Calculate power of an LTE Signal
Assuming the power spectral density (watts per Hz) are constant then take the overall power of 23 dBm and convert it to real power: -

$$\text{real power} = 10^{\frac{23}{10}} = 200 \text{ mW} $$

Next divide that by bandwidth (10 MHz) to get power per Hz: -

$$ 20 \text{ nano watts per Hz}$$
$$ = -77 \text{ dBW per Hz}$$
$$ = -47 \text{ dBm per Hz}$$