Patent ID: 6694138
Filing Date: 2004-02-17
Classification: H04W

Abstract:
A method for mobile assisted handoff of a communication link between a mobile station and a base station in a digital cellular communications network, from a current base station to one of a number of candidate base stations within said network, said method comprising the steps of:generating a list of a plurality of candidate channels for possible acceptance of said communication handoff; transmitting a first measurement order from said current base station to said mobile station, said first measurement order containing said list of candidate channels; measuring a received signal strength and a bit error rate at said mobile station for said communication between said mobile station and said current base station; measuring received signal strength at said mobile station for each of said candidate channels listed in said first measurement order; transmitting said received signal strength measurements from said mobile station to said current base station; selecting a plurality of most favorable candidate channels from said received signal strength measurement results; transmitting a second measurement order from said current base station to said mobile station, said second measurement order containing a list of said most favorable candidate channels; tuning and synchronizing said mobile station to each of said candidate channels listed in said second measurement order; reading and decoding an identification code for each of said candidate channels, said step of reading and decoding including: storing data from said candidate channel into a memory device located on said mobile station; processing said data by searching for said identification code at a first predetermined number of symbols after the appearance of a probable synchronization word and, if said identification code cannot be found at said first predetermined number of symbols after said probable synchronization word, then searching for said identification code at a second predetermined number of symbols ahead of said probable synchronization word; and identifying said identification code; transmitting said identification codes for each of said candidate channels from said mobile station to said current base station; and correlating said received signal strength measurements with said identification codes to identify an optimal candidate base station for effecting said handoff of said communication.