Data transmission method and data transmission system

Abstract

The application relates to a data transmission method and a data transmission system, the system comprising a first processing unit and a plurality of second processing units, the method comprising: the first and second processing units sending downlink data, first user information and first beamforming weights to a second processing unit at a next level; the second processing unit processing the downlink data according to the first user information and the first beamforming weights to obtain downlink air interface data. The first and second processing units send second user information and second beamforming weights to a second processing unit at a next level; the second processing unit processes new uplink data according to uplink air interface data and / or uplink data, the second user information and the second beamforming weights, and sends the new uplink data to a second / first processing unit at a previous level. The method enables the wireless front-haul interface of a chain type architecture to multiplex the limited transmission bandwidth resources of a single optical fiber and optical module, and enables optimal wireless air interface performance.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a data transmission method and a data transmission system. Background Technology

[0002] With the development of 4G and 5G, traditional distributed antenna systems in mobile communication systems are gradually transitioning to digital distributed base stations. This is due to factors such as the ever-increasing capacity demands and the need to introduce digital signal processing capabilities at radio frequency (RF) transmission points to facilitate their operation and maintenance. Currently, there are two main architectures for digital distributed base stations. The star architecture supports multiple operating modes, including cell merging, selective transceiver, spatial multiplexing, and distributed massive MIMO, but higher-performance modes consume more fiber optic resources. While the chain architecture has advantages in cost and engineering, its transmission bandwidth resources are limited. To maintain lower data transmission costs, data transmission performance must be sacrificed, thus leaving room for improvement. Summary of the Invention

[0003] In view of this, a data transmission method and a data transmission system are proposed. According to the data transmission method of the embodiments of this application, the data transmission system of the chain architecture can reuse the limited transmission bandwidth resources of a single optical fiber and a single optical module, thereby reducing data transmission costs and improving data transmission performance.

[0004] In a first aspect, embodiments of this application provide a data transmission method applied to a data transmission system. The data transmission system includes a first processing unit and multiple second processing units cascaded via a single optical fiber. An enhanced general public wireless interface (GPWAN) is used between the first processing unit and the next-level second processing unit, and between adjacent levels of second processing units. The method includes: the first processing unit generating a first beamforming weight corresponding one-to-one with each of the multiple second processing units, and transmitting downlink data, first user information related to the multiple second processing units, and the first beamforming weight to the next-level second processing unit; for each second processing unit, the first... The second processing unit sends the downlink data, along with first user information and first beamforming weights related to the next-to-last second processing unit, to the next-level second processing unit. For each second processing unit, when the first user information and first beamforming weights received by the second processing unit include first user information and first beamforming weights related to itself, the second processing unit processes the received downlink data according to the first user information and first beamforming weights related to itself to obtain downlink air interface data. For each second processing unit, when the second processing unit obtains the downlink air interface data, it sends the downlink air interface data to the user equipment through the air interface.

[0005] According to the data transmission method of this application embodiment, a first processing unit generates first shaping weights corresponding one-to-one with a plurality of second processing units, and sends downlink data, first user information related to the plurality of second processing units, and first shaping weights to the next-level second processing unit, so that the next-level second processing unit can obtain the downlink data to be processed and the first user information and first shaping weights to be used when processing the downlink data; by each second processing unit sending downlink data, as well as the first user information and first shaping weights related to the next-to-last level second processing unit, each second processing unit can obtain downlink data and the first user information and first shaping weights related to itself, and the amount of data transmitted over the optical fiber is reduced; by including the first user information and first shaping weights related to itself in the first user information and first shaping weights received by each second processing unit, the received downlink data is processed according to the first user information and first shaping weights related to itself to obtain downlink air interface data, so that the downlink data processing work can be completed, and the downlink air interface data can be sent to the user equipment through the air interface, thereby completing the transmission of downlink data. In the data transmission system employing this method, a first processing unit and multiple second processing units are cascaded via a single optical fiber, thus enabling a chain-like architecture. Since an enhanced universal public radio interface (GPRS) is used between the first processing unit and the next-level second processing unit, and between adjacent levels of second processing units, this enhanced GPRS allows each second processing unit to process downlink data based on first user information and a first shaping weight. This enables selective processing of downlink data, unlike existing GPRS interfaces which cannot utilize the first user information and first shaping weight at the second processing unit level. In other words, each second processing unit can distinguish different data from different users based on the first user information and the first shaping weight, reducing noise and improving the signal-to-noise ratio. In this context, the data transmission method according to the embodiments of this application allows the chain-like data transmission system to reuse the limited transmission bandwidth resources of a single optical fiber and a single optical module, thereby reducing data transmission costs and improving data transmission performance.

[0006] According to the first aspect, in a first possible indication of the data transmission method, the first shaping weight includes information on whether the user is related to each second processing unit, and the first processing unit generates a first shaping weight corresponding to each of the plurality of second processing units, including: determining the downlink operating mode of the data transmission system according to configuration information; determining whether the user is related to each second processing unit; and generating a first shaping weight corresponding to each second processing unit for the user according to the determined downlink operating mode for each second processing unit related to the user.

[0007] In this way, it is possible to determine whether a user is related to a certain second processing unit simply by using the first shaping weight, and to refresh the first shaping weight in a timely manner.

[0008] According to the first aspect, or the first possible indication of the first aspect, the second possible indication is that the first user information includes information indicating whether the user is related to each second processing unit.

[0009] In this way, it is possible to determine whether a user is related to a certain second processing unit based on the first user information, without refreshing the first shaping weight.

[0010] According to the first aspect, or any possible indication of the first aspect above, the step of processing the received downlink data according to the first user information and the first shaping weight associated with itself to obtain downlink air interface data includes: when the first user information or the first shaping weight associated with itself indicates that the user is associated with itself, using the first shaping weight associated with itself to convert the downlink data from the flow domain to the beam domain to obtain downlink baseband data in the beam domain, wherein the downlink air interface data is radio frequency data converted from the downlink baseband data.

[0011] In this way, the conversion from downlink data to downlink air interface data can be completed. The converted downlink air interface data can then be sent to the user equipment via the air interface, thus completing the downlink transmission of downlink data.

[0012] According to the first possible indication method of the first aspect, the downlink operating mode of the data transmission system includes a cell merging mode. In the cell merging mode, each second processing unit processes the downlink data. The first shaping weight corresponding to each second processing unit is the same. Each second processing unit sends the downlink air interface data to the user equipment through the air interface. The maximum number of beam domains is the number of antennas of the plurality of second processing units.

[0013] In this way, the data transmission method of this application embodiment can achieve the effect of cell merging.

[0014] According to a first possible indication of the first aspect, the downlink operating mode of the data transmission system includes a selective transmit / receive mode, in which at least one second processing unit processes the downlink data, and the air interface used by the at least one second processing unit is not allowed to be used by other users of other second processing units besides the user, and the at least one second processing unit transmits the downlink air interface data to the user equipment through the air interface; the maximum number of beam domains is the number of antennas of the plurality of second processing units.

[0015] In this way, the data transmission method of this application embodiment can achieve the effect of selective sending and receiving, thereby improving the flexibility and performance of the data transmission method.

[0016] According to a first possible indication of the first aspect, the downlink operating mode of the data transmission system includes a spatial division multiplexing mode, in which at least one second processing unit processes the downlink data, and the air interface used by the at least one second processing unit is allowed to be used by other users of other second processing units besides the user, and the at least one second processing unit transmits the downlink air interface data to the user equipment through the air interface; the maximum number of beam domains is the product of the number of antennas of the plurality of second processing units and a preset spatial division multiplexing coefficient.

[0017] In this way, the data transmission method of this application embodiment can achieve the effect of spatial multiplexing, thereby improving the flexibility and performance of the data transmission method.

[0018] According to a first possible indication method of the first aspect, the downlink operating mode of the data transmission system includes a distributed massive MIMO mode, in which at least one second processing unit processes the downlink data, and the first processing unit generates a first shaping weight corresponding to each beam domain in a one-to-one manner with the at least one second processing unit; the maximum number of beam domains is associated with the number of antennas of the plurality of second processing units.

[0019] In this way, the data transmission method of this application embodiment can achieve the effect of a distributed large-scale antenna array, improving the flexibility and performance of the data transmission method.

[0020] Secondly, embodiments of this application provide a data transmission method applied to a data transmission system. The data transmission system includes a first processing unit and multiple second processing units cascaded via a single optical fiber. An enhanced general public wireless interface is used between the first processing unit and the next-level second processing unit, and between adjacent levels of second processing units. The method includes: the first processing unit generating second beamforming weights corresponding one-to-one with the multiple second processing units, and sending second user information and the second beamforming weights related to the multiple second processing units to the next-level second processing unit; for each second processing unit, the second processing unit sends data to the next-level second processing unit... Send the second user information and second shaping weights related to the second processing unit from the next level to the last level; for each second processing unit, when the second processing unit has not received uplink data, the second processing unit processes the received uplink air interface data and the second user information and second shaping weights related to itself to obtain uplink data; when the second processing unit receives uplink data, the second processing unit processes the received uplink air interface data, uplink data and the second user information and second shaping weights related to itself to obtain new uplink data; for each second processing unit, the second processing unit sends the processed uplink data to the second processing unit of the next level or the first processing unit of the previous level.

[0021] According to the data transmission method of this application embodiment, a first processing unit generates second shaping weights corresponding one-to-one with a plurality of second processing units, and sends second user information and second shaping weights related to the plurality of second processing units to the next-level second processing unit, so that the next-level second processing unit of the first processing unit can obtain the second user information and second shaping weights needed when processing uplink data; by each second processing unit sending the second user information and second shaping weights related to the next-level to the last-level second processing unit to the next-level second processing unit, each second processing unit can obtain the second user information and second shaping weights related to itself, and the amount of data transmitted over the optical fiber is reduced; for each second processing unit, when the second processing unit does not receive When uplink data arrives, the second processing unit processes the received uplink air interface data and its associated second user information and second shaping weights to obtain uplink data. Upon receiving uplink data, the second processing unit processes the received uplink air interface data, the uplink data, its associated second user information, and the second shaping weights to obtain new uplink data, thus completing the uplink data processing. The second processing unit then sends the processed uplink data to the next-level second processing unit or the previous-level first processing unit to complete the uplink data transmission. The uplink data output by each second processing unit is the merged uplink data output by the next-level to the last-level second processing unit, which reduces the amount of data transmitted over the optical fiber. In the data transmission system employing this method, a first processing unit and multiple second processing units are cascaded via a single optical fiber, thus enabling a chain-like architecture. Since an enhanced universal public wireless interface (GPWI) is used between the first processing unit and the next-level second processing unit, and between adjacent levels of second processing units, this enhanced GPWI allows each second processing unit to process uplink data based on second user information and second shaping weights. This allows the data transmission system to selectively process uplink data, unlike existing GPWIs which cannot utilize second user information and second shaping weights for processing at the second processing unit level. In other words, each second processing unit can distinguish different data from different users based on second user information and second shaping weights, reducing noise and improving the signal-to-noise ratio. In this context, the data transmission method according to the embodiments of this application enables the chain-like data transmission system to reuse the limited transmission bandwidth resources of a single optical fiber and a single optical module, thereby reducing data transmission costs and improving data transmission performance.

[0022] According to the second aspect, in a first possible indication of the data transmission method, the second shaping weight includes information indicating whether the user is related to each second processing unit. The first processing unit generates a second shaping weight corresponding to each of the plurality of second processing units, including: determining the uplink operating mode of the data transmission system according to configuration information; determining whether the user is related to each second processing unit; and generating a second shaping weight corresponding to the user for each second processing unit related to the user according to the determined uplink operating mode.

[0023] In this way, it is possible to determine whether a user is related to a certain second processing unit simply by using the first shaping weight, and to refresh the second shaping weight in a timely manner.

[0024] According to the second aspect, or the first possible indication of the second aspect, the second possible indication is that the second user information includes information for indicating whether the user is related to each second processing unit.

[0025] In this way, it is possible to determine whether a user is associated with a certain second processing unit using the second user information, without refreshing the second shaping weight.

[0026] According to the first or second possible indication method of the second aspect, when the second processing unit does not receive uplink data, the second processing unit processes the received uplink air interface data and the second user information and second beamforming weights associated with itself to obtain uplink data; when the second processing unit receives uplink data, the second processing unit processes the received uplink air interface data, the uplink data, the second user information and second beamforming weights associated with itself to obtain new uplink data, including: when the second user information or second beamforming weights associated with itself indicate that the user is associated with itself, the second processing unit converts the uplink air interface data into uplink baseband data in the beam domain, and uses the second beamforming weights associated with itself to convert the uplink baseband data from the beam domain to the flow domain to obtain enhanced general public radio interface data in the flow domain; when the second processing unit does not receive uplink data, the enhanced general public radio interface data is used as uplink data; when the second processing unit receives uplink data, the received uplink data and the enhanced general public radio interface data are merged, and the merged data is used as new uplink data.

[0027] In this way, the conversion from uplink air interface data to uplink data can be completed. The converted uplink data can then be sent to the cascaded upstream stage via the air interface, thus completing the uplink transmission of the uplink data.

[0028] According to the second aspect, or the first or second possible indication of the second aspect, the merging process of the received uplink data and the enhanced general public radio interface data includes: merging the data corresponding to the same user and processed from uplink baseband data in the same beam domain and uplink air interface data in the same frequency domain in the received uplink data and the enhanced general public radio interface data processed by itself; or merging the data corresponding to the same user and in the same flow domain and with the same bit in the received uplink data and the enhanced general public radio interface data processed by itself.

[0029] In this way, data can be merged to obtain upstream data with lower redundancy.

[0030] According to the first possible indication method of the second aspect, the uplink operating mode of the data transmission system includes a cell merging mode. In the cell merging mode, each second processing unit processes the uplink air interface data. The second shaping weights corresponding to each second processing unit are the same. Each second processing unit receives the uplink air interface data from the user equipment through the air interface. The maximum number of beam domains is the number of antennas of the plurality of second processing units.

[0031] In this way, the data transmission method of this application embodiment can achieve the effect of cell merging.

[0032] According to the first possible indication of the second aspect, the uplink operating mode of the data transmission system includes a selected transmit / receive mode, in which at least one second processing unit processes the uplink air interface data, and the air interface used by the at least one second processing unit is not allowed to be used by other users of other second processing units besides the user, and the at least one second processing unit receives the uplink air interface data from the user equipment through the air interface; the maximum number of beam domains is the number of antennas of the plurality of second processing units.

[0033] In this way, the data transmission method of this application embodiment can achieve the effect of selective sending and receiving, thereby improving the flexibility and performance of the data transmission method.

[0034] According to the first possible indication of the second aspect, the uplink operating mode of the data transmission system includes a spatial division multiplexing mode, in which at least one second processing unit processes the uplink air interface data, and the air interface used by the at least one second processing unit is allowed to be used by other users of other second processing units besides the user, and the at least one second processing unit receives the uplink air interface data from the user equipment through the air interface; the maximum number of beam domains is the product of the number of antennas of the plurality of second processing units and a preset spatial division multiplexing coefficient.

[0035] In this way, the data transmission method of this application embodiment can achieve the effect of spatial multiplexing, thereby improving the flexibility and performance of the data transmission method.

[0036] According to the first possible indication method of the second aspect, the uplink operating mode of the data transmission system includes a distributed massive MIMO mode, in which at least one second processing unit processes the uplink air interface data, and the first processing unit generates a second shaping weight corresponding to at least one second processing unit for each beam domain; the maximum number of beam domains is associated with the total number of antennas of the plurality of second processing units.

[0037] In this way, the data transmission method of this application embodiment can achieve the effect of a distributed large-scale antenna array, improving the flexibility and performance of the data transmission method.

[0038] Thirdly, embodiments of this application provide a data transmission system including a first processing unit and multiple second processing units cascaded through a single optical fiber. An enhanced general public wireless interface is used between the first processing unit and the next-level second processing unit, and between adjacent two-level second processing units. The system is configured to implement one or more of the data transmission methods of the first aspect or multiple possible implementations of the first aspect, and / or implement one or more of the data transmission methods of the second aspect or multiple possible implementations of the second aspect.

[0039] These and other aspects of this application will become more apparent in the description of the following embodiments(s). Attached Figure Description

[0040] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this application together with the specification and serve to explain the principles of this application.

[0041] Figure 1 A schematic diagram of the structure of a star-shaped digital distributed base station in the prior art is shown.

[0042] Figure 2 A schematic diagram illustrating the structure of a chain-like architecture digital distributed base station in the prior art.

[0043] Figure 3 A schematic diagram of the fronthaul interface of a digital distributed base station is shown.

[0044] Figure 4 This diagram illustrates a prior art chain-architecture digital distributed base station based on time-domain signal combining.

[0045] Figure 5 This diagram illustrates a star-shaped digital distributed base station based on frequency domain signal combining, a concept from the prior art.

[0046] Figure 6 This illustrates an exemplary application scenario of the data transmission method according to embodiments of this application.

[0047] Figure 7 A schematic diagram showing the structure of a data transmission system according to an embodiment of this application is provided.

[0048] Figure 8 The diagram illustrates a flow chart of a data transmission method according to an embodiment of this application, specifically for downlink data transmission.

[0049] Figure 9 The diagram illustrates a flow chart of a data transmission method according to an embodiment of this application, specifically for uplink data transmission. Detailed Implementation

[0050] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0051] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0052] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0053] The following explains the terms used in this article.

[0054] Fronthaul Interface: The fronthaul interface is the traditional interface between the building baseband unit (BBU) and the remote radio unit (RRU). Typical fronthaul interface specifications include the Common Public Radio Interface (CPRI) specification and the Enhanced Common Public Radio Interface (eCPRI) specification. Although other naming methods may exist, they are essentially similar.

[0055] The Common Public Radio Interface (CPRI) is defined as the interface between a wireless base station, which is divided into an Indoor Baseband Processing Unit (BBU) and a Remote Radio Unit (RRU). The CPRI transmits only time-domain signals.

[0056] Enhanced Common Radio Interface (eCPRI): The enhanced Common Radio Interface (eCPRI) is also the interface between the Indoor Baseband Processing Unit (BBU) and the Radio Remote Unit (RRU). It is an enhancement of the Common Radio Interface (CPRI) and can transmit various forms of signals, such as time-domain signals, beam-level frequency-domain signals, and symbol-level current-domain signals.

[0057] Besides macro base station coverage, mobile communication systems also cover indoor and residential areas. Previously, solutions for the latter primarily relied on distributed antenna systems. The core advantage of distributed antenna systems is that all radio frequency (RF) signal transmission points within the coverage area belong to the same cell, minimizing interference between different RF signal transmission points, reducing handover occurrences, and lowering the demand for base station resources. However, the entire distributed antenna system coverage area can only share the channel capacity of a single cell. With the development of 4G and 5G mobile networks, distributed antenna systems are gradually transitioning to digital distributed base stations. This is due to factors such as the ever-increasing capacity demands and the introduction of digital signal processing capabilities at RF signal transmission points to facilitate their operation and maintenance. Overall, digital distributed base stations have two main architectures.

[0058] The first architecture of digital distributed base stations adopts a star topology. Figure 1 A schematic diagram illustrating the structure of a star-shaped digital distributed base station in the prior art is shown. Figure 1As shown, in a star-topology digital distributed base station, a hub is used as an expansion unit, and several remote radio units (RRUs) can be connected in a star configuration under each hub. Under this architecture, the digital distributed base station can employ various operating modes, including cell merging, selective transmit / receive, spatial division multiplexing, and massive MIMO (multi-input multi-output) antenna arrays, while maintaining multiple RRUs belonging to the same cell. Cell merging typically replicates or merges information from different RRUs at the hub location, and its wireless performance is closer to that of a distributed antenna system. Selective transmit / receive mode improves wireless performance by allowing users to select one or more RRUs for transmit / receive. Spatial division multiplexing further enhances performance by providing the gains from multi-user multiplexing, building upon selective transmit / receive mode. Massive MIMO further enhances performance by utilizing time synchronization and phase alignment on top of spatial division multiplexing, while maintaining capacity and consistent user experience across the coverage area.

[0059] While the wireless performance of each of the above working modes is gradually improved, the resource consumption of the indoor baseband processing unit (BBU) and hub is also increased. This is precisely the embodiment of the evolvability and performance advantages of digital distributed base stations. However, the star connection between the hub and the remote radio unit (RRU) also consumes more fiber optic resources and increases the complexity of construction.

[0060] The second architecture of digital distributed base stations adopts a chain-like architecture. Figure 2 A schematic diagram illustrating the structure of a chain-like architecture digital distributed base station in the prior art is shown. Figure 2As shown. Its main feature is that different Remote Radio Units (RRUs) are cascaded and networked together. In this architecture, a hub is an optional device. The chain architecture is closer to the needs of actual deployment scenarios, thus having advantages in cost and engineering. Moreover, while maintaining multiple RRUs belonging to the same cell, if the transmission bandwidth of a single optical fiber and a single optical module is not considered, the chain architecture can logically achieve the same functions and performance as the star architecture. That is, it can also realize cell merging, selective transmission and reception, spatial multiplexing, distributed massive MIMO, and other working modes, and its performance can be the same as that of a digital distributed base station using a star architecture. The problem lies in the fact that after multiple Remote Radio Units (RRUs) are cascaded, it's equivalent to having only one fiber connecting the Baseband Processing Unit (BBU) and multiple RRUs. Without special handling, the required transmission bandwidth resources of a single fiber and a single optical module (each end of the fiber connects to an optical module) will have a cumulative effect. For example, if each RRU requires 25G of fronthaul interface bandwidth, then cascading four RRUs would require 100G of bandwidth, and cascading eight RRUs would require 200G of bandwidth. The transmission bandwidth resources of a single fiber and a single optical module are limited, especially when cost-effectiveness is a consideration. Therefore, how to reuse the limited transmission bandwidth resources of a single fiber and a single optical module for the fronthaul interfaces between cascaded RRUs and between cascaded RRUs and the indoor baseband processing unit (BBU) becomes a critical issue.

[0061] The bandwidth requirements of the fronthaul interface are closely related to the fronthaul interface specification adopted, which mainly includes two categories: Common Public Radio Interface (CPRI) and Enhanced Common Public Radio Interface (eCPRI). Figure 3 A schematic diagram of the fronthaul interface of a digital distributed base station is shown. Figure 3As shown, the Common Public Radio Interface (CPRI) is a baseband-to-radio interface, with signals in a time-domain format. The Enhanced Common Public Radio Interface (eCPRI), an enhancement of CPRI, further incorporates beam-level frequency domain and symbol-level current domain formats. Generally speaking, any interface located within the physical layer (PHY) in the diagram can be referred to as the Enhanced Common Public Radio Interface (eCPRI) (eCPRI fronthaul interface). In existing technologies using the Common Public Radio Interface (CPRI), data must undergo operations such as encoding, rate matching, scrambling, modulation, layer mapping, precoding, resource mapping, stream-to-beam domain conversion (beamforming), inverse fast Fourier transform, and insertion of a cyclic prefix by the indoor baseband processing unit (BBU) to obtain baseband data. Then, the remote radio unit (RRU) converts the baseband data into radio frequency (RF) data before it can be transmitted by the antenna. For RF data received through the antenna, it must first be converted into baseband data by the RRU, and then the indoor baseband processing unit (BBU) performs operations such as removing the cyclic prefix, fast Fourier transform, beam-to-stream domain conversion, resource demapping, channel estimation, combining, equalization, inverse Fourier transform, demodulation, descrambling, rate matching dematching, and decoding to obtain the restored data. The fronthaul interface settings are related to the data type transmitted through the fronthaul interface; for example, setting it to I... D When using an interface, the data that can be transmitted through that interface is user-scrambled data; when set to II... D When using an interface, the data that can be transmitted through that interface is user-pre-encoded data; when set to I... e When using an interface, the data that can be transmitted through that interface is the demapped data of the resource; when set to I... e2 When using an interface, the data that can be transmitted through that interface is the balanced data.

[0062] To reuse the limited transmission bandwidth resources of a single optical fiber and a single optical module, existing technologies have proposed several data transmission methods based on existing digital distributed base stations. One such method targets a chain-structured digital distributed base station. This method proposes using the Common Public Radio Interface (CPRI) as the fronthaul interface between cascaded Remote Radio Units (RRUs) and between cascaded RRUs and indoor baseband processing units (BBUs), and performs bandwidth combining in the time domain.

[0063] Figure 4 This diagram illustrates a chain-architecture digital distributed base station based on time-domain signal combining, as described in the prior art. Figure 4As shown, during downlink data transmission, the indoor baseband processing unit (BBU) transmits the time-domain signal data to the first-level remote radio unit (RRU 1). RRU 1 copies the time-domain signal data (downlink data copy) for local data processing and forwards the same time-domain signal data to the next-level remote radio unit (RRU 2). This copying and forwarding continues until the same time-domain signal data is transmitted through the air interfaces of all RRU 1-RRU M-1 (not shown), meaning all RRU 1-RRU M-1 units have received the same time-domain signal data. During uplink data transmission, after the time-domain signal data from the next-level remote radio unit is sent to the previous-level remote radio unit, the latter performs saturation addition and other superposition processing on it and its local time-domain signal data, merging them into a single time-domain signal data (uplink data accumulation) before transmitting it to the next higher-level remote radio unit, until it reaches the indoor baseband processing unit (BBU).

[0064] With this technical solution, a single fronthaul interface is reused between cascaded remote radio units (RRUs) and between cascaded RRUs and indoor baseband processing units (BBUs). The bandwidth of the fronthaul interface for air interface data (transmitted through the air interface) is equal to the bandwidth generated by a single RRU, and is independent of the number of RRUs.

[0065] However, this scheme has the following three drawbacks:

[0066] Firstly, during downlink data transmission, all Remote Radio Units (RRUs) in a digital distributed base station transmit the same time-domain signal data. While some RRU signals are superimposed at the user side, resulting in combining gain, the time-domain signals transmitted by the remaining RRUs cause interference and data wastage. Secondly, during uplink data transmission, the RRUs in the digital distributed base station accumulate the time-domain signal data transmitted from their own level and the next-level RRUs. Because this is time-domain signal data, user information cannot be used to distinguish different data from different users, increasing noise and reducing the signal-to-noise ratio, thus affecting service performance. Thirdly, to achieve selective transmission and reception, spatial multiplexing, and distributed Massive MIMO operating modes among RRUs, the Common Public Radio Interface (CPRI) cannot perform bandwidth combining. This, coupled with limited fiber optic and optical module bandwidth, restricts the performance and evolvability of the digital distributed base station.

[0067] Existing technologies also propose another approach for star-shaped digital distributed base stations, which proposes to use the enhanced general public radio interface eCPRI as the fronthaul interface and perform bandwidth combining processing in the frequency domain at the beam level.

[0068] Figure 5 This diagram illustrates a star-shaped digital distributed base station based on frequency domain signal combining, as described in the prior art. Figure 5 As shown, during downlink data transmission, the indoor baseband processing unit (BBU) transmits downlink data to each hub. Each hub copies the downlink data (downlink data copying) and sends it to all remote radio units (RRUs) connected to it. During uplink data transmission, each hub performs frequency domain signal processing on the data of all remote radio units (RRUs) connected to it, and determines the user's association with a subset of remote radio units (RRUs) based on signaling. Then, each hub performs uplink data merging processing on the user's frequency domain data from the aforementioned subset of remote radio units (uplink data merging), such as selective merging or maximum ratio merging, before transmitting it to the indoor baseband processing unit (BBU).

[0069] Although this technical solution can perform bandwidth combining in the frequency domain, it only enables the indoor baseband processing unit (BBU) and the hub to reuse the limited transmission bandwidth resources of a single optical fiber and a single optical module. It does not help the fronthaul interface between the hub and the remote radio unit (RRU). In other words, the hub and the RRU are still in a star topology, and the bandwidth resource reuse effect is not good.

[0070] To address the aforementioned technical problems, this application provides a data transmission method and a data transmission system. The data transmission method of this application enables a chain-structured data transmission system to reuse the limited transmission bandwidth resources of a single optical fiber and a single optical module, thereby reducing data transmission costs and improving data transmission performance.

[0071] Figure 6 This illustrates an exemplary application scenario of the data transmission method according to embodiments of this application.

[0072] like Figure 6 As shown, the data transmission method of this application embodiment can be applied to a data transmission system, which can be set on a digital distributed base station (not shown). The data transmission system executes the data transmission method, which can be used to process downlink data to obtain downlink air interface data and send it to the user equipment through the air interface (antenna); and to receive uplink air interface data from the user equipment through the air interface (antenna) and process it to obtain uplink data.

[0073] Figure 7 A schematic diagram illustrating the structure of a data transmission system according to an embodiment of this application is shown. Figure 7 As shown, in one possible implementation, the data transmission system includes a first processing unit 70 and multiple second processing units 71-7M (M≥2 and integers) cascaded via a single optical fiber. The enhanced general public radio interface (eCPRI) is used between the first processing unit 70 and the next-level second processing unit 71, and between adjacent levels of second processing units. In this case, the data transmission system can be a chain-architecture data transmission system. The first processing unit 70 can be the indoor baseband processing unit (BBU) described above, and the second processing units 71-7M can be the radio remote unit (RRU) described above. Since the first processing unit 70 can be the first stage of the cascade, the multiple second processing units 71-7M are all subsequent stages of the first processing unit. An optical module can be installed on each of the first processing unit 70 and the multiple second processing units 71-7M, with both ends of the optical fiber connected to the optical module. The optical fiber can be used to transmit downlink and uplink data, where data output from the previous stage to the next stage can be downlink data, and data output from the next stage to the previous stage can be uplink data.

[0074] Each second processing unit also includes an antenna, which can output data (i.e., downlink air interface data) to user equipment in the application scenario, or receive data (i.e., uplink air interface data) from user equipment in the application scenario. Downlink air interface data can be obtained through downlink data processing, and uplink air interface data can be used to process and obtain uplink data. For specific implementation details, please refer to the following text and... Figure 8 and Figure 9 Related descriptions.

[0075] The following describes how the data transmission method according to the embodiments of this application realizes the transmission of downlink data and uplink data.

[0076] Figure 8 The diagram illustrates a flow chart of a data transmission method according to an embodiment of this application, specifically for downlink data transmission.

[0077] like Figure 8 As shown, in one possible implementation, this application proposes a data transmission method applied to a data transmission system. The data transmission system includes a first processing unit and multiple second processing units cascaded via a single optical fiber. The first processing unit and the next-level second processing unit, as well as adjacent second processing units, utilize an enhanced general public radio interface (eCPRI). The method includes steps S81-S84:

[0078] In step S81, the first processing unit generates a first shaping weight corresponding to each of the plurality of second processing units, and sends downlink data, first user information related to the plurality of second processing units, and the first shaping weight to the next level second processing unit.

[0079] Beamforming weights are parameters used in the beamforming process. The first processing unit can treat all antennas of the second processing unit within the cell as a whole and generate a first beamforming weight based on this. The first beamforming weight indicates the mapping relationship between the data from the flow domain to the beam domain when the second processing unit processes downlink data. An exemplary method for generating the first beamforming weight can be found in the further description of step S81 below. First user information is used to indicate whether a user is associated with each second processing unit and to indicate how each second processing unit processes downlink data.

[0080] Downlink data can be obtained by processing the raw data to be sent as instructed by the user, and the downlink data can be sent to each second processing unit via multicast. The fronthaul interface can be pre-configured according to the application scenario requirements, and this application does not impose any restrictions on it. Multicast is implemented by each cascaded level sequentially sending downlink data to the next level. In step S81, the first processing unit, as the first level of the cascade, can first send downlink data to the second processing unit of the next level. The first shaping weight and the first user information do not necessarily need to be multicast; the first processing unit can first send the first user information and the first shaping weight related to multiple second processing units to the second processing unit of the next level.

[0081] Step S82: For each second processing unit, the second processing unit sends the downlink data, as well as the first user information and the first shaping weight related to the second processing unit from the next level to the last level.

[0082] Each second processing unit sequentially sends downlink data to the next-level second processing unit until the downlink data is sent to the last-level second processing unit, at which point the multicast of downlink data can be considered complete. Each level of second processing unit only needs to send the first user information and the first shaping weight related to the next-level to the last-level second processing unit. Therefore, the first user information and the first shaping weight sent by each level of second processing unit to the next-level second processing unit may be different. In this case, the first user information and the first shaping weight received by each level of second processing unit must include the first user information and the first shaping weight related to itself, which can reduce the data transmission cost between any two second processing units. For the last-level second processing unit, since there is no next-level second processing unit, it is not necessary to send downlink data, the first user information, and the first shaping weight to other second processing units.

[0083] When downlink data, first user information, and first beamforming weights are transmitted between cascaded stages, they can be transmitted based on a pre-configured fronthaul interface. The fronthaul interface can be an enhanced general public radio interface (GPRS), examples of which can be found above. Figure 3 Regarding the relevant descriptions, this application does not restrict the specific selection method of the fronthaul interface.

[0084] Step S83: For each second processing unit, when the first user information and the first shaping weight received by the second processing unit include first user information and first shaping weight related to itself, the received downlink data is processed according to the first user information and the first shaping weight related to itself to obtain downlink air interface data.

[0085] The first user information and the first beamforming weight associated with each second processing unit can be used when that second processing unit processes downlink data. Processing the downlink data may include beamforming, etc., and examples of this can be found in the further description of step S83 below. Downlink air interface data is obtained after downlink data processing.

[0086] Step S84: For each second processing unit, when the second processing unit obtains the downlink air interface data, it sends the downlink air interface data to the user equipment through the air interface.

[0087] According to the data transmission method of this application embodiment, a first processing unit generates first shaping weights corresponding one-to-one with a plurality of second processing units, and sends downlink data, first user information related to the plurality of second processing units, and first shaping weights to the next-level second processing unit, so that the next-level second processing unit can obtain the downlink data to be processed and the first user information and first shaping weights to be used when processing the downlink data; by each second processing unit sending downlink data, as well as the first user information and first shaping weights related to the next-to-last level second processing unit, each second processing unit can obtain downlink data and the first user information and first shaping weights related to itself, and the amount of data transmitted over the optical fiber is reduced; by including the first user information and first shaping weights related to itself in the first user information and first shaping weights received by each second processing unit, the received downlink data is processed according to the first user information and first shaping weights related to itself to obtain downlink air interface data, so that the downlink data processing work can be completed, and the downlink air interface data can be sent to the user equipment through the air interface, thereby completing the transmission of downlink data. In the data transmission system employing this method, a first processing unit and multiple second processing units are cascaded via a single optical fiber, thus enabling a chain-like architecture. Since an enhanced universal public radio interface (GPRS) is used between the first processing unit and the next-level second processing unit, and between adjacent levels of second processing units, this enhanced GPRS allows each second processing unit to process downlink data based on first user information and a first shaping weight. This enables selective processing of downlink data, unlike existing GPRS interfaces which cannot utilize the first user information and first shaping weight at the second processing unit level. In other words, each second processing unit can distinguish different data from different users based on the first user information and the first shaping weight, reducing noise and improving the signal-to-noise ratio. In this context, the data transmission method according to the embodiments of this application allows the chain-like data transmission system to reuse the limited transmission bandwidth resources of a single optical fiber and a single optical module, thereby reducing data transmission costs and improving data transmission performance.

[0088] In one possible implementation, the first user information includes information indicating whether the user is associated with each second processing unit, and indicating the processing method (e.g., modulation, layer mapping) of each second processing unit for downlink data. Therefore, using the first shaping weight and the first user information, it is possible to determine whether a user is associated with a particular second processing unit, enabling the associated second processing unit to process downlink data. In this case, the first shaping weight does not need to be refreshed. The first shaping weight determines how the downlink air interface data obtained by the second processing unit based on the downlink data is coordinated with the downlink air interface data obtained by other second processing units. An exemplary use of the first shaping weight can be found in the further description of step S83 below. The downlink data is obtained by processing the original data sent according to the user's instructions; therefore, the downlink data is inherently associated with the user. Furthermore, the first shaping weight also corresponds one-to-one with the second processing unit, and the first user information is necessarily associated with the user. That is, the first shaping weight, the first user information, and the downlink data have a correlation relationship, and this correlation relationship is with the user.

[0089] In this way, it is possible to determine whether a user is related to a certain second processing unit based on the first user information, without refreshing the first shaping weight.

[0090] In one possible implementation, the first shaping weight includes information indicating whether the user is associated with each second processing unit, and step S81 includes:

[0091] Determine the downlink operating mode of the data transmission system based on the configuration information;

[0092] Determine whether the user is related to each second processing unit;

[0093] For each second processing unit associated with the user, a first shaping weight corresponding to that second processing unit is generated for the user according to the determined downlink operating mode.

[0094] For example, the first processing unit can first determine the downlink operating mode of the data transmission system based on the configuration information. This configuration information can come from the network management device and can indicate the downlink operating mode of the data transmission system. The downlink operating modes of the data transmission system may include cell merging, selective transmit / receive, spatial division multiplexing, and distributed Massive MIMO, etc. The generation method of the first beamforming weight may differ under each downlink operating mode. Examples of the generation methods of the first beamforming weight under each downlink operating mode can be found in the relevant descriptions in the different downlink operating mode sections below.

[0095] A user is associated with multiple second processing units. For example, if a user is associated with a certain second processing unit, then that second processing unit is considered to need to process the downlink data obtained from the raw data sent according to the user's instructions. Conversely, if a user is not associated with a certain second processing unit, then that second processing unit is considered not to need to process the downlink data obtained from the raw data sent according to the user's instructions. The first beamforming weight can be configured to include information indicating whether the user is associated with each second processing unit, in addition to indicating the mapping relationship from the flow domain to the beam domain when the second processing unit processes the downlink data. In this case, the first user information may not include information indicating whether the user is associated with each second processing unit. Therefore, the first beamforming weight can be used to determine whether a user is associated with a particular second processing unit. The first beamforming weight and the first user information enable the associated second processing unit to process the downlink data, at which point the first beamforming weight can be refreshed. Therefore, the first processing unit can determine whether a user is related to each of the second processing units. If it is determined that the user is related to a certain second processing unit, then a first shaping weight corresponding to that second processing unit needs to be generated for the user. If it is determined that the user is not related to a certain second processing unit, then it is not necessary to generate a first shaping weight corresponding to that second processing unit for the user, or the first shaping weight related to that second processing unit can be set to zero. The first shaping weight set to zero can also be not sent to reduce data transmission costs.

[0096] In this way, it is possible to determine whether a user is related to a certain second processing unit simply by using the first shaping weight, and to refresh the first shaping weight in a timely manner.

[0097] In one possible implementation, step S83 includes:

[0098] When the first user information or the first shaping weight associated with itself indicates that the user is associated with itself, the first shaping weight associated with itself is used to convert the downlink data from the flow domain to the beam domain to obtain the downlink baseband data in the beam domain. The downlink air interface data is radio frequency data converted from the downlink baseband data.

[0099] For example, the second processing unit can obtain downlink data, its own associated first user information, and its own associated (corresponding) first beamforming weights through the fronthaul interface (enhanced Common Radio Interface eCPRI). Provided the bandwidth of the fronthaul interface (enhanced Common Radio Interface eCPRI) is acceptable, various downlink operating modes such as cell merging, selective transmit / receive, spatial multiplexing, and distributed Massive MIMO can be implemented on a chain-architecture digital distributed base station. Exemplarily, each second processing unit can determine whether a user is associated with it based on its own associated first user information or first beamforming weights. When a user is determined to be associated, the downlink data is processed according to the processing method indicated by the first user information (e.g., modulation, layer mapping, etc.). During processing, this may include using the associated (corresponding) first beamforming weights to convert the downlink data from the flow domain to the beam domain, thereby completing beamforming. Then, after processing using existing technologies (e.g., inverse fast Fourier transform), downlink baseband data in the beam domain is obtained. This downlink baseband data in the beam domain corresponds to each antenna of the second processing unit. Downlink air interface data can be radio frequency (RF) data converted from downlink baseband data. RF data can be transmitted using an antenna, i.e., sent to user equipment via the air interface. The conversion from the flow domain to the beam domain using the first shaping weight, and the conversion from downlink baseband data in the beam domain to RF data in the antenna domain, can both be implemented by the second processing unit based on existing technology; the specific conversion methods will not be described here.

[0100] Those skilled in the art should understand that the above description focuses on the differences in the processing flow of downlink data to obtain air interface data between the embodiments of this application and the prior art (the difference lies in the specific implementation method of the conversion from watershed to beam domain). Apart from the differences described above, other processing methods for downlink data can be the same as those in the prior art. For example, before performing the conversion from watershed to beam domain, the following methods can be used: Figure 3 The coding, rate matching, scrambling, modulation, layer mapping, precoding, and resource mapping shown can be used in one or more of the following processing methods after the conversion from the line domain to the beam domain: inverse fast Fourier transform and insertion of cyclic prefix. This application does not limit the specific processing flow for processing downlink data to obtain air interface data.

[0101] In this way, the conversion from downlink data to downlink air interface data can be completed. The converted downlink air interface data can then be sent to the user equipment via the air interface, thus completing the downlink transmission of downlink data.

[0102] The following sections describe the various downlink operating modes of the data transmission system.

[0103] In one possible implementation, the downlink operating mode of the data transmission system includes cell merging mode.

[0104] In the cell merging mode, each second processing unit processes the downlink data, and the first shaping weight corresponding to each second processing unit is the same. Each second processing unit sends the downlink air interface data to the user equipment through the air interface.

[0105] The maximum number of beam domains is equal to the number of antennas in the plurality of second processing units.

[0106] For example, the purpose of cell merging can be to merge multiple physical cells into one logical cell. Corresponding to the data transmission system of this application embodiment, when transmitting downlink data, cell merging can be achieved by each second processing unit performing the same processing on the downlink data (corresponding to the user). Therefore, in step S81, when generating the first beamforming weight, the same first beamforming weight can be generated for each second processing unit for the same user. Since each second processing unit participates in the downlink data processing, it also obtains downlink air interface data, and each second processing unit can send downlink air interface data to the user equipment through the air interface. During the downlink data processing, when converting data from the flow domain to the beam domain and performing beamforming using the first beamforming weight, the maximum number of beam domains can be the number of antennas of multiple second processing units. The specific value can be determined by the first processing unit.

[0107] In this way, the data transmission method of this application embodiment can achieve the effect of cell merging.

[0108] In one possible implementation, the downlink operating mode of the data transmission system includes selecting a transmit / receive mode.

[0109] In the selected transmit / receive mode, at least one second processing unit processes the downlink data. The air interface used by the at least one second processing unit is not allowed to be used by other users other than the user in other second processing units. The at least one second processing unit sends the downlink air interface data to the user equipment through the air interface.

[0110] The maximum number of beam domains is equal to the number of antennas in the plurality of second processing units.

[0111] For example, the purpose of selective transmission and reception can be to improve performance by selecting one or more second processing units already used by a user for data transmission. The first processing unit can first determine that a user can use the air interface resources of at least one second processing unit, and that the air interface resources used are not reused by other users besides that user in other second processing units (i.e., at least one second processing unit processes the downlink data, and the air interface used by that at least one second processing unit is not allowed to be used by other users besides that user in other second processing units). Then, the downlink data of that user can be processed by that at least one second processing unit, thus reducing the data processing cost for other second processing units to process the downlink data, thereby achieving selective transmission and reception. In this case, when generating the first beamforming weight in step S81, the first beamforming weight generated for each second processing unit for the same user is not necessarily the same, but the maximum number of beam domains can still be the number of antennas of multiple second processing units. Its specific value can be determined by the first processing unit.

[0112] In this way, the data transmission method of this application embodiment can achieve the effect of selective sending and receiving, thereby improving the flexibility and performance of the data transmission method.

[0113] In one possible implementation, the downlink operating mode of the data transmission system includes a spatial multiplexing mode.

[0114] In the spatial multiplexing mode, at least one second processing unit processes the downlink data. The air interface used by the at least one second processing unit is allowed to be used by other users besides the user in other second processing units. The at least one second processing unit sends the downlink air interface data to the user equipment through the air interface.

[0115] The maximum number of beam domains is the product of the number of antennas of the plurality of second processing units and the preset spatial multiplexing coefficient.

[0116] For example, the purpose of spatial division multiplexing is to further gain the advantage of multiple users sharing the same second processing unit, based on the selection of transmit and receive. The first processing unit can first determine that a user can use a portion of the air interface resources of the second processing unit, and the used air interface resources can be reused by other users besides that user in other second processing units (i.e., at least one second processing unit processes the downlink data, and the air interface used by this at least one second processing unit is allowed to be used by other users besides that user in other second processing units), as long as different users use the air interface resources of their respective second processing units. In the spatial division multiplexing operating mode, the first processing unit can also pre-determine a spatial division multiplexing coefficient. In this case, the maximum number of beam domains can be the product of the number of antennas of multiple second processing units and the spatial division multiplexing coefficient, the specific value of which can be determined by the first processing unit. Furthermore, as the downlink service requirements in the application scenario change, the spatial multiplexing coefficient and the number of second processing units to which the air interface resources available to a user belong can also be adjusted accordingly. Therefore, the maximum number of beam domains can evolve with changes in the application scenario, making it more adaptable to different application scenarios and user needs, thus improving data transmission performance.

[0117] In this way, the data transmission method of this application embodiment can achieve the effect of spatial multiplexing, thereby improving the flexibility and performance of the data transmission method.

[0118] In one possible implementation, the downlink operating mode of the data transmission system includes a distributed massive MIMO mode.

[0119] In the distributed massive MIMO mode, at least one second processing unit processes the downlink data, and the first processing unit generates a first shaping weight corresponding to the at least one second processing unit for each beam domain.

[0120] The maximum number of beam domains is associated with the total number of antennas of the plurality of second processing units.

[0121] For example, the purpose of Distributed Massive MIMO (DMMO) is to further enhance data transmission performance based on spatial multiplexing by utilizing time synchronization and phase alignment. The first processing unit can treat a second processing unit (i.e., at least one second processing unit) within the same cell as a single DMMO array, and calibrate the time delay, phase, and amplitude of the antennas of the second processing unit using existing antenna correction methods to construct a DMMO environment. This process can be identical to existing methods for implementing DMMO. Then, the data transmission system can generate first shaping weights for the second processing unit within the same cell based on each beam domain. The maximum number of beam domains is theoretically related to the cumulative number of antennas (total number of antennas) of the second processing unit, and its specific value can be determined by the first processing unit. Furthermore, as downlink service requirements change in the application scenario, the maximum number of beam domains can change accordingly, exhibiting evolvability. Therefore, it is more adaptable to different application scenarios and user needs, resulting in improved data transmission performance.

[0122] In this way, the data transmission method of this application embodiment can achieve the effect of a distributed large-scale antenna array, improving the flexibility and performance of the data transmission method.

[0123] Figure 9 The diagram illustrates a flow chart of a data transmission method according to an embodiment of this application, specifically for uplink data transmission.

[0124] like Figure 9 As shown, in one possible implementation, this application proposes a data transmission method applied to a data transmission system. The data transmission system includes a first processing unit and multiple second processing units cascaded via a single optical fiber. An enhanced general-purpose wireless interface is used between the first processing unit and the next-level second processing unit, and between adjacent levels of second processing units. The method includes steps S91-S94:

[0125] In step S91, the first processing unit generates a second shaping weight corresponding to each of the plurality of second processing units, and sends the second user information and the second shaping weight related to the plurality of second processing units to the next level second processing unit.

[0126] The first processing unit can treat all antennas of the second processing unit within the cell as a whole and generate a second shaping weight based on this. An exemplary method for generating the second shaping weight can be found in the relevant description below. The second shaping weight is used to indicate the mapping relationship between the data from the beam domain to the flow domain when the second processing unit processes uplink air interface data. The second user information is used to indicate whether the user is associated with each second processing unit and to indicate the processing method of each second processing unit for uplink air interface data. In step S91, the first processing unit, as the first level of the cascade, can first send the second user information and the second shaping weight to the second processing unit at the next level.

[0127] Step S92: For each second processing unit, the second processing unit sends the second user information and the second shaping weight related to the next-level second processing unit to the last level of the second processing unit.

[0128] Each level of the second processing unit only needs to send the second user information and second shaping weights related to the next level up to the last level of the second processing unit. Therefore, the second user information and second shaping weights sent by each level of the second processing unit to the next level of the second processing unit may be different. In this case, the second user information and second shaping weights received by each level of the second processing unit will necessarily include the second user information and second shaping weights related to itself, and this can reduce the data transmission cost between the second processing units. For the last level of the second processing unit, since there are no next level of the second processing unit, it is not necessary to send the second user information and second shaping weights to other second processing units.

[0129] Step S93: For each second processing unit, when the second processing unit does not receive uplink data, the second processing unit processes the received uplink air interface data and the second user information and the second shaping weight related to itself to obtain uplink data. When the second processing unit receives uplink data, the second processing unit processes the received uplink air interface data, the uplink data and the second user information and the second shaping weight related to itself to obtain new uplink data.

[0130] The second user information and second shaping weight associated with each second processing unit can be used when the second processing unit processes the uplink data. The second processing unit can receive uplink air interface data from the user equipment through the air interface (i.e., antenna). For a certain second processing unit, the uplink data can be obtained by processing the uplink air interface data it receives (and the uplink data from the next-level second processing unit) and the second user information and second shaping weight associated with itself. The processing may include converting beam domain data to water domain data, etc. For an example, please refer to the further description of step S93 below.

[0131] Step S94: For each second processing unit, the second processing unit sends the processed uplink data to the next higher level second processing unit or the previous higher level first processing unit.

[0132] When uplink data, second user information, and second beamforming weights are transmitted between cascaded stages, they can be transmitted based on a pre-configured fronthaul interface. The fronthaul interface can be an enhanced general public wireless interface (GPWAN), examples of which can be found above. Figure 3 Regarding the relevant descriptions, this application does not restrict the specific selection method of the fronthaul interface.

[0133] According to the data transmission method of this application embodiment, a first processing unit generates second shaping weights corresponding one-to-one with a plurality of second processing units, and sends second user information and second shaping weights related to the plurality of second processing units to the next-level second processing unit, so that the next-level second processing unit of the first processing unit can obtain the second user information and second shaping weights needed when processing uplink data; by each second processing unit sending the second user information and second shaping weights related to the next-level to the last-level second processing unit to the next-level second processing unit, each second processing unit can obtain the second user information and second shaping weights related to itself, and the amount of data transmitted over the optical fiber is reduced; for each second processing unit, when the second processing unit does not receive When uplink data arrives, the second processing unit processes the received uplink air interface data and its associated second user information and second shaping weights to obtain uplink data. Upon receiving uplink data, the second processing unit processes the received uplink air interface data, the uplink data, its associated second user information, and the second shaping weights to obtain new uplink data, thus completing the uplink data processing. The second processing unit then sends the processed uplink data to the next-level second processing unit or the previous-level first processing unit to complete the uplink data transmission. The uplink data output by each second processing unit is the merged uplink data output by the next-level to the last-level second processing unit, which reduces the amount of data transmitted over the optical fiber. In the data transmission system employing this method, a first processing unit and multiple second processing units are cascaded via a single optical fiber, thus enabling a chain-like architecture. Since an enhanced universal public wireless interface (GPWI) is used between the first processing unit and the next-level second processing unit, and between adjacent levels of second processing units, this enhanced GPWI allows each second processing unit to process uplink data based on second user information and second shaping weights. This allows the data transmission system to selectively process uplink data, unlike existing GPWIs which cannot utilize second user information and second shaping weights for processing at the second processing unit level. In other words, each second processing unit can distinguish different data from different users based on second user information and second shaping weights, reducing noise and improving the signal-to-noise ratio. In this context, the data transmission method according to the embodiments of this application enables the chain-like data transmission system to reuse the limited transmission bandwidth resources of a single optical fiber and a single optical module, thereby reducing data transmission costs and improving data transmission performance.

[0134] In one possible implementation, the second user information includes information indicating whether the user is associated with each second processing unit, and indicating the processing method (e.g., demodulation, descrambling, etc.) of each second processing unit for uplink air interface data. Therefore, by using the second shaping weight and the second user information, it can be determined whether the user is associated with a certain second processing unit, and the associated second processing unit can process the uplink air interface data. In this case, the second shaping weight does not need to be refreshed. The second shaping weight determines how the uplink data obtained by the second processing unit based on the uplink air interface data is coordinated with the uplink data obtained by other second processing units. An exemplary use of the second shaping weight can be found in the further description of step S93 below. Uplink air interface data includes data from the user equipment; therefore, the uplink air interface data is inherently associated with the user. Furthermore, the second shaping weight is also associated with the second processing unit, and the second user information is necessarily associated with the user. That is, the second shaping weight, the second user information, and the uplink air interface data have a correlation relationship, and the correlation relationship is with the user.

[0135] In this way, it can be determined whether the user is related to a certain second processing unit through the second user information, and the second shaping weight can be refreshed without refreshing it.

[0136] In one possible implementation, the second shaping weight includes information indicating whether the user is associated with each second processing unit, and step S91 includes:

[0137] Determine the uplink operating mode of the data transmission system based on the configuration information;

[0138] Determine whether the user is related to each second processing unit;

[0139] For each second processing unit associated with the user, a second shaping weight corresponding to that second processing unit is generated for the user according to the determined uplink operating mode.

[0140] For example, the second shaping weights can include information indicating whether a user is associated with each second processing unit, in addition to indicating the mapping relationship between the data from the beam domain to the flow domain when the second processing unit processes uplink air interface data. In this case, the second user information may not include information indicating whether a user is associated with each second processing unit. Therefore, the second shaping weights can clearly determine whether a user is associated with a particular second processing unit. The second shaping weights and the second user information enable the associated second processing unit to process the uplink air interface data, at which point the second shaping weights can be refreshed. In this case, the generation method of the second shaping weights can be found in the description of the generation method of the first shaping weights above, and will not be repeated here.

[0141] In this way, it is possible to determine whether a user is associated with a certain second processing unit simply by using the second shaping weight, and to refresh the second shaping weight in a timely manner.

[0142] In one possible implementation, step S93 includes:

[0143] When the second user information or the second shaping weight indicates that the user is related to itself, the second processing unit converts the uplink air interface data into uplink baseband data in the beam domain, and uses the second shaping weight related to itself to convert the uplink baseband data from the beam domain to the water domain to obtain the enhanced general public radio interface data of the water domain.

[0144] When the second processing unit does not receive uplink data, the enhanced general public radio interface data is used as the uplink data;

[0145] When the second processing unit receives uplink data, it merges the received uplink data with the enhanced general public radio interface data, and uses the merged data as the new uplink data.

[0146] For example, the second processing unit can obtain its own second user information and its own second beamforming weights through the fronthaul interface (enhanced Common Radio Interface eCPRI). Provided the bandwidth of the fronthaul interface (eCPRI) is acceptable, various uplink operating modes such as cell merging, selective transmit / receive, spatial multiplexing, and distributed Massive MIMO can be implemented on a chain-architecture digital distributed base station. For instance, uplink air interface data may include radio frequency (RF) data, which can be received using an antenna, i.e., receiving uplink air interface data from the user equipment through the air interface. Each second processing unit can determine whether a user is related to itself based on the second user information or the second shaping weight associated with itself. When indicating that a user is related to itself, it processes the uplink air interface data according to the processing method (such as demodulation, descrambling, etc.) indicated by the second user information. During the processing, it may include converting the radio frequency data included in the uplink air interface data into uplink baseband data in the beam domain. The uplink baseband data in the beam domain corresponds to each antenna of the second processing unit. Then, it uses the second shaping weight associated with itself to convert the uplink baseband data from the beam domain to the flow domain, thereby obtaining the enhanced general public radio interface data of the flow domain. If the second processing unit is the last level of the second processing unit, it will not receive uplink data. Therefore, it can use the enhanced general public radio interface (GPRS) data as uplink data and send it to the next level of the second processing unit. If the second processing unit has a subsequent level of the second processing unit, it will receive uplink data from the next level of the second processing unit. The second processing unit can merge the received uplink data with the enhanced GPRS data it has received, and use the merged data as new uplink data to send to the next level of the second processing unit or the previous level of the first processing unit.

[0147] The conversion of data from the beam domain to the flow domain using the second shaping weight, and the conversion of radio frequency data in the antenna domain to uplink baseband data in the beam domain, can both be implemented by the second processing unit based on existing technologies. The specific conversion methods will not be described here.

[0148] Those skilled in the art should understand that the above description focuses on the differences in the processing flow of enhanced general public radio interface data compared to the prior art in the embodiments of this application (the difference lies in the specific implementation method of beam domain to flow domain conversion). Apart from the differences described above, other processing methods for air interface data can be the same as those in the prior art. For example, before performing beam domain to flow domain conversion, the following methods can be used: Figure 3The processing methods shown include removing the cyclic prefix and fast Fourier transform. After the conversion from the traveling beam domain to the flow domain, one or more of the following processing methods can be used: resource demapping, channel estimation, combining, equalization, (inverse Fourier transform), demodulation, descrambling, derate matching, and decoding. This application does not limit the specific processing flow for processing air interface data to obtain uplink data.

[0149] In this way, the conversion from uplink air interface data to uplink data can be completed. The converted uplink data can then be sent to the cascaded upstream stage via the air interface, thus completing the uplink transmission of the uplink data.

[0150] In one possible implementation, the merging process of the received uplink data and the enhanced general public radio interface data includes:

[0151] The received uplink data and the enhanced general public radio interface data processed by itself are combined with the data corresponding to the same user, which are obtained by processing uplink baseband data in the same beam domain and uplink air interface data in the same frequency domain.

[0152] The received uplink data and the enhanced general public radio interface data obtained through its own processing are merged to identify data from the same user, the same flow domain, and the same bit.

[0153] For example, for a certain second processing unit, the enhanced general public radio interface (GPAN) data it processes may have different metrics than the received uplink data, thus making direct merging impossible. In this case, the received uplink data can first be restored to the same scaling dimension as the local GPAN data. Then, the data corresponding to the same user, processed from uplink baseband data in the same beam domain and uplink air interface data in the same frequency domain, can be proportionally merged (e.g., added), or the data corresponding to the same user, in the same flow domain and with the same bits can be proportionally merged (e.g., added). Here, "same bits" can refer to the same soft bits. The amount of data after merging is reduced compared to before merging, thus reducing data transmission costs.

[0154] In this way, data can be merged to obtain upstream data with lower redundancy.

[0155] The following sections describe the various uplink operating modes of the data transmission system.

[0156] In one possible implementation, the uplink operating mode of the data transmission system includes a cell merging mode.

[0157] In the cell merging mode, each second processing unit processes the uplink air interface data, and the second shaping weights corresponding to each second processing unit are the same. Each second processing unit receives the uplink air interface data from the user equipment through the air interface.

[0158] The maximum number of beam domains is equal to the number of antennas in the plurality of second processing units.

[0159] For example, the purpose of cell merging can be to merge multiple physical cells into one logical cell. Corresponding to the data transmission system of this application embodiment, when transmitting uplink data, cell merging can be achieved by each second processing unit performing the same processing on the uplink air interface data corresponding to the user. Therefore, in step S91, when generating the second shaping weight, the same second shaping weight can be generated for each second processing unit for the same user. Since each second processing unit participates in the processing of uplink air interface data, each second processing unit receives uplink air interface data from the user equipment through the air interface, thus obtaining uplink data and sending it to the next-level second processing unit. During the processing of uplink air interface data, when using the second shaping weight to convert data from the beam domain to the flow domain, the maximum number of beam domains can be the number of antennas of multiple second processing units. Its specific value can be determined by the first processing unit.

[0160] In this way, the data transmission method of this application embodiment can achieve the effect of cell merging.

[0161] In one possible implementation, the uplink operating mode of the data transmission system includes selecting a transmit / receive mode.

[0162] In the selected transmit / receive mode, at least one second processing unit processes the uplink air interface data. The air interface used by the at least one second processing unit is not allowed to be used by other users other than the user in other second processing units. The at least one second processing unit receives the uplink air interface data from the user equipment through the air interface.

[0163] The maximum number of beam domains is equal to the number of antennas in the plurality of second processing units.

[0164] For example, the purpose of selective transmission and reception can be to improve performance by selecting one or more second processing units already used by a user for data transmission. The first processing unit can first determine that a user can use the air interface resources of at least one second processing unit, and that the air interface resources used are not reused by other users besides that user in other second processing units (i.e., at least one second processing unit processes the uplink air interface data, and the air interface used by that at least one second processing unit is not allowed to be used by other users besides that user in other second processing units). Then, the uplink air interface data of that user can be processed by that at least one second processing unit, thus reducing the data processing cost for other second processing units to process the uplink air interface data, thereby achieving selective transmission and reception. In this case, in step S91, when generating the second shaping weights, the second shaping weights generated for at least one second processing unit for the same user are not necessarily the same, but the maximum number of beam domains can still be the number of antennas of multiple second processing units. The specific value can be determined by the first processing unit.

[0165] In this way, the data transmission method of this application embodiment can achieve the effect of selective sending and receiving, thereby improving the flexibility and performance of the data transmission method.

[0166] In one possible implementation, the uplink operating mode of the data transmission system includes a spatial multiplexing mode.

[0167] In the spatial multiplexing mode, at least one second processing unit processes the uplink air interface data. The air interface used by the at least one second processing unit is allowed to be used by other users besides the user in other second processing units. The at least one second processing unit receives the uplink air interface data from the user equipment through the air interface.

[0168] The maximum number of beam domains is the product of the number of antennas of the plurality of second processing units and the preset spatial multiplexing coefficient.

[0169] For example, the purpose of spatial division multiplexing is to further gain the advantage of multiple users sharing the same second processing unit, based on the selection of transmit and receive. The first processing unit can first determine that a user can use the air interface resources of at least one second processing unit, and that the used air interface resources can be multiplexed by other users besides that user in other second processing units (i.e., at least one second processing unit processes the uplink air interface data, and the air interface used by this at least one second processing unit is allowed to be used by other users besides that user in other second processing units), as long as different users use the air interface resources of their respective related second processing units. In the spatial division multiplexing operating mode, the first processing unit can also predetermine a spatial division multiplexing coefficient. In this case, the maximum number of beam domains can be the product of the number of antennas of multiple second processing units and the spatial division multiplexing coefficient, the specific value of which can be determined by the first processing unit. Furthermore, as the uplink service requirements in the application scenario change, the spatial multiplexing coefficient and the number of at least one second processing unit to which a user's available air interface resources belong can also be adjusted accordingly. Therefore, the maximum number of beam domains can evolve with the application scenario, making it more adaptable to different application scenarios and user needs, thus improving data transmission performance.

[0170] In this way, the data transmission method of this application embodiment can achieve the effect of spatial multiplexing, thereby improving the flexibility and performance of the data transmission method.

[0171] In one possible implementation, the uplink operating mode of the data transmission system includes a distributed massive MIMO mode.

[0172] In the distributed massive MIMO mode, at least one second processing unit processes the uplink air interface data, and the first processing unit generates a second shaping weight corresponding to at least one second processing unit for each beam domain.

[0173] The maximum number of beam domains is associated with the total number of antennas of the plurality of second processing units.

[0174] For example, the purpose of Distributed Massive MIMO (DMMO) is to further enhance data transmission performance based on spatial multiplexing by utilizing time synchronization and phase alignment. The first processing unit can treat the second processing units (i.e., at least one second processing unit) within the same cell as a single DMMO array, and calibrate the time delay, phase, and amplitude of the antennas of the second processing units using existing antenna correction methods to construct a DMMO environment. This process can be identical to existing methods for implementing DMMO. Then, the data transmission system can generate second beamforming weights for the second processing units within the same cell based on each beam domain. The maximum number of beam domains is theoretically related to the cumulative number of antennas (total number of antennas) of the multiple second processing units, and its specific value can be determined by the first processing unit. Furthermore, as uplink service requirements change in the application scenario, the maximum number of beam domains can change accordingly, exhibiting evolvability. Therefore, it is more adaptable to different application scenarios and user needs, resulting in improved data transmission performance.

[0175] In this way, the data transmission method of this application embodiment can achieve the effect of a distributed large-scale antenna array, improving the flexibility and performance of the data transmission method.

[0176] Those skilled in the art should understand that, Figure 8 In the data transmission method shown, the first user information can also instruct each second processing unit on how to process the uplink air interface data, and the first shaping weight can also instruct the second processing unit on the mapping relationship between the data from the beam domain to the flow domain when processing the uplink air interface data. In this case, if the data transmission system has first performed downlink data transmission and executed steps S81 and S82, then the uplink data transmission method has actually been completed (see...). Figure 9 Steps S91 and S92 in the data transmission system are used in the subsequent data transmission method for uplink data transmission (see step S91 and S92). Figure 9 When the first user information and the first beamforming weights are used as the second user information and the second beamforming weights, steps S93 and S94 can be executed without further execution of steps S91 and S92. Similarly, the second user information can also indicate the processing method of each second processing unit for downlink data, and the second beamforming weights can also indicate the mapping relationship of data from the flow domain to the beam domain when the second processing unit processes downlink data. In this case, if the data transmission system has first performed uplink data transmission and executed steps S91 and S92, then the downlink data transmission has actually been completed (see...). Figure 8 The partial work in steps S81 and S82 of the data transmission system is therefore performed subsequently in the data transmission method for downlink data transmission (see [link]). Figure 8 In steps S81 and S82, only downlink data is transmitted. The second user information and the second shaping weight are directly used as the first user information and the first shaping weight, and then step S83 is executed. This method simplifies the workflow of the data transmission system.

[0177] The following is an example of data transmission according to the data transmission method of the present application.

[0178] For example, the downlink cutoff point of the Enhanced Common Radio Interface (eCPRI) can be pre-configured to I. D Interface, uplink split point is I e Interface (see) Figure 3 The following sections, divided into downlink data processing and uplink data processing, describe exemplary methods for data transmission according to the data transmission method of this application.

[0179] In this example, the downlink data transmission method according to the embodiment of this application involves the following process:

[0180] (1) The first processing unit generates a first shaping weight corresponding to each of the multiple second processing units, and clarifies that all users use the same processing in each second processing unit, and generates the same first shaping weight for each second processing unit.

[0181] (2) The first processing unit uses existing technologies for encoding, rate matching, and scrambling processing of the downlink data (see...). Figure 3 The scrambled downlink data is obtained and then processed through I... D The interface sends the scrambled downlink data, first user information, and first beamforming weights to multiple second processing units. The scrambled downlink data is multicast to all second processing units within the cell. The implementation of multicast can be found in the relevant description above. The first user information specifies how all second processing units should process the scrambled downlink data. Steps (1) and (2) correspond to step S81 above.

[0182] (3) The second processing unit accesses the fronthaul interface (I) D The interface obtains information related to itself, including the user's scrambled downlink data, the first user information related to itself and the last-level second processing unit, and the first shaping weight related to itself and the last-level second processing unit, wherein the user's scrambled downlink data comes from the multicast of the first processing unit.

[0183] (4) The second processing unit forwards the scrambled downlink data of the user, as well as the first user information related to the second processing unit from the next level to the last level and the first shaping weight related to the second processing unit from the next level to the last level (one-to-one correspondence), wherein the scrambled downlink data of the user comes from the multicast of the first processing unit. Steps (3) and (4) correspond to step S82 above.

[0184] (5) The second processing unit processes the scrambled downlink data of the user according to the first user information related to itself. This can be done in the following order: modulation, layer mapping, precoding, resource mapping, conversion from the watershed domain to the beam domain, inverse fast Fourier transform, and insertion of a cyclic prefix (see [link]). Figure 3 When the conversion from the water domain to the beam domain is performed, the first shaping weight associated with itself is used. Except for the conversion from the water domain to the beam domain, the other processes can be implemented based on existing technologies, thereby further obtaining the downlink baseband data corresponding to each antenna.

[0185] (6) After completing the conversion from downlink baseband data to radio frequency data, the second processing unit sends radio frequency data to the air interface. Steps (5) and (6) correspond to steps S83 and S84 above. The radio frequency data is the downlink air interface data mentioned above.

[0186] In this example, the uplink data transmission method according to the embodiment of this application involves the following process:

[0187] (7) The first processing unit generates second shaping weights that correspond one-to-one with multiple second processing units, and clarifies that all users use the same processing in each second processing unit, while generating the same second shaping weights for each second processing unit.

[0188] (8) The first processing unit passes through I e The interface sends second user information and second shaping weights to the second processing unit, wherein the second user information specifies how all second processing units should process uplink air interface data. Steps (7) and (8) correspond to step S91 above.

[0189] (9) The second processing unit accesses the front-end interface (I) e The interface obtains information related to itself, including second user information related to itself and the last-level second processing unit, and second shaping weights corresponding one-to-one with itself and the last-level second processing unit. Then, it forwards the second user information and second shaping weights related to the next-level second processing unit to the last-level second processing unit. Step (9) corresponds to step S92 above.

[0190] (10) The second processing unit receives uplink air interface data and performs the conversion from radio frequency data to uplink baseband data.

[0191] (11) The second processing unit processes the uplink baseband data according to the second user information related to itself, which may be in the order of removing the cyclic prefix, fast Fourier transform, beam domain to water domain conversion, and resource demapping (see Figure 3 When the conversion from beam domain to flow domain is performed, the second shaping weight associated with itself is used. Except for the conversion from beam domain to flow domain, the other processes can be implemented based on existing technologies to obtain the flow-level eCPRI interface data (in this example, the data after resource demapping).

[0192] (12) When the second processing unit does not receive uplink data, the second processing unit uses I... e The interface sends eCPRI interface data to the next higher-level second processing unit. At this time, the eCPRI interface data is the uplink data mentioned above.

[0193] (13) When the second processing unit receives uplink data, the second processing unit selects and adds the data processed by the same user in the same beam and frequency domain from the eCPRI interface data and the received uplink data. Specifically, it first needs to restore the received uplink data to the same scaling dimension as the local eCPRI interface data, and then merge it with the local eCPRI interface data in an equal ratio to obtain new eCPRI interface data, that is, the new uplink data mentioned above. Steps (10)-(13) correspond to step S93 mentioned above.

[0194] (14) The second processing unit sends new eCPRI interface data to the next higher-level second processing unit or the previous higher-level first processing unit. Step (14) corresponds to step S94 above. After the first processing unit finally receives the eCPRI interface data, it continues to perform existing channel estimation, combining, equalization, (inverse Fourier transform), demodulation, descrambling, rate matching dematching, decoding, and other operations (see [link to relevant documentation]). Figure 3 ).

[0195] This example employs the eCPRI fronthaul interface, increasing the processing capacity of the second processing unit while reducing the processing capacity requirements of the first processing unit. More importantly, it offers better scalability, allowing for smooth evolution to various operating modes such as selective transmit / receive, spatial multiplexing, and distributed Massive MIMO, without requiring a significant increase in fronthaul interface bandwidth. Furthermore, the example utilizes a chain-like architecture, which helps reduce network deployment complexity. When applied to a chain-like architecture digital distributed base station, this example enables a cell-merging operating mode, with wireless performance closer to that of a distributed antenna system, thus representing a relatively average performance mode. However, this mode is relatively simple to process, and each level of the second processing unit can achieve maximum data multicast or merging, thus possessing the potential for minimal fronthaul interface bandwidth. For example, with a 4T4R cascaded second processing unit, a fronthaul bandwidth of 6.25G or 10G is sufficient to support a 100M cell, even with 16 cascaded levels.

[0196] The following is another example of data transmission according to the data transmission method of the present application.

[0197] For example, the downlink cutoff point of the enhanced general public radio interface (eCPRI) can be pre-configured to II. D Interface, uplink split point is I e2 Interface (see) Figure 3 In this example, the first processing unit treats all the antennas of the second processing unit within the cell as a single unit, much like the antennas in a Massive MIMO. The exemplary manner of data transmission according to the data transmission method of this application is described below in two parts: downlink data processing and uplink data processing.

[0198] In this example, the downlink data transmission method according to the embodiment of this application involves the following process:

[0199] (15) The first processing unit generates first shaping weights corresponding to multiple second processing units in a distributed Massive MIMO manner, and clarifies the association between the user and all the second processing units. If the user is related to a certain second processing unit, the first shaping weights corresponding to the antenna of that second processing unit are generated. If the user is not related to a certain second processing unit, the first shaping weights corresponding to the antenna of that second processing unit are not generated, or the first shaping weights are set to zero.

[0200] (16) The first processing unit performs encoding, rate matching, scrambling, modulation, layer mapping, and precoding processing on the downlink data using existing technologies (see...). Figure 3 The precoded downlink data is obtained and processed via II DThe interface sends user-precoded downlink data, first user information, and first beamforming weights to multiple second processing units. The precoded downlink data is multicast to all second processing units within the cell; the implementation of multicast can be found in the relevant description above. The first user information indicates which second processing units are associated with the user and how the precoded downlink data is processed. Only the generated first beamforming weights are sent; zeroed first beamforming weights are not sent. Steps (15) and (16) correspond to step S81 above.

[0201] (17) The second processing unit accesses the fronthaul interface (II) D The interface obtains information related to itself, including user-precoded downlink data, first user information related to itself to the last-level second processing unit, and first shaping weight corresponding to itself to the last-level second processing unit, wherein the user-precoded downlink data comes from the multicast of the first processing unit.

[0202] (18) The second processing unit forwards the user-precoded downlink data, the first user information related to the next-to-last-level second processing unit, and the first shaping weight corresponding to the next-to-last-level second processing unit to the next-level second processing unit, wherein the user-precoded downlink data comes from the multicast of the first processing unit. Steps (17) and (18) correspond to step S82 above.

[0203] (19) The second processing unit processes the user-precoded downlink data based on the first user information related to itself, which may be in the order of resource mapping, watershed to beam domain conversion, inverse fast Fourier transform, and insertion of cyclic prefix (see [link]). Figure 3 When the conversion from the water domain to the beam domain is performed, the first shaping weight corresponding to itself is used. Except for the conversion process from the water domain to the beam domain, the others can be implemented based on existing technologies, so that the downlink baseband data corresponding to each antenna can be further obtained.

[0204] (20) After completing the conversion from downlink baseband data to radio frequency data, the second processing unit sends radio frequency data to the air interface. Steps (19) and (20) correspond to step S83 above. The radio frequency data is the downlink air interface data mentioned above.

[0205] In this example, the uplink data transmission method according to the embodiment of this application involves the following process:

[0206] (21) The first processing unit generates second shaping weights associated with multiple second processing units in a distributed Massive MIMO manner, and clarifies the association between the user and all the second processing units. If the user is associated with a certain second processing unit, the second shaping weights corresponding to the antenna of that second processing unit are generated. If the user is not associated with a certain second processing unit, the second shaping weights corresponding to the antenna of that second processing unit are not generated, or the second shaping weights are set to zero.

[0207] (22) The first processing unit passes through I e2 The interface sends the second user information and the second shaping weight to the second processing unit, wherein the second user information specifies how all second processing units should process the uplink air interface data. Only the generated second shaping weight is sent; the second shaping weight set to zero may not be sent. Steps (21) and (22) correspond to step S91 above.

[0208] (23) The second processing unit accesses the front-end interface (I) e2 The interface obtains information related to itself, including second user information related to itself to the last level second processing unit and second shaping weights corresponding to itself to the last level second processing unit, and then forwards the second user information and second shaping weights related to the next level to the last level second processing unit. Step (23) corresponds to step S92 above.

[0209] (24) The second processing unit receives uplink air interface data and performs the conversion from radio frequency data to uplink baseband data.

[0210] (25) The second processing unit processes the uplink baseband data according to the second user information related to itself, which may be in the order of removing the cyclic prefix, fast Fourier transform, beam domain to flow domain conversion, resource demapping, channel estimation, combining, and equalization (see Figure 3 When the beam domain to flow domain conversion is performed, the second shaping weight associated with itself is used. Except for the beam domain to flow domain conversion process, the others can be implemented based on existing technologies to obtain the flow-level eCPRI interface data (in this example, the equalized data).

[0211] (26) When the second processing unit does not receive uplink data, the second processing unit uses I... e2 The interface sends eCPRI interface data to the next higher-level second processing unit. At this time, the eCPRI interface data is the uplink data mentioned above.

[0212] (27) When the second processing unit receives the uplink data, the second processing unit selects and adds data in the same flow domain and the same bit from the eCPRI interface data and the received uplink data. Specifically, it first needs to restore the received uplink data to the same scaling dimension as the local eCPRI interface data, and then merge it with the local eCPRI interface data in an equal ratio to obtain new eCPRI interface data, that is, the new uplink data mentioned above. Steps (24)-(27) correspond to step S93 mentioned above.

[0213] (28) The second processing unit sends new eCPRI interface data to the next higher-level second processing unit or the previous higher-level first processing unit. Step (28) corresponds to step S94 above. Finally, after the first processing unit receives the eCPRI interface data, it continues to perform existing technology operations such as (inverse Fourier transform), demodulation, descrambling, rate matching dematching, and decoding (see...). Figure 3 ).

[0214] This example achieves high performance with distributed Massive MIMO at a lower fronthaul bandwidth. Furthermore, since the fronthaul bandwidth of distributed Massive MIMO is directly related to the maximum number of beam domains supported simultaneously, a smaller configuration with fewer beam domains can be used in the initial stages of a digital distributed base station. This allows for a smaller initial allocation of resources to the first processing unit. As service demands increase, the number of beam domains can be gradually increased, thus building the network with lower initial investment costs while ensuring scalability. In addition, this example employs a chain-like architecture, which helps reduce network deployment complexity. When applied to a chain-like architecture digital distributed base station, this example implements the distributed Massive MIMO operating mode. It can further enhance performance based on spatial multiplexing by utilizing time synchronization and phase alignment, while also considering capacity and experience consistency across the coverage area, making it the relatively optimal operating mode. Meanwhile, this example can also work with less fronthaul bandwidth. Taking the cascaded second processing unit of 4T4R as an example, when a maximum of 4 beam domains or 4 data streams are supported at the same time, 10G fronthaul bandwidth can support 100M cells, even if cascaded to 16 levels; when a maximum of 16 beam domains or 16 data streams are supported at the same time, 25G fronthaul bandwidth can support 100M cells, even if cascaded to 16 levels.

[0215] Embodiments of this application also provide a data transmission system, including a first processing unit and multiple second processing units cascaded via a single optical fiber. An enhanced general-purpose wireless interface is used between the first processing unit and the next-level second processing unit, and between adjacent second processing units. The system is configured to implement the above data transmission method. See above for a description of the data transmission system. Figure 7 Examples.

[0216] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of an instruction containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved.

[0217] It should also be noted that each block in the block diagram and / or flowchart, as well as combinations of blocks in the block diagram and / or flowchart, can be implemented using hardware (such as circuits or ASICs (Application Specific Integrated Circuits)) that performs the corresponding function or action, or using a combination of hardware and software, such as firmware.

[0218] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, disclosure, and appended claims in carrying out the claimed invention. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit can implement several functions listed in the claims. While different dependent claims may recite certain measures, this does not mean that these measures cannot be combined to produce good results.

[0219] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A data transmission method, characterized in that, The method is applied to a data transmission system, which includes a first processing unit and multiple second processing units cascaded via a single optical fiber. An enhanced general-purpose wireless interface is used between the first processing unit and the next-level second processing unit, and between adjacent levels of second processing units. The method includes: The first processing unit generates a first shaping weight corresponding to each of the plurality of second processing units, and sends downlink data, first user information related to the plurality of second processing units, and the first shaping weight to the next level second processing unit; For each second processing unit, the second processing unit sends the downlink data to the next level second processing unit, as well as the first user information and the first shaping weight related to the next level to the last level second processing unit; For each second processing unit, when the first user information and the first shaping weight received by the second processing unit include first user information and first shaping weight related to itself, the received downlink data is processed according to the first user information and the first shaping weight related to itself to obtain downlink air interface data. For each second processing unit, when the second processing unit obtains the downlink air interface data, it sends the downlink air interface data to the user equipment through the air interface.

2. The method according to claim 1, characterized in that, The first shaping weight includes information indicating whether the user is related to each second processing unit. The first processing unit generates a first shaping weight corresponding one-to-one with each of the plurality of second processing units, including: Determine the downlink operating mode of the data transmission system based on the configuration information; Determine whether the user is related to each second processing unit; For each second processing unit associated with the user, a first shaping weight corresponding to that second processing unit is generated for the user according to the determined downlink operating mode.

3. The method according to claim 1 or 2, characterized in that, The first user information includes information indicating whether the user is associated with each second processing unit.

4. The method according to claim 1 or 2, characterized in that, The step of processing the received downlink data based on the first user information and the first shaping weight associated with itself to obtain downlink air interface data includes: When the first user information or the first shaping weight associated with itself indicates that the user is associated with itself, the first shaping weight associated with itself is used to convert the downlink data from the flow domain to the beam domain to obtain the downlink baseband data in the beam domain. The downlink air interface data is radio frequency data converted from the downlink baseband data.

5. The method according to claim 4, characterized in that, The downlink operating modes of the data transmission system include cell merging mode. In the cell merging mode, each second processing unit processes the downlink data, and the first shaping weight corresponding to each second processing unit is the same. Each second processing unit sends the downlink air interface data to the user equipment through the air interface. The maximum number of beam domains is equal to the number of antennas in the plurality of second processing units.

6. The method according to claim 4, characterized in that, The downlink operating modes of the data transmission system include selectable transmit / receive modes. In the selected transmit / receive mode, at least one second processing unit processes the downlink data. The air interface used by the at least one second processing unit is not allowed to be used by other users other than the user in other second processing units. The at least one second processing unit sends the downlink air interface data to the user equipment through the air interface. The maximum number of beam domains is equal to the number of antennas in the plurality of second processing units.

7. The method according to claim 4, characterized in that, The downlink operating modes of the data transmission system include spatial multiplexing mode. In the spatial multiplexing mode, at least one second processing unit processes the downlink data. The air interface used by the at least one second processing unit is allowed to be used by other users besides the user in other second processing units. The at least one second processing unit sends the downlink air interface data to the user equipment through the air interface. The maximum number of beam domains is the product of the number of antennas of the plurality of second processing units and the preset spatial multiplexing coefficient.

8. The method according to claim 2, characterized in that, The downlink operating modes of the data transmission system include distributed massive MIMO mode. In the distributed massive MIMO mode, at least one second processing unit processes the downlink data, and the first processing unit generates a first shaping weight corresponding to the at least one second processing unit for each beam domain. The maximum number of beam domains is associated with the number of antennas in the plurality of second processing units.

9. A data transmission method, characterized in that, The method is applied to a data transmission system, which includes a first processing unit and multiple second processing units cascaded via a single optical fiber. An enhanced general-purpose wireless interface is used between the first processing unit and the next-level second processing unit, and between adjacent levels of second processing units. The method includes: The first processing unit generates a second shaping weight corresponding to each of the plurality of second processing units, and sends the second user information and the second shaping weight related to the plurality of second processing units to the next level second processing unit; For each second processing unit, the second processing unit sends the second user information and the second shaping weight related to the next level to the last level of the second processing unit to the next level of the second processing unit. For each second processing unit, when the second processing unit does not receive uplink data, the second processing unit processes the received uplink air interface data and the second user information and the second shaping weight related to itself to obtain uplink data. When the second processing unit receives uplink data, the second processing unit processes the received uplink air interface data, the uplink data and the second user information and the second shaping weight related to itself to obtain new uplink data. For each second processing unit, the second processing unit sends the processed uplink data to the next higher level second processing unit or the previous higher level first processing unit.

10. The method according to claim 9, characterized in that, The second shaping weight includes information indicating whether the user is related to each second processing unit. The first processing unit generates a second shaping weight corresponding one-to-one with each of the plurality of second processing units, including: Determine the uplink operating mode of the data transmission system based on the configuration information; Determine whether the user is related to each second processing unit; For each second processing unit associated with the user, a second shaping weight corresponding to that second processing unit is generated for the user according to the determined uplink operating mode.

11. The method according to claim 9 or 10, characterized in that, The second user information includes information indicating whether the user is associated with each second processing unit.

12. The method according to claim 9 or 10, characterized in that, When the second processing unit does not receive uplink data, it processes the received uplink air interface data and related second user information and second beamforming weights to obtain uplink data. When the second processing unit receives uplink data, it processes the received uplink air interface data, the uplink data, related second user information and second beamforming weights to obtain new uplink data, including: When the second user information or the second shaping weight indicates that the user is related to itself, the second processing unit converts the uplink air interface data into uplink baseband data in the beam domain, and uses the second shaping weight related to itself to convert the uplink baseband data from the beam domain to the water domain to obtain the enhanced general public radio interface data of the water domain. When the second processing unit does not receive uplink data, the enhanced general public radio interface data is used as the uplink data; When the second processing unit receives uplink data, it merges the received uplink data with the enhanced general public radio interface data, and uses the merged data as the new uplink data.

13. The method according to claim 12, characterized in that, The process of merging the received uplink data with the enhanced general public radio interface data includes: The received uplink data and the enhanced general public radio interface data processed by itself are combined with the data corresponding to the same user, which are obtained by processing uplink baseband data in the same beam domain and uplink air interface data in the same frequency domain. The received uplink data and the enhanced general public radio interface data obtained through its own processing are merged to identify data from the same user, the same flow domain, and the same bit.

14. The method according to claim 12, characterized in that, The uplink operating modes of the data transmission system include cell merging mode. In the cell merging mode, each second processing unit processes the uplink air interface data, and the second shaping weights corresponding to each second processing unit are the same. Each second processing unit receives the uplink air interface data from the user equipment through the air interface. The maximum number of beam domains is equal to the number of antennas in the plurality of second processing units.

15. The method according to claim 12, characterized in that, The uplink operating mode of the data transmission system includes selecting transmit / receive mode. In the selected transmit / receive mode, at least one second processing unit processes the uplink air interface data. The air interface used by the at least one second processing unit is not allowed to be used by other users other than the user in other second processing units. The at least one second processing unit receives the uplink air interface data from the user equipment through the air interface. The maximum number of beam domains is equal to the number of antennas in the plurality of second processing units.

16. The method according to claim 12, characterized in that, The uplink operating mode of the data transmission system includes spatial multiplexing mode. In the spatial multiplexing mode, at least one second processing unit processes the uplink air interface data. The air interface used by the at least one second processing unit is allowed to be used by other users besides the user in other second processing units. The at least one second processing unit receives the uplink air interface data from the user equipment through the air interface. The maximum number of beam domains is the product of the number of antennas of the plurality of second processing units and the preset spatial multiplexing coefficient.

17. The method according to claim 10, characterized in that, The uplink operating modes of the data transmission system include distributed massive MIMO mode. In the distributed massive MIMO mode, at least one second processing unit processes the uplink air interface data, and the first processing unit generates a second shaping weight corresponding to at least one second processing unit for each beam domain. The maximum number of beam domains is associated with the total number of antennas of the plurality of second processing units.

18. A data transmission system, characterized in that, The system comprises a first processing unit and multiple second processing units cascaded via a single optical fiber, wherein the first processing unit and the next-level second processing unit, and between adjacent levels of second processing units, employ an enhanced general public wireless interface, and the system is configured to implement the method of any one of claims 1-8, and / or implement the method of any one of claims 9-17.

Images