Wireless base station with internal clock correction
A wireless base station that performs wireless communication with a mobile terminal is connected to a plurality of time information notification servers. The wireless base station selects any of a plurality of pieces of time information notified from a plurality of time information notification servers, respectively, and corrects an internal clock based on the selected piece of time information. This can keep the internal clock of the wireless base station highly accurate.
1. A wireless base station connected to a plurality of time information notification servers and performing wireless communication, said wireless base station comprising:
a time information selection section selecting any of a plurality of pieces of time information notified from said plurality of time information notification servers, respectively;
a clock correction section correcting an internal clock based on said selected piece of time information; and
a malfunction detection section detecting a malfunction of said plurality of time information notification servers, wherein
said malfunction detection section detects a malfunction of said time information notification servers by comparing a count value obtained by measuring an interval of pulses transmitted from said time information notification servers with a predetermined threshold value,
said time information selection section excludes, from options, the piece of time information notified from the time information notification server of which a malfunction is detected by said malfunction detection section.
2. The wireless base station according to claim 1 , further comprising a time accuracy identification section identifying the accuracy of each of said plurality of pieces of time information notified from said plurality of time information notification servers, respectively, wherein
said time information selection section selects the piece of time information based on a result of the identification made by said time accuracy identification section.
3. The wireless base station according to claim 2 , wherein
said time accuracy identification section identifies the accuracy of said plurality of pieces of time information by using, as a reference, the frequency of said internal clock in which a frequency error due to start-up characteristics of an oscillator of said internal clock has been corrected.
4. The wireless base station according to claim 1 , wherein
a process other than a process for correcting said internal clock is stopped at regular intervals such that said process for correcting said internal clock can be performed in a certain cycle.
5. The wireless base station according to claim 4 , wherein
said process for correcting said internal clock includes a task for writing a counter value for internal clock correction.
6. The wireless base station according to claim 1 , wherein
said clock correction section comprises means for determining whether or not a particular process is being performed, and does not correct said internal clock while said particular process is being performed.
7. The wireless base station according to claim 6 , wherein
said particular process includes a demodulation process for demodulating reception data.