Distributed PCI Assignment in LTE Based on Consultation Mechanism

Physical Cell Identity (PCI) is cell identifier on the physical layer which can be used to create synchronization signals. There is a mapping between synchronization signals and physical cell identity, and then User Equipment (UE) can search cells through this mapping. Traditionally, PCI was configured during network planning process. While with 3G Long Term Evolution (LTE) has been prevalent in the future network, auto configuration of radio parameters has become a necessity. This paper proposed a distributed PCI assignment method based on consultation mechanism for automatic configuration of locally-unique PCI. This method which is implemented in eNBs, first receives a PCI list from OAM, and then obtains the neighbor information through interaction between X2 interfaces of eNBs; in particular, a consultation mechanism is required by the candidate eNBs to determine sequence and time for responding to the initiated eNBs when more than one eNB request for neighbor cell information. After that, the initiating eNB is responsible to create suitable PCIs for its cells from the PCI list which exclude the PCIs appeared in neighbor cells.