Abstract: Provided is a data communication system including a first-in first-out (FIFO) buffer having a fixed size; a central processing unit (CPU) that writes data stored in a memory into the FIFO buffer; a modem that reads the data written by the CPU from the FIFO buffer; and a modem controller that is connected to the FIFO buffer, the CPU, and the modem, respectively, and controls the CPU such that data having a larger volume than the size of the FIFO buffer can be processed.

Abstract: There are provided a system on chip (SoC) with a low power mode and a method of driving the SoC, the SoC including: a power part supplying a main clock signal and controlling analog and digital power supply at a normal mode and supplying a sub clock signal and turning analog power off at a low power mode; a radio frequency (RF) part generating the main clock signal at the normal mode and stopping operation at the low power mode, under the control of the power part; and a control part operating according to the main clock signal at the normal mode and operating according to the sub clock signal, under to the control of the power part.

Abstract: Provided is a synchronization device for wireless communication packets, the synchronization device including an A/D (analog/digital) converter that converts an analog input signal applied from outside into a digital signal; a correlation calculating section that is connected to the A/D converter and correlates the converted input signal with a preset reference code so as to calculate a correlation value; a threshold setting section that is connected to the correlation calculating section and sets a threshold value of the correlation value; a maximum correlation detecting section that is connected to the correlation calculating section and the threshold setting section, compares the correlation value with the threshold value, detects the position of the maximum correlation value within each symbol of the input signal when the correlation value is larger than the threshold value, and judges whether a difference in position between the maximum correlation values of consecutive symbols is equal to the period of

Abstract: A data transmission method indicating data pending in a ZigBee network is provided, wherein the data transmission method is used to shorten a delay time for data transmission by setting a certain bit to indicate data pending in the ZigBee network to a ZigBee device, the certain bit indicating data pending to an acknowledge frame for acknowledging a data frame from the ZigBee device. The data transmission method according to the present invention includes broadcasting beacons so as to allow the ZigBee coordinator to maintain the connection of the ZigBee network; downloading a data frame from an assigned ZigBee device transmitting the data frame by receiving the beacons; and transmitting an acknowledge frame including a data pending bit indicating data pending to the assigned ZigBee device.