Sub-band full-duplex communication system, method and base station

Abstract

The embodiment of the invention provides a sub-band full-duplex communication system and method and a base station, the sub-band full-duplex communication system comprises a first branch and a second branch, the first branch comprises a sending link and a reference link, and the sending link comprises a DPD, a DAC, a mixer, a power amplifier PA, a circulator, a filter and a first antenna array which are connected in sequence; the second branch comprises a receiving link, and the receiving link comprises a second antenna array, a low-noise amplifier, a frequency mixer and an ADC which are connected in sequence; in the SBFD time slot, the first branch sending link is used for performing downlink radio frequency transmission on a baseband signal, and the reference link collects a radio frequency signal output by the PA as a reference signal; and the second branch receiving link is used for performing uplink radio frequency transmission on the wireless signal. And carrying out linear cancellation processing on the receiving signal output by the receiving link according to the reference signal. Interference between uplink and downlink signals is reduced through combination of separated arrangement of the transmitting and receiving antenna arrays and linear cancellation processing.

Description

Sub-band full-duplex communication system, method and base station Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a sub-band full-duplex communication system, method and base station. Background Art

[0002] 5G networks have entered large-scale commercial use, with high-bandwidth time-division duplex (TDD) primarily utilizing spectrum frequencies greater than 3 GHz. Existing 5G TDD-based networks suffer from significant uplink coverage shortcomings. For example, if network coverage requirements are met, with downlink speeds of 100 Mbps and uplink speeds of 5 Mbps, the downlink coverage satisfaction rate is greater than 80%, while the uplink coverage satisfaction rate is less than 50%, presenting significant uplink coverage challenges.

[0003] The traditional TDD frame structure divides time-frequency resources along the time dimension, with some time allocated for uplink and some for downlink. In existing networks, primarily for enhanced mobile broadband (eMBB) applications, typical downlink-to-uplink time allocation ratios range from 7:3 to 8:2, with the uplink accounting for a relatively small portion. To improve uplink coverage, sub-band full-duplex technology has been introduced. Compared to the TDD frame structure, the sub-band full-duplex frame structure significantly improves uplink coverage. In the traditional TDD frame structure, each time slot exclusively occupies the entire frequency domain for both uplink and downlink. Sub-band full-duplex technology utilizes sub-band frequency division multiplexing (FDM) across the wide bandwidth of the TDD spectrum. This is achieved by separately configuring uplink and downlink transmission resources on different frequencies in some time slots. Since more uplink and downlink time slots are configured, the uplink and downlink delays can be reduced. The ability to flexibly configure more uplink resources helps to enhance uplink coverage and improve capacity. However, since uplink and downlink transmissions are performed in the same time slot, there is a mutual influence between the uplink and downlink, especially the influence of the downlink on the uplink, which can easily lead to congestion of the uplink receiving channel and affect the uplink coverage.

[0004] Summary of the Invention

[0005] In view of the above, embodiments of the present invention provide a sub-band full-duplex communication system, method, and base station, which reduce interference between uplink and downlink signals by combining separate transmit and receive antenna array settings and linear cancellation processing.

[0006] In the first aspect, an embodiment of the present application provides a sub-band full-duplex communication system, comprising: a first branch, including a transmitting link and a reference link, the transmitting link including a digital pre-distortion DPD, a digital-to-analog converter DAC, a mixer, a power amplifier PA, a circulator, a filter and a first antenna array connected in sequence; a second branch, including a receiving link, the receiving link including a second antenna array, a filter, a low-noise amplifier, a mixer and an analog-to-digital converter ADC connected in sequence; in the SBFD time slot, the transmitting link is used to perform downlink RF transmission of the baseband signal; the receiving link is used to perform uplink RF transmission of the wireless signal; the reference link collects the amplified RF signal output by the PA to obtain a reference signal, and performs linear cancellation processing on the digital received signal output by the receiving link based on the reference signal.

[0007] Using the above technical solution, in the SBFD time slot, the transmitting link is used for downlink RF transmission of the baseband signal; the receiving link is used for uplink RF transmission of the wireless signal, and the first antenna array and the second antenna array are set separately to improve the isolation between the transmitting and receiving antenna arrays; and the RF signal output by the PA is collected through the reference link as a reference signal, and the digital received signal output by the receiving link is linearly cancelled based on the reference signal to further reduce the impact of the downlink signal on the uplink signal.

[0008] In some embodiments, the linear cancellation processing performed on the digital received signal according to the reference signal may be performed in the second branch receiving link (before the received signal is sent to the baseband) or in the baseband.

[0009] In a possible implementation of the first aspect above, the reference link includes a coupler, a mixer, and an analog-to-digital converter connected in sequence. The coupler is used to collect the radio frequency signal after the PA. The mixer and the analog-to-digital converter perform down-conversion and sampling in sequence to convert the radio frequency signal into a digital signal, so that the digital signal is used as a reference signal, and linear cancellation processing is performed on the received signal output by the receiving link based on the reference signal.

[0010] Using the above technical solution, the RF signal after the PA is collected through a coupler, and the mixer and analog-to-digital converter perform down-conversion and sampling in sequence. The RF signal is converted into a digital signal, which is used as a reference signal. The digital received signal output by the ADC of the receiving chain is linearly cancelled based on the reference signal.

[0011] In a possible implementation of the first aspect above, the reference link further includes a filter, one end of the filter is connected to the coupler, and the other end of the filter is connected to the mixer.

[0012] Using the above technical solution, if the filter is an adjustable filter, the signal collected by the coupler is filtered by the adjustable filter to reduce the energy within the downlink sub-band range to avoid limiting the dynamic range of the ADC in the reference link. At the same time, the adjustable filter can adjust the passband bandwidth according to actual needs to increase the applicability of the sub-band full-duplex system. Among them, one implementation method of the adjustable filter is to include multiple filters with different bandwidths, and select filters of different bandwidths by switching as needed. Of course, in other embodiments, the filter can also be a fixed bandwidth filter.

[0013] In a possible implementation of the first aspect above, the reference link further includes a switch unit and a low-noise amplifier, one end of the switch unit is connected to the mixer, and one end of the low-noise amplifier is connected to the circulator; when the other end of the switch unit is connected to the filter, the first antenna array is used to send downlink signals; when the other end of the switch unit is connected to the other end of the low-noise amplifier, the first antenna array is used to receive uplink signals.

[0014] In the SBFD time slot, the first branch transmission link works to convert the baseband signal to radio frequency for downlink transmission; at the same time, the switch in the reference link is switched to connect with the filter. At this time, the reference link works in the reference channel mode, which is used to perform real-time sampling of the transmitted radio frequency signal after the PA to obtain a reference signal. The second branch receiving link works normally and receives the wireless signal from the second antenna array port to obtain an uplink signal. Since the transmitted signal leaks to the receiving link, the received uplink signal contains both the service signal and the transmitted self-interference signal. The received signal is linearly cancelled based on the reference signal obtained by sampling the reference channel to eliminate the self-interference component in the uplink signal. The two branches eliminate the impact of the downlink on the uplink by combining antenna isolation and linear cancellation.

[0015] By adopting the above technical solution, the function of the first antenna array can be adjusted according to uplink and downlink requirements. For example, it can be used to send downlink signals or receive uplink signals.

[0016] In a possible implementation of the first aspect above, the receiving link further includes a filter, one end of the filter is connected to the low noise amplifier, and the other end of the filter is connected to the mixer. In the SBFD time slot, the passband bandwidth of the adjustable filter matches the UL sub-band, reducing the DL sub-band energy and avoiding saturation of the receiving link ADC. In the UL time slot, the passband bandwidth of the adjustable filter is switched to the entire frequency band without affecting the uplink full-band receiving signal. Since the downlink signal strongly interferes with the uplink receiving link, the receiving link and the reference link have high requirements for the ADC dynamic range, which poses a great challenge to engineering implementation. By adding a filter, the dynamic range requirements of the receiving link and the reference link are reduced, which facilitates engineering implementation.

[0017] When the filters of the receiving link and the reference link are fixed-bandwidth filters, only fixed sub-band bandwidth configuration is supported.

[0018] When the filters of the receiving link and the reference link are adjustable bandwidth filters, flexible configuration of the UL subband bandwidth can be supported.

[0019] In a possible implementation of the first aspect, the first branch includes multiple transmission links and multiple reference links, and the second branch includes multiple reception links. In the first branch, the first antenna array, the transmission links, and the reference links are in a one-to-one correspondence. In the second branch, the second antenna array and the reception links are in a one-to-one correspondence.

[0020] The multiple receiving RF chains and the multiple transmitting RF chains have a one-to-one correspondence with the target antenna array, and the target antenna array may be the first antenna array or the second antenna array.

[0021] In one possible implementation of the first aspect, the first branch is provided in a first module, and the first module can be configured to implement the functionality of the second branch. For example, software can be used to configure the first module so that the first module implements the functionality of the second branch. In this way, the functionality of different branches can be implemented using the same hardware module.

[0022] In a possible implementation of the first aspect above, the first branch is provided in a first module, the second branch is provided in a second module, and the first module and the second module are two independent modules.

[0023] By adopting the above technical solution, the first branch and the second branch are placed in two independent modules, so as to improve the independence of the first branch and the second branch, and the flexibility of the first branch and the second branch.

[0024] In a possible implementation of the first aspect above, the second branch further includes an auxiliary transmission link, the auxiliary transmission link has the same structure as the transmission link, and the auxiliary transmission link multiplexes the second antenna array and filter of the reception link, the auxiliary transmission link and the reception link operate alternately, when the auxiliary transmission link is in an operating state, the second antenna array is used to transmit signals; when the reception link is in an operating state, the second antenna array is used to receive signals.

[0025] A second aspect provides a base station, comprising the sub-band full-duplex communication system as described in any one of the first aspects.

[0026] In a possible implementation of the second aspect above, the base station also includes a baseband processing unit BBU and an active antenna processing unit AAU, the AAU includes a sub-band full-duplex communication system as described in any one of the first aspects, and the BBU is used to perform power reduction scheduling on the downlink resource blocks close to the uplink sub-band edge.

[0027] The third aspect provides a sub-band full-duplex communication method, including: in the SBFD time slot, the baseband signal is downlinked through the digital predistortion DPD, digital-to-analog converter DAC, mixer, power amplifier PA, circulator, filter and first antenna array of the transmitting link; the wireless signal is uplinked through the second antenna array filter, low-noise amplifier, mixer and analog-to-digital converter ADC of the receiving link; the reference link collects the amplified RF signal output by the PA to obtain a reference signal, and performs linear cancellation processing on the received signal output by the receiving link based on the reference signal.

[0028] In a possible implementation of the third aspect above, the reference link collects the amplified RF signal output by the PA to obtain a reference signal, and performs linear cancellation processing on the received signal output by the ADC based on the reference signal, including: collecting the RF signal after amplification by the PA through a coupler; converting the RF signal into a digital signal through a mixer and an analog-to-digital converter; using the digital signal as a reference signal, and performing linear cancellation processing on the received signal output by the receiving link based on the reference signal.

[0029] In a possible implementation of the third aspect, the method further includes filtering the radio frequency signal collected by the coupler using a filter, and sending the filtered radio frequency signal to the mixer. The filter is an adjustable filter or a fixed bandwidth filter.

[0030] In a possible implementation of the third aspect above, the method also includes: in a downlink time slot or an SBFD time slot, one end of the switch unit is connected to the mixer, the other end of the switch unit is connected to the filter, and the first antenna array is used to send a downlink signal; in an uplink time slot, one end of the low-noise amplifier is connected to the circulator, one end of the switch unit is connected to the mixer, the other end of the switch unit is connected to the other end of the low-noise amplifier, and the first antenna array is used to receive an uplink signal.

[0031] In a possible implementation of the third aspect, the first branch includes multiple transmit chains and multiple reference chains, and the second branch includes multiple receive chains. In the first branch, there is a one-to-one correspondence between the first antenna array, the transmit chains, and the reference chains. In the second branch, there is a one-to-one correspondence between the second antenna array and the receive chains.

[0032] In a possible implementation of the third aspect, the first branch is provided in a first module, the second branch is provided in a second module, and the first module and the second module are two independent modules.

[0033] It should be understood that the technical effects brought about by any design in the second to third aspects can refer to the beneficial effects of the corresponding methods provided above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG1 is a schematic diagram of an SBFD time slot structure.

[0035] FIG2 is a schematic diagram of an SBFD timeslot structure provided in an embodiment of the present application.

[0036] FIG3 is a schematic structural diagram of a sub-band full-duplex communication system provided in an embodiment of the present application.

[0037] FIG4 is a schematic structural diagram of another sub-band full-duplex communication system provided in an embodiment of the present application.

[0038] FIG5 is a schematic structural diagram of another sub-band full-duplex communication system provided in an embodiment of the present application.

[0039] FIG6 is a schematic diagram of a signal change provided in an embodiment of the present application.

[0040] FIG7 is a schematic diagram of another SBFD timeslot structure provided in an embodiment of the present application.

[0041] FIG8 is a schematic structural diagram of another sub-band full-duplex communication system provided in an embodiment of the present application.

[0042] FIG9 is a schematic diagram of the module composition of the sub-band full-duplex communication system provided in an embodiment of the present application.

[0043] FIG10 is a module diagram of a base station according to an embodiment of the present application.

[0044] FIG11 is a schematic diagram of power reduction scheduling provided in an embodiment of the present application.

[0045] Description of main component symbols

[0046] Sub-band full-duplex communication system 100

[0047] First Branch Road 10

[0048] Send link 11

[0049] First antenna array 111

[0050] Baseband modem 112

[0051] DPD 113

[0052] DAC 114

[0053] Mixer 115

[0054] PA 116

[0055] Circulator 117

[0056] Filters 118, 212

[0057] Reference Link 12

[0058] Coupler 121

[0059] Mixer 122

[0060] ADC 123, 215

[0061] LIC 124

[0062] Filters 125, 219

[0063] Switch unit 126

[0064] Second Branch Road 20

[0065] Receive link 21

[0066] Second antenna array 211

[0067] Low noise amplifier 213, 127

[0068] Mixer 214

[0069] Auxiliary transmission link 22

[0070] The following specific implementation methods will further illustrate the present application in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0071] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the embodiments of the present application, words such as "exemplary" or "for example" are used to identify examples, illustrations or explanations. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or design schemes. Specifically, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete way.

[0072] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art in the art to which this application pertains. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. It should be understood that, in this application, unless otherwise specified, "a plurality of" refers to two or more than two, and "and / or" includes any and all combinations of one or more of the associated listed items.

[0073] First, the technical terms involved in the embodiments of this application are introduced:

[0074] 1. Sub-band full duplex (SBFD)

[0075] Sub-band full-duplex is achieved by configuring uplink and downlink transmission resources separately on different frequencies in some time slots. Since more uplink and downlink time slots are configured, the uplink and downlink delays can be reduced; the ability to flexibly configure more uplink resources helps to enhance uplink coverage and increase capacity.

[0076] In order to enhance uplink coverage and uplink capacity, existing communication systems have begun to promote the use of sub-band full-duplex technology. This application uses the application of sub-band full-duplex technology to a base station as an example for explanation.

[0077] Among them, Figure 1 is a schematic diagram of a sub-band full-duplex frame structure. Among the ten time slots in Figure 1, each time slot is a frequency-duplexed SBFD time slot that can simultaneously perform uplink UL (i.e., receiving link) and downlink DL (i.e., transmitting link) transmission. As shown in Figure 1, the UL sub-band occupies 4MHz, and the two DL sub-bands occupy 8MHz respectively. Since uplink and downlink transmissions are performed simultaneously in the same time slot, there is mutual influence between the uplink and downlink, especially the influence of the downlink on the uplink, which can easily lead to blocking of the uplink receiving channel and affect the uplink coverage and sensitivity.

[0078] Based on the above problems, an embodiment of the present application provides a sub-band full-duplex communication system, which separates the transmitting and receiving antennas to reduce the mutual influence between the uplink and the downlink, and linearly cancels the received signal of the uplink through linear cancellation technology to remove the self-interference component in the received signal and reduce the impact of the downlink on the uplink.

[0079] Figure 2 is a schematic diagram of an SBFD timeslot structure used in this application. Figure 2 includes five timeslots, with the first through fourth timeslots dividing the entire frequency band into UL and DL subbands. The UL subband can be used for uplink transmission (e.g., X MHz is used for uplink transmission in Figure 2), while the DL subband can be used for downlink transmission. The fifth timeslot uses the entire frequency band for uplink transmission.

[0080] It can be understood that in other embodiments, the number of SBFD time slots may be greater than or less than 5 time slots. The embodiment of the present application only takes 5 time slots as an example for description.

[0081] In the SBFD time slot shown in Figure 2, neither the uplink (UL) nor the downlink (DL) can occupy the entire frequency resource range. The UL subband occupies the center of the frequency band, while the DL subbands are located on both sides of the frequency band.

[0082] In one embodiment, the UL subbands may be symmetrical about the center of the frequency band, such that the bandwidth of the DL lower subband and the bandwidth of the DL upper subband are equal. However, in other embodiments, the UL subbands may be configured anywhere in the frequency band, in which case the bandwidth of the DL lower subband is different from the bandwidth of the DL upper subband.

[0083] It can be understood that in other embodiments, the SBFD time slot may be located in any time slot of the five time slots, that is, any time slot of the five time slots may be used.

[0084] Please refer to Figure 3, which is a schematic diagram of a sub-band full-duplex communication system provided in an embodiment of the present application. In Figure 3, the sub-band full-duplex communication system 100 includes a first branch 10 and a second branch 20. The first branch 10 includes a transmission link 11 and a reference link 12, and the second branch 20 includes a reception link 21. The sub-band full-duplex communication system shown in Figure 3 can apply the SBFD time slot shown in Figure 2. The transmission link 11 is used for downlink transmission signals from the first time slot to the fourth time slot, and the reception link 21 is used for uplink reception signals from the first time slot to the fourth time slot. Both the first branch 10 and the second branch 20 are used for uplink reception signals in the fifth time slot. The number and aperture of the equivalent array antennas are increased to enhance uplink coverage.

[0085] In Figure 3, transmit chain 11 includes a first antenna array 111, and receive chain 21 includes a second antenna array 211. There is a separation of, for example, 50 centimeters between first antenna array 111 and second antenna array 211. During an SBFD timeslot, first antenna array 111 is transmitting while second antenna array 211 is receiving. The physical separation between first antenna array 111 and second antenna array 211 reduces interference from downlink transmission signals on the uplink during the same SBFD timeslot.

[0086] In other embodiments, an isolation member (not shown) is provided between the first antenna array 111 and the second antenna array 211 to increase the isolation between the first antenna array 111 and the second antenna array 211 and reduce interference therebetween.

[0087] The above-mentioned reference link is used to collect the RF signal output after the power amplifier PA116 of the transmission link 11 as a reference signal, and based on the reference signal, use linear cancellation technology to remove the self-interference component in the uplink received signal to further reduce the interference between the downlink transmission signal and the uplink received signal.

[0088] 3 again, the transmission chain 11 further includes: a baseband modem BB Tx 112 , a digital predistortion module DPD 113 , a digital-to-analog converter DAC 114 , a mixer 115 , a power amplifier PA 116 , a circulator CIRC 117 and a filter RF BF 118 .

[0089] For clarity, FIG3 illustrates only a single transmit RF chain. Multiple transmit RF chains may be integrated into the first branch 10. Each transmit RF chain is configured to convert a baseband signal into a transmit RF signal. It will be appreciated that in other embodiments, the number of RF chains in a sub-band full-duplex communication system may be configured as needed. The number of reference chains is the same as the number of transmit chains, and there is a one-to-one correspondence.

[0090] When the sub-band full-duplex communication system 100 transmits a signal: the baseband modem 112 includes a base station transmitter 1121 (BB ​​Tx) for generating a baseband signal for each transmit RF chain. The baseband transmitter 1121 generates a baseband signal for each transmit RF chain; the baseband signal is then sent to the DPD 113, which performs pre-distortion processing on the baseband signal and converts it into an analog signal through the DAC 114.

[0091] The analog signal is then amplified by the power amplifier PA116 and passes through the circulator 117 and the filter 118 in sequence to filter out out-of-band spurious signals. Finally, the energy is radiated into free space by the first antenna array 111.

[0092] The reference link 12 includes a coupler 121, a mixer 122, and an analog-to-digital converter ADC123. The coupler 121 collects the RF signal amplified by the power amplifier PA116 in the transmission link and sends the RF signal to the mixer 122 and the analog-to-digital converter ADC123. After the mixer 122 and the analog-to-digital converter ADC123 process the RF signal, a digital reference signal is obtained. The received signal is then canceled by the LIC124 of the baseband processing unit based on the digital parameter signal, that is, the self-interference component in the uplink received signal is eliminated by linear interference cancellation technology.

[0093] It is understood that in other embodiments, the LIC 124 may be disposed in the second branch 20 . For example, the LIC 124 may be a part of the receiving link 21 . Thus, before the received signal is transmitted to the BBU, the received signal is cancelled by the LIC 124 of the receiving link 21 .

[0094] The receiving chain 21 further includes a filter RF BF 212 , a low noise amplifier LNA 213 , a mixer 214 and an analog-to-digital converter ADC 215 .

[0095] For clarity of illustration, FIG3 shows only a single receive RF chain. Each receive RF chain is configured to convert a received RF signal into a baseband signal. In FIG3 , multiple receive RF chains are integrated into the second branch 20. A sub-band full-duplex communication system may include multiple receive RF chains. Each receive RF chain is configured to down-convert the RF signal received by the second antenna array from RF to baseband.

[0096] When sub-band full communication system 100 receives a signal, second antenna array 211 receives the uplink RF signal. Low-noise amplifier 213 performs low-noise amplification on the filtered signal for uplink transmission. The signal is then sent to mixer 214 and ADC 215. ADC 215 processes the signal from low-noise amplifier 213 to produce a received digital signal.

[0097] LIC124 then uses linear interference cancellation technology to linearly cancel the received signal and the parameter signal to remove the self-interference component of the signal. The reference signal contains the transmitted baseband signal and its nonlinear components and noise. The received signal contains the self-interference signal and the desired signal.

[0098] The sub-band full-duplex communication system 100 uses a reference link 12 to collect the signal amplified by PA 116 in transmit link 11 as a reference signal. This reference signal includes the nonlinearity and noise generated by the downlink transmit signal. Compared to separately collecting the signal processed by filter 118 in transmit link 11 for analog linear cancellation and collecting the baseband signal for digital linear / nonlinear cancellation, this application eliminates the need for nonlinear modeling, reducing cancellation costs. Furthermore, reference link 12 uses a switch to switch between reference channel and receive channel operating modes, reducing hardware implementation costs.

[0099] In some embodiments, the receiving link 21 further includes a filter 219, one end of which is connected to the low noise amplifier LNA 213, and the other end is connected to the mixer 214. In the SBFD time slot, the passband bandwidth of the adjustable filter matches the UL sub-band, reducing the DL sub-band leakage energy and avoiding saturation of the receiving link ADC. In the UL time slot, the passband bandwidth of the adjustable filter is switched to the entire frequency band without affecting the uplink full-band received signal. Since the downlink signal strongly interferes with the uplink receiving link, the receiving link and the reference link have high requirements for the ADC dynamic range, which poses a great challenge to engineering implementation. By adding filters, the dynamic range requirements of the receiving link and the reference link are reduced, which facilitates engineering implementation. When the filters of the receiving link and the reference link are fixed bandwidth filters, only fixed sub-band bandwidth configuration can be supported. When the filters of the receiving link and the reference link are adjustable bandwidth filters, flexible configuration of the UL sub-band bandwidth can be supported.

[0100] In some embodiments, the reference link 12 further includes a filter 125, which receives the analog signal collected by the coupler 121. After filtering the analog signal, the filter 125 sends the signal to the mixer 122 and the ADC 123. The filter 125 may be an adjustable filter. By adding an adjustable filter, the applicable range of the analog-to-digital converter ADC is improved, and the dynamic range of the analog-to-digital converter ADC is avoided from being limited. Of course, in other embodiments, the filter 125 may also be a fixed bandwidth filter.

[0101] Referring to FIG3 , reference link 12 further includes a switch unit 126 and a low-noise amplifier 127. In the first to fourth time slots, filter 125 is connected to mixer 122 via switch unit 126 , i.e., one end of switch unit 126 is connected to filter 125 and the other end is connected to mixer 122. In the fifth time slot, low-noise amplifier 127 is connected to mixer 122 via switch unit 126 , i.e., one end of switch unit 126 is connected to low-noise amplifier 127 and the other end is connected to mixer 122. Low-noise amplifier 127 is connected to circulator 117 and multiplexes the first antenna array 111, filter 118, and circulator 117 in transmit link 11. At this time, the first antenna array 111 is used to receive the uplink signal, and then the received uplink signal is filtered by the filter 118 and amplified by the low noise amplifier 213 for uplink transmission, and then sent to the mixer 122 and ADC123 through the switch unit. ADC123 processes the uplink signal from the low noise amplifier 213 to obtain a digital received signal. In this way, the two ends of the switch unit are connected to different device units, and the first antenna array performs different functions. In the embodiment of the present application, when the switch unit is connected to the low noise amplifier and the mixer, the first antenna array is used to receive the uplink signal. Since the first antenna array and the second antenna array are both used to receive the uplink signal at this time, the uplink coverage is improved.

[0102] Please refer to FIG4 , which is a schematic diagram of a sub-band full-duplex communication system provided in an embodiment of the present application. The sub-band full-duplex communication system in FIG4 is similar to the sub-band full-duplex communication system 100 in FIG3 , except that:

[0103] In the sub-band full-duplex communication system 100 shown in FIG4 , the first branch 10 includes multiple transmit chains 11 and multiple reference chains 12, with each transmit chain 11 corresponding one-to-one to each reference chain 12. The second branch 20 includes multiple receive chains 21, each receive chain 21 being configurable as a receive RF chain, and each transmit chain 11 being configurable as a transmit RF chain. Thus, each receive RF chain or transmit RF chain corresponds one-to-one to a target antenna array, where the target antenna array is the first antenna array or the second antenna array, respectively. In FIG4 , the first branch 10 includes multiple transmit chains 11 and multiple reference chains 12, so the baseband transmitter 1121 of the baseband modem 112 generates a baseband signal for each transmit RF chain.

[0104] In the first to fourth time slots, known as SBFD time slots, the multiple transmit RF chains in the first branch are used for downlink transmission, and the multiple receive RF chains in the second branch are used for uplink reception. In the fifth time slot, the first branch reference link is configured in receive mode, and both the receive RF chains in the second branch are used for uplink reception. Therefore, in the SBFD time slot, the first antenna array of the transmit RF chain is used for transmission, and the second antenna array of the receive RF chain is used for reception. In the fifth time slot, both the first and second antenna arrays are used for reception.

[0105] Furthermore, since in the embodiment of the present application, each antenna corresponds to an RF chain, the independence between the RF chains is relatively strong, which facilitates adjustment of the number of antenna arrays and RF chains according to needs.

[0106] Please refer to FIG5 , which is a schematic diagram of a sub-band full-duplex communication system provided in an embodiment of the present application. The sub-band full-duplex communication system in FIG5 is similar to the sub-band full-duplex communication system in FIG4 , except that:

[0107] The reference link in Figure 5 also includes a filter. In the SBFD timeslot, the bandwidth and position of the UL subbands of different operators vary. The filter is a tunable filter, which adjusts its filtering range based on the bandwidth and position of the UL subband. Adding a tunable filter to the reference link improves the applicability of the sub-band full-duplex communication system. Of course, in other embodiments, the filter can also be a fixed-bandwidth filter.

[0108] Please refer to Figure 6, which is a schematic diagram of signal changes provided in an embodiment of the present application, wherein Figure 6 (a) is the signal spectrum after PA amplification of the first branch collected by the reference link, and Figure 6 (b) is the signal spectrum after processing by the adjustable filter. Then, the signal in Figure (b) is converted into a digital signal after ADC conversion, and then the digital signal is filtered by the digital filter to become the reference signal shown in Figure 6 (c). The reference signal is then canceled with the received signal of the second branch in the BBU or the receiving link. In this way, by adding an adjustable filter to the reference link, the filtering range of the filter can be adjusted according to different needs.

[0109] Please refer to Figure 7, which is a schematic diagram of the structure of another SBFD time slot format provided in an embodiment of the present application. Figure 7 includes five time slots, of which the first time slot is a pure downlink time slot, in which all frequency resources are used for downlink transmission. The second through fourth time slots are SBFD time slots, in which some frequencies are used for uplink transmission and other frequencies are used for downlink transmission. The fifth time slot is a pure uplink time slot, in which all frequencies are used for base station uplink transmission. It will be understood that in other embodiments, the number of SBFD time slots can be greater or less than 5 time slots. This embodiment of the present application only uses 5 time slots as an example for illustration.

[0110] Please refer to Figure 8, which is a schematic diagram of a sub-band full-duplex communication system provided in an embodiment of the present application. The sub-band full-duplex communication system in Figure 8 is similar to the sub-band full-duplex communication system in Figure 5. Sub-band full-duplex communication system 100 includes a first branch 10 and a second branch 20. The first branch 10 includes multiple transmit links 11 and multiple reference links 12, and the second branch 20 includes multiple receive links 21. The difference is that the second branch 20 also includes multiple auxiliary transmit links 22. Thus, in the first time slot in Figure 7, the first branch 10 and the second branch 20 are both used for downlink signal transmission. From the second to the fourth time slots, the transmit link 11 in the first branch 10 is used for downlink signal transmission, the reference link 12 collects the transmit signal as a reference signal, and the second branch 20 is used for uplink signal reception. In the fifth time slot, the first branch 10 and the second branch 20 are both used for uplink signal reception.

[0111] Furthermore, the auxiliary transmission link 22 has the same structure as the transmission link 11. The auxiliary transmission link 22 includes a digital-to-analog converter DAC, a mixer, a power amplifier PA, a circulator, a filter and an antenna array. The receiving link 21 and the auxiliary transmission link 22 multiplex the circulator, filter and antenna array.

[0112] The receiving link 21 and the auxiliary transmitting link 22 are controlled to work alternately according to the base station time slot configuration. For example, in the first time slot, the auxiliary transmitting link 22 is working, and the second antenna array 211 is used to send downlink signals; in the second to fourth time slots, the receiving link 21 is working, and the receiving link 21 is used to receive uplink signals; in the fifth time slot, the receiving link 21 is working, and the receiving link 21 is used to receive uplink signals.

[0113] Please refer to Figure 9, which is a schematic diagram of a sub-band full-duplex communication system provided in an embodiment of the present application. The sub-band full-duplex communication system in Figure 9 is similar to the sub-band full-duplex communication system in Figure 5, except that the embodiment of Figure 5 is implemented inside a base station module. Figure 9 integrates the first branch shown in Figure 5 into a module, and then another module with the same hardware as the module can be configured by software to implement the function of the second branch. Then, two independent and identical hardware modules are spliced ​​together to achieve the separation of the transmitting and receiving antennas. The two modules are controlled by software to support the sub-band full-duplex working mode. In this way, a single module can work in TDD mode, and two modules spliced ​​together can work in sub-band full-duplex mode.

[0114] In other embodiments, the sub-band full-duplex communication system includes a first branch and a second branch, wherein the first branch is located in a first module and the second branch is located in a second module, and the first module and the second module are two independent modules. Thus, by placing the first branch and the second branch in different modules, separation of transmission and reception can be achieved.

[0115] Please refer to FIG. 9 , in which the first module and the second module are respectively connected to the baseband processing unit BBU.

[0116] Please refer to Figure 10, which is a modular schematic diagram of a base station provided in an embodiment of the present application. The base station includes a baseband processing unit (BBU) and an active antenna processing unit (AAU). The AAU includes the sub-band full-duplex communication system described in the above embodiment. The BBU and AAU communicate and transmit data via the enhanced Common Public Radio Interface (eCPRI).

[0117] In the above embodiment, as shown in Figure 11, the sub-band full-duplex communication system uses sub-band full-duplex technology. During the SBFD timeslot, the downlink transmit signal affects the uplink receive signal, resulting in strong blockage of the receive signal. This blockage is affected by phase noise in the receive link, raising the noise floor of the resource blocks in the UL sub-band that border the DL sub-band. The BBU adaptively adjusts the transmit power based on the actual transmission conditions of each channel or signal and UE feedback information, reducing the transmit power of the DL resource blocks (RBs) near the edge of the UL sub-band while minimizing the impact on downlink services.

[0118] Specifically, the BBU is used to perform power reduction scheduling on downlink RBs close to the uplink sub-band edge, so as to reduce the impact of phase noise on the increase of the UL sub-band edge noise floor.

[0119] In some embodiments, the base station may be a base station supporting Massive MIMO.

[0120] An embodiment of the present application further provides a sub-band full-duplex communication method, which can be applied to the sub-band full-duplex communication system described in any of the above embodiments.

[0121] The sub-band full-duplex communication method includes: in the SBFD time slot, sequentially transmitting the baseband signal via the digital predistortion DPD, digital-to-analog converter DAC, mixer, power amplifier PA, circulator, filter, and first antenna array of the transmitting link; transmitting the radio frequency signal via the second antenna array, filter, low-noise amplifier, mixer, and analog-to-digital converter ADC of the receiving link; and collecting the radio frequency signal output by the PA as a reference signal through the reference link, and performing linear cancellation processing on the received signal output by the ADC of the receiving link based on the reference signal.

[0122] In some embodiments, the reference link collects the radio frequency signal output by the PA as a reference signal, and performs linear cancellation processing on the received signal output by the receiving link ADC according to the reference signal, including:

[0123] collecting the radio frequency signal after amplification and processing by the PA through a coupler;

[0124] The RF signal is converted into a digital signal by a mixer and an analog-to-digital converter;

[0125] The LIC uses the digital signal as a reference signal and performs linear cancellation processing on the reception signal output by the reception link according to the reference signal.

[0126] The LIC can be set in the BBU or in the receiving link.

[0127] In some embodiments, the method further comprises:

[0128] The radio frequency signal collected by the coupler is filtered by a filter to reduce the energy of the DL sub-band signal and avoid limiting the dynamic range of the ADC.

[0129] In some embodiments, the method further comprises:

[0130] In a downlink timeslot or an SBFD timeslot, one end of the switch unit is connected to the mixer, the other end of the switch unit is connected to the filter, and the first antenna array is used to send a downlink signal;

[0131] In the uplink time slot, one end of the low noise amplifier is connected to the circulator, one end of the switch unit is connected to the mixer, and the other end of the switch unit is connected to the other end of the low noise amplifier. The first antenna array is used to receive uplink signals.

[0132] In some embodiments, there are multiple transmitting chains and multiple receiving chains, and the multiple transmitting chains and the multiple receiving chains are configured as multiple transmitting RF chains and multiple receiving RF chains, each receiving RF chain is configured to convert a received RF signal into a baseband signal, and each transmitting RF chain is configured to convert a baseband signal into a RF transmitting signal;

[0133] The multiple receiving RF chains and the multiple transmitting RF chains have a one-to-one correspondence with the target antenna array, and the target antenna array may be the first antenna array or the second antenna array.

[0134] In some embodiments, the first branch is provided in a first module, and the first module can be configured to implement the function of the second branch. For example, software can be used to configure the first module so that the first module implements the function of the second branch. In this way, the functions of different branches can be implemented using the same hardware module.

[0135] In some embodiments, the first branch is provided in a first module, the second branch is provided in a second module, and the first module and the second module are two independent modules.

[0136] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of hardware embodiments, software embodiments, or embodiments in combination with software and hardware. Moreover, the application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program codes. These computer program codes can be stored in a computer-readable memory that can guide a computer or other programmable data processing equipment to work in an ad hoc manner.

[0137] In addition, an embodiment of the present application also provides a device, which can specifically be a chip, component or module, and the device may include a connected processor and memory; wherein the memory is used to store computer-executable instructions, and when the device is running, the processor can execute the computer-executable instructions stored in the memory to enable the chip to execute the network congestion control method in the above-mentioned method embodiments.

[0138] Through the description of the above implementation methods, technical personnel in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0139] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the module or module division is only a logical function division. In actual implementation, there may be other division methods, such as multiple modules or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0140] Modules described as separate components may or may not be physically separate, and components shown as modules may be one physical module or multiple physical modules, that is, they may be located in one place or distributed in multiple places. Some or all of the modules may be selected according to actual needs to achieve the purpose of the present embodiment.

[0141] In addition, the functional modules in the various embodiments of the present application may be integrated into a processing module, or each module may exist physically separately, or two or more modules may be integrated into a single module. The above-mentioned integrated modules may be implemented in the form of hardware or software functional modules.

[0142] If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, the technical solution of the embodiment of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a device (which can be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0143] The above is only a specific embodiment of the present application, but the scope of protection of this application is not limited to this. Any changes or substitutions within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A sub-band full-duplex communication system, characterized in that: include: The first branch includes a transmission link and a reference link, wherein the transmission link includes a digital predistortion DPD, a digital-to-analog converter DAC, a mixer, a power amplifier PA, a circulator, a filter and a first antenna array connected in sequence; The second branch includes a receiving link, which includes a second antenna array, a filter, a low-noise amplifier, a mixer, and an analog-to-digital converter (ADC) connected in sequence; the receiving link is used to down-convert the wireless signal at the antenna port of the second antenna array and sample it to obtain a digital received signal; The reference link is used to collect the radio frequency signal output by the PA of the transmitting link, use the radio frequency signal as a reference signal, and perform linear cancellation processing on the digital receiving signal output by the receiving link based on the reference signal.

2. The sub-band full-duplex communication system according to claim 1, wherein: The reference link includes a coupler, a mixer, and an analog-to-digital converter connected in sequence. The coupler is used to collect the radio frequency signal processed by the PA. The mixer and the analog-to-digital converter down-convert the radio frequency signal and convert it into a digital signal so that the digital signal can be used as a reference signal. The digital reception signal output by the ADC of the receiving link is linearly cancelled based on the reference signal.

3. The sub-band full-duplex communication system according to claim 2, wherein: The reference link further includes a filter, one end of the filter is connected to the coupler, and the other end of the filter is connected to the mixer.

4. The sub-band full-duplex communication system according to claim 3, wherein: The reference link further includes a switch unit and a low noise amplifier, one end of the switch unit is connected to the mixer, and one end of the low noise amplifier is connected to the circulator; When it is a downlink timeslot or an SBFD timeslot, the other end of the switch unit is connected to the filter, and the first antenna array is used to send a downlink signal; During an uplink timeslot, the other end of the switch unit is connected to the low noise amplifier, and the first antenna array is used to receive uplink signals.

5. The sub-band full-duplex communication system according to any one of claims 1 to 4, characterized in that: The first branch includes multiple transmitting links and multiple reference links, and the second branch includes multiple receiving chains. In the first branch, the first antenna array, the transmitting link, and the reference link are in a one-to-one correspondence, and in the second branch, the second antenna array and the receiving link are in a one-to-one correspondence.

6. The sub-band full-duplex communication system according to claim 1, wherein: The receiving chain further includes a filter, one end of the filter is connected to the low noise amplifier, and the other end of the filter is connected to the mixer.

7. The sub-band full-duplex communication system according to claim 5, wherein: The first branch is provided in a first module, and the first module can be configured to implement the function of the second branch.

8. The sub-band full-duplex communication system according to claim 1, wherein: The first branch is provided in a first module, and the second branch is provided in a second module. The first module and the second module are two independent modules.

9. The sub-band full-duplex communication system according to claim 5, wherein: The second branch also includes an auxiliary transmission link, which has the same structure as the transmission link, and the auxiliary transmission link multiplexes the second antenna array and filter of the receiving link. The auxiliary transmission link and the receiving link work alternately. When the auxiliary transmission link is in a working state, the second antenna array is used to send signals; when the receiving link is in a working state, the second antenna array is used to receive signals.

10. A base station, characterized in that: The invention comprises the sub-band full-duplex communication system according to any one of claims 1 to 9.

11. The base station according to claim 10, wherein The base station further includes a baseband processing unit BBU and an active antenna processing unit AAU, the AAU includes the sub-band full-duplex communication system according to any one of claims 1 to 7, and the BBU is used to reduce power scheduling for downlink resource blocks close to the uplink sub-band edge.

12. A sub-band full-duplex communication method, characterized in that: include: In the SBFD timeslot, the baseband signal is transmitted downlink through the digital predistortion DPD of the transmission link, the digital-to-analog converter DAC, the mixer, the power amplifier PA, the circulator, the filter and the first antenna array. The wireless signal is transmitted uplink via the second antenna array, filter, low noise amplifier, mixer and analog-to-digital converter (ADC) of the receiving link in sequence; The reference link collects the radio frequency signal output by the PA as a reference signal, and performs linear cancellation processing on the received signal output by the receiving link according to the reference signal.

13. The sub-band full-duplex communication method according to claim 12, wherein: The reference link collects the radio frequency signal output by the PA to obtain a reference signal, and performs linear cancellation processing on the received signal output by the ADC of the receiving link according to the reference signal, including: collecting the radio frequency signal after amplification and processing by the PA through a coupler; Converting the radio frequency signal into a digital signal through a mixer and an analog-to-digital converter; The LIC uses the digital signal as a reference signal and performs linear cancellation processing on the reception signal output by the reception link according to the reference signal.

14. The sub-band full-duplex communication method according to claim 13, wherein: The method further comprises: The radio frequency signal collected by the coupler is filtered by a filter, and the filtered radio frequency signal is transmitted to the mixer.

15. The sub-band full-duplex communication method according to claim 14, wherein: The method further comprises: In the SBFD timeslot, one end of the switch unit is connected to the mixer, the other end of the switch unit is connected to the filter, and the first antenna array is used to send a downlink signal; In the uplink time slot, one end of the low noise amplifier is connected to the circulator, one end of the switch unit is connected to the mixer, and the other end of the switch unit is connected to the other end of the low noise amplifier. The first antenna array is used to receive uplink signals.

16. The sub-band full-duplex communication method according to any one of claims 12 to 15, characterized in that: The first branch includes multiple transmitting links and multiple reference links, and the second branch includes multiple receiving chains. In the first branch, the first antenna array, the transmitting link, and the reference link are in a one-to-one correspondence, and in the second branch, the second antenna array and the receiving link are in a one-to-one correspondence.

17. The sub-band full-duplex communication method according to claim 16, wherein: The first branch is provided in a first module, and the first module can be configured to implement the function of the second branch.

18. The sub-band full-duplex communication method according to claim 16, wherein: The first branch is provided in a first module, and the second branch is provided in a second module. The first module and the second module are two independent modules.

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