KR100541862B1 - Repeating apparatus using virtual primary frequency channel and method thereof - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

A repeater of a mobile communication system.

2. The technical problem to be solved by the invention

With repeaters, it is possible to increase the number of subscribers and expand the service area without sacrificing call quality at low cost.

3. Summary of Solution to Invention

Summary of the Invention The present invention provides a repeater for a code division multiple access type mobile communication system, comprising: a forward transmitter / receiver for filtering and amplifying and outputting only a frequency channel assigned to a repeater among signals received from a base station; and a frequency channel assigned to the repeater. And a primary frequency channel generator for generating and outputting a virtual primary frequency channel including information, and a reverse transceiver for amplifying a reverse channel among the received radio signals and transmitting the amplified reverse channel to the base station. do.

4. Important uses of the invention

It is used to expand the service area in mobile communication system, solve the shadow area, and improve the call quality under the given service area.

Repeater, base station, mobile communication system, shaded area.

Description

Repeater apparatus and virtual primary frequency channel and method

1 is a diagram illustrating a call right model in a conventional mobile communication system having a cell structure.

2 is a diagram illustrating a forward / reverse link input / output waveform of a conventional mobile communication system repeater.

3 is a diagram illustrating a call right model in a mobile communication system according to the present invention.

4 is a diagram illustrating a forward reverse link input / output waveform in a service area of a mobile communication system repeater according to the present invention.

5 is a diagram illustrating a forward reverse link input / output waveform in a service area of a mobile communication system repeater according to another embodiment of the present invention.

6 is a block diagram of a mobile communication system repeater according to the present invention.

Explanation of symbols on the main parts of the drawings

610: forward and reception unit 611, 631: low noise amplifier

612, 632: filter 613, 632: amplifier

614: synthesizer 620: virtual primary frequency channel generator

621: GPS 622: time / frequency generator

623: modulation / baseband processing unit 624: RF unit

630: reverse transceiver 640, 650: duplexer

661 to 669: input and output waveforms

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a repeater for extending a service area using a basic algorithm of a code division multiple access method in a mobile communication system of a code division multiple access (CDMA) method. The present invention relates to a repeater and a method capable of improving call quality while being low in cost.

1 is a diagram illustrating a call right model in a conventional mobile communication system having a cell structure.

In the conventional mobile communication system, in order to maximize the utilization of the limited frequency resource, the cell is divided into service areas in the form of cell structure, and a predetermined area is spaced apart (mostly, the main interference is generated from 18 base stations of the first and second base stations). It is designed in such a way that the frequency can be reused.

In the cell-structured mobile communication wireless network, frequency allocation of analog systems reuses frequencies at a fixed distance, whereas in mobile communication systems employing code division multiple access, PN (Pseudo random noise) is turned off at the same frequency band instead of frequency. The concept of reusing sets is to accommodate more subscribers than analog.

Since the code division multiple access system divides each subscriber into different code channels in the same frequency band, all signals other than the self code channel signal act as interference.

However, if the signal strength other than its own communication channel exceeds a certain threshold, there is a problem that the call quality is degraded and the call is impossible. Under a certain cell radius, the number of other talk channels other than its talk channel has an absolute effect on the strength of the interfering signal. In mobile communication networks (commercially fixed wireless networks, which are already commercially available), an increase in the amount of interference due to an increase in subscribers or an increase in the amount of interference coming from other cells is a major cause of deterioration in call quality and subscriber capacity.

When a considerable time has elapsed since the initial service point, a change in the cell is also inevitable because the radio wave environment changes according to the change in the number of subscribers and the construction of the building. Changes in the cell due to changes in the radio environment (additional construction of base stations, capacity expansion, etc.) incur significant costs.

Therefore, in a system where call is limited by interference, such as code division multiple access, balanced wireless network design considering the difference of transmission loss in building interior, exterior and underground space is needed to minimize the cost of cell change. It is important.

Basically, the radius of a cell should be set within the capacity range of resources that a cell can accommodate. However, if a cell is designed to secure coverage in a building in a downtown area, overlapping areas are distributed to a large part from the outside, which is the main cause of increasing the amount of interference. Therefore, the initial wireless network design is designed to have a minimum amount of interference from the outside, and is designed as a separate method such as a repeater and a micro cell in the building and underground space.

Although the use of repeaters is widely used as a method of eliminating shadow areas at low cost, wireless network design using repeaters is economical because there is a disadvantage of generating another interference in a limited amount of interference such as code division multiple access. It should be scrutinized and applied. In addition, when designing and optimizing the wireless network, the design of the wireless network according to the change of the radio wave environment should be more accurately predicted, and the design should be designed to actively optimize the wireless network at the minimum cost and the change in the radio environment. do.

2 is a diagram illustrating a forward / reverse link input / output waveform of a conventional mobile communication system repeater.

In general, as shown in FIG. 2, all conventional repeaters use a method of simply amplifying an RF signal in a shadow area such as a building or an underground space to be serviced. Conventionally, an optical dispersion optical repeater which extends and amplifies the communication distance of an RF signal by connecting a mortgage station with a main cable and a relay section, and a frequency converter for converting and transmitting a frequency section of an RF signal. Repeaters, RF repeaters that simply amplify the RF signal is used. These repeaters are the repeaters of the concept of simply amplifying the RF signal to secure the service area. The use of such relays has a problem in that the call quality is degraded due to the PN pollution phenomenon transmitted from the repeater as well as the mortgage station. In particular, in highlands and high-rise buildings, the concentration of PN offsets from neighboring base stations as well as mortgage stations is severe, resulting in a significant drop in call quality due to handoffs, even though the call is disconnected or there is no location movement. There is a problem.

In other words, if the existing repeater is used, there is a problem that the capacity of the system decreases due to the increase in the amount of interference caused by the increase of subscribers and the concentration of the PN offset from the base station and the repeater.

Although the interference due to the signal inflow from the outside other than the repeater does not occur, the method of simply amplifying the signal that is already interfered can solve the shadow area, but there is a problem that can not improve the call quality.

In addition to the increase of subscribers in the shadow area through the repeater, there is another method that can be used to increase the FA of the base station, but the method of increasing the FA also has a certain limit. In order to increase one FA in the base station, hundreds of millions of dollars are usually invested, and the signal output from the expanded FA is treated as noise to other subscribers, which causes a problem of deterioration of call quality.

In addition, the output of the base station should be increased by the increased FA, but the cost for this is increased exponentially, there is a big cost burden.

SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a repeater and a method capable of economically increasing the number of mobile stations available, as well as preventing deterioration of call quality in increasing subscribers and expanding service areas using repeaters. Is in.

In the repeater of the code division multiple access method mobile communication system for achieving the above object, a band-blocking of the primary frequency channel of the signal received from the base station, and amplifying and outputting the forward frequency channel assigned to the repeater A virtual primary frequency channel generator for generating a virtual primary frequency channel including information about a forward frequency channel allocated to the repeater, a repeater, and amplifying a reverse channel among the received radio signals to the base station And a reverse transmitting / receiving unit for transmitting.

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

3 is a diagram showing a call right model in a mobile communication system according to the present invention, FIG. 4 is a diagram showing a forward reverse link input / output waveform in a service area of a mobile communication system repeater according to the present invention, and FIG. FIG. 6 is a diagram illustrating a forward reverse link input / output waveform in a mobile communication system repeater service area according to another embodiment of the present invention. FIG. 6 is a block diagram of a mobile communication system repeater according to the present invention.

In the wireless mobile phone service, the mutual recognition between the base station and the mobile station is performed by the control channel operation and recognition procedure according to each protocol (AMPS, GSM, CDMA, etc.). The present invention relates to a repeater and a method in which a repeater indirectly controls a mobile station by utilizing a primary frequency channel among functions performed by a base station of a code division multiple access method.

In general, in a mobile communication system using a code division multiple access method, when a terminal is initially connected to a base station and synchronized, it searches for and synchronizes a primary frequency channel, which is the first FA, and lists the channels included in the primary frequency channel. It changes the channel for the call accordingly. Each frequency channel FA including a primary frequency channel includes a pilot channel, a synchronization channel, and a call channel (Pilot, Sync, Paging channel), and a channel list for each frequency channel FA is a call channel. It is included in the system parameter message. Typically, a band allocated to one operator may use frequency channels having several different frequency bands, and each frequency channel includes a pilot channel, a synchronization channel, a call channel, and a plurality of talk channels, each separated by a PN code. It will contain the code channel.

The present invention is a repeater that allows users located in the sound region through the virtual primary frequency channel and a unique channel assigned to the repeater to enable the call, as shown in FIG. A primary frequency channel generator 620 and a reverse transmitter / receiver 630 are provided, which will be described in detail below.

The forward transmission / reception unit 610 amplifies and outputs the forward frequency channel 663 allocated to the repeater among the signals 661 received from the base station. The forward transmission / reception unit 610 band-passes the forward frequency channel assigned to the repeater among the low noise amplifier 611 for low noise amplifying the signal 661 received from the base station, and the low noise amplified signal 662. And a filter 612 for band filtering 663 by blocking the primary frequency channel, and an amplifier 613 for amplifying 664 the filtered signal 663.

The virtual primary frequency channel generator 620 generates a virtual primary frequency channel 666 including information about a channel assigned to the repeater. The virtual primary frequency channel generator 620 includes a GPS receiver 621 and a time / frequency generator 622 for generating the same reference time and reference frequency as the base station by the GPS receiver 621. Doing. In addition, the virtual primary frequency channel generator 620 generates a virtual primary frequency channel including the forward frequency channel information assigned to the repeater based on the value output from the time / frequency generator 622, A modulation / baseband processor 623 for converting and outputting to the baseband, and an RF unit 624 for converting and outputting the output signal of the modulation / baseband processor 623 to a radio frequency.

That is, the virtual primary frequency channel generator 620 inserts only the channel (channel allocated exclusively to the repeater) list information that is band-passed and filtered by the forward transmitter / receiver 610 into the paging channel. Generate a primary frequency channel. In other words, the repeater does not provide channel list information actually used by the base station to the terminal and transmits only the information about the channel uniquely assigned to the repeater by inserting it into the virtual primary frequency channel. The primary frequency channel transmitted from the base station includes channel list information about each channel transmitted by the base station, but the call channel of the frequency channel assigned to the repeater includes only the channel list information assigned to the repeater and is transmitted from the repeater. The virtual primary frequency channel to be included contains only channel list information allocated to the repeater.

The reverse transmitting / receiving unit 630 amplifies the reverse channel 667 among the wireless signals in the shaded area and transmits the reverse channel 667 to the base station. The backward transmission / reception unit 630 filters the low noise amplifier 631 for low noise amplifying the received wireless signal, a filter 632 for band-passing the assigned reverse channel among the low noise amplified signals, and a filter 632. An amplifier 633 is provided to amplify 669 the obtained signal 668.

The signals 664 and 666 output from the forward transmitting / receiving unit 610 and the virtual primary frequency channel generator 620 are summed 665 at the adder 614 to the sound region through the duplexer 640 and the antenna. It is sent out. That is, only the virtual primary frequency channel and the channel assigned to the repeater are transmitted.

The signal output from the reverse transceiver 630 is transmitted to the base station through the duplexer 650 and the antenna. At this time, the antenna used for transmission with the base station is a directional antenna such as Yagi antenna for minimizing interference in the mobile station outside and using redundant repeaters in other regions. On the other hand, for communication with the base station can be used as an optical cable or a wired cable as conventional.

Hereinafter, the operation of the repeater according to the present invention will be described with reference to FIGS. 3 to 5.

As shown in FIG. 3, a base station to be used as a dedicated frequency channel for a repeater is operated in one cluster. Base station selection of base stations A1 and B1 to operate the dedicated frequency channel of the repeater includes a base station having a sufficient distance (a sufficient distance to suppress the mutual interference as much as possible) and a base station having a low frequency of communication with the base station that will operate another repeater dedicated frequency channel. (Traffic dispersion effect) is selected to be advantageous for minimizing the amount of call distribution and interference. If the place where the repeater is installed is an enclosed space such as an underground space, and the amount of radiation exposed to the outside is extremely small, the repeater can be operated by using the channel of the same band in other adjacent base stations. Of course, you can use a repeater.

4 is an input / output waveform of the forward and reverse links in the inherent service area of the base stations A1 and B1 of FIG. 3, which operates a repeater dedicated frequency channel, and the operation method is A2, A3, A4, A5, A6, A7, B2 of FIG. , B3, B4, B5, B6, B7 It operates the same as the base station, but operates a separately assigned channel (RepFA). Also, the channel list message ( _Rep FA channel list) dedicated to the repeater is transmitted to the channel list message among the messages of the paging channel included in each channel ( _1st FA to _(n-1) FA) used by the base station. I never do that.

On the other hand, in the dedicated channel ( _Rep FA) dedicated to the repeater, only its own channel list information is transmitted. In the service area (outside) of the base station, not the repeater service area, all the used frequency channels ( _1st FA to _(n-1) FA) including the repeater dedicated frequency channel exist, but the channels actually used ( _1st FA to _{(n-) 1) In} FA), there is no channel list information allocated exclusively for the repeater, so the mobile stations are tuned to only one frequency of each corresponding frequency channel ( _1st FA to _(n-1) FA) by the algorithm adopted by the system. However, tuning to the dedicated frequency channel ( _Rep FA) assigned to the repeater is not possible.

Therefore, the mobile stations in the service area unique to the base station in the system operating the repeater-dedicated frequency are partially distributed in the _1st FA to _(n-1) FA of the base stations A1, A2, A3, A4, A5, A6, and A7 of _FIG. The mobiles are concentrated on the _Rep FA, which is a dedicated frequency channel for A1's repeater. Therefore, the amount of interference of the mobile station concentrated in the _Rep FA is subtracted from the _1st FA to _(n-1) FAs of the A1, A2, A3, A4, A5, A6, and A7 base stations to reduce the amount of interference.

5 is a _2nd not required in the relay interval shown in FIG. 4 as the forward and reverse link input and output waveforms of the repeater coverage area that is sent when using a dedicated frequency channel _(Rep FA) assigned to the repeater using a repeater forward link configuration time, filter Frequency components from FA to _(n-1) FA) are removed and sent through the filter 612. In the repeater reverse link configuration, a filter 632 is used to remove unnecessary frequency components from _1st FA to (n-1) FA in the relay section shown in FIG. 4 to be transmitted to the base station. In the embodiment according to FIG. 2, since the amplification and relaying is performed for all bands from _1st FA to nFA, not only the amount of unnecessary interference between the base station and the relay period increases, but also due to excessive overlap between the base station and the other station, that is, frequent handoff. The allocation rate causes loss of communication channel resources and increased interference. However, the invention according to FIG. 5 can maximize the utilization of resources by minimizing the amount of mutual interference by minimizing and centralizing unnecessary signals.

That is, if the number of used frequency channels of the A1, A2, A3, A4, A5, A6, and A7 base stations is n, it is possible to ensure a smooth service area with only (n-1) or fewer channels.

In the case of the embodiment of FIG. 5, the forward transmission / reception unit 610 band- _passs only the dedicated channel _Rep FA assigned to the repeater, and the virtual primary frequency channel generator 620 allocates the dedicated channel dedicated to the repeater ( A virtual primary frequency channel ( _1st FA) including channel list information regarding _Rep FA) is generated and wirelessly transmitted together with the assigned channel ( _Rep FA) (see FIG. 5). The reverse transmitting / receiving unit 630 also band-passes only the reverse channel ( _Rep FA) dedicated to the repeater and transmits it to the base station.

As described above, the present invention operates a repeater using a virtual primary frequency channel and a channel dedicated to the repeater, thereby minimizing the concentration of base station reception interference, mobile station reception interference, and centralization of PN offset in highlands and skyscrapers. It can fundamentally solve the problem of poor call quality, can maximize the capacity within the system resources, can maximize the utilization of resources, there is an advantage that can reduce the base station system cost. In addition, although the conventional repeater is inevitable to relocate the repeater or change the specification when the base station is relocated due to changes in the radio environment and subscriber changes, the present invention can be operated irrespective of the change in the radio environment, thus minimizing the repeater operation maintenance cost have.

Claims (9)

In the repeater of the code division multiple access method mobile communication system, A forward transmitting / receiving unit which band-blocks other frequency channels among signals received from the base station, and amplifies and outputs the forward frequency channel assigned to the repeater; A virtual primary frequency channel generator for generating a virtual primary frequency channel including information on a forward frequency channel assigned to the repeater; And, A reverse transmitting and receiving unit for amplifying a reverse frequency channel among the received radio signals and transmitting the same to the base station; Repeater using a virtual primary frequency channel characterized in that it comprises a. The method according to claim 1, The forward transmission and reception unit, A low noise amplifier for low noise amplifying a signal received from the base station; A filter for band-pass filtering only the assigned forward frequency channel among the low noise amplified signals; And, An amplifier for amplifying the filtered signal: Repeater using a virtual primary frequency channel characterized in that it comprises a. The method according to claim 1, The reverse transmitting and receiving unit, A low noise amplifier for low noise amplifying the received wireless signal; A filter for bandpass filtering only an assigned reverse channel of the low noise amplified signal; An amplifier for amplifying the filtered signal: Repeater using a virtual primary frequency channel characterized in that it comprises a. The method according to claim 1, The repeater, And a directional antenna for wirelessly communicating with the base station. The method according to any one of claims 1 to 4, The virtual primary frequency channel generator, GPS receiver; A time / frequency generator for generating a reference time and a reference frequency by the GPS receiver; A modulation / baseband processor for generating a virtual primary frequency channel including the allocated forward frequency channel information based on a value output from the time / frequency generator and converting the baseband to a baseband; And, RF unit for converting the output signal of the modulation / baseband processing unit into a radio frequency Repeater using a virtual primary frequency channel characterized in that it comprises a. In the relay method of the code division multiple access method mobile communication system, A first step of the base station transmitting channel list information directly operated by the base station through the primary frequency channel; A second step of repeating, by the repeater dependent on the base station, the primary frequency channel among the signals received from the base station, and band-passing only the forward channel assigned to the repeater; A third step of generating, by the repeater, a virtual primary frequency channel including only channel list information allocated to the repeater; A fourth step of wirelessly transmitting the output signal of the second step and the virtual primary frequency channel of the third step; A fifth step of amplifying a reverse channel among wireless signals received by the repeater and transmitting the amplified reverse channel to the base station; Relay method using a virtual primary frequency channel characterized in that it comprises a. The method according to claim 6, The virtual primary frequency channel, And a call channel including the allocated forward channel list information, a pilot channel, and a synchronization channel. The method according to claim 6, In the fifth step, And filtering only a reverse channel allocated to the repeater using a band pass filter among the received radio signals, and amplifying the filtered signal and transmitting the filtered signal to the base station. The method according to claim 6 or 8, The transmission to the base station in step 5, A relay method using a virtual primary frequency channel, characterized in that the optical cable or by a wired or directional antenna.

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