WO2017168714A1 - Base station, terminal device, communications system, and communications method - Google Patents

Abstract

A base station (20) performing wireless communications between same and a terminal device comprises: a block setting unit (220), a DL RS insertion calculation unit (227), and a DL signal processing unit (224). The block setting unit (220) sets the OFDM symbol length for each block among a plurality of blocks generated in one carrier and having different frequency bands, setting same such that the OFDM symbol length for each block is an integer multiple of the block having the shortest OFDM symbol length among the blocks. The DL RS insertion calculation unit (227) calculates a second block subcarrier position at which the out-of-band interference from a first block to the second block becomes a null point. The DL signal processing unit (224) inserts a reference signal used in channel estimation for a wireless propagation path, into the subcarrier at the position calculated by the DL RS insertion calculation unit (227), and sends same to the terminal device.

Description

Base station, terminal device, communication system, and communication method

The present invention relates to a base station, a terminal device, a communication system, and a communication method.

5G (5th generation mobile communication) has been studied as a new wireless communication standard, but F-OFDM (Filtered-Orthogonal Frequency Division Multiplexing) has been proposed in order to use the wireless band more flexibly. F-OFDM is a technique for reducing interference between blocks by filtering processing even when OFDM signals in which different parameters are set on one carrier are placed as blocks and the blocks become non-orthogonal to each other.

Here, for example, in F-OFDM, one carrier may include blocks for different communication applications such as a V2X (Vehicle-to-Everything) communication block and an IoT (Internet of Things) communication block. In such a case, data that may affect human life may be handled in the V2X communication block. Therefore, it is possible to achieve high communication quality by increasing the transmission power compared to the IoT communication block. Conceivable.

However, if the transmission power difference between blocks in one carrier is large, out-of-band interference from a block with high transmission power to a block with low transmission power cannot be ignored even if filtering processing is performed. There is a fear.

The technique disclosed in the present application has an object to suppress deterioration in communication quality of a block that receives interference even in a situation where the block receives interference in F-OFDM.

In one aspect, a base station that performs wireless communication with a terminal device includes a setting unit, a calculation unit, and a signal processing unit. The setting unit sets the OFDM symbol length of each block in a plurality of different frequency bands generated on one carrier so that the OFDM symbol length of each block is an integral multiple of the shortest OFDM symbol length among the blocks. To do. The calculation unit calculates the position of the subcarrier of the second block where the out-of-band interference from the first block to the second block is a null point. In the downlink signal, the signal processing unit inserts a reference signal used for channel estimation of the radio propagation path into the subcarrier at the position calculated by the calculation unit, and transmits the reference signal to the terminal device.

According to one embodiment, it is possible to suppress a decrease in communication quality of a block that receives interference even in a situation where the block receives interference in F-OFDM.

FIG. 1 is a diagram illustrating an example of a communication system according to the first embodiment. FIG. 2 is a diagram for explaining an example of a block of a frequency band and a radio frame of each block used in the communication system according to the first embodiment. FIG. 3 is a diagram for explaining an example of a null point of out-of-band interference in the communication system according to the first embodiment. FIG. 4 is a diagram for explaining an example of an RS insertion position in the communication system according to the first embodiment. FIG. 5 is a diagram illustrating an example of the base station according to the first embodiment. FIG. 6 is a diagram illustrating an example of the terminal device according to the first embodiment. FIG. 7 is a diagram illustrating an example of hardware of the base station according to the first embodiment. FIG. 8 is a diagram illustrating an example of hardware of the terminal device according to the first embodiment. FIG. 9 is a flowchart illustrating an example of a processing procedure of the base station according to the first embodiment. FIG. 10 is a flowchart illustrating an example of a processing procedure of the terminal device according to the first embodiment. FIG. 11 is a schematic diagram illustrating an example of an RS insertion position in the communication system according to the second embodiment. FIG. 12 is a schematic diagram illustrating an example of an RS insertion position in the communication system according to the third embodiment. FIG. 13 is a diagram for explaining an example of frequency band allocation to each block in the communication system according to the fourth embodiment. FIG. 14 is a diagram for explaining an example of out-of-band interference from DL to UL in the base station according to the fifth embodiment. FIG. 15 is a diagram for explaining an example of time synchronization of rising edges of OFDM symbols of DL and UL blocks in the communication system according to the fifth embodiment. FIG. 16 is a schematic diagram illustrating an example of an RS insertion position in the communication system according to the fifth embodiment. FIG. 17 is a diagram illustrating an example of a base station according to the fifth embodiment. FIG. 18 is a diagram illustrating an example of a terminal device according to the fifth embodiment. FIG. 19 is a flowchart illustrating an example of a processing procedure of the base station according to the fifth embodiment. FIG. 20 is a flowchart illustrating an example of a processing procedure of the terminal device according to the fifth embodiment. FIG. 21 is a diagram for explaining an example of an RS insertion position in the communication system according to the sixth embodiment. FIG. 22 is a schematic diagram illustrating an example of an RS insertion position in the communication system according to the seventh embodiment. FIG. 23 is a diagram for explaining an example of frequency band allocation to each block in the communication system according to the eighth embodiment. FIG. 24 is a diagram illustrating an example of the base station according to the ninth embodiment. FIG. 25 is a diagram illustrating an example of the terminal device according to the ninth embodiment. FIG. 26 is a diagram illustrating an example of received power in the communication system and the base station according to the tenth embodiment. FIG. 27 is a diagram for explaining an example of out-of-band interference in the communication system according to the tenth embodiment. FIG. 28 is a schematic diagram illustrating an example of an RS insertion position in the communication system according to the tenth embodiment. FIG. 29 is a diagram illustrating an example of a base station according to the tenth embodiment. FIG. 30 is a diagram illustrating an example of the terminal device according to the tenth embodiment. FIG. 31 is a flowchart illustrating an example of a processing procedure of the base station according to the tenth embodiment. FIG. 32 is a flowchart illustrating an example of a processing procedure of the terminal device according to the tenth embodiment.

Hereinafter, embodiments of a base station, a terminal device, a communication system, and a communication method disclosed in the present application will be described with reference to the drawings. The following examples do not limit the disclosed technology. In addition, the embodiments can be appropriately combined within a range in which processing contents are not contradictory.

First, an outline of the communication system 1 according to the first embodiment will be described. FIG. 1 is a diagram illustrating an example of a communication system according to the first embodiment. FIG. 2 is a diagram for explaining an example of a block of a frequency band and a radio frame of each block used in the communication system according to the first embodiment. FIG. 3 is a diagram for explaining an example of a null point of out-of-band interference in the communication system according to the first embodiment. FIG. 4 is a diagram for explaining an example of an RS insertion position in the communication system according to the first embodiment.

The communication system 1 includes a terminal device 10 and a base station 20, for example, as shown in FIG. The terminal device 10 is connected to the base station 20 by wireless communication, and communicates with other devices via the base station 20. The base station 20 relays wireless communication of the terminal device 10. For example, the base station 20 transfers data received from the terminal device 10 by wireless communication to the counterpart device via the core network, and transfers data addressed to the terminal device 10 received from the core network to the terminal device 10 by wireless communication. To do.

In the following description, communication from the terminal device 10 to the base station 20 is referred to as UL (UpLink), and communication from the base station 20 to the terminal device 10 is referred to as DL (DownLink).

Here, in the communication system 1, for example, as shown in FIG. 2A, OFDM signals having different settings are divided into a plurality of blocks # 1, # 2, and # 3 having different frequency bands, and one carrier (carrier wave) is obtained. ). That is, in the communication system 1, different OFDM signals are filtered for each block of a plurality of frequency bands and transmitted using one carrier. Here, each block can be used for different communication applications. If the application of communication is different, there may be a difference in the transmission power of each block as shown in FIG. FIG. 2A illustrates a DL block. For example, as shown in FIG. 2, when there is a difference in the transmission power of each block, out-of-band interference from a block with high transmission power (for example, block # 1) to a block with low transmission power (for example, block # 2) May occur.

Here, in the FFT (Fast Fourier Transform) section of the OFDM symbol of interest, if the relationship of other OFDM symbol lengths is 1 / n (n is an integer), the OFDM symbol of interest is There is a characteristic that interference from an OFDM symbol becomes null.

For example, as shown in FIG. 2B, in the FFT interval of block # 2, the OFDM symbol length of block # 1 is set to have a 1/4 relationship with the OFDM symbol length of block # 2. That is, the entire symbol of block # 1 is set to fit in the FFT interval of block # 2. Thus, for example, as shown in FIG. 3, in block # 2, a location where the out-of-band interference from block # 1 is null (null point) is included for every four subcarriers.

Therefore, in the communication system 1, taking advantage of such characteristics, in order to suppress deterioration in communication quality of a block that receives interference (for example, block # 2 shown in FIGS. 2 and 3), the RS (Reference Signal) is used in the block. ) Is inserted at the position of the null point. This is because information important in decoding a signal used for communication in the communication system 1 is channel information of a radio propagation path. RS is an example of a reference signal used for channel estimation of a radio propagation path.

In the communication system 1 according to the present embodiment, for example, as illustrated in FIG. 4, among the subcarriers of a block (for example, block # 2) that receives interference from an adjacent block (for example, block # 1), the interference is a null point. RS is inserted into the subcarrier at the position.

Note that information (hereinafter referred to as RS information) indicating the position of the subcarrier in which the RS of the block that receives interference is inserted is, for example, because the base station 20 receives F-OFDM. Is notified to the terminal device 10 together with the filtering information. The filtering information includes the frequency band of each block, the center frequency of each block, and the OFDM symbol length of each block. For this notification, a channel not subjected to F-OFDM filtering is used. Thereby, the terminal device 10 can acquire the information of RS of the block reliably.

According to the communication system 1 described above, since it is possible to suppress a decrease in the estimation accuracy of the radio propagation path even in a block receiving out-of-band interference from other blocks, it is possible to improve the decoding accuracy of the received signal. it can. As a result, the communication system 1 can suppress a decrease in communication quality of a block that receives interference even in a situation where the block receives interference in F-OFDM.

(base station)
Next, an example of the base station 20 will be described with reference to FIG. FIG. 5 is a diagram illustrating an example of the base station according to the first embodiment. The base station 20 includes an antenna, an RF receiving unit 210, an RF transmitting unit 211, an oscillator, a block setting unit 220, an UL F-OFDM unit 221, an UL signal processing unit 222, a radio control signal processing unit 223, and a DL signal processing unit. 224. The base station 20 includes a DL F-OFDM unit 225, a radio scheduler unit 226, a DL RS insertion calculation unit 227, and an IP (Internet Protocol) processing unit 230. The block setting unit 220 is an example of a setting unit, the DL signal processing unit 224 is an example of a signal processing unit, the DL F-OFDM unit 225 is an example of a filtering unit, and the DL RS insertion calculation unit 227 calculates It is an example of a part. In FIG. 5, two oscillators are shown, but these oscillators generate a carrier wave having a common frequency. Therefore, one oscillator may be provided in common for the RF reception unit 210 and the RF transmission unit 211.

In the base station 20 illustrated in FIG. 5, one DL signal processing unit 224 and one DL F-OFDM unit 225 are provided for each block of DL signals to be filtered. Further, in the base station 20 illustrated in FIG. 5, one UL F-OFDM unit 221 and one UL signal processing unit 222 are provided for each block of the UL signal to be filtered.

The antenna transmits and receives radio signals to and from the terminal device 10. For example, the antenna outputs a radio signal received from the terminal device 10 to the RF reception unit 210 and transmits a radio signal output from the RF transmission unit 211 to the terminal device 10.

The RF receiver 210 receives a radio signal transmitted from the terminal device 10 via an antenna. Hereinafter, a radio signal transmitted from the terminal apparatus 10 to the base station 20 is referred to as a UL signal, and a radio signal transmitted from the base station 20 to the terminal apparatus 10 is referred to as a DL signal. The RF receiving unit 210 down-converts the UL signal received from the terminal device 10 via the antenna using the local signal generated by the oscillator. Then, the RF receiving unit 210 converts the down-converted UL signal into a digital signal and outputs the digital signal to the UL F-OFDM unit 221.

The block setting unit 220 includes filtering information including setting information indicating which communication (for example, V2X communication, IoT communication) uses which frequency band among a plurality of different frequency band blocks generated for one carrier. Keep information. Then, the block setting unit 220 sets filtering for the UL F-OFDM unit 221 and the DL F-OFDM unit 225 using the filtering information. This filtering information is notified to the terminal device 10 by the radio control signal processing unit 223, for example.

Further, the block setting unit 220 notifies the DL RS insertion calculation unit 227 of the filtering information, and the DL RS insertion calculation unit 227 provides sub-carriers in which interference from adjacent blocks becomes a null point for each block. RS information indicating the position of is received. Then, the block setting unit 220 notifies the radio control signal processing unit 223 of the received RS information of each block and filtering information of each block.

The UL F-OFDM unit 221 performs filtering processing on the block of the UL signal and outputs the filtered signal to the UL signal processing unit 222. For example, the UL F-OFDM unit 221 performs filtering on the F-OFDM in units of blocks using the filter set by the block setting unit 220 and outputs the result to the UL signal processing unit 222.

Based on the filtering information output from the block setting unit 220, the DL RS insertion calculation unit 227 calculates RS information indicating the position of the subcarrier into which the RS is inserted among the subcarriers of the block that receives out-of-band interference. . Hereinafter, the position of the subcarrier into which the RS is inserted may be referred to as a subcarrier position.

For example, when a plurality of blocks are included in the DL, the DL RS insertion calculation unit 227 considers out-of-band interference from a block having a subcarrier to which high power is allocated to an adjacent block, and causes interference in the adjacent block. Is calculated as a null point.

For example, the DL RS insertion calculation unit 227 calculates the subcarrier position of the block # 2 where the interference from the block # 1 to the block # 2 illustrated in FIG. Then, the DL RS insertion calculation unit 227 notifies the DL signal processing unit 224 of the corresponding block (for example, block # 2) as the RS information of the subcarrier position where the calculated interference is a null point. That is, the DL RS insertion calculation unit 227 notifies the DL signal processing unit 224 of the subcarrier position into which RS is inserted in the block that receives out-of-band interference as RS information.

The DL signal processing unit 224 performs various processes related to the DL signal. For example, the DL signal processing unit 224 divides and combines a UL feedback signal or a DL IP packet into a transmittable size, and generates an encoded digital signal. Also, the DL signal processing unit 224 receives the RS information from the DL RS insertion calculation unit 227, and inserts the RS into the DL subcarrier at the position indicated by the RS information. Then, the DL signal processing unit 224 outputs the DL signal into which the RS is inserted to the DL F-OFDM unit 225.

The UL signal processing unit 222 performs various processes related to the UL signal. For example, the UL signal processing unit 222 demodulates and decodes the digital signal after the filtering process, and outputs the demodulated signal to the IP processing unit 230.

The radio control signal processing unit 223 generates a radio control signal. For example, the radio control signal processing unit 223 generates an ACK response when the UL signal is correctly decoded by the UL signal processing unit 222, and generates a NACK response when the UL signal is not correctly decoded. Then, the radio control signal processing unit 223 outputs the generated response to the DL signal processing unit 224 as a feedback signal of the UL signal. Further, the radio control signal processing unit 223 transmits the RS information and filtering information notified by the block setting unit 220 and the DL signal processing unit 224 to the terminal device 10. In the present embodiment, the RS information and the filtering information are included in the broadcast information transmitted from the base station 20 to the terminal device 10.

The wireless scheduler unit 226 schedules wireless communication with the terminal device 10. Specifically, the radio scheduler unit 226 collects SINR estimation information of a signal via the DL from the DL feedback signal received by the UL signal processing unit 222. The radio scheduler unit 226 also collects UL SINR estimation information received by the UL signal processing unit 222. Then, the radio scheduler unit 226 calculates the amount of data per unit time that can be transmitted via the radio propagation path with the terminal device 10 using the collected DL and UL SINR estimation information. Thereafter, the wireless scheduler unit 226 controls the data amount transmitted per unit time in the DL signal processing unit 224 using the calculated data amount per unit time. In addition, the wireless scheduler unit 226 notifies the terminal device 10 of wireless communication schedule information, and controls the amount of data transmitted per unit time on the terminal device 10 side.

The IP processing unit 230 processes IP packets. For example, the IP processing unit 230 constructs an IP packet from the UL signal output from the UL signal processing unit 222, and outputs the constructed IP packet to the core network. Further, when receiving the IP packet output from the core network, the IP processing unit 230 outputs the IP packet to the DL signal processing unit 224 of the block corresponding to the data type of the IP packet.

The DL signal processing unit 224 performs various processes related to the DL signal. For example, the DL signal processing unit 224 generates a DL signal by dividing and combining a UL feedback signal or DL IP packet received from the terminal device 10 into a transmittable size, and performing encoding and modulation. . Then, the DL signal processing unit 224 outputs the generated DL signal to the DL F-OFDM unit 225.

The DL F-OFDM unit 225 performs a filtering process for each block of the DL signal and outputs it to the RF transmission unit 211. For example, the DL F-OFDM unit 225 filters the DL signal in units of blocks using the filter set by the block setting unit 220, and outputs the DL signal to the RF transmission unit 211.

The RF transmission unit 211 wirelessly transmits a DL signal to the terminal device 10 via the antenna. The RF transmission unit 211 is connected to an oscillator, and the DL signal output from the DL F-OFDM unit 225 is converted into an analog signal, and then up-converted by a local signal generated by the oscillator. Via the terminal device 10. The oscillator generates a local oscillation signal having the same frequency as the carrier of the DL signal to be transmitted.

(Terminal device)
Next, an example of the terminal device 10 will be described with reference to FIG. FIG. 6 is a diagram illustrating an example of the terminal device according to the first embodiment. The terminal device 10 is realized by, for example, a mobile phone, a smartphone, a personal computer, or the like.

The terminal device 10 includes an antenna, an RF receiver 110, an RF transmitter 111, and an oscillator. Also, the terminal device 10 includes a block receiving unit 120, a DL F-OFDM unit 121, a DL signal processing unit 122, a radio control signal processing unit 123, a UL signal processing unit 124, a UL F-OFDM unit 125, and a DL An RS information receiving unit 126 is provided. In addition, the terminal device 10 includes an application processing unit 131 and an IP processing unit 130. The DL signal processing unit 122 is an example of a signal processing unit, and the DL RS information receiving unit 126 is an example of a receiving unit.

In the terminal device 10 illustrated in FIG. 6, one DL F-OFDM unit 121 and one DL signal processing unit 122 are provided for each block of the DL signal to be filtered. Further, in the terminal device 10 illustrated in FIG. 6, one UL signal processing unit 124 and one UL F-OFDM unit 125 are provided for each block of the UL signal to be filtered.

The antenna transmits and receives radio signals to and from the base station 20. For example, the antenna outputs a DL signal received from the base station 20 to the RF reception unit 110 and outputs a UL signal output from the RF transmission unit 111 to the base station 20.

The RF receiving unit 110 receives the DL signal transmitted from the base station 20. The RF receiving unit 110 is connected to an oscillator, and down-converts the received DL signal using a local signal generated by the oscillator. Then, RF receiving section 110 converts the down-converted DL signal into a digital signal and outputs the digital signal to DL F-OFDM section 121.

The radio control signal processing unit 123 generates a radio control signal. For example, the radio control signal processing unit 123 generates an ACK response when the DL signal is correctly decoded by the DL signal processing unit 122, and generates a NACK response when the DL signal is not correctly decoded. Then, the radio control signal processing unit 123 outputs the generated response to the UL signal processing unit 124 as a DL signal feedback signal.

Also, the radio control signal processing unit 123 acquires filtering information and RS information of each block from the broadcast information received via the DL signal processing unit 122. Then, radio control signal processing section 123 notifies filtering information to block receiving section 120 and notifies RS information to DL RS information receiving section 126.

Furthermore, the radio control signal processing unit 123 collects the SINR estimation information of the DL signal received from the DL signal processing unit 122 and outputs it to the UL signal processing unit 124 as a feedback signal.

The block receiving unit 120 receives the filtering information of each block notified from the radio control signal processing unit 123. Then, the block receiving unit 120 sets filtering for the DL F-OFDM unit 121 and the UL F-OFDM unit 125 using the filtering information.

The DL F-OFDM unit 121 performs a filtering process for each block of the DL signal and outputs the result to the DL signal processing unit 122. For example, the DL F-OFDM unit 121 performs filtering on the block basis for F-OFDM using the filter set by the block receiving unit 120, and outputs the result to the DL signal processing unit 122.

The DL RS information receiving unit 126 notifies the DL signal processing unit 122 of the RS information notified from the radio control signal processing unit 123.

The DL signal processing unit 122 performs various processes related to the DL signal. For example, the DL signal processing unit 122 receives the RS inserted in the subcarrier at the position indicated by the RS information notified from the DL RS information receiving unit 126. Then, the DL signal processing unit 122 estimates the channel of the radio propagation path between the base station 20 and the terminal device 10 based on the received RS, and assigns it to other subcarriers using the estimated channel information. The received signal is demodulated and decoded. Then, the DL signal processing unit 122 outputs the decoded DL signal to the IP processing unit 130.

The application processing unit 131 executes various processes using an application program. For example, the application processing unit 131 outputs the application data to the UL signal processing unit 124 via the IP processing unit 130 when application data for the communication partner device of the terminal device 10 is generated. In addition, the application processing unit 131 executes various processes on the data received from the DL signal processing unit 122 via the IP processing unit 130.

The IP processing unit 130 processes IP packets. For example, the IP processing unit 130 constructs an IP packet from the DL signal output from the DL signal processing unit 122 and outputs the constructed IP packet to the application processing unit 131 as application data. In addition, the IP processing unit 130 outputs the IP packet of the application data output from the application processing unit 131 to the UL signal processing unit 124 of the block corresponding to the data type of the application data.

The UL signal processing unit 124 performs various processes related to the UL signal. For example, the UL signal processing unit 124 divides and combines IP packets into sizes that can be transmitted based on information notified from the radio scheduler unit 226 of the base station 20, and performs encoding, modulation, etc. Is generated. Then, the UL signal processing unit 124 outputs the generated UL signal to the UL F-OFDM unit 125.

The UL F-OFDM unit 125 performs filtering on the block of the UL signal and outputs the filtered block to the RF transmission unit 111. For example, the UL F-OFDM unit 125 filters the UL signal in units of blocks using the filter set by the block reception unit 120 and outputs the filtered UL signal to the RF transmission unit 111.

The RF transmitter 111 wirelessly transmits a UL signal to the base station 20 via the antenna. The RF transmitter 111 is connected to an oscillator, and the UL signal output from the DL F-OFDM unit 121 is converted into an analog signal, and then up-converted by a local signal generated by the oscillator, Is transmitted to the base station 20 via the network. The oscillator generates a local oscillation signal having the same frequency as the carrier of the UL signal to be transmitted.

According to the communication system 1 described above, it is possible to suppress a decrease in communication quality of a block that receives interference even in a situation where the block receives interference in F-OFDM.

(hardware)
Next, the hardware of the base station 20 will be described with reference to FIG. FIG. 7 is a diagram illustrating an example of hardware of the base station according to the first embodiment. The base station 20 is realized by a device including an antenna, an RF module 21, a DSP (Digital Signal Processor) 22, an NWP (NetWork Processor) 23, and a memory 24, for example.

The RF module 21 is a module including, for example, the oscillator, the RF transmission unit 211, and the RF reception unit 210 illustrated in FIG. The DSP 22 includes, for example, the block setting unit 220, the UL F-OFDM unit 221, the UL signal processing unit 222, the radio control signal processing unit 223, the DL signal processing unit 224, the DL F-OFDM unit 225, and the like illustrated in FIG. A chip including a wireless scheduler unit 226. The NWP 23 is a chip including the IP processing unit 230 illustrated in FIG. 5, for example. The memory 24 stores filtering information, RS information, and the like. In addition, the memory 24 temporarily holds packets after IP in DL communication. Then, after the DSP 22 transmits a packet, when it is confirmed that ACK is received for the packet, the memory 24 erases the temporarily held packet from the memory 24. The memory 24 temporarily holds a UL signal in UL communication. When the NWP 23 transmits an IP packet constructed from the UL signal to the core network and receives the TCP ACK of the packet, the memory 24 erases the temporarily retained UL signal from the memory 24.

Next, an example of the hardware of the terminal device 10 will be described with reference to FIG. FIG. 8 is a diagram illustrating an example of hardware of the terminal device according to the first embodiment. The terminal device 10 is realized by a device including an antenna, an RF module 11, a DSP 12, a MPU (Micro Processing Unit) 13, and a memory 14, for example.

The RF module 11 is a module including, for example, the oscillator, the RF receiving unit 110, and the RF transmitting unit 111 illustrated in FIG. The DSP 12 is a chip including, for example, the DL F-OFDM unit 121, the DL signal processing unit 122, the radio control signal processing unit 123, the UL signal processing unit 124, and the UL F-OFDM unit 125 illustrated in FIG. The MPU 13 is a chip including, for example, the IP processing unit 130 and the application processing unit 131 illustrated in FIG. The memory 14 stores filtering information, RS information, data handled by the application processing unit 131, and the like.

Note that the terminal devices and base station hardware included in the communication system 1 according to the second to tenth embodiments described below are the same as the terminal device and base station hardware included in the communication system 1 according to the first embodiment. Is omitted.

(Processing procedure)
Next, the processing procedure of the base station 20 will be described with reference to FIG. FIG. 9 is a flowchart illustrating an example of a processing procedure of the base station according to the first embodiment. The base station 20 determines a DL F-OFDM block and its filter (S1), and calculates a DL RS insertion interval (S2). That is, in step S1, the base station 20 determines DL F-OFDM blocks and filtering information indicating the filters. Then, the DL RS insertion calculation unit 227 calculates RS information indicating the subcarrier position where the RS is inserted in the block that receives out-of-band interference based on the filtering information determined in step S1.

Then, the base station 20 notifies the terminal device 10 of DL filtering information and DL RS information (S3). That is, the block setting unit 220 of the base station 20 notifies the DL F-OFDM filtering information determined in step S1 to the DL F-OFDM unit 225. Also, the DL RS insertion calculation unit 227 of the base station 20 notifies the DL signal processing unit 224 of the DL RS information determined in step S2. Accordingly, broadcast information including DL filtering information and RS information is transmitted to the terminal device 10.

After step S3, the base station 20 applies filtering information and RS information (S4), and transmits DL data (S5). That is, the DL signal processing unit 224 of each block of the base station 20 inserts an RS into the DL subcarrier at the position indicated by the DL RS information notified in step S3. Then, the DL signal processing unit 224 outputs the DL signal after the RS insertion to the DL F-OFDM unit 225 that performs filtering of the corresponding block. The DL F-OFDM unit 225 of each block applies a filter based on the DL filtering information notified in step S3. Then, the DL F-OFDM unit 225 performs a filtering process on the DL signal output from the DL signal processing unit 224. Thereafter, the RF transmission unit 211 transmits the DL signal after the filtering process to the terminal device 10.

Next, the processing procedure of the terminal device 10 will be described with reference to FIG. FIG. 10 is a flowchart illustrating an example of a processing procedure of the terminal device according to the first embodiment. The terminal device 10 receives broadcast information from the base station 20 (S11). That is, the DL signal processing unit 122 of the terminal device 10 receives broadcast information from the base station 20.

After step S11, the terminal device 10 extracts DL filtering information and DL RS information from the broadcast information received in step S11 (S12). That is, the radio control signal processing unit 123 of the terminal device 10 extracts DL filtering information and RS information of each block from the broadcast information received by the DL signal processing unit 122.

After step S12, the terminal device 10 applies filtering information and RS information (S13), and receives DL data (S14).

That is, the block receiving unit 120 of the terminal device 10 notifies the DL F-OFDM unit 121 of the DL filtering information extracted in step S12. Based on the notified filtering information, the DL F-OFDM unit 121 performs a filtering process on the DL signal received by the RF receiving unit 110 and outputs the filtered signal to the DL signal processing unit 122. Also, the DL RS information receiving unit 126 of the terminal device 10 notifies the DL signal processing unit 122 of the DL RS information extracted in step S12. The DL signal processing unit 122 receives the RS inserted in the subcarrier at the position indicated by the RS information notified from the DL RS information receiving unit 126. Then, the DL signal processing unit 122 estimates the channel of the radio propagation path between the base station 20 and the terminal device 10 based on the received RS, and assigns it to other subcarriers using the estimated channel information. The received DL data is demodulated.

(Effect of Example 1)
According to the communication system 1 of the first embodiment, the terminal apparatus 10 can acquire the RS of the block that receives the interference even in a situation where the block receives interference in F-OFDM. Thereby, the communication system 1 of a present Example can improve the estimation precision of the channel of a radio propagation path. Thereby, the communication system 1 of a present Example can improve the decoding precision of a received signal. As a result, the communication system 1 can suppress a decrease in communication quality of a block that receives interference even in a situation where the block receives interference in F-OFDM.

FIG. 11 is a diagram for explaining an example of an RS insertion position in the communication system according to the second embodiment. For example, as illustrated in FIG. 11, the DL RS insertion calculation unit 227 of the base station 20 according to the second embodiment performs subcarriers at positions that are integer multiples of the null point of interference from adjacent blocks in the DL signal on the frequency axis. Is the RS insertion position. Note that RSs may not be inserted in all subcarriers at positions that are integer multiples of the null point of interference from adjacent blocks in the DL signal on the frequency axis. The RS is preferably inserted into, for example, about 15 to 20% of subcarriers included in the block of the DL signal.

(Effect of Example 2)
According to the communication system 1 of the second embodiment, the base station 20 can avoid excessive insertion of RSs in the DL signal, and thus can suppress a decrease in the data communication speed of the DL signal.

FIG. 12 is a diagram for explaining an example of an RS insertion position in the communication system according to the third embodiment. For example, as illustrated in FIG. 12, the DL RS insertion calculation unit 227 of the base station 20 according to the third embodiment inserts RSs into subcarriers arranged at the null points of interference from adjacent blocks in the DL signal. At this time, DL RS insertion calculation section 227 sets the power of subcarriers arranged at the null point of interference from adjacent blocks in the DL signal to be lower than the power of other subcarriers.

On the other hand, the DL RS insertion calculation unit 227 increases the power of the subcarrier at the peak point of interference from the adjacent block by the amount by which the power of the subcarrier arranged at the null point is decreased. The interference signal from the adjacent block has a peak at, for example, an intermediate position between adjacent null points on the frequency axis. For this reason, the DL RS insertion calculation unit 227 according to the present embodiment increases the power of subcarriers arranged at a position intermediate between adjacent null points. As a result, the subcarrier into which the RS is inserted at the interference null point is assigned with power that allows channel estimation of the radio propagation path, and the remaining power is assigned to the subcarrier with strong interference.

(Effect of Example 3)
According to the communication system 1 of the third embodiment, it is possible to improve the estimation accuracy of the channel of the radio propagation path and further improve the decoding accuracy of the received signal even when the DL signal receives interference from adjacent blocks. be able to.

FIG. 13 is a diagram for explaining an example of frequency band allocation to each block in the communication system according to the fourth embodiment. The block setting unit 220 of the base station 20 according to the fourth embodiment determines the center frequency of the frequency band assigned to the block according to the OFDM symbol length of each block.

For example, as shown in FIG. 13, consider a case where three blocks # 1, # 2, and # 3 are allocated within a 20 MHz frequency band. Here, it is assumed that the OFDM symbol length of block # 3 is longer than the OFDM symbol length of block # 2. Also, it is assumed that the OFDM symbol length of block # 2 is longer than the OFDM symbol length of block # 1.

In this case, the block setting unit 220 of the base station 20 assigns a block having a short OFDM symbol length from the lowest frequency band in the transmission band. In this manner, the OFDM symbols are sequentially assigned in ascending order of the OFDM symbol length from the lowest frequency band. In the present embodiment, the block setting unit 220 assigns frequency bands in the order of block # 1 → block # 2 → block # 3 from a low frequency band, for example, as shown in FIG.

(Effect of Example 4)
According to the communication system 1 of the fourth embodiment, a block having a short OFDM symbol length and in which interference in subcarrier units is difficult to avoid is arranged away from other blocks that cause interference, so that interference received from other blocks is reduced. The impact can be reduced.

In the first to fourth embodiments described above, a case where a block with low transmission power receives interference from a block with high transmission power due to a difference in transmission power of each block divided by filtering an OFDM signal in DL. Explained in the example. Here, it is conceivable that each block divided by filtering the OFDM signal is assigned to UL or DL for each block, and multiplexed communication of UL and DL is performed. In this case, when viewed at the antenna end of the base station 20, the power of the block allocated to the DL is much larger than the power of the block allocated to the UL. For this reason, it is conceivable that the signal of the block assigned to DL becomes interference of the signal of the block assigned to UL.

This will be described with reference to FIG. FIG. 14 is a diagram for explaining an example of out-of-band interference from DL to UL in the base station according to the fifth embodiment. For example, the power per subcarrier at the antenna end of the base station is greater in the DL block than in the UL block. That is, since the UL block received by the base station is received via the radio propagation path, the power is small. On the other hand, the DL block transmitted from the base station has high power because it is transmitted with power including propagation loss so that the terminal device 10 receives the DL block with predetermined power via the radio propagation path.

In the FDD (Frequency Division Duplex), interference caused by the power difference between UL and DL in such a base station is caused by the base station placing UL and DL on different frequency carriers and separating them by RF filters in the RF receiver. Avoided. Also, in TDD (Time Division Duplex), the base station switches the transmission / reception circuit at the switching timing of UL and DL, so there is no problem.

However, in the case where UL and DL are always multiplexed on one carrier, it is difficult to use either method. In a case where UL and DL are always multiplexed on one carrier, for example, as shown in FIG. 14, UL and DL are separated using a circulator that separates in the traveling direction of electromagnetic waves. However, the separation performance of the circulator is not absolute. For example, as indicated by an arrow 1401 in FIG. 14, the DL signal transmitted from the RF transmitter of the base station is a predetermined amount toward the RF receiver. It may leak. For this reason, for example, when DL and UL communication occur at the same time, the RF receiving unit may have a higher power per subcarrier in the leakage block from the DL than in the UL block. As a result, for example, as shown in a balloon 1402 in FIG. 14, out-of-band interference from the DL block leaks to the UL block band, and the UL communication quality may be degraded.

Therefore, even when UL or DL is assigned to each F-OFDM block and UL and DL multiplex communication is performed, by performing the RS insertion method described in the first to fourth embodiments, in the base station, A decrease in UL communication quality can be suppressed.

In addition, as described in the first to fourth embodiments, in order to insert an RS into a subcarrier at a null point of interference from another block, time synchronization of the rising edge of the OFDM symbol of each block may be taken. is important. This will be described with reference to FIGS. 15 and 16. FIG. 15 is a diagram for explaining an example of time synchronization of rising edges of OFDM symbols of DL and UL blocks in the communication system according to the fifth embodiment. FIG. 16 is a schematic diagram illustrating an example of an RS insertion position in the communication system according to the fifth embodiment.

Here, for example, as shown in FIG. 15A, the DL # 1 and DL # 2 blocks and the UL # 1 and UL # 2 blocks are used, and the power difference between the DL block and the UL block is determined. Consider a case where interference to a UL block occurs. In this case, for example, as shown in FIG. 15B, if the time synchronization of the rising edge of the OFDM symbol is not established between the DL and UL blocks, the DL FFT symbol section is included in the UL FFT section for out-of-band interference. I can't. As a result, when FFT is performed at the UL OFDM symbol timing, no null point appears in the frequency component outside the DL band.

Therefore, in the communication system 1 according to the present embodiment, for example, as shown in FIG. 15C, the rise times of the OFDM symbols of the respective blocks of DL and UL are synchronized. Thereby, for example, in the FFT interval of UL # 2, the relationship between the OFDM symbol of interest and the length of other OFDM symbols is 1 / n. Therefore, in the communication system 1, it is possible to insert an RS at a null point of interference from other OFDM symbols.

For example, in FIG. 15, there is one null point for every 4 subcarriers from the block of DL # 1 for the subcarrier on the frequency axis of the OFDM symbol of interest. In the DL # 2 block, all subcarriers have null points on the frequency axis. Considering these, no interference from the DL with high power per subcarrier enters the null point of interference from the block of DL # 1. Therefore, in the communication system 1, for example, as shown in FIG. 16, the RSs of the UL # 1 and # 2 blocks are inserted at the null points of interference from the DL # 1 block. Thereby, in the communication system 1, the degradation of the communication quality of UL # 1 and # 2 that receives interference from DL # 1 and # 2 can be suppressed.

(base station)
Next, an example of the base station 20a in the communication system according to the fifth embodiment will be described with reference to FIG. FIG. 17 is a diagram illustrating an example of a base station according to the fifth embodiment. Except for the points described below, in FIG. 17, blocks denoted by the same reference numerals as those in FIG. 5 have the same or similar functions as the blocks in FIG.

The base station 20a includes a circulator and a synchronization unit 228. Further, the base station 20 a includes a UL RS insertion calculation unit 229 instead of the DL RS insertion calculation unit 227.

The circulator separates UL and DL in the traveling direction of the electromagnetic wave, outputs the UL signal output from the antenna to the RF reception unit 210, and outputs the DL signal output from the RF transmission unit 211 to the antenna.

The synchronization unit 228 synchronizes the rising edge of the OFDM symbol of each block. That is, when the synchronization unit 228 acquires the UL signal reception time from the UL signal processing unit 222, the synchronization unit 228 detects a difference from the rise time of the OFDM symbol in the DL signal processing. Then, the synchronization unit 228 generates TA (Timing Advance) information so as to fill the detected difference, and outputs the TA (Timing Advance) information to the radio control signal processing unit 223. The radio control signal processing unit 223 converts the TA information output from the synchronization unit 228 into an appropriate information element and notifies the DL signal processing unit 224 of the TA information. The DL signal processing unit 224 transmits the information converted by the radio control signal processing unit 223 to the terminal device 10a as a feedback signal from the base station 20a.

The UL RS insertion calculation unit 229 performs UL subcarrier position at which interference from the DL block becomes a null point for out-of-band interference leaking from the block included in the DL signal to the UL block band based on the filtering information. Is calculated. Then, the UL RS insertion calculation unit 229 notifies the UL signal processing unit 222 of each block as the RS information of the subcarrier position where the calculated interference is a null point. Also, the UL RS insertion calculation unit 229 notifies the block setting unit 220 of the RS information. The block setting unit 220 notifies the radio control signal processing unit 223 of RS information for each block of UL in addition to filtering information for each block. Then, the radio control signal processing unit 223 transmits broadcast information including filtering information for each block and RS information for each block of the UL to the terminal device 10a via the DL signal processing unit 224.

The UL signal processing unit 222 estimates the UL radio channel based on the RS information notified from the UL RS insertion calculation unit 229, and performs demodulation of the UL signal based on the estimated channel information. Do.

(Terminal device)
Next, an example of the terminal device 10a in the communication system 1 according to the fifth embodiment will be described with reference to FIG. FIG. 18 is a diagram illustrating an example of a terminal device according to the fifth embodiment. Except for the points described below, in FIG. 18, blocks denoted by the same reference numerals as those in FIG. 6 have the same or similar functions as the blocks in FIG.

The terminal device 10a includes a circulator, a TA receiving unit 128, and a delay unit 129. Further, the terminal device 10 a includes a UL RS information receiving unit 127 instead of the DL RS information receiving unit 126.

The circulator separates UL and DL in the traveling direction of the electromagnetic wave, outputs the DL signal output from the antenna to the RF receiving unit 110, and outputs the UL signal output from the RF transmitting unit 111 to the antenna.

The TA receiver 128 receives the TA information notified from the base station 20a via the DL signal processor 122 and the radio control signal processor 123. Then, the TA receiving unit 128 notifies the delay unit 129 of the time offset value notified by the TA information.

The delay unit 129 delays the timing of the UL signal output from the UL signal processing unit 124 based on the time offset value notified by the TA receiving unit 128 and outputs the UL signal to the UL F-OFDM unit 125.

When receiving RS information for each block of UL included in the broadcast information received by the radio control signal processing unit 123, the UL RS information receiving unit 127 notifies the UL signal processing unit 124 of the received RS information. The UL signal processing unit 124 inserts the RS into the UL subcarrier at the position indicated by the RS information notified from the UL RS information receiving unit 127, and transmits it via the Delay unit 129 and the UL F-OFDM unit 125. To do.

According to the communication system 1 described above, the base station 20a determines the UL RS from the signal received from the terminal device 10a even if the UL receives interference from the DL due to the multiplex communication of DL and UL. Can be acquired. Thereby, in the communication system 1, since the decoding accuracy of UL can be improved when performing multiplex communication of DL and UL using one carrier, it is possible to suppress a decrease in UL communication quality.

Further, in the communication system 1, when there is a difference in the rise time of the OFDM symbol of each block of DL and UL, synchronization is taken at the antenna end of the base station 20 so as to fill this difference. Thereby, since the base station 20 can acquire the RS inserted in the UL subcarrier at the position of the null point of interference from the DL block, it suppresses the deterioration of the communication quality of the UL block. Can do.

In addition, transmission and reception of UL data in the communication system 1 according to the fifth embodiment are performed, for example, according to processing procedures illustrated in FIGS. 19 and 20 below. FIG. 19 is a flowchart illustrating an example of a processing procedure of the base station according to the fifth embodiment. FIG. 20 is a flowchart illustrating an example of a processing procedure of the terminal device according to the fifth embodiment. First, the processing procedure of the base station 20a will be described with reference to FIG.

The base station 20a determines DL and UL F-OFDM blocks and their filters (S21). That is, in step S21, the base station 20a determines filtering information indicating DL and UL F-OFDM blocks and their filters. The DL and UL filtering information determined in S21 is held in the block setting unit 220.

Next, the base station 20a calculates a UL RS insertion interval (S22). That is, the UL RS insertion calculation unit 229 of the base station 20a determines RS information indicating the subcarrier position into which the RS is inserted in the UL block, based on the DL and UL filtering information determined in step S21.

The base station 20a notifies UL filtering information and UL RS information (S23). That is, the block setting unit 220 of the base station 20a notifies the UL F-OFDM unit 221 of the DL and UL filtering information determined in step S21. Also, the UL RS insertion calculation unit 229 of the base station 20a notifies the UL signal processing unit 222 of the UL RS information determined in step S22. Further, the base station 20a transmits broadcast information including UL filtering information and UL RS information to the terminal device 10a.

Next, the base station 20a applies filtering information and UL RS information (S24), and receives UL data (S25). That is, the UL F-OFDM unit 221 of the base station 20a applies a filter to the UL signal output from the RF receiving unit 210 based on the UL filtering information notified in step S23. Then, the UL F-OFDM unit 221 outputs the filtered UL signal to the UL signal processing unit 222. The UL signal processing unit 222 estimates the UL radio propagation channel based on the UL RS information notified in step S23, and demodulates the UL signal based on the estimated channel information.

Next, the processing procedure of the terminal device 10a will be described with reference to FIG. First, the terminal device 10a receives broadcast information from the base station 20a (S31). That is, the DL signal processing unit 122 of the terminal device 10a receives broadcast information from the base station 20a.

Next, the terminal device 10a extracts UL filtering information and UL RS information from the broadcast information received in step S31 (S32). That is, the radio control signal processing unit 123 of the terminal device 10 a extracts UL filtering information and UL RS information of each block from the broadcast information received by the DL signal processing unit 122.

After step S32, the terminal device 10a applies UL filtering information and UL RS information (S33), and transmits UL data (S34). That is, the block receiving unit 120 of the terminal device 10a notifies the UL F-OFDM unit 125 of the UL filtering information extracted in step S32. Also, the UL RS information receiving unit 127 of the terminal device 10a notifies the UL signal processing unit 124 of the UL RS information extracted in step S32.

Then, the UL signal processing unit 124 inserts the RS into the UL subcarrier at the position indicated by the notified RS information, and outputs the RS to the Delay unit 129. The delay unit 129 delays the timing based on the time offset value notified from the TA receiving unit 128 and outputs the UL signal output from the UL signal processing unit 124 to the UL F-OFDM unit 125. The UL F-OFDM unit 125 performs filtering processing on the UL signal based on the filtering information notified from the block reception unit 120 and transmits the filtered UL signal to the base station 20 via the RF transmission unit 111.

(Effect of Example 5)
According to the communication system 1 of the fifth embodiment, the base station 20a uses the UL RS from the signal received from the terminal device 10a even if the UL receives interference from the DL due to the multiplex communication of DL and UL. Can be obtained. Thereby, in the communication system 1, since the decoding accuracy of UL can be improved when performing multiplex communication of DL and UL using one carrier, it is possible to suppress a decrease in UL communication quality.

FIG. 21 is a diagram for explaining an example of an RS insertion position in the communication system according to the sixth embodiment. For example, as illustrated in FIG. 21, the UL RS insertion calculation unit 229 of the base station 20 a according to the sixth embodiment uses an integer multiple of the null point of interference from a DL block on the frequency axis among UL subcarriers. The subcarrier at the position of (2) is the UL RS insertion position.

(Effect of Example 6)
According to the communication system 1 of the sixth embodiment, since the RS is not excessively inserted into the UL signal, it is possible to suppress a decrease in the data communication speed of the UL signal.

FIG. 22 is a diagram for explaining an example of an RS insertion position in the communication system according to the seventh embodiment. The UL signal processing unit 124 of the terminal device 10 according to the seventh embodiment inserts an RS into the UL subcarrier at the position indicated by the RS information. At this time, UL signal processing section 124 sets the power of subcarriers arranged at the null point of interference from the DL signal to be lower than the power of other subcarriers in the UL signal. On the other hand, the UL signal processing unit 124 increases the power of the subcarrier at the peak point of interference from the DL signal by the amount by which the power of the subcarrier arranged at the null point is reduced. The peak point of interference is, for example, an intermediate point between adjacent null points of interference signals from adjacent blocks on the frequency axis. The base station 20 assigns power sufficient to allow channel estimation of the radio propagation path to the subcarrier in which the RS is inserted at the interference null point, and assigns the remaining power to the subcarrier having strong interference.

(Effect of Example 7)
According to the communication system 1 of the seventh embodiment, even when the UL receives interference from the DL block, it is possible to improve the estimation accuracy of the channel of the UL radio channel and further improve the decoding accuracy of the UL signal. Can be improved.

FIG. 23 is a diagram for explaining an example of frequency band allocation to each block in the communication system according to the eighth embodiment. The block setting unit 220 of the base station 20a according to the eighth embodiment determines a frequency band to be allocated to the block according to the OFDM symbol length of the block.

For example, as shown in FIG. 23, consider a case where four blocks of UL # 1, # 2, # 3 and DL block are allocated within a 20 MHz frequency band. Here, it is assumed that the OFDM symbol length of the UL # 3 block is longer than the OFDM symbol length of the UL # 2 block. Further, it is assumed that the OFDM symbol length of the UL # 2 block is longer than the OFDM symbol length of the UL # 1 block. *

In this case, the block setting unit 220 of the base station 20a allocates a block having a short OFDM symbol length from the lowest frequency band in the communication band. Thus, the OFDM symbol length is assigned sequentially from the lowest frequency band in ascending order. Specifically, for example, as illustrated in FIG. 23, the block setting unit 220 assigns frequency bands in the order of a block of UL # 1, a block of UL # 2, and a block of UL # 3 from a low frequency band. The block setting unit 220 assigns the highest frequency band to the DL block. Accordingly, for example, as illustrated in FIG. 23, a UL block having a short symbol length is arranged away from a DL block serving as a large interference source in the communication band.

(Effect of Example 8)
According to the communication system 1 of the eighth embodiment, the UL block in which the difference in OFDM symbol length is short and the interference in the subcarrier unit is difficult to avoid is arranged away from the DL block that causes a large interference, so The influence of interference received from the block can be reduced.

In the fifth to eighth embodiments described above, the terminal device 10a inserts an RS into the UL based on the UL RS information notified from the base station 20a, but the disclosed technology is not limited to this. For example, the terminal device of the communication system 1 may calculate the subcarrier position where the RS is inserted in the UL based on the filtering information notified from the base station, and may insert the RS into the calculated subcarrier position. An example in this case will be described below as Example 9.

FIG. 24 is a diagram illustrating an example of a base station according to the ninth embodiment. FIG. 25 is a diagram illustrating an example of the terminal device according to the ninth embodiment. Except as described below, blocks denoted by the same reference numerals in FIG. 24 as those in FIG. 17 have the same or similar functions as the blocks in FIG. In addition, except for the points described below, blocks denoted by the same reference numerals in FIG. 25 as those in FIG. 18 have the same or similar functions as the blocks in FIG.

The communication system 1 according to the ninth embodiment includes a base station 20b and a terminal device 10b. The base station 20b of the present embodiment does not notify the terminal device 10b of UL RS information. Therefore, for example, the UL RS insertion calculation unit 229 of the base station 20b illustrated in FIG. 24 does not notify the block setting unit 220 of UL RS information. Further, the radio control signal processing unit 223 does not include UL RS information in the broadcast information to the terminal device 10b.

For example, as illustrated in FIG. 25, the terminal device 10 b includes a UL RS insertion calculation unit 127 b instead of the UL RS information reception unit 127. The UL RS insertion calculating unit 127b uses the filtering information notified from the block receiving unit 120 to calculate the subcarrier position where the RS is inserted in the UL, and notifies the UL signal processing unit 124 of the result as RS information. . The UL RS insertion calculation unit 127b calculates the subcarrier position into which the RS is inserted in the UL using the same calculation method as the UL RS insertion calculation unit 229 of the base station 20b.

(Effect of Example 9)
According to the communication system 1 of the ninth embodiment, the base station 20b does not need to notify the terminal device 10b of the RS information because the subcarrier position at which the RS is inserted in the UL is calculated on the terminal device 10b side. Therefore, the data amount of the broadcast information transmitted from the base station 20b to the terminal device 10b can be reduced.

In the communication system 1, out-of-band interference may occur in adjacent UL blocks due to a power difference between UL blocks. In such a case, in the communication system 1, an RS may be inserted into a subcarrier at a null point of out-of-band interference in a block that receives UL interference. An embodiment in this case will be described below as a tenth embodiment. In the following, the same components as those in the first to ninth embodiments are denoted by the same reference numerals and description thereof is omitted.

FIG. 26 is a diagram illustrating an example of received power in the communication system and the base station according to the tenth embodiment. FIG. 27 is a diagram for explaining an example of out-of-band interference in the communication system according to the tenth embodiment. FIG. 28 is a schematic diagram illustrating an example of an RS insertion position in the communication system according to the tenth embodiment.

First, a situation where out-of-band interference occurs in adjacent UL blocks due to a power difference between UL blocks will be described with reference to FIGS. 26 and 27. FIG. Here, the communication system 1 includes a base station 20c and a terminal device 10c, and the terminal device 10c will be described as an example of a data communication terminal and a meter reading device. In the communication system 1 illustrated in FIGS. 26 and 27, the frequency band block used by the data communication terminal for the UL is, for example, an f2 block, and the frequency band block used by the meter reading unit for the UL is, for example, an f1 block. is there.

In the communication system 1 of the present embodiment, power control during transmission of the UL signal is performed on the terminal device 10c side in order to maintain the reception quality of the UL signal in the base station 20c.

For example, when the terminal device 10c is a data communication terminal, a UL signal is transmitted with high power in order to send as much data as possible at a time. On the other hand, when the terminal device 10c is a meter-reading device, a UL signal is transmitted with low power in order to transmit data while suppressing power consumption as much as possible. Therefore, for example, as shown in FIG. 26, the received power from the data communication terminal in the base station 20c is higher than the received power from the meter-reading device in the base station 20c.

Here, when different blocks are allocated to each terminal apparatus 10c by F-OFDM and the OFDM symbol length of each block is different, out-of-band interference occurs in the base station 20c. That is, for example, as shown in FIG. 27B, when the OFDM symbol length is different between the f2 block and the f1 block, for example, as shown in FIG. 27A, the bandwidth from the f2 block to the f1 block External interference occurs. In particular, the greater the difference in received power at the base station 20c between the block f2 and the block f1, the more this out-of-band interference cannot be ignored.

Therefore, for example, as illustrated in FIG. 28, the terminal device 10 c of the communication system 1 inserts an RS into a subcarrier at a position where out-of-band interference from the f2 block becomes a null point among the subcarriers of the f1 block. . By doing in this way, the communication system 1 can suppress a decrease in communication quality of the UL block even when out-of-band interference occurs in the UL block due to a power difference between the UL blocks. it can.

FIG. 29 is a diagram illustrating an example of a base station according to the tenth embodiment. FIG. 30 is a diagram illustrating an example of the terminal device according to the tenth embodiment. Except for the points described below, in FIG. 29, blocks denoted by the same reference numerals as those in FIG. 5 or FIG. 17 have the same or similar functions as the blocks in FIG. Also, except for the points described below, in FIG. 30, blocks denoted by the same reference numerals as those in FIG. 6 or FIG. 18 have the same or similar functions as the blocks in FIG.

The base station 20c according to the tenth embodiment includes a UL RS insertion calculation unit 229 as illustrated in FIG. 29, for example. When the base station 20c calculates which subcarrier position of the UL block the RS is to be inserted into by the UL RS insertion calculation unit 229, the base station 20c notifies the terminal device 10c of RS information indicating the calculation result. Further, the terminal device 10c includes a UL RS information receiving unit 127 as shown in FIG. 30, for example. When the terminal device 10c receives the RS information from the base station 20c by the UL RS information receiving unit 127, the terminal device 10c inserts an RS into the UL signal based on the received RS information, and transmits the RS signal to the base station 20c.

(Processing procedure)
Next, the processing procedure of the base station 20c will be described with reference to FIG. FIG. 31 is a flowchart illustrating an example of a processing procedure of the base station according to the tenth embodiment. The base station 20c determines a UL F-OFDM block and its filter (S41), and calculates a UL RS insertion interval (S42). That is, when the base station 20c determines the UL F-OFDM block and its filter, the UL RS insertion calculation unit 229 determines the subcarrier position where the RS is inserted in the UL block based on the determined block and its filter. The RS information to be shown is determined.

Then, the base station 20c notifies UL filtering information and UL RS information (S43). That is, the block setting unit 220 of the base station 20c notifies the UL F-OFDM unit 221 of the UL F-OFDM block determined in step S41 and the filtering information indicating the filter. Also, the UL RS insertion calculating unit 229 of the base station 20c notifies the UL signal processing unit 222 of the RS information determined in step S42. Further, the base station 20c transmits broadcast information including UL filtering information and UL RS information to the terminal device 10c.

Next, the base station 20c applies UL filtering information and UL RS information (S44), and receives UL data transmitted from the terminal device 10c (S45). That is, the UL F-OFDM unit 221 of the base station 20c applies the filter based on the UL filtering information notified in step S43. Then, when the RF receiving unit 210 receives the UL signal in which the RS is inserted by the terminal device 10c, the UL F-OFDM unit 221 performs a filtering process on the UL signal. Thereafter, the UL signal processing unit 222 estimates the UL radio propagation channel based on the UL RS information notified in step S43, and demodulates the UL signal based on the estimated channel information.

Next, the processing procedure of the terminal device 10c will be described with reference to FIG. FIG. 32 is a flowchart illustrating an example of a processing procedure of the terminal device according to the tenth embodiment. The terminal device 10c receives the broadcast information transmitted from the base station 20c (S51). That is, the DL signal processing unit 122 of the terminal device 10c receives the broadcast information transmitted from the base station 20c.

Next, the terminal device 10c extracts UL filtering information and UL RS information from the broadcast information received in step S51 (S52). That is, the radio control signal processing unit 123 of the terminal device 10c extracts UL filtering information and UL RS information from the broadcast information received by the DL signal processing unit 122.

Next, the terminal device 10c applies UL filtering information and UL RS information (S53), and transmits UL data (S54).

That is, the block receiving unit 120 of the terminal device 10c notifies the UL F-OFDM unit 125 of the UL filtering information extracted in step S52. Also, the UL RS information receiving unit 127 of the terminal device 10c notifies the UL signal processing unit 124 of the UL RS information extracted in step S52. Thereafter, the UL signal processing unit 124 inserts the RS into the UL subcarrier at the position indicated by the notified RS information, and outputs it to the UL F-OFDM unit 125. The UL F-OFDM unit 125 performs filtering processing on the UL signal output from the UL signal processing unit 124 based on the notified filtering information. Thereafter, the RF transmission unit 111 transmits the filtered UL signal to the base station 20c.

(Effect of Example 10)
According to the communication system 1 of the tenth embodiment, even when out-of-band interference occurs in the UL block due to the power difference between the UL blocks, it is possible to suppress a decrease in the communication quality of the UL block. .

(Other)
The disclosed technology is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist. For example, among the processes described in the above-described embodiments, all or part of the processes described as being performed automatically can be performed manually, or the processes described as being performed manually All or a part of the above can be automatically performed by a known method. In addition, the processing procedure, control procedure, specific name, and information including various data and parameters shown in the above-described document and drawings can be arbitrarily changed unless otherwise specified.

Also, each component of each illustrated device is functionally conceptual and may not necessarily be physically configured as illustrated. In other words, the specific form of distribution / integration of each device is not limited to that shown in the figure, and all or a part thereof may be functionally or physically distributed or arbitrarily distributed in arbitrary units according to various loads or usage conditions. Can be integrated and configured. Further, all or any part of each processing function performed in each device may be realized by a CPU and a program analyzed and executed by the CPU, or may be realized as hardware by wired logic.

Note that the communication method described in each embodiment can be realized by executing a program prepared in advance by a processor included in the base station and the terminal device. This program can be distributed via a network such as the Internet. The program can also be executed by being recorded on a computer-readable recording medium and being read from the recording medium by a processor included in the base station and the terminal device. Examples of the computer-readable recording medium include a hard disk, a flexible disk (FD), a CD-ROM (Compact Disc-Read Only Memory), an MO (Magneto-Optical disc), and a DVD (Digital Versatile Disc).

10, 10a, 10b, 10c Terminal device 11, 21 RF module 12, 22 DSP
13 MPU
14, 24 Memory 20, 20a, 20b, 20c Base station 23 NWP
110, 210 RF receiver 111, 211 RF transmitter 120 Block receiver 121, 225 F-OFDM unit for DL 122, 224 DL signal processor 123, 223 Radio control signal processor 124, 222 UL signal processor 125, 221 UL F-OFDM unit 126 DL RS information receiving unit 127 UL RS information receiving unit 127b, 229 UL RS insertion calculating unit 128 TA receiving unit 129 Delay unit 130, 230 IP processing unit 131 Application processing unit 220 Block setting unit 226 Radio scheduler unit 227 DL RS insertion calculation unit 228 synchronization unit

Claims (9)

1. A base station that performs wireless communication with a terminal device,
   A setting unit that sets the OFDM symbol length of each block so that the OFDM symbol length of each of the blocks of different frequency bands generated in one carrier is an integral multiple of the shortest OFDM symbol length among the blocks. When,
   A calculation unit that calculates a position of a subcarrier of the second block at which out-of-band interference from the first block to the second block becomes a null point;
   In a downlink signal, a signal processing unit that inserts a reference signal used for channel estimation of a radio propagation path into a subcarrier at a position calculated by the calculation unit, and transmits the reference signal to the terminal device;
   A base station comprising:
2. A terminal device that performs wireless communication with a base station,
   Out of a plurality of blocks in different frequency bands transmitted from the base station, out-of-band interference from the first block to the second block is inserted at a subcarrier position of the second block that becomes a null point. A receiver for receiving a reference signal used for estimating a radio propagation path;
   A signal processing unit that estimates a channel of a downlink radio propagation path transmitted from the base station using the reference signal, and performs reception processing of the downlink signal using the estimated channel;
   A terminal device comprising:
3. A communication system having a terminal device and a base station,
   The base station
   A setting unit that sets the OFDM symbol length of each block so that the OFDM symbol length of each of the blocks of different frequency bands generated in one carrier is an integral multiple of the shortest OFDM symbol length among the blocks. When,
   A calculation unit that calculates a position of a subcarrier of the second block at which out-of-band interference from the first block to the second block becomes a null point;
   In a downlink signal, a first signal processing unit that inserts a reference signal used for channel estimation of a radio propagation path into a subcarrier at a position calculated by the calculation unit, and transmits the reference signal to the terminal device;
   With
   The terminal device
   A receiving unit for receiving a reference signal included in a downlink signal transmitted from the base station;
   A second signal processing unit that performs reception processing of the downlink signal using the reference signal;
   A communication system comprising:
4. In a communication system having a terminal device and a base station,
   The base station is
   Setting the OFDM symbol length of each block of a plurality of different frequency bands generated on one carrier to be an integral multiple of the shortest block of the OFDM symbol length among the blocks,
   Calculating the position of the subcarrier of the second block where the out-of-band interference from the first block to the second block is a null point;
   In the downlink signal, insert a reference signal used for channel estimation of the radio propagation path into the subcarrier at the calculated position, and execute processing to transmit to the terminal device,
   The terminal device is
   Receiving the reference signal included in the downlink signal transmitted from the base station;
   A communication method comprising: performing reception processing of the downlink signal using the reference signal.
5. A base station that performs wireless communication with a terminal device,
   A setting unit that sets the OFDM symbol length of each block so that the OFDM symbol length of each of the blocks of different frequency bands generated in one carrier is an integral multiple of the shortest OFDM symbol length among the blocks. When,
   A calculating unit that calculates a position of a subcarrier of the second block from which the out-of-band interference to the second block allocated to the uplink becomes a null point from the first block allocated to the downlink;
   A signal processing unit that notifies the terminal device of the position of the subcarrier calculated by the calculation unit as a reference signal insertion position used for channel estimation of the radio propagation path of the second block;
   A base station comprising:
6. The base station further includes:
   The base station according to claim 5, further comprising a synchronization unit that synchronizes rising edges of OFDM symbols of the respective blocks.
7. A terminal device that performs wireless communication with a base station,
   RS information for receiving a position of a subcarrier serving as an insertion position of a reference signal used for channel estimation of a radio channel of a block allocated to an uplink among a plurality of blocks of different frequency bands transmitted from the base station A receiver,
   In an uplink signal, a signal processing unit that inserts the reference signal at a position of a subcarrier of a block allocated to the received uplink and transmits the signal to the base station;
   A terminal device comprising:
8. A communication system having a terminal device and a base station,
   The base station
   A setting unit that sets the OFDM symbol length of each block so that the OFDM symbol length of each of the blocks of different frequency bands generated in one carrier is an integral multiple of the shortest OFDM symbol length among the blocks. When,
   A calculating unit that calculates a position of a subcarrier of the second block from which the out-of-band interference to the second block allocated to the uplink becomes a null point from the first block allocated to the downlink;
   A first signal processing unit that notifies the terminal device of the position of the subcarrier calculated by the calculation unit as an insertion position of a reference signal used for channel estimation of a radio propagation path;
   With
   The terminal device
   From the base station, an RS information receiving unit that receives a position of a subcarrier to be the insertion position of the reference signal
   A second signal processing unit that inserts the reference signal at a position of the received subcarrier in an uplink signal and transmits the signal to the base station;
   A communication system comprising:
9. In a communication system having a terminal device and a base station,
   The base station is
   Setting the OFDM symbol length of each block of a plurality of different frequency bands generated on one carrier to be an integral multiple of the shortest block of the OFDM symbol length among the blocks,
   From the first block assigned to the downlink, calculate the subcarrier position of the second block where the out-of-band interference to the second block assigned to the uplink is a null point;
   A process of notifying the terminal device of the calculated position of the subcarrier as a reference signal insertion position used for channel estimation of a radio propagation path;
   The terminal device is
   From the base station, the position of the subcarrier that is the insertion position of the reference signal is received,
   In the uplink signal, the communication method which performs the process which inserts the said reference signal in the position of the received said subcarrier, and transmits to the said base station is performed.

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