  Improving energy efficiency is vital for the 5G mobile telecommunication
network, while the conventional temporal shutdown strategy is exhausting its
energy-saving potential. Inspired by the symmetricity between the temporal
peaks and valleys and the geographical hot and cold-spots in network traffic,
we propose a new strategy for telecom energy-saving which matches the base
station cells with traffic hotspots as much as possible to reduce waste. We
showed deductively and empirically that the probability density function of the
spatial distribution of network traffic typically has a steep power-law form,
which gives rise to temporally stable traffic hotspot areas that occupies only
about 13% of the space and also have proper sizes suitable for spatial
optimization. A simplified model hence built yields up to 19.59% energy savings
for the 4G network, and 29.68% for a hypothetical 5G network, prominent margins
over what the temporal shutdown approach would gain.
