KR19990004296A - Frequency conversion mobile telephone repeater and its operation method - Google Patents

Abstract

The present invention relates to a coverage extension technology in a CDMA mobile telephone network, and in particular, a frequency conversion mobile telephone repeater having economical efficiency that can effectively eliminate a shadow area in a suburban area without the need for expensive base stations. It is about the operation method.

A feature of the present invention is to install the first or second repeater or more repeaters between the base station and the terminal to extend the coverage of the mobile communication base station, filtering only the designated FA among the FA in service in the first repeater after filtering It converts the link FA into transmission with the second repeater, and in the second repeater, the transmitted link FA is filtered down to the intermediate frequency and reduced to the original service designated FA to transmit communication with the terminal. The present invention relates to a frequency conversion mobile telephone repeater and its operation method that effectively solves the shadowed area in a mountainous area or a suburban area by arranging a repeater.

Description

Frequency conversion mobile telephone repeater and its operation method

The present invention relates to coverage expansion in a CDMA mobile telephone network, and more particularly, to a frequency conversion mobile telephone repeater and a method of operating the same, capable of effectively eliminating shadow areas in suburban areas without the need for expensive base stations. .

As is widely known, coverage expansion in a mobile telephone network is realized through expansion of base stations or repeaters.

A terminal subscriber in one base station service area can access another terminal subscriber in the service area of another base station, but cannot access if the other mobile terminal or its mobile terminal is out of the base station service area. do.

It is necessary to install as many mobile telephone base stations as possible to remove the service area limitation in the mobile telephone network. However, in mountainous areas or island areas where the utilization efficiency is lower than that of the base station expansion facilities, the economic problems of base station equipment costs are not considered. Can't.

This is because in urban areas, there is an excessive user waiting problem more than the number of subscribers allocated to each base station, and the coverage of the base stations in the mountainous areas has been narrowed by narrowing the coverage of the base stations. Despite the fact that it is installed sparsely under the conditions set as, the use frequency is only a small level compared to the city center, so it is economically burdened on the mobile phone operator side.

Therefore, mobile phone providers will install small base stations or repeaters to enable mobile phone calls in shaded areas, such as mountainous or suburban areas where there is little call volume.

Here, the repeater has a coverage antenna for transmitting and receiving RF signals with the terminal side and a donor antenna for transmitting and receiving RF signals with the base station, and the repeater amplifies only the signal strength as it is received from the terminal or base station side. Since only a simple amplifier function of retransmitting is performed, the installation and operation of the repeater is impossible due to the oscillation phenomenon caused by mutual interference without blocking the RF propagation between the donor antenna and the coverage antenna of the repeater.

Therefore, the repeater installation operation for coverage expansion of the base station is difficult to apply in an area where radio wave blocking is impossible, and is limitedly installed and operated only in an area where the donor antenna and the coverage antenna can be separated electromagnetically, such as above ground and underground roads.

The limitation problem for the installation area of the repeater for coverage expansion of the base station can be solved through the microwave link method.

However, repeater operation using microwaves cannot avoid the propagation loss due to the extra high frequency microwave wave, and it is very difficult in Korean terrain because of the restriction that there should be no obstacles between the links between repeaters. It has a disadvantage.

SUMMARY OF THE INVENTION An object of the present invention is to provide a frequency conversion mobile telephone repeater having economical efficiency in effectively eliminating shadowed areas in suburban or mountainous regions with only low-cost repeaters without the need for additional costly base stations when expanding the coverage of CDMA mobile telephone networks. And to provide a method of operation.

A feature of the present invention is to install the first and second repeaters between the base station and the terminal to extend the coverage of the mobile communication base station, filtering only the designated FA among the FAs in service in the first repeater to the intermediate frequency and then to link FA Converts and transmits the communication with the second repeater, and in the second repeater, the transmitted link FA is filtered down to the intermediate frequency and then reduced to the original service designation FA to transmit and communicate with the terminal. It is to effectively solve the shaded areas in the region or suburbs.

1 is a block diagram of an embodiment of a frequency conversion mobile telephone relay system according to the present invention.

2 is a diagram illustrating a repeating arrangement of relaying period coverage for covering an arbitrary shadow area in a frequency conversion mobile telephone relay system according to the present invention.

3 is a diagram illustrating a relay connection between a base station and a terminal using a single or an odd number of repeaters in a frequency conversion mobile telephone relay system according to the present invention.

4 is a circuit block diagram of a frequency conversion repeater according to the present invention.

Explanation of symbols for the main parts of the drawings

10: base station 12, 14, 18: repeater

16: terminal 20, 32: antenna

22, 30: duplexer 24, 34: LNA

26, 36: IF module 28, 38: LPA

Referring to the accompanying drawings, a system configuration and a method of operating the apparatus of the present invention will be described.

1 is an exemplary system block diagram for a frequency conversion mobile telephone repeater according to the present invention.

As referred to herein, the apparatus of the present invention includes the first and second repeaters 12 having a frequency conversion function between the terminal 16 located outside the service area A of the mobile telephone base station 10 and the base station 10. , 14) or more repeaters are evenly deployed to substantially expand the coverage area of the base station.

Between the antenna of the base station 10 and the first antenna (donor antenna) of the first repeater 12 in the service area A, the forward (forward: from the base station to the terminal) frequency signal fa and reverse (reverse: In the terminal, the frequency signal fb is designed to communicate with each other within a given first FA band.

Also, between the coverage antenna of the first repeater 12 and the donor antenna of the second repeater 14, forward and reverse frequency signals are designed to communicate with each other within the second FA band, and the second repeater 14 and the terminal are designed to communicate with each other. In (16), the forward and reverse frequency signals are designed to communicate with each other again in the first FA band.

Accordingly, the first and second repeaters 12 and 14 each include a frequency converting device for converting the frequency signal of the first FA band into the frequency signal of the second FA band.

For example, in the current digital mobile communication system (CDMA), channel assignment (FA) in a given frequency band by mobile carrier is shown in the 800 MHz band, the forward and reverse frequencies are 45 MHz, and 1.23 MHz at each forward and reverse frequency. It is composed of a plurality of channels having a width of.

Therefore, the narrow call of the mobile phone is basically made by the forward frequency signal and the reverse frequency signal having a frequency separation of 45 MHz in one frequency allocation (FA) area.

In general, the frequency of oral mobile subscribers in urban areas is high, and all frequency (channel) allocations (FA₁ ~ FAn) within the mobile communication frequency bands approved by each service provider are used efficiently, rather than the need for repeaters for coverage expansion. It is desirable to add another base station that can increase the number of simultaneous callers within a certain area.

However, in the suburban or mountainous areas, the frequency of use of the assigned channel of the base station is significantly lower than that of the city center, so that only a part of the assigned channel has little effect on the mobile phone service. It is possible to add a repeater to expand the coverage of the base station rather than the base station.

Therefore, as shown in FIG. 1, the base station 10 and the first repeater 12 located in the coverage A communicate with each other by the forward and reverse frequency signals fa and fb given by the first allocation channel FA1. The first repeater 12 in the coverage A area and the second repeater 14 in the coverage B area are forward and backward frequency signals fa and fb given by the second allocation channel FA2. ), And the forward and reverse frequencies given by the first allocated channel FA1 as in the coverage A region between the second repeater 14 and the terminal 16 in the coverage B region. The signals fa and fb communicate with each other.

In this case, the area C is a shaded area, and if the terminal is in this area, the call connection becomes impossible. Therefore, the generation of the shaded area for the area C of FIG. 1 can be eliminated by partially overlapping the coverage of the first and second repeaters 12 and 14 as shown in FIG. 2.

3 is a configuration diagram for relay connection between a base station and a terminal using a single or an odd number of repeaters in a frequency change mobile telephone relay system according to the present invention.

In this case, in addition to the frequency double conversion relay method between the base station 10 and the terminal 16 using the first and second repeaters 12 and 14, another relay method may include a base station and a terminal using a single frequency conversion repeater or an odd number of repeaters. The call connection model is shown.

Specifically, in the base station 10, the base station 10 may communicate with the third repeater 18 by using forward and reverse frequencies on a second assigned channel (FA not used). A wireless transmission and reception unit is installed to transmit and receive at a second FA channel allocation frequency therein, and a first frequency allocation frequency converted by the third repeater between the third repeater 18 and the terminal 16 is provided. It is installed to communicate with forward and reverse frequency signal of).

At this time, the third repeater having coverage of the D area is installed in the coverage A area of the base station. Accordingly, the base station 10 can exchange the same communication signal information with the terminal through the first and second repeaters 12 and 14 of different allocation channels.

4 is an internal circuit block diagram of a frequency conversion repeater according to the present invention.

As referred to herein, the first duplexer 22 filters the forward frequency band signal of a particular FA channel (first FA channel) received via the first antenna 20 and is 45 MHz away from the reverse frequency band signal. After separating from and configured to be input to the first IF module 26 through the first LNA (24).

In addition, the first IF module 26 is configured to be applied to the second duplexer 30 through the first LPA (28) after the SAW filtering down to the intermediate frequency and converted to the second FA channel frequency band. The forward signal component for the relay filtered by the second duplexer 30 is configured to be transmitted to the terminal or the second frequency conversion repeater through the second antenna 32.

The reverse frequency band signal of the FA channel (second FA channel) received through the second antenna 32 is separated from the forward frequency band signal at 45 MHz from the second duplexer 30 and then the second LNA 34. The second IF module 36 is configured to be input to the second IF module 36, and the second IF module 36 filters the frequency band of the second FA channel down to the intermediate frequency IF and then inverses the first FA. After conversion, it is configured to be applied to the first duplexer 22 via the second LPA 38, and the relay reverse signal component filtered by the first duplexer 22 is applied to the first through the first antenna 20. Configure the frequency conversion repeater or base station to be transmitted.

The first and second duplexers and the IF module include a filter having a very precise frequency characteristic because it has to convert the transmit / receive frequency into an adjacent FA within a frequency band applied to the mobile phone operator.

In particular, the flatness and skirt characteristics of the duplexer should be designed to maintain optimal conditions depending on the number of FAs used.

The first and second LPAs adopt a higher efficiency LPA than the HPA as a terminating power amplifier of the repeater, and the first and second LNAs of the low noise amplifier are operated so that the saturation caused by the path loss between the repeaters does not degrade the waveform quality. The property must be designed with consideration in mind.

Referring to the operation of the frequency conversion repeater is configured as follows.

First of all, the basic configuration of the frequency conversion repeater for mobile phone repeater is to change the transmission and reception FAs within the mobile phone frequency band. When down-converting and up-converting the input / output signal frequencies in the forward and reverse IF modules, Alternatively, the desired input and output FAs can be obtained, and the input or output signal of the channel band FA required by the filters installed at the front and rear ends of these IF modules passes.

For example, when the base station and the terminal are connected to each other by using a repeater, the connection RF band of the base station 10 and the repeater 18 is determined as the second FA, and the connection RF band of the repeater 18 and the terminal 16 is If it is determined as the first FA, the forward input signal of the second FA received from the antenna of the base station 10 to the first antenna (donor antenna) 20 of the repeater is filtered while passing through the first duplexer 22 to obtain a low noise amplifier. After being amplified in the first LNA 24 is applied to the first IF module 26.

The input signal of the second FA channel is mixed with the second FA reference frequency signal pre-programmed in the first IF module 26 to be frequency-converted into the channel of the first FA, and then the first LPA (which is a high-efficiency termination amplifier). Input to the second duplexer 30 via 28).

The second duplexer 30 filters the input signal frequency-converted by the forward frequency filter value of the second FA channel and transmits the input signal to the terminal through the second antenna (coverage antenna) 32.

On the contrary, the reverse signal on the second FA channel transmitted from the terminal side to the coverage antenna 32 side of the repeater is reverse signal filtering frequency band of the second FA channel 45 MHz away from the forward signal filtering frequency band at the second duplexer 30. After passing through and then amplified in the second LNA 34, which is a low noise amplifier, it is applied to the second IF module 36.

The reverse input signal of the second FA channel is converted into a channel of the first FA whose frequency is mixed with the first FA reference frequency signal pre-programmed in the second IF module 36, and then the second LPA is a high efficiency termination amplifier. After being amplified at 38, the signal is transmitted to the base station through the first duplexer 22 and the first antenna 20.

In this way, the base station and the terminal are connected through a repeater installed in the middle.

The above describes the connection process between the terminal and the base station through a single frequency conversion repeater, but this does not limit the technical spirit of the present invention. Therefore, it will be apparent that various modifications within the technical scope of the present invention described above are possible.

As described above, the present invention provides a repeater to extend coverage by installing a repeater in order to enable a mobile phone call in a shaded area such as a mountainous area or a suburban area where a small amount of communication is performed. In order to solve the problem of radio interference at the same frequency, the coverage of the mobile communication network can be economically expanded by utilizing the unused FA (channel) within the frequency band authorized by the mobile phone operator as the link channel in the relay period. You can get a unique effect.

Claims (4)

In a coverage extension system of a mobile telephone using a repeater, a set of first and second repeaters or more repeaters having an even number of overlapping coverages between a base station and an arbitrary area where a terminal is located for coverage expansion of the base station Each repeater is provided with a frequency converter for converting the selected FA channel and the FA channel which is not used in the mobile phone license band to be different from the donor side and the coverage side FA channel of the repeater. A frequency conversion mobile telephone repeater, characterized in that. The method of claim 1, wherein the repeater is a constant separation frequency (45MHz) between the forward signal on the first FA channel input through the first antenna 20 and the reverse signal on the first FA channel output through the first antenna The first duplexer 22 and the forward signal on the second FA channel input through the second antenna 32 and the reverse signal on the second FA channel output through the second antenna at a predetermined separation frequency ( 45 MHz), a second duplexer 22 for filtering each, a first IF module 26 for converting a forward signal of a first FA channel of the first duplexer 22 to a second FA channel, and the second And a second IF module (36) for converting the reverse signal of the second FA channel of the duplexer (30) into the first FA channel. A method for extending coverage of a mobile telephone using a repeater, comprising: a first FA channel being serviced among a plurality of FA channels for accessing a relay station with a base station in a mobile telephone service band allocated by a mobile telephone operator; A method of operating a frequency converted mobile telephone repeater, wherein the frequency conversion of the mobile telephone is extended after the frequency conversion from the repeater to the FA channel is performed by linking with another repeater to the second FA channel. 4. The method of claim 3, wherein coverage is extended to one or more odd-numbered repeaters by directly transmitting and receiving a link FA at the base station.