Re-synchronization method for a communication device

A cellular communication system comprising:

• a plurality of cells having radio base stations covering said cells;
• at least one communication device for communicating with one of said radio base stations, said communication device having
• a master timer controlling internal timing of said communication device relative to a first timing reference of said one of said radio base stations,
• means for initially synchronizing said master timer to said first timing reference,
• means for determining and storing a first channel profile of received multi-path signals relative to said initial synchronization,
• means for entering a sleep mode after said initial synchronization, in said sleep mode a second timing reference that controls said master timer being switched off,
• means for entering a receive mode from said sleep mode, in said receive mode, said second timing reference being switched on,
• means for determining, in said receive mode, a second channel profile of received multi-path signals,
• means for deriving a timing offset signal from a best fit obtained by fitting said first channel profiled to said second channel profile, and
• means for re-synchronizing said master timer on the basis of said derived timing offset signal;
• wherein said communication device comprises mean-square error fitting means to perform said fitting.

A communication device for use in a cellular communication system having a plurality of cells with radio base stations covering said cells, said communication device being configured to communicate with one of said radio base stations, said communication device comprising:

• a master timer controlling internal timing of said communication device relative to a first timing reference of said one of said radio base stations,
• means for initially synchronizing said master timer to said first timing reference,
• means for determining and storing a first channel profile of received multi-path signals relative to said initial synchronization,
• means for entering a sleep mode after said initial synchronization, in said sleep mode a second timing reference that controls said master timer being switched off,
• means for entering a receive mode from said sleep mode, in said receive mode, said second timing reference being switched on,
• means for determining, in said receive mode, a second channel profile of received multi-path signals,
• means for deriving a timing offset signal from a best fit obtained by fitting said first channel profiled to said second channel profile, and
• means for re-synchronizing said master timer on the basis of said derived timing offset signal;
• said communication device comprising mean-square error fitting means to perform said fitting.