LTE FDD Physical Random Access Channel Dimensioning and Planning

A User Equipment (UE) can only be selected for uplink transmission if it is time-synchronized, so that the Physical Random Access Channel (PRACH) becomes a key factor between non-synchronized UEs and the orthogonal LTE uplink access scheme. An appropriate design is essential to provide frequent enough random access opportunities and an accurate UE synchronization estimation to adapt to different cell ranges and network conditions without using unnecessary resources, which would lead to a decrease in uplink capacity. However, all these requirements make a robust design be a very complex procedure. This paper proposes a novel algorithm for LTE FDD PRACH dimensioning and planning that accurately estimates the required resources and assigns them minimizing the probability of wrong preamble detection by means of an uncoupled optimization process that can be efficiently applied by operators on real networks.