JP7357493B2 - Mobile terminal equipment and wireless network system - Google Patents

Description

The present invention relates to a mobile terminal device and a wireless network system using the same, and particularly to a mobile terminal device and a wireless network system suitable for a public broadband mobile communication system using the VHF band.

Traditionally, public communication systems used by the national and local governments, police, fire departments, and emergency services at disaster sites have mainly been voice-based. 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.

Ministry of Land, Infrastructure, Transport and Tourism Public Broadband Mobile Communication System Standard Specifications (Kokuden Tsusho No. 56 (established February 8, 2016))

By the way, if we look at the state of radio wave use in Japan around the 200 MHz band used by the above-mentioned public broadband mobile communication system, the situation is as shown in Fig. 13. The 12 channels of analog television broadcasting were allocated to the VHF band from 90 MHz to 222 MHz, but not all of that band was used for analog television broadcasting, and the middle band from 108 to 170 MHz was allocated to the 150 MHz mobile band. It is assigned to radio and broadcasting business communication radio. On the other hand, the upper limit frequency of the 200MHz band used by public broadband mobile communication systems adjacent to the high frequency side is 202.5MHz, and there is only one channel width between it and the 220MHz band used for multimedia broadcasting. A corresponding guard band of 5 MHz is ensured. Communication radios for broadcasting business are used as a means of communication during emergency reporting and program production.Especially in the event of a disaster, news crews can communicate with helicopters conducting aerial reporting, or they can communicate with reporting sites all at once. It has been positioned as an essential part of the process. As can be seen from this application, public broadband mobile communication systems and broadcasting business contact radios are very similar in their uses and timing of use, and communication traffic congestion for both systems may occur at the same time, especially in the event of an emergency disaster. is high.

The problem here is the relationship between the lower limit frequency (172.5 MHz) of the allocated band for public broadband mobile communications and the upper limit frequency (170 MHz) of the allocated band for broadcasting business contact radio. A blank band of only 2.5 MHz, which is half of the guard band, is provided. As a result, channels on the lower limit frequency side of the 200 MHz band used by public broadband mobile communications are extremely susceptible to interference with the communication waves of broadcasting service contact radios, making normal communication difficult. As a result, at present, public broadband mobile communication systems are currently only using the three channels on the upper frequency range of the six channels set in the 200MHz band, and radio wave resources are not being used effectively. It's hard to say.

An object of the present invention is to provide a public broadband mobile communication system that can effectively suppress interference waves from other station frequency bands adjacent to the lower limit frequency side of the 200 MHz band, and that can effectively utilize radio wave resources in the 200 MHz band. An object of the present invention is to provide a mobile terminal device and a wireless communication system using the same.

In order to solve the above problems, a mobile terminal device according to the present invention is used in a public broadband mobile communication system, and includes a transmitting/receiving antenna and a transmitting front end section switchably connected to the transmitting/receiving antenna via an antenna switch. and a reception front-end section; and a modulation/demodulation circuit that is connected to the wireless front-end circuit and performs modulation of transmitted waves and demodulation of received waves, the mobile terminal device comprising: a reception front-end section; It is configured as a bandpass filter whose pass band includes the allocated frequency band for public broadband mobile communication from 172.5 MHz to 202.5 MHz, and the frequency band from 160 MHz to 170 MHz adjacent to the lower limit frequency side of the allocated frequency band. A low- frequency side interference wave cutting filter is provided to block the communication waves of communication radio for broadcasting business using , as low-frequency side interference waves , and the allocated frequency band covers the entire allocated frequency band. In this case, six channels with a bandwidth of 5 MHz are set, and the channel whose lower limit frequency of the assigned frequency band matches the channel lower limit frequency is set as the first channel, and the resource block is set in the frequency band of the first channel. Among them, the LTE communication terminal is configured as an LTE communication terminal that performs communication using the lowest frequency resource block whose block lower limit frequency matches the channel lower limit frequency, and the lower frequency side interference wave cutoff filter has an attenuation amount of 25 dB or more at 170 MHz. It is configured as a SAW filter of 70 dB or less, and the SAW filter has an insertion loss of 5 dB or more and 15 dB or less in the passband. A main low-noise amplifier for amplification is provided, and a compensation low-noise amplifier is further provided on the output side of the SAW filter to compensate for the insertion loss of the received wave signal due to the SAW filter by amplifying the received wave signal after passing through the SAW filter. It is characterized by being

Further, the wireless network system of the present invention performs public broadband mobile communication in the allocated frequency band from 172.5 MHz to 202.5 MHz between mobile terminal devices wirelessly connected to the wireless base station section of the portable base station device. A wireless network system characterized in that a mobile terminal device is constituted by the mobile terminal device of the present invention.

The mobile terminal device has six channels set in the allocated frequency band with a bandwidth of 5 MHz to cover the entire allocated frequency band, and selects a channel whose lower limit frequency of the allocated frequency band matches the channel lower limit frequency. As the first channel, the LTE communication terminal can be configured as an LTE communication terminal that performs communication using the lowest frequency resource block whose block lower limit frequency matches the channel lower limit frequency among the resource blocks set in the frequency band of the first channel. can. In this case, the wireless network system of the present invention can be configured to include an EPC (Evolved Packet Core) function section that is connected by wire to the wireless base station section and functions as an upper network control section for the wireless base station section. Then, the radio base station section sets the channel whose lower limit frequency of the allocated frequency band matches the channel lower limit frequency as the first channel, and among the resource blocks set in the frequency band of the first channel between the radio base station section and the LTE communication terminal, The radio bearer can be constructed using the lowest frequency resource block whose block lower limit frequency matches the channel lower limit frequency.

The mobile terminal device and wireless communication system of the present invention provide a reception front end section of the mobile terminal device with a frequency band from 160 MHz adjacent to the lower limit frequency side (172.5 MHz) of the 200 MHz band, which is the allocated frequency band of the public broadband mobile communication system. A low-frequency side interference wave blocking filter is provided to block communication waves in a frequency band up to 170 MHz as low-frequency side interference waves. As a result, when building a public broadband mobile communication system in the 200MHz band, it is possible to effectively eliminate the problem of radio wave interference caused by communication waves of other stations in the above band on the lower limit frequency side (specifically, communication waves of communication radio for broadcasting business). Therefore, it is possible to effectively utilize radio wave resources in the 200 MHz band.

FIG. 1 is a block diagram showing an overview of the configuration of a wireless communication system according to the present invention. FIG. 2 is a block diagram showing an example of an electrical configuration of a portable base station device. FIG. 1 is a block diagram showing an example of the electrical configuration of a mobile terminal device of the present invention. FIG. 2 is a block diagram showing the electrical configuration of a wireless communication unit of a mobile terminal device. 5 is a graph showing the pass characteristics of the SAW filter used in the embodiment. FIG. 4B is a block diagram showing an example of an electrical configuration of a modulation section of the wireless communication section in FIG. 4A. FIG. 4B is a block diagram showing an example of an electrical configuration of a demodulation section of the wireless communication section in FIG. 4A. 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. 2 is an explanatory diagram showing the communication frequency allocation status of the VHF band.

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 includes a wireless base station (eNodeB (evolved wireless base station)) 4 and an EPC (evolved Packet Core) functional unit 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 dashed-dotted arrow lines. There is.

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 communication firmware 405a including an LTE protocol stack for wireless base stations is stored therein. 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.

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. 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.

FIG. 4A is a block diagram showing an example of the electrical configuration of wireless communication section 500. The wireless communication unit 500 includes an interface unit 501 for inputting and outputting digital signals with the bus 106 of the microcomputer hardware shown in FIG. An antenna switch 504 that selectively connects the receiving block 510 and the transmitting block 550 to the transmitting block 550, the transmitting/receiving antenna 505, and the transmitting/receiving antenna 505 in response to a transmitting/receiving switching signal from the microcomputer hardware side. Equipped with. The receiving block 510 and the transmitting block 550 individually support multiple modulation and demodulation schemes for performing adaptive modulation, such as QPSK (Quadrature Phase shift Keying), 16QAM (16Quadrature Amplitude Modulation), or 64QAM (16Quadrature 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 transmission side block 550 includes a modulation circuit 700 that generates an analog transmission wave signal by modulating a carrier wave using a serial transmission data signal inputted from the interface section 501 as a baseband signal, and a modulation circuit 700 that generates an analog transmission wave signal by amplifying the analog transmission wave signal and transmitting and receiving it. It includes a transmission front end section 730 that supplies the antenna 505. In addition, the reception side block 510 includes a reception front end section 630 that extracts and amplifies a desired wave from the antenna reception signal, and a reception front end section 630 that demodulates a baseband signal from the reception wave signal outputted from the reception front end section 630 and converts it into serial reception data. A demodulation circuit 600 for converting is provided. The transmission front end section 730 and the reception front end section 630 constitute a wireless front end circuit. Furthermore, the modulation circuit 700 and the 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 to a transmission front end section 730 (FIG. 4A).

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. 4A. 501.

Returning to FIG. 4A, the transmission front end unit 730 amplifies the analog transmission wave signal from the modulation circuit 700 with the power amplifier 553, passes it through the bandpass filter 552, and outputs it as a transmission wave via the antenna switch 504 and antenna 505. do. On the other hand, reception front end section 630 amplifies the reception wave received by antenna 505 using main low noise amplifier 513, passes it through bandpass filter 511, and outputs it to demodulation circuit 600 as an analog reception wave signal.

The bandpass filter 511 is configured so that its pass band includes the 200 MHz band (172.5 MHz to 202.5 MHz: allocated frequency band for public broadband mobile communications) shown in FIG. The lower limit frequency side (172.5 MHz) of the 200 MHz band is adjacent to the allocated frequency band (160 MHz to 170 MHz) for communication radio for broadcasting business with a blank band of only 2.5 MHz in between. The bandpass filter 511 in FIG. 4A functions as a low-frequency side interference wave blocking filter that blocks communication waves of communication radio for broadcasting business as low-frequency side interference waves. As a result, when a public broadband mobile communication system is constructed in the 200 MHz band as described above, it is possible to effectively solve the deterioration of blocking characteristics due to interference waves originating from broadcasting business contact radio. Furthermore, due to the existence of these interference waves, the active use of the three low-frequency channels of the six channels in the 200 MHz band has been postponed in public broadband mobile communications. The three channels can be used without any problems, and the radio wave resources in the 200 MHz band can be used effectively.

As shown in Figure 13, the allocated frequency band for public broadband mobile communications has six channels (CH1 to CH6: center frequencies of 175, 180, 185, 190, 195, and 200 MHz, respectively) to cover the entire allocated frequency band. , the bandwidth is set to 5MHz each). The communication system 50 (FIG. 1) of this embodiment employing the LTE method is configured to be able to use all six channels, and the lower limit frequency (172.5 MHz) of the above-mentioned allocated frequency band matches the channel lower limit frequency. When CH1 (first channel) is used, all resource blocks set in the channel are used for communication (the control form will be described later). The lowest frequency resource block EB (FIG. 12) whose block lower limit frequency matches the channel lower limit frequency is also used for communication without being particularly distinguished from other resource blocks.

This lowest frequency resource block EB has the narrowest frequency interval with the allocated band of the communication radio for broadcasting business, and is most susceptible to interference waves. As mentioned above, the frequency interval is extremely narrow at 2.5 MHz, so the specifications of the band pass filter 511 are such that the desired wave on the public broadband mobile communication side is not excessively attenuated (for example, within 15 dB), and the frequency interval is 2.5 MHz. It is required to have a steep passage characteristic that can sufficiently attenuate (for example, 25 dB or more) communication waves of communication radio for broadcasting business that are far away on the low frequency side. However, the wavelength of communication waves in the 200 MHz band is as large as approximately 75 cm, and the size of a cavity filter that can obtain deep attenuation and steep passage characteristics, for example, becomes extremely large. It cannot be integrated into equipment.

Therefore, in this embodiment, a SAW (Surface Acoustic Wave) filter (hereinafter also referred to as SAW filter 511) is employed as the bandpass filter 511 (low-frequency side interference wave cutting filter) in FIG. 4A. The SAW filter has a structure in which comb-shaped electrodes are placed facing each other on a piezoelectric substrate, and the high-frequency signal input as an electric signal is generated by surface elasticity with a wavelength of about several μm on the surface layer due to the piezoelectric effect of the piezoelectric substrate. converted into waves. Then, a desired frequency component included in the surface acoustic wave is extracted as it propagates on the piezoelectric substrate, and this is extracted again as an electric signal. The passband width and center frequency of the filter can be adjusted in various ways depending on the structural period of the comb-shaped electrodes and the physical properties of the piezoelectric material and electrodes. By adopting the SAW filter, the bandpass filter 511 (low-side interference wave cutting filter) can be reduced to a size that can be incorporated into a mobile terminal device as a surface-mounted device, even in the frequency band with a large wavelength as described above. It is.

The SAW filter 511 preferably has an attenuation amount of 25 dB or more in the vicinity of 170 MHz, which corresponds to the upper limit frequency of the allocated band of the broadcast business contact radio. If the amount of attenuation at this frequency is less than 25 dB, the effect of blocking low frequency interference waves will not be sufficient. Although there is no particular restriction on the upper limit value of this attenuation amount, it is possible to set the upper limit value to about 70 dB, for example. On the other hand, it is desirable that the amount of attenuation at 172.5 MHz, which corresponds to the lower limit frequency of the 200 MHz band, be 15 dB or less. FIG. 4B is a graph showing the pass characteristics of the SAW filter used in this embodiment, and the attenuation characteristics at 170 MHz are steep at about 40 dB. By adopting the SAW filter 511 having such a deep and steep attenuation characteristic, it is possible to effectively improve the reception blocking characteristics (especially the reception characteristics of CH1 (center frequency: 175 MHz)) due to the transmission power of the contact radio for broadcasting business. .

When the SAW filter 511 as described above is employed, the amount of attenuation of the desired signal within the pass band becomes large, ranging from 5 dB to 15 dB (for example, 10 dB). On the other hand, background noise (mainly thermal noise, for example) with respect to the desired signal may remain at the same level without being attenuated even if it passes through the SAW filter 511. In this case, the NF (Noise Figure) of the desired signal may This creates an aggravating problem. Therefore, as shown in FIG. 4A, the above-mentioned main low noise amplifier 513 is installed between the antenna switch 504 and the SAW filter 511 (low frequency interference wave cutting filter) to amplify the received wave signal received by the transmitting/receiving antenna 505. On the output side of the SAW filter 511, a compensation low-noise amplifier 512 can be provided that compensates for the insertion loss of the received signal due to the SAW filter 511 by amplifying the received wave signal after passing through the SAW filter 511. By providing such a compensating low-noise amplifier 512, it is possible to compensate for the attenuation of the desired signal due to the insertion loss of the SAW filter 511, and it is possible to effectively solve the problem of deterioration of NF. The gain of the compensation low-noise amplifier 512 is preferably set to about 0.5 times or more and twice or less the insertion loss level of the SAW filter 511. Note that it is also possible to use a plurality of SAW filters with low attenuation rates connected in cascade.

Note that in the present invention, the bandpass filter constituting the low-frequency side interference wave blocking filter is not limited to the SAW filter, and for example, it is also possible to adopt a filter of other types with inferior steepness of pass characteristics. It is. In this case, for example, it will be difficult to avoid deterioration of blocking characteristics when CH1 (first channel) is adopted, but it is necessary to expand its use to CH2 or CH3 on the high frequency side, which have not been used for public broadband mobile communications. I can do it.

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.

As shown in FIG. 12, the above-mentioned scheduler operating on the MAC layer uses the wireless network in FIG. In constructing the bearer 57, resource block RB allocation control is performed using the method shown in FIG. In the radio base station section 4 of FIG. 3, based on the frequency specified by the resource block RB allocated by the scheduler, the carrier frequency and modulation method for the voltage control oscillation circuit VCO of the modulation section 700 and the demodulation section 600 in FIGS. 5 and 6 are determined. Setting instructions are given.

Even when CH1 is used, in which the lower limit frequency (172.5 MHz) of the allocated frequency band matches the channel lower limit frequency, the scheduler performs allocation scheduling by selecting all resource blocks set within the channel. Execute. In FIG. 12, even when the lowest frequency source block EB whose block lower limit frequency matches the channel lower limit frequency is allocated to construct the radio bearer 57, as already detailed, as shown in FIG. 4A, the receiving front end By providing the SAW filter 511 that serves as a low-frequency side interference wave blocking filter in the section 630, interference waves from the communication radio band for broadcasting business are effectively blocked, and high-quality reception at the UE 5 is enabled.

Although the embodiments of the present invention have been described above, they are merely examples, and the present invention is not limited thereto.

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 case 50 Wireless communication system 57 Radio bearer 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 406 Bus 412 Wireless communication section

Claims (3)

A wireless front end circuit used in a public broadband mobile communication system, comprising a transmitting/receiving antenna, a transmitting front end section and a receiving front end section switchably connected to the transmitting/receiving antenna via an antenna switch; A mobile terminal device comprising a modulation/demodulation circuit connected to a front end circuit and modulating a transmitted wave and demodulating a received wave,
The reception front-end section is configured as a bandpass filter whose passband includes the allocated frequency band for public broadband mobile communication ranging from 172.5 MHz to 202.5 MHz, and a bandpass filter that includes a bandpass filter that includes the allocated frequency band for the public broadband mobile communication from 172.5 MHz to 202.5 MHz, and A low- frequency side interference wave cutting filter is provided that blocks communication waves of contact radio for broadcasting business using the frequency band from 160 MHz to 170 MHz as low-frequency side interference waves ,
Six channels with a bandwidth of 5 MHz are set in the allocated frequency band to cover the entire allocated frequency band, and the channel whose lower limit frequency of the allocated frequency band matches the channel lower limit frequency is set as the first channel. , configured as an LTE communication terminal that performs communication using the lowest frequency resource block whose block lower limit frequency matches the channel lower limit frequency among the resource blocks set in the frequency band of the first channel,
The low frequency side interference wave blocking filter is configured as a SAW filter with an attenuation amount of 25 dB or more and 70 dB or less at 170 MHz,
The SAW filter has an insertion loss in the passband of 5 dB or more and 15 dB or less,
A main low-noise amplifier is provided between the antenna switch and the low-frequency interference wave blocking filter, and further includes a main low-noise amplifier that amplifies the received wave signal received by the transmitting and receiving antenna.
A compensation low-noise amplifier is provided on the output side of the SAW filter to compensate for the insertion loss of the received wave signal due to the SAW filter by amplifying the received wave signal after passing through the SAW filter. mobile terminal equipment. In a wireless network system that performs public broadband mobile communication in the allocated frequency band from 172.5 MHz to 202.5 MHz between mobile terminal devices wirelessly connected to a wireless base station section of a portable base station device,
The mobile terminal device includes a wireless front end circuit including a transmitting/receiving antenna, a transmitting front end section and a receiving front end section that are switchably connected to the transmitting/receiving antenna via an antenna switch, and the wireless front end circuit. and a modulation/demodulation circuit connected to the circuit for modulating the transmitted wave and demodulating the received wave. A low-frequency side interference wave blocking filter is provided to block communication waves of communication radio for broadcasting business using the frequency band from 160 MHz to 170 MHz adjacent to the lower limit frequency side of the system as low-frequency side interference waves. ,
Six channels with a bandwidth of 5 MHz are set in the allocated frequency band to cover the entire allocated frequency band, and the channel whose lower limit frequency of the allocated frequency band matches the channel lower limit frequency is set as the first channel. , configured as an LTE communication terminal that performs communication using the lowest frequency resource block whose block lower limit frequency matches the channel lower limit frequency among the resource blocks set in the frequency band of the first channel,
The low frequency side interference wave blocking filter is configured as a SAW filter with an attenuation amount of 25 dB or more and 70 dB or less at 170 MHz,
The SAW filter has an insertion loss in the passband of 5 dB or more and 15 dB or less,
A main low-noise amplifier is provided between the antenna switch and the low-frequency interference wave blocking filter, and further includes a main low-noise amplifier that amplifies the received wave signal received by the transmitting and receiving antenna.
A compensation low-noise amplifier is provided on the output side of the SAW filter to compensate for the insertion loss of the received wave signal due to the SAW filter by amplifying the received wave signal after passing through the SAW filter. wireless network system. The mobile terminal device is configured as an LTE communication terminal,
An EPC (Evolved Packet Core) functional unit is provided which is connected by wire to the wireless base station unit and functions as an upper network control unit for the wireless base station unit,
Six channels with a bandwidth of 5 MHz are set in the allocated frequency band so as to cover the entire allocated frequency band, and
The radio base station section sets a channel in which the lower limit frequency of the allocated frequency band matches the channel lower limit frequency as the first channel, and the radio base station section transmits a resource block configured in the frequency band of the first channel between the radio base station section and the LTE communication terminal. The radio network system according to claim 2 , wherein a radio bearer is constructed using the lowest frequency resource block whose block lower limit frequency matches the channel lower limit frequency.

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