Question: What Is Subcarrier Spacing?

What is subcarrier spacing in LTE?

The LTE OFDM subcarrier spacing equals 15 kHz for both downlink and uplink.

The selection of the subcarrier spacing in an OFDM-based system needs to carefully balance overhead from the cyclic prefix against sensitivity to Doppler spread/shift and other types of frequency errors and inaccuracies..

What is subcarrier in OFDM?

OFDM divides a given channel into many narrower subcarriers. The spacing is such that the subcarriers are orthogonal, so they won’t interfere with one another despite the lack of guard bands between them. This comes about by having the subcarrier spacing equal to the reciprocal of symbol time.

What is subcarrier frequency?

A subcarrier is a sideband of a radio frequency carrier wave, which is modulated to send additional information. Examples include the provision of colour in a black and white television system or the provision of stereo in a monophonic radio broadcast.

What is Coreset in 5g?

In 5G NR, CORESET is known as Control Resource Set. It is a set of physical resources within a specific area in Downlink Resource Grid and used to carry PDCCH (DCI). … Frequency allocation in a CORESET configuration can be contiguous or non-contiguous.

What does the DC subcarrier indicate?

What does the DC subcarrier indicate? Explanation: All the subcarriers of an OFDM symbol do not carry useful data. In OFDM and OFDMA PHY layers, the DC subcarrier is the subcarrier whose frequency is equal to the RF centre frequency of the transmitting station.

What is subcarrier spacing in 5g?

Numerologies One major new feature of 5G is multiple numerologies which can be mixed and used simultaneously. A numerology is defined by its subcarrier spacing (the width of subcarriers in the frequency domain) and by its cyclic prefix. 5G defines a base subcarrier spacing of 15 kHz.

What is mini slot in 5g?

Me: It is the minimum scheduling unit used in 5G NR, it occupies 2, 4 or 7 OFDM symbols (regardless of numerology), so a user can be allocated a mini-slot which is less than the slot (14 symbols) and it is suitable for low latency communication.

What is subcarrier LTE?

3) An entity consisting of a orthogonal symbol (0.071428 ms) & one subcarrier (15khz) is known as Resource Element (RE). So a LTE radio frame consists of 10 subframes (i.e. total 1 ms) in time domain & 72 subcarriers (i.e. total 1080 Khz) in freq domain.

What is the value of subcarrier spacing in 4g?

In addition to this the subcarriers spacing is 15 kHz, i.e. the LTE subcarriers are spaced 15 kHz apart from each other. To maintain orthogonality, this gives a symbol rate of 1 / 15 kHz = of 66.7 µs. Each subcarrier is able to carry data at a maximum rate of 15 ksps (kilosymbols per second).

How does LTE calculate PRB?

Physical Resource Block (PRB) = 2*Resource Block = 12 Subcarriers x 14 OFDM in 1ms. RE can deliver 2, 4, 6, 8 bits in QPSK, 16QAM, 64QAM, 256QAM respectively. If we calculate for 64QAM as 6bits since 256QAM not widely spread (check Samsung S7 in T-Mobile). 20MHz ==> 100 PRB ==> 100*168*1000 = 16,800,000 RE in 1 s.

Is OFDM used in 5g?

Orthogonal Frequency Division Multiplexing (OFDM) is an efficient modulation format used in modern wireless communication systems including 5G. OFDM combines the benefits of Quadrature Amplitude Modulation (QAM) and Frequency Division Multiplexing (FDM) to produce a high-data-rate communication system.

What is Numerology in 5g?

©3G4G In the context of 3GPP 5G standardization contributions, the term numerology refers to the configuration of waveform parameters, and different numerologies are considered as OFDM-based sub-frames having different parameters such as subcarrier spacing/symbol time, CP size, etc.

It is not possible to use OFDMA on the uplink since, as told before, it presents a high Peak-to-average Power Ratio. On SC-FDMA before applying the IFFT the symbols are pre coded by a DFT (Discrete Fourier Transform). … This way each subcarrier after de IFFT will contain part of each symbol.

Why OFDM is better than CDMA?

Both OFDM and CDMA have significant benefits. OFDM can combat multipath interference with greater robustness and less complexity. … OFDMA can achieve higher spectral efficiency with MIMO than CDMA using a RAKE receiver. Cell breathing does not occur as additional users connect to the base station.

Why OFDM is efficient?

The OFDM is a very efficient modulation technique that can achieve very high throughput by transmitting on a great number of carriers simultaneously. It is also very spectrally efficient because of the proximity of the subcarriers.