Methods and Systems for Estimating Frequency Synchronization Accuracy
AssigneesKhalifa University of Science, Technology, and Research, British Telecommunications plc, Emirates Telecommunications Corporation
InventorsJames Aweya, Ivan Boyd
Life of this patent
Estimating the term…
Abstract
This invention relates to the use of frequency synchronization accuracy as an additional quality metric for mobile call handover between base stations. Call handover is of major importance within any mobile network; without checking frequency synchronization before handover dropped calls and interrupted communication can result.
Claims12
A method of determining handover of a mobile device between base stations in a mobile telephone network, the method including the steps of:
- monitoring, in the mobile device, the signal strengths of base stations within communication range of the mobile device and periodically communicating those signal strengths to the mobile network;
- and
- when the signal strength of the base station that the mobile device is communicating with falls below a predetermined level, initiating a handover process to determine if a suitable alternative base station is available to transfer the mobile device to, wherein
- said handover process includes the steps of:
- determining one or more quality metrics for each base station within communication range of the mobile device, the quality metrics including the accuracy of frequency synchronization of a local clock in the base station compared to a master clock;
- and
- only transferring the mobile device to communicate with an alternative base station if the quality metrics for that base station reach a predetermined level.
A base station in a mobile telephone network, the base station including a local clock and a processor, wherein the processor is arranged to:
- on receipt, from the network, of an instruction to initiate a handover process, determine one or more quality metrics for the base station, the quality metrics including the accuracy of frequency synchronization of a local clock in the base station compared to a master clock connected to the network;
- and
- communicate the determined quality metrics to the network for use in determining whether handover of a mobile device between base stations should take place.
A mobile telephone network having a plurality of base stations, the network having a first processor handling handover of mobile devices between base stations, wherein:
- each base station includes a local clock and a local processor;
- the first processor is arranged to, on receipt, from a mobile device connected to a base station in the network, of a request to initiate a handover process, request from one or more base stations within range of the mobile device one or more quality metrics for the base station, the quality metrics including the accuracy of frequency synchronization of the local clock in the base station compared to a master clock connected to the network, and determine from said quality metrics whether handover of a mobile device between base stations should take place;
- and
- the local processor is arranged to, on receipt of the request from the first processor, determine the quality metrics and communicate the determined quality metrics to the first processor.
Dependencies are inferred from the claim text.