Autonomous vehicle and control method thereof

A control method of a distributed antenna system (DAS) including a baseband modem comprises the steps of:

• calculating frequency offsets for each RF path in the baseband modem;
• controlling an oscillator clock of a central unit (CU) on the basis of an average of the frequency offsets;
• determining an operation mode of the baseband modem;
• controlling oscillator clocks of each distributed unit (DU) on the basis of the frequency offsets for each RF path when the operation mode of the baseband modem is a tracking mode;
• and
• transmitting the oscillator clock of the central unit (CU) to each distributed unit (DU) when the operation mode of the baseband modem is an acquisition mode,
• wherein, in the step of determining an operation mode of the baseband modem, upon determining that the baseband modem has performed cell search, it is determined that the operation mode of the baseband modem is the tracking mode, and upon determining that the operation mode of the baseband modem is performed before the cell search, it is determined that the operation mode of the baseband modem is the acquisition mode.

A distributed antenna system including a baseband modem and a plurality of distributed antennas comprises:

• a plurality of distributed units DU;
• and
• a central unit (CU) operatively coupled to the plurality of distributed units and to control the plurality of distributed units,
• wherein the central unit calculates frequency offsets for each RF path in the baseband modem, controls an oscillator clock of the central unit (CU) on the basis of an average of the frequency offsets, controls oscillator clocks of each distributed unit (DU) on the basis of the frequency offsets for each RF path when the operation mode of the baseband modem is a tracking mode, and transmits the oscillator clock of the central unit (CU) to each distributed unit (DU) when the operation mode of the baseband modem is an acquisition mode,
• wherein, in the tracking mode, the central unit (CU) individually controls oscillator clock errors of each distributed unit (DU) to have different values, and in the acquisition mode, the central unit (CU) commonly controls the oscillator clock errors of each distributed unit (DU) to have the same value.

An autonomous vehicle comprises:

• a processor for controlling functions of the vehicle;
• a memory coupled to the processor, for storing data for control of the vehicle;
• and
• a communication device coupled to the processor, for sending and receiving data for control of the vehicle,
• the communication device including a central unit (CU) and a plurality of distributed units operatively coupled to the central unit (CU),
• wherein the processor calculates frequency offsets for each RF path in the communication device, controls an oscillator clock of the central unit (CU) on the basis of an average of the frequency offsets, controls oscillator clocks of each distributed unit (DU) on the basis of the frequency offsets for each RF path when the operation mode of the baseband modem is a tracking mode, and transmits the oscillator clock of the central unit (CU) to each distributed unit (DU) when the operation mode of the baseband modem is an acquisition mode,
• wherein the processor individually controls oscillator clock errors of each distributed unit (DU) to have different values, and each distributed unit (DU) provides an individually controlled oscillator clock as a reference clock to the RF device of the DU, and provides a radio signal from the base station to the processor via a DU-CU interface through the RF device.