Non-Orthogonal Multiple Access (NOMA) is a wireless communications design believed by many to have the potential to promote massive connectivity, lower latency, improve user fairness and spectral efficiency, and increase reliability compared to the current standard orthogonal multiple access (OMA) techniques.
The basic concept behind NOMA is to serve more than one user in the same resource block such as a time slot, subcarrier, spreading code or space.
Studies show that NOMA may improve 5G operations in the future including Machine-to-Machine (M2M) communications and the Internet of Things (IoT). Performance improvement may also occur when NOMA is integrated with various effective wireless communications techniques, such as cooperative communications, multiple-input multiple-output (MIMO), beamforming, space–time coding, network coding, full-duplex, etc.
Given all advancements and experimental outcomes, standardization of NOMA has been established for the next-generation American digital TV standard (ATSC 3.0) under the term layered-division multiplexing (LDM), and has been initiated for the third generation partnership project (3GPP) under the name multi-user superposition transmission (MUST).
NOMA is often regarded as an “add-on,” which means it has the potential to be harmoniously integrated with existing MA techniques. At NOMA’s core is to utilize power and code domains in multiplexing to support more users in the same resource block.
With NOMA, because the limited spectrum resources can be fully utilized to support more users, the capacity of 5G networks can be improved significantly even though extra interference and additional complexity will be introduced at the receiver.
Key features of NOMA include:
- Improved SE (spectrum efficiency): NOMA exhibits a high SE, which is attributed to the fact that it allows each resource block to be exploited by multiple users.
- Relaxed channel feedback: In NOMA, perfect uplink CSI is not required at the base station (BS). Instead, only the received signal strength needs to be included in the channel feedback.
- Low transmission latency: In the uplink of NOMA, there is no need to schedule requests from users to the BS, which is normally required in OMA schemes. As a result, a grant-free uplink transmission can be established in NOMA, which reduces the transmission latency drastically.
- Ultra-high connectivity: With the capability to support multiple users within one resource block, NOMA can potentially support massive connectivity for billions of smart devices. This feature is quite essential for IoT scenarios with users that only require very low data rates but with massive number of users.
Want to learn more? Tonex offers Non-Orthogonal Multiple Access (NOMA) Training, a 3-day course that covers next major phase of wireless and mobile telecommunications standards beyond the current 4G/IMT-Advanced standards with a focus on novel NOMA modulation and coding scheme for the air interface.
Additionally, Tonex offers 20 more cutting edge 5G Wireless courses with titles like:
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