What is incremental redundancy?
Incremental redundancy (IR) transmits increments of redundant bits after errors are observed. IR adaptively changes an effective data rate based on the results of actual transmissions.
What is redundancy version in Harq?
In Type #2 HARQ, redundancy is added on each re-transmission and receiver needs to decode each of them to obtain packet. In Type 3 HARQ, each re-transmission is sufficient to decode data and re-transmission is made only if the channel conditions are not good and data was not decoded correctly.
What is ARQ and FEC transmission?
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 incremental redundancy in LTE?
LTE utilizes incremental-redundancy HARQ with a 1/3 turbo encoder used for FEC. The transport block CRC is used to detect errors. The receiver only receives different punctured versions of the same turbo-encoded data; each of these retransmissions is self-decodable.
What is redundancy in LTE?
The redundancy version tells the UE, about amount of redundancy added into the codeword while turbo encoding. There can be 4 different redundancy versions in LTE corresponding to new transmission, 1st, 2nd or 3rd re-transmission. Number of bits = 2. Range = 0-3.
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.
How does an ARQ check work?
In an ARQ scheme, the receiver uses an error detection code, typically a Cyclic Redundancy Check (CRC), to detect whether the received packet is in error. If an error is detected, the receiver discards the packet and sends a negative acknowledgement to the transmitter, and requests a re-transmission.
How many messages are transmitted at a time in stop-and-wait ARQ?
one frame
A stop-and-wait ARQ sender sends one frame at a time; it is a special case of the general sliding window protocol with transmit and receive window sizes equal to one in both cases. After sending each frame, the sender doesn’t send any further frames until it receives an acknowledgement (ACK) signal.
What is redundancy version in 5G?
Similar to 4G, HARQ operation and the corresponding rate matching operation of 5G LDPC codes is controlled by redundancy version (rv) from 0 to 3. Each redundancy version corresponds to a certain column position of the base graph which divides the base graph excluding punctured two columns into four chunks.
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 Harq in 5G?
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.
What is redundancy version LTE?
What is incremental-redundancy HARQ and how is it used?
LTE utilizes incremental-redundancy HARQ with a 1/3 turbo encoder used for FEC. The transport block CRC is used to detect errors. The receiver only receives different punctured versions of the same turbo-encoded data; each of these retransmissions is self-decodable. Thus, it falls into the category of a type III HARQ described earlier.
What is HARQ in LTE?
In soft combining, the bad block will not be discarded, but will be kept, and bad packets will be taken from the next re-transmitted block. This is called as HARQ. This type of HARQ is used in LTE. This is across 2 layers, between MAC and Physical Layer.
Is incremental redundancy (IR) and Chase combining (CC) supported?
– Both Incremental redundancy (IR) and Chase combining (CC) are supported. – The number of HARQ re transmissions targeted by the HARQ protocol depends on the network provided configuration. FEC or Channel Coding is a technique used for controlling and correcting error in LTE Data transmission.
When to use incremental redundancy in transmission lines?
With incremental redundancy, the code used for the first transmission should provide good performance not only when used alone, but also when used in combination with the code for the second transmission. The same holds for subsequent retransmissions.