What is the Difference Between OFDM and OFDMA?
🆚 Go to Comparative Table 🆚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:
- 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.
- 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.
- 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:
Feature | OFDM | OFDMA |
---|---|---|
Single-user vs. Multi-user | Single-user | Multi-user |
Bandwidth Support | 24 MHz to 192 MHz | 6.4 MHz to 96 MHz |
Error Correction | Low Density Parity Check (LDPC) and extra layer of error correction called BCH | LDPC only |
Use in 4G LTE | Primary transmission scheme | Multi-user version of OFDM used in downlink communication |
Supported by Wi-Fi Standards | Wi-Fi 5 and earlier | Wi-Fi 6 and later |
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.
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