CN102932029A - Long term evolution (LTE) indoor distribution system and double-path frequency conversion equipment and method thereof - Google Patents

Abstract

The invention provides an LTE indoor distribution system and its dual-channel frequency conversion equipment and method. The device includes a first part and a second part; the first part includes: a first branch and a second branch; the second part includes: a third branch and a fourth branch; the first branch and The second branch is respectively used to transmit a signal sent to the other end; the third branch and the fourth branch are respectively used to transmit a signal received from the other end; the first branch The composition structure of the road is the same as that of the second branch; the composition structure of the third branch is the same as that of the fourth branch. The invention provides a specific solution for the LTE indoor distribution system supporting MIMO.

Description

LTE indoor distribution system and its dual-channel frequency conversion equipment and method

technical field

The present invention relates to mobile communication technology, in particular to a long term evolution (Long Term Evolution, LTE) indoor distribution system and its dual-channel frequency conversion equipment and method.

Background technique

With the development of the Internet, users' demand for data services is increasing day by day, and surveys show that more data services occur in indoor scenarios. Multiple Input Multiple Output (MIMO) technology is one of the important means for Long Term Evolution (LTE) to increase system capacity, but most of the indoor distribution systems for 2G/3G applications are traditional methods that do not support MIMO. Single-user throughput and cell throughput are low, which cannot meet the requirements of LTE system capacity. After the introduction of LTE, it is an inevitable trend of network construction to transform the indoor distribution system on the basis of the existing distribution system to meet the MIMO application requirements of LTE.

Figure 1 is a schematic diagram of a scheme for transmitting multiple signals through a single feeder using frequency conversion combining technology. This scheme provides a convenient choice for the future application of MIMO in indoor wireless networks. The baseband processing unit (Base Band Unit, BBU) sends out the baseband signal, which is transmitted to the dual-transmission remote radio frequency signal processing unit (Remote Radio Unit, RRU) through the optical fiber. The two low-power radio frequency signals sent by the RRU pass through the near-end module respectively. Down-conversion, into intermediate frequency signals of different frequencies and combined output, and then combined with the existing radio frequency system signal, the combined MIMO intermediate frequency signal and other system radio frequency signals are transmitted on a main feeder, and then passed through The power divider is divided into multiple channels to meet the requirements of space division multiplexing; when the multi-system signal is transmitted to the remote module, the two-way LTE IF signal is separated from the RF signal of other systems through the splitter, and then passed through the upper The frequency is converted to the same radio frequency as the RRU output, and transmitted to the two polarization input ports of the dual-polarization indoor distribution antenna to achieve the purpose of indoor distribution MIMO.

However, at present, only the schematic diagram shown in FIG. 1 is given, and there is no specific implementation scheme, especially no specific scheme on how to realize frequency conversion.

Contents of the invention

In view of this, an embodiment of the present invention provides an LTE indoor distribution system and its dual-channel frequency conversion equipment and method to solve the technical problem that there is no specific frequency conversion scheme in the LTE indoor distribution system in the prior art.

On the one hand, a dual-channel frequency conversion device for an LTE indoor distribution system is provided, including:

Part I and Part II;

The first part includes: a first branch and a second branch;

The second part includes: a third branch and a fourth branch;

The first branch and the second branch are respectively used to transmit a signal sent to the other end;

The third branch and the fourth branch are respectively used to transmit a signal received from the other end;

The composition and structure of the first branch and the second branch are the same;

The composition and structure of the third branch and the fourth branch are the same.

In another aspect, an LTE indoor distribution system is provided, including the above-mentioned dual-channel frequency conversion equipment.

In another aspect, a dual-channel frequency conversion method for an LTE indoor distribution system is provided, including:

The first branch and the second branch are respectively used to transmit a signal sent to the other end;

using the third branch and the fourth branch to respectively transmit a signal received from the other end;

The composition and structure of the first branch and the second branch are the same;

The composition and structure of the third branch and the fourth branch are the same.

Through the above technical solution, a two-way frequency conversion scheme is given. In this two-way frequency conversion scheme, whether it is the two-way signals to be sent to the other end or the two-way signals received from the other end, the two-way signals pass through The path adopts the same composition structure, which can realize symmetrical frequency conversion, not only can realize frequency conversion processing, but also can reduce signal delay.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings that need to be used in the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of an LTE indoor distribution system in the prior art;

Fig. 2 is the structural representation of an embodiment of near-end machine in the present invention;

Fig. 3 is a structural schematic diagram of an embodiment of the remote machine in the present invention;

Fig. 4 is a schematic structural view of another embodiment of the near-end machine in the present invention;

Fig. 5 is a structural schematic diagram of another embodiment of the remote machine in the present invention;

FIG. 6 is a schematic diagram of downlink signal transmission in the present invention;

FIG. 7 is a schematic diagram of uplink signal transmission in the present invention;

Fig. 8 is a schematic flowchart of an embodiment of the dual-channel frequency conversion method of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The present invention provides an embodiment of a device, the device includes a first part and a second part; the first part includes: a first branch and a second branch; the second part includes: a third branch and a second branch Four branches; the first branch and the second branch are respectively used to transmit a signal sent to the other end; the third branch and the fourth branch are respectively used to transmit a signal from the For signals received at the other end: the first branch and the second branch have the same composition structure; the third branch and the fourth branch have the same composition structure.

The device may be a near-end device, and at this time, the device may be applied in the near-end module in FIG. 1 ; or, the device may also be a remote device, and in this case, the device may be applied in the remote module in FIG. 1 .

When the above-mentioned equipment is a near-end machine, the above-mentioned other end refers to a remote machine; or, when the above-mentioned equipment is a remote machine, the above-mentioned other end refers to a near-end machine.

For the near-end unit and the far-end unit, the paths of the uplink signal and the downlink signal are opposite. For example, when downlinking, the near-end unit sends a downlink signal to the far-end unit through the first part, and the downlink signal reaches the After the terminal machine, it is transmitted through the second part of the remote machine. When going up, the far-end unit sends an uplink signal to the near-end unit through the first part, and the uplink signal reaches the near-end unit for transmission through the second part of the near-end unit.

That is to say, when the device is a near-end device, the above-mentioned first branch and second branch are respectively two downlink signal processing branches, and the third branch and fourth branch are two uplink signal processing branches. road; or,

When the device is a remote machine, the above-mentioned first branch and second branch are respectively two uplink signal processing branches, and the third branch and fourth branch are two downlink signal processing branches.

In this embodiment, the first branch and the second branch use the same composition structure, and the third branch and the fourth branch use the same composition structure, so that the two signals sent or received can pass through the same path For transmission, that is, through symmetrical frequency conversion and channel combining technology, since the two channels of signals adopt symmetrical technology, the time delay of the two channels of LTE system signals can be reduced.

Preferably, the above-mentioned third branch and fourth branch respectively adopt a three-stage frequency conversion method.

Optionally, in the three-stage frequency conversion mode, the third branch and the fourth branch may respectively include:

A first filter, a first mixer, an intermediate frequency filter, an intermediate frequency amplifier, a second mixer, a second filter, a third mixer, a third filter and a power amplifier connected in series in sequence;

The first filter is used to perform first filtering processing on the signal received from the other end;

The first mixer is used to perform first frequency conversion processing on the first filtered signal;

The intermediate frequency filter is used to perform intermediate frequency filtering processing on the signal after the first frequency conversion processing;

The intermediate frequency amplifier is used to perform intermediate frequency amplification processing on the signal processed by the intermediate frequency filter;

The second mixer is used to perform second frequency conversion processing on the signal after the intermediate frequency amplified processing;

The second filter is used to perform second filtering processing on the signal after the second frequency conversion processing;

The third mixer is used to perform third frequency conversion processing on the second filtered signal;

The third filter is used to perform third filtering processing on the signal after the third frequency conversion processing;

The power amplifier is used to perform power amplification processing on the third filtered signal;

The signals after the power amplification processing are respectively sent to a receiving port of the RRU.

Further, when the device is a remote machine, the third branch and the fourth branch further include:

Automatic level control (Automatic Level Control, ALC), connected to the power amplifier, is used to perform automatic level control processing on the signal after the power amplification processing and send it to a receiving port of the RRU.

Optionally, the first branch and the second branch respectively adopt a one-stage frequency conversion method.

At this time, the first branch and the second branch respectively include:

A fourth mixer and a fourth filter connected in series in sequence;

The fourth mixer is used to perform fourth frequency conversion processing on the signal sent to the other end;

The fourth filter is used to perform fourth filtering processing on the signal after the fourth frequency conversion processing;

The signals after the fourth filtering process are combined and then sent to the other end.

Further, when the device is a remote machine, the first branch and the second branch further include:

A low-noise amplifier, connected in series with the fourth mixer, is used to perform low-noise amplification on the signal sent to the other end and send it to the fourth mixer.

In combination with the above description, the structures of the near-end unit and the far-end unit provided by the present invention can be referred to FIG. 2 and FIG. 3 .

Taking the near-end unit as an example, the first part adopts a one-stage frequency conversion method, and the two channels of the first branch and the second branch use different local oscillators so that the frequency shifting frequency does not overlap, and then they are combined to the output port.

The second part needs to use intermediate frequency filtering to distinguish the two signals from the same port at the far end, so a three-stage frequency conversion scheme is adopted: the first two stages of frequency conversion share the local oscillator to reduce the impact of local oscillator frequency drift; The third-stage frequency mixing shares the local oscillator with the corresponding downlink channel respectively.

The solution of the far-end unit is similar to that of the near-end unit, except that the processing of the uplink and downlink is just reversed; at the same time, a low-noise amplifier is added to the uplink signal processing process to meet the signal quality requirements.

The functions of each unit in Fig. 2 or Fig. 3 are as follows:

(1) Circulator: The control signal is transmitted in one direction, which plays the role of isolation and inhibits the reverse transmission of the signal. It can also be called an isolator;

(2) Mixer: realize the sum and difference processing of the processed signal frequency and the local oscillator signal frequency;

(3) Filter (including intermediate frequency filter): realize the passage of the required frequency signal and filter out the signal of unnecessary frequency;

(4) Combiner: realize the combination of two or more signals of different frequencies into one signal;

(5) Amplifiers (intermediate frequency amplifiers and low noise amplifiers in Figures 2 and 3), which can be radio frequency amplifiers or power amplifiers: to increase the output level or power of radio frequency signals;

(6) Two-power splitter: divide one signal into two signals according to the frequency, which is actually the reverse use of the combiner;

(7) Automatic Level Control (ALC): to stabilize the RF output signal power at a relatively constant amplitude value;

(8) Ports 1 and 2: the input/output ports of the near-end machine, which receive the two downlink LTE signals transmitted by the RRU, or input the two uplink LTE signals to the RRU;

(9) Ports 3 and 4: the input/output ports of the remote machine, that is, receive two uplink LTE signals transmitted from the antenna port, or input two downlink LTE signals to the antenna port;

(10) Ports a and b: the intermediate connection ports of the near-end unit and the far-end unit, and the two ports are connected through passive components and cables of the indoor distribution system.

The schematic diagram of the specific circuit implementation of the above-mentioned near-end machine and remote machine can be referred to in Figure 4 or Figure 5, and Figure 4 and Figure 5 are the schematic diagrams of the near-end machine and the remote machine respectively, wherein 2620-2650MHz is used as the downlink frequency 1. The uplink frequency is 2500-2530MHz, the downlink intermediate frequency is 1420-1490MHz, and the uplink intermediate frequency is 1300-1370MHz.

In this embodiment, due to the use of symmetrical frequency conversion and circuit combining technology, the low delay of the two signals can be realized; the uplink part of the near-end machine and the downlink part of the remote machine adopt a three-stage frequency conversion method, which can effectively suppress high-order harmonics and various Spurious clutter interference to achieve higher output frequency stability and spurious suppression performance; by adopting automatic level control at the end of the remote machine, it meets the requirements of MIMO technology for dual-channel signal output power balance.

With reference to the schematic structural diagram in FIG. 2 or FIG. 3 , reference may be made to FIG. 6 or FIG. 7 for a schematic diagram of a transmission process of a downlink signal and an uplink signal.

Figure 6 is a schematic diagram of downlink signal transmission in an embodiment of the present invention, wherein the BBU generates a baseband signal and sends it to the RRU; the RRU converts the received baseband signal into two LTE system radio frequency signals, and sends them to port 1 of the near-end device respectively and port 2; the near-end machine performs down-conversion processing on the received radio frequency signal, and the specific down-conversion processing scheme can refer to the first-level mixing part in Figure 2, which is the first part; after the down-conversion, the radio frequency signal is converted into an intermediate frequency signal, The combiner performs combination processing on the two-way IF signals to obtain the LTE IF signal, which is output from port a of the near-end machine; then it performs combination processing with other system signals, and the combined signal is a multi-system signal that can be combined in one Transmission in the cable; the power divider divides the signal into multiple channels to meet the needs of space division multiplexing. The multi-system signal is input from port b of the remote machine, and is divided into two channels of intermediate frequency signals through a splitter; each channel of intermediate frequency signals is subjected to up-conversion processing. For the specific up-conversion processing scheme, please refer to the three-stage mixing part in Figure 3. That is the second part; the signal after up-conversion processing is an LTE radio frequency signal; the two LTE radio frequency signals can be respectively input to the indoor dual-polarized antenna through port 3 and port 4 of the remote machine to realize MIMO.

FIG. 7 is a schematic diagram of uplink signal transmission in an embodiment of the present invention, and its transmission direction is opposite to that of downlink signals. The indoor dual-polarized antenna sends the received two-way LTE radio frequency signals to port 3 and port 4 of the remote machine respectively; the primary frequency conversion part of the remote machine performs down-conversion processing on the LTE radio frequency signal to obtain two-way intermediate frequency signals; The two-way intermediate frequency signals and other system signals pass through the combiner to obtain multi-system signals, and the multi-system signals can be output from port b of the remote machine. The power divider divides the signal into multiple paths to meet the requirements of space division multiplexing. The splitter is divided into LTE intermediate frequency signal and other system signals; the LTE intermediate frequency signal is input from the port a of the near-end machine, and becomes two-way intermediate frequency signal through the splitter, and the three-stage frequency conversion part of the near-end machine performs the intermediate frequency signal The frequency is up-converted to become an LTE system radio frequency signal, and then the two LTE system radio frequency signals are respectively input to the RRU, and the baseband signal is obtained after being processed by the RRU and sent to the BBU.

Fig. 8 is a schematic flow chart of an embodiment of the dual-channel frequency conversion method of the present invention, including:

Step 81: Using the first branch and the second branch to respectively transmit a signal sent to the other end;

Step 82: Using the third branch and the fourth branch to respectively transmit a signal received from the other end;

The composition and structure of the first branch and the second branch are the same;

The composition and structure of the third branch and the fourth branch are the same.

Optionally, using the third branch and the fourth branch to respectively transmit a signal received from the other end includes:

A three-stage frequency conversion method is adopted to respectively transmit one signal received from the other end.

Further, the three-stage frequency conversion method may specifically include:

Performing first filtering processing, first frequency mixing processing, intermediate frequency filtering processing, intermediate frequency amplification processing, second frequency mixing processing, second filtering processing, third frequency mixing processing, third filtering processing and power amplification on the received signal in sequence deal with.

Optionally, using the third branch and the fourth branch to respectively transmit a signal received from the other end may also include:

ALC processing is performed on the signal after the three-stage frequency conversion.

Optionally, the first mixer and the second mixer use the same local oscillator.

Optionally, using the first branch and the second branch to respectively transmit a signal sent to the other end includes:

Mixers and filters are used to transmit the signals sent from one end to the other end respectively.

Further, the adopting the first branch and the second branch to respectively transmit a signal sent to the other end further includes:

A low-noise amplifier is used to process the signal sent to the other end, so that the processed signal is transmitted by a mixer and a filter.

In this embodiment, due to the use of symmetrical frequency conversion and circuit combining technology, the low delay of the two signals can be realized; the uplink part of the near-end machine and the downlink part of the remote machine adopt a three-stage frequency conversion method, which can effectively suppress high-order harmonics and various Spurious clutter interference to achieve higher output frequency stability and spurious suppression performance; by adopting automatic level control at the end of the remote machine, it meets the requirements of MIMO technology for dual-channel signal output power balance.

Those of ordinary skill in the art can understand that all or part of the steps for implementing the above method embodiments can be completed by program instructions and related hardware. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps including the above-mentioned method embodiments; and the aforementioned storage medium includes: ROM, RAM, magnetic disk or optical disk and other various media that can store program codes.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (13)

1. The utility model provides a two-way frequency conversion equipment of indoor distribution system of LTE which characterized in that includes:

a first portion and a second portion;

the first portion includes: a first branch and a second branch;

the second portion includes: a third branch and a fourth branch;

the first branch and the second branch are respectively used for transmitting a signal sent to the other end;

the third branch and the fourth branch are respectively used for transmitting a signal received from the other end;

the first branch and the second branch have the same composition structure;

the third branch and the fourth branch have the same composition structure.

2. The apparatus according to claim 1, wherein the third branch and the fourth branch both adopt a three-stage frequency conversion method.

3. The apparatus of claim 2, wherein the third and fourth branches each comprise:

the first filter, the first mixer, the intermediate frequency filter, the intermediate frequency amplifier, the second mixer, the second filter, the third mixer, the third filter and the power amplifier are sequentially connected in series;

the first filter is used for carrying out first filtering processing on the signal received from the other end;

the first frequency mixer is used for carrying out first frequency conversion processing on the signal subjected to the first filtering processing;

the intermediate frequency filter is used for performing intermediate frequency filtering processing on the signal subjected to the first frequency conversion processing;

the intermediate frequency amplifier is used for performing intermediate frequency amplification processing on the signal subjected to the intermediate frequency filtering processing;

the second frequency mixer is used for carrying out second frequency conversion processing on the signal subjected to the intermediate frequency amplification processing;

the second filter is used for carrying out second filtering processing on the signal subjected to the second frequency conversion processing;

the third mixer is used for carrying out third frequency conversion processing on the signal subjected to the second filtering processing;

the third filter is used for performing third filtering processing on the signal subjected to the third frequency conversion processing;

the power amplifier is used for performing power amplification processing on the signal subjected to the third filtering processing;

the signals after the power amplification processing are respectively sent to a receiving port of the RRU.

4. The apparatus of claim 3, wherein when the apparatus is a remote machine, the third and fourth branches each further comprise:

and the ALC is connected with the power amplifier and is used for carrying out automatic level control processing on the signal after the power amplification processing and then sending the signal to a receiving port of the RRU.

5. The apparatus of claim 3,

the first frequency mixer and the second frequency mixer use the same local oscillator.

6. The apparatus according to any of claims 1-5, wherein the first branch and the second branch each comprise:

the fourth mixer and the fourth filter are sequentially connected in series;

the fourth frequency mixer is used for carrying out fourth frequency conversion processing on the signal sent to the other end;

the fourth filter is used for performing fourth filtering processing on the fourth frequency-conversion processed signal;

and the fourth filtered signal is combined and then sent to the other end.

7. The apparatus of claim 6, wherein when the apparatus is a remote machine, the first and second branches each further comprise:

and the low-noise amplifier is connected with the fourth mixer in series and is used for carrying out low-noise amplification on the signal sent to the other end and then sending the signal to the fourth mixer.

8. An LTE indoor distribution system comprising the apparatus of any of claims 1-7.

9. A double-path frequency conversion method of an LTE indoor distribution system is characterized by comprising the following steps:

respectively transmitting a signal sent to the other end by adopting a first branch and a second branch;

respectively transmitting a signal received from the other end by adopting a third branch and a fourth branch;

the first branch and the second branch have the same composition structure;

the third branch and the fourth branch have the same composition structure.

10. The method of claim 9, wherein said transmitting a signal received from said another end using a third branch and a fourth branch, respectively, comprises:

and respectively transmitting a path of signal received from the other end by adopting a three-stage frequency conversion mode.

11. The method of claim 10, wherein said transmitting a signal received from said another end using a third branch and a fourth branch, respectively, further comprises:

and carrying out ALC processing on the signal subjected to the three-stage frequency conversion.

12. The method according to any one of claims 9-11, wherein said using the first branch and the second branch to transmit a signal sent to the other end separately comprises:

a mixer and a filter are adopted to respectively transmit a signal sent to the other end.

13. The method of claim 12, wherein the using the first branch and the second branch to transmit a signal sent to the other end respectively further comprises:

and processing the signal sent to the other end by using a low noise amplifier so as to transmit the processed signal by using a mixer and a filter.

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