Table 2 Comparison of computational complexity

Nie and Zhao [10]

Joint pilot allocation and pilot sequences optimization

\(O(KL)^3\)

Shahabi et al. [12]

CEP with limited cooperation among cells to reduce overheads

\(O (MKL^2)\)

Ma et al. [31]

Joint optimization pilot allocation

\(O (KL^2 \mathrm{log}L)\)

Mei et al. [32]

ZF-PCP

\(O((K)^L)\)

Liu et al. [33]

Near MMSE precoder using the parametric model

\(O(TKL)^2\)