KR101035690B1 - Antenna embedded remote radio head using a digital hub - Google Patents

Abstract

PURPOSE: An antenna embedded remote radio head using a digital hub is provided to efficiently control an antenna beam. CONSTITUTION: A digital process board(140) changes the phase and the amplitude of a signal. The digital process board distributes the transformed signal into a plurality of digital/RF conversion modules. The digital process board collects each digital signal from a plurality of digital/RF conversion modules using a digital hub. The digital processing board selects a signal with little errors. The digital process board performs demapping and deframing the selected signal. The digital process board distributes the deframed result signal and transmits the result signal to an optical transceiver.

Description

Antenna embedded remote radio head using a digital hub

The present invention relates to an antenna-integrated remote radio head (hereinafter abbreviated as "RRH") using a digital hub, and more particularly, to output the output power of the digital predistortion Doherty power amplifier used in the conventional RRH. The present invention relates to an antenna-integrated RRH using a digital hub that actively distributes the number of patterns used in the arrayed antenna and adjusts the phase of a signal injected into each pattern to actively control the beam of the antenna.

Typically, in high power base station and repeater systems, the transmit power amplification system generates transmit power from a few watts to tens of watts, while operating at a low efficiency of 10%, thus not only requiring a high capacity power supply but also cooling the generated heat. The environmental burden is largely caused by the installation of a cooling device to achieve high efficiency of the power amplifier.

In addition, the RRH (Radio Remote Head) structure in which the RF front-end and the transceiver are directly mounted on the antenna stage has been recently introduced and expanded, and the high growth potential of the RRH market can be predicted [FIG. 1A and FIG. 1B]. See also Base Station Concept.

However, improvements in network capacity and speed for data services, such as fourth-generation mobile communications, can be expected through miniaturization of the cell (the economics of smaller wireless cells are increasingly emerging), but RRH is currently optimized It is tailored to the cell and changes in the RRH are inevitable when the cell radius is reduced (reducing the cell radius requires a large number of base stations and the supply of high efficiency / low cost equipment is urgently needed).

Therefore, as the cell radius is reduced, a new RRH equipment combining the antenna and the current RRH is needed.

The present invention was developed to solve the above problems, and solves various problems caused by the reduction of the cell radius, as well as an antenna-integrated RRH using a digital hub capable of actively and efficiently controlling the beam of the antenna. The purpose is to provide a radio head).

An antenna-integrated Remote Radio Head (RRH) using a digital hub according to the present invention for achieving the above object,

A phased array antenna having a plurality of unit antennas, each of the RF signals received for each unit antenna of the phased array antenna converts the digital signal into a digital signal, and when the signal is transmitted, converts the input digital signal into an RF signal and outputs to the corresponding unit antenna Digital / RF conversion module of the digital converter converts optical signals received from a predetermined digital unit into digital signals sequentially and transmits them in parallel. An optical transceiver that is sequentially converted to a signal and transmitted to the digital unit, and each data distributed and transmitted in parallel from the optical transceiver are mapped and framed according to a setting format, and then transferred to the same signal delay using a digital hub. The phase and amplitude of the signal are converted and distributed to the plurality of digital / RF conversion modules. Each digital signal from multiple digital / RF conversion modules is collected using a digital hub and then de-mapping and de-framing the received signal from selecting (or combining) a signal with low error and parallelizing the result to the optical transceiver. Characterized in that it comprises a digital processing board for distributed transmission to.

Preferably, the digital processing board,

During signal transmission (Tx), each data distributed in parallel from the optical transceiver is mapped to the IQ drawing by the number of data (or the number of bits) according to the setting format, and the resulting signal is separated and extracted, and the signal reception ( In the case of Rx), a data processor for analyzing a data stream generated by demapping the demodulated received signal according to a setting format according to an IQ drawing according to a setting protocol through a deframer, and delivering the result to the optical transceiver; During signal transmission (Tx), the signal is transmitted with the same signal delay, and the phase and amplitude of the extracted signal (or modulated signal) of the data processor are converted and distributed to the plurality of digital / RF conversion modules, and the signal received ( Rx) collects each digital signal converted by the plurality of digital / RF conversion modules, selects (or combines) a signal with less error, and then receives the received signal. It characterized in that demodulates comprising an digital hub delivered to the data processor.

The antenna-integrated remote radio head (RRH) according to the present invention is based on intelligent antenna technology, and the number of patterns used in the phased array antenna is used to output the output power of the digital predistortion Doherty power amplifier used in the conventional RRH. By actively distributing and controlling the phase of the signal injected into each pattern, the beam of the antenna is actively controlled. The effects are as follows.

○ It solves various problems that occur as the cell radius is reduced and can actively control the beam of the antenna.

○ This antenna-integrated RRH is implemented based on SDR, which is the basis of technology that can be applied to other mobile communication systems.

○ With this antenna integrated RRH, it is possible to establish a differentiation strategy of technology and to miniaturize by implementing optical signal / digital signal to RF signal in one module.

○ This antenna integrated RRH can be applied to repeaters as well as base stations.

○ The application of this antenna-integrated RRH to tens of thousands of base stations / relays reduces unnecessary energy consumption, making it possible to realize a low-carbon green concept in IT systems.

○ Securing intelligent antenna technology, RF front end antenna technology of next generation wireless communication base station system, means securing intelligent antenna technology of multi-mode reconfiguration required at RF front end of next generation wireless communication system. There is a technical expectation that enables the realization of next generation multimode system based on.

○ It can be directly applied to next generation multi-mode base station and repeater mobile service and can be applied to antenna of next-generation Wibro and mobile WiMAX base station system.

○ There is a technical ripple effect that enables the implementation of various services of MIMO / SDR technology introduced in next generation wireless communication by applying to next generation MIMO / SDR based multimode base station system.

○ It is possible to apply core element technology to various wireless communication and radio equipment antennas, and it can contribute to the development of next-generation mobile communication integrated base station / repeater technology, next-generation telematics / RFID integration technology, and cognitive radio technology.

○ Securing the next-generation antenna core technology, which is the core technology of future wireless communication services and systems, enables the future-oriented multimedia service implementation in wireless communication and can be expected to succeed in driving the growth of new wireless communication industry.

1A is a diagram illustrating a general standard base station, and FIG. 1B is a conceptual diagram of an RRH base station.
2 illustrates a typical cell environment.
Figure 3 is a block diagram showing an antenna-integrated Remote Radio Head (RRH) using a digital hub according to the present invention
Figure 4 is a detailed block diagram showing an example of a digital processing board according to the present invention
5 is a system conceptual diagram of an antenna-integrated RRH using a digital hub according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described the present invention.

However, the embodiments described below are merely to describe in detail enough to be able to easily carry out the invention by those skilled in the art to which the present invention pertains, thereby limiting the protection scope of the present invention It does not mean.

In order to clearly describe the present invention, parts irrelevant to the description are omitted and like reference numerals denote like parts throughout the specification.

Throughout the specification and claims, when a part includes a certain component, it means that it may include other components, not to exclude other components unless specifically stated otherwise.

3 is a block diagram showing an antenna-integrated Remote Radio Head (RRH) using a digital hub according to the present invention.

As shown in FIG. 3, the antenna-integrated RRH 100 includes a phased array antenna 110, a digital / RF conversion module 120, an optical transceiver 130, and a digital processing board. It is a structure of 140.

That is, the RF signal received for each of the phased array antenna 110 and the phased array antenna 110 having a plurality of unit antennas is converted into a digital signal, and when the signal is transmitted, the input digital signal is converted into an RF signal. A plurality of digital / RF conversion module 120 outputs to the unit antenna, the optical signal received from the predetermined digital unit 150 at the time of signal transmission sequentially converts the optical signal into a digital signal, distributed in parallel, and receives the signal (Rx) In this case, the optical transceiver 130 sequentially converts the data transmitted in parallel into serial streams and optical signals and transmits the data to the digital unit 150, and sets each data distributed in parallel from the optical transceiver 130. After mapping and framing according to the format (or protocol), the digital hub is used to deliver the same signal delay, and the signal's phase and amplitude are converted to The digital / RF conversion module 120, collects each digital signal from the plurality of digital / RF conversion modules 120 using a digital hub, and then selects (or combines) a signal having less error. It is a structure of a digital processing board 140 for demapping and de-framing a signal, and transmitting the result of the signal to the optical transceiver 130 in parallel.

Here, the phased array antenna 110 is formed of a unit antenna (cross display on the drawing) arranged to enable phase adjustment and transmits / receives an RF signal. Specifically, the RF signals output from the plurality of digital / RF conversion modules 120 are input to the corresponding unit antenna through an RF interface (for example, an RF dedicated cable) and transmitted, or the RF signals received from the outside are unit antennas. For each input to the plurality of digital / RF conversion module 120 through the RF interface. For reference, the phased array antenna 110 is designed to solve the problem that the reception sensitivity deteriorates according to the positions of the existing fixed beams, which are directional according to the mutual positions of the antennas. It is to change the radiation direction of the beam.

The digital / RF conversion module 120 is connected in series to a specific unit antenna of the phased array antenna 110 through an RF interface (eg, a dedicated cable for RF), and provides a low voltage differential signal (LVDS) interface. It is connected to the digital processing board (Board) 140 through. In this way, the digital signal input from the digital processing board 140 is converted into an RF signal and output to the corresponding unit antenna of the phased array antenna 110, and the RF signal input through the unit antenna of the phased array antenna 110 The signal is converted into a digital signal and input to the digital processing board 140. The LVDS interface may use any one of an interface for high speed data communication as a low voltage differential signal.

The optical transceiver 130 is installed between the digital unit 150 and the digital processing board 140. When the signal is transmitted for high speed communication, the optical transceiver 130 converts the optical signal received from the digital unit 150 and converts it. The optical signal is converted into a digital signal and distributed to the digital processing board 140 in parallel. When the signal is received, data distributed in parallel from the digital processing board 140 is converted into a serial stream, and the converted serial stream is converted into an optical signal and transmitted to the connected digital unit 150.

The digital processing board 140 is installed between the optical transceiver 130 and the digital / RF conversion module 120. When the signal is transmitted, data distributed in parallel from the optical transceiver 130 are mapped according to a setting format. After framing, the signal is transmitted to the same signal delay using the built-in digital hub, and the signal is converted to the plurality of digital / RF conversion modules 120 by converting the phase and amplitude of the signal. Each digital signal from the / RF conversion module 120 is collected using a digital hub, and then de-mapping and de-framing of a received signal obtained by selecting (or combining) a signal having a low error and outputting the result of the optical transceiver 130. Is distributed in parallel.

Hereinafter, the digital processing board according to the present invention of FIG. 3 will be described in more detail with reference to FIG. 4.

4 is a block diagram illustrating a digital processing board according to the present invention as an example.

As shown in FIG. 4, the digital processing board is largely composed of a data processor 141 and a digital hub 142.

Here, the data processing unit 141 is installed between the optical transceiver 130 and the digital hub 142, the data transmitted in parallel from the optical transceiver 130 in the signal transmission (Tx) in accordance with the setting format data As many as the number (or the number of bits) are mapped to the IQ drawing, the signals resulting from the mapping are extracted and input to the digital hub 142.

When the digital hub 142 demodulates the received signal at the time of signal reception (Rx), that is, each digital signal (a signal obtained by converting RF signals received by the unit antennas of the phased array antenna from the outside into digital). When the received signal is demodulated by selecting (or combining) a signal having few errors, the demodulated signal is de-mapped based on the IQ drawing according to the setting format to generate a data stream, and the generated data stream is deframed. Through the signal analysis (eg, data interval designation, start point or end point designation, etc.) according to the set protocol to pass the result to the optical transceiver 130.

The digital hub 142 is connected to the data processing unit 141, the output terminal is connected to the digital / RF conversion module 120, the signal receiving input terminal is a digital / RF conversion module 120, and the output terminal is data. Connected to the processor 141, the signal is transmitted at the same signal delay (Tx), and the phase and amplitude of the extracted signal (ie, the modulated signal) of the data processor 141 are converted to the main beam of the antenna. Control (e.g., vertical angle adjustment, etc.), and at the time of signal reception (Rx), each digital signal (a signal obtained by converting RF signals received from external units to digital by phase antennas) is collected. After demodulating the received signal by selecting (or combining) a small number of signals, the demodulated signal is input to the data processor 141.

Hereinafter, the operation of the antenna integrated RRH using the digital hub according to the present invention of FIG. 3 using the digital processing board of FIG. 4 will be described.

The operation description will be described by dividing the transmission (Tx) operation and the reception (Rx) operation (refer to FIGS. 1 and 2 together).

① Tx operation

First, the optical transceiver 130 converts an optical signal received from the digital unit 150 into a digital signal and transmits it in parallel.

Next, the data processing unit 141 maps the distributed data in parallel to the IQ drawing by the number of data (or the number of bits) according to the setting format.

The signals resulting from the mapping are separated and extracted.

Next, the digital hub 142 converts the phase and amplitude of the extracted signal (ie, the modulated signal) to be delivered at the same cable transmission time (or at the same signal delay).

As a result, the main beam of the antenna can be controlled (eg, vertical angle adjustment, etc.).

Meanwhile, when the conversion of the phase, amplitude, and the like is completed, the digital hub 142 distributes the converted signal to the plurality of digital / RF conversion modules 120.

The digital / RF conversion module 120 converts the distributed digital signal into an RF signal.

Finally, the converted RF signal is transmitted through the unit antenna of the phased array antenna 110 connected to the digital / RF conversion module 120.

② Receive (Rx) operation

First, RF signals are received for each unit antenna through the unit antenna of the phased array antenna 110.

Then, each digital / RF conversion module 120 connected to the corresponding unit antenna converts each received RF signal into a digital signal.

Next, the digital hub 142 demodulates the received signal by collecting each converted digital signal and then selecting (or combining) a signal having less error.

Then, the data processing unit 141 demaps the demodulated signal according to the IQ drawing according to the setting format to generate a predetermined data stream.

Then, the generated data stream is analyzed through a deframer according to a set protocol (eg, data section designation, start point or end point designation, etc.).

Then, the data from the signal analysis is distributed and transmitted to the optical transceiver 130 in parallel.

Then, the optical transceiver 130 converts the data transmitted in parallel to the serial stream, converts the converted serial stream into an optical signal and transfers the data to the connected digital unit 150 to complete the reception (Rx) operation.

Finally, with reference to the accompanying Figure 3 will be described the system and the theoretical concept underlying the antenna-integrated RRH according to the present invention of FIG.

5 is a system conceptual diagram of an antenna integrated remote radio head (RRH) using a digital hub according to the present invention.

As shown in FIG. 5, a system of an antenna-integrated remote radio head (RRH) using the digital hub is based on intelligent antenna technology, and phases the output power of a digital predistortion Doherty power amplifier used in conventional RRHs. The number of patterns used in the arrayed antenna is distributed and the phase of the signal injected into each pattern is adjusted to actively control the beam of the antenna.

[Reference 1]

For reference, a comparison between the features of the antenna-integrated RRH and the conventional antenna-separated RRH according to the present invention is shown in Table 1 below.

Item Antenna integrated RRH Antenna detachable RRH
(Including antennas) Remarks price Cheap expensive weight light heavy size small Relatively small efficiency high Relatively high HPA Removal

EIRP

Relatively high

high -. Since cell radius is small, it doesn't have to be as high
-. Beam pattern adjustment overcomes relatively low EIRP Dual band service Low cost High cost System Flexibility high low

[Reference 2]

For reference, the development method of the antenna integrated remote radio head (RRH) according to the present invention is shown in Table 2.

Field Contents and Method Obstacles Solutions Optic interface
design
Multi-cascade optic transceiver implementation
-Dual band transceiver implementation Delay calibration required for cascade Solved by using a dedicated chip Digital Processing
-Digital beam control algorithm development
-Development of upper communication algorithm
-Development of lower module control algorithm
-DRF module control algorithm development Algorithm collisions fail to provide an optimized environment Provide optimized environment by operating system implementation similar to OS concept Digital Interface Design
-LVDS implementation for high speed communication
-High speed data communication using FPGA Gate takes a lot Minimize the number of gates used as an optimization design Digital Hub Design
Digital signal distribution design and implementation
Leveraging FPGAs to Deliver Digital Hub Functionality Difficult implementation of the initial idea stage Apply basic concepts of Internet equipment DRF module design
-Digital (input) / RF (output) design technology
-Packaging technology
Difficult implementation of the initial idea stage
Need to Implement Accurate LO Frequency
Optimal structure suggestion through simulation
Proposal of miniaturization differentiation by applying packaging technology
LO frequency Cal. Feature implementation Phased array
Antenna design technology
-Optimal antenna element development
-Optimal array structure Insufficient antenna structure analysis data for optimal beam control Present antenna structure for optimal beam control
Presenting Differentiation Structure Enclosure design and
Thermal analysis
-Optimized heat dissipation design
-Thermal analysis ground mechanism design Lack of analysis of system presence inside the antenna Differentiated heat dissipation structure

Explanation of symbols on the main parts of the drawings
110: phased array antenna 120: digital / RF conversion module
130: optical transceiver 140: digital processing board
150: digital unit 141: data processing unit
142: digital hub

Claims (2)

A phased array antenna having a plurality of unit antennas;
A plurality of digital / RF conversion module for converting the RF signal received for each unit antenna of the phased array antenna into a digital signal, and converts the input digital signal into an RF signal when outputting the signal to the corresponding unit antenna;
When transmitting a signal, an optical signal received from a predetermined digital unit is sequentially converted into a digital signal and distributed in parallel. When receiving a signal (Rx), the distributed data is transmitted in parallel into a serial stream and an optical signal. An optical transceiver for transmitting to the unit; And
After mapping and framing each data transmitted in parallel from the optical transceiver according to a setting format, the data is transmitted with the same signal delay using a digital hub, and the signal phase and amplitude are converted to convert the plurality of digital / RF signals. Module, and each digital signal from the plurality of digital / RF conversion modules is collected using a digital hub and demapping and deframing the received signal resulting from selecting (or combining) a signal with low error. An antenna-integrated RRH using a digital hub comprising a digital processing board for transmitting transmission in parallel to the optical transceiver. The method of claim 1,
The digital processing board
During signal transmission (Tx), each data distributed in parallel from the optical transceiver is mapped to the IQ drawing by the number of data (or the number of bits) according to the setting format, and the resulting signal is separated and extracted, and the signal reception ( Rx), a data processing unit for analyzing a data stream generated by demapping the demodulated received signal according to a setting format according to an IQ drawing according to a setting protocol through a deframer, and transferring the result to the optical transceiver; And
During signal transmission (Tx), the signal is transmitted with the same signal delay, and the phase and amplitude of the extracted signal (or modulated signal) of the data processor are converted and distributed to the plurality of digital / RF conversion modules, and the signal received ( Rx) includes a digital hub that collects each digital signal converted by the plurality of digital / RF conversion modules, selects (or combines) a signal with less error, demodulates a received signal, and delivers the received signal to the data processor. Antenna-integrated RRH using a digital hub, characterized in that made.

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