  The strong growth of low rate wireless personal area networks (LR-WPAN),
leads us to consider the autonomy problems, thus node lifetime in a network,
knowing that the power supplies replacement is often difficult to realize. The
inherent mobility in this type of equipment is an essential element. It will
provide routing constraints, so a complex problem to solve. This article
provides work lines to assess the performance of such a network in terms of
energy consumption and mobility. The objectives are contradictory; it will
necessarily find a compromise. In addition, if we want to guarantee a maximum
delay for the transmitted messages, possibility offered by the IEEE 802.15-4
standard, another compromise necessitate a strictly fixed structure and a fully
mobile structure. Therefore, we present a quantization of the energy cost
related to the desired data rate and compared to the sleep duration of nodes in
the network. Then, we open reflexion lines to find the best compromise:
consumption / mobility / guaranteed deadlines, in suggesting an adaptive
network structure from a concept of MANET.
