What is subcarrier spacing in LTE?
In LTE, each subcarrier is spaced 15 kHz apart. These subcarriers are combined in groups of 12 to form a single resource block. Each resource block is used in an OFDMA arrangement to send data to different handsets or combined for high-speed data.
What is the space between a subcarrier and the next sub carrier in an LTE network?
The LTE OFDM subcarrier spacing equals 15 kHz for both downlink and uplink.
What are resource blocks in LTE?
A resource block (RB ) is the smallest unit of resources that can be allocated to a user. The resource block is 180 kHz. wide in frequency and 1 slot long in time.
What is downlink and uplink in LTE?
The actual implementation of the technology will be different between the downlink (i.e. from base station to mobile) and the uplink (i.e. mobile to the base station) as a result of the different requirements between the two directions and the equipment at either end.
What is subcarrier spacing common?
In LTE, there is only type of numerology or subcarrier spacing (15 KHz), whereas in NR, multiple types of subcarrier spacing are available e.g 5G NR supports subcarrier spacing of 15, 30, 60, 120 and 240 KHz.
What is the meaning of subcarrier spacing?
Subcarrier spacing is equal to the reciprocal of the symbol time. As a result of the longer symbol time, the subcarrier size and spacing decreases from 312.5 KHz to 78.125 KHz. The narrow subcarrier spacing allows better equalization and therefore enhanced channel robustness.
What is a subcarrier spacing?
What is subcarrier frequency?
There are usually at frequencies of 5.8, 6.2, or 6.8 MHz (the video carrier usually resides below 5 MHz on a satellite transponder or microwave relay). Extra subcarriers are sometimes transmitted at around 7 or 8 MHz for extra audio (such as radio stations) or low-to-medium-speed data.
What is RB and PRB in LTE?
RB (Resource Block) and PRB (Physical Resource Block) are exactly the same. 12 subcarriers x 7 symbols. The green rectangular in your image is correct. PRB is usually used to differentiate Resource Block from RB (Radio Bearer).
Why downlink is higher than uplink?
Since a mobile station (cellphone) cannot afford to transmit at high power to compensate for this loss, it must transmit on a lower frequency as a lower frequency presents lesser free space path loss. Therefore, mobile-to-base station (uplink) frequencies are lower than base station-to-mobile(downlink) frequencies.
What is uplinking and downlinking?
In satellite telecommunication, a downlink is the link from a satellite down to one or more ground stations or receivers, and an uplink is the link from a ground station up to a satellite. Some companies sell uplink and downlink services to television stations, corporations, and to other telecommunication carriers.
Which subcarrier spacing do we use for high band?
The specific set of subcarrier spacing values depends on the exact frequency band. For example, 28 GHz and 39 GHz mmW spectrum bands can use the subcarrier spacing of 60 kHz and 120 kHz.
What is the difference between carrier and subcarrier?
There is no physical difference between a carrier and a subcarrier; the “sub” implies that it has been derived from a carrier, which has been amplitude modulated by a steady signal and has a constant frequency relation to it.
What is subcarrier spacing in 5G?
5G NR can choose subcarrier spacing from 15kHz to 240kHz, with a maximum 3300 subcarriers in simultaneous use on one channel. However, channels can be no more than 400MHz wide. The standard is frequency agnostic, meaning any subcarrier configuration can be used on any band.
What is a pilot subcarrier?
Pilot subcarriers transmit with a known data sequence. This information is used to determine the difference, or error, between an ideal signal and the actual received signal. Because the data is complex, the VSA calculates phase, amplitude, and timing error data.
What is subcarrier spacing?
What is subcarrier mapping?
Sub-carrier mapping is one of the major considerations for LTE as multiple mobile terminals i.e. users are assigned by partitioned subcarriers in OFDMA system. In LTE uplink a subsets of subcarriers are used to transmit its own data.
What is DC subcarrier?
DC stands for Direct Current and it is a subcarrier that has no information sent on it. This is an important subcarrier in OFDM based systems. It is used by the mobile device to locate the center of the OFDM frequency band. So, if LTE does not have a DC subcarrier, it would be a big deal.
Which is fast uplink or downlink?
In the uplink broadband (speed) and downlink broadband (speed), the downlink speed is generally greater than the uplink speed. Because the broadband we use usually says how much M refers to the downlink broadband, because we mainly download data from the Internet, and the amount of uploaded data is much less.
What does Downlinking mean?
In satellite telecommunication, a downlink is the link from a satellite down to one or more ground stations or receivers, and an uplink is the link from a ground station up to a satellite.
Why uplink is lower than downlink?
What is subcarrier bandwidth?
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 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 a subcarrier frequency?
What is the LTE standard for subcarrier shift and phase reset?
standard regarding subcarrier shift and phase reset. The LTE standard requires that the uplink subcarriers be spaced on either side of DC by half the subcarrier spacing. When this is done, a phase reset is also needed after each symbol.
What is the half-subcarrier shift for LTE uplinks?
For the uplink, a half-subcarrier shift is a key consideration for DSS. The LTE uplink has a 7. 5-kHz offset to avoid the use of the DC subcarrier, but not NR. The DC subcarrier is used for NR uplink transmission. The 7. 5-kHz offset will break the orthogonality of LTE and NR. Adding a 7.
What is the ideal subcarrier spacing for LTE?
Consequently, a subcarrier spacing in the LTE range or somewhat higher, in the range of 15-30 kHz, was needed. For higher carrier frequencies approaching the mm-wave range, implementation limitations such as phase noise become more critical, calling for higher subcarrier spacings.
What is the bandwidth of a subcarrier?
). The resource element, which is 1 subcarrier x 1 symbol, is the smallest discrete part of the frame and contains a single complex value representing data from a physical channel or signal. The bandwidths defined by the standard are 1.4, 3, 5, 10, 15, and 20 MHz.