CN104135294A - E-waveband wireless transmission signal generating equipment - Google Patents

Abstract

The invention relates to E-waveband wireless transmission signal generating equipment. An Ethernet frame is converted into a media access frame through a high-speed Ethernet interface, and is connected to a digital baseband processing module; the digital baseband processing module is used for finishing data coding, mapping the coded data into a digital character, encapsulating the data into an E-waveband frame structure and finishing shaping filtering and rate conversion through a transmission filtering module, and is connected to a digital medium-frequency module; and the digital medium-frequency module is used for converting a digital baseband signal into a digital medium-frequency signal, inputting the digital medium-frequency signal into a DAC (Digital-to-Analog Converter) and a radio frequency front end, generating an E-waveband wireless transmission signal, and transmitting the E-waveband wireless transmission signal through an E-waveband antenna. The E-waveband wireless transmission signal generating equipment is compatible with a plurality of modulation ways, and meets the requirement of high-rate transmission.

Description

An E-band wireless transmission signal generating device

technical field

The invention relates to the technical field of E-band high-speed wireless transmission, in particular to an E-band wireless transmission signal generation device.

Background technique

Microwave is a common wireless communication technology. It has the characteristics of long transmission distance, large capacity, quick deployment, and strong damage resistance. It is widely used in the relay and backhaul of communication systems. With the popularity of smart mobile terminals and the vigorous development of mobile Internet in recent years, wireless data services have shown explosive growth. The conventional spectrum resources from 6GHz to 38GHz have been exhausted, and microwave communication will expand to higher frequency bands. The E-band microwave frequency band will be the main solution for cellular wireless backhaul in the future.

The E-band is the microwave frequency spectrum resource with the largest channel spacing released so far by the International Telecommunications Union Radio Organization (ITU-R). Composed of 71GHz-76GHz and 81GHz-86GHz spectrum resources, it can carry high-speed wireless transmission services above Gbit. The European Electronic Communications Commission (ECC)'s suggestion for the E-band frequency band is: the minimum channel spacing is 250MHz, the entire 5GHz available modulation frequency band is divided into 19 sub-frequency bands, and 1 to 4 sub-frequency band combinations can be used when transmitting services, and the channel spacing can be adjusted The maximum is 1GHz, and when high-order modulation is used, E-band microwave can realize high-capacity transmission of 1 to 5Gbps.

In recent years, with the rapid deployment and development of LTE, cellular wireless backhaul networks are facing more and more serious frequency offset deficit problems. With the introduction and research of 5G communication requirements, the problem of spectrum scarcity in backhaul networks will become more severe. The application of E-band microwave makes it possible to carry future wireless communication service requirements. At present, many countries have opened the restrictions on the use of E-band frequency bands, and scientific research institutions and organizations in various countries are actively carrying out experiments and research and development of E-band high-speed wireless transmission equipment for next-generation wireless backhaul networks. At present, the problems faced by the baseband processing part of E-band transmission equipment mainly lie in the fact that the digital baseband processing rate including encoding, modulation, shaping filter and digital up-conversion, and the characteristics of the front-end analog devices of the radiation deviation cannot meet the requirements of the E-band transmission system above 10Gbps.

In the field of high-speed wireless transmission, there is a serious spectrum deficit problem. As a common wireless communication technology, it has the characteristics of long transmission distance, large capacity, fast deployment, and strong damage resistance, and is widely used in the field of high-speed wireless transmission. However, the conventional microwave spectrum from 6GHz to 38GHz has been exhausted and needs to be extended to higher frequency bands. The IEEE802.11ad standard stipulates that it works in the 60GHz frequency band, and can realize communication at a maximum rate of 7Gbps. This standard is already the highest rate supported by existing standards, but it still has a huge gap with the goal of 10-100Gbps "wireless optical fiber". At the same time, there are still shortcomings such as short transmission distance, large interference, and lack of spectrum resources. With the development of LTE/LTE-Advanced, in the future 4G and B4G era, existing standards are far from meeting the needs of wireless backhaul networks. Future wireless communication, especially high-speed wireless transmission, needs to open up new spectrum to meet new requirements.

The E-band is the widest spectrum resource allocated by the ITU so far. It has two 5GHz continuous spectrums, namely 71-76GHz and 81-86GHz, which can well solve the problem of spectrum deficit. Ultra-wide spectrum resources make it possible to achieve extremely high transmission rates in theory. Due to the sufficient guard interval, the E-band transmission system suffers little interference from signals in other frequency bands, and it is easy to realize interference-free transmission. This frequency band also has the characteristics of low environmental fading, which makes the E-band wireless transmission system suitable for medium and long-distance transmission. It is the main solution for future cellular wireless backhaul and can be used as an upgrade and replacement for traditional microwave access.

However, the current E-band wireless transmission system architecture still has no standards to follow. There are a series of speed and efficiency problems in the generation of E-band signals, encoding methods, high-speed filtering, and radio frequency signal generation. They only stay in the experimental research stage and can be realized. Signal generating equipment is still very scarce.

Contents of the invention

The technical problem to be solved by the present invention is to provide an E-band wireless transmission signal generating device, which can realize the conversion from high-speed Ethernet to E-band radio frequency microwave signals, is compatible with various modulation methods, and meets the high-speed transmission requirements.

The technical solution adopted by the present invention to solve the technical problem is to provide an E-band wireless transmission signal generating device, including a high-speed Ethernet interface, a digital baseband processing module, a digital intermediate frequency module, a global clock control module, and a multi-channel analog intermediate frequency combining module , a radio frequency front-end module and a duplexer; the high-speed Ethernet interface is used to convert the Ethernet frame of the high-speed Ethernet into a parallel media access frame, and output to the digital baseband processing module; the digital baseband processing module includes : The digital encoding module is used to complete multi-channel encoding to obtain parallel multi-channel encoded signals; the modulation mapping module modulates the encoded signals, and the modulated data is represented by multiple bits, and the real part and the imaginary part are represented by the same mapping relationship; The framing module is used to add and insert the header sequence and pilot sequence to the modulated data; the transmission filter module is used to complete the shaping filter and rate conversion, and insert the preamble sequence to obtain parallel digital baseband signals and output to the digital intermediate frequency module; the digital intermediate frequency module is used to convert parallel digital baseband signals into digital intermediate frequency signals; the multi-channel analog intermediate frequency combining module is used to combine multi-channel analog intermediate frequency signals into a unified analog intermediate frequency signal; The radio frequency front-end module up-converts the digital intermediate frequency signal into an E-band microwave signal, and sends it to the duplexer for transmission by the duplexer; the global clock control module is used to control all E-band wireless transmission signal generation equipment Module synchronization.

The high-speed Ethernet interface converts the Ethernet frame of the high-speed Ethernet into a parallel PHY frame, and then converts it into a parallel MAC frame.

The digital encoding module uses BCH, RS or LDPC encoding to complete dual-channel or multi-channel encoding.

The modulation mapping module is compatible with BPSK/QPSK/MQAM modulation modes.

The sending filtering module implements shaping filtering and rate conversion by means of table look-up and polyphase filtering, wherein the data look-up table part adopts the table look-up method, and the leading part adopts the pre-storage method.

The state machine representation of the framing module when the data stream is output is divided into a stop state, a header sequence state and a data state. Beneficial effect

Owing to adopting above-mentioned technical scheme, the present invention has following advantage and positive effect compared with prior art: the present invention converts Ethernet frame into media access frame by high-speed Ethernet interface, and is connected to digital baseband processing module; The data encoding is completed by the digital baseband processing module, and the encoded data is mapped into digital symbols, and the data is encapsulated into an E-band frame structure, and then the shaping filter and rate conversion are completed by the sending filter module, and connected to the digital intermediate frequency module; the digital intermediate frequency module The digital baseband signal is converted into a digital intermediate frequency signal, and input to the DAC and RF front end to generate an E-band wireless transmission signal, which is transmitted by the E-band antenna. It is not only compatible with various modulation methods, but also meets the high-speed transmission requirements.

Description of drawings

Fig. 1 is a general block diagram of the present invention;

Fig. 2 is a block diagram of a digital baseband processing module and a digital intermediate frequency module in the present invention;

Fig. 3 is a schematic diagram of the global clock control module in the present invention;

Fig. 4 is the realization block diagram of encoder module among the present invention;

Fig. 5 is a block diagram of the implementation of the framing module in the present invention;

Fig. 6 is a structural diagram of the state machine of the framing module in the present invention;

Fig. 7 is a block diagram of the implementation of the sending filter module in the present invention;

Fig. 8 is a block diagram of realizing the digital intermediate frequency module in the present invention.

Detailed ways

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

The embodiment of the present invention relates to an E-band wireless transmission signal generating device, as shown in Figure 1 and Figure 2, including a high-speed Ethernet interface, a digital baseband processing module, a digital intermediate frequency module, a global clock control module, and a multi-channel analog intermediate frequency combination Module, radio frequency front-end module and duplexer; The high-speed Ethernet interface is used to convert the Ethernet frame of the high-speed Ethernet into a parallel media access frame, and output to the digital baseband processing module; the digital baseband processing module Including: digital coding module, used to complete multi-channel coding to obtain parallel multi-channel coded signals; modulation mapping module, to modulate coded signals, the modulated data is represented by multiple bits, and the real part and imaginary part are represented by the same mapping relationship ; The framing module is used to complete the addition and insertion of the header sequence and the pilot sequence to the modulated data; the transmission filter module is used to complete the shaping filter and rate conversion, and insert the preamble sequence to obtain parallel digital baseband signals, and Output to the digital intermediate frequency module; the digital intermediate frequency module is used to convert the parallel digital baseband signal into a digital intermediate frequency signal; the multi-channel analog intermediate frequency combining module is used to merge the multi-channel analog intermediate frequency signal into a unified analog intermediate frequency signal; The radio frequency front-end module up-converts the digital intermediate frequency signal into an E-band microwave signal, and sends it to the duplexer, which is emitted by the duplexer. The duplexer can switch between two 5GHz bandwidths of the E-band to distinguish between sending and receiving signals; The global clock control module is used to control the synchronization of all modules in the E-band wireless transmission signal generating equipment.

As shown in FIG. 3 , the definitions of the input ports of the global clock control module in this embodiment are: the frequency of the input clock 16 is 312.5 MHz; the reset signal terminal 17 ; and the input enable signal terminal 18 . The definitions of the output ports are: frame start signal terminal 19, once per frame; header sequence start signal terminal 20, once per frame; intra-frame signal counter 21, incremented once per clock.

As shown in FIG. 4 , the coding module in this embodiment uses BCH, RS, LDPC and other coding methods to complete dual-channel or multi-channel coding, and the working clock is 166.67 MHz. When encoding, first read data in FIFO22, the period of the enable signal bch_fifo_rd (23) for reading data refers to the definition of frame_mod, and the obtained data is sent to 6 parallel encoders to complete dual-channel encoding, and finally The encoded data is written into the FIFO of the next stage.

As shown in Table 1 and Table 2, this embodiment is compatible with multiple modulation modes such as BPSK/QPSK/MQAM, where M may be 16, 32, 64, ..., and supports various high-profile modes. In this embodiment, 16QAM is taken as an example. In order to unify BPSK, QPSK and 16QAM, the modulated data is represented by 6 bits, and the real part and the imaginary part adopt the same mapping relationship, each represented by 3 bits.

Table 116QAM and BPSK mapping table

Table 2 QPSK mapping table

As shown in FIG. 5 , in this embodiment, the framing module completes the addition of the header sequence (Header) and the pilot sequence (Pilot), and transmits all data to the sending filter module in the form of 6 parallel data streams. This module is mainly composed of two parts: bit width conversion 25 and framing 26 .

As shown in FIG. 6 , in this embodiment, the data flow output of the framing module can be represented by this state machine: it is divided into three states: stop 27 , header sequence 28 and data 29 . It is in the stop state at the beginning. When the rising edge of header_start arrives, the state machine enters the header sequence state and starts to transmit header data. At the same time, the header_counter starts counting from 0. The length of the entire header is 48 symbols. Because 6 channels are parallel, a total of 8 are required. Clock cycle, when header_counter=7, the state machine jumps to the data state, starts to transmit the modulated IQ data, and data_counter starts counting from 0 at the same time, when the data_counter counts to 863, a frame of data transmission is completed, and the state machine enters the stop state, Wait for the next arrival of header_start.

As shown in FIG. 7 , the transmission filtering module in this embodiment is realized by zero multiplication based on a look-up table method, aiming at completing shaping filtering and rate conversion from 6 channels to 16 channels, and adding a preamble (Preamble). Input Frame_data_real (30) and Frame_data_imag (31) are respectively I, two road data frames of Q, and Frame_mod (31) is the mode of input frame, and Frame_start (32) is a data frame start sign. The output is I, Q two-way signals filter_real_out (33) and filter_imag_out (34) after the preamble sequence is inserted and shaped and filtered. The module input clock clk (35) is 312.5MHz, the data look-up table 36 part adopts the look-up method, the leading part 37 adopts the pre-storage method, and finally the output control module 38 controls the output timing.

As shown in FIG. 8 , the connection relationship between the digital intermediate frequency module, the digital up-conversion module 39 and the parallel-to-serial conversion module 40 in this embodiment is as shown in the figure. The frequency of the input clock clk_312.5 of the digital up-conversion module is 312.5MHz, and the input is I and Q two-way complex signals, which are respectively filter_real_out (42) and filter_imag_out (43), divided into 16 parallel inputs. In this embodiment, the output of the digital up-conversion module is 16 channels of parallel digital real signals, and the carrier frequency is 1.25 GHz. In this embodiment, the frequency of the input clock clk_625 ( 44 ) of the parallel-to-serial conversion module is 625 MHz, and the output is 4 differential outputs ( 45 ), each of which is 12 bits, and is output to a high-speed DAC.

In this embodiment, the output of the high-speed DAC is a dual-channel analog intermediate frequency signal. Through the multi-channel analog intermediate frequency combining module, the two-channel signals are combined to form an analog intermediate frequency signal. After passing through the radio frequency front-end module, an E-band radio frequency signal is generated. Finally, a transmissible E-band wireless transmission signal is generated through a duplexer and an E-band antenna.

Claims (6)

1. A kind of E band wireless transmission signal generation equipment is characterized in that, comprises high-speed ethernet interface, digital baseband processing module, digital intermediate frequency module, global clock control module, multi-channel analog intermediate frequency combining module, radio frequency front-end module and duplexer ; The high-speed Ethernet interface is used to convert the Ethernet frame of the high-speed Ethernet into a parallel media access frame, and output to the digital baseband processing module; the digital baseband processing module includes: a digital encoding module for completing Multi-channel encoding to obtain parallel multi-channel encoded signals; the modulation mapping module is used to modulate the encoded signal, and the modulated data is represented by multiple bits, and the real part and imaginary part are represented by the same mapping relationship; the framing module is used for modulation After the data completes the addition and insertion of the header sequence and the pilot sequence; the transmission filter module is used to complete the shaping filter and rate conversion, and insert the preamble sequence to obtain a parallel digital baseband signal and output it to the digital intermediate frequency module; The digital intermediate frequency module is used to convert the parallel digital baseband signal into a digital intermediate frequency signal; the multi-channel analog intermediate frequency combining module is used to combine the multi-channel analog intermediate frequency signal into a unified analog intermediate frequency signal; the radio frequency front-end module converts the digital intermediate frequency signal The frequency is up-converted into an E-band microwave signal, and sent to the duplexer for transmission; the global clock control module is used to control the synchronization of all modules in the E-band wireless transmission signal generating device. 2. The E-band wireless transmission signal generating device according to claim 1, wherein the high-speed Ethernet interface converts the Ethernet frame of the high-speed Ethernet into a parallel PHY frame, and then is converted into a parallel MAC frame. 3. The E-band wireless transmission signal generating device according to claim 1, characterized in that, said digital encoding module adopts BCH, RS or LDPC encoding to complete dual-channel or multi-channel encoding. 4. The E-band wireless transmission signal generating device according to claim 1, wherein the modulation mapping module is compatible with BPSK/QPSK/MQAM modulation modes. 5. E-band wireless transmission signal generation equipment according to claim 1, is characterized in that, described transmission filtering module realizes forming filtering and rate conversion with look-up table method and polyphase filter mode, wherein, data look-up table part adopts look-up table The table method, the leading part adopts the pre-storage method. 6. The E-band wireless transmission signal generating device according to claim 1, characterized in that, the state machine representation of the framing module when the data stream is output: is divided into a stop state, a header sequence state and a data state.