  Being an up-and-coming application scenario of mobile edge computing (MEC),
the post-disaster rescue suffers multitudinous computing-intensive tasks but
unstably guaranteed network connectivity. In rescue environments, quality of
service (QoS), such as task execution delay, energy consumption and battery
state of health (SoH), is of significant meaning. This paper studies a
multi-user post-disaster MEC environment with unstable 5G communication, where
device-to-device (D2D) link communication and dynamic voltage and frequency
scaling (DVFS) are adopted to balance each user's requirement for task delay
and energy consumption. A battery degradation evaluation approach to prolong
battery lifetime is also presented. The distributed optimization problem is
formulated into a mixed cooperative-competitive (MCC) multi-agent Markov
decision process (MAMDP) and is tackled with recurrent multi-agent Proximal
Policy Optimization (rMAPPO). Extensive simulations and comprehensive
comparisons with other representative algorithms clearly demonstrate the
effectiveness of the proposed rMAPPO-based offloading scheme.
