In the original version of this article, the channel bandwidth B was missing in the definition of energy efficiency and the total number of users was inadvertently removed in the simulation scripts of energy efficiency. As a result, the following corrections are needed.
The sentence in the beginning of Section 3, “Define energy efficiency as ηe = ηs/Pavg, where ηs is”, should be written as “Define energy efficiency as ηe = B·ηs/Pavg, where B is the channel bandwidth, ηs is”. Equations (10) and (18) should have a multiplication constant B in their numerators:
In the right subfigure of Figure 3, the unit of Y-axis should be “Mbits/Joule”, i.e., 106 bits/Joule, and the Y-axis labels should be “24, 48, 72, 96, 120, 144, 168, 192, 216, 240, 264”. The correct subfigure is shown as follows:
In Fig. 4, the unit of Y-axis should be “Mbits/Joule” and the Y-axis labels should be “0, 48, 96, 144, 192, 240, 288”. The correct Fig. 4 is shown as follows:
As the channel bandwidth in this article is fixed at 10 MHz and the total number of users is fixed at 48, the above errors do not affect the optimization results in Section 3 or the energy efficiency comparisons in Section 5. We apologize to our readers for these errors.