Nested Multi-Agent Reinforcement Learning for Adaptive Resource Management in 6G Network Slicing: A Multi-Timescale Framework With Convergence Guarantees
Sixth-generation (6G) networks are expected to rely on agentic artificial intelligence for zero-touch, self-managed orchestration of heterogeneous network slices serving enhanced mobile broadband (eMBB), ultra-reliable low-latency communication (URLLC), and massive machine-type communication (mMTC). A central and under-studied challenge for adaptive multi-agent resource management (AMRM) in such settings is multi-timescale non-stationarity: channel fading evolves per time-slot, user demand shifts at the window scale, and service-level agreement (SLA) regimes change at an operational scale. Single-timescale multi-agent reinforcement learning (MARL) algorithms cannot track all three signals cleanly—a learning rate fast enough for the per-slot channel destabilises the coordination structure that governs longer-timescale policies. This paper proposes Nested-MARL, an independent-learner actor-critic algorithm in which each agent’s parameters are partitioned into three groups updated at separated rates <inline-formula> <tex-math notation="LaTeX">$\alpha _{0}\!\ll \!\alpha _{1}\!\ll \!\alpha _{2}$ </tex-math></inline-formula>, with a continuum-memory exponential moving average (EMA) anchoring the slowest group. The design is grounded in the Nested Learning paradigm of Behrouz et al. (2025) and is extended here from single-model continual learning to decentralised multi-agent coordination. We establish a finite-time convergence result in the two-timescale stochastic approximation framework showing that under standard regularity and timescale-separation conditions, Nested-MARL achieves <inline-formula> <tex-math notation="LaTeX">$O(T^{-1/2})$ </tex-math></inline-formula> fast-group convergence vs. an <inline-formula> <tex-math notation="LaTeX">$\Omega (T^{-1/3})$ </tex-math></inline-formula> lower bound for any single-timescale algorithm. An empirical study on a three-agent 6G slicing simulator with continuous multi-timescale drift shows Nested-MARL outperforms independent PPO (IPPO) in mean reward at every drift severity we test (<inline-formula> <tex-math notation="LaTeX">$\kappa \!\in \!\{0.5,1.0,1.5,2.0\}$ </tex-math></inline-formula>) and by + 8.6% in sample efficiency over the first 40 episodes at <inline-formula> <tex-math notation="LaTeX">$\kappa {=}1.5$ </tex-math></inline-formula> (<inline-formula> <tex-math notation="LaTeX">$n{=}10$ </tex-math></inline-formula> seeds, <inline-formula> <tex-math notation="LaTeX">$p\lt 0.05$ </tex-math></inline-formula>). A controlled ablation establishes that stripping timescale separation reduces performance below the IPPO baseline, isolating timescale separation as the causal mechanism. Nested-MARL also reduces policy switching cost by 16.6%, an operationally meaningful benefit for zero-touch orchestration. The complete simulator, agents, and 60 + per-seed training runs are released as open source.