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Does LTE use FDMA?
LTE uses OFDM as the basic signal format – OFDMA in the downlink and SC-FDMA in the uplink with various modulation formats. OFDM forms the basic signal format used within 4G LTE.
What is FDMA in LTE?
Single-carrier FDMA (SC-FDMA) is a frequency-division multiple access scheme. It is also called linearly precoded OFDMA (LP-OFDMA). Like other multiple access schemes (TDMA, FDMA, CDMA, OFDMA), it deals with the assignment of multiple users to a shared communication resource.
What is a 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.
Which is better, OFDMA or single carrier FDMA?
One prominent advantage over OFDMA is that the SC-FDMA signal has lower peak-to-average power ratio (PAPR). SC-FDMA has drawn great attention as an attrac- tive alternative to OFDMA, especially in the uplink commu- nications where lower PAPR greatly benefits the mobile ter- minal in terms of transmit power efficiency.
How are subcarriers divided in OFDM and OFDMA?
Both OFDM and OFDMA divided a channel into subcarriers through a mathematical function known as an inverse fast Fourier transform (IFFT). The spacing of the subcarriers is orthogonal, so they will not interfere with one another despite the lack of guard bands between them.
How is SC-FDMA similar to other multiple access schemes?
Like other multiple access schemes (TDMA, FDMA, CDMA, OFDMA), it deals with the assignment of multiple users to a shared communication resource. SC-FDMA can be interpreted as a linearly precoded OFDMA scheme, in the sense that it has an additional DFT processing step preceding the conventional OFDMA processing.
What are the subcarriers for 802.11ac and OFDMA?
Just like with OFDM, there are three types of subcarriers for OFDMA, as follows: Data Subcarriers: These subcarriers will use the same modulation and coding schemes (MCSs) as 802.11ac and two new MCSs with the addition of 1024-QAM.