  Energy preservation is one of the most important challenges in wireless
sensor networks. In most applications, sensor networks consist of hundreds or
thousands nodes that are dispersed in a wide field. Hierarchical architectures
and data aggregation methods are increasingly gaining more popularity in such
large-scale networks. In this paper, we propose a novel adaptive
Energy-Efficient Multi-layered Architecture (EEMA) protocol for large-scale
sensor networks, wherein both hierarchical architecture and data aggregation
are efficiently utilized. EEMA divides the network into some layers as well as
each layer into some clusters, where the data are gathered in the first layer
and are recursively aggregated in upper layers to reach the base station. Many
criteria are wisely employed to elect head nodes, including the residual
energy, centrality, and proximity to bottom-layer heads. The routing delay is
mathematically analyzed. Performance evaluation is performed via simulations
which confirms the effectiveness of the proposed EEMA protocol in terms of the
network lifetime and reduced routing delay.
