Analog distributed antenna system and its operating method
Some embodiments of the present disclosure relate to an analog distributed antenna system, and its operating method, provided with an orthogonal frequency division multiplexing (OFDM) high-speed modem for use in transceiving control signals between a main unit and remote units in order to effectively control the remote units connected to the main unit.
1. A main unit of an analog distributed antenna system, the main unit comprising:
an interface unit configured to receive a radio signal input from a base station;
a control unit configured to generate a control signal for controlling at least one remote unit connected to the main unit;
a power line communication (PLC) modem configured to modulate the control signal based on an orthogonal frequency division multiplexing (OFDM) scheme to output an analog RF signal in a frequency range of 1 to 30 MHz;
a signal coupler configured to generate a combined signal from the radio signal and the analog RF signal; and
an optical transceiver configured to convert the combined signal to an optical signal and transmit a converted optical signal to the remote unit.
2. The main unit of claim 1 , which is configured to support Ethernet-based Internet protocol (IP) communications with unique IP addresses assigned to respective components of the main unit, and
wherein the control unit is configured to transmit the control signal in the form of an Ethernet protocol to the PLC modem based on a scheme of the Ethernet-based IP communications.
3. A remote unit of an analog distributed antenna system, the remote unit comprising:
an optical transceiver configured to receive an optical signal transmitted from a main unit, and convert the optical signal into an analog signal as an output;
an interface unit configured to analyze the analog signal, classify a control signal band including a control signal for the remote unit and a communication signal band including a radio signal transmitted from a base station, and output, through different output channels, band signals of the respective classified bands;
a power line communication (PLC) modem configured to receive a signal in a frequency range of 1 to 30 MHz, corresponding to the control signal band included in the analog signal, and extract the control signal in the form of an Ethernet protocol from the signal in the frequency range; and
a control unit configured to control the operation of respective components of the remote unit based on the control signal.
4. The remote unit of claim 3 , which is configured to support Ethernet-based Internet protocol (IP) communications with a unique IP address assigned based on an IP address which is interlocked with the remote unit and assigned to a component of the main unit.
5. An analog distributed antenna system, comprising:
a main unit configured to relay a radio signal between a base station and a plurality of remote units installed in a service area, and when relaying the radio signal, convert a control signal for controlling the remote units to an RF signal, combine the RF signal and the radio signal into a combined signal and optically transmit the combined signal to the remote units; and
one or more of the remote units configured to receive the optically transmitted signal from the main unit, convert the received optical signal into an analog signal, and analyze the analog signal to transmit the radio signal included in the analog signal to a corresponding user terminal and to operate the remote unit based on the control signal included in the analog signal,
wherein the main unit comprises a first power line communication (PLC) modem configured to modulate the control signal based on an orthogonal frequency division multiplexing (OFDM) scheme to output the RF signal in a frequency range of 1 to 30 MHz.
6. The analog distributed antenna system of claim 5 , wherein the components of the main unit and the one or more of the remote units are respectively assigned unique IP addresses to support Ethernet-based Internet protocol (IP) communications.
7. The analog distributed antenna system of claim 5 , wherein the remote unit comprises:
a second power line communication (PLC) modem configured to receive a signal in a frequency range of 1 to 30 MHz, corresponding to the control signal included in the analog signal, and extract the control signal in the form of an Ethernet protocol from the signal in the frequency range.
8. A method for operating a main unit of an analog distributed antenna system, the method comprising:
receiving a radio signal input from a base station;
generating a control signal for controlling at least one remote unit connected to the main unit;
by using a power line communication modem, modulate the control signal based on an orthogonal frequency division multiplexing (OFDM) scheme to output an analog RF signal in a frequency range of 1 to 30 MHz;
generating a combined signal from the radio signal and the analog RF signal; and
converting the combined signal to an optical signal and transmitting a converted optical signal to the remote unit.
9. A method for operating a remote unit of an analog distributed antenna system, the method comprising:
receiving an optical signal transmitted from a main unit, and converting the optical signal into an analog signal as an output;
analyzing the analog signal, classifying the analog signal between a control signal band including a control signal for the remote unit and a communication signal band including a radio signal transmitted from a base station, and outputting, through different output channels, band signals of the respective classified bands;
by using a power line communication modem, extracting the control signal in the form of an Ethernet protocol from a signal in a frequency range of 1 to 30 MHz, the signal in the frequency range corresponding to the control signal band included in the analog signal; and
operating the remote unit based on the control signal.