The present disclosure relates to wireless communication devices and communication control methods.
Background technology
[0002]
　Currently, as a configuration of a base station system that provides wireless services, a baseband processing unit (BBU; Base Band Unit) that processes a baseband signal and a wireless unit (RRH; Remote) that transmits and receives radio waves from an antenna Separate base stations that are separated from Radio Head) are the mainstream. Documents that disclose such a separate base station include, for example, Patent Documents 1 and 2.
Prior art literature
Patent documents
[0003]
Patent Document 1: Japanese Patent Application Laid-Open No. 2018-14697
Patent Document 2: Japanese Patent Application Laid-Open No. 2018-23035
Outline of the invention
Problems to be solved by the invention
[0004]
　Among the configurations of such separated base stations, when the BBU is arranged on a cloud base on the network and the RRH has a simple configuration of an antenna, an RF circuit, and an AD / DA converter, data processing delay is delayed. How to suppress is important.
[0005]
　Therefore, in the present disclosure, a new and improved wireless communication device and a communication control method capable of effectively suppressing data processing delay in a configuration of a separate base station in which a BBU is arranged on a cloud base on a network are provided. suggest.
Means to solve problems
[0006]
　According to the present disclosure, a wireless communication unit including an antenna element, a processing unit that executes signal processing on a part of data of a signal output from the antenna element in preference to other data, and the processing. Provided is a wireless communication device including an output unit that outputs the data to a device on the core network side.
[0007]
　Further, according to the present disclosure, a receiving unit that receives information about a part of data preferentially processed by the wireless communication device from a wireless communication device of a communication partner, and a component based on the information about the part of the data. A wireless communication device including a processing unit for selecting a carrier is provided.
[0008]
　Further, according to the present disclosure, signal processing is performed on a part of the data of the signal output from the antenna element in preference to other data, and the processed data is output to the device on the core network side. Communication control methods are provided, including.
[0009]
　Further, according to the present disclosure, it is based on receiving information about a part of the data preferentially processed by the wireless communication device from the wireless communication device of the communication partner and based on the information about the received part of the data. Communication control methods are provided, including selecting a component carrier.
The invention's effect
[0010]
　As described above, according to the present disclosure, a new and improved wireless communication device capable of effectively suppressing data processing delay in a configuration of a separate base station in which a BBU is arranged on a cloud base on a network. And a communication control method can be provided.
[0011]
　It should be noted that the above effects are not necessarily limited, and together with or in place of the above effects, any of the effects shown herein, or any other effect that can be grasped from this specification. May be played.
A brief description of the drawing
[0012]
FIG. 1 is an explanatory diagram showing a schematic configuration of a RAN.
FIG. 2 is an explanatory diagram showing a schematic configuration of NR.
FIG. 3 is an explanatory diagram showing an arrangement example of RRH and BBU.
[Fig. 4] Fig. 4 is an explanatory diagram showing an Analogue / Digital Hybrid Antenna architecture.
FIG. 5 is an explanatory diagram showing that data of a plurality of RRHs are aggregated by a switch in front of the BBU.
FIG. 6 is an explanatory diagram showing a format of an I / Q data container.
FIG. 7 is an explanatory diagram showing a configuration example of RRH according to the embodiment of the present disclosure.
FIG. 8 is an explanatory diagram showing an example in which data after AD conversion is stored as two-dimensional complex data.
FIG. 9 is an explanatory diagram showing a configuration of a normal RRH and BBU.
FIG. 10 is an explanatory diagram showing a configuration of RRH and BBU corresponding to the present embodiment.
FIG. 11 is an explanatory diagram showing a functional configuration example of RRH100 and BBU200 according to the embodiment of the present disclosure.
FIG. 12 is an explanatory diagram showing that among the 10 CCs, 3 CCs are CCs with a short delay.
[Fig. 13] Fig. 13 is a flow chart showing a conventional connection procedure.
FIG. 14 is a flow chart showing the operations of the RRH100, BBU200, MME, and terminal according to the present embodiment.
[Fig. 15] Fig. 15 is a flow chart showing an example of a procedure when the core network functions required for the Attach procedure are provided inside the RRH.
FIG. 16 is an explanatory diagram showing an example of having four BWPs in one component carrier.
FIG. 17 is an explanatory diagram showing a configuration example of a base station according to the present embodiment.
FIG. 18 is an explanatory diagram showing a configuration example of a base station according to the present embodiment.
FIG. 19 is an explanatory diagram showing an example of an enable signal sent from the BBU to the RRH.
FIG. 20 is an explanatory diagram showing an arrangement example of RRH and BBU.
FIG. 21 is a flow chart showing an operation example of a base station according to the embodiment of the present disclosure.
FIG. 22 is an explanatory diagram illustrating an example of a configuration of a terminal device according to an embodiment of the present disclosure.
Mode for carrying out the invention
[0013]
　Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.
[0014]
　The explanations will be given in the following order.
　1. 1. Embodiments of the present disclosure
　　1.1. Background
　　1.2. Description of Embodiment
　2. summary
[0015]
　<1. Embodiments of the present disclosure>
　[1.1. Background]
　Before explaining the embodiment of the present disclosure in detail, the background of the embodiment of the present disclosure will be described.
[0016]
　As described above, a separate base station in the form of being separated into a baseband processing unit (BBU) that processes a baseband signal and a radio unit (RRH) that transmits and receives radio waves from an antenna has become the mainstream. ing. Here, as an interface between the baseband processing unit and the radio unit, for example, a general-purpose interface such as a CPRI (Common Public Radio Interface) standard is defined. In the CPRI standard, the baseband processing unit is also called a radio control device (Radio Equipment Controller: REC), and the radio unit is also called a radio device (Radio Equipment: RE). Further, in the CPRI standard, user data (also referred to as U-plane data, digital baseband signal, or data signal) transmitted between a wireless control device and a wireless device is also referred to as IQ (In-phase and Quadrature) data. ..
[0017]
　(About New Radio Access and New Core) In
　3GPP (Third Generation Partnership Project), NR (New Radio Access) is being considered as a successor to RAN (Radio Access Network) called LTE (Long Term Evolution). FIG. 1 is an explanatory diagram showing a schematic configuration of a RAN. FIG. 2 is an explanatory diagram showing a schematic configuration of NR. In addition, New Core is being studied as a successor to the core network (CN) called EPC (Evolved Packet Core).
[0018]
　The feature of NR is to realize high-speed and large-capacity communication using a frequency band from 6 GHz to 100 GHz. The cellular system consists of RAN and CN. Most of the cost of the cellular system is required in the RAN part. This is because the number of units installed is several thousand compared to CN, which is extremely large. The CN is considered to be at the level of dozens of units.
[0019]

　Base stations 　(for C-RAN) require a great deal of computer cost. However, the number of terminals connected to each base station changes over time. Not all base stations always use the maximum processing power. Therefore, if the capacity of the computer of the base station can be shared among a plurality of base stations, the cost of the computer can be reduced. It is also possible to reduce the power consumed by the base station.
[0020]
　The base station is composed of an analog part consisting of an antenna and an RF circuit, an AD / DA converter arranged at the boundary between the analog part and the digital part, and a digital part that performs complicated digital signal processing. The digital part can be configured by an FPGA (Field Programmable Gate Array) or a DSP (Digital Signal Processor), but it has also become possible to process it with a general-purpose computer.
[0021]
　C-RAN (Cloud RAN, Centralized RAN, Clean RAN) is a RAN that can process a huge amount of calculation using a server on the network side.
[0022]
　As described above, consider the case where the functions of the base station are separated into two, RRH and BBU. For example, the antenna, the RF circuit, and the AD / DA converter are arranged in the RRH, and the other digital signal processing parts of the PHY / MAC of the digital part are arranged in the BBU. C-RAN processes the BBU part in the cloud.
[0023]
　Since the BBU portion arranged in the cloud can process the BBUs of a plurality of base stations on a common server, the cost of the base stations can be reduced. Since it is sufficient to prepare a general-purpose processing server corresponding to the processing amount required for a plurality of base stations, low cost can be realized.
[0024]
　On the other hand, base stations need to be located in many places. In particular, as the frequency used becomes higher, the range covered by one base station becomes narrower, and it is required to arrange an extremely large number of base stations. Therefore, further cost reduction of RRH is very required.
[0025]
　From the above, it can be said that the future cellular network is likely to be composed of C-RAN RRH and BBU. FIG. 3 shows a conceptual diagram in which a BBU is arranged inside a server inside a house and an RRH is connected to an outdoor antenna unit by a front hall which is an optical fiber. The BBU is connected to the core network by an optical fiber that is a backhaul. Of course, optical fiber is a typical example and can be replaced by ADSL or wireless communication.
[0026]
　Table 1 shows an example of the function of RRH, and Table 2 shows an example of the function of BBU.
[0027]
[table 1]

[0028]
[Table 2]

[0029]
　(Front hole and back hole) As
　shown in FIG. 3, the front hole is between RRH and BBU, and the back hole is between BBU and S-GW. The front hall is the interface required by separating the base station into RRH and BBU. The front hall may be connected wirelessly, but usually it is connected by a wired optical interface.
[0030]
　The communication speed required for a conventional front hall is generally said to be about 10 Gbps. In the front hall, it is necessary to transfer the data after AD conversion or before DA conversion, and it is necessary to transfer the data as the signal point of the I / Q axis. Therefore, the data required for the interface of the front hall. The transfer speed is high.
[0031]
　On the other hand, the data flowing through the backhaul interface is a bit string determined from the signal points on the I / Q axis. Since the amount of data flowing through the backhaul interface is a bit string determined by integrating signals from a plurality of antennas, the maximum amount is several Gbps. The backhaul is an interface between a gateway (S-GW in EPC terms) that bundles multiple base stations.
[0032]
　Therefore, since the switch in the previous stage of the S-GW needs to bundle information from several tens to several thousand base stations, a processing capacity of several terabits / s is required. Therefore, data processing in the core network is not easy at all, but the processing speed can be reduced by placing the BBU on the cloud side and offloading the traffic. On the other hand, in the front hall, a single line is required to have a speed of about 10 Gbps even at present. Therefore, the front hole is a critical point.
[0033]
　(Data transfer speed required in the
　front hall ) The data transfer speed required in the front hall depends on the number of AD / DA converters. Usually, an AD converter often requires a larger number of bits than a DA converter. For example, if the AD converter expresses the waveform with 10 bits, the DA converter expresses the waveform with 8 bits. As a matter of course, as the number of bits of the AD converter increases, the data transfer speed required for the front hole increases.
[0034]
　The sampling rate of the AD converter also affects the data transfer speed. When the frequency bandwidth operated by RAN is 20 MHz, an AD converter of 40 Mbps (sampling per second) is required. This is due to the sampling theorem that it is necessary to sample at twice the frequency being handled. Since a wide band frequency bandwidth such as 1 GHz is assumed for 5 G NR, the sampling frequency required for the AD converter is 2 Gps.
[0035]
　The next factor that affects is the number of component carriers. A maximum of 32 component carriers (CC) having a width of 1 GHz can be used. This is called carrier aggregation. As the number of component carriers increases, the burden on the front hall increases accordingly.
[0036]
　The next factor that affects is the number of AD converters. For example, if there are 30 antennas, 30 AD converters are required.
[0037]
　Table 3 summarizes the factors that affect the transfer speed of the front hole.
[0038]
[Table 3]

[0039]
　According to Table 3, the maximum transfer rate of the front hole is 12 × 2G × 32 × 32 = 24 Tbps.
[0040]
　(About Hybrid Antenna architecture)
　For example, when a base station has 256 antennas, a DA / AD converter corresponding to all the antennas may be required. This is called Full Digital Antenna architecture. In this case, since the amplitude and phase of all the antennas can be adjusted in the digital region, the degree of freedom of the directivity of the antennas is the largest. It is also possible to have different antenna directivity for each different frequency.
[0041]
　However, this method also increases the RF circuit and requires many AD / DA converters. Furthermore, the amount of signal processing in the digital domain also increases.
[0042]
　Therefore, we came up with the Analogue / Digital Hybrid Antenna architecture. As shown in FIG. 4, the number of branches that can digitally adjust both amplitude and phase is reduced by connecting to a plurality of antennas in the analog section via a phase shifter that can adjust only the phase. It is an architecture called. Considering the impact on the front hall, it is desirable to use a hybrid antenna architecture that can reduce the number of branches.
[0043]
　(Various Use Cases)
　Here, Table 4 shows the front hole throughput required for each use case in consideration of the above-mentioned Hybrid Antenna architecture.
[0044]
[Table 4]

[0045]
　The speed of a normal Ethernet (registered trademark) cable is about 1 Gbps. In addition, although optical fibers are drawn to homes, the maximum speed as a service is 1 Gbps. It is considered that this is because there is a possibility that it cannot be effectively used even if the speed is 1 Gbps or more, considering that it is connected to the Ethernet (registered trademark) cable.
[0046]
　At present, it can be said that the speed of the front hall that can be tolerated in a home or an office is about 1 Gbps. Therefore, at present, only use case 1 can realize C-RAN. Of course, for other use cases, the techniques described below are not inapplicable.
[0047]
　The capacity of the optical fiber itself is 10 Gbps in the case of the time division multiplexing method, and 10 Tbps can be transferred by using the wavelength division multiplexing method or multi-value modulation. For those actually used commercially, 10 Gbps is considered to be the maximum value. Therefore, when a dedicated optical fiber is pulled for an outdoor RRH, 10 Gbps is used for the front hall, and when an RRH is pulled for a home, 1 Gbps is the communication speed that can be used for the front hall. Of course, it is possible that communication at a higher speed can be used for the front hall.
[0048]
　(Common Public Radio Interface (CPRI))
　There is a CPRI standard. Option 1 is 614.4 Mbit / s, and Option 10 is a front hole capable of transmitting 24.33 Gbit / s. Basically, it defines how the synchronization signal comes and how the I / Q data is multiplexed by TDM, and is not a standard for how to reduce the signal to be transmitted.
[0049]
　The I / Q bit string itself is defined as an I / Q bit string (AxC container) for one antenna and one carrier. For a plurality of antennas and component carriers, this AxC container is multiplexed. Although CPRI is not a standard in 3GPP, it is stipulated that it can be applied to 3GPP, and in the future, CPRI may be incorporated and standardized for the purpose of examining the standard of 3GPP.
[0050]
　(Regarding the received data and transmitted data of the
　base station ) The data received by the base station often requires a larger amount of data than the data transmitted. This embodiment can be applied to both reception and transmission of the base station, but first, the technique will be described using the signal flow on the reception side of the base station. The reason for this is that wireless signal processing generally requires a larger signal processing capacity on the receiving side, and C-RAN is essentially aimed at reducing signal processing on the receiving side. This is because I think it is important to explain in the processing of.
[0051]
　[1.2. Description of the Embodiment]
　(Format of data container of I / Q) When
　a bit string corresponding to one antenna and one component carrier is defined as a container which is one processing unit, as shown in FIG. 6, between different antennas. The relationship is completely separated. Considering that compression is performed by using the fact that the data received by different antennas are correlated, it is easier to compress the information by the compression algorithm if the information of a plurality of antennas is stored in one container.
[0052]
　In the present embodiment, the RRH stores information from an AD converter corresponding to a plurality of antenna elements corresponding to one time in one container. Then, the RRH according to the present embodiment creates a data structure of the front hall by arranging the containers in chronological order. Since the correlated signals received by the plurality of antenna elements are stored in the same container by RRH, there is an advantage that they can be easily compressed before being stored in the container. Also, when processing data on the BBU side of the cloud, it is easier to process when the information of a plurality of antenna elements arrives at the same time. This is because it is possible to solve the drawback that it is necessary to wait for the data of a plurality of antenna elements when the antenna signal processing is performed on the BBU side.
[0053]
　The two-dimensional array antenna has a configuration in which antenna elements are arranged in the vertical direction and the horizontal direction. The input of radio waves to each antenna element is only out of phase, and basically the same signal arrives. This is true when the signal source is far enough compared to the distance between the antenna elements (called a distant solution approximation).
[0054]
　Therefore, the information between the antenna elements can be compressed by the information compression algorithm. The phase difference between the antennas differs depending on the direction in which the signal generation source arrives. For example, if a compression algorithm used for compressing a normal moving image is used, the phase difference between the antennas can be reduced. It can be compressed in an inclusive form.
[0055]
　In the present embodiment, when the antenna element is arranged two-dimensionally like a two-dimensional array antenna, the I / Q information is arranged like a pixel of video data while maintaining the two-dimensional structure, and the I / The information of Q is packed in a container so as to keep the time, that is, the data at different times becomes a two-dimensional image at different times.
[0056]
　Here, there is no concept of I / Q in the image, but there is a method based on the two-dimensional discrete Fourier transform for the compression of the image system. In this case, since the input data to the two-dimensional discrete Fourier transform can be given as a complex number, two-dimensional complex data can be obtained from the data in which the antenna is arranged in two dimensions. Data can be compressed by extracting low-frequency components after performing a two-dimensional Fourier transform on two-dimensional complex data.
[0057]
　FIG. 7 is an explanatory diagram showing a configuration example of RRH according to the embodiment of the present disclosure. The RRH 100 shown in FIG. 7 includes a two-dimensional array antenna 110, an RF circuit 120, an AD conversion unit 130, a two-dimensional data creation unit 140, a data compression unit 150, and an E / O conversion unit 160.
[0058]
　The two-dimensional array antenna 110 has antennas arranged in an array shape for receiving radio waves from a terminal as a communication partner and transmitting radio waves toward the terminal. The RF circuit 120 has two dimensions. This is an analog circuit that executes reception processing for the signal received by the array antenna 110 of the above. The RF circuit 120 may include a mixer, a filter, an amplifier, and the like.
[0059]
　The AD conversion unit 130 is a circuit that converts an analog signal output by the RF circuit 120 into a digital signal. The two-dimensional data creation unit 140 generates two-dimensional complex data as described later from the data output by the AD conversion unit 130. The data compression unit 150 executes a compression process on the two-dimensional complex data generated by the two-dimensional data creation unit 140. Then, the E / O conversion unit 160 converts an electric signal into an optical signal for transmission from the RRH to the BBU via an optical fiber.
[0060]
　Further, FIG. 8 shows an example in which the data after AD conversion from the antennas arranged in two dimensions is stored as two-dimensional complex data by the two-dimensional data creation unit 140. D (i, j) indicates that the I / Q data corresponds to the i-th in the vertical direction and the j-th in the horizontal direction.
[0061]
　Since the data of FIG. 8 is the data of the two-dimensional antenna at one time, the data of FIG. 8 is arranged in chronological order to be a series of data. The container may be delimited as shown in FIG. 8, or may be packed in the container at regular intervals. Here, the time of a certain degree is a unit of time for one sample of the AD converter. What is important here is to convey the information of the number of vertical and horizontal images (4 × 4 in the example of FIG. 8) to the compression algorithm in the data compression unit 150. That is the interface between the container block (two-dimensional data creation unit 140) and the compression function (data compression unit 150). This notification itself may be set as a base station configuration or as a standard.
[0062]
　The number of analog circuits is limited in one RRH. Therefore, the connection between the antenna and the analog circuit may be changed in one RRH. In that case, the RRH100 also changes the number of antennas in the horizontal and vertical directions of the array antenna, so that the container is recombined in response to the change and the size is notified to the BBU. As a result, the BBU can decompress the compressed data even if the connection between the antenna and the analog circuit is changed in the RRH.
[0063]
　The base station for C-RAN is composed of RRH and BBU. The RRH can be located near the terminal, for example, within tens to hundreds of meters of the terminal. The RRH is connected via an optical fiber to a BBU located on a server having abundant computer resources in the station building. The distance between the RRH and the BBU may range from a few kilometers to a few tens of kilometers.
[0064]
　In addition to passing through many switches provided between RRH and BBU, there is also a delay in transmission by optical fiber, so compared to the case where all processing is performed by RRH, signal processing by BBU delays. Tends to increase.
[0065]
　In recent years, there have been an increasing number of use cases in which a delay amount of 1 ns (or 1 ns or less) is required for wireless communication. For example, it is a use case where real-time performance is extremely required, such as control of a car, a drone (flying object), or a robot. Therefore, when the BBU is arranged on a server having abundant computer resources in the station building, it is required to reduce the processing delay of the base station having the RRH and BBU configurations.
[0066]
　A base station composed of RRH and BBU can transmit and receive a plurality of component carriers (CC). For example, a base station can provide services by bundling five 20 MHz component carriers. Performing transmission / reception by bundling a plurality of component carriers in this way is called carrier aggregation (CA).
[0067]
　In carrier aggregation, there are PCC (Primary Component Carrier) and SCC (Secondary Component Carrier). The PCC is used to perform an important signaling procedure called NAS signaling performed when a UE (User Equipment; terminal) starts communication with a control station such as an MME (Mobility Management Entity) of a core network. In order to reduce the delay when the UE connects to the network during carrier aggregation, it is important to reduce the delay when using the PCC.
[0068]
　Therefore, in the present embodiment, for some component carriers, for example, PCC, the function to be processed by the BBU is also arranged on the RRH side for processing, and the remaining BBU function of the SCC is the BBU arranged on the cloud. It is characterized by doing in. RRH also has a function of processing by BBU, and by performing PCC processing, it is possible to shorten the delay at the time of carrier aggregation.
[0069]
　FIG. 9 is an explanatory diagram showing the configuration of a normal RRH and BBU. That is, in the configuration of FIG. 9, the AD-converted I / Q data corresponding to all CC1, CC2, ..., CC5 is sent from RRH to BBU, and all CC1, CC2, ..., CC5 BBU. The function of is performed in BBU.
[0070]
　On the other hand, FIG. 10 is an explanatory diagram showing the configuration of RRH and BBU corresponding to the present embodiment. In the configuration of FIG. 10, when the PCC of a specific UE is CC2, both the RRH function of CC2 and the function of BBU for that UE are arranged in RRH and processed by RRH.
[0071]
　FIG. 11 is an explanatory diagram showing an example of functional configuration of RRH100 and BBU200 according to the embodiment of the present disclosure.
[0072]
　The RRH100 shown in FIG. 11 includes an antenna circuit unit 111, an AD conversion unit 130, a data creation unit 140, a selector 142, a fast Fourier transform unit 144, a control unit 146, a data compression unit 150, an E / O conversion unit 160, and O. It is configured to include the / E conversion unit 170.
[0073]
　The BBU 200 shown in FIG. 11 includes an O / E conversion unit 210, a data decompression unit 220, a fast Fourier transform unit 230, and a control unit 240.
[0074]
　The antenna circuit unit 111 includes, for example, a two-dimensional array antenna and an analog circuit (RF circuit) that executes reception processing for the signal received by the array antenna. The array antenna is an antenna arranged in an array shape for receiving radio waves from a terminal as a communication partner and transmitting radio waves toward the terminal.
[0075]
　The AD conversion unit 130 is a circuit that converts an analog signal output by the RF circuit into a digital signal. The data creation unit 140 generates an I / Q data string from the data output by the AD conversion unit 130. The data compression unit 150 executes a compression process on the I / Q data string generated by the data creation unit 140. Then, the E / O conversion unit 160 converts an electric signal into an optical signal for transmission from the RRH to the BBU 200 by an optical fiber. The O / E conversion unit 170 acquires the data transmitted from the BBU 200. Further, the fast Fourier transform unit 144 executes the fast Fourier transform process on the data generated by the data creation unit 140. The control unit 146 includes, for example, decoding of data after a fast Fourier transform process by the fast Fourier transform unit 144.
[0076]
　The O / E conversion unit 210 converts an optical signal sent from the RRH 100 by an optical fiber into an electric signal. The data decompression unit 220 decompresses the data compressed by the RRH 100 and restores the data. The fast Fourier transform unit 230 executes a fast Fourier transform process on the data restored by the data decompression unit 220. The control unit 240 executes the basic functions of the BBU 200. The basic functions of the BBU200 include, for example, data decoding, scheduling processing, and QoS control.
[0077]
　Among these, the one that requires time for processing is the fast Fourier transform processing by the fast Fourier transform unit 230. Therefore, for the CC that executes the fast Fourier transform process, if the fast Fourier transform process can be executed by the fast Fourier transform unit 144 inside the RRH100 instead of the BBU200, the data processing can be speeded up.
[0078]
　Here, as the configuration of the RRH100, as shown in FIG. 11, the connection between the CC and the BBU can be set by the selector 142. Regarding this connection switching, the O / E conversion unit 170 receives an instruction from the BBU 200 located on the cloud side. By having such a configuration, the processing of the PCC of the UE becomes faster than the processing of other CCs.
[0079]
　The PCC is different for each UE. Therefore, it is not desirable to decide to process CC with a fixed frequency in both RRH and BBU. This is because the PCC is different for each UE. Therefore, unlike the existing base station, in the present embodiment, the base station informs the UE in advance that the CC has a short delay time.
[0080]
　FIG. 12 is an explanatory diagram showing that among the 10 CCs 1 to CC10, 3 CC1, CC4, and CC7 are CCs having a short delay. Then, the base station notifies the UE of the CC information having a short delay by the system information. The UE selects the PCC from the three CC1, CC4, and CC7 having the shortest delay. This makes it possible for all UEs to select any of the three CC1, CC4, and CC7 as the PCC.
[0081]
　In any case, as shown in FIG. 11, it is necessary to specify the CC that requires the processing performed by the BBU on the RRH side from the BBU on the cloud side to the RRH. The connection procedure in the conventional case is shown in FIG. The black circles in FIG. 13 indicate that the information needs to be received and transferred. The part of the arrow indicates the transmission / reception point. FIG. 13 shows an example in which a random access procedure is exchanged with a BBU placed in the cloud.
[0082]
　First, the BBU generates synchronization signals for all component carriers and transfers them to the RRH (step S101). The RRH transmits the synchronization signal received from the BBU to the terminal (step S102).
[0083]
　Upon receiving the synchronization signal from the RRH, the terminal executes measurements for each component carrier (step S103). Then, as a result of the measurement, the terminal determines the primary component carrier from the low-delay component carriers (step S104).
[0084]
　Subsequently, a random access procedure is executed between the terminal, RRH, and BBU (step S105), and a connection procedure (Attach procedure) is executed between the terminal, RRH, BBU, and MME (step S106). .. Here, in the conventional procedure, the RRH needs to transfer the data from the UE to the BBU during the random access procedure. Further, when the connection procedure is executed, the data from the terminal is sent to the MME via RRH and BBU.
[0085]
　FIG. 14 is a flow chart showing the operations of the RRH100, BBU200, MME, and terminal according to the present embodiment. The BBU 200 located in the cloud notifies and controls the association to which CC among the plurality of CCs the function of one BBU in the RRH is connected (step S111). Then, the BBU 200 transmits the system information regarding the Low latency CC to the RRH 100 (step S112).
[0086]
　Based on the notification from the BBU 200, the RRH 100 selects the data to be sent to the BBU from the data of the plurality of CCs by the selector. Then, the RRH 100 provides the terminal as information on the Low latency CC, which CC can provide the low latency service because the function of the BBU 200 is in the RRH 100 (step S113).
[0087]
　The BBU 200 then generates synchronization signals for all component carriers and transfers them to the RRH100 (step S114). The RRH100 transmits the synchronization signal received from the BBU200 to the UE (step S115).
[0088]
　Upon receiving the synchronization signal from the RRH, the terminal performs measurements for each component carrier (step S116). Then, as a result of the measurement, the UE determines the primary component carrier from the low-delay component carriers (step S117).
[0089]
　Here, the terminal can know which CC of the Low latency is by the notification from the RRH100. Based on the notification from the RRH100, the terminal can select the CC for low delay and perform Random access (step S118). In this case, the response to the Random access can be created by RRH. Therefore, it is not necessary to transfer the Random access signal coming from the terminal to the BBU, so that low delay can be realized.
[0090]
　Further, the Attach procedure (step S119) by NAS signaling that starts after Random access does not need to use BBU for the NAS signaling reception process. However, in this case, since it is necessary to transfer the signal to the MME in the core network arranged toward the station building, it may not be possible to realize low delay. A method for dealing with this point will be described.
[0091]
　FIG. 15 is a flow chart showing an example of a procedure when the core network functions (MME and HSS in the case of LTE) necessary for the Attach procedure are provided inside the RRH100. By providing the core network function required for the Attach procedure inside the RRH in this way, low delay can be realized.
[0092]
　The BBU 200 transmits the system information regarding the Low latency CC to the RRH100 (step S121).
[0093]
　Based on the notification from the BBU 200, the RRH 100 selects the data to be sent to the BBU from the data of the plurality of CCs by the selector. Then, the RRH 100 provides the terminal as information on the Low latency CC, which CC can provide the low latency service because the function of the BBU 200 is in the RRH 100 (step S122).
[0094]
　The BBU 200 then generates synchronization signals for all component carriers and transfers them to the RRH100 (step S123). The RRH100 transmits the synchronization signal received from the BBU200 to the UE (step S124).
[0095]
　Upon receiving the synchronization signal from the RRH, the terminal performs measurements for each component carrier (step S125). Then, as a result of the measurement, the UE determines the primary component carrier from the low-delay component carriers (step S126).
[0096]
　Here, the terminal can know which CC of the Low latency is by the notification from the RRH100. The terminal can select a CC for low delay and perform Random access based on the notification from the RRH100 (step S127). In this case, the response to the Random access can be created by RRH. Therefore, it is not necessary to transfer the Random access signal coming from the terminal to the BBU, so that low delay can be realized.
[0097]
　Also, the Attach procedure (step S128) by NAS signaling that starts after Random access does not need to use BBU for the NAS signaling reception process. Furthermore, in this case, the core network functions required for the Attach procedure (MME and HSS in the case of LTE) are provided inside the RRH100, so they are included in the core network located near the station building. There is no need to transfer the signal to a certain MME. Therefore, further low delay can be realized by providing the core network functions (MME and HSS in the case of LTE) necessary for the Attach procedure inside the RRH100.
[0098]
　When there are multiple BWPs (Band width parts) in one CC, if the BWP processing that requires low delay is processed by the BBU200 in the station building on the cloud side, the demand for delay cannot be satisfied. In some cases.
[0099]
　Therefore, in the present embodiment, the base station notifies the UE of information as to which BWP can realize low delay by System Information or dedicated signaling. FIG. 16 is an explanatory diagram showing an example of having four BWPs in one component carrier. In this example, since BWP1 and BWP4 are BWPs capable of realizing Low latency, the information about the BWP is notified from the base station to the UE by System Information or dedicated signaling.
[0100]
　FIG. 17 is an explanatory diagram showing a configuration example of a base station according to the present embodiment. As shown in FIG. 17, it is characterized in that only the functions of BBU corresponding to BWP1 and BWP4 that realize low delay are arranged on the RRH100 side.
[0101]
　When the BBU 200 is on the cloud side, the delay increases, and when the number of RRH antennas is large, it is necessary to transfer signals corresponding to the number of antennas from the RRH to the BBU. Therefore, signal processing corresponding to the signals corresponding to the number of antennas is required in the BBU, and it is necessary to cope with the increase in capacity and the delay in the optical line.
[0102]
　When arranging a base station indoors or in an office, beamforming using a large number of antennas is not always necessary for communication because the distance between the base station and the terminal is short. A large number of antennas are required to improve the throughput, but if low latency is preferable because a throughput of several tens of Mbps is sufficient, I / Q bit data for the number of antennas from RRH is transferred to the BBU by optical fiber. The C-RAN configuration sent via is not an appropriate configuration.
[0103]
　Therefore, in the present embodiment, in the case of a bearer that requires low delay, it is possible to bring the BBU function to the RRH side instead of using a small number of antennas at the base station. FIG. 18 is an explanatory diagram showing a configuration example of a base station according to the present embodiment. When the base station adopts the configuration of FIG. 18, when to select the four antennas with low delay will be described.
[0104]
　The first method is that in a low-delay CC or a low-delay BWP, the base station uses only four antennas. In this case, it is desirable that the base station informs the UE in advance by System Information or dedicated signaling that only four antennas are used in the low-delay CC or low-delay BWP.
[0105]
　The second method is to link to QoS. For example, a low latency QoS bearer is a method of using four antennas. In this case, after making a bearer according to the normal LTE bearer establishment procedure, when the uplink signal corresponding to the bearer arrives, the signal is guided to the path for processing the signals of the four antennas. .. However, since the RRH usually does not know what kind of data the received data is, the BBU notifies by an enable signal whether the I / Q bit stream being received is the data for low delay. FIG. 19 is an explanatory diagram showing an example of notifying the RRH 100 of the enable signal from the BBU 200.
[0106]
　As described above, in the present embodiment, the BBU is arranged on a server at an arbitrary location on the Internet called a cloud. The BBU is then placed on a server on the network using virtualization technology such as a virtual machine. FIG. 20 is an explanatory diagram showing an arrangement example of RRH and BBU. Therefore, the location of the BBU can be changed each time there is a connection request from the RRH.
[0107]
　C-RAN composed of many RRHs and BBUs that accommodate many of them, when one BBU tries to accommodate more RRHs, the BBUs are placed far from a certain RRH. There are times.
[0108]
　When there is a request from the RRH to operate a low-latency application, the BBU corresponding to the RRH is placed on the edge side of the network to appropriately provide the BBU service to the RRH having a low-latency request. Will be possible. However, how much delay each RRH must achieve depends on the application used by the UE connected to the RRH.
[0109]
　Therefore, in the present embodiment, when the RRH first connects to the network, when the connection request to the BBU is made, the request for the delay is sent to the BBU arrangement management function on the core network side. When the RRH sends a request for delay to the BBU configuration management function on the core network side, the BBU configuration management function notifies the RRH of the IP address of the BBU after arranging the BBU in an appropriate place.
[0110]
　The RRH makes a connection request to the BBU having the notified IP address. The BBU grants connection permission in response to a connection request from RRH. The request for the delay is, for example, 2 bits and is notified by an indicator of 0 to 3. This notification should be included in the RRH-BBU setup request. Further, after the user sets the RRH, the RRH is connected to the Internet. The indicator can be set, for example, as follows.
　0: Very large
　delay request 1: Large delay request
　2: Small delay request
　3: No matter how late it may be (only an MTC terminal)
[0111]
　FIG. 21 is a flow chart showing an operation example of the base station according to the embodiment of the present disclosure. The RRH sends a request to connect to the BBU as an RRH-BBU setup request to the IP address of the control station of the core network set in advance as a default value (step S131).
[0112]
　The control station of the core network refers to the delay indicator included in its RRH-BBU setup request. As a result of the reference, if the delay request is high, the control station will ensure that the BBU is located as close as possible to the UE. The determination of the arrangement is sent from the control station to the corresponding server (step S132). At that time, the control station also notifies the IP address of the RRH.
[0113]
　When the server provisions the BBU function with a virtual machine or the like (step S133), the server then returns an RRH-BBU setup response to the corresponding RRH to inform that the BBU has been successfully provisioned (step S133). Step S134).
[0114]
　By arranging the BBU in this way, for example, when low-latency traffic occurs during the operation of the RRH, the RRH can also issue a request to the core network to arrange the BBU as close as possible.
[0115]
　Next, with reference to FIG. 22, an example of the configuration of the terminal device 300 according to the embodiment of the present disclosure will be described. FIG. 22 is a block diagram showing an example of the configuration of the terminal device 300 according to the embodiment of the present disclosure. Referring to FIG. 22, the terminal device 300 includes an antenna unit 310, a wireless communication unit 320, a storage unit 330, and a processing unit 340.
[0116]
　(Antenna unit 310) The
　antenna unit 310 radiates the signal output by the wireless communication unit 320 into space as a radio wave. Further, the antenna unit 310 converts a radio wave in space into a signal and outputs the signal to the wireless communication unit 320.
[0117]
　(Wireless Communication Unit 320) The
　wireless communication unit 320 transmits and receives signals. For example, the wireless communication unit 320 receives the downlink signal from the RRH 100 and transmits the uplink signal to the RRH 100.
[0118]
　(Storage unit 330) The
　storage unit 330 stores programs and data for the operation of the terminal device 300.
[0119]
　(Processing Unit 340) The
　processing unit 340 provides various functions of the terminal device 300. The processing unit 340 includes an information acquisition unit 341 and a communication control unit 343. The processing unit 340 may further include other components other than these components. That is, the processing unit 340 may perform operations other than the operations of these components.
[0120]
　In the present embodiment, the communication control unit 343 measures the component carrier and selects the component carrier based on the information notified from the RRH 100 acquired by the information acquisition unit 341. More specifically, the communication control unit 343 executes the processes shown in steps S116 and S117 of FIG. By making such a selection, the RRH 100 can quickly execute the processing for the component carrier selected by the terminal device 300, and can suppress the processing delay.
[0121]
　<2. Summary>
　By applying this embodiment, operators and users can arrange low-cost base stations in various places. In addition, the operator can provide the user with a service in a stable and inexpensive wireless communication environment by promoting the effective use of the frequency. Then, the user can enjoy the service by the stable and inexpensive wireless communication environment.
[0122]
　Each step in the process performed by each device of the present specification does not necessarily have to be processed in chronological order in the order described as a sequence diagram or a flowchart. For example, each step in the process executed by each device may be processed in an order different from the order described in the flowchart, or may be processed in parallel.
[0123]
　In addition, it is possible to create a computer program for making the hardware such as the CPU, ROM, and RAM built in each device exhibit the same functions as the configuration of each device described above. It is also possible to provide a storage medium in which the computer program is stored. Further, by configuring each functional block shown in the functional block diagram with hardware, a series of processes can be realized by hardware.
[0124]
　Although the preferred embodiments of the present disclosure have been described in detail with reference to the accompanying drawings, the technical scope of the present disclosure is not limited to such examples. It is clear that anyone with ordinary knowledge in the technical field of the present disclosure may come up with various modifications or modifications within the scope of the technical ideas set forth in the claims. Is, of course, understood to belong to the technical scope of the present disclosure.
[0125]
　In addition, the effects described herein are merely explanatory or exemplary and are not limited. That is, the techniques according to the present disclosure may exhibit other effects apparent to those skilled in the art from the description herein, in addition to or in place of the above effects.
[0126]
　The following configurations also belong to the technical scope of the present disclosure.
(1) A
　wireless communication unit including an
　antenna element, a processing unit that executes signal processing of a part of the signal output from the antenna element in preference to other data, and the signal-processed
　data. A
wireless communication device including an output unit that outputs data to a device on the core network side .
(2)
　The wireless communication device according to (1) above, wherein some of the data is data of some component carriers.
(3)
　The wireless communication device according to (2) above, wherein some of the component carriers are primary component carriers.
(4)
　The wireless communication device according to any one of (1) to (3) above, wherein some of the data is data for which the signal processing with low delay is required.
(5)
　The wireless communication device according to any one of (1) to (4) above, wherein the processing unit executes a high-speed Fourier transform process on a part of the data.
(6)
　The wireless communication device according to (5) above, wherein the processing unit executes a decoding process on the part of the data after the fast Fourier transform process.
(7)
　The wireless communication device according to any one of (1) to (6) above, further comprising an acquisition unit that acquires a control signal in the signal processing from the device.
(8)
　The wireless communication device according to (7) above, wherein the acquisition unit acquires information regarding designation of data to be processed by the processing unit.
(9)
　The wireless communication device according to (8), wherein the acquisition unit acquires information regarding designation of a component carrier to be processed by the processing unit.
(10)
　The wireless communication device according to any one of (1) to (9) above, wherein the output unit outputs a request regarding delay when requesting connection to the device on the core network side.
(11) The
　wireless communication device according to any one of (1) to (10) above, wherein the wireless communication unit transmits information of a carrier corresponding to a part of the data to a device of a communication partner.
(12) From
　the wireless communication device of the communication partner, a receiving unit that receives information on a part of the data preferentially processed by the wireless communication device, and
　a component carrier are selected based on the information on the part of the data. A wireless communication device including a processing unit.
(13)
　Performing the signal processing on a part of the data of the signal output from the antenna element in preference to other data, and
　outputting the processed data to the device on the core network side. ,
Communication control methods, including.
(14)
　Receive information about a part of the data preferentially processed by the wireless communication device from the wireless communication device of the communication partner,
　and select a component carrier based on the received information about the part of the data. Communication control methods, including what to do.
Code description
[0127]
　100 RRH
　200 BBU
　300 terminal device
The scope of the claims
[Claim 1]
　A wireless communication unit including an
　antenna element, a processing unit that executes signal processing of a part of the signal output from the antenna element in preference to other
　data, and a core network of the signal-processed data. A
wireless communication device including an output unit that outputs data to a device on the side .
[Claim 2]
　The wireless communication device according to claim 1, wherein some of the data is data of some component carriers.
[Claim 3]
　The wireless communication device according to claim 2, wherein some of the component carriers are primary component carriers.
[Claim 4]
　The wireless communication device according to claim 1, wherein some of the data is data for which the signal processing with low delay is required.
[Claim 5]
　The wireless communication device according to claim 1, wherein the processing unit executes a fast Fourier transform process on a part of the data.
[Claim 6]
　The wireless communication device according to claim 5, wherein the processing unit executes a decoding process on the part of the data after the fast Fourier transform process.
[Claim 7]
　The wireless communication device according to claim 1, further comprising an acquisition unit that acquires a control signal in the signal processing from the device.
[Claim 8]
　The wireless communication device according to claim 7, wherein the acquisition unit acquires information regarding designation of data to be processed by the processing unit.
[Claim 9]
　The wireless communication device according to claim 8, wherein the acquisition unit acquires information regarding designation of a component carrier to be processed by the processing unit.
[Claim 10]
　The wireless communication device according to claim 1, wherein the output unit outputs a request regarding delay when requesting connection to the device on the core network side.
[Claim 11]
　The wireless communication device according to claim 1, wherein the wireless communication unit transmits information of a carrier corresponding to a part of the data to a device of a communication partner.
[Claim 12]
　A receiving unit that receives information on a part of data that is preferentially processed by the wireless communication device from a wireless communication device of a communication partner,
　and a processing unit that selects a component carrier based on the information on the part of the data. , A wireless communication device.
[Claim 13]
　And that in preference to other data for some of the data of the signal output from the antenna elements to perform the signal processing,
　and outputting the signal processed data to the core network side of the device,
the Communication control methods, including.
[Claim 14]
　To receive information about a part of the data preferentially processed by the wireless communication device from the wireless communication device of the communication partner, and
　to select a component carrier based on the information about the received part of the data. Communication control methods, including.