What is the Difference Between OFDM and OFDMA?

OFDM (Orthogonal Frequency Division Multiplexing) and OFDMA (Orthogonal Frequency Division Multiple Access) aretwo different modalities of OFDM. The main differences between them are as follows:

1. Precoding and Training: In OFDMA, a process called precoding (also known as soft rotation) and various training signals are used to enhance the performance of the system.
2. User Multiple Access: OFDMA allows multiple users to share the same channel by dividing the available time-frequency resources into smaller resource elements, also known as "air-interface" elements or sub-channels. This allows multiple users to use the same frequency simultaneously, providing better orthogonality and reducing interference.
3. Sub-carrier Number: OFDM perturbates the DFT of a transmission to get rid of the cycl

Comparative Table: OFDM vs OFDMA

OFDM (Orthogonal Frequency Division Multiplexing) and OFDMA (Orthogonal Frequency Division Multiple Access) are both modulation techniques used in wireless communication systems. Here is a table summarizing the key differences between OFDM and OFDMA:

OFDM is a single-user technology that supports a wider range of bandwidths and requires both LDPC and BCH for error correction. It is the primary transmission scheme in 4G LTE networks and is used in earlier Wi-Fi standards like Wi-Fi 5.

On the other hand, OFDMA is a multi-user extension of OFDM that supports a narrower range of bandwidths and only requires LDPC for error correction. It is used in the downlink direction of 4G LTE networks and is supported by later Wi-Fi standards like Wi-Fi 6. OFDMA can facilitate communication with multiple users simultaneously, making it more efficient and suitable for IoT devices, video, online gaming, and automation applications.