Exploiting the degree of freedom in the frequency domain and the near-far effect among different access points (APs), this paper proposes an opportunistic transmission scheme in cell-free massive MIMO-OFDM systems. The key idea is to orthogonally assign subcarriers among different users, so that there is only one user on each subcarrier. Then, a user is only served by its near APs through opportunistic selection, while the far APs are deactivated to avoid wasting power over their channels with severe propagation losses. Moreover, the number of active APs per subcarrier becomes small due to the opportunistic selection, making the use of downlink pilots and coherent detection feasible. As corroborated by numerical results, the proposed scheme can bring a significant performance boost in terms of both power efficiency and spectral efficiency.
Opportunistic AP Selection in Cell-Free Massive MIMO-OFDM Systems
2022-06-01
710615 byte
Conference paper
Electronic Resource
English
On the Capacity of Nonlinear Massive MIMO-OFDM Systems
IEEE | 2016
|Channel Estimation for FDD Massive MIMO OFDM Systems
IEEE | 2017
|