JP2010187114A - Wireless communication system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To avoid an inefficient area design due to rainfall attenuation margin of a quasi-millimeter wave band/millimeter wave band FWA system. <P>SOLUTION: In a wireless communication system wherein a first base station connected to a network is connected to a user-side radio station via a first wireless line using a first frequency band, a second base station is provided, which is connected to the network and is connected to the radio station via a second wireless line using a second frequency band less attenuated by rainfall than the first frequency band, and the radio station includes: a means connected to the second base station via the second wireless line, a means for monitoring a reception signal intensity of a down link received via the first wireless line, and a means which performs communication of the down link and an up link via the first wireless line when the reception signal intensity exceeds a prescribed threshold and, in the case of the reception signal intensity equal to or lower than the prescribed threshold, performs communication of the down link via the first wireless line and performs communication of the up link via the second wireless line. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention combines a plurality of fixed wireless access (FWA) systems using different frequency bands, and when the communication quality of the first FWA system deteriorates due to rain or the like, The present invention relates to a wireless communication system and a wireless communication method for continuing communication with a second FWA system having a smaller rain attenuation than the FWA system as a bypass.

  For example, when the first FAW system is a fixed wireless access system using a quasi-millimeter wave band / millimeter wave band, the second FWA system is an IEEE802.11 wireless LAN or WiMAX using a microwave band. (World Interoperability for Microwave Access) A fixed wireless access system based on the standard.

  In order to provide a broadband Internet connection service, an optical line is spreading. However, laying an optical line is very expensive, and it is difficult to lay it unless a certain number of users can be expected. Therefore, in order to provide a broadband Internet connection service with reduced facility costs, a method of using a wireless line at a location closest to the user (last one hop) has been studied.

  As this last one-hop wireless line, a wireless LAN using a microwave band in which communication is possible without a line of sight between a base station on the network side and a terminal station on the user's home side has been studied. However, the user-friendly microwave band is also used in other wireless systems, and the frequency resources are severe. For example, IEEE802.11 wireless LAN using 2.4 GHz band can secure only 3 to 4 channels of 20 MHz band and is an ISM (Industrial Scientific and Medical) band. It will be used when signals are mixed. Similarly, although the 5 GHz band can be used, the service area is narrower than the 2.4 GHz band due to the frequency characteristics. In addition, IEEE802.11 wireless LAN is designed for wireless system parameters and is not assumed to be used outdoors in a wide area. Therefore, even when used outdoors, a service area with a radius of about 300 m is the limit. . On the other hand, a wireless system compliant with the WiMAX standard developed on the assumption of use in a wider area can generally secure a service area with a radius of about 3 to 5 km.

  In Japan, as a wireless system compliant with this WiMAX standard, the bandwidth for a wireless system used nationwide is 30 MHz (national band), and the bandwidth available in each region is 10 MHz for the purpose of eliminating regional digital divide. (Regional bands) have been allocated and preparations for actual services are underway. However, when expanding in terms of area, it is necessary to separate the frequency channels, and the 30 MHz band of the national band is also divided into 10 MHz units, and each channel is operated as a 10 MHz band. In this case, the throughput that can be provided is, for example, an upper limit of 20 to 30 Mbps shared by all users in an area with a radius of 3 km, and the throughput per user is insufficient for wideband applications such as video transmission. It will be a thing. Since this is a problem caused by the depletion of frequency resources in the microwave band, it is necessary to use a quasi-millimeter wave band or a millimeter wave band radio system rich in frequency resources for broadband wireless access. However, in this quasi-millimeter wave band / millimeter wave band radio system, large rain attenuation is often unavoidable at the time of rain, and it is necessary to secure a large rain attenuation margin at the time of circuit design.

FIG. 5 shows a configuration example of a conventional FWA (Fixed Wireless Access) system.
In the figure, a base station 102 connected to a network 101 and terminal stations 103a and 103b on the user's home side are connected via a wireless line. Terminal devices 105a and 105b are connected to the terminal station 103a via the router 104, and a terminal device 105c is connected to the terminal station 103b. Here, the terminal station 103a is assumed to be installed outdoors, and the terminal station 103b is assumed to be installed indoors.

  Between the base station 102 and the terminal stations 103a and 103b in such an FWA system is the above-mentioned “last one-hop” wireless line. For example, other wireless systems conforming to IEEE802.11 wireless LAN and WiMAX standards. In addition, a wireless system using a quasi-millimeter wave band / millimeter wave band such as 22 GHz, 26 GHz, 38 GHz, 60 GHz, or the like may be used.

FIG. 6 shows a configuration example of a conventional mobile radio access system.
In the figure, base stations 111a and 111b forming adjacent service areas 113a and 113b are connected to a network 101, respectively. The terminal station 112 moving between the service areas 113a and 113b is handed over to switch the connection destination from the base station 111a to the base station 111b. At this time, the routing information of the network is also switched.

  As described in Non-Patent Document 1, such a handover technique can be applied to handover between different types of mobile radio systems, and is discussed in the standardization of IEEE802.21 and the like. The key points of handover technology are (1) technology for mobile communication, (2) switching between uplink and downlink as a set, and (3) moving on the network for switching to maintain seamless communication. A function to perform management is necessary.

  The FWA system is based on the premise that the communication is stable, and there is no concept that different types of FWA systems coexist and are switched according to the communication state. However, even when different types of FWA systems are used, for example, when switching to the other FWA system when the communication quality of one FWA system deteriorates, it is possible to divert the mobile communication handover technique. However, in order to perform seamless handover, a communication line for exchanging various common control signals between different types of FWA systems is required, or complex protocols on a wide area network are processed. The function needs to be implemented.

  By the way, when using a quasi-millimeter wave band / millimeter wave band FWA system in order to cope with applications such as video transmission that require wide bandwidth in the downlink, there is no alternative wireless system with a wider band than that. A system configuration that assumes handover between FWA systems cannot be achieved. For this reason, when designing a quasi-millimeter-wave / millimeter-wave FWA system, a significant rain attenuation margin is expected for both uplink and downlink, and handover between different types of FWA systems is required. It becomes a single operation system configuration. As a result, although it is possible to set a wide serviceable area in fine weather, a narrow area is operated as a serviceable area in case of rain. For example, when the rainfall is about 50 mm / h in the 26 GHz band, the rain attenuation is about 9 dB per km. If the propagation loss with distance follows the third law, it means that the area radius that can be provided in fine weather is halved due to the rain attenuation margin. If the propagation loss associated with the distance is less than or equal to the third power law, such as when a line of sight can be expected, this corresponds to a further area reduction effect.

  In order to expand the service area in such an FWA system having a large rain attenuation margin, a method for increasing the transmission output is simple. However, although it is sufficient that the high power amplifier has a high output on the base station side, it is difficult in terms of cost to employ an expensive high power amplifier with high linearity for the terminal station on the user side. Therefore, the coverage area of the downlink from the base station side to the user side is wide, and the coverage area of the uplink from the user side to the base station side is narrow, and the service area is asymmetric between the downlink and the uplink. Therefore, the service area is substantially determined by the mounting specifications on the terminal side.

  In summary, if a mobile communication handover technique is used to switch between different types of FWA systems according to the communication state, a mechanism for that is required and the system configuration becomes complicated. On the other hand, when a quasi-millimeter wave band / millimeter wave band FWA system is used as one of different types of FWA systems, there is no alternative wireless system with a wider bandwidth than that, so that a wireless system corresponding to handover may be configured. Can not. Therefore, when trying to support only the quasi-millimeter wave band / millimeter wave band FWA system, the service area becomes asymmetric in the downlink and uplink, the service area is substantially determined according to the specifications of the terminal side, etc. Inefficient area design is inevitable.

  The present invention avoids the inefficient area design due to the rain attenuation margin of the quasi-millimeter wave band / millimeter wave band FWA system, and further enables the efficient area design by utilizing different types of FWA systems. It is an object to provide a system and a wireless communication method.

  In the first invention, a first base station connected to a network is connected to a user-side radio station via a first radio line using a first frequency band, and a downlink from the network to the radio station is performed. A wireless communication system that performs communication and uplink communication from a wireless station to a network via a first wireless line and a first base station is connected to the network and has a lower rain attenuation than the first frequency band. A second base station connected to the radio station via a second radio channel using two frequency bands, the radio station connecting to the second base station via the second radio channel; Means for monitoring the received signal strength of the downlink received via the first wireless line, and when the received signal strength exceeds a predetermined threshold, the communication of the downlink and the uplink is performed in the first wireless circuit. And means for performing downlink communication via the first wireless line and performing uplink communication via the second wireless line when the received signal strength is below a predetermined threshold. .

  In the second invention, a first base station connected to a network is connected to a wireless station via a first wireless line using the first frequency band, and the wireless station uses a third frequency band. The terminal station on the user side is connected via a wireless line, and downlink communication from the network to the wireless station and uplink communication from the wireless station to the network are performed via the first wireless line and the first base station. A second base station connected to a wireless station via a second wireless line that uses a second frequency band that is connected to the network and has a lower rain attenuation than the first frequency band. A radio station comprising: means for connecting to a second base station via a second radio channel; means for monitoring received signal strength of a downlink received via the first radio channel; Is prescribed When the threshold value is exceeded, downlink and uplink communication is performed via the first wireless line, and when the received signal strength is equal to or lower than a predetermined threshold value, downlink communication is performed via the first wireless line. And means for performing uplink communication via the second wireless line.

  In the wireless communication system of the first or second invention, the wireless station transmits an IP packet accommodated in a data packet to be transferred in uplink communication when the received signal strength is a predetermined threshold value or less. Means for encapsulating in another IP packet destined for the first base station and transferring it via a second radio channel, the first base station comprising: a second radio channel; a second base station; Means for terminating another IP packet transferred through the network, extracting the encapsulated IP packet, and sending the data packet to the network.

  In the wireless communication system of the first invention or the second invention, the first frequency band may be a quasi-millimeter wave band or a millimeter wave band. At this time, the second frequency band may be a microwave band, a UHF band, or a VHF band.

  In the wireless communication system of the second invention, the second wireless line may be a wireless line compliant with the WiMAX standard, and the third wireless line may be a wireless line compliant with the IEEE 802.11 wireless LAN standard.

  According to a third aspect of the present invention, a first base station connected to a network is connected to a user-side radio station via a first radio line using the first frequency band, and a downlink from the network to the radio station is performed. A wireless communication method for performing communication and uplink communication from a wireless station to a network via a first wireless line and a first base station is connected to the network and has a lower rain attenuation than the first frequency band. A second base station connected to the radio station via a second radio channel using the second frequency band, and the radio station includes means for connecting to the second base station via the second radio channel And monitoring the received signal strength of the downlink received via the first wireless line, and when the received signal strength exceeds a predetermined threshold, downlink and uplink communication via the first wireless line Performed, when the received signal strength is below a predetermined threshold value, to communicate downlink via the first radio network, and performs communication of the up link through the second wireless channel.

  According to a fourth invention, a first base station connected to a network is connected to a wireless station via a first wireless line using the first frequency band, and the wireless station uses a third frequency band. The terminal station on the user side is connected via a wireless line, and downlink communication from the network to the wireless station and uplink communication from the wireless station to the network are performed via the first wireless line and the first base station. A second base station connected to a wireless station via a second wireless line that uses a second frequency band that is connected to the network and has a lower rain attenuation than the first frequency band. And the wireless station includes means for connecting to the second base station via the second wireless line, monitors the downlink received signal strength received via the first wireless line, and the received signal strength is A predetermined threshold When the received signal strength is below a predetermined threshold, downlink communication is performed via the first wireless line, and downlink and uplink communication is performed via the first wireless line. Link communication is performed via a second wireless line.

  In the wireless communication method of the third or fourth aspect of the invention, the wireless station transmits an IP packet accommodated in a data packet to be transferred in uplink communication when the received signal strength is a predetermined threshold value or less. Encapsulated in another IP packet destined for the first base station and forwarded via the second radio link, the first base station via the second radio link, the second base station and the network Another IP packet transferred in this manner may be terminated, the encapsulated IP packet may be extracted, and the data packet sent out to the network.

  In the high-speed and wide-band FWA system using, for example, a quasi-millimeter wave band / millimeter-wave band, for example, by securing a radio line of a lower frequency, for example, a microwave band as an uplink detour, The circuit design avoiding the attenuation margin is possible, and the area design of the efficient FWA system can be performed. In addition, when configuring a network by combining different types of FWA systems, it is possible to perform local autonomous distributed judgment and processing without implementing a complicated protocol that realizes special control between different types of FWA systems. A wireless communication system can be easily constructed.

  Here, by using the quasi-millimeter wave band / millimeter wave band as the first wireless line, a high-speed and wide-band wireless line can be provided to many users on the downlink both in fine weather and during rainfall. On the other hand, by using any one of the microwave band, the UHF band, and the VHF band as the second wireless line, uplink communication can be ensured even during rain.

  In addition, the system can be reduced by using a wireless line conforming to the WiMAX standard as the second wireless line of the route for emergency evacuation when it rains, thereby enabling a single base station to cover a wide area. Can do. For the user side, a wireless line conforming to the IEEE802.11 wireless LAN standard, which has become cheaper due to the spread, is used as the second wireless line or the third wireless line. It is possible to provide a service for switching the uplink route during rainy weather and fine weather, while reducing the economic burden.

It is a figure which shows the structural example of Example 1 of the radio | wireless communications system of this invention. It is a figure which shows the structural example of Example 2 of the radio | wireless communications system of this invention. It is a figure which shows the structural example of Example 3 of the radio | wireless communications system of this invention. It is a figure which shows the structural example of Example 4 of the radio | wireless communications system of this invention. It is a figure which shows the structural example of the conventional FWA (fixed radio | wireless access) system. It is a figure which shows the structural example of the conventional mobile radio | wireless access system.

FIG. 1 shows a configuration example of Embodiment 1 of a wireless communication system of the present invention.
In the figure, a base station (# 1) 10 connected to a network 101 is connected to a radio station 30 on the user's home side via a first radio line 41. The base station (# 2) 20 connected to the network 101 is connected to the wireless station 30 on the user's home side via the second wireless line 42. A user terminal device (not shown) is connected to the radio station 30.

  Here, the first wireless line 41 is assumed to be a wireless line of an FWA system using a quasi-millimeter wave band / millimeter wave band, for example. As the second wireless line 42, for example, a wireless line of a wireless access system using a microwave band is assumed, and specifically, an IEEE 802.11 wireless LAN system or a wireless system based on the WiMAX standard is assumed. The example of the first wireless line 41 and the second wireless line 42 shown here focuses on the difference in rain attenuation characteristics and the amount of frequency resources. For example, for the frequency band of the first wireless line 41, Therefore, the frequency band of the second wireless line 42 only needs to be 1 GHz or more in frequency.

  In addition, the “millimeter wave band” shown in this specification is 30 GHz or more and 300 GHz or less, and the “quasi-millimeter wave band” is 10 GHz or more and less than 30 GHz, and rain attenuation is generally larger than the frequency band below that. The “microwave band” shown in this specification includes 1 GHz or more and less than 10 GHz including a frequency band called “quasi-microwave band”. Also, in the UHF band and VHF band (here, both of 30 MHz and less than 1 GHz combined) located below the microwave band, it is used in the communication field for reuse after the analog broadcast of a television is stopped. Therefore, the UHF band and the VHF band may be used as the second wireless line 42 and the third wireless line 43 shown in the third embodiment.

  The feature of the present invention is that the first radio channel 41 is used for the downlink during the rain while the second radio channel 42 having a small rain attenuation is used as the detour for the uplink, and both the downlink and the uplink are used during the fine weather. The first wireless line 41 can be used. As a result, it is possible to avoid inefficient area design due to the rain attenuation margin of the first radio line 41 that requires wide bandwidth.

The detailed configuration and operation of each station will be described below.
The base station (# 1) 10 has a base station function of the first radio line 41. The base station (# 2) 20 has a base station function of the second radio line 42.

  The radio station 30 includes a radio station radio function unit (# 1) 31 corresponding to the radio station function of the first radio channel 41 and a radio station radio function unit (# 2 corresponding to the radio station function of the second radio channel 42). ) 32, a routing unit 33, and a rain attenuation management unit 34. The radio station radio function unit (# 1) 31 monitors the received signal strength of the first radio line 41 and notifies the rain attenuation management unit 34 of the information. The rain attenuation management unit 34 compares the received signal strength with a predetermined threshold value, and controls the routing unit 33 according to the result as follows. If the received signal strength exceeds a predetermined threshold, an uplink data packet is output from the routing unit 33 to the radio station radio function unit (# 1) 31. If the received signal strength is less than or equal to a predetermined threshold, an uplink data packet is output from the routing unit 33 to the radio station radio function unit (# 2) 32. The routing unit 33 outputs the downlink data packet input from the radio station radio function unit (# 1) 31 to the user terminal device.

  Here, the operation of the wireless communication system according to the first embodiment will be described by dividing it into three patterns of downlink (common during sunny weather and rain), uplink (when sunny), and uplink (when raining).

(1) Downlink (common during fine weather and rain)
The downlink operation of the wireless communication system according to the first embodiment will be described. When a data packet addressed to the user is input from the network 101 to the base station (# 1) 10, the base station (# 1) 10 converts the data packet into a radio signal and transmits the radio station 30 via the first radio line 41. Send to. The radio station radio function unit (# 1) 31 of the radio station 30 receives the radio signal transmitted via the first radio line 41 and outputs it to the routing unit 33 as a data packet addressed to the user. The routing unit 33 outputs all data packets input from the radio station radio function unit (# 1) 31 to the user terminal device. The rain attenuation management unit 34 is not involved in the above operation, and the downlink is the same operation during fine weather and during rain.

(2) Uplink (when sunny)
The uplink operation in the clear day of the wireless communication system of the first embodiment will be described. When a data packet transmitted from the user terminal device toward the network 101 is input to the routing unit 33 of the wireless station 30, the routing unit 33 outputs the packet in a direction in accordance with the instruction from the rain attenuation management unit 34. Here, in the case of fine weather when the received signal strength of the radio station 30 exceeds a predetermined threshold value, the routing unit 33 sends the data packet to the radio station radio function unit (# 1) 31 in accordance with an instruction from the rain attenuation management unit 34. Output to. The radio station radio function unit (# 1) 31 converts the data packet into a radio signal and transmits the radio signal to the base station (# 1) 10 via the first radio line 41. The base station (# 1) 10 receives a radio signal transmitted via the first radio line 41 and outputs it to the network 101 as a data packet.

(3) Uplink (when raining)
The uplink operation during the rain of the wireless communication system according to the first embodiment will be described. When a data packet transmitted from the user terminal device toward the network 101 is input to the routing unit 33 of the wireless station 30, the routing unit 33 outputs the packet in a direction in accordance with the instruction from the rain attenuation management unit 34. Here, when it is raining when the received signal strength of the radio station 30 is equal to or less than a predetermined threshold, the routing unit 33 sends the data packet to the radio station radio function unit (# 2) 32 in accordance with an instruction from the rain attenuation management unit 34. Output. At this time, the routing unit 33 sets the destination MAC address of the data packet whose destination MAC address matches the MAC address of the wireless station wireless function unit (# 1) 31 to the wireless station wireless function unit (# 2). ) Rewrite to 32 MAC addresses. The radio station radio function unit (# 2) 32 converts the data packet into a radio signal and transmits it to the base station (# 2) 20 via the second radio line. The base station (# 2) 20 receives the radio signal transmitted via the second radio line 42 and outputs it to the network 101 as a data packet.

  In the network 101, it is possible to set a route to a server or the like as a communication partner of the user terminal device by referring to an IP address or the like given to a data packet to be transferred in a normal routing process. A new function related to the difference between the wireless lines 41 and 42 is not particularly required in the terminal 101.

  With the above control function, between the radio access system using the first radio channel 41 and the radio access system using the second radio channel 42, all control signals and complicated protocol processing are performed in the uplink. Therefore, it is possible to select an optimal data transfer path in an autonomous and distributed manner according to the amount of rain attenuation during the rain.

  In addition, the above-described clear weather and rainy time are described as a rainy weather when the rain attenuation management unit 34 determines that the received signal strength exceeds a predetermined threshold value, and when it is equal to or less than the threshold. Yes. Here, the received signal strength being equal to or less than a predetermined threshold is equivalent to the estimated rain attenuation amount being calculated backward from the received signal strength being equal to or greater than the predetermined threshold.

  In addition, the present invention is characterized in that the uplink and downlink route management is made independent and the transmission route is secured for the uplink that cannot easily increase the transmission power, but the uplink and the downlink are set at different thresholds. It is also possible to manage and finally switch the communication route for the downlink. The same applies to the embodiments described below.

FIG. 2 shows a configuration example of Embodiment 2 of the wireless communication system of the present invention.
The wireless communication system according to the second embodiment uses the IP tunneling technique for the uplink data packet transferred via the second wireless line 42 in the wireless communication system according to the first embodiment, so that the first wireless line 41 It can be handled in exactly the same way as an uplink data packet transferred through the network. The first wireless line 41 and the second wireless line 42 are the same as in the first embodiment.

  The base station (# 1) 10 includes a base station radio function unit (# 1) 11, a switching hub function unit 12, and an IP tunneling termination unit 13 corresponding to the base station function of the first radio channel 41. The base station (# 2) 20 has a base station function of the second radio line 42. Note that the switching hub function unit 12 of the base station (# 1) 10 receives the output destinations of the base station radio function unit (# 1) 11, the IP tunneling termination unit 13, and the network 101 according to the destination of the input data packet. Decide.

  The radio station 30 includes a radio station radio function unit (# 1) 31 corresponding to the radio station function of the first radio channel 41 and a radio station radio function unit (# 2 corresponding to the radio station function of the second radio channel 42). ) 32, a routing unit 33, a rain attenuation management unit 34, and an IP tunneling termination unit 35. The radio station radio function unit (# 1) 31 monitors the received signal strength of the first radio line 41 and notifies the rain attenuation management unit 34 of the information. The rain attenuation management unit 34 compares the received signal strength with a predetermined threshold value, and controls the routing unit 33 according to the result as follows. If the received signal strength exceeds a predetermined threshold, an uplink data packet is output from the routing unit 33 to the radio station radio function unit (# 1) 31. If the received signal strength is less than or equal to a predetermined threshold, an uplink data packet is output from the routing unit 33 to the IP tunneling termination unit 35. The routing unit 33 outputs the downlink data packet input from the radio station radio function unit (# 1) 31 to the user terminal device. The uplink IP packet output from the IP tunneling termination unit 35 is input to the radio station radio function unit (# 2) 32 and transmitted from the radio station radio function unit (# 2) 32 to the second radio line 42. .

  Here, the operation of the wireless communication system according to the second embodiment will be described by dividing it into three patterns of downlink (common during sunny weather and rain), uplink (when sunny), and uplink (when raining).

(1) Downlink (common during fine weather and rain)
A downlink operation of the wireless communication system according to the second embodiment will be described. When a data packet addressed to the user is input from the network 101 to the switching hub function unit 12 of the base station (# 1) 10, the switching hub function unit 12 refers to the switching table and sends the data packet to the base station radio function unit (# 1). ) 11 is output. The base station radio function unit (# 1) 11 converts the data packet into a radio signal and transmits it to the radio station 30 via the first radio line 41. The radio station radio function unit (# 1) 31 of the radio station 30 receives the radio signal transmitted via the first radio line 41 and outputs it to the routing unit 33 as a data packet addressed to the user. The routing unit 33 outputs all data packets input from the radio station radio function unit (# 1) 31 to the user terminal device. The rain attenuation management unit 34 is not involved in the above operation, and the downlink is the same operation during fine weather and during rain.

(2) Uplink (when sunny)
The uplink operation in the clear day of the wireless communication system according to the second embodiment will be described. When a data packet transmitted from the user terminal device toward the network 101 is input to the routing unit 33 of the wireless station 30, the routing unit 33 outputs the packet in a direction in accordance with the instruction from the rain attenuation management unit 34. Here, in the case of fine weather when the received signal strength of the radio station 30 exceeds a predetermined threshold value, the routing unit 33 sends the data packet to the radio station radio function unit (# 1) 31 in accordance with an instruction from the rain attenuation management unit 34. Output to. The radio station radio function unit (# 1) 31 converts the data packet into a radio signal and transmits the radio signal to the base station (# 1) 10 via the first radio line 41. The base station radio function unit (# 1) 11 of the base station (# 1) 10 receives the radio signal transmitted via the first radio line 41, and as a data packet addressed to the network 101, the switching hub function unit 12 Output to. The switching hub function unit 12 outputs all the data packets input from the base station radio function unit (# 1) 11 to the network 101.

(3) Uplink (when raining)
The uplink operation during the rain of the wireless communication system according to the second embodiment will be described. When a data packet transmitted from the user terminal device toward the network 101 is input to the routing unit 33 of the wireless station 30, the routing unit 33 outputs the packet in a direction in accordance with the instruction from the rain attenuation management unit 34. Here, when it is raining when the received signal strength of the radio station 30 is equal to or less than a predetermined threshold, the routing unit 33 outputs the data packet to the IP tunneling termination unit 35 in accordance with an instruction from the rain attenuation management unit 34. At this time, the routing unit 33 uses the destination MAC address of the data packet whose MAC address matches the MAC address of the wireless station radio function unit (# 1) 31 as the MAC address of the IP tunneling termination unit 35. Rewrite to The IP tunneling termination unit 35 extracts the IP packet in the data packet and encapsulates it in another IP packet, and designates the destination of the IP packet as the IP tunneling termination unit 13 of the base station (# 1) 10 to perform the IP tunneling technique. Transfer with. The data packet in which the IP packet is accommodated is input to the radio station radio function unit (# 2) 32, and the radio station radio function unit (# 2) 32 converts the data packet into a radio signal, and the second radio line 42 To the base station (# 2) 20 via.

  The base station (# 2) 20 receives the received radio signal and transmits it to the network 101 as a data packet containing an IP packet addressed to the IP tunneling termination unit 13 of the base station (# 1) 10. The network 101 transfers the data packet addressed to the IP tunneling termination unit 13 of the base station (# 1) 10 to the base station (# 1) 10 by a normal routing process. The switching hub function unit 12 of the base station (# 1) 10 outputs the data packet to the IP tunneling termination unit 13 that is the destination. The IP tunneling termination unit 13 extracts an IP packet addressed to the network 101 from the encapsulated IP packet and outputs it as a data packet to the switching hub function unit 12. The switching hub function unit 12 outputs all data packets input from the IP tunneling termination unit 13 to the network 101.

  With the above control function, between the radio access system using the first radio channel 41 and the radio access system using the second radio channel 42, all control signals and complicated protocol processing are performed in the uplink. Therefore, it is possible to select an optimal data transfer path in an autonomous and distributed manner according to the amount of rain attenuation during the rain.

  Even in the case of handover of the conventional mobile radio access system described with reference to FIG. 6, since the location of the mobile terminal station is uncertain, IP packet transfer processing is performed using an IP tunneling technique such as mobile IP. ing. However, the IP tunneling of the present invention is the case where the starting point and the end point of the tunneling are always the same, and complicated processing such as conventional mobility management is not necessary, and can be handled with fixed and simple processing. However, although it is necessary to always set the connection between the first wireless line 41 and the second wireless line 42 at the same time, the second wireless line 42 uses only the uplink in the above embodiment, and is equivalent. Since it is used only when a large amount of rain attenuation occurs due to a heavy rainfall, the load on the radio access system using the second radio line 42 is extremely limited.

  In the above description, the base station radio function unit (# 1) 11, the radio station radio function unit (# 1) 31, the IP tunneling termination units 13 and 35, the switching hub function unit 12 and the routing unit 33 are input. It is not necessary to perform the above signal processing on all data packets. For example, the base station radio function unit (# 1) 11 determines the transfer destination of the input data packet with reference to the MAC address or IP address of the packet, but discards the packet whose destination is unknown. Since the other parts do not transfer useless packets, packets having addresses with unknown destinations are discarded. However, broadcast packets, multicarrier packets, etc. are basically subject to transfer as before. The same applies to the first embodiment and the following embodiments.

FIG. 3 shows a configuration example of a third embodiment of the wireless communication system of the present invention.
The radio station 30 according to the second embodiment is provided with the radio functions of both the first radio channel 41 and the second radio channel 42 as a user-side terminal station. The wireless communication system according to the third embodiment is characterized in that the wireless station 30 according to the second embodiment is used as the relay station 50, the wireless station wireless function unit (# 3) 36 is connected to the routing unit 33, and the wireless station wireless function The unit (# 3) 36 and the terminal station (# 3) 103 on the user side are connected via the third wireless line 43. As a result, the terminal station 103 on the user side need only have the wireless function of the third wireless line 43, and has the same configuration as the conventional terminal station shown in FIG.

  In addition, each connection process of the relay station 50 of the third embodiment, the base station (# 1) 10, the base station (# 2) 20, and the network 101 in place of the wireless station 30 of the second embodiment is described in the embodiment. Since this is exactly the same as 2, the description is omitted. The configuration of the wireless communication system according to the third embodiment can be similarly applied to the configuration of the wireless communication system according to the first embodiment.

  Here, the first wireless line 41 is assumed to be, for example, an FWA system using a quasi-millimeter wave band. The second wireless line 42 is assumed to be a wireless system that complies with the WiMAX standard using, for example, a microwave band. As the third wireless line 43, for example, an IEEE802.11 wireless LAN system using a microwave band is assumed. Since the signal of the third wireless line 43 is relayed via the first wireless line 41 and the second wireless line 42, the signals from the first wireless line 41 and the second wireless line 42 are used. There is no problem even in a system with a narrow service area (200 to 300 m for an IEEE802.11 wireless LAN system). Further, as the third wireless line 43, for example, an FWA system using a millimeter wave band such as a 60 GHz band may be used. In any case, the frequency band used for the third radio line 43 can be freely set regardless of the frequency band used for the first radio line 41 and the second radio line 42.

FIG. 4 shows a configuration example of a fourth embodiment of the wireless communication system of the present invention.
In the figure, the wireless communication system according to the fourth embodiment includes base stations (# 1) 10a and 10b, a base station (# 2) 20, a base station (# 1) 10a and a first wireless line 41 connected to a network 101. The relay stations 50a and 50b connected via the base station (# 1) 10b and the relay station 50c connected via the first radio channel 41, the base station (# 2) 20 and the second radio channel 42 The relay stations 50a to 50c are connected to each other via terminal stations (# 3) 103a to 103g connected to the relay stations 50a to 50c and the third radio line 43, respectively. The configurations of the base stations (# 1) 10a and 10b, the base station (# 2) 20, and the relay stations 50a to 50c are the same as those in the third embodiment.

  In the fourth embodiment, the base station (# 1) 10a and the base station (# 1) 10b each cover an area covered by the first wireless line 41, and the base station (# 2) 20 covers the second wireless line 42. The areas and the areas covered by the relay stations 50a to 50c with the third wireless line 43 do not need to be the same, and the station placement design can be performed independently. For example, in the case where a microwave-band WiMAX system is used as the second wireless line 42, a wide area can be covered at one time, so that a large number of base stations for the first wireless line 41 are included in this area. (# 1) There is no problem even if 10a and 10b are included.

  Further, in FIG. 4, the base stations (# 1) 10a and 10b, the base station (# 2) 20, and the terminal stations 103a to 103g are each provided with one antenna, and the relay stations 50a to 50c are provided with three antennas. However, there is no restriction on the number of each antenna. For example, a configuration in which a plurality of antennas are used for each of the first wireless line 41, the second wireless line 42, and the third wireless line 43 may be used. Also, when using a similar frequency band, or when using the same standard radio channel simultaneously on any of the first radio channel 41, the second radio channel 42, and the third radio channel 43, relay The antennas of the stations 50a to 50c can be shared.

  Further, the terminal stations 103a to 103g may be installed either outdoors or indoors as shown in FIG. 5, or may be connected to a user terminal device such as a personal computer via a router or directly, Further, it may be a user terminal device directly operated by the user, such as a personal computer with wireless function or a game machine. Further, it may be a terminal station having a router function.

10 Base station (# 1)
11 Base station radio function section (# 1)
12 Switch Hub Function Unit 13 IP Tunneling Termination Unit 20 Base Station (# 2)
30 wireless station 31 wireless station wireless function unit (# 1)
32 Radio station radio function part (# 2)
33 Routing unit 34 Rain attenuation management unit 35 IP tunneling termination unit 36 Radio station radio function unit (# 3)
41 First wireless line 42 Second wireless line 43 Third wireless line 50 Relay station 101 Network 103 Terminal station (# 3)

Takeshi Hattori, Masanobu Fujioka, Revised Wireless Broadband Textbook -High Speed IP Wireless-, Impress R & D, pp.58-66

Claims (9)

A first base station connected to a network is connected to a user-side radio station via a first radio line using a first frequency band, and downlink communication from the network to the radio station and a radio station to the network In a wireless communication system for performing uplink communication to a mobile station via a first wireless line and a first base station,
A second base station connected to the network and connected to the wireless station via a second wireless line using a second frequency band that uses a second frequency band having a lower rain attenuation than the first frequency band;
The radio station is
Means for connecting to the second base station via the second radio link;
Means for monitoring received signal strength of the downlink received via the first radio link;
When the received signal strength exceeds a predetermined threshold, the downlink and the uplink communication are performed via the first wireless line, and when the received signal strength is equal to or lower than the predetermined threshold, the downlink And a means for performing the uplink communication via the first wireless line and performing the uplink communication via the second wireless line. A first base station connected to the network is connected to a wireless station via a first wireless line using the first frequency band, and the wireless station is connected via a third wireless line using the third frequency band. In a wireless communication system that is connected to a terminal station on a user side and performs downlink communication from a network to a wireless station and uplink communication from a wireless station to a network via a first wireless line and a first base station ,
A second base station connected to the network and connected to the wireless station via a second wireless line using a second frequency band that uses a second frequency band having a lower rain attenuation than the first frequency band;
The radio station is
Means for connecting to the second base station via the second radio link;
Means for monitoring received signal strength of the downlink received via the first radio link;
When the received signal strength exceeds a predetermined threshold, the downlink and the uplink communication are performed via the first wireless line, and when the received signal strength is equal to or lower than the predetermined threshold, the downlink And a means for performing the uplink communication via the first wireless line and performing the uplink communication via the second wireless line. The wireless communication system according to claim 1 or 2,
When the received signal strength is equal to or lower than a predetermined threshold, the radio station is configured to send an IP packet accommodated in a data packet to be transferred by the uplink communication to the first base station as another destination A means for encapsulating the packet in an IP packet and transferring the packet via the second wireless line;
The first base station terminates the another IP packet transferred via the second radio line, the second base station, and the network, and extracts the encapsulated IP packet. A wireless communication system comprising means for sending a data packet to the network. The wireless communication system according to claim 1 or 2,
The wireless communication system, wherein the first frequency band is a quasi-millimeter wave band or a millimeter wave band. The wireless communication system according to claim 4, wherein
The wireless communication system, wherein the second frequency band is one of a microwave band, a UHF band, and a VHF band. The wireless communication system according to claim 2,
The wireless communication system, wherein the second wireless line is a wireless line compliant with WiMAX standard, and the third wireless line is a wireless line compliant with IEEE802.11 wireless LAN standard. A first base station connected to a network is connected to a user-side radio station via a first radio line using a first frequency band, and downlink communication from the network to the radio station and a radio station to the network In a wireless communication method for performing uplink communication with a first wireless line and a first base station,
A second base station connected to the network and connected to the wireless station via a second wireless line using a second frequency band that uses a second frequency band having a lower rain attenuation than the first frequency band;
The radio station comprises means for connecting to the second base station via the second radio line, monitors the received signal strength of the downlink received via the first radio line, and When the received signal strength exceeds a predetermined threshold, communication of the downlink and the uplink is performed via the first wireless line, and when the received signal strength is equal to or lower than the predetermined threshold, A wireless communication method, wherein communication is performed via the first wireless line, and uplink communication is performed via the second wireless line. A first base station connected to the network is connected to a wireless station via a first wireless line using the first frequency band, and the wireless station is connected via a third wireless line using the third frequency band. In a wireless communication method connected to a user-side terminal station and performing downlink communication from a network to a wireless station and uplink communication from a wireless station to a network via a first wireless line and a first base station ,
A second base station connected to the network and connected to the wireless station via a second wireless line using a second frequency band that uses a second frequency band having a lower rain attenuation than the first frequency band;
The radio station comprises means for connecting to the second base station via the second radio line, monitors the received signal strength of the downlink received via the first radio line, and When the received signal strength exceeds a predetermined threshold, communication of the downlink and the uplink is performed via the first wireless line, and when the received signal strength is equal to or lower than the predetermined threshold, A wireless communication method, wherein communication is performed via the first wireless line, and uplink communication is performed via the second wireless line. In the wireless communication method according to claim 7 or 8,
When the received signal strength is equal to or lower than a predetermined threshold, the radio station is configured to send an IP packet accommodated in a data packet to be transferred by the uplink communication to the first base station as another destination Encapsulated in an IP packet, forwarded via the second radio link,
The first base station terminates the another IP packet transferred via the second radio line, the second base station, and the network, and extracts the encapsulated IP packet. A wireless communication method characterized by transmitting a data packet to the network.

Images