Patent ID: 7359356

Claim:
An overflow control method for frame synchronization in a wireless communication network system, said wireless communication network system including a radio network controller, a first base station, a second base station, and a mobile unit, wherein said radio network controller transmits a plurality of data frames to said first base station and said second base station, a first link exists between said mobile unit and said first base station, said first base station transmits received data frames to said mobile unit through said first link, said second base station includes a register for storing received data frames, said register has a storage capacity N max , said overflow control method comprising: (a) setting a judging storage capacity for said register smaller than said storage capacity N max ; (a′) determining whether a number of said plurality of data frames received by said second base station is larger than said judging storage capacity; (b) if said number of said plurality of data frames is larger than said judging storage capacity, calculating an X by subtracting said judging storage capacity from said number of said plurality of data frames; (c) deleting X of data frames from said register; (d) detecting a link quality of said first link; (e) determining whether said link quality is lower than a preset value; (f) if said link quality is lower than said preset value, calculating a CS 1 equal to a number of data frames already transmitted by said first base station to said mobile unit; (g) calculating a CS 2 equal to a number of data frames already deleted from said second base station; (h) transmitting said CS 1 to said radio network controller; (i) transmitting said CS 1 to said second base station after said CS 1 is received by said radio network controller; and (j) calculating an N by subtracting said CS 2 from said CS 1 .