Colloquium / Seminars
Topic：Random and Deterministic Schemes for a Collision Channel without Feedback
Speaker：Prof. Yuan-Hsun Lo
(Dept. Applied Mathematics, National Pingtung University)
Date time：Dec. 22, 2020 14:00 –15:00
Tea Party：Dec. 22, 2020 13:30
There are two main medium access control (MAC) approaches to a slot-synchronous collision channel without feedback: random (slotted ALOHA) and deterministic (protocol sequence-based) schemes. Unlike the traditional slotted ALOHA, protocol sequence-based scheme is a deterministic way to guarantee a positive individual throughput within an expectable period of time, even the time synchronous is hard to be achieved. In the first part of this talk, I will survey some results on protocol sequence-based schemes, including user-irrepressible (UI) sequences and conflict-avoiding codes (CACs), which have some interesting combinatorial structures. Then, for a fair comparison, deadline-constrained slotted ALOHA schemes will be introduced to maximize the probability that a packet can be successfully received within an pre-assigned deadline. Some recent progress including the uniqueness of the optimal transmission probability that maximizes the successful delivery probability under multiple-packet reception (MPR) technology is addressed as well.