Self-Optimization of RACH Power Considering Multi-Cell Outage in 3GPP LTE Systems
Self-Organizing Network (SON), which is an essential technology of future radio networks, is proposed in the 3GPP Long Term Evolution (LTE) specification as a usage case. In this paper, the authors focus on User Equipment (UE)'s power control considering interference mitigation and retransmission constraints especially for Physical Random Access CHannel (PRACH) of LTE. When a UE initially accesses an evolved-NodeB (eNB), it sends a preamble with an initial access level, and raises the power by a fixed step whenever the preamble was not detected by the eNB. They present an analysis and simulation to study the tradeoff relationship between inter-cell interference and retransmission according to the PRACH power setting, i.e., the initial target received power and power ramping step, assuming Rayleigh fading channels.