KR20000030537A - Apparatus and Method for controlling a gain of link in communication system - Google Patents

Abstract

PURPOSE: A device for control the link gain of communication system is provided to improve the quality of communication service as detecting the transition of total gain by link loss and controlling automatically. CONSTITUTION: The device for control the link gain of communication system comprises 1) the means happening verification signal trnsmitted along communication line and minimizing the quality of communication signal, 2) the means combining with signal which overlaps the occurred verification signal with communication signal and transmits,3) the means detecting the detection signal, 4) the control means outputting the signal decay rate of communication line by the strength of proving signal.

Description

Apparatus and Method for controlling a gain of link in communication system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for controlling a link gain of a communication system, and more particularly, to a remote antenna unit (RAU) and a transmission / reception interface device (RAU) in a microcell or picocell system including an analog relay device for wireless communication. An apparatus and method for stabilizing reverse link gain between a transceiver interface unit (TIU) are provided.

1 is an example of a configuration of an analog relay device of a conventional wireless communication system, which is connected to a base station transceiver subsystem (BTS) 10 and relays transmission and reception signals of the base station apparatus 10. A Transceiver Interface Unit (TIU) 20; And a remote antenna unit (RAU: Remote Antenna Unit) (RAU) that is connected to the TIU 20 in a wired (or wireless) manner and is responsible for a communication interface between the TIU 20 and a wireless terminal (not shown). have.

FIG. 2 is a detailed configuration diagram of the RAU 30 shown in FIG. 1. The link interface (LI) 31 in charge of a communication interface between the TIU 20 and the wired / wireless link serving as a connection medium is shown. ); A forward drive amplifier (FDA) 32 for amplifying a forward signal input through the LI 31; A forward link attenuator (F_ATT) 33 for attenuating the amplified forward signal; A high power amplifier (HPA) 34 or a linear power amplifier (LPA) for proportionally amplifying the attenuated forward signal in a given service band and outputting a high frequency (RF) signal through an antenna (Ant.) ; A low noise amplifier (LNA) 35 for low noise amplifying a reverse signal received through the antenna Ant; A reverse attenuator (R_ATT) 36 for attenuating the low noise amplified reverse signal; A reverse drive amplifier (RDA) 37 for amplifying the attenuated reverse signal and applying it to the LI 31 at an appropriate value; A common connection between the HPA 34, the LNA 35, and the antenna Att. Comprises a duplexer 38 for transmitting and receiving separation of the forward and reverse signals and proper filtering.

1 and 2, in the conventional wireless communication system, a relay device proposed in various forms such as a wireless link or a wired link in order to economically secure service coverage of the parent base station apparatus 10. (Including a micro cell device) is used.

In the relay apparatus of FIG. 1, the link interface transmits a radio frequency (RF) signal or a radio / intermediate frequency (RF / IF) signal in an analog manner, between the RAU 30 and the TIU 20. The loss value of the wireless or wired link of the system varies depending on the situation, especially the loss of the reverse link (RAU to TIU link) (including losses caused by each device) that changes with temperature, humidity, weather, etc. It causes a deterioration in quality.

In more detail, in the case of the forward link, the HPA 34 of the RAU 30 typically outputs an output level sensing circuit because a stable constant level of output value is required to ensure the reliability of service within a given coverage. (Not shown) and using the FDA 32 and the F_ATT 33 to achieve a stable output level. Therefore, if the change of the output level is detected and there is a change over a certain level, the change value can be predicted as the loss value of the link including the loss of each device, and appropriate measures can be taken. Since the level of U varies significantly depending on time, place, and the like, there is a problem that a change in signal level cannot be predicted as a link loss, as in the case of the forward link described above.

In conclusion, when the link loss between the RAU 30 and the TIU 20 increases in the reverse direction, the noise figure (NF) of the reverse link is increased, and the RAU is increased due to an increase in operating temperature. When the gain value of the reverse circuit provided in (30), that is, the LNA 35, the R_ATT 36, and the RDA 37 decreases, the noise figure of the entire reverse link is increased and the gain value decreases. The BTS 10 increases the output level of the terminal more than necessary. As a result, such an effect has a problem of causing a decrease in service availability within a given coverage, but there is currently no countermeasure against reverse link loss.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object thereof is to stabilize a gain by detecting and compensating for a loss of a link in a structure of a microcell / picocell for wireless communication and a relay remote antenna. It is an object of the present invention to provide an apparatus and method for controlling a link gain of a wireless communication system that detects, corrects and stabilizes a total gain change due to loss of a link and a reverse circuit element in a reverse direction.

1 is a block diagram of an analog relay device of a conventional wireless communication system,

2 is a detailed configuration diagram of the remote antenna device (RAU) of FIG.

3 is a block diagram of an apparatus for controlling a link gain of a wireless communication system according to the present invention;

4 is a diagram illustrating an embodiment in which the present invention of FIG. 3 is applied to an analog relay apparatus of the conventional wireless communication system of FIG. 1.

5 is a flowchart of a link gain control method of a wireless communication system according to the present invention;

6 is a view showing a CDMA carrier influence analysis according to the offset frequency input in the apparatus of the present invention,

FIG. 7 is a diagram illustrating a reverse link gain control procedure according to an embodiment of FIG. 5.

※ Explanation of code for main part of drawing

10: base station unit (BTS) 40: remote antenna unit (RAU)

41: tone generator (TG) 42: first switch (S / W)

43a, 43b: signal combiner 44: first controller

50: transmit / receive signal interface device (TIU)

51a, 51b: signal detector 52: second switch

53: tone signal strength measuring instrument (TSSM) 54: second controller

In order to achieve the above object, a link gain control apparatus of a wireless communication system according to the present invention is a signal for generating a signal that can be transmitted along a communication line while minimizing an influence on the quality of a communication signal in a wireless communication system. Generating means; Signal combining means for transmitting the generated signal to the communication line by overlapping a communication signal; Detection means for detecting a signal of said signal transmission means superimposed and transmitted; And control means for calculating a signal attenuation rate or gain of the corresponding communication line based on the detected signal strength, wherein the communication line is a wired or free space wireless link including an optical fiber. It features.

In order to achieve the above object, in the link gain control method of the wireless communication system according to the present invention, a signal having a predetermined strength according to a value set in communicating signals between a transmitting side and a receiving side of the wireless communication system is provided. A first step of coupling to a transmission signal and transmitting through a communication line; A second step of detecting the verification signal by receiving the transmitted combined signal; A third step of calculating a signal attenuation rate of the communication line by comparing the detected verification signal strength with the set strength; And a fourth step of controlling a gain of a corresponding communication line based on the signal attenuation rate or performing an alarm for fault recovery, wherein the verification signal is relatively compared to a transmission bandwidth of a communication signal transmitted along the communication line. Characterized in having a narrow bandwidth, characterized in that present in the transmission band of the communication signal, the communication signal is composed of a plurality of carrier signals accompanying the traffic signal, the communication signal transmission band is the RAU It is characterized in that the same or wider than the bandwidth of the radio frequency (RF) signal to support.

The signal coupling means and the signal detecting means are respectively provided at both ends (transmitting and receiving end) of the communication path where the concentrated loss occurs by the apparatus and method of the present invention, and the other constituent means are organic based on the above description. By comparing the quantum strength at the time of transmission and the detection of the verification signal, the loss due to the circuit element and the link installed in the section can be estimated, and the loss can be compensated based on the prediction. In particular, by detecting the amount of attenuation of the entire signal due to the link loss, including the loss of the circuit element in the reverse direction pointed out as a conventional problem, and controlling the gain of the line, it is possible to compensate the loss of the line.

Hereinafter, an apparatus and method for controlling a link gain of a wireless communication system according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram of an apparatus for controlling a link gain of a wireless communication system according to an embodiment of the present invention, wherein a tone generator (TG) generating a tone signal having a predetermined intensity according to a set value is provided. 41); A first switch 42 for switching the output path of the generated tone signal; A plurality of signal couplers (43a, 43b) respectively installed on a plurality of communication signal transmission side paths and connected to the switch (42) for combining and outputting the switched tone signal and the communication signal; A first controller (44) for controlling signal generation of the tone generator (41) and path switching operation of the first switch (42); A plurality of signal detectors (51a, 51b) provided on the plurality of receiving side paths corresponding to the plurality of transmitting side paths to detect the tone signal among the received signals; A second switch 52 for selecting one of the detected signals; A tone signal strength measurement (TSSM) 53 for measuring the intensity of the detected selected tone signal; And comparing the measured intensity of the tone signal with the strength of the tone signal set in the tone generator 41 to obtain a corresponding line attenuation amount (or link gain change amount), and based on the attenuation amount (or change amount). And a second controller 54 for controlling the link gain. The first switch 42 and the second switch 52 are necessary to reduce the number of TG and TSSM. Therefore, if there is only one path to be measured or if TG and TSSM are provided for each path to be measured, these switches are unnecessary, but in the latter case, economics may be a problem. The second controller 54 can directly or indirectly correct the link gain change, and can implement a function as a signal divider instead of the first switch and the second switch.

FIG. 4 is an embodiment in which the present invention of FIG. 3 is applied to an analog relay apparatus of the conventional wireless communication system of FIG. 1, and the same components as in FIGS. 1 and 3 will be described with the same reference numerals.

In FIG. 4, the RAU 40 further includes the transmitter-side circuit of FIG. 3 in addition to the RAU 30 configuration of FIG. 2. The duplexer 38, the LNA 35, the R_ATT 36, and the RDA are shown in FIG. A signal combiner 43a is connected between the duplexer 38 and the LNA 35 in a reverse primary path that passes sequentially through the 37, and a diversity path of the reverse link. The band filter 45 in the reverse diversity path which in turn passes through a band filter 45 (RX filter) 45, a LNA 35 ', an R_ATT 36', and a RAD 37 'for band-receiving a backward reception signal. ) And another signal coupler 43b is installed between the LNA 35 'and the first switch 42, the tone generator 41, and the first controller 44 in other configurations. The configuration and connection of the lights are the same as in FIG. 3. In addition, the FDA 32, the F_ATT 33, and the HPA 34 constitute the forward circuit unit 46 of the RAU 40, and the LNA 35, 35 ′, R_ATT 36, 36. ') And RDAs 37, 37' constitute reverse circuitry 47 of the primary and diversity paths of RAU 40, respectively.

4 again, the TIU 50 includes a forward circuit portion 56, a reverse circuit portion 57, and a reverse circuit portion 46, corresponding to the forward circuit portion 46, the reverse circuit portion 47, and the link interface 31 of the RAU 40, respectively. And a link interface 55, wherein the forward circuit portion 56 of the TIU 50 forward-amplifies a forward output amplifier (FIA) 61 for amplifying the forward output signal of the BTS 10. And a forward attenuator (F_ATT) 62 that attenuates the amplified signal.

The reverse circuit 57 is a reverse interface amplifier (RIA) 63 and 63 'for amplifying a reverse signal received through the link interface 55 to correct a signal loss value for the link. A reverse attenuator (R_ATT) 64, 64 'that attenuates the amplified reverse signal and provides it to the BTS 10, wherein the RIA (63,63') and the R_ATT (64,64 ') are primary. It is installed for the Primary path and the Diversity path respectively. The configuration of the TIU 50 described above is the same configuration as the existing TIU 20, and the gist configuration of the present invention added thereto is as follows.

The receiving circuit of FIG. 3 according to the present invention is provided in the reverse circuit unit 57 of the TIU 50. Referring to FIG. 4, the signal detector (A) is output at the output terminal of each of the R_ATTs 64 and 64 '. 51a and 51b are connected, and other components of the second switch 52, the TSSM 53, the second controller 54, and the like are the same as in FIG.

FIG. 5 is a flowchart illustrating a link gain control method of a wireless communication system according to the present invention. First, in a signal communication between a transmitting side and a receiving side of a wireless communication system, a verification signal having a predetermined intensity (pulse, A tone or a modulated signal) is coupled to a transmission signal and transmitted through a communication line (S1), and the received signal is detected to detect the verification signal (S2), and then the strength and the setting of the detected verification signal Comparing the strength of the verification signal, the difference value is obtained, and the signal attenuation rate of the communication line is calculated based on the difference value (S3). Finally, the gain of the corresponding call line is controlled based on the calculated signal attenuation rate. Or loss of link (e.g. RAU to TIU link) due to temperature change, humidity change, weather, etc. The loss due to the correction of included) so as to improve the call quality (S4).

Next, a description of the link gain control method of the wireless communication system according to an embodiment of the present invention will be described in detail with the description of the operation of the apparatus of FIG. 4.

First, by the control of the first controller 44 provided in the RAU 40, the tone generator 41 generates a tone signal having a predetermined intensity, and according to the control of the first controller 44. The tone signal generated by the selective switching operation of the first switch 42 is selectively transmitted to the signal combiner 43a of the primary path or the signal combiner 43b of the diversity path. Each signal combiner 43a or 43b couples the tone signal to a corresponding reverse signal (i.e., a reverse primary signal or a reverse diversity signal), and the combined signal is a corresponding path (35 → 36 → 37 or 35). '36' → 37 ') and the link interface 31 to the TIU 50 (S1).

The transmitted combined signal is received via the link interface 55 of the TIU 50, and only the tone signal is detected by the signal detector 51a or 51b installed in the corresponding path (S2), and the detected tone signal. Is input to the TSSM 53 through a third switch 52. The TSSM 53 measures the intensity of the detected tone signal, and the second controller 54 compares the intensity of the measured tone signal with the intensity of the tone signal set in the tone generator 41. Obtain the signal attenuation rate (the reverse link loss including the loss of each reverse circuit element between the signal combiner 43a or 43b and the signal detector 51a or 51b) corresponding to the difference value (S3), and Based on the signal attenuation rate, the attenuation rate of the R_ATT (36, 36 'or 64, 64') installed in the corresponding communication signal path is controlled directly or indirectly to compensate for the gain loss of the corresponding link including the loss of reverse circuitry. S4). R_ATT may be digital or analog, and the gain change of the link may be corrected using an AGC amplifier capable of automatic gain control instead of the amplifier and R_ATT.

As can be seen from the above description, the coupling point of the tone signal and the corresponding reverse signal can be changed according to the installation position of the signal combiner 43a or 43b, and the combined transmission according to the installation position of the signal detector 51a or 51b. Since the detection point of the received tone signal can be changed, the signal combiner 43a or 43b and the signal detector 51a or 51b are provided in a desired concentrated loss section, so that the signal due to deterioration of the line or each element located in the section is provided. The loss can be detected.

The TG 41 allows the output level of the tone signal to be constant (within 1 dB) without being affected by changes in temperature, etc., and allows the operator to adjust the output value of the tone signal during initial installation or operation. The intensity of the received tone signal is recorded and stored in the first and second controllers 54 as well. If the output level changes depending on the operating temperature, an operating temperature band output level table can be used.

In addition, when applying the present invention to a code division multiple access (CDMA) system, the frequency of the tone signal is an appropriate offset value at the center frequency of the CDMA signal (e.g., a bandwidth of 1.23 MHz in the IS-95 CDMA system). It is preferable to have a, because the tone signal is to minimize the influence on the quality of the communication signal even if the tone signal and the communication signal is transmitted by the signal combiner (43a, 43b) combined. That is, as shown in FIG. 6, in the CDMA system transmitting only one CDMA carrier, if the desired signal band is filtered using a SAW filter, the offset value may be set at about 600KHz to 800KHz, and about + 700KHz may be appropriate. Since this offset value can reduce the influence of more than 15 dB than other frequencies and the signal is not damaged by the SAW filter significantly, considering the variation of the received signal received through the antenna (Ant.) Of the RAU 40, It is most appropriate to set the offset value of the tone signal to +700 KHz. In case of transmitting several CDMA carriers, it is preferable that this tone signal frequency is located at the center of the center frequency of adjacent CDMA carriers (offset frequency = + or-(carrier bandwidth) / (2) MHz). In addition, tones such as tone signals generated in TG that are within the transmission bandwidth (including those within the communication signal transmission band and not used for service or other service providers) without affecting the communication signal quality. A verification signal that plays a role can also be used.

Next, a link gain control method for stabilizing a reverse link gain using a link gain control apparatus of a wireless communication system according to the present invention will be described separately in the case of initial installation and in operation of the apparatus according to the present invention. .

First, in the case of the initial installation, the installer generates and outputs the tone generator 41 manually at the site where the RAU 40 is installed or by the control of the first controller 44 connected to the TIU 50. The intensity of the tone signal is adjusted to a predetermined level, and the tone signal of a predetermined size is transmitted through the signal combiners 43a and 43b in the reverse primary or diversity signal path. The TIU 50 detects the tone signal transmitted by being coupled to the primary signal or diversity signal through signal detectors 51a and 51b, and obtains the strength of the tone signal detected through the TSSM 53. The second controller 54 compares each of the circuits between the signal combiner 43a and 43b and the signal detectors 51a and 51b by comparing the intensity of the initially set tone signal with the intensity of the detected tone signal. A link loss including a loss due to device degradation is predicted and compensated for directly or indirectly.

Next, the case of operation is demonstrated with reference to FIG.

First, when multiple RAUs are connected to the TIU, the TIU commands RAU # 1 to combine the tone signals in the primary path (101). The RAU # 1 receives a TIU command and transmits a tone signal set to a predetermined size in combination with a primary signal path, and the TIU receives the transmitted signal to detect a tone signal, and detects the tone signal strength and the setting. The link gain change value is checked by comparing the intensity of the tone signal. The diversity path is then checked in the same manner as described above (103 to 104). In the same manner as in steps 101 to 104, the link gain change value between RAU # 2 and TIU is checked (105-108) with a predetermined period sequentially, and then measured up to RAU # N (109-112). Here, when a check request for RAU # 2 is received by the command 113 from the Operation Maintenance Center (OMC) in a specific period, the link gain change is sequentially checked for the RAU # 2 as described above (114 to 117). ). The checked data is transmitted 118 to the OMC. After that, it is polled from RAU # 1 again in order.

As described above, if the link loss value between the TIU and each RAU is checked a plurality of times, and there is a change in the intensity of the tone signal for the corresponding reverse link (including the inter-link circuitry) based on the check, based on the change value The gain value corresponding to the link loss is corrected. As an example of the gain correction method, the reverse attenuators 64 and 64 'included in the TIU 50 of FIG. 4 or the reverse interrupter 36 provided in the RIU are provided. Lowering the attenuation rate of 36 'through the second controller 54 or indirectly through the first controller 44 to compensate for the corresponding reverse link loss.

As described in detail above, the apparatus and method for controlling a link gain of a wireless communication system according to the present invention improves the quality of a communication signal by detecting a gain change in a communication signal path and compensating for a changed gain value, in particular, such as a wireless CDMA. In the reverse path where the level of the received signal in the communication relay device changes drastically, the overall gain change due to the link loss including the loss of the reverse circuit element is accurately detected and automatically controlled and stabilized, thereby improving the communication service quality. have,

Claims (9)

In a wireless communication system, Signal generating means for generating a verification signal that can be transmitted along the communication line with a minimal effect on the quality of the communication signal; Signal combining means for transmitting the generated verification signal to the communication line and overlapping the communication signal; Detecting means for detecting a verification signal of the superimposed transmitted signal generating means; And And control means for calculating a signal attenuation rate of a corresponding communication line based on the detected verification signal strength. The method of claim 1, The verification signal generated by the signal generating means includes a pulse signal, a tone of a predetermined frequency, or a modulation signal, and has a relatively narrow bandwidth compared to the transmission bandwidth of the communication signal and transmits the communication signal. Link gain control device of a communication system, characterized in that present in the band. The method of claim 1, And said communication line comprises a wired and a wireless link comprising an optical fiber. In a wireless communication system for transmitting and receiving a communication signal having a plurality of communication lines, Tone generating means for generating a tone signal of a predetermined intensity according to a value set; First switching means for switching an output path of the generated tone signal; A plurality of signal combining means respectively installed on a plurality of reverse paths of the reverse transmitting end of the communication signal and connected to the first switching means to combine and output the switched tone signal and the communication signal; First control means for controlling signal generation of the tone generating means and path switching of the first switching means; A plurality of signal detecting means for detecting the tone signal among signals received and installed on a plurality of receiving end paths corresponding to the reverse transmitting end; Second switching means for selecting one of the detected signals; Tone signal strength measuring means for measuring the intensity of the detected selected tone signal; And And a second control means for comparing the measured intensity of the tone signal with the intensity of the tone signal set in the tone generating means to obtain a line attenuation amount and to control the link gain of the corresponding communication signal line based on the attenuation amount. Link gain control device of a communication system, characterized in that. In mutually communicating signals between a transmitting side and a receiving side of a wireless communication system, A first step of coupling a verification signal having a predetermined strength according to a value to be set to a communication signal and transmitting the same through a communication line; A second step of detecting the verification signal by receiving the transmitted combined signal; A third step of calculating a signal attenuation rate of the communication line by comparing the detected verification signal strength with the set strength; And And a fourth step of controlling a gain of a corresponding communication line based on the signal attenuation rate or generating an alarm for fault recovery. The method of claim 5, The verification signal has a relatively narrow bandwidth compared to the transmission bandwidth of the communication signal transmitted along the communication line, the link gain control method of a communication system, characterized in that located in the communication signal transmission frequency band. The method of claim 5, The verification signal, when the communication signal is a single carrier signal according to a code division multiple access communication method, has a predetermined frequency spaced apart from the center frequency of the communication signal by about 600 KHz to 800 KHz. A link gain control method for a communication system, wherein the frequency is located near the center between carrier center frequencies. The method according to claim 5, 6 or 7, And said verify signal is a pulse, tone or modulated signal. The method of claim 5, Wherein the first step is transmitted while changing the coupling point of the verification signal, and the second step is detected by changing the detection point of the verification signal.