Adaptive Pilot Allocation for Multi-Cell Massive MIMO Systems

In the upcoming 5G system, the massive MIMO technology will perform an important role in significantly improving the system performance. To sufficiently exploit the potential of massive MIMO, the transceiver should perform appropriate accurate channel estimation, including carefully designed quantities of pilot resource and its allocation among different users. In this letter, a low-complexity adaptive pilot allocation algorithm using the second-order channel statistics of all users is proposed, which helps in finding a good balance between the allocated pilot length and pilot training interference. Numerical results indicate that the proposed algorithm can significantly improve the net spectrum efficiency in multi-cell massive MIMO systems.