Patent ID: 8619670

Claim:
A method of controlling broadcasting for time synchronization in a wireless network, comprising: broadcasting a standard time value from an upper node to a plurality of lower nodes for a predetermined number of times per period, the standard time value being used by the plurality of lower nodes for time synchronization in the network; transmitting a time offset calculated according to the broadcast standard time value from at least some of the plurality of lower nodes to the upper node; calculating an average of the time offsets received from the at least some lower nodes, by the upper node; and resetting the number of times of broadcasting per period according to the calculated average by the upper node, by: comparing the calculated average with a predetermined average value; if the calculated average is less than the predetermined average value, decreasing the number of times of broadcasting per period, and if the calculated average is greater than the predetermined average value, the upper node resets the number of times of broadcasting to be performed to an increased number of times per period.