Successive Interference Cancellation With Feedback for Random Access Networks

We consider a random access network in which <inline-formula> <tex-math notation="LaTeX">$K$ </tex-math></inline-formula> nodes wish to send independent packets to an access point (AP). In this letter, a novel method of feedback construction and an adaptive retransmission protocol of collided packets are proposed, which enable efficient successive interference cancellation at the AP. We show that the optimal throughput efficiency of one is achievable by only exploiting <inline-formula> <tex-math notation="LaTeX">$\log K$ </tex-math></inline-formula> bits of feedback from the AP to <inline-formula> <tex-math notation="LaTeX">$K$ </tex-math></inline-formula> nodes, while the maximum throughput efficiency of slotted ALOHA is known to be <inline-formula> <tex-math notation="LaTeX">$e^{-1}\approx 0.37$ </tex-math></inline-formula> for large <inline-formula> <tex-math notation="LaTeX">$K$ </tex-math></inline-formula>. Note that the proposed technique achieves the optimal throughput efficiency for any finite <inline-formula> <tex-math notation="LaTeX">$K$ </tex-math></inline-formula>, while the conventional techniques asymptotically achieve the optimal throughput efficiency only when <inline-formula> <tex-math notation="LaTeX">$K$ </tex-math></inline-formula> tends to infinity.