KR20030034906A - IS-95C Pico Base-station Transceiver Subsystem Structure - Google Patents

Abstract

PURPOSE: A micro structure of an IS-95C(Interim Standard-95C) base station is provided to implement a base station internally divided into an RF(Radio Frequency) part and a digital part with a single board in a CDMA(Code Division Multiple Access) system. CONSTITUTION: An E1/T1 interface(21) interfaces with a base station controller(12) through an E1 or T1 link, to convert ATM(Asynchronous Transfer Mode) data delivered from the base station controller(12) into PCM(Pulse Code Modulation) data. An IMA(Inverse Multiplexing for ATM)(22) converts the PCM data into UTOPIA(Universe Test and Operation PHY Interface for ATM). A CPU(23) delivers data of the base station controller(12) to an RF part(50), or converts received CDMA-demodulated data into an ATM format for delivery to the base station controller(12). A plurality of transmission DSPs(Digital Signal Processes)(25) perform FIR(Finite Impulse Response) filtering for CDMA-modulated data to pass by a phase equalizer, multiplies a gain and an IF(Intermediate Frequency) for CIC(Cascaded Integrator Comb) filtering, and adds an I-channel and a Q-channel for outputting. A DA(Digital-to-Analog) converter(26) converts digital data outputted by the transmission DSPs(25) into analog signals for delivery to the RF part(50). An AD(Analog-to-Digital) converter(27) converts analog signals from the RF part(50) into digital data. A plurality of receiving DSPs(28) perform FIR filtering for the converted digital data, and perform OPQSK(Offset Quadrature Phase Shift Keying) demodulation. A base station modem(24) performs CDMA modulation for data delivered to the RF part(50) by the CPU(23) to deliver the modulated data to the transmission DSPs(25), or performs CDMA demodulation for data delivered from the receiving DSPs(28) to deliver the demodulated data to the CPU(23). And an RF controller(29) communicates with an LPA(Linear Power Amplifier) through a UART(Universal Asynchronous Receiver/Transmitter), and collects TTL(Transistor-Transistor Logic circuit) alarms reported from the RF part(50) to report the alarms to the CPU(23).

Description

IS-95C Pico Base-station Transceiver Subsystem Structure

The present invention relates to a base station constituting a code division multiple access (CDMA) system. In particular, the digital part of a base station performing wireless access, synchronization maintenance, and call channel allocation / deletion functions of a mobile station in conjunction with a base station controller is provided as a single board. The present invention relates to a structure of an IS-95C ultra-small base station configured to enable ultra-small manufacturing.

In general, a CDMA system is composed of a mobile communication switch 11, a base station controller 12, a base station (including a repeater) 13, and a mobile station (terminal), as shown in FIG. It consists of the connection with the base station controller 12, information and authentication for the subscriber, and related additional equipment, and plays a role of establishing a connection with other networks, and the base station controller 12 includes a mobile communication exchange 11 and a base station ( 13 between the base station 13 to perform control of the base station 13, radio resource management, and soft / hard handoff functions between the base stations 13 and the base station controller 12, and the base station 13 is connected to the base station controller 12. It is matched with an E1 or T1 link, and is internally divided into a radio part (RF part) and a digital part (digital part) to perform functions such as radio access, synchronization maintenance, and call channel assignment / release of a mobile station.

The base station 13 to which the IS-95C, which is recently standardized, is applied, implements capacity increase according to the shape of the base station 13 equipment such as multi-sectorization or the expansion of the number of transmission frequencies (FA: Frequency Assignment). The structure consists of a main control unit for controlling the whole, a baseband processor for CDMA modulation and demodulation, an RF transceiver for transmitting and receiving data with the mobile station wirelessly, a line interface unit for matching with the base station controller 12, and a power supply unit. .

However, the above-described conventional IS-95C base station has a complex structure because the internal functional blocks are each composed of a single board and are implemented as a plurality of boards. There is a disadvantage that the shaded area where the cell radius does not overlap with each other occurs and the price is expensive to install in a place where the user is small.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object thereof is to provide an IS-95C micro base station structure in which a base station divided into an RF part and a digital part is internally implemented in a single board in a CDMA system.

In addition, the present invention is to implement a small base station structure of the IS-95C, to enable low-power and low-cost implementation of the base station can be easily installed at the same time.

1 is a block diagram of a general CDMA system.

2 is an internal functional block diagram of an IS-95C micro base station according to the present invention;

3 is a conceptual diagram of an output signal of a transmitting DSP implemented in an IS-95C micro base station according to the present invention;

Explanation of symbols on the main parts of the drawings

12: base station controller 20: digital part

21: E1 / T1 matching part 22: IMA

23: CPU 24: base station modem

25: transmit DSP 26: DA converter

27: AD converter 28: receiving DSP

29: RF control unit 30: repeater communication port

31: alarm signal detector 40: GPS

50: RF Part

A feature of the present invention for solving the above object is an RF part for wirelessly transmitting and receiving data to and from a mobile station through an antenna, performing a GPS reception function and a clock generation and distribution function to synchronize the entire base station and the adjacent base station. An IS-95C base station having a GPS for maintaining time synchronization with a base station, wherein the IS-95C base station processes a signal for call control and maintenance for a mobile station through the RF part and an antenna in association with a base station controller and interworks with the GPS. Accordingly, the present invention provides an IS-95C miniature base station structure including a digital part implemented as a single board for maintaining synchronization of the entire base station and time synchronization with neighboring base stations.

The digital part may include an E1 / T1 matching unit for matching the base station controller with an E1 or T1 link and converting ATM data delivered from the base station controller through the link into PCM data; An IMA for converting the PCM data converted by the E1 / T1 matching unit into UTOPIA; The base station controller data transmitted through the E1 / T1 matching unit and the IMA is transferred to the RF part side, or the CDMA demodulated data is received and converted into an ATM format and transmitted to the base station controller through the IMA and E1 / T1 matching unit. A CPU connected to the GPS and an RS422 cable to perform HDLC communication; A plurality of transmitting DSPs for performing FIR filtering of the CDMA modulated data, passing the phase equalizer, multiplying the gain and the intermediate frequency, and performing CIC filtering, and then outputting the sum of the I and Q channel signals; A DA converter converting the digital data output by the transmitting DSP into an analog signal and transferring the digital data to an RF part; An AD converter for converting an analog signal transmitted from the RF part into digital data; A plurality of receiving DSPs for performing FIR filtering on the digital data converted by the AD converter and then demodulating and transmitting the OPQSK; A base station modem for performing CDMA modulation on the data transmitted to the RF part by the CPU to the transmitting DSP, or performing CDMA demodulation on the data transmitted from the receiving DSP to the CPU; And an RF control unit communicating with the LPA through the UART, collecting the TTL alarms reported by the RF part, and reporting the collected TTL alarms to the CPU.

In addition, the digital part of the above-mentioned SS-95C base station structure includes: an alarm signal detection unit for collecting alarms generated in the base station and reporting them to the CPU; And a repeater communication port providing a port for communicating with a repeater connected to the base station.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The structure of the IS-95C micro base station to be implemented in the CDMA system according to the present invention is a digital part 20 and a radio module RF that performs most of the base station functions except RF transmission and reception, as shown in FIG. Each part 50 is configured as one board to perform the same function as the existing base station.

That is, in the present invention, the IS-95C subminiature base station controls the call to the mobile station through the RF part 50 and the antenna in conjunction with the GPS (Global Positioning System) 40 and the base station controller 12, and maintains a function. And a digital part 20 implemented as a single board to maintain synchronization of the entire base station and time synchronization with an adjacent base station in conjunction with the GPS 40, and an RF part 40 for transmitting and receiving data wirelessly with the mobile station. ) And an antenna.

The GPS 40 performs a GPS reception function and a clock generation and distribution function to maintain synchronization of the entire base station and time synchronization with an adjacent base station, and the RF part 50 finally receives the signal input from the digital part 20. The output is adjusted upward to radiate the signal through the antenna.

The digital part 20 implemented as a single board includes an E1 / T1 matching unit 21, an inverse multiplexing for ATM (IMA) 22, a central process unit (CPU) 23, and a base station modem 24. ), A plurality of transmission DSP (Digital Signal Process) 25, a DA (Digital to Analog) conversion unit 26, an AD (Analog to Digital) conversion unit 27, and a plurality of reception DSPs 28 And an RF control unit 29, a repeater communication port 30, and an alarm signal detection unit 31 as internal functional blocks.

The E1 / T1 matching unit 21 matches the base station controller 12 through the E1 or T1 link and converts ATM data delivered from the base station controller 12 through the link into pulse code modulation (PCM) data. Numeral 22 converts the PCM data converted by the E1 / T1 matching unit 21 into UTOPIA (Universal Test and Operation PHY Interface for ATM) and delivers the same to the CPU 23.

The CPU 23 receives the data of the base station controller 12 through the E1 / T1 matching unit 21 and the IMA 22 and transfers the data to the base station modem 24 or the CDMA demodulated data by the base station modem 24. Is converted into an ATM format and transmitted to the base station controller 12 through the IMA 22 and the E1 / T1 matching unit 21, and connected to the GPS 40 by an RS422 cable to perform HDLC communication.

The base station modem 24 performs CDMA modulation on the data transmitted from the CPU 23 and transmits the data to the transmission DSP 25, or CDMA demodulates the data transmitted from the reception DSP 28 to the CPU 23.

The transmit DSP 25 filters the CDMA modulated data through a finite impulse response (FIR), passes through a phase equalizer, multiplies the gain and the intermediate frequency, performs CIC filtering, and then outputs the sum of the I and Q channel signals. .

The DA converter 26 converts the digital data output by the transmission DSP 25 into an analog signal and transmits the digital data to the RF part 50. At this time, the digital data output by the transmission DSP 25 is converted into a frequency '20 MHz '. Converts to an analog signal with a bandwidth of '6.25MHz'.

Here, three transmission DSPs 25 are implemented to process one FA (Frequency Assignment) signal, respectively, and can be changed to an arbitrary frequency by changing the DSP program, and the three signals are summed through the DA converter 26. Output to RF part 50.

The RF part 50 may upwardly adjust a signal output from the transmission DSP 25 of the digital part 20 through the DA converter 26 to a final output, that is, an RF signal, and may be received by the mobile station through an antenna. When the RF signal is received through the antenna, it is adjusted down to have a frequency of '70 MHz 'and a bandwidth of' 6.25 MHz 'to transmit the corresponding analog signal to the AD converter 27 of the digital part 20. .

The AD converter 27 converts the analog signal transmitted from the RF part 50 into digital data and transmits the digital signal to the reception DSP 28, and the reception DSP 28 converts the digital data converted by the AD converter 27. FIR filtering and demodulates the offset quadrature phase shift keying (OPQSK) to the base station modem (24).

Here, three reception DSPs 28 are implemented to process one FA (Frequency Assignment) signal generated by adding three FA signals in an RF part, and may be changed to an arbitrary frequency by changing a DSP program.

The RF control unit 29 communicates with a linear power amplifier (LPA) through a universal asynchronous receiver / transmitter (UART), collects all the transistor-transistor logic circuit (TTL) alarms reported by the RF part 50, and executes a CPU (23). Report).

The repeater communication port 30 provides a port for communicating with a repeater connected to the micro base station, and the alarm signal detecting unit 31 provides an alarm (for example, fire, humidity, temperature, flooding, door opening) related to the micro base station. Door open) and the like, and report the result to the CPU 23.

On the other hand, in the IS-95C ultra-compact base station according to the present invention, the RF part 50 is a filter that can accept up to seven FA signals output by the transmission DSP 25 as shown in FIG. In this case, the transmission DSP 25 implemented in the digital part 20 may output the separated FA signal by arbitrarily arranging three FA signals as shown in (b) of FIG. 3.

Receiving and processing a signal through an antenna is a concept opposite to the above-described transmission processing. The RF part 50 transmits three FA signals synchronized with a transmission clock to the reception DSP 28, and the reception DSP 28 By using the separate FA signal by setting each FA signal transmitted from the RF part 50 to the frequency, it can appropriately respond to the base station installation request of the service provider.

Referring to the operation of the IS-95C micro base station according to the present invention configured as described above are as follows.

First, when ATM data is input from the base station controller 12 to the micro base station through the E1 / T1 link, the E1 / T1 matching unit 21 of the micro base station converts the ATM data input from the base station controller 12 into PCM data. After that, it is delivered to the IMA 22.

Then, the IMA 22 converts the PCM data transmitted from the E1 / T1 matching unit 21 to UTOPIA and delivers the data to the CPU 23. The CPU 23 transfers the data transmitted from the IMA 22, namely, The data transmitted from the base station controller 12 is transferred to the base station modem 24.

Accordingly, when the base station modem 24 transmits the CDMA modulated data transmitted from the CPU 23 to the transmitting DSP 25, the transmitting DSP 25 performs FIR filtering on the CDMA modulated data. Pass through the phase equalizer, multiply the gain, multiply it by the intermediate frequency, perform CIC filtering, and then combine the I and Q channel signals to convert them into analog signals through the DA converter 26 to the RF part 50. Will print.

In this case, in the RF part 50, the transmission DSP 25 of the digital part 20 adjusts the signal output through the DA converter 26 to the RF signal to be finally output and radiates it through the antenna.

On the contrary, when the RF signal is input to the micro base station through the antenna, the RF part 50 of the micro base station adjusts the frequency of the RF signal downward and transmits it to the reception DSP 28 side of the digital part 20. The AD converter 27 implemented at the front end of the DSP 28 converts the analog signal transmitted from the RF part 50 into digital data and delivers it to the receiving DSP 28.

Then, the reception DSP 28 performs FIR filtering on the input data, which is converted into digital data by the AD converter 27, performs OPQSK demodulation, and then CDMA demodulates the data through the base station modem 24 to the CPU 23. In this case, the CPU 23 converts the CDMA demodulated data by the base station modem 24 into the ATM format and transmits the data to the base station controller 12 through the IMA 22 and the E1 / T1 matching unit 21. .

Meanwhile, in the present invention, the digital part and the RF part of the base station applied to the IS-95C are configured as a single board, respectively, to perform the same function as the conventional one, thereby simplifying the structure of the base station and making a very small base station possible.

In addition, the embodiments according to the present invention are not limited to the above-described embodiments, and various alternatives, modifications, and changes can be made within the scope apparent to those skilled in the art.

As described above, the present invention implements a base station divided into an RF part and a digital part internally in a CDMA system as a single board, thereby simplifying the structure, making it possible to manufacture a small size of the IS-95C base station, and at the same time, to implement a low power and low cost. It becomes possible and the installation of the base station becomes easy.

Claims (3)

An IS-95C base station having an RF part for transmitting and receiving data wirelessly with a mobile station through an antenna, and a GPS for maintaining synchronization of the entire base station and time synchronization with an adjacent base station. Interworking with the base station controller, the RF part and antenna process signals for call control and maintenance for the mobile station, and interworking with the GPS, it is implemented as a single board to maintain synchronization of the entire base station and time synchronization with the adjacent base station. The IS-95 microminiature base station structure characterized by including the digital part. The digital part includes: an E1 / T1 matching unit for matching with a base station controller through an E1 or T1 link and converting ATM data delivered from the base station controller through the link into PCM data; An IMA for converting the PCM data converted by the E1 / T1 matching unit into UTOPIA; Delivers the data of the base station controller delivered through the E1 / T1 matcher and the IMA to the RF part side, receives the CDMA demodulated data, converts the data into an ATM format, and transmits the data to the base station controller through the IMA and E1 / T1 matchers. CPU; A plurality of transmit DSPs which FIR filter the CDMA modulated data, pass through a phase equalizer, multiply the gain and the intermediate frequency, and CIC filter the multiplied gain and intermediate frequencies and then output the sum of the I and Q channel signals; A DA converter converting the digital data output by the transmitting DSP into an analog signal and transferring the digital data to an RF part; An AD converter for converting an analog signal transmitted from the RF part into digital data; A plurality of receiving DSPs for performing FIR filtering on the digital data converted by the AD converter and then demodulating and transmitting the OPQSK; A base station modem for performing CDMA modulation on the data transmitted to the RF part by the CPU to the transmitting DSP, or performing CDMA demodulation on the data transmitted from the receiving DSP to the CPU; And an RF control unit for communicating with the LPA through a UART, and collecting and reporting the TTL alarm reported by the RF part to the CPU. The method of claim 2, An alarm signal detector for collecting alarms generated from a base station and reporting the alarms to the CPU; RS-95C micro base station structure further comprises a repeater communication port providing a port for communicating with a repeater connected to the base station.