JP7381261B2 - Wireless base station equipment and wireless network system - Google Patents

Description

The present invention relates to a wireless base station device and a wireless network system using the same.

BACKGROUND ART In radio base station devices used in mobile communication systems, devices in which a diversity receiving section is formed by a transmitting/receiving antenna and a receiving antenna are generally used (Patent Document 1). In this type of radio base station device, the circuit on the transmitting and receiving antenna side uses a high frequency antenna switch to isolate the receiving circuit and the transmitting circuit. On the other hand, since there is no need to switch between the reception-only antenna and the transmission circuit, no switch or the like is provided on the reception-only antenna side. When a radio base station device having such a configuration is used in a transmission mode, a transmission wave from a transmitting/receiving antenna also goes around to its own receiving antenna and is received, and a signal current flows to the receiving circuit side. In the case of a general wireless base station used in a mobile communication system, the transmission output is approximately 200 mW at most in the case of a TD-LTE wireless base station, for example, and the transmitted wave flows into the receiving circuit side of the receive-only antenna. But it won't have a big impact.

Japanese Patent Application Publication No. 11-308199 Ministry of Land, Infrastructure, Transport and Tourism Public Broadband Mobile Communication System Standard Specifications (Kokuden Tsusho No. 56 (established February 8, 2016))

However, in recent years, wireless base stations with extremely high transmission power are sometimes required, mainly for the following uses. In other words, public communication systems used by the national and local governments, police, fire departments, and emergency services at disaster sites have mainly been voice-based, but in order to share accurate information from disaster areas, etc. There is a need for a means of video transmission. Therefore, studies are underway to use part of the VHF band, which has become vacant due to the digitalization of terrestrial television broadcasting, for a public broadband mobile communication system that meets the above objectives. The public broadband mobile communication system is being standardized by the Ministry of Land, Infrastructure, Transport and Tourism (Non-Patent Document 1), and a frequency band is allocated to the 200 MHz band (VHF band from 172.5 MHz to 202.5 MHz), and the following It has many advantages.

- Since it uses the VHF band reserved exclusively for public institutions (national and local governments, police and fire departments, etc.), prompt disaster prevention and countermeasures are possible.
・The VHF band, which has a long wavelength, has a large wraparound and is suitable for safety and security applications that require the minimization of dead zones in Japan, which has a complex topography. Specifically, it will enable long-distance transmission with a maximum line-of-sight of 27.8 km (theoretical value) and communication in locations where visibility is difficult due to mountains or buildings. Furthermore, it is not easily affected by the weather, and communication is easy even in heavy rain or heavy snow, for example.
- It is possible to communicate between a portable base station and a plurality of mobile terminal devices, and it is possible to easily construct a private wireless network that does not depend on public networks, and it is also possible to connect to existing IP networks.

However, in the case of a wireless base station intended for long-distance transmission as described above, the power of the transmitted wave is set to a very large value of 5 W or more, for example in the case of the above-mentioned public broadband mobile communication system standard. When such a high-power transmitted wave goes around to the receive-only antenna and is received, an excessive current flows into the receiving circuit, causing excessive input to the high-frequency low-noise amplifier that amplifies the received wave signal. There is a problem with being more susceptible to damage. Such problems are particularly likely to occur in installation situations where a sufficient distance between the transmitting and receiving antennas and the receiving antennas cannot be secured.

The problem to be solved by the present invention is that in a radio base station device having a diversity receiving section with a transmitting/receiving antenna and a receiving antenna, and a wireless network system using the same, even when the transmitting power is set to a large value, even when the receiving antenna is The purpose of the present invention is to protect a high frequency low noise amplifier included in a receiver circuit from damage caused by reception of transmitted waves.

In order to solve the above problems, a radio base station device of the present invention includes a modulation/demodulation circuit that modulates a transmitted wave and demodulates a received wave, a transmitting/receiving antenna, and a transmitting/receiving antenna that amplifies the transmitted wave signal and outputs it to the transmitting/receiving antenna. A transmission side power amplifier, a first high frequency low noise amplifier that amplifies the received wave signal received by the transmission and reception antenna and outputs it to a modulation/demodulation circuit, and a connection path between the transmission and reception antenna, the transmission side power amplifier, and the first high frequency low noise amplifier. The transmitting side power amplifier is connected to the receiving connection state, which is installed on the top and is insulated and cut off from the transmitting side power amplifier, and is electrically connected to the first high frequency low noise amplifier, and the transmitting/receiving antenna is electrically connected to the transmitting side power amplifier. A transmitting/receiving side switch section that switches between a transmitting connection state in which the first high frequency low noise amplifier is electrically connected and isolated from the first high frequency low noise amplifier, a receiving only antenna that forms a diversity receiving section together with the transmitting and receiving antenna, and a receiving only antenna. a second high-frequency low-noise amplifier that amplifies the received received wave signal and inputs it to the modulation/demodulation circuit; and a second high-frequency low-noise amplifier that is provided between the second high-frequency low-noise amplifier and the receive-only antenna; When the reception-only side switch switches the connection state between the conduction state and the cutoff state, and the transmission and reception side switch section is in the reception connection state, the reception-only side switch becomes conduction state, and the transmission and reception side switch section is in the transmission connection state. The operation of the transmitter/receiver switch unit and the receive-only switch is controlled so that the receive-only switch is in a cutoff state when The present invention is characterized by comprising a switch control unit that delays the timing at which the side switch switches from conduction to cutoff by a certain period of time .

Further, the wireless network system of the present invention is a wireless network system that performs mobile communication between a wireless base station device and a mobile terminal device wirelessly connected to the wireless base station device, in which the wireless base station device The present invention is characterized in that it is configured as the radio base station of the present invention.

In the wireless base station device of the present invention, the second high frequency low noise amplifier can have an input upper limit of 25 dBm or less, and the transmitter side power amplifier can have a transmission output of 4 W or more. Further, the radio base station device can be configured to be used in a public broadband mobile communication system to which a frequency band ranging from 172.5 MHz to 202.5 MHz is allocated.

Further, in the wireless base station device of the present invention, the transmitting/receiving side switch unit can be configured as an SPDT switch that selectively connects the transmitting/receiving antenna to the transmitting side power amplifier and the first high frequency low noise amplifier, and the receiving side switch is , can be configured as an SPST switch provided on the input path from the receive-only antenna to the second high-frequency low-noise amplifier.

Further, in the wireless base station device of the present invention, the switch control section distributes and inputs the switch control signal to the transmitting/receiving side switch section to the receiving-only switch, thereby synchronously operating the transmitting/receiving side switch section and the receiving-only side switch. It can be configured as something to control.

In the wireless base station device and the wireless communication system of the present invention, a reception-only side switch is provided between the reception-only antenna and the second high-frequency low-noise amplifier, and when the transmission and reception side switch unit is in the transmission connection state, the reception-only side The switch is controlled so that the switch is in the cutoff state. As a result, even if the transmission wave is transmitted with high power, the second high frequency low noise amplifier can be effectively protected from damage caused by reception that wraps around the reception-only antenna.

FIG. 1 is a block diagram showing an overview of the configuration of a wireless communication system according to the present invention. FIG. 1 is a block diagram showing an example of the electrical configuration of a portable base station device that is an embodiment of the present invention. FIG. 1 is a block diagram showing an example of the electrical configuration of a mobile terminal device of the present invention. FIG. 4 is a block diagram showing the electrical configuration of a wireless communication unit (at the time of reception) of the wireless base station unit of the portable base station device in FIG. 3; FIG. 5 is a block diagram showing an example of an electrical configuration of a modulation section of the wireless communication section in FIG. 4. FIG. FIG. 5 is a block diagram showing an example of an electrical configuration of a demodulation section of the wireless communication section in FIG. 4. FIG. A conceptual diagram of an IP packet. FIG. 2 is a diagram conceptually showing a 3GPP control plane protocol stack. FIG. 2 is a diagram conceptually showing a 3GPP user plane protocol stack. FIG. 3 is a diagram conceptually showing 3GPP downlink channel mapping. FIG. 4 is a diagram conceptually showing uplink channel mapping. FIG. 3 is a conceptual diagram showing the relationship between frequency band channels and resource blocks. FIG. 4 is a diagram illustrating the setting of the arrangement interval between the transmitting/receiving antenna and the receiving-only antenna of the portable base station device of FIG. 3; FIG. 5 is a block diagram showing the state of the wireless communication unit in FIG. 4 during transmission. FIG. 5 is a block diagram illustrating a modification example in which switch control signals are individually transmitted to a transmitter/receiver switch unit and a receive-only switch in the wireless communication unit of FIG. 4; FIG. 16 is a timing chart showing an example of switching the transmitting/receiving side switch unit to the transmitting state by delaying the switching to the blocking state of the receiving-only switch for a predetermined period of time in the configuration of FIG. 15; FIG. 3 is a circuit diagram illustrating an example in which the function of a transmitter/receiver switch section equivalent to an SPDT switch is realized by a combination of two sets of SPST switches. FIG. 18 is a circuit diagram illustrating an example of a configuration in which the transmitting/receiving side switch section has the configuration shown in FIG. 17 and includes a receiving-only side switch, and transmitting switching and receiving switching are controlled by separate switch control signals.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described based on the accompanying drawings.
FIG. 1 is a schematic diagram conceptually showing an example of a wireless communication system of the present invention. The wireless communication system 50 transmits a plurality of signals via the portable base station device 1 in accordance with a communication protocol stack of a method defined by 3GPP (in this embodiment, LTE is used, but other methods such as WiMAX may also be used). It is configured to perform wireless communication between UEs (mobile terminal devices) 5.

The portable base station device 1 of the wireless communication system 50 is installed at the site of a disaster, etc., and constructs a public broadband mobile communication system capable of video transmission, etc. for sharing accurate information of the disaster area, etc. The public broadband mobile communication system is allocated a 200 MHz VHF band, that is, a band ranging from 172.5 MHz to 202.5 MHz, as a frequency band to be used. As described later, the portable base station device 1 can procure power supply voltage from a battery, a private power generation device, etc., and can easily construct a private wireless network that does not depend on the public network. The UEs 5 are carried by operators of the portable base station device 1, and are each connected to the portable base station device 1 by a radio bearer 57.

The portable base station device 1 has a wireless base station unit (eNodeB (evolved NodeB)) 4 and an EPC (Evolved Packet Core) function that is connected by wire to the wireless base station unit 4 and functions as an upper network control unit for the wireless base station unit 4. It has part 3. In the drawings attached to this specification, arrow lines indicating radio bearers are shown as broken lines, and wired bearers or electrical connection lines are shown as solid lines or dash-dotted arrow lines. The portable base station device 1 and thus the radio base station section 4 constitute one embodiment of the radio base station device of the present invention.

The EPC function unit 3 includes an MME (Mobility Management Entity) 2 that is a gateway on the control plane side, an S-GW (Serving Gateway) 6 that is a gateway on the user plane side, and an upstream network element (here, a router 8). It has a P-GW (PDN (Packet Data Network) Gateway) 7 that is located at a node of the network and manages IP addresses for upstream network elements. The router 8 connects to an external network 60 by wireless (for example, satellite communication) or wired connection, and has the function of acquiring content data such as moving images (videos) to be distributed through public broadband communication.

On the control plane side, the radio base station unit (eNodeB) 4 is connected to the MME 2 via the S1-MME interface. Furthermore, on the user plane side, the wireless base station section 4 is connected to the S-GW 6 via the S1-U interface. The S-GW 6 is connected to the P-GW 7 via the S5 interface.

FIG. 2 is a block diagram showing an example of the electrical configuration of the portable base station device 1. As shown in FIG. The EPC function unit 3 is mainly composed of microcomputer hardware, including a CPU 301, a RAM 302 serving as a program execution area, and a mask ROM 303 (stores firmware for microcomputer hardware peripheral control that does not require permanent rewriting); (the same applies hereinafter) and a bus 306 that interconnects them. Further, a flash memory 305 is connected to the bus 306, and communication firmware 305a including an LTE protocol stack for EPC is stored therein, and each of the MME2, S-GW6, and P-GW7 in FIG. 2 uses the LTE protocol stack as a platform. Programs for an MME entity 305b, an S-GW entity 305c, and a P-GW entity 305d, which virtually implement functions, are installed.

Further, an upstream communication interface 304A and a downstream communication interface 304B are connected to the bus 306. An input/output port for IP packets for P-GW is secured in the upstream communication interface 304A, and an input/output port for IP packets for S-GW is secured in the downstream communication interface 304B. Note that in the above configuration, the MME2, S-GW6, and P-GW7 in FIG. 2 are configured as virtual function blocks realized by software on computer hardware, but each is configured by independent hardware logic. You may.

The wireless base station unit 4 is mainly composed of microcomputer hardware, and includes a CPU 401, a RAM 402 serving as a program execution area, a mask ROM 403, a bus 406 that interconnects them, and the like. A flash memory 405 is connected to the bus 406, and includes communication firmware 405a including an LTE protocol stack for wireless base stations, switch switching control firmware 405b (realizing the function of a switch switching control unit), and received wave phase control firmware 405c. is stored. Further, a wireless communication unit 412 and a communication interface 404 are connected to the bus 406 for wirelessly connecting to the UE 5 by constructing a radio bearer. The communication interface 404 is connected to the communication interface 304 of the EPC function section 3 via the wired communication bus 31. The wireless communication section 412 is provided with a transmitting/receiving antenna 105A and a receiving antenna 105B, forming a diversity receiving section.

Next, the portable base station device 1 includes a removable secondary battery module 21 (for example, a lithium ion secondary battery module, a nickel metal hydride secondary battery module, etc.), and each of the wireless base station section 4 and the EPC function section 3. It has a structure in which a circuit block and a power supply circuit section 22 that converts the input voltage from the secondary battery module 21 into a driving voltage for each circuit block and outputs it are assembled into a portable casing 23. As a result, the portable base station device 1 can autonomously procure the driving power supply voltage from the secondary battery module 21, and can be installed in locations where external power supply voltages such as commercial AC cannot be used (for example, in disaster-stricken areas during power outages). It can also be used without any problem. The portable housing 23 is box-shaped and made of metal or reinforced resin.

If the output voltage of the secondary battery module 21 drops due to discharge, remove the secondary battery module 21 from the portable housing 23 and attach it to a dedicated charger connected to a commercial AC power source or private power generator (not shown), for example. It is possible to charge the battery. The power supply circuit section 22 is also capable of receiving external power supply voltage from the above-mentioned commercial alternating current or private power generation device, or the power supply lid of a battery-equipped vehicle such as an electric vehicle or a hybrid vehicle, and is adapted to the above-mentioned drive power supply voltage. Conversion output is possible. Furthermore, it is also possible to configure the secondary battery module 21 to be charged using the external power supply voltage. For example, if the power supply circuit unit 22 is receiving power from a commercial alternating current or the like and the power reception is interrupted due to a power outage, the operation of the portable base station device 1 can be continued by switching to receiving power from the secondary battery module 21. It can also be configured as follows.

FIG. 4 is a block diagram showing an example of the electrical configuration of the wireless communication unit 412. The wireless communication unit 412 includes an interface unit 464 for inputting and outputting digital signals with the bus 406 of the microcomputer hardware shown in FIG. Receiving a transmission/reception switching signal from the transmitter block 410R, the transmitter/receiver antenna 105A, the receive-only antenna 105B, and the microcomputer hardware side, the receiver block 410T and the transmitter block 410R are selectively switched to the transmitter/receiver antenna 105A. It includes a transmitting/receiving antenna switch 451 for switching connection, and a receiving only switch 471 for switching the electrical connection state between the receiving antenna 105B and the receiving block 410T between conduction and disconnection.

The receiving block 410T and the transmitting block 410R individually support multiple modulation and demodulation methods for performing adaptive modulation, such as QPSK (Quadrature Phase shift Keying), 16QAM (16 Quadrature Amplitude Modulation), or 64QAM (16 Quadrature Amplitude Modulation). However, since the configuration of these modulation/demodulation circuits is well known, a configuration as a QPSK modulation/demodulation circuit will be described here as a representative example.

The transmitting side block 410R includes a modulation circuit 700 that generates an analog transmitting wave signal by modulating a carrier wave using the serial transmitting data signal inputted from the interface section 464 as a baseband signal, and the analog transmitting wave signal is generated by transmitting side power. The signal is amplified by an amplifier (hereinafter also simply referred to as a power amplifier) 453 and supplied to the transmitting/receiving antenna 105A. In this embodiment, the rated upper limit value of the power transmitted by the power amplifier 453 from the transmitting/receiving antenna 105A is set to 5W.

The receiving block 410T also includes band pass filters 462 and 472 for extracting desired waves from antenna received signals, high frequency low noise amplifiers 463 and 473 for amplifying the received wave signals after passing through the band pass filters 462 and 472, and A demodulation circuit 600 is provided that demodulates a baseband signal from the received wave signals output from the high frequency low noise amplifiers 463 and 473 and converts it into serial received data.

Specifically, a first high-frequency low-noise amplifier 463 is provided on the transmitting/receiving antenna 105A side, which amplifies the received wave signal received by the transmitting/receiving antenna 105A and passes through the bandpass filter 462, and outputs the amplified signal to the demodulation circuit 600. ing. On the other hand, on the reception-only antenna 105B side, a second high-frequency low-noise amplifier 473 is provided that amplifies the received wave signal received by the reception-only antenna 105B and passed through the band-pass filter 472, and inputs the amplified signal to the demodulation circuit 600. . The received wave signal from the transmitting/receiving antenna 105A and the received wave signal from the receive-only antenna 105B are adjusted by a phase shifter 481 and a phase shifter 482 so that the phase shifts match each other, and then adjusted by a mixer 483. The mixed signals are input to the demodulation circuit 600. Note that the phase control signals to the phase shifters 481 and 482 are output from the interface section 464 in FIG. 4 when the CPU 401 in FIG. 2 executes the received wave phase control firmware 405c.

In the above configuration, modulation circuit 700 and demodulation circuit 600 constitute a modulation/demodulation circuit. FIG. 5 shows a configuration example of the modulation circuit 700, in which the waveform of a serial transmission data signal is separated into two channels (Ich/Qch) parallel bit signals by a serial/parallel converter 720, and each is subjected to D/A conversion. 717 and 719 and low-pass filters 716 and 718, the signal is converted into an analog baseband signal. The analog baseband signal of each channel is passed through multipliers 715 and 713 to a sine wave carrier (one of which is advanced by 90° by a phase shifter 714) from an oscillation circuit 712 consisting of a voltage controlled oscillation circuit VCO and a phase-locked loop circuit PLL. ) into orthogonal frequency modulated waves, which are further mixed by a duplexer 721 and output as an analog transmission wave signal.

FIG. 6 shows a configuration example of the demodulation circuit 600, in which the analog reception wave signal from the reception front end section 630 is multiplied by the sine wave demodulation signal from the transmission circuit 612 (one of which is phase-shifted). (advanced by 90 degrees by a receiver 614) to produce Ich and Qch baseband signals. These baseband signals are further converted into parallel bit signals by low-pass filters 616, 618 and A/D converters 617, 619, and further converted into serial reception data signals by a parallel/serial converter 620, and then converted to a serial reception data signal by the interface unit in FIG. 464.

Returning to FIG. 4, the transmitting/receiving side switch section 451 is provided in a connection path between the transmitting/receiving antenna 105A, the transmitting side power amplifier 453, and the first high frequency low noise amplifier 463. In this embodiment, the transmitting/receiving antenna 105A is configured as an SPDT switch that selectively connects the transmitting side power amplifier 453 and the first high frequency low noise amplifier 463, thereby reducing the number of switches and simplifying the control form thereof. ing. The transmitter/receiver side switch unit 451 transmits a switch control signal (first level (for example, H level) output from the interface unit 464 in FIG. 4 to the transmitter side by the CPU 401 in FIG. The switching is controlled by the second level (for example, L level), which is a binary level signal corresponding to switching to the receiving side.

Specifically, by switching to the transmitting side, the electrical connection state of the transmitting/receiving antenna 105A is changed to a receiving connection state in which the transmitting/receiving antenna 105A is insulated and cut off from the transmitting side power amplifier 453, while being electrically connected to the first high frequency low noise amplifier 463. state. On the other hand, by switching to the receiving side, the electrical connection state of the transmitting/receiving antenna 105A becomes a transmitting connection state in which it is electrically connected to the transmitting side power amplifier 453 but insulated and disconnected from the first high frequency low noise amplifier 463. .

Further, the reception-only side switch 471 is provided between the second high-frequency low-noise amplifier 473 and the reception-only antenna 105B. In this embodiment, the reception-only switch 471 is configured as an SPST switch, and switches the connection state between the reception-only antenna 105B and the second high-frequency low-noise amplifier 473 between a conduction state and a cutoff state. In this embodiment, both the first high-frequency low-noise amplifier 463 and the second high-frequency low-noise amplifier 473 are commercially available products (for example, TQP3M9008 manufactured by Qorvo, USA), and the upper limit of the rated input is +23 dBm (conditions: Continuous wave, input impedance: 50Ω, temperature 25°C).

By receiving the switch control signal accompanying the execution of the switch switching control firmware 405b, the reception-only side switch 471 becomes conductive when the transmission/reception side switch unit 451 enters the reception connection state shown in FIG. When the transmitting connection state is established, the operation is controlled so that the transmitting state is set to the cutoff state. In this embodiment, a switch control signal (of one system) to the transmitter/receiver switch unit 451 is distributed to the receive-only switch 471, so that the transmitter/receiver switch unit 451 and the receive-only switch 471 are controlled to operate synchronously. It has become. Specifically, the reception-only switch 471 is controlled to be in a cutoff state when the switch control signal is at the first level (transmission side), and to be in the conduction state when it is at the second level (reception side). Thereby, the signal system can be further simplified, and when the transmitter/receiver switch 451 is in the reception connection state, the reception-only switch 471 can be reliably set to the cutoff state.

FIG. 3 is a block diagram showing an example of the electrical configuration of the UE (mobile terminal device) 5. As shown in FIG. UE5 is configured as a smartphone including microcomputer 100 as a processing entity. The microcomputer 100 includes a CPU 101, a RAM 102 serving as a program execution area, a ROM 103, an input/output section 104, a bus 106 interconnecting them, and the like. Further, a flash memory 105 is connected to the bus 106, in which an OS 105s for constructing an operating environment for the UE 5, communication firmware 105a including an LTE protocol stack for the UE, and the like are installed.

Further, a monitor 109 is connected to the input/output unit 104 via a graphic controller 1091. A touch panel 110 serving as an input unit is superimposed on the monitor 109, and in cooperation with various software operation units displayed on the monitor 109, various information necessary for controlling the operation of the UE 5 can be input. There is. The monitor 109 functions as a means for reproducing moving images (videos) etc. distributed via a public broadband communication system. Touch panel 110 is connected to input/output section 104 via touch panel controller 1101. A camera 111 for taking still images or moving images is connected to the input/output unit 104. Furthermore, a wireless communication section 500 is connected to the bus 106. The UE 5 is wirelessly connected to the radio base station section 4 of the radio communication unit 1 shown in FIG. The electrical configuration of the wireless communication unit 500 corresponds to, for example, the wireless communication unit 412 of the wireless base station unit 4 in FIG. 4 by removing the receive diversity function portion including the receive-only antenna 105B, but it is also a well-known configuration. A detailed explanation will be omitted.

An overview of the LTE communication system will be described below.
FIG. 7 is a schematic diagram showing the structure of an IP packet used for data transmission between the UE 5 and the portable base station device 1. The IP packet 1300 consists of an IP header 1301 and a payload 1302, and a PDU identification number, a data source address 1301a, a destination address 1301b, and the like are written in the IP header 1301.

8 and 9 show wireless protocol stacks in the LTE system, FIG. 8 shows a user plane protocol stack, and FIG. 9 shows a control plane protocol stack. The wireless protocol stack is divided into layers 1 to 3 of the OSI reference model, with layer 1 being the PHY (physical) layer. Layer 2 includes a MAC (Medium Access Control) layer, an RLC (Radio Link Control) layer, and a PDCP (Packet Data Convergence Protocol) layer. Layer 3 includes an RRC (Radio Resource Control) layer and a NAS (Non-Access Stratum) layer.

The role of each layer is as follows.
- PHY layer: performs encoding/decoding, modulation/demodulation, antenna mapping/demapping, and resource mapping/demapping. Data and control signals are transmitted between the PHY layer of the UE 5 and the relay radio communication unit 9 and the PHY layer of the radio base station unit (eNodeB) 4 via a physical channel.
- MAC layer: Performs data priority control, HARQ retransmission control processing, random access procedures, etc. Data and control signals are transmitted between the MAC layer of the UE 5 and the MAC layer of the radio base station section 4 via a transport channel. The MAC layer of the radio base station unit 4 includes a scheduler that determines uplink and downlink transport formats (transport block size, modulation and coding scheme (MCS)) and resource blocks to be allocated to the UE 5.

- RLC layer: transmits data to the RLC layer on the receiving side using the functions of the MAC layer and PHY layer. Data and control signals are transmitted between the RLC layer of the UE 5 and the RLC layer of the radio base station section 4 via logical channels.
- PDCP layer: Performs header compression/decompression, encryption/decryption of PDU.
- RRC layer: Defined only in the control plane that handles control signals. Messages for various settings (RRC messages) are transmitted between the RRC layer of the UE 5 and the RRC layer of the radio base station section 4. The RRC layer controls logical, transport and physical channels according to the establishment, re-establishment and release of radio bearers. If there is a connection (RRC connection) between the RRC of the UE5 and the RRC of the radio base station unit 4, the UE5 is in RRC connected mode, otherwise it is in RRC idle mode.

The above layers are used in both the control plane and the user plane. On the other hand, only in the control plane, the UE 5 and the MME 2 are provided with a NAS layer that performs session management, mobility management, etc. higher than the RRC layer. Further, a user data transmission interface between the radio base station section 4 and the EPC function section 3 side is provided with a GTP-U (GPRS (General Packet Radio Service) Tunneling Protocol for User Plane) layer. The GTP-U layer is for identifying the UE 5 to be connected and the radio bearer to be used.

Next, FIG. 10 shows downlink channel mapping in the LTE system. Here, a mapping relationship between a logical channel (Downlink Logical Channel), a transport channel (Downlink Transport Channel), and a physical channel (Downlink Physical Channel) is shown. Below, they will be explained in order.
- DTCH (Dedicated Traffic Channel) is a dedicated logical channel for data transmission. DTCH is mapped to DLSCH (Downlink Shared Channel), which is a transport channel.
- DCCH (Dedicated Control Channel): A logical channel for transmitting dedicated control information between the UE 5 and the network. DCCH is used when the UE 5 has an RRC connection with the radio base station section 4. DCCH is mapped to DLSCH.
- CCCH (Common Control Channel): A logical channel for transmitting control information between the UE 5, the relay radio communication section 9, and the radio base station section 4. CCCH is used when UE 5 does not have an RRC connection with radio base station section 4. CCCH is mapped to DLSCH.

- BCCH (Broadcast Control Channel): A logical channel for distributing system information. The BCCH is mapped to a BCH (Broadcast Channel) or DLSCH, which is a transport channel.
- PCCH (Paging Control Channel): A logical channel for notifying paging information and system information changes. The PCCH is mapped to a PCH (Paging Channel), which is a transport channel.

Further, the mapping relationship between transport channels and physical channels is as follows.
- DLSCH and PCH: mapped to PDSCH (Physical Downlink Shared Channel). DLSCH supports HARQ, link adaptation, and dynamic resource allocation.
- BCH: Mapped to PBCH (Physical Broadcast Channel).

Next, FIG. 11 shows uplink channel mapping in the LTE system. Similar to FIG. 8, the mapping relationship between the logical channel (Downlink Logical Channel), the transport channel (Downlink Transport Channel), and the physical channel (Downlink Physical Channel) is shown. Below, they will be explained in order.
- CCCH (Common Control Channel): A logical channel used to transmit control information between the UE 5 and the EPC function unit 3, and a logical channel used to transmit control information between the EPC function unit 3 and radio resource control (RRC). Control) used by UE5s that do not have a connection.
・DCCH (Dedicated Control Channel): A point-to-point bidirectional logical channel, used to transmit individual control information between the UE 5 and the EPC function unit 3. This is a channel for The dedicated control channel DCCH is used by UE5s that have an RRC connection.
- DTCH (Dedicated Traffic Channel): A one-to-one bidirectional logical channel, which is dedicated to a specific UE or relay radio communication unit, and is used to transfer user information.

- It is a transport channel that supports ULSCH (Uplink Shared Channel: HARQ), dynamic adaptive radio link control, and discontinuous transmission (DTX).
- RACH (Random Access Channel): A transport channel on which limited control information is transmitted.

- PUCCH (Physical Uplink Control Channel): Response information for downlink data (ACK (Acknowledge)/NACK (Negative acknowledge)), downlink radio quality information (CQI: Channel Quality Indicator), and This is a physical channel used to notify the wireless base station section 4 of a request for transmission of uplink data (scheduling request: SR).
- PUSCH (Physical Uplink Shared Channel): A physical channel used to transmit uplink data.
- PRACH (Physical Random Access Channel): A physical channel mainly used for random access preamble transmission to obtain transmission timing information (transmission timing command) from the UE 5 to the radio base station section 4. Random access preamble transmission is performed during the random access procedure.

As shown in FIG. 11, in the uplink, transport channels and physical channels are mapped as follows. The uplink transmission and reception channel ULSCH is mapped to the physical uplink transmission and reception channel PUSCH. Random access channel RACH is mapped to physical random access channel PRACH. The physical uplink control channel PUCCH is used as a physical channel alone. Further, the common control channel CCCH, dedicated control channel DCCH, and dedicated traffic channel DTCH are mapped to the uplink transmission and reception channel ULSCH.

Next, in the downlink of the LTE system, the UE 5 wirelessly connects to the radio base station section 4 using OFDM (Orthogonal Frequency-Division Multiplexing) access (OFDMA). The OFDMA system is characterized as a two-dimensional multiple access system that combines frequency division multiplexing and time division multiplexing. Specifically, orthogonal subcarriers on the frequency axis and time axis are divided and allocated to UE5, and the subcarriers that are orthogonal on the frequency axis are divided so that the signal of each subcarrier becomes zero (0 point). . By dividing subcarriers and allocating them on the frequency axis, even if one subcarrier is affected by fading, it is possible to select another subcarrier that is unaffected. This has the advantage that subcarriers can be used and wireless quality can be maintained.

In the OFDMA system, a resource block (hereinafter also referred to as RB) defined on a virtual plane extending between a frequency axis and a time axis is employed as a radio resource. As shown in FIG. 12, RB is defined as a block in which the above plane is divided into a matrix at 180 kHz/0.5 msec, and each resource block RB divides 12 adjacent subcarriers at 15 kHz intervals on the frequency axis, on the time axis. In the above example, one slot of the frame (7 symbols) is included. These RBs are assigned to the UE 5 as a set of two adjacent RBs (1 msec) on the time axis. On the other hand, in the uplink of the LTE system, resource blocks RB having a similar concept are used as radio resources, except that SC-FDM (Single Career Frequency-Division Multiplexing) access (SC-FDMA) is adopted. In OFDMA, one resource block is divided into 12 subcarriers (bandwidth: 15 kHz) on the frequency axis, whereas SC-FDMA is a single carrier system in which division into subcarriers is not performed.

For example, allocation of resource blocks to the downlink is determined using the following procedure in the normal LTE protocol. The UE 5 and the relay radio communication unit 9 receive the CQI reference signal transmitted from the eNodeB 4 for each predetermined frequency unit, measure the CQI, which is an indicator indicating the reception quality of the downlink channel, and create CQI information. . CQI information expresses the reception quality obtained through measurement using two parameters: coding rate and frequency utilization efficiency for each modulation method, and is transmitted from UE5 to eNodeB4 using the uplink control channel (PUCCH described above). Reported using CQI index. The eNodeB4 allocates resource blocks to radio bearers with individual UE5s based on the CQI information notified from the plurality of UE5s. By optimally allocating a frequency block with a high received signal level to each UE5 according to the content of the CQI information of each UE5, it is possible to obtain a diversity effect (multi-user diversity) of the UE5, and improve user throughput and Throughput per cell can be improved.

When the portable base station device 1 is used in the transmission mode shown in FIG. A signal current is about to flow through the low noise amplifier 473. In the case of a general radio base station device used in a mobile communication system, the transmission output thereof is, for example, about 200 mW (+23 dBm) in the case of a radio base station device for TD-LTE. As shown in FIG. 13, when trying to set the interval DA between the transmitting/receiving antenna 105A and the receiving antenna 105B to a suitable half wavelength from the viewpoint of improving the gain of the array antenna and preventing side lobes, the frequency band used is, for example, GHz. In the case of the 800 MHz band, which is close to the band, the antenna spacing DA is about 37 cm. For example, if the antenna spacing DA is set to about 30 cm, which is slightly smaller than this, the free space propagation loss between both antennas will be about 20 dBm, and the input power of the transmitted wave going around to the receiving side will be 23-20 = 3 dBm (however, the antenna gain is ignored). This value is sufficiently smaller than the rated input upper limit value of the second low-noise amplifier 473 (for example, +23 dBm in the case of the above-mentioned commercial product), and there is almost no risk of damage.

However, in the case of this embodiment, the portable base station device 1 is used in a public broadband mobile communication system to which a frequency band ranging from 172.5 MHz to 202.5 MHz is allocated, and is not intended for long-distance transmission. The transmission wave power is set to a very large value of 5 W (37 dBm) or more. In the case of the 200 MHz band, the antenna spacing DA corresponding to a half wavelength is about 75 cm, but the free space propagation loss between the antennas in this case is calculated to be only about 16 dBm, and the input power of the transmitted wave that goes around to the receiving side is 37 cm. -16=21 dBm, which is a value quite close to the upper limit of the rated input of the second low noise amplifier 473. In this situation, there is a good possibility that an input exceeding the upper limit value of the second low-noise amplifier 473 will occur depending on the instantaneous value of the transmitted wave power, and the second low-noise amplifier 473 may be damaged. In particular, due to the antenna installation space, when the antenna spacing DA becomes closer, for example, when DA becomes about 50 cm, the free space propagation loss between the antennas becomes 37-12 = 25 dBm, and the second low noise amplifier 473 becomes stationary. As a result, the second low-noise amplifier 473 is exposed to an excessive input, and the possibility that the second low-noise amplifier 473 is damaged becomes even higher.

However, according to the configuration of the portable base station device 1 described above, as shown in FIG. Switch control is performed so that when the side switch unit 451 is in the transmission connection state, the reception-only switch 471 is in the cutoff state. Thereby, even if the transmission wave is transmitted with high power as described above, it is possible to effectively protect the second high frequency low noise amplifier 473 from damage caused by the wraparound reception to the receive-only antenna 105B. For example, this is particularly effective when the antenna spacing DA cannot be set sufficiently large due to installation space or the like, for example, when the antenna spacing DA must be set to a value smaller than a half wavelength of the transmitted wave.

Although the embodiments of the present invention have been described above, they are merely examples, and the present invention is not limited thereto. Various modified embodiments of the present invention will be described below. In FIG. 15, the transmission/reception side switch section 451 and the reception-only side switch 471 can be configured to be operated and controlled independently by mutually different switch control signals 1 and 2. In this case, a control form is adopted in which the timing for switching between the reception side and the transmission side of the transmission/reception side switch unit 451 using switch control signal 1 and the timing for switching conduction/cutoff of reception-only antenna 105B using switch control signal 2 are synchronized. It is possible to do so.

On the other hand, as shown in FIG. 16, for example, a control form is adopted in which the timing τ1 at which the transmitter/receiver side switch unit 451 switches from reception to transmission is delayed by a certain period of time with respect to the timing τ0 at which the reception-only switch 471 switches from conduction to cutoff. You can also do that. When the transmission/reception side switch section 451 and the reception-only side switch 471 are configured with high-frequency transistor modules, a certain transition period exists in the on/off switching of the high-frequency transistors. As a result, as shown in FIG. 4, if the switching timings of the transmitting/receiving side switch section 451 and the receiving-only side switch 471 are the same, when the transmitting/receiving side switch section 451 switches to the transmitting side, the above-mentioned transitions of both switches will occur. Due to the overlap of the periods, the reception-only switch 471 may momentarily maintain a conductive state, which may cause excessive input to the second high-frequency low-noise amplifier 473. However, such problems can be effectively prevented by delaying the timing τ1 as described above.

Also, instead of configuring the transmitting/receiving side switch section 451 with an SPST switch as shown in FIG. 4, the transmitting/receiving side switch section 451' is configured with a pair of SPST switches provided separately on the transmitting side and the receiving side, as shown in FIG. It is also possible to configure it with 451t and 451r. In this case, the binary switch control signal is inverted and distributed to one of the SPST switches 451t and 451r by the inverter 451i. Alternatively, as shown in FIG. 18, switch switching control may be performed by inputting switch control signal 1 to SPST switch 451t, and distributing and inputting switch control signal 2 to SPST switch 451r and reception-only switch 471. .

1 Portable base station device 2 MME
3 EPC function section 4 Radio base station section 5 UE (terminal device)
6 S-GW
7 P-GW
8 Router 21 Secondary battery module 22 Power supply circuit section 23 Portable housing 50 Wireless communication system 57 Radio bearer 105A Transmission/reception antenna 105B Reception-only antenna 301 CPU
302 RAM
303 Mask ROM
305 Flash memory 305a Communication firmware 305b MME entity 305c S-GW entity 305d P-GW entity 306 Bus 401 CPU
402 RAM
403 Mask ROM
404 Communication interface 405 Flash memory 405a Communication firmware 405b Switch switching control firmware 406 Bus 450 Wireless communication section 451 Transmission/reception side switch section 453 Transmission side power amplifier 463 First high frequency low noise amplifier 471 Reception only side switch 473 Second high frequency low noise amplifier

Claims (6)

a modulation/demodulation circuit that modulates the transmitted wave and demodulates the received wave;
transmitting and receiving antenna,
a transmitting side power amplifier that amplifies a transmitted wave signal and outputs it to the transmitting and receiving antenna;
a first high frequency low noise amplifier that amplifies a received wave signal received by the transmitting/receiving antenna and outputs it to the modulation/demodulation circuit;
It is provided on a connection path between the transmitting and receiving antenna, the transmitting side power amplifier, and the first high frequency low noise amplifier, and is insulated and cut off from the transmitting side power amplifier, while being electrically connected to the first high frequency low noise amplifier. and a transmission connection state in which the electrical connection state of the transmitting and receiving antenna is electrically connected to the transmitting side power amplifier, but insulated and disconnected from the first high frequency low noise amplifier. A transmitter/receiver switch section that switches between
a reception-only antenna that forms a diversity reception section together with the transmission and reception antenna;
a second high-frequency low-noise amplifier that amplifies the received wave signal received by the receive-only antenna and inputs the amplified signal to the modulation/demodulation circuit;
a reception-only side that is provided between the second high-frequency low-noise amplifier and the reception-only antenna, and switches a connection state between the reception-only antenna and the second high-frequency low-noise amplifier between a conductive state and a cutoff state; switch and
When the transmitting/receiving side switch unit is in the receiving connection state, the reception-only switch is in the conducting state, and when the transmitting/receiving switch unit is in the transmitting connection state, the receiving-only switch is in the cutoff state. In this way, the operation of the transmitting/receiving side switch unit and the receiving only side switch is controlled, and the timing at which the transmitting/receiving side switch unit switches from receiving to transmitting is set relative to the timing at which the receiving only side switch switches from conduction to cutoff. , a switch control unit that delays for a certain period of time ;
A wireless base station device comprising: 2. The radio base station apparatus according to claim 1, wherein the second high frequency low noise amplifier has an input upper limit of 25 dBm or less, and the transmitter side power amplifier has a transmission output of 4 W or more. The radio base station device according to claim 2, which is used in a public broadband mobile communication system to which a frequency band ranging from 172.5 MHz to 202.5 MHz is allocated. The transmitting/receiving side switch section is configured as an SPDT switch that selectively connects the transmitting/receiving antenna to the transmitting side power amplifier and the first high frequency low noise amplifier,
4. The reception-only side switch is configured as an SPST switch provided on an input path from the reception-only antenna to the second high-frequency low-noise amplifier. Wireless base station equipment. The switch control unit controls the synchronous operation of the transmission/reception side switch unit and the reception-only switch by distributing and inputting a switch control signal to the transmission/reception side switch unit to the reception-only switch. The radio base station apparatus according to any one of claims 1 to 4. A wireless network system that performs mobile communication between a wireless base station device and a mobile terminal device wirelessly connected to the wireless base station device, the wireless base station device comprising:
a modulation/demodulation circuit that modulates the transmitted wave and demodulates the received wave;
transmitting and receiving antenna,
a transmitting side power amplifier that amplifies a transmitted wave signal and outputs it to the transmitting and receiving antenna;
a first high frequency low noise amplifier that amplifies a received wave signal received by the transmitting/receiving antenna and outputs it to the modulation/demodulation circuit;
It is provided on a connection path between the transmitting and receiving antenna, the transmitting side power amplifier, and the first high frequency low noise amplifier, and is insulated and cut off from the transmitting side power amplifier, while being electrically connected to the first high frequency low noise amplifier. and a transmission connection state in which the electrical connection state of the transmitting and receiving antenna is electrically connected to the transmitting side power amplifier, but insulated and disconnected from the first high frequency low noise amplifier. A transmitter/receiver switch section that switches between
a reception-only antenna that forms a diversity reception section together with the transmission and reception antenna;
a second high-frequency low-noise amplifier that amplifies the received wave signal received by the receive-only antenna and inputs the amplified signal to the modulation/demodulation circuit;
a reception-only side that is provided between the second high-frequency low-noise amplifier and the reception-only antenna, and switches a connection state between the reception-only antenna and the second high-frequency low-noise amplifier between a conductive state and a cutoff state; switch and
When the transmitting/receiving side switch unit is in the receiving connection state, the reception-only switch is in the conducting state, and when the transmitting/receiving switch unit is in the transmitting connection state, the receiving-only switch is in the cutoff state. In this way, the operation of the transmitting/receiving side switch unit and the receiving only side switch is controlled, and the timing at which the transmitting/receiving side switch unit switches from receiving to transmitting is set relative to the timing at which the receiving only side switch switches from conduction to cutoff. , a switch control unit that delays for a certain period of time ;
A wireless network system comprising:

Images