Optimal and Heuristic Resource Sharing Strategies for Point-to-Point Distribution in Next-Generation DSL Networks

This paper investigates resource sharing strategies in point-to-multipoint (P2MP) distribution for the next generation of digital subscriber loop (DSL) networks. The ITU-T's G-series project G.mgfast standardizes the multi-gigabit fast access to subscriber terminals (MGFAST) access technology, which aims at providing aggregated data rates of up to 10 Gbps. G.mgfast inherits multiple features from the previous DSL generation G.fast, e.g. impulse noise protection, reverse power feeding (RPF), frequency and time synchronization, etc. However, the unprecedented high data rates provided by G.mgfast are unlikely to be consumed by the users, even in the near future. Therefore, P2MP transmission has been added as a new feature for resource sharing in G.mgfast. Commonly, P2MP transmission allows resource sharing among multiple customer premises equipments (CPEs). The resource sharing is done by allocating part of the available bandwidth to each CPE connected to the same G.mgfast transceiver unit (MTU-O) at the distribution point unit (DPU). The connection of a CPE to a MTU-O is controlled digitally and dynamically by a grouping and vectoring control entity (GVCE). Moreover, the allocation of frequencies to each CPE is also flexible. However, the performance of the network is significantly affected by the allocation of CPEs to MTU-Os (i.e. the so-called grouping) and allocation of frequencies to the CPEs connected to each MTU-O (i.e. the so-called per-group frequency-division multiple access (FDMA) allocation). Hence, an optimal solution to the grouping and per-group FDMA allocation is necessary to optimally exploit the network resources. In this scenario, computing the optimal solutions involves significant computational complexity, especially when the network is dynamic, i.e., CPEs are frequently changing their activity status and traffic demands. Therefore, to overcome these issues, optimal solutions based heuristic strategies providing near-optimal performance at significantly reduced computational complexity are required. This paper proposes the optimal solutions to the grouping and per-group FDMA allocation for both upstream (US) and downstream (DS) P2MP transmission. Based on the optimal solutions, heuristics with significantly lower computational complexity are proposed, which achieve similar performances as the optimal solutions.