What is basic principle of OFDM?
The basic principle of OFDM is to split a high-rate datastream into a number of lower rate streams that are transmitted simultaneously over a number of subcarriers.
What is OFDM mode?
In telecommunications, orthogonal frequency-division multiplexing (OFDM) is a type of digital transmission and a method of encoding digital data on multiple carrier frequencies. In OFDM, multiple closely spaced orthogonal subcarrier signals with overlapping spectra are transmitted to carry data in parallel.
How many types of PHY layers are used in WLAN?
The 802.11 protocol operates in two very specific layers of the OSI model; LAYER 1 and LAYER 2. Lets look closely at those layers and detail what happens at each layer. LAYER 1 – Layer 1 has 2 sub layers (PLCP) Physical Layer Convergence Procedure and (PMD) Physical Medium Dependent.
What is the difference between OFDM and Ofdma?
OFDMA stands for orthogonal frequency division multiplexing access. It is an extension of OFDM. The difference is that OFDMA is multi-user where OFDM is single-user. It has 3x higher throughput than single-user OFDM for short packets of data or multiple endpoints.
What are the problems in OFDM?
Typically linearity, image rejection, phase distortion and phase noise issues for OFDM are addressed through the addition of costly and power-hungry external components including surface acoustic wave (SAW) filters and crystal oscillators that contribute to a higher system bill of materials (BOM) and increased power …
What does orthogonal mean in OFDM?
In a perfect OFDM signal, Orthogonality prevents interference between overlapping carriers. In FDM systems, any overlap in the spectrums of adjacent signals will result in interference. In OFDM systems, the subcarriers will interfere with each other only if there is a loss of orthogonality.
What are the main features of OFDM?
Key features of OFDM
- Multiple carriers (called subcarriers) carry the information stream.
- The subcarriers are orthogonal to each other.
- A guard interval is added to each symbol to minimize the channel delay spread and intersymbol interference.
Why OFDM is efficient?
Why OFDM Is Efficient? OFDM, like FDM, separates the channel bandwidth into multiple narrow-band subcarriers to carry the information. This not only permits the removal of the guard bands, but since the subcarriers are completely unrelated, they can even overlap each other. This is why OFDM is so bandwidth efficient.
What is WLAN PHY?
Wi-Fi: Overview of the 802.11 Physical Layer and Transmitter Measurements. Introduction. Wi-Fi is a technology that allows many electronic devices to exchange data or connect to the internet wirelessly using radio waves.
What is wireless PHY?
A PHY, an abbreviation for “physical layer”, is an electronic circuit, usually implemented as an integrated circuit, required to implement physical layer functions of the OSI model in a network interface controller.
What is downstream OFDM?
OFDM is used in the downstream and is a common channel shared by all compatible cable modems. OFDMA is used in the upstream by cable modems transmitting data to the CMTS.