Flexible pilot reuse in massive MIMO with random geometric distribution of users

The fundamental limit of massive multiple-input-multiple-output (MIMO) system's performance is pilot contamination due to the reuse of the same set of pilot sequences by users in adjacent cells, which can be alleviated by assign the pilot sequences to the users appropriately, power control and many other ways. In this paper, the network model considers stochastic geometry that users are distributed according to a homogeneous Poisson point process (PPP) to simulate the real user distribution. The signal-to-interference-plus-noise (SINR) of uplink can be analytically derived, and combined with the flexible pilot reuse to simulate the reality of the pilot allocation strategy. The users suffer from severe pilot contamination use orthogonal pilot and the others with light contamination can reuse a same set of pilot sequence, ultimately get the optimal pilot reusing factor and achieve a reasonable pilot allocation.