CN111478731A

CN111478731A - Communication system and communication method

Info

Publication number: CN111478731A
Application number: CN201910063331.2A
Authority: CN
Inventors: 沈仕乐; 李国华
Original assignee: Guangzhou Kaixin Communication System Co ltd
Current assignee: Guangzhou Kaixin Communication System Co ltd
Priority date: 2019-01-23
Filing date: 2019-01-23
Publication date: 2020-07-31

Abstract

The present application relates to a communication system and a communication method. The communication system includes: the access unit is used for receiving an initial downlink signal sent by a signal source, converting the initial downlink signal into a downlink interface signal and sending the downlink interface signal to at least one extension unit; the extension unit is connected with the access unit and used for receiving the downlink interface signal, converting the downlink interface signal into a downlink signal of a millimeter wave frequency band and sending the downlink signal of the millimeter wave frequency band to at least one remote unit; and the remote unit is connected with the extension unit and used for receiving the downlink signal of the millimeter wave frequency band, converting the downlink signal of the millimeter wave frequency band into a target downlink radio frequency signal and sending the target downlink radio frequency signal to user equipment. The communication system can realize wide high-quality signal coverage and meet the requirements of 5G or even 6G on a distributed coverage system.

Description

Communication system and communication method

Technical Field

The present application relates to the field of communications technologies, and in particular, to a communication system and a communication method.

Background

The mobile communication technology rapidly evolves from 1G to 4G for large-scale application, and even the development of the subsequent 5G (fifth generation mobile communication technology) and 6G drives the explosive growth of broadband data services such as mobile internet, internet of things and the like, and the high-quality signal coverage in indoor and other data service hot spot areas is particularly urgent.

In order to solve the problem of high-quality signal coverage in hot spot areas in 5G communication systems or subsequent 6G communication systems, in a traditional three-level network architecture coverage mode of an AU (Access Unit ) + EU (Expansion Unit, extension Unit) + RU (remote Unit), the AU adopts a method of radio frequency coupling base station signals, and meanwhile, optical fiber transmission is adopted between the AU and the EU and between the EU and the RU.

However, in practical applications, the RU is usually installed indoors, at the street, or even in the home, and therefore, deployment of the optical fiber causes difficulties in engineering construction and limited application scenarios.

Disclosure of Invention

In view of the above, it is necessary to provide a communication system and a communication method with a wide application range in view of the above technical problems.

In a first aspect, a communication system includes:

the access unit is used for receiving an initial downlink signal sent by a signal source, converting the initial downlink signal into a downlink interface signal and sending the downlink interface signal to at least one extension unit;

the extension unit is connected with the access unit and used for receiving the downlink interface signal, converting the downlink interface signal into a downlink signal of a millimeter wave frequency band and sending the downlink signal of the millimeter wave frequency band to at least one remote unit;

and the remote unit is connected with the extension unit and used for receiving the downlink signal of the millimeter wave frequency band, converting the downlink signal of the millimeter wave frequency band into a target downlink radio frequency signal and sending the target downlink radio frequency signal to user equipment.

In one embodiment, when the access unit is connected to the extension unit optical fiber or network cable, the extension unit includes:

the protocol analysis module is used for receiving the downlink framing signals sent by the access unit and performing de-framing processing on the downlink framing signals to obtain downlink digital signals;

the multi-channel data processing module is used for carrying out channel decomposition on the downlink digital signals to obtain multi-channel downlink digital signals;

the digital-to-analog conversion module is used for performing digital-to-analog conversion on the multi-channel downlink digital signals to obtain multi-channel downlink analog signals with different frequencies;

the first local oscillation signal generating module is used for generating local oscillation signals;

the millimeter wave signal processing module is used for carrying out frequency mixing processing on the multi-channel downlink analog signals according to the multi-channel local oscillator signals to obtain downlink signals of a millimeter wave frequency band;

and the first millimeter wave signal transceiver is used for sending the downlink signal of the millimeter wave frequency band to the remote unit.

In one embodiment, the remote unit includes:

the second millimeter wave signal transceiver is used for receiving the downlink signal of the millimeter wave frequency band sent by the extension unit;

the second local oscillation signal generating module is used for generating local oscillation signals;

the frequency conversion module is used for carrying out frequency mixing processing on the downlink signal of the millimeter wave frequency band according to the local oscillator signal to obtain a downlink intermediate frequency signal;

the frequency mixing module is used for dividing the downlink intermediate frequency signal into a plurality of paths of downlink intermediate frequency signals and carrying out frequency mixing processing on the plurality of paths of downlink intermediate frequency signals according to a plurality of paths of local oscillator signals to obtain a plurality of paths of target downlink radio frequency signals of a target frequency; the multiple paths of downlink intermediate frequency signals respectively correspond to a plurality of preset frequencies, and the multiple paths of local oscillator signals correspond to the preset frequencies one by one;

and the radio frequency signal transceiver is used for transmitting the multi-path target downlink radio frequency signals to user equipment.

In one embodiment, the access unit is further configured to add a first synchronization signal to the downlink interface signal; the first synchronization signal is used for synchronization between the access unit and the extension unit; the extension unit is further configured to analyze the first synchronization signal from the downlink interface signal, and generate a clock signal and a local oscillator signal of the extension unit according to the first synchronization signal.

In one embodiment, the extension unit is further configured to generate a second synchronization signal, convert the second synchronization signal into a continuous wave signal, and send the continuous wave signal to the remote unit; the second synchronization signal is used for synchronization between the extension unit and the remote unit; the remote unit is further configured to extract the second synchronization signal from the continuous wave signal, and generate a clock signal and a local oscillator signal of the remote unit according to the second synchronization signal.

In one embodiment, the second synchronization signal is a specific frequency signal or a global positioning system GPS signal.

In one of the embodiments the access unit is radio frequency connected to the active antenna unit AAU and/or the access unit is connected to the concentration/distribution unit CU/DU optical fiber or network cable.

In a second aspect, a communication system includes:

the remote unit is used for receiving an uplink radio frequency signal sent by user equipment, converting the uplink radio frequency signal into an uplink signal of a millimeter wave frequency band, and sending the uplink signal of the millimeter wave frequency band to the extension unit;

the extension unit is connected with at least one remote unit and used for receiving the uplink signal of the millimeter wave frequency band, converting the uplink signal of the millimeter wave frequency band into an uplink interface signal and sending the uplink interface signal to the access unit;

and the access unit is connected with at least one expansion unit and used for receiving the uplink interface signal, converting the uplink interface signal into a target uplink signal and sending the target uplink signal to a signal source.

In one embodiment, the remote unit includes:

the radio frequency signal transceiver is used for receiving a plurality of paths of uplink radio frequency signals sent by the user equipment;

the frequency mixing module is used for carrying out frequency mixing processing on the multi-path uplink radio frequency signals according to the multi-path local oscillator signals to obtain multi-path uplink preset intermediate frequency signals and combining the multi-path uplink preset intermediate frequency signals into uplink intermediate frequency signals; the multi-path uplink preset intermediate frequency signals respectively correspond to a plurality of preset frequencies, and the multi-path local oscillator signals correspond to the preset frequencies one to one;

the frequency conversion module is used for carrying out frequency mixing processing on the uplink intermediate frequency signal according to the local oscillation signal to obtain an uplink signal of a millimeter wave frequency band;

and the second millimeter wave signal transceiver is used for sending the uplink signal of the millimeter wave frequency band to the extension unit.

the first millimeter wave signal transceiver is used for receiving an uplink signal of a millimeter wave frequency band sent by the remote unit;

the millimeter wave signal processing module is used for dividing the uplink signal of the millimeter wave frequency band into a plurality of paths of uplink signals of the millimeter wave frequency band, and carrying out frequency mixing processing on the plurality of paths of uplink signals of the millimeter wave frequency band according to a plurality of paths of local oscillator signals to obtain a plurality of paths of intermediate frequency analog signals;

the digital-to-analog conversion module is used for carrying out analog-to-digital conversion on the multi-channel intermediate frequency analog signals to obtain multi-channel uplink digital signals;

and the protocol analysis module is used for framing the multi-path uplink digital signals to obtain uplink framing signals and sending the uplink framing signals to the access unit.

In a third aspect, a method of communication, the method comprising:

receiving an initial downlink signal sent by a signal source through an access unit, converting the initial downlink signal into a downlink interface signal, and sending the downlink interface signal to at least one extension unit;

receiving the downlink interface signal through the extension unit, converting the downlink interface signal into a downlink signal of a millimeter wave frequency band, and sending the downlink signal of the millimeter wave frequency band to at least one remote unit;

and receiving the downlink signal of the millimeter wave frequency band through the remote unit, converting the downlink signal of the millimeter wave frequency band into a target downlink radio frequency signal, and sending the target downlink radio frequency signal to user equipment.

In one embodiment, when the access unit is connected to the extension unit through an optical fiber or a network cable, the receiving, by the extension unit, the downlink interface signal, converting the downlink interface signal into a downlink signal in a millimeter wave band, and sending the downlink signal in the millimeter wave band to at least one remote unit includes:

receiving a downlink framing signal sent by the access unit, and performing de-framing processing on the downlink framing signal to obtain a downlink digital signal;

performing channel decomposition on the downlink digital signals to obtain a plurality of channels of downlink digital signals;

performing digital-to-analog conversion on the multi-channel downlink digital signals to obtain multi-channel downlink analog signals with different frequencies;

generating a local oscillation signal;

carrying out frequency mixing processing on the multi-channel downlink analog signals according to the multi-channel local oscillator signals to obtain downlink signals of a millimeter wave frequency band;

and sending the downlink signal of the millimeter wave frequency band to the remote unit.

In one embodiment, the receiving, by the remote unit, the downlink signal in the millimeter wave frequency band, converting the downlink signal in the millimeter wave frequency band into a target downlink radio frequency signal, and sending the target downlink radio frequency signal to the user equipment includes:

receiving a downlink signal of a millimeter wave frequency band sent by the extension unit;

generating a local oscillation signal;

performing frequency mixing processing on the downlink signal of the millimeter wave frequency band according to the local oscillator signal to obtain a downlink intermediate frequency signal;

the downlink intermediate frequency signal is divided into a plurality of paths of downlink intermediate frequency signals, and the plurality of paths of downlink intermediate frequency signals are subjected to frequency mixing processing according to a plurality of paths of local oscillator signals to obtain a plurality of paths of target downlink radio frequency signals of a target frequency; the multiple paths of downlink intermediate frequency signals respectively correspond to a plurality of preset frequencies, and the multiple paths of local oscillator signals correspond to the preset frequencies one by one;

and sending the multi-path target downlink radio frequency signals to user equipment.

In one embodiment, the method further comprises:

adding a first synchronization signal to the downlink interface signal through the access unit; the first synchronization signal is used for synchronization between the access unit and the extension unit;

and analyzing the first synchronous signal from the downlink interface signal through the extension unit, and generating a clock signal and a local oscillator signal of the extension unit according to the first synchronous signal.

In one embodiment, the method further comprises:

generating a second synchronous signal through the expansion unit, converting the second synchronous signal into a continuous wave signal, and sending the continuous wave signal to the remote unit; the second synchronization signal is used for synchronization between the extension unit and the remote unit;

and extracting the second synchronous signal from the continuous wave signal through the remote unit, and generating a clock signal and a local oscillator signal of the remote unit according to the second synchronous signal.

In one embodiment, the second synchronization signal is a specific frequency signal or a GPS signal.

In one embodiment, the receiving, by the access unit, an initial downlink signal sent by a signal source includes:

receiving an initial downlink radio frequency signal sent by an AAU through the access unit;

and/or the presence of a gas in the gas,

and receiving an initial downlink framing signal sent by the CU/DU through an optical fiber or a network cable through the access unit.

In a fourth aspect, a method of communication, the method comprising:

receiving an uplink radio frequency signal sent by user equipment through a remote unit, converting the uplink radio frequency signal into an uplink signal of a millimeter wave frequency band, and sending the uplink signal of the millimeter wave frequency band to an extension unit;

receiving the uplink signal of the millimeter wave frequency band through the extension unit, converting the uplink signal of the millimeter wave frequency band into an uplink interface signal, and sending the uplink interface signal to the access unit;

and receiving the uplink interface signal through the access unit, converting the uplink interface signal into a target uplink signal, and sending the target uplink signal to a signal source.

In one embodiment, the receiving, by the remote unit, an uplink radio frequency signal sent by a user equipment, converting the uplink radio frequency signal into an uplink signal in a millimeter wave frequency band, and sending the uplink signal in the millimeter wave frequency band to the extension unit includes:

receiving a plurality of paths of uplink radio frequency signals sent by user equipment;

generating a local oscillation signal;

mixing the multiple uplink radio frequency signals according to the multiple local oscillator signals to obtain multiple uplink preset intermediate frequency signals, and combining the multiple uplink preset intermediate frequency signals into uplink intermediate frequency signals; the multi-path uplink preset intermediate frequency signals respectively correspond to a plurality of preset frequencies, and the multi-path local oscillator signals correspond to the preset frequencies one to one;

performing frequency mixing processing on the uplink intermediate frequency signal according to the local oscillation signal to obtain an uplink signal of a millimeter wave frequency band;

and sending the uplink signal of the millimeter wave frequency band to the extension unit.

In one embodiment, when the access unit is connected to the extension unit through an optical fiber or a network cable, the receiving, by the extension unit, the uplink signal in the millimeter wave band, converting the uplink signal in the millimeter wave band into an uplink interface signal, and sending the uplink interface signal to the access unit includes:

receiving an uplink signal of a millimeter wave frequency band sent by the remote unit;

generating a local oscillation signal;

dividing the uplink signal of the millimeter wave frequency band into multiple paths of uplink signals of the millimeter wave frequency band, and performing frequency mixing processing on the multiple paths of uplink signals of the millimeter wave frequency band according to multiple paths of local oscillator signals to obtain multiple paths of intermediate frequency analog signals;

performing analog-to-digital conversion on the multiple paths of intermediate frequency analog signals to obtain multiple paths of uplink digital signals;

and framing the plurality of paths of uplink digital signals to obtain uplink framing signals, and sending the uplink framing signals to the access unit.

In the communication system and the communication method, in the downlink process, the communication system can receive an initial downlink signal sent by a signal source through an access unit, convert the initial downlink signal into a downlink interface signal and send the downlink interface signal to at least one extension unit; then, the extension unit converts the downlink interface signal into a downlink signal of a millimeter wave frequency band, and sends the downlink signal to at least one remote unit; and finally, the remote unit converts the downlink signal of the millimeter wave frequency band into a target downlink radio frequency signal and sends the target downlink radio frequency signal to the user equipment, so that the problem of limited scenes when optical fiber communication is adopted between the extension unit and the remote unit is avoided, the problem of low transmission performance when communication such as network cables is adopted between the extension unit and the remote unit is also avoided, wide high-quality signal coverage can be realized, and the requirements of 5G or even 6G on a distributed coverage system are met.

Drawings

FIG. 1 is a diagram of an exemplary communications system;

FIG. 2 is a block diagram of a communication system in one embodiment;

FIG. 3a is a schematic diagram of a communication system and signal sources in one embodiment;

FIG. 3b is a schematic diagram of 4 RF signals according to an embodiment;

FIG. 4a is a block diagram of the structure of an expansion unit in one embodiment;

FIG. 4b is a schematic diagram of the synthesis and mixing of 4 downstream analog signals in one embodiment;

FIG. 4c is a block diagram of the remote unit in one embodiment;

FIG. 5 is a flow diagram illustrating a synchronization method in one embodiment;

FIG. 6 is a block diagram of a communication system in one embodiment;

FIG. 7 is a flow diagram illustrating a method of communication in one embodiment;

FIG. 8 is a flow diagram illustrating a method of communication in one embodiment;

fig. 9 is a schematic diagram of uplink and downlink flow of a communication method in an embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

The communication system provided by the application can be applied to the application environment shown in fig. 1. The signal source communicates with at least one communication system, and the communication system communicates with at least one user equipment to realize indirect communication between the signal source and the user equipment. The signal source may be, but is not limited to, a base station in a communication system of 2G, 3G, 4G, or the like, an active antenna unit AAU in 5G, even 6G, or a centralized/distributed unit CU/DU, or the like, or a baseband processing unit of another type of communication system; the user equipment can be, but is not limited to, various mobile phones, portable wearable devices, computer equipment and other terminals with wireless transceiving functions.

In one embodiment, as shown in fig. 2, there is provided a communication system, which may include:

the access unit 11 is configured to receive an initial downlink signal sent by a signal source, convert the initial downlink signal into a downlink interface signal, and send the downlink interface signal to at least one extension unit 12;

the extension unit 12 is connected to the access unit, and configured to receive the downlink interface signal, convert the downlink interface signal into a downlink signal in a millimeter wave frequency band, and send the downlink signal in the millimeter wave frequency band to at least one remote unit 13;

the remote unit 13 is connected to the extension unit, and configured to receive the downlink signal in the millimeter wave frequency band, convert the downlink signal in the millimeter wave frequency band into a target downlink radio frequency signal, and send the target downlink radio frequency signal to the user equipment.

The access unit 11 is connected to one or more expansion units 12, and the connection mode may be, but is not limited to, wired communication connection such as optical fiber, network cable, and the like, and may also be wireless communication connection through radio frequency signals; generally, signal splitting and relaying are performed by a plurality of expansion units to achieve large-area signal coverage, so that at least one expansion unit can be arranged in each signal hot spot area, specifically, the actual signal requirement is related to the service processing capacity of the expansion unit.

Similarly, the extension unit 12 may be connected to one or more remote units 13, may be disposed in each sub-area of each signal hot spot area, and may be disposed in an indoor area, a mall area, an underground space, or the like, so as to shorten a communication distance with the user equipment. It should be emphasized that, in this embodiment, the extension unit and the remote unit may perform wireless communication through millimeter wave signals; compared with optical fiber transmission, the extension unit and the remote unit only need to be respectively provided with corresponding millimeter wave signal transceivers, such as millimeter wave antennas, at two ends, and do not need to be provided with optical fibers, so that the problems of various obstacles and limited application scenes caused by the arrangement of the optical fibers are solved; compared with the network transmission (transmission rate of 10-60MHz), the millimeter wave is generally 1-10 mm electromagnetic wave, the frequency can be 27-300GHz, for example 28GHz, the bandwidth is extremely high, and the requirement of high-quality communication with high transmission rate can be met.

This embodiment mainly describes a downlink procedure in a communication system. Based on the connection relationship between the access unit and the extension unit, when the access unit and the extension unit communicate with each other, the corresponding protocol needs to be satisfied, so that the access unit needs to convert the initial downlink signal sent by the signal source into a downlink interface signal conforming to the protocol; for example, when connected by an optical fiber, a Common Public Radio Interface (CPRI) protocol needs to be satisfied; when connected by a network cable, the ethernet protocol and the like need to be satisfied.

It is understood that a plurality of extension units may be in a parallel relationship, a cascade relationship to realize signal coverage at a longer distance, or a combination of parallel and cascade. The extension unit may convert a downlink interface signal sent by the access unit into a downlink signal in a millimeter wave frequency band through up-conversion processing, and send the downlink signal to at least one remote unit, or send the downlink signal to at least one cascaded extension unit of the extension unit, and finally send the downlink signal to the remote unit in a millimeter wave form. Of course, the above-mentioned millimeter wave frequency band signal transmission method may adopt various multiplexing methods such as time division multiple access, code division multiple access, frequency division multiple access, orthogonal frequency division multiplexing, etc., and this embodiment does not limit this.

After receiving the downlink signal of the millimeter wave frequency band sent by the extension unit, the remote unit can convert the downlink signal of the millimeter wave frequency band into a target downlink radio frequency signal through down-conversion processing, and send the target downlink radio frequency signal to the user equipment, so that a complete downlink process is realized. It will be appreciated that the remote unit may be provided with a radio frequency signal transceiver, such as a coverage antenna, which may communicate wirelessly with the user equipment.

In the communication system provided by this embodiment, an initial downlink signal sent by a signal source may be received by an access unit, and the initial downlink signal is converted into a downlink interface signal and sent to at least one extension unit; then, the extension unit converts the downlink interface signal into a downlink signal of a millimeter wave frequency band, and sends the downlink signal to at least one remote unit; and finally, the remote unit converts the downlink signal of the millimeter wave frequency band into a target downlink radio frequency signal and sends the target downlink radio frequency signal to the user equipment, so that the problem of limited scenes when optical fiber communication is adopted between the extension unit and the remote unit is avoided, the problem of low transmission performance when communication such as network cables is adopted between the extension unit and the remote unit is also avoided, wide high-quality signal coverage can be realized, and the requirements of 5G or even 6G on a distributed coverage system are met.

Optionally, referring to fig. 3a, the access unit 11 is connected to the AAU21 via radio frequency, and/or the access unit 11 is connected to the CU/DU unit 22 via optical fiber or network cable; the AAU and CU/DU may be 5G signal sources or signal sources under other communication standards. The AAU is a combination of a part of a physical layer of an original BBU (baseband processing Unit) and an original RRU, and may be connected to a CU/DU by an optical fiber or a network cable, and may communicate with the CU/DU by using an enhanced-CPRI (enhanced common public radio interface); the CU is a non-real-time part of the original BBU and is responsible for processing non-real-time protocols and services; the DU is the rest of the original BBU and is responsible for processing physical layer protocols and real-time services. In this embodiment, the access unit may include a radio frequency signal transceiver, communicate with the AAU through a radio frequency signal, and receive an initial downlink signal in the form of a radio frequency signal sent by the AAU, and the access unit may perform frequency conversion and analog-to-digital conversion on the initial downlink signal to obtain a digital baseband signal; the access unit may also include an optical port or a network port, receives an initial downlink signal in the form of a digital signal sent by the CU/DU, and obtains a digital baseband signal by analyzing the initial downlink signal.

The traditional way of communicating with signal sources through radio frequency coupling results in the capacity of the whole coverage network (communication system) being limited by the capacity of the accessed signal sources; the communication mode between the signal source and the access unit in the embodiment does not have the problems, and the capacity of the whole coverage network can be improved; in addition, the multiple communication modes between the signal source and the access unit provided by the embodiment can facilitate the selection of a proper communication mode according to a scene, and can also improve the disaster tolerance capability.

Referring to fig. 3a, in order to support MIMO (Multiple-Input Multiple-Output), taking 4T4R (4 transmit and 4 receive) as an example, the AAU and the access unit may communicate with each other through four paths of radio frequency signals, that is, the initial downlink signal is a 4-path downlink radio frequency signal; illustratively, referring to fig. 3b, the 4 rf signals are 4 MIMO signals, the frequency is 3.5GHz, the center frequency is 3450MHz, and four channels have the same frequency. Accordingly, the radio frequency signal transceiver in the remote units needs to support at least 4T4R, for example, each remote unit may be provided with at least 4 coverage antennas. In the present embodiment, a detailed description will be given by taking a scenario in which the AAU and the access unit communicate via a 4-channel radio frequency signal as an example, but the present embodiment may also be used in other scenarios or with other channel numbers.

In one embodiment, referring to fig. 4a, a block diagram of an extension unit 12 is shown, wherein an access unit and an extension unit are connected by an optical fiber or a network cable, and the extension unit 12 may include: a protocol analysis module 121, configured to receive the downlink framing signal sent by the access unit, and perform a deframing process on the downlink framing signal to obtain a downlink digital signal; a multi-channel data processing module 122, configured to perform channel decomposition on the downlink digital signal to obtain multiple downlink digital signals; the digital-to-analog conversion module 123 is configured to perform digital-to-analog conversion on the multiple downlink digital signals to obtain multiple downlink analog signals with different frequencies; a first local oscillation signal generating module 124, configured to generate a local oscillation signal; the millimeter wave signal processing module 125 is configured to perform frequency mixing processing on the multiple downlink analog signals according to the multiple local oscillator signals to obtain downlink signals in a millimeter wave frequency band; the first millimeter wave signal transceiver 126 is configured to send the downlink signal in the millimeter wave frequency band to the remote unit.

Specifically, after converting an initial downlink signal sent by a signal source into a digital baseband signal, the access unit may encapsulate the digital baseband signal into a downlink framing signal according to a CPRI protocol, and transmit the downlink framing signal to the extension unit through a digital optical fiber or a network cable; preferably, the digital fiber rate is 40Gbps (bit rate); an access unit may transmit to 8 extension units. The protocol analysis module 121 in the extension unit 12 may analyze, that is, perform deframing processing on the downlink framing signal to obtain a downlink digital signal; when the access unit is connected to the extension unit through an optical fiber, the protocol analysis module 121 may convert an optical signal sent by the access unit into a downlink digital signal; the multi-channel data processing module 122 is connected to the protocol analyzing module 121, and can perform channel decomposition on the downlink digital signals to obtain 4 downlink digital signals; the digital-to-analog conversion module 123 is connected to the multi-channel data processing module 122, and is configured to perform digital-to-analog conversion on the 4 downlink digital signals to obtain 4 downlink analog signals with different frequencies, so as to facilitate subsequent combining, where specifically, a preset frequency interval value is satisfied between the 4 downlink analog signals; the millimeter wave signal processing module 125 is connected to the digital-to-analog conversion module 123, and may perform frequency mixing processing on the 4 downlink analog signals through 4 high-frequency local oscillator signals to obtain 4 higher-frequency millimeter wave signals, that is, modulate the 4 downlink analog signals onto a millimeter wave carrier, perform frequency combining to obtain downlink signals in a millimeter wave frequency band, and transmit the downlink signals through the first millimeter wave signal transceiver 126; the frequency of the downlink signal of the millimeter wave frequency band may be 28 GHz.

As shown in fig. 4a, the millimeter wave signal processing module 125 may include: 4 paths of downlink frequency mixing processing links and a branching and combining device; each downlink mixing processing link is connected with the branching and branching device, and the method may include: the front filter circuit is used for carrying out band-pass filtering and filtering out clutter generated in the digital-to-analog conversion process of each downlink analog signal; the mixer circuit is used for carrying out mixing processing on each path of downlink analog signals according to each path of local oscillator signals to obtain each path of millimeter wave signals; the post-filtering circuit is used for carrying out band-pass filtering and filtering out clutter generated in the frequency mixing processing process of each path of millimeter wave signal; and the downlink amplifying circuit is used for amplifying each path of millimeter wave signal.

It can be understood that, the frequencies of the local oscillator signals of the extension unit may be the same, so in addition to the processing manner of performing frequency mixing processing and then combining on the downlink analog signals of the channels, as shown in fig. 4b, the extension unit may also perform frequency mixing processing on the downlink analog signals of the channels first and then perform frequency mixing processing; the 4 downlink analog signals with frequencies of f1 to f4 may be combined into a downlink analog signal with a center frequency point fc, and then the downlink signal with a millimeter wave frequency band with a center frequency point 28GHz is obtained through local oscillator signal mixing processing, where the frequency of the local oscillator signal may be (28 GHz-fc).

Referring to fig. 4c, a block diagram of a remote unit 13 is shown, where the remote unit 13 may include: a second millimeter wave signal transceiver 131, configured to receive a downlink signal in a millimeter wave frequency band sent by the extension unit; a second local oscillation signal generating module 132, configured to generate a local oscillation signal; the frequency conversion module 133 is configured to perform frequency mixing processing on the downlink signal in the millimeter wave frequency band according to the local oscillator signal to obtain a downlink intermediate frequency signal; the frequency mixing module 134 is configured to divide the downlink intermediate frequency signal into multiple downlink intermediate frequency signals, and perform frequency mixing processing on the multiple downlink intermediate frequency signals according to multiple local oscillator signals to obtain multiple target downlink radio frequency signals at a target frequency; the multiple paths of downlink intermediate frequency signals respectively correspond to a plurality of preset frequencies, and the multiple paths of local oscillator signals correspond to the preset frequencies one by one; a radio frequency signal transceiver 135, configured to send the multiple downlink target radio frequency signals to the user equipment.

Specifically, the second millimeter wave signal transceiver 131 of the remote unit 13 may receive the downlink signal in the millimeter wave band transmitted by the first millimeter wave signal transceiver of the extension unit; the frequency conversion module 133 is connected to the second millimeter wave signal transceiver 131, and may perform frequency mixing processing on the downlink signal in the millimeter wave frequency band according to the local oscillator signal to obtain a downlink intermediate frequency signal, which is convenient for signal processing, and preferably, the downlink intermediate frequency signal is 2 GHz; the frequency mixing module 134 is connected to the frequency conversion module 133, and is capable of splitting the downlink intermediate frequency signal into 4 downlink intermediate frequency signals, and performing frequency mixing processing on the 4 downlink intermediate frequency signals according to the 4 local oscillator signals to obtain 4 target downlink radio frequency signals of a target frequency, and transmitting the target downlink radio frequency signals through the radio frequency signal transceiver 135. It should be noted that, in this embodiment, a preset frequency interval value exists between the 4 downlink analog signals processed by the digital-to-analog conversion module 123 in the extension unit, and correspondingly, the preset frequency interval value exists between the 4 downlink intermediate-frequency signals, so four local oscillator signals need to be generated according to the preset frequency interval value, so that the 4 target downlink radio-frequency signals obtained after the frequency mixing processing have the same frequency and are the target frequency. For example, the target frequency may be 3.5GHz, the intermediate frequency interval may be 75MHz, the frequencies of the 4 downlink intermediate frequency signals may be 1.925GHz, 2GHz, 2.075GHz, and 2.15GHz, and the frequencies of the 4 local oscillator signals are 1.575, 1.50, 1.425, and 1.35GHz, respectively.

As shown in fig. 4c, the frequency mixing module 134 may include: the circuit breaker and the 4-path downlink frequency mixing processing link; each downlink mixing processing link is connected with the branching and branching device, and the method may include: the front filter circuit is used for carrying out band-pass filtering, filtering clutter generated in the mixing processing process of each path of downlink intermediate frequency signals, and carrying out frequency selection according to the preset intermediate frequency of each path to obtain downlink intermediate frequency signals conforming to each path; the mixing circuit is used for carrying out mixing processing on each path of downlink intermediate frequency signals according to each path of local oscillator signals to obtain target downlink radio frequency signals of each path of target frequency; the post-filtering circuit is used for carrying out band-pass filtering and filtering out clutter generated by each path of target downlink radio frequency signals in the frequency mixing processing process; and the downlink amplifying circuit is used for amplifying each path of target downlink radio frequency signals.

Therefore, the communication system of the embodiment can perform multi-channel data processing, improve data transmission capability, and provide high-quality signal coverage of MIMO.

In one embodiment, as shown with reference to fig. 4a and 5, the present embodiment also relates to synchronization between the access unit and the extension unit, which is mainly frequency synchronization in clock synchronization. The access unit 11 is further configured to add a first synchronization signal to the downlink interface signal; the first synchronization signal is used for synchronization between the access unit 11 and the extension unit 12; the extension unit 12 is further configured to parse the first synchronization signal from the downlink interface signal, and generate a clock signal and a local oscillator signal of the extension unit according to the first synchronization signal. Specifically, the access unit may add baseband synchronization information (a first synchronization signal) to a downlink framing signal conforming to a CPRI protocol, the extension unit may analyze the downlink framing signal according to the CPRI protocol to obtain a downlink digital signal and obtain the first synchronization signal, and the extension unit 12 may generate each local oscillation signal in the extension unit by using the first synchronization signal as a reference signal (a clock signal) through the first local oscillation signal generating module 124.

Further, referring to fig. 4c and 5, the present embodiment also relates to synchronization between the extension unit and the remote unit. The extension unit 12 is further configured to generate a second synchronization signal, convert the second synchronization signal into a continuous wave signal, and send the continuous wave signal to the remote unit 13; the second synchronization signal is used for synchronization between the extension unit 12 and the remote unit 13; the remote unit 13 is further configured to extract the second synchronization signal from the continuous wave signal, and generate a clock signal and a local oscillator signal of the remote unit according to the second synchronization signal. Specifically, the extension unit may generate a local continuous wave signal according to the first synchronization signal, then modulate to a specific frequency, obtain a specific frequency signal as a second synchronization signal, and transmit the specific frequency signal in the form of a continuous wave signal (low-frequency signal) through the reference signal antenna; the specific frequency used for synchronization of different extension units can be different, and the specific frequency can be between 200MHz and 800 MHz; of course, the extension unit may also acquire a GPS signal through the GPS synchronization unit, and transmit the GPS signal as a second synchronization signal through a GPS antenna (also a reference signal antenna) in the form of a continuous wave signal. The remote unit 13 may receive the continuous wave signal sent by the extension unit through its own reference signal antenna and demodulate a second synchronization signal therefrom, and the second synchronization signal may be used as a reference signal (clock signal) to generate each local oscillation signal in the remote unit through the second local oscillation signal generating module 132, so as to avoid frequency difference between the obtained downlink radio frequency signals of each path of target. It should be noted that, since the GPS signal is generally more stable and accurate, the remote unit may determine whether the GPS signal transmitted by the extension unit is received, and if so, preferably, the GPS signal is used as the second synchronization signal, and if not, the specific frequency signal is used as the second synchronization signal.

In the communication system of this embodiment, the synchronization between the access unit and the extension unit may be achieved through the first synchronization signal, and the synchronization between the extension unit and the remote unit may be achieved through the second synchronization signal, so as to avoid frequency difference between the obtained target downlink radio frequency signals, thereby ensuring normal communication with the user equipment.

In one embodiment, as shown in fig. 6, there is provided a communication system including:

the remote unit 61 is configured to receive an uplink radio frequency signal sent by user equipment, convert the uplink radio frequency signal into an uplink signal in a millimeter wave frequency band, and send the uplink signal in the millimeter wave frequency band to the extension unit;

the extension unit 62 is connected to at least one of the remote units, and configured to receive an uplink signal in the millimeter wave frequency band, convert the uplink signal in the millimeter wave frequency band into an uplink interface signal, and send the uplink interface signal to an access unit;

the access unit 63 is connected to at least one of the extension units, and configured to receive the uplink interface signal, convert the uplink interface signal into a target uplink signal, and send the target uplink signal to a signal source.

This embodiment mainly describes an uplink procedure in a communication system. Specifically, the remote unit may convert the uplink radio frequency signal into an uplink signal in a millimeter wave frequency band, and send the uplink signal in the millimeter wave frequency band to the extension unit, so as to implement millimeter wave signal transmission between the remote unit and the extension unit. It can be understood that, the remote unit may implement a complete uplink process by receiving an uplink radio frequency signal sent by the user equipment, and returning the uplink radio frequency signal to a signal source, such as an AAU unit or a CU/DU unit, through a reverse process of the uplink process; therefore, the specific description in the uplink process may refer to the description in the downlink process, and is not described herein again.

In the communication system provided in this embodiment, an uplink radio frequency signal sent by a user equipment may be received by a remote unit, and the uplink radio frequency signal is converted into an uplink signal in a millimeter wave frequency band and sent to an extension unit; then, converting the uplink signal of the millimeter wave frequency band into an uplink interface signal through the extension unit, and sending the uplink interface signal to the access unit; finally, the uplink interface signal is converted into a target uplink signal through the access unit, and the target uplink signal is sent to a signal source; therefore, the problem of limited scenes when optical fiber communication is adopted between the extension unit and the remote unit is avoided, the problem of low transmission performance when communication such as network cables is adopted between the extension unit and the remote unit is also avoided, wide high-quality signal coverage can be realized, and the requirements of 5G or even 6G on a distributed coverage system are met.

Optionally, the remote unit may specifically include: the radio frequency signal transceiver is used for receiving a plurality of paths of uplink radio frequency signals sent by the user equipment; the second local oscillation signal generating module is used for generating local oscillation signals; the frequency mixing module is used for carrying out frequency mixing processing on the multi-path uplink radio frequency signals according to the multi-path local oscillator signals to obtain multi-path uplink preset intermediate frequency signals and combining the multi-path uplink preset intermediate frequency signals into uplink intermediate frequency signals; the multi-path uplink preset intermediate frequency signals respectively correspond to a plurality of preset frequencies, and the multi-path local oscillator signals correspond to the preset frequencies one to one; the frequency conversion module is used for carrying out frequency mixing processing on the uplink intermediate frequency signal according to the local oscillation signal to obtain an uplink signal of a millimeter wave frequency band; and the second millimeter wave signal transceiver is used for sending the uplink signal of the millimeter wave frequency band to the extension unit.

Optionally, when the access unit is connected to the extension unit optical fiber or network cable, the extension unit includes: the first millimeter wave signal transceiver is used for receiving an uplink signal of a millimeter wave frequency band sent by the remote unit; the first local oscillation signal generating module is used for generating local oscillation signals; the millimeter wave signal processing module is used for dividing the uplink signal of the millimeter wave frequency band into a plurality of paths of uplink signals of the millimeter wave frequency band, and carrying out frequency mixing processing on the plurality of paths of uplink signals of the millimeter wave frequency band according to a plurality of paths of local oscillator signals to obtain a plurality of paths of intermediate frequency analog signals; the digital-to-analog conversion module is used for carrying out analog-to-digital conversion on the multi-channel intermediate frequency analog signals to obtain multi-channel uplink digital signals; and the protocol analysis module is used for framing the multi-path uplink digital signals to obtain uplink framing signals and sending the uplink framing signals to the access unit.

The communication system of the embodiment can perform multi-channel data processing, improve data transmission capability and provide high-quality signal coverage of MIMO.

It should be noted that, in the uplink process, synchronization may be implemented in a manner inverse to the synchronization in the uplink process. For example, the remote unit may generate a third synchronization signal with a certain frequency or use a GPS signal as the third synchronization signal, and send the third synchronization signal to the extension unit through the reference antenna, where the third synchronization signal is used to implement synchronization between the extension unit and the access unit; accordingly, the extension unit may generate a fourth synchronization signal of another specific frequency according to the third synchronization signal or use the GPS signal as the fourth synchronization signal, and add the fourth synchronization signal to the uplink interface signal sent to the access unit, where the fourth synchronization signal is used to achieve synchronization between the extension unit and the access unit.

It can be understood that each module in the remote unit, the extension unit, and the access unit in the downlink process can implement each function in the downlink process, and can also implement the function of each corresponding module in the uplink process; the specific description of each module in the remote unit, the extension unit, and the access unit in the uplink process may refer to the specific description of each module in the remote unit, the extension unit, and the access unit in the downlink process, and fig. 2, fig. 3a, fig. 3b, fig. 4a, fig. 4b, fig. 4c, and fig. 5.

In an embodiment, referring to fig. 7, a communication method is provided, which relates to a downlink process, and the method may specifically include:

s701, receiving an initial downlink signal sent by a signal source through an access unit, converting the initial downlink signal into a downlink interface signal, and sending the downlink interface signal to at least one extension unit;

s702, receiving the downlink interface signal through the extension unit, converting the downlink interface signal into a downlink signal in a millimeter wave band, and sending the downlink signal in the millimeter wave band to at least one remote unit;

and S703, receiving the downlink signal of the millimeter wave frequency band through the remote unit, converting the downlink signal of the millimeter wave frequency band into a target downlink radio frequency signal, and sending the target downlink radio frequency signal to user equipment.

Optionally, when the access unit is connected to the extension unit through an optical fiber or a network cable, the S702 may include: receiving a downlink framing signal sent by the access unit, and performing de-framing processing on the downlink framing signal to obtain a downlink digital signal; performing channel decomposition on the downlink digital signals to obtain a plurality of channels of downlink digital signals; performing digital-to-analog conversion on the multi-channel downlink digital signals to obtain multi-channel downlink analog signals with different frequencies; generating a local oscillation signal; carrying out frequency mixing processing on the multi-channel downlink analog signals according to the multi-channel local oscillator signals to obtain downlink signals of a millimeter wave frequency band; and sending the downlink signal of the millimeter wave frequency band to the remote unit.

Optionally, the S703 may include: receiving a downlink signal of a millimeter wave frequency band sent by the extension unit; generating a local oscillation signal; performing frequency mixing processing on the downlink signal of the millimeter wave frequency band according to the local oscillator signal to obtain a downlink intermediate frequency signal; the downlink intermediate frequency signal is divided into a plurality of paths of downlink intermediate frequency signals, and the plurality of paths of downlink intermediate frequency signals are subjected to frequency mixing processing according to a plurality of paths of local oscillator signals to obtain a plurality of paths of target downlink radio frequency signals of a target frequency; the multiple paths of downlink intermediate frequency signals respectively correspond to a plurality of preset frequencies, and the multiple paths of local oscillator signals correspond to the preset frequencies one by one; and sending the multi-path target downlink radio frequency signals to user equipment.

Optionally, the method further comprises: adding a first synchronization signal to the downlink interface signal through the access unit; the first synchronization signal is used for synchronization between the access unit and the extension unit; and analyzing the first synchronous signal from the downlink interface signal through the extension unit, and generating a clock signal and a local oscillator signal of the extension unit according to the first synchronous signal.

Optionally, the method further comprises: generating a second synchronous signal through the expansion unit, converting the second synchronous signal into a continuous wave signal, and sending the continuous wave signal to the remote unit; the second synchronization signal is used for synchronization between the extension unit and the remote unit; and extracting the second synchronous signal from the continuous wave signal through the remote unit, and generating a clock signal and a local oscillator signal of the remote unit according to the second synchronous signal.

Optionally, the second synchronization signal is a specific frequency signal or a GPS signal.

Optionally, the receiving, by the access unit, an initial downlink signal sent by a signal source includes: receiving an initial downlink radio frequency signal sent by an AAU through the access unit; and/or receiving an initial downlink framing signal sent by the CU/DU through an optical fiber or a network cable through the access unit.

In an embodiment, referring to fig. 8, a communication method is provided, which relates to an uplink process, and the method may specifically include:

s801, receiving an uplink radio frequency signal sent by user equipment through a remote unit, converting the uplink radio frequency signal into an uplink signal of a millimeter wave frequency band, and sending the uplink signal of the millimeter wave frequency band to an extension unit;

s802, receiving the uplink signal of the millimeter wave frequency band through the extension unit, converting the uplink signal of the millimeter wave frequency band into an uplink interface signal, and sending the uplink interface signal to the access unit;

and S803, receiving the uplink interface signal through the access unit, converting the uplink interface signal into a target uplink signal, and sending the target uplink signal to a signal source.

Optionally, the S801 may include: receiving a plurality of paths of uplink radio frequency signals sent by user equipment; generating a local oscillation signal; mixing the multiple uplink radio frequency signals according to the multiple local oscillator signals to obtain multiple uplink preset intermediate frequency signals, and combining the multiple uplink preset intermediate frequency signals into uplink intermediate frequency signals; the multi-path uplink preset intermediate frequency signals respectively correspond to a plurality of preset frequencies, and the multi-path local oscillator signals correspond to the preset frequencies one to one; performing frequency mixing processing on the uplink intermediate frequency signal according to the local oscillation signal to obtain an uplink signal of a millimeter wave frequency band; and sending the uplink signal of the millimeter wave frequency band to the extension unit.

Optionally, when the access unit is connected to the extension unit through an optical fiber or a network cable, the S802 may include: receiving an uplink signal of a millimeter wave frequency band sent by the remote unit; generating a local oscillation signal; dividing the uplink signal of the millimeter wave frequency band into multiple paths of uplink signals of the millimeter wave frequency band, and performing frequency mixing processing on the multiple paths of uplink signals of the millimeter wave frequency band according to multiple paths of local oscillator signals to obtain multiple paths of intermediate frequency analog signals; performing analog-to-digital conversion on the multiple paths of intermediate frequency analog signals to obtain multiple paths of uplink digital signals; and framing the plurality of paths of uplink digital signals to obtain uplink framing signals, and sending the uplink framing signals to the access unit.

Fig. 9 is a schematic diagram of the communication method of the present embodiment, which is illustrated by a complete uplink and downlink process, including:

901, the user equipment sends an uplink radio frequency signal to a communication system;

902, the communication system receives an uplink radio frequency signal sent by the user equipment through the remote unit, converts the uplink radio frequency signal into an uplink signal in a millimeter wave frequency band, and sends the uplink signal in the millimeter wave frequency band to the extension unit;

903, the communication system receives the uplink signal of the millimeter wave frequency band through the extension unit, converts the uplink signal of the millimeter wave frequency band into an uplink interface signal, and sends the uplink interface signal to the access unit;

904, the communication system receives the uplink interface signal through the access unit and converts the uplink interface signal into a target uplink signal;

905, the communication system sends the target uplink signal to the signal source through the access unit;

906, the signal source processes the target uplink signal to obtain an uplink baseband signal and sends the uplink baseband signal to the gateway;

907, the signal source receives a downlink baseband signal sent by the gateway;

908, the signal source sends the downlink baseband signal to the communication system;

909, the communication system receives the downlink baseband signal sent by the signal source through the access unit, converts the downlink baseband signal into a downlink interface signal, and sends the downlink interface signal to at least one extension unit;

910, the communication system receives the downlink interface signal through the extension unit, converts the downlink interface signal into a downlink signal in a millimeter wave band, and sends the downlink signal in the millimeter wave band to at least one remote unit;

911, the communication system receives the downlink signal of the millimeter wave frequency band through the remote unit, and converts the downlink signal of the millimeter wave frequency band into a target downlink radio frequency signal.

912, the communication system sends the target downlink rf signal to the ue through the remote unit.

It should be understood that although the various steps in the flowcharts of fig. 5,7-9 are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Moreover, at least some of the steps in fig. 5,7-9 may include multiple sub-steps or multiple stages that are not necessarily performed at the same time, but may be performed at different times, and the order of performance of the sub-steps or stages is not necessarily sequential, but may be performed in turn or alternating with other steps or at least some of the sub-steps or stages of other steps.

For the specific limitations of the communication method, reference may be made to the limitations of the communication system above, which are not described herein again.

The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A communication system, comprising:

2. The communication system of claim 1, wherein when the access unit is connected to the extension unit fiber or cable, the extension unit comprises:

3. The communication system according to claim 1 or 2, wherein the remote unit comprises:

4. The communication system of claim 1, wherein the access unit is further configured to add a first synchronization signal to the downlink interface signal; the first synchronization signal is used for synchronization between the access unit and the extension unit; the extension unit is further configured to analyze the first synchronization signal from the downlink interface signal, and generate a clock signal and a local oscillator signal of the extension unit according to the first synchronization signal.

5. The communication system according to claim 4, wherein the extension unit is further configured to generate a second synchronization signal, convert the second synchronization signal into a continuous wave signal, and send the continuous wave signal to the remote unit; the second synchronization signal is used for synchronization between the extension unit and the remote unit; the remote unit is further configured to extract the second synchronization signal from the continuous wave signal, and generate a clock signal and a local oscillator signal of the remote unit according to the second synchronization signal.

6. The communication system of claim 5, wherein the second synchronization signal is a specific frequency signal or a Global Positioning System (GPS) signal.

7. The communication system according to claim 1, characterized in that the access unit is radio frequency connected to an active antenna unit, AAU, and/or the access unit is connected to a central/distribution unit, CU/DU, optical fiber or network cable.

8. A communication system, comprising:

9. A method of communication, the method comprising:

10. The method of claim 9, further comprising:

11. The method of claim 10, further comprising:

12. A method of communication, the method comprising: