Energy efficient coded random access for the wireless uplink
Name
1907.09448.pdf
Description
Submitted version
Size
392.25 KB
Format
Unknown
Checksum (MD5)
cba55bbbf4eaada032c67bd5ed2a05a4
Author(s)
Kowshik, Suhas S
Andreev, Kirill
Frolov, Alexey
Polyanskiy, Yury
Date Issued
2020
Journal
IEEE Transactions on Communications
Publisher
Institute of Electrical and Electronics Engineers (IEEE)
Version
Original manuscript
Abstract
© 1972-2012 IEEE. We discuss the problem of designing channel access architectures for enabling fast, low-latency, grant-free, and uncoordinated uplink for densely packed wireless nodes. Specifically, we study random-access codes, previously introduced for the AWGN MAC, in the practically more relevant case of Rayleigh fading, when channel gains are unknown to the decoder. We propose a random coding achievability bound, which we analyze both non-asymptotically and asymptotically. As a candidate practical solution, we propose an explicit iterative coding scheme. The performance of such a solution is surprisingly close to the finite blocklength bounds. Our main findings are twofold. First, just like in the AWGN MAC, we see that jointly decoding a large number of users leads to a surprising phase transition effect, where, at spectral efficiencies below a critical threshold, a perfect multi-user interference cancellation is possible. Second, while the presence of Rayleigh fading significantly increases the minimal required energy-per-bit, the inherent randomization introduced by the channel makes it much easier to attain the optimal performance via iterative schemes. We hope that a principled definition of the random-access model, together with their information-theoretic analysis, will open the road towards unified benchmarking and performance comparison of various random-access solutions for the 5G/6G.
MIT Department
Massachusetts Institute of Technology. Laboratory for Information and Decision Systems
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Terms of Use
Creative Commons Attribution-Noncommercial-Share Alike
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1109/TCOMM.2020.3000635
