Physical-Layer Multicasting Design for Downstream G.fast DSL Transmission

Wouter Lanneer,Marc Moonen,Ya-Feng Liu,Wei Yu

doi:10.1109/access.2019.2928451

Abstract

This paper studies the physical-layer multicasting design for downstream G.fast digital subscriber line (DSL) transmission, which corresponds to a multi-user multi-tone (i.e., multi-carrier) scenario. The design goal is to maximize the weighted-sum-group-rate (WSGR) under per-line power constraints. First, as an information-theoretic upper bound, full-rank precoding-based multicasting is considered with joint channel coding across tones. For a single multicast group, this problem corresponds to a non-linear convex semidefinite program (SDP), which is coupled across tones. To reduce the computational complexity, a Lagrange dual decomposition method is developed. This approach is then extended toward multiple multicast groups based on difference-of-convex (DC) programming. Furthermore, a practical multicasting scheme is considered based on rank-one single-stream precoding and independent per-tone channel coding. For this case, instead of relying on computationally complex semidefinite relaxation, a successive convex approximation-based trust-region algorithm is developed. Finally, the simulations of a G.fast cable binder show that the practical multicasting scheme operates close to the information-theoretic multicasting upper bound.

Highlights

Introduced by the International Telecommunication Union (ITU), G.fast [2] is the digital subscriber lines (DSL) access technology that marks the beginning of ‘‘ultra-broadband copper access’’ by offering gigabit transmission speeds
MAIN CONTRIBUTIONS In this paper, the physical-layer multicasting design problem of maximizing the WSGR is considered for downstream G.fast DSL transmission, which corresponds to a multi-user multi-tone scenario
This paper studied physical-layer multicasting design for downstream G.fast DSL transmission, which corresponds to a multi-user multi-tone scenario

Summary

INTRODUCTION

Introduced by the International Telecommunication Union (ITU), G.fast [2] is the digital subscriber lines (DSL) access technology that marks the beginning of ‘‘ultra-broadband copper access’’ by offering gigabit (i.e. fiber-like) transmission speeds. A. MAIN CONTRIBUTIONS In this paper, the physical-layer multicasting design problem of maximizing the WSGR is considered for downstream G.fast DSL transmission, which corresponds to a multi-user multi-tone (i.e. multi-carrier) scenario. The second part of this paper considers a practical rank-one single-stream precoding based multicasting scheme, together with independent per-tone channel coding, such that users of the same multicast group communicate at the same bit-rate on every tone independently, according to the minimum SINR value. For this case a trust-region method based on SCA is proposed to maximize the WSGR. Expectation,[X]ij as the i, j-th element of X, Tr {.} as trace, diag(x) a diagonal matrix with x on the diagonal, | · | as the scalar absolute value, and 1 as a vector of ones

SYSTEM MODEL

MULTI-GROUP MULTICASTING

RANK-ONE ZF-PRECODING

CONCLUSION