Wireless Communications and Mobile Computing / 2018 / Article / Fig 1

Research Article

Rate-Adaptive Multiple Access for Uplink Grant-Free Transmission

Figure 1

Illustrations of MAC, grant-free transmission, and RAC models. and are the messages to be transmitted.
(a) Grant-free model
(b) Network-oriented model (erasure channel model)
(c) MAC model
(d) RAC model