| （英） |
The decoding performance of spatially-coupled coded slotted ALOHA systems with a finite-length packet transmission is analyzed. In these systems, the transmission is divided into multiple frames, and each frame is further divided into a plurality of slots. At a given probability, each device transmits a replica of its packet to frames, once for the current frame and subsequent d−1 frames. At the access point, first, the decoding is performed within each slot. Because the packet length is finite, packets may not be successfully decoded, even if there is no packet collision within a slot. Second, the SIC (successive interference cancellation) is carried out between slots to remove the signals which have been recovered within slots. Note that at the two ends of frames (first d − 1 and last d − 1 frames), there are fewer packets than those in the central frames. So the packets in the ends of frames have a lower probability to collide and thus are more easily decoded. This results in a wave-like decoding from ends to center. In this work, the decoding performance of spatially-coupled coded slotted ALOHA systems with finite-length packet transmission over AWGN channels is given by the density evolution. The performance of a modified systems with efficient termination of frames is also given. |