Femtocell handset assisted clock correction

摘要

A method of improving the frequency accuracy of a clock unit for a femtocell local cellular communication home base station 10 that makes use of a mobile handset and thus avoids the need for an expensive, accurate oscillator or a receiver path to a macrocell base station 20. The method comprises: providing a local cellular communication home base station 10 having an oscillator adapted to operate as a clock therein, wherein at least one cellular communication device 30A, B, C is camped thereto, and wherein preferably the at least one camped cellular communication device 30B, 30C is further in communication with at least one neighbouring cellular communication base station 20 which is associated with an oscillator adapted to operate as a clock therein; periodically applying a derivative operator over periodically obtained local communication parameters and neighbouring communication parameters to generate derivative communication parameters over time; and correcting the frequency of the clock in the femtocell, local cellular communication home base station 10 using the derivative communication parameters over time. Preferably the local communication parameters are obtained from the at least one camped cellular communication device 30B, 30C and correspond to communication between that device and the local base station 10 and the neighbouring communication parameters are obtained from the at least one camped cellular communications device 30B, 30C and correspond to communication between that device 30B, 30C and the neighbouring base station 20. The local and neighbouring communication parameters may correspond with: the frequency associated with the oscillator of the associated base station, received signal strength indication (RSSI), received signal code power (RSCP), ratio of pilot energy to total received energy or total power spectral density (I/E), connection frame numbers and signal frame numbers (CFN, SFN).