Contents
What is DC subcarrier in LTE?
DC stands for Direct Current and it is a subcarrier that has no information sent on it. The OFDM signal used in LTE comprises a maximum of 2048 different subcarriers with a spacing of 15 kHz. Resource blocks include 12 subcarriers, regardless of the total LTE signal bandwidth. They also cover a slot in the time frame.
What is DC subcarrier in 5g?
DC subcarrier This is the subcarrier in the OFDM/OFDMA signal whose frequency would be equal to the RF Center frequency of the station. Generally, all devices have the DC coinciding with the center frequency. NR: DC subcarrier is used as NR devices may not be centered around the carrier frequency.
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. They are – localized, distributed and interleaved sub-carrier mapping.
What is the difference between OFDM and OFDMA subcarriers?
OFDM are sometimes also referred to as OFDM tones. In this blog series, we will use both terms interchangeably. Each OFDM subcarrier is 312.5 KHz. 802.11ax introduces a longer OFDM symbol time of 12.8 μs, which is four times longer than the legacy symbol time of 3.2 μs.
When to use a null subcarrier at DC?
The null subcarrier at DC is used to allow the use of simple (again, cheaper) direct-conversion (zero-IF) RF receivers. One disadvantage of zero-IF receivers is that they typically encounter a strong interfering signal at DC.
Which is the null subcarrier in OFDMA PHY layer?
Null subcarriers: no transmission. These are frequency guard bands. Another null subcarrier is the DC (Direct Current) subcarrier. 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.
Which is longer 802.11ax or OFDM subcarriers?
Each OFDM subcarrier is 312.5 KHz. 802.11ax introduces a longer OFDM symbol time of 12.8 μs, which is four times longer than the legacy symbol time of 3.2 μs. 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.