KR20090043067A - Micro repeater algorithm of asynchronous auto level control - Google Patents

Abstract

The present invention relates to a repeater for a small and ultra-compact mobile communication system to prevent distortion of the uplink signal by limiting the gain of the uplink signal (the signal transmitted from the terminal to the base station) regardless of the downlink signal (the signal transmitted from the base station to the terminal). By enabling communication, it is possible to construct an algorithm that facilitates communication even if asymmetrical signal flows between downlink and uplink.

Repeater, ALC, AGC, Gain (GAIN)

Description

Micro Repeater Algorithm of Asynchronous Auto Level Control

The present invention relates to a repeater for a small and very small mobile communication system. By limiting the gain of the uplink signal irrespective of the downlink, the communication is prevented by the distortion of the uplink signal, so that the communication is smooth even when the asymmetric signal flows between the downlink and the uplink. Is to construct an algorithm that can

In the algorithm of the present invention, the AGC of the repeater for the mobile communication system adjusts the gain by using the downlink signal, but the ALC adjusts the gain by using the uplink signal, but conventionally restricts the downlink signal gain according to the uplink signal gain limit. Although there is no algorithm, through the present invention, a mobile communication relay service in a weak signal area can be smoothly obtained through a scheme for individually controlling gains of downlink signals and uplink signals according to uplink saturation.

Repeater for mobile communication system is not constant signal uplink and downlink through repeater according to its installation location and environment. The repeater is a device that transmits the RF signal of the base station to the remote area in various ways and plays back the RF signal. Since the base station antenna exists only at the center of the local cell, there is a shaded area where base station radio waves cannot reach. The purpose of the repeater is to instead reach the radio waves of the base station in this shaded area. Fundamental signal processing is performed at the base station, but repeaters are devices that deliver these signals to every corner of the shadow area.

Therefore, the repeater for a mobile communication system needs to be configured to keep the signal received from the base station and the signal transmitted from the terminal constant in consideration of non-uniform signal transmission between the base station and the terminal.

The present invention prevents the distortion of the uplink signal by limiting the gain of the uplink signal irrespective of the downlink so that the communication is prevented even if the asymmetrical signal flow between the downlink and the uplink prevents the signal distortion due to the uplink path of the repeater. The purpose is to make this smooth.

Currently, CDMA (Code Division Multiple Access) and WCDMA communication methods automatically gain the repeater equipment's gain based on the downlink signal transmitted from the base station to the terminal in the case of AGC and ALC functions in the repeater. It adjusts and prevents the saturation and distortion of the downlink signal so that the communication can be smooth.

In the case of the existing AGC and ALC algorithms, the uplink signal transmitted from the terminal to the base station adjusts the gain so as to be directly proportional to the downlink signal gain.

However, in case of small and small sized equipment applied to the weak signal area that needs a repeater, the uplink signal (the signal transmitted from the terminal to the base station) is output high, but the gain control is the downlink signal (signal transmitted from the base station to the terminal). ), The uplink signal output circuit of the equipment becomes saturated and the signal is distorted, resulting in increased communication error and loss.

However, when the downlink and uplink path of the repeater are maximized due to the low downlink input signal, the uplink signal is transmitted around the uplink signal input antenna or when the terminal outputs a high output uplink signal from the repeater with a low uplink maximum output. Communication error occurs due to the saturation phenomenon.

In this case, by limiting the gain of the uplink signal regardless of the downlink, communication is prevented by preventing distortion of the uplink signal, and the communication can be smoothed even if the asymmetric signal flows between the downlink and the uplink. It is a task.

Automatic Level Control (ALC) is a function that limits the output to a fixed level to protect the amplifier from over-input signals and prevents spurious occurrences.It determines the desired output from the repeater and compares whether the current output differs from the determined output by looping. do. In addition, AGC (Automatic Gain Control) is a device that automatically adjusts the gain so that the output is always constant even when there is a change in the input of the radio receiver or amplifier.

The AGC of the mobile communication repeater adjusts the automatic gain using the downlink signal, but the ALC adjusts the gain by using the uplink signal. However, the algorithm for limiting the gain according to the uplink signal state has not been applied. The uplink signal gain is adjusted separately from the downlink gain according to the uplink saturation so that the mobile communication relay service in the weak area can be smoothly performed.

The expected effect of the present invention is to prevent the distortion of the uplink signal by limiting the gain of the uplink signal irrespective of the change of the surrounding environment and the downlink, thereby enabling communication, and even if the asymmetric signal flows between the downlink and the uplink, the communication can be smoothed. By stabilizing so as to maximize the use efficiency of the repeater for a mobile communication system. In addition, the effect of improving the signal quality of the reverse direction and the reliability of the service can be generated to improve the call quality.

In order to reduce propagation loss and interference for base station and uplink signal for transmitting downlink signal to terminal and receiving and processing uplink signal from terminal in repeater reverse ALC function for small and small mobile communication system It is a general configuration that is installed in a certain region within the range of the base station, including a repeater for receiving the uplink signal from the terminal and transmitting to the base station.

In the present invention, the AGC of the mobile communication repeater automatically adjusts the gain using the downlink signal, but the ALC adjusts the gain by using the uplink signal, but there is no algorithm to limit the gain according to the state of the uplink signal. The proposed algorithm is to improve the downlink signal and uplink signal according to the uplink saturation state so that the mobile communication relay service in the weak area can be made smoothly. In addition, by reducing the uplink signal gain of the terminal in the downlink area, the amount of interference can be reduced in neighboring areas and the same area, thereby increasing capacity and improving quality of the system as a whole.

In the case of normal and over input of the downlink signal of FIG. 2 below, when the downlink signal of the equipment is normally relayed, the signal of the uplink terminal is also normally relayed. If the downlink input signal is high, the gain of the equipment is reduced and at the same time, the gain of the uplink signal is also reduced so that the uplink output is not saturated by the terminal signal.

When the downlink signal low input of Fig. 3 equipment has a weak downlink signal, the gain of the equipment is maximized. At this time, the output is raised to the maximum for the terminal to communicate with the base station, and the gain of the uplink path, which is correlated with the downlink path gain, is maximized, which exceeds the maximum output of the equipment, resulting in signal distortion.

In order to prevent such distortion, the newly designed algorithm as in FIG. 4 operates similarly or identically to the existing algorithm at normal and overpower. However, when the downlink is low input, the maximum gain depends on the downlink signal, but the uplink prevents distortion of the uplink output signal by variably adjusting the output according to the terminal signal.

The present invention can be easily applied to a structure using different frequency domains in the same band service or to other service providers of the same band, and to improve the capacity and quality of the system by solving the uplink signal gain problem when applying another band. have.

Figure 1. Example of wireless relay service configuration

Figure 2. In case of normal and over input of existing system downlink signal

Figure 3. Low input of existing system downlink signal

Figure 4. Existing System Downlink Signal New ALC Application Example

Claims (1)

In gain control of repeater for mobile communication system To improve communication performance by automatically adjusting the gain of the uplink so that the uplink does not saturate regardless of the downlink gain.