JP2014183538A - Radio network system and radio apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a high transmission rate even when rainfall strength is high.SOLUTION: A radio network system comprises a plurality of nodes for performing radio communication using a frequency band where communication quality is deteriorated by rainfall, and reconstructs network topology according to deterioration prediction of the communication quality. The radio network system comprises: a master node 3 which predicts whether or not communication quality in any radio link is deteriorated by occurrence of a factor affecting communication quality of each radio link, and gives an instruction to add a radio link not passing through a radio link whose communication quality's deterioration is predicted and delete the radio link whose communication quality's deterioration is predicted when a result of the prediction shows that communication quality of any radio link is deteriorated; and a plurality of slave nodes 5 for performing addition or deletion of the radio links according to the instruction of the master node.

Description

  The present invention includes a wireless network system that includes a plurality of nodes that perform wireless communication using a frequency band in which communication quality deteriorates due to rain, and that reconfigures the network topology in accordance with a predicted deterioration in communication quality, and a parent of the wireless network system. The present invention relates to a radio that functions as a node.

  In recent years, with the spread of smartphones and tablet terminals, mobile data traffic has increased explosively. Along with this, cellular networks for accommodating mobile data traffic have also evolved, LTE (Long Term Evolution) has been deployed as a wireless system capable of providing large-capacity communication, and in order to accommodate the generated traffic, Many radio base stations are deployed.

  In order to establish a base station, not only a wireless device but also a backhaul line connecting the base station and the network side is required. The backhaul line is usually configured by a wire such as an optical fiber that can provide stable communication with a large capacity. On the other hand, new construction of optical fiber requires high cost and construction days, so there is a need for a low-cost and easy-to-install wireless line, and high frequency of several tens of gigahertz is used in combination with the optical line. FWA (Fixed Wireless Access) systems using bands have come to be used.

  This frequency band is called a “millimeter wave band”. When a radio link is constructed in this millimeter wave band, the transmission signal is attenuated by the influence of rain (hereinafter referred to as “rain attenuation”). For this reason, it is difficult to ensure a stable transmission speed. In particular, in the case of a temporarily high rainfall such as heavy rain, there is a problem that a link down occurs and an operation rate is reduced. For example, in Patent Document 1, a rain attenuation amount is calculated, and adaptive modulation is performed in consideration of the calculated rain attenuation amount. By adopting an optimum modulation method according to the propagation path situation, it is intended to ensure sufficient line quality even during rain and to extend the line distance.

JP 2007-221357 A

  However, if the wireless apparatus is provided with an adaptive modulation function as in the technique described in Patent Document 1, the capital for the equipment is increased. Also, in the case of rain with high rainfall intensity, such as so-called “guerrilla heavy rain”, the rain attenuation amount increases, so a modulation method with a low multi-value number such as QPSK is selected. The rate becomes low and it becomes difficult to improve the operating rate.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a wireless network system and a wireless device capable of maintaining a high transmission rate even when the rainfall intensity is high. .

  (1) In order to achieve the above object, the present invention takes the following measures. That is, the wireless network system of the present invention is a wireless network system that includes a plurality of nodes that perform wireless communication using a frequency band in which communication quality deteriorates due to rain, and reconfigures the network topology according to the prediction of communication quality deterioration. Therefore, it is predicted whether the communication quality of any radio link will deteriorate due to the occurrence of a factor that affects the communication quality of each radio link. As a result of the prediction, the communication quality of any radio link deteriorates. Then, if predicted, a radio link that does not pass through a radio link that is predicted to deteriorate the communication quality is added, and a parent node that instructs to delete the radio link that is predicted to deteriorate the communication quality; and A plurality of child nodes that add or delete radio links in accordance with instructions from the parent node. And butterflies.

  As described above, the parent node predicts whether or not the communication quality of any radio link deteriorates due to the occurrence of a factor that affects the communication quality of each radio link. When it is predicted that the communication quality will deteriorate, a radio link that does not pass through the radio link that is predicted to deteriorate the communication quality is added, and an instruction to delete the radio link that is predicted to deteriorate the communication quality is issued. Since a node adds or deletes a radio link according to the instruction of the parent node, if communication quality is expected to deteriorate in any of the radio links, a new radio link is set up avoiding that radio link. In addition, it is possible to avoid a decrease in the network operation rate and maintain a high transmission rate.

  (2) Also, in the wireless network system of the present invention, the factor affecting the communication quality is rain attenuation, and the parent node obtains rainfall information and predicts the rain attenuation amount of each radio link, A radio link is added or deleted in accordance with a prediction result of rainfall attenuation.

  In this way, the factor that affects the communication quality is rain attenuation, and the parent node obtains the rainfall information, predicts the rain attenuation amount of each radio link, and according to the prediction result of the rain attenuation amount, Since addition or deletion is performed, if any of the radio links is expected to deteriorate in communication quality due to rainfall, a new radio link can be established by avoiding the radio link, and the network operation rate A decrease can be avoided.

  (3) Further, in the wireless network system of the present invention, each of the child nodes detects the communication quality of the radio link, the traffic amount or the interference amount from another radio link, and detects the communication quality of the detected radio link and the traffic. The amount of interference or the amount of interference from other radio links to the parent node, and the parent node is based on the communication quality of the radio link, the traffic amount or the amount of interference from other radio links notified from each of the child nodes. If the communication quality of the radio link of each child node deteriorates, and the prediction results that the communication quality of the radio link of each child node will deteriorate, the communication quality deteriorates. Then, a radio link that does not pass through the predicted radio link is added, and an instruction to delete the radio link that is predicted to deteriorate the communication quality is issued. And wherein the door.

  In this way, each child node detects the communication quality of the radio link, the amount of traffic or the amount of interference from other radio links, and detects the communication quality of the detected radio link, the amount of traffic or the amount of interference from other radio links. To the parent node, and the parent node determines the communication quality of the radio link of each child node based on the communication quality of the radio link notified from each child node, the amount of traffic or the amount of interference from other radio links. If it is predicted that the communication quality of the radio link of each child node will deteriorate as a result of the prediction, add a radio link that does not pass through the radio link predicted to deteriorate the communication quality, Since an instruction to delete a radio link predicted to deteriorate the communication quality is given, it becomes possible to autonomously reconfigure the network topology.

  (4) In the wireless network system of the present invention, the parent node adds or deletes a radio link so that a transmission path including the added radio link maintains a desired transmission rate. To do.

  In this way, the parent node adds or deletes the radio link so that the transmission path including the added radio link maintains the desired transmission rate. Therefore, the parent node not only avoids the radio link having deteriorated communication quality. It is possible to configure a network topology that satisfies an allowable delay amount. For example, if you configure a network topology that reduces the distance between nodes to avoid rain attenuation, the number of hops from the child node to the parent node will increase, but even if it increases, it will result from an increase in the number of hops It is possible to add or delete a radio link so that the delay amount is within an allowable range.

  (5) In the wireless network system of the present invention, the parent node adds or deletes a wireless link so that the number of hops in the transmission path is minimized.

  In this way, the parent node adds or deletes the radio link so that the number of hops in the transmission path is minimized, so that the delay amount can be minimized and the transmission rate can be kept high. For example, when rain attenuation occurs and the network topology is reconfigured, the network topology may have a large number of hops and a small inter-node distance. After that, when the effect of rain attenuation becomes smaller, the delay amount becomes relatively large if the network topology considering rain attenuation is taken into account, so it is possible to reduce the delay amount by returning to the original network topology. It becomes.

  (6) Further, the wireless device of the present invention includes a plurality of nodes that perform wireless communication using a frequency band in which communication quality deteriorates due to rain, and reconfigures the network topology according to the prediction of communication quality deterioration. A radio unit that functions as a parent node of the system, the prediction unit predicting whether or not the communication quality of any one of the radio links deteriorates due to the occurrence of a factor that affects the communication quality of each radio link; As a result, when it is predicted that the communication quality of any one of the radio links is deteriorated, a radio link that does not pass through the radio link that is predicted to deteriorate the communication quality is added and the communication quality is predicted to deteriorate. And a topology management unit that instructs a child node to delete a radio link.

  In this way, it is predicted whether the communication quality of any radio link will deteriorate due to the occurrence of factors affecting the communication quality of each radio link. As a result of the prediction, the communication quality of any radio link will deteriorate. Then, if predicted, since a radio link that does not pass through the radio link that is predicted to deteriorate the communication quality is added, and an instruction to delete the radio link that is predicted to deteriorate the communication quality is given to the child node, If communication quality is expected to deteriorate in any of the wireless links, avoid the wireless link and set a new wireless link to avoid a decrease in the network operation rate and maintain a high transmission rate. It becomes possible.

  (7) In the wireless device of the present invention, the factor that affects the communication quality is rain attenuation, and the prediction unit acquires rainfall information, predicts the rain attenuation amount of each radio link, and The topology management unit adds or deletes a radio link according to the prediction result of the rain attenuation amount.

  In this way, the factor that affects the communication quality is rain attenuation, the prediction unit obtains rainfall information, predicts the rain attenuation amount of each wireless link, and the topology management unit predicts the rain attenuation amount. Therefore, if any wireless link is expected to deteriorate in communication quality due to rainfall, a new wireless link can be established by avoiding the wireless link. It is possible to avoid a decrease in the network operation rate.

  (8) Further, in the wireless device of the present invention, the prediction unit is based on communication quality of a wireless link, traffic amount, or interference amount from other wireless links notified from each child node constituting the wireless network system. The topology management unit predicts whether or not the communication quality of the radio link of each child node is deteriorated as a result of the prediction. A radio link that does not pass through a radio link that is predicted to deteriorate the communication quality is added, and an instruction to delete the radio link that is predicted to deteriorate the communication quality is issued.

  As described above, the prediction unit performs communication on the radio link of each child node based on the communication quality of the radio link, the traffic amount, or the interference amount from other radio links notified from each child node constituting the radio network system. The topology management unit predicts whether or not the quality is deteriorated, and if it is predicted that the communication quality of the radio link of each child node is deteriorated as a result of the prediction, the topology management unit does not pass through the radio link that is predicted to deteriorate the communication quality. Since a radio link is added and an instruction to delete a radio link predicted to deteriorate communication quality is given, it becomes possible to autonomously reconfigure the network topology.

  (9) Further, in the radio of the present invention, the topology management unit adds or deletes a radio link so that a transmission path including the added radio link maintains a desired transmission rate. To do.

  As described above, the topology management unit adds or deletes the radio link so that the transmission path including the added radio link maintains the desired transmission rate. Therefore, the topology management unit only avoids the radio link having deteriorated communication quality. It is possible to construct a network topology that satisfies the allowable delay amount. For example, if you configure a network topology that reduces the distance between nodes to avoid rain attenuation, the number of hops from the child node to the parent node will increase, but even if it increases, it will result from an increase in the number of hops It is possible to add or delete a radio link so that the delay amount is within an allowable range.

  (10) In the wireless device of the present invention, the topology management unit adds or deletes a wireless link so that the number of hops in the transmission path is minimized.

  In this way, the topology management unit adds or deletes wireless links so that the number of hops in the transmission path is minimized, so that the delay amount can be minimized and the transmission rate can be kept high. For example, when rain attenuation occurs and the network topology is reconfigured, the network topology may have a large number of hops and a small inter-node distance. After that, when the effect of rain attenuation becomes smaller, the delay amount becomes relatively large if the network topology considering rain attenuation is taken into account, so it is possible to reduce the delay amount by returning to the original network topology. It becomes.

  According to the present invention, when any one of the radio links is expected to deteriorate in communication quality, a new radio link can be set by avoiding the radio link, and a decrease in the network operation rate is avoided. It becomes possible to do.

It is a block diagram which shows schematic structure of the parent node which comprises the radio | wireless network system which concerns on embodiment of this invention, and a child node. It is a figure which shows the example of a wireless network structure in this embodiment. It is a figure which shows the example of a wireless network structure in this embodiment. It is a figure which shows the example of a wireless network structure in this embodiment.

  The present inventors pay attention to the fact that the transmission signal is attenuated due to the influence of rain on a millimeter-wave band radio link, so that the rainfall can be predicted to ensure a rain margin according to the rain attenuation. By adding a wireless link with a short inter-node distance and reconfiguring the topology to build a new path from the ingress node containing the wireless link to the egress node. However, the present inventors have found that it is possible to secure a high transmission rate and to improve the operating rate of the wireless network, and have made the present invention.

  That is, the present invention is a wireless network system including a plurality of nodes that perform wireless communication using a frequency band in which communication quality deteriorates due to rain, and reconfigures the network topology in accordance with the prediction of communication quality deterioration. Predicting whether the communication quality of any radio link will deteriorate due to the occurrence of factors affecting the communication quality of the radio link, and as a result of the prediction, it was predicted that the communication quality of any radio link will deteriorate In this case, a radio link that does not pass through a radio link that is predicted to deteriorate the communication quality is added, and a parent node that gives an instruction to delete the radio link that is predicted to deteriorate the communication quality, and an instruction from the parent node And a plurality of child nodes that add or delete a radio link.

  As a result, when any of the radio links is expected to deteriorate in communication quality, the present inventors avoid the radio link, set a new radio link, and avoid a decrease in the network operation rate. In addition, a high transmission rate can be maintained.

  The wireless network system according to the present embodiment is configured by organically connecting a plurality of nodes (wireless devices) by wireless links. Each node has a function of adding a new link or deleting an established link. In such a wireless network system, when it is assumed that the signal quality of the radio link deteriorates due to rain attenuation, or when the signal quality of the radio link deteriorates, neighboring nodes cooperate to reduce the signal quality deterioration. Or a new radio link is added that does not deteriorate.

  This can be realized by adding the radio link so that the radio link is shortened according to the rain attenuation amount because the rain attenuation amount of the radio link increases in proportion to the length of the radio link. When a wireless link that is shorter than the wireless link is configured for a wireless link that configures an end node from a certain start point node, the number of nodes that pass from the start point node to the end point node increases. For this reason, the amount of delay increases due to the processing load at the passing node. For this reason, when a new route is configured by adding a new wireless link, the delay amount and the necessary transmission rate according to the application are considered.

  Furthermore, if the rain attenuation is expected to be small, or if it is small, the network topology can be changed by adding / deleting radio links according to the delay amount and required transmission rate according to the application. Reconfigure. As a result, even when the rainfall intensity is high, it is possible to maintain a high transmission rate or a low delay according to the application used on the wireless network. Hereinafter, embodiments of the present invention will be specifically described.

  FIG. 1 is a block diagram showing a schematic configuration of a parent node and a child node constituting a wireless network system according to an embodiment of the present invention. 2A to 2C are diagrams illustrating a configuration example of a wireless network in the present embodiment. The wireless network system according to this embodiment includes a parent node 3 and a child node 5. In FIG. 1, one child node 5 is drawn, but this is for convenience of explanation, and actually, a plurality of child nodes are provided.

  The parent node 3 acquires information regarding factors that affect the communication quality of the radio link from the external database 1. The external database 1 may be configured so as to predict the amount of rainfall and the amount of rain attenuation by taking in external information such as a weather forecast in advance, or by taking in information from other wired and wireless networks and predicting it. Also good. Further, it may be based on information such as rain attenuation from the own node or other nodes in the same wireless network. In addition, the parent node 3 obtains “information regarding communication quality of the radio link”. For example, the communication quality of the radio link measured by the child node 5, the amount of traffic, or the amount of interference from other radio links.

  The rainfall attenuation amount prediction unit 7 predicts the rain attenuation amount in each radio link based on the acquired information. The topology management unit 9 obtains the prediction information indicating the rainfall attenuation amount from the rain attenuation amount prediction unit 7, and uses the existing radio link to instruct the child node that changes the network topology based on the prediction information. To do. This instruction includes information indicating which radio link is added in the target child node, information indicating the addition timing, and information indicating the radio frequency of the link to be added. Here, in the topology, not only when the parent node and the child node are 1 to n as shown in FIG. 2A, but also when the child node is connected in a column as shown in FIGS. 2B and 2C. is there. 2B and 2C, when a child node that has received an instruction from the parent node is not an instruction to add / delete a radio link to its own node, The instruction is transmitted (through) as it is to the subordinate child nodes.

  The rain attenuation amount prediction unit 7 deteriorates the communication quality of the radio link of the child node 5 based on the communication quality of the radio link notified from the child node 5, the traffic volume, or the interference amount from other radio links. It may be predicted whether or not. Then, when it is predicted that the communication quality of the radio link of the child node 5 is deteriorated as a result of the prediction, the topology management unit 9 adds a radio link that does not pass through the radio link that is predicted to deteriorate the communication quality. In addition, an instruction to delete the radio link predicted to deteriorate the communication quality may be given.

  Further, the topology management unit 9 acquires the radio link quality information acquired from the radio link state management unit 13-1, selects a radio link to be added or deleted, and displays the selection result as the radio link addition / removal of the child node 5. The data is output to the deletion unit 11-2. The radio link state management unit 13-1 acquires the radio link quality information from the child node 5 and outputs it to the topology management unit 9.

  In the child node 5, the radio link addition / deletion unit 11-2 executes addition or deletion of the radio link designated by the parent node 3. The wireless link state management unit 13-2 manages the state of the wireless link used by the own device and periodically notifies the parent node 3 of the state.

  That is, each child node 5 adds a radio link based on the information notified from the parent node 3, and when the addition is completed, notifies the end node using the existing radio link. To do. When the parent node 3 receives the notification of completion of addition of all the radio links, the parent node 3 instructs the corresponding child node to delete the unnecessary radio link by adding a new radio link among the existing radio links. . The child node 5 that has received the wireless link deletion notification, after deleting the wireless link, notifies the parent node 3 of the completion of the wireless link deletion through a new route including the newly established wireless link.

  Next, FIGS. 2A to 2C show a state in which a plurality of child nodes (1 to 5) are connected to one parent node (0). The child nodes (1 to 5) are installed, for example, in a local site where the radio base station is arranged, and the radio link between the child node (1 to 5) and the parent node (0) is connected to the radio base station. A backhaul line for connecting nodes on the network side.

  When the communication quality of the wireless link is good, such as when the weather is clear, a network topology in which the inter-node distance is increased so as to minimize the delay amount is configured as shown in FIG. 2A. That is, FIG. 2A shows a normal state. On the other hand, as shown in FIG. 2B and FIG. 2C, when the rain attenuation amount is increased due to thunderstorms or the like in any of the wireless links, the data is transferred to the parent node while bypassing the wireless link. Therefore, a new network topology is reconfigured by selecting a radio link having a small inter-node distance. For example, it is assumed that the normal state of FIG. 2A changes to the state of FIG. 2B. In this case, the radio link between the parent node (0) and the child node (3) and the radio link between the parent node (0) and the child node (4) are deleted, and the child node (2) and the child node are deleted. A radio link between the node (3) and a radio link between the child node (3) and the child node (4) are added. FIG. 2B shows the network topology after addition of a new radio link is completed and deletion of unnecessary radio links is completed.

  Further, for example, assume that the state in FIG. 2A at the normal time changes to the state in FIG. 2C. In this case, the network topology is reconfigured when the amount of rain attenuation increases in the radio link between the parent node (0) and the child node (2) due to the influence of thunderstorms or the like. That is, the radio link between the parent node (0) and the child node (1), the radio link between the parent node (0) and the child node (2), the parent node (0) and the child node (3) And the wireless link between the parent node (0) and the child node (4), and the wireless link between the child node (1) and the child node (2), the child node ( 2) a radio link between the child node (3), a radio link between the child node (2) and the child node (4), and a radio between the child node (4) and the child node (5) Add a link. FIG. 2C shows the network topology after the addition of a new radio link is completed and the deletion of unnecessary radio links is completed. As described above, the network topology configuration shown in FIGS. 2B and 2C may be obtained depending on the amount of rainfall and the area of rainfall.

  On the other hand, the parent node (0) changes in accordance with the prediction result of the rain attenuation when the rain attenuation falls below a predetermined threshold value for a certain period in the radio link established for the radio quality degradation due to rain attenuation. Revert to the previous network topology configuration. This is to minimize the amount of delay. The parent node (0) notifies the child nodes (1 to 5) of an instruction for adding a radio link and necessary information. This instruction includes information indicating which radio link is added in the target child node, information indicating the addition timing, and information indicating the radio frequency of the link to be added. Each child node (1 to 5) adds a radio link based on the notified information. When the addition is completed, the child node (1-5) notifies the end node using the existing radio link. As described above, when the weather is fine, a wireless network with a minimum delay can be established by returning the network topology to FIG. 2A.

  As described above, according to the present embodiment, a radio link with a short inter-node distance is added so that a rain margin according to the rain attenuation amount can be ensured, and from the ingress node including the radio link to the egress node. By reconfiguring the topology so as to construct a new path, it is possible to ensure a high transmission rate even during rain and improve the operating rate. In addition, in fine weather, by adding a wireless link so that the distance between links becomes long, the network topology configuration can be reconstructed and a link with a small amount of delay can be configured.

DESCRIPTION OF SYMBOLS 1 External database 3 Parent node 5 Child node 7 Rain attenuation prediction part 9 Topology management part 11-2 Radio link addition / deletion part 13-1 Radio link state management part 13-2 Radio link state management part

Claims (10)

A wireless network system including a plurality of nodes that perform wireless communication using a frequency band in which communication quality deteriorates due to rain, and reconfigures a network topology according to a prediction of communication quality deterioration,
It is predicted whether the communication quality of any radio link will deteriorate due to the occurrence of a factor that affects the communication quality of each radio link. As a result of the prediction, it is predicted that the communication quality of any radio link will deteriorate. A radio link that does not pass through the radio link that is predicted to deteriorate the communication quality, and a parent node that instructs to delete the radio link that is predicted to deteriorate the communication quality;
A radio network system comprising: a plurality of child nodes that add or delete radio links in accordance with instructions from the parent node.   The factor affecting the communication quality is rain attenuation, and the parent node obtains rainfall information, predicts the rain attenuation amount of each radio link, and adds or adds a radio link according to the prediction result of the rain attenuation amount. 2. The wireless network system according to claim 1, wherein deletion is performed. Each of the child nodes detects the communication quality of the radio link, the traffic amount or the interference amount from other radio links, and the detected communication quality of the radio link, the traffic amount or the interference amount from other radio links is detected by the parent node. Notify the node,
The parent node determines whether or not the communication quality of the radio link of each child node is deteriorated based on the communication quality, traffic volume, or interference amount from other radio links notified from each child node. Predicting and, as a result of the prediction, if it is predicted that the communication quality of the radio link of each child node is degraded, a radio link that does not pass through the radio link that is predicted to degrade the communication quality is added, and the communication The radio network system according to claim 1, wherein an instruction to delete a radio link predicted to deteriorate in quality is issued.   4. The parent node adds or deletes a radio link so that a transmission path including the added radio link maintains a desired transmission rate. Wireless network system.   The radio network system according to any one of claims 1 to 3, wherein the parent node adds or deletes a radio link so that the number of hops of a transmission path is minimized. A wireless device comprising a plurality of nodes that perform wireless communication using a frequency band in which communication quality deteriorates due to rain, and functions as a parent node of a wireless network system that reconfigures a network topology in accordance with a prediction of communication quality deterioration. ,
A prediction unit that predicts whether or not the communication quality of any radio link deteriorates due to the occurrence of a factor that affects the communication quality of each radio link, and the communication quality of any radio link deteriorates as a result of the prediction Then, when predicted, a radio link that does not pass through the radio link that is predicted to deteriorate the communication quality is added, and an instruction to delete the radio link that is predicted to deteriorate the communication quality is issued to the child node. And a topology management unit. The factor affecting the communication quality is rain attenuation,
The prediction unit obtains rainfall information, predicts the rain attenuation amount of each radio link,
The radio apparatus according to claim 6, wherein the topology management unit adds or deletes a radio link according to the prediction result of the rainfall attenuation amount. The prediction unit is configured to determine the communication quality of the radio link of each child node based on the communication quality of the radio link notified from each child node constituting the radio network system, the amount of traffic, or the amount of interference from other radio links. Predict whether or not
If it is predicted that the communication quality of the radio link of each child node is degraded as a result of the prediction, the topology management unit adds a radio link that does not pass through the radio link that is predicted to deteriorate the communication quality. The radio device according to claim 6, wherein an instruction to delete the radio link predicted to deteriorate the communication quality is issued.   9. The topology management unit adds or deletes a radio link so that a transmission path including the added radio link maintains a desired transmission rate. The listed radio. The wireless device according to any one of claims 6 to 8, wherein the topology management unit adds or deletes a wireless link so that the number of hops of a transmission path is minimized.

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