NETWORK-BASED CELL IDENTIFICATION COLLISION DETECTION IN WIRELESS COMMUNICATIONS

摘要

The present invention relates to the detection of local cell identifier collisions by a base station. For purposes of identification, each base station in the network 200 may include a local cell identifier (e.g., a physical cell identifier (PCI), a pilot pseudo-random number (PilotPN), or the like) intended to be unique in a given geographic area Other types of identifiers) may be assigned or otherwise selected. Due to the limited geographical range, the local cell identifier can use a relatively small number of bits and is still (locally) inherent in a defined area. However, for the same reason, the amount of local cell identifiers defined in a given system is limited (e.g., from one to several hundreds in some systems). In FIG. 2, femto base stations 210 and 212 may be used in macro networks to adjust the distribution of local cell identifiers, possibly in large numbers throughout the home, apartment building, office building, And may be deployed by individual consumers without a centralized plan. In this way, identifier conflicts and associated problems among base stations in mixed networks as well as in femto networks are likely to be broader and more detrimental than in conventional macro networks where deployment and base station identification are more closely controlled . In one particular type of interrogation, referred to as the identifier "collision ", two neighboring base stations cause a user device in the region to transmit a signal (e.g., a signal containing the same local cell identifier) from two different distinct base stations The same local cell identifier may be used by chance in such a manner as to simultaneously receive the pilot signal. The resulting identifier collision between femto base stations 210 and 212 may lead to several problems. Therefore, the present application proposes to detect the following collision. The femto base station 210 determines that the received PCI in the RRCConnectionReestablishmentRequest message is consistent with its own PCI (i.e., the PCI of the femto base station 210), but the c-RNTI does not know that the femto base station 210 has received any Does not match any of the c-RNTIs assigned to the user device (e. G., User device 222). Accordingly, the femto base station 210 may determine that the RRCConnectionReestablishmentRequest message is another neighboring base station using the same PCI as the femto base station 210 (i.e., the femto base station 212 in this example, but its identity may not be known to the femto base station 210) It is determined that it was actually intended for.