Ubiquitous computing environments are characterised by a diversity of mobile nodes and networks, and in particular, mobile ad-hoc networks. Mobile Ad-hoc NETworks (MANETs) are self-organising networks that lack a fixed infrastructure, and due to nodes arrivals, departures, crashes and movements, they are very dynamic networks. The topology changes occur both rapidly and unexpectedly and nodes (processes) can dynamically enter and leave the system. Thus, a distributed system built over MANETs can be partitioned. Distributed systems that are built over MANETs must be partition-tolerant, that is network partitioning may result in a degradation of services, but not necessarily in their unavailability. Fault-tolerant applications in partitionable system models generally rely on the two services of Group Communication System: (1) group membership service and (2) reliable multicast service. Informally, group membership specifies the view a process has on the current group it belongs to whereas reliable multicast provides reliable message diffusion within the same group. In this work, we focus on the group membership service, and more precisely, on group membership services for partitionable systems built over MANETs.