SAMA Successive interference cancellation amenable multiple access

SAMA (Successive Interference Cancellation Amenable Multiple Access) is a multiple access technique used in wireless communication systems. It is designed to improve the efficiency of accessing the shared wireless medium by mitigating interference between different users.

Multiple access refers to the ability of multiple users to share the same wireless channel simultaneously. In wireless communication systems, such as cellular networks, there are typically multiple users trying to transmit data over the air interface at the same time. Multiple access techniques are employed to allow these users to share the limited resources of the wireless channel efficiently.

SAMA is a particular multiple access technique that utilizes successive interference cancellation (SIC) to mitigate interference between users. It is based on the principle that a receiver can cancel out the interference caused by one user's signal if it has knowledge of that signal and can separate it from other interfering signals.

Here's how SAMA works in detail:

1. User Transmission: In SAMA, each user is assigned a specific time/frequency slot for transmission. Users send their signals simultaneously over the shared wireless channel.
2. Signal Reception: At the receiver, multiple user signals arrive simultaneously, causing interference. The receiver captures the combined signal, which consists of the desired signal from the intended user and interference from other users.
3. Signal Separation: SAMA employs a multi-stage process known as successive interference cancellation (SIC) to separate the individual user signals from the combined received signal. In each stage, the receiver attempts to cancel the interference caused by one user, thereby isolating the signal of interest.
4. Initial Decoding: In the first stage of SIC, the receiver decodes the strongest user signal that exhibits the highest received power. This signal is assumed to have the least interference from other users.
5. Interference Cancellation: Once the initial decoding is performed, the receiver subtracts the estimated signal of the successfully decoded user from the received signal. This cancellation process removes the interference caused by the decoded user, improving the overall signal quality.
6. Iterative Decoding: After interference cancellation, the receiver repeats the decoding process for the remaining users. The next strongest signal is decoded, and its estimated signal is subtracted from the received signal to cancel its interference.
7. Repeated Stages: The iterative decoding process continues until all user signals have been decoded and their interference has been canceled. Each stage improves the quality of the remaining signals, as interference is progressively eliminated.
8. Final Decoding: Once all interference cancellation stages are completed, the receiver performs the final decoding of the remaining user signals. The decoded signals are then processed further for error detection and correction.

SAMA offers several advantages in multiple access scenarios. By employing SIC, it allows users to share the wireless medium more efficiently by canceling out interference. It improves the overall system capacity, enabling more users to transmit simultaneously. However, SAMA also requires additional complexity in both the transmitter and receiver, as well as precise timing synchronization and channel estimation techniques to achieve effective interference cancellation.

Overall, SAMA is a powerful multiple access technique that enables interference mitigation and efficient utilization of wireless resources in communication systems.