occur, while the ARQ method is used as a fall-back to correct errors that are uncorrectable using only the redundancy sent in the initial transmission.
What is split in 5G?
In Release 15, 3GPP, defined a new, flexible architecture for the 5G RAN, where the base station or gNodeB (gNB) is split into three logical nodes: the Central Unit, (CU), the Distributed Unit, (DU) and the Radio Unit, (RU), each capable of hosting different functions of the 5G NR stack.
What is ARQ (automatic repeat request)?
This is a physical layer functionality in LTE. ARQ: Automatic Repeat Request. It means, if the sender doesn’t receive ACK from the receiver before timeout, then the receiver will discard the packet and sender will retransmit the packet.
What is a hybrid ARQ code?
Jump to navigation Jump to search. Hybrid automatic repeat request (hybrid ARQ or HARQ) is a combination of high-rate forward error-correcting coding and 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 the difference between ARQ and HARQ in LTE?
HARQ stands for Hybrid Automatic Repeat Request (HARQ). This is a physical layer functionality in LTE. ARQ: Automatic Repeat Request. It means, if the sender doesn’t receive ACK from the receiver before timeout, then the receiver will discard the packet and sender will retransmit the packet.
What is the difference between synchronous and asynchronous HARQ in LTE?
Synchronous HARQ – used in LTE Uplink transmission. Asynchronous HARQ – used in LTE Downlink transmission. Synchronous HARQ: In this, receiver has knowledge of the packet which is about to come in this subframe i.e. eNodeB knows exactly which HARQ no. and RV UE is going to send. eNodeB determines them from transmission time.