ES2222082B1 - PROTOCOL FOR THE CONSTRUCTION OF EXTENSIVE AREA DATA COMMUNICATION NETWORKS BASED ON SHORT-RANGE RADIO TECHNOLOGY. - Google Patents

Abstract

Protocol for the construction of wide area data communication networks based on short range radio technology. A protocol is developed for the construction of data communication networks that can be applied in a large geographical area, with the use of short-range radio technology (typically tens of meters), for data communication between a large number (hundreds or thousands) of autonomous, fixed or mobile elements, without any external energy input, and capable of being kept in operational state for long periods of time (of the order of some years). The invention provides for the formation of a network topology consisting of a multiplicity of nodes, capable of establishing links between each node and its neighbors, depending on the energy expenditure of each link. The topology provides for the establishment of special nodes for liaison with other external networks, through which the provision of information is made to the Management Centers where it is stored and processed.

Description

Protocol for the construction of networks of Wide area data communication based on radio technology short range

Object of the invention

The present invention relates to a protocol for the construction of area data communication networks Extensive based on short-range radio technology, which provides essential novelty features and remarkable advantages with regarding the systems and means known and used for same purposes in the current state of the art.

More particularly, the invention proposes the development of a data communication system for applications which requires continuous information from a large number of autonomous elements (thousands or hundreds of thousands), fixed or mobile, distributed over a large geographical area (one area metropolitan) using short-range radio technologies (typically up to a hundred meters). The invention lies in the design of applications that are capable of interconnecting nodes from the network that may be far from each other several kilometers through the interconnection of other intermediate network nodes. These applications, which run distributed on each element of the network, are able to optimize the global energy expenditure of system to get these network functionality autonomous elements (normally without external energy input) over a lifetime of several years. Being the applications designed towards optimization of energy expenditure and global use of system energy, when there are elements in the network with external energy supply (power supply of the mains), this extra energy is redistributed to the other elements of the network allowing overall system performance to be seen increased

The scope of the invention is It is obviously comprised within the sector of telecommunications, and especially communications from data.

Background of the invention

In the field of research, theoretical studies on the formation of ad-hoc network of nodes, based on short-jump radio technologies such as IEEE 802.15.1 (Bluetooth) or IEEE 802.15.4 (Zigbee) standards, are known. Typically these studies do not provide solutions to the needs towards which the invention has been raised: a large number of nodes distributed over a large area that operate without external energy supply for a large number of years. These studies are limited to the application of the standard offered by the technology to obtain networks of nodes located in the same coverage area.

Networks that use devices are known hubs to collect node information terminals that you can have associated. In these solutions, the number of nodes associated with the hub can be from one to  thousands and, communication is established when the hub interrogate the node from which you want to obtain the stored information. They are also characterized because they usually have external power supply from the low voltage power network, so that when it is not, the performance is very low, requiring a high maintenance The hub can be fixed or mobile. When the hub is fixed, it can act as a link to more extensive telecommunications networks that redirect data obtained towards Data Centers where the information. When it is mobile, the technology used is radio and the system is known as Walk-Through, the information is collected from the nodes, according to the hub enters the coverage field of terminal nodes and interrogates them one by one. Typically, the hub is a portable terminal that goes storing all the information to later dump this Information to a Data Center.

Based on all this, there is no record of the  existence of any data communication system based on short range radio technologies, which is able to maintain a network of a large number of terminals, which operate without input from external energy, and that are distributed by an area extensive geographical

Summary of the invention

The present invention has been proposed as main objective is to provide effective solutions to needs raised above. This objective has been fully achieved with the system that will be described in what continues, which includes the design and development of a system of data communication based on the use of radio technologies short range for a large number of elements, which operate without external energy input, located in a large geographical area such as a municipality, for an extended period of time (several years). To achieve all this, the applications developed make use of various techniques for optimization of the energy consumption of the device where they reside together with the application of the facilities provided by the technologies themselves Radio used. Similarly, to overcome the challenge that involves the creation of a network with separate elements geographically over a great distance, using technologies that they only cover a few tens of meters, the applications have designed optimizing the amount of energy used to maintain the  links of a node with its neighbors. Techniques are also used to determine the best links to go the way between two nodes separated by a great distance. Due to the high number of elements of the network, this path is not unique nor, when traveling, They produce the same global energy expenditure. Therefore, the designed applications determine the optimal path in each time to take the information to the desired point to the child possible cost.

The topology of the network formed is characterized because each node establishes a certain number of links with its  neighbors depending on the energy expenditure produced by each link and of the expense produced by the node in its usual operation. This energy expenditure, which the node monitors, is variable in time and that is why, each node adapts to the consumption it maintains and configure the network topology in your environment to get to be in use for the time required in advance.

Derived from this way of operation, it it forms a network topology whose basic element is the node. These Nodes maintain links with their neighboring nodes. The number of links maintained, the time windows used to serve those links and, the linked neighboring nodes, are variable in time and decided at all times by the designed algorithms that run Distributed on each node. In the network topology you it also establishes a special node with more benefits than serves as a link to other networks external to the network of object nodes of this invention. These external networks serve to carry the information from the nodes to Management Centers where Store and process all information. In these special nodes routes that a data must follow to reach a node are saved specifically from the network. The set of Central Node plus all elementary nodes that link directly, or through others Nodes, with that one, is known as Subnet. This Subnet Structure It is repeated to cover any large geographical area. The Subnets establish links between them through the nodes basic at the ends of the Subnet so that, after make a transmission to a Central Node of a Subnet, the next transmission can be done to another Central Node of other Subnet if the links of the basic node have been reconfigured Between the two transmissions. In the same way, before the withdrawal or failure of a Central Node, the nodes will redirect their data to another Subnet Central Node. This Subnet Central Node may not exist if the Subnets do not have to link their information with networks external to the Subnet itself.

According to the invention, the following particularities:

i. Communications protocol

These applications, which reside distributed in each node of the network is characterized by the control they exercise in every moment on all the operating parameters that they affect the energy consumption made by the node. Are defined two states and three modes of operation for each node.

States of a node:

- Unconnected state, in which the node has no established link, and

- Connected state, in which the node has the minus a link established with a neighboring node.

The operating modes defined for a node are:

- Neighborhood search mode, in which the node explore the radio space around you to Look for neighboring nodes. When a node finds another neighbor node with which I didn't have a link before, both nodes enter a process by which the link between the two remains established nodes;

- Communication mode, which is entered when a node activates a communication with a neighboring node with which It has an established link. In this mode, the nodes exchange information;

- Low consumption mode, which constitutes the mode default. The node is in this state when it is not in mode Neighbors search or is in communication mode with any of the neighboring nodes. This mode is characterized by using the modes of low consumption that the technology supports and, if implemented by the device, the possibility of being able to turn off the hardware modules that are not necessary to use as is the case of the modules communications when the node is not in search mode or in mode Communication.

In addition to the states and modes of the node, it define a series of variables associated with the modes of operation that control the time the node spends on each operating mode, the window of time that must elapse between two beginnings of the same mode of operation and the expense of energy realized in the execution of each mode of operation. Because a node can have more than one link with the nodes neighbors, these variables are defined for each link. For each link is also defined a variable that indicates the consumption of energy caused by sending an information message to through that link to the Subnet Central Node. For each link is also defined a variable that stores the time elapsed between two consecutive transmissions on that link. Another variable is also defined to store the total time that it takes a message to arrive from the origin node to the Node Subnet Central. For each link, a queue of messages where messages pending to be sent are stored that link For each node, variables are defined to store the node commissioning date, end of service date and The current date and time. You also have a list of links established according to the optimization criteria adopted in in terms of consumption, time or a combination of both variables. This classification will allow us to know at all times what is the most suitable link to send a message to the Central Node of Subnet so that when the time comes to transmit a message is used that link You can also see that there are links "secondary" to the Subnet Central Node and that there are links that have no way to the Central Node of Subnet. He designed protocol works on the basis of values stored in all these variables and making decisions as to to the way of operation according to these variables go modifying

The algorithm starts working since it Gives the node energy. In this first instant, the node initialize all the variables mentioned above and to then it goes on to execute an infinite process loop that will repeat as long as the node has power. In this infinite loop, the node goes through the different modes of operation. In first instead, the node goes into search mode of neighboring nodes during the time indicated by the corresponding parameter. Every time in this process meets another node, the node will add this link, associating the corresponding parameters. Once he node ends this mode of operation, check if it has to attend some of the links established with the nodes neighbors. When this occurs when indicated by the variables associated with that link, the node enters into communication mode with that node. During this mode the nodes exchange information messages and of control. Then they negotiate the following time window in which they will see each other again and finally the communication. Finally, before leaving the communication mode, the node updates the variables associated with the link in terms of Times and consumptions. The algorithm continues checking the rest of the variables associated to the links with the neighboring nodes and with the search mode of neighboring nodes in case you have to attend to those operating modes. This process will be repeated undefined

The algorithm checks the energy expenditure produced in each mode of operation. With this data and knowing the expense that will produce the rest of the modes of operation, the number of times the node can calculate repeat that mode of operation and according to this calculation, decide what is the next instant of time when you will re-enter that mode of operation to get to the goal preset In this way, the node manages to control consumption Total node and optimize energy consumption.

ii. Routing algorithm

There are a lot of mechanisms to route the messages generated in the network to the Central Node of  Subnet Any of these mechanisms that are used do not will modify the functionality of the algorithm, although it will influence the system performance To minimize hardware requirements of the node in terms of storage and in terms of energy expenditure information process, special messages are implemented to collect routes that are generated on each node every time change in the node the optimal link to the Subnet Central Node. Each time this type of message arrives at a node, the node adds to the  message your id and put it in the message queue pending to be sent to the Subnet Central Node. The node Subnet Central collects all these route messages and when wants to send some information to a specific node, the Node Central prepares a message with the route that has to follow the message until you reach that node. Each intermediate node for which pass this message remove your id from the message and put the message in the queue of pending messages from the link that Indicates the following message identification. This process is Repeat until the message reaches the desired node.

Brief description of the drawings

These and other features and advantages of the invention, will become more clearly apparent from the detailed description that follows in a preferred way of embodiment, given by way of illustration only and not limiting, with reference to the accompanying drawings, in the that:

Figure 1 shows the graphic representation of the elements that make up a Subnet of Nodes;

Figure 2 shows a graphical representation of secondary interconnections between subnet end nodes adjacent, and

Figure 3 illustrates a flow chart of operation of the protocol of the present invention.

Description of a preferred embodiment of the invention

If you look at Figures 1 and 2 of the drawings attached, you can see the schematic graphic representation of an example of forming a network of running nodes Distributedly the algorithm that is the subject of this patent. In the Figure 1 shows the elements that make up a Subnet of Nodes The main elements are the Subnet Nodes (1), which as you can see they have been distributed in a geographical area greater than the area that is able to cover each node separately. At moment represented by this figure, each subnet node (1) is executing its algorithm and each of them has established the links (2) with its neighbors that has allowed the evolution of algorithm according to the energy consumption that the node performs in each operating mode. On the other hand, in figure 2 you can appreciate how the end nodes (1) of two adjacent subnets establish secondary connections (4) between them. This topology Network will allow redirecting messages to the Central Node (3) of one Subnet or another. The Figure also shows the connection between the central nodes (3) of the different Subnets, with a Central of Management indicated by the numerical reference (19), through of respective links (20).

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In relation to Figure 3, you can see the Infinite loop of the Process Flow that characterizes the operation of the Protocol object of this request. When start work, the Node Birth process is carried out (5). In this process all the variables that are initialized are initialized. They control the operation of the node. All variables are initialize to null values, except (ccnct) that is set to Highest possible value. The state of the node is not connected. When the node that is born is a Node Subnet Central, the initialization of variables is different since that, it is understood that it is connected, and that its (ccnct) takes a null value, since the energy cost to reach the Central Node It is also zero.

Once this initialization process is finished (5) you enter the infinite loop that controls the execution of the node. First, it asks (6) if the value of the variable (tbn) that determines the time window between two Consecutive processes of search of neighboring nodes (7). To be this value at zero, after the initialization process (5) is go on to run the Node Search process Neighbors (7).

Upon entering this process (7), it is measured and stored the value of the remaining energy, then running the processes of exploration of the surrounding radioelectric space to the node This process is inherent in the technology used, but normally it goes through consecutive processes of transmission of the node identifier and receiving or listening to identifiers of other nodes that are transmitting that moment. When a node is not connected, the algorithm improves this process so that Only do one of the two operations, transmission or reception. With this it is possible to limit the collisions between neighbors not connected, since they are not considered valid links (although the Failure to consider these valid links is considered a improvement of the overall performance of the system in terms of expenditure energetic, the algorithm can contemplate the possibility of establish links between nodes connected. This will lead to islands of nodes not connected to the Subnet Central Node during the network topology training). If during this process (7), the node does not find any neighboring node, it goes to the process of Recalculation of the search time of neighboring nodes (10). If the node matches another node that is in the same process of search for neighboring nodes (8), the process of executing Establish the network link (9). During this process (9), in first it is checked if these two nodes were already connected in a previous link. If so, the communication is interrupted between the two and the process of Recalculating the search time is passed from neighboring nodes (10). The Link Establishment process of network (9) is characterized because each node must modify its variables to enable the establishment of communications between they. Each of them goes through increasing the number of nodes linked (ne), add the identifier of the other in your table of nodes  linked (tne), they exchange the value of their variables consumption of arrival of a message to the Subnet Central Node (ccnct), and then negotiate the following time window (tcn) in which they will see again. Once all this is done, it is interrupted the communication and each of the nodes checks if the link established improves consumption in terms of arrival of messages to Subnet Central Node, and if so, will modify the link that He previously had the best way to the Subnet Central Node (nec). Next, the process of Recalculating the time of   search for neighboring nodes (10). In this process (10) it returns to measure the value of the remaining energy. It is therefore known the consumption produced during the process. With this value, and taking into counts the consumption and timing of the other operating modes that produce energy expenditure, the new instant of time (tbn) in which the node will redo the process of search for neighboring nodes (7). This calculated value is stored in (tbn), and the infinite process loop continues to run.

The next step of the infinite loop consists of a subbucle (13-18) in which everyone is served The established links. For each link, its window is checked of runtime (tcn). If the value of this variable, for one of the links, has reached zero, will indicate that you have to attend to that link and the Process of Establishment of communication (15) with the associated node That expired variable. When this process is executed (15), in First, the remaining energy value is measured and stored, and then it is checked if communication can be established With the expected node. If not, and the other node does not answer calls, a counter of failed attempts will be increased communication with that node (ifc). When this counter (ifc) reaches A preset number of attempts will break that link. This will lead to the update of the variables associated to the link, the number of links established and, if that link was the way to send messages to the Subnet Central Node, you will enter the process of looking for a new path to the Central Node of Subnet Once these steps have been completed, the following will be recalculated time window in which communication will be attempted again to then check the expiration of the times of communication remaining. If communication has been established, in First, the nodes exchange the consumption parameters of each to reach the Central Subnet Node. Node Will check if consumption. exchanged for the other node improves the consumption saved by this one. If so, the links will be changed to send messages to the Subnet Central Node. One time Once the parameters have been checked, the messages that will be exchanged They had to send each one to the other. They will read and they will be processed if they are for the node itself, and if they are not, will be queued for pending messages from the node correspondent. Once these operations are finished, the Consumption made and saving will be updated. Then you will negotiate between the two nodes the following time window where They will communicate again. Once the process of communication with a node (15), the following will be recalculated time window to attend to that link, in case you have to correct it in order to reach the expected service time. This Subbucle will run for each link established. One time Once all the links have been checked, the variable of time to search for new neighbors, in case it has expired and you have to attend that process.

The described cycle will be repeated indefinitely. until you reach the preset life time.

The Protocol on each node tends to add links with the neighboring nodes. It happens that if this situation is not controls, and you want to have a high device life time, the time windows between two consecutive operations will leave enlarging, so the system degrades. To avoid this, the Protocol contemplates self-regulation mechanisms, consisting basically in limiting the number of links allowed to a node When a node has too many established links and start to get off at. benefits, links begin to be removed redundant The criteria regarding the choice of links for your removal, is to first remove the arrival links to the Subnet Central Node that are not selected as the best road. When there is only the best way to the Central Node of Subnet, we will remove those links that for the other node they are redundant links in their link to the Central Node of Subnet When there are no more links than the road to Concentrator, the search time window will increase of other nodes and / or communication with the linked node until The device loses energy. This self-regulation mechanism it is activated when the establishment of a new link occurs. When a link is lost, self-regulation causes them to adjust the times for the rest of the links to occupy the space of Abandoned time

Message Routing Algorithm

The network of nodes that is formed with the execution of these algorithms, is a network composed of basic elements that they have no knowledge of what lies beyond the links neighbors. To get to communicate data between two points of this network, it is necessary to establish mechanisms that route the data from an initial point to another end. There are a crowd of these well-known mechanisms. For this network it has chosen one that, due to its few requirements regarding occupancy of resources of the nodes themselves, is considered as the most optimal. This routing mechanism or algorithm consists of the creation of route collection messages when one of the nodes from the network improve or change your link to the Subnet Central Node. Yes the node has varied its way of arrival at the Central Node of Subnet, prepares a special route collection message and deposits it in the message output queue of the link to the Central Node of Subnet This type of special message is for when a node you encounter a message of this type, just forward it towards the Subnet Central Node by adding to the message that transmits, your identification. Thus, when the message reaches the Node Central of the Subnet, this one can know the path by which he has passed the message to get there. To send a message to a specific node, the Subnet Central Node will only have to make the message with this path you have stored. In this path from the Central Node, each node to which the message, it will delete your message ID and forward it by  the link with the identification indicated in the message. This operation will be repeated for each node through which the message until you reach the destination node. This algorithm will be used. also when a node in non-connected state is Find a node already connected. The new node incorporated into the network will make a special route collection message and what will place in the queue of pending messages to send from your link towards the Central Subnet Node. This link matches the node connected that you just found and incorporate into the network.

Derivations or meanings to the algorithm

Although the communications protocol is thought to extend the service life of the elementary nodes operated with internal energy source, it is not exclusive as that there are nodes that have energy contributed externally to the node. This is contemplated within the algorithm when checking what energy has been consumed in each of the operations performed the node When the energy source is non-finite, the difference in energy before and after executing any operation is zero so that, the node will understand that the consumption when doing the operations is null. With this data, the protocol can shorten as much as allow the rest of the neighbors, the time windows between two consecutive modes of operation. This implies that the greatest contribution of energy by this node influences the largest benefits that the protocol can give within the zone of influence of that node with external energy. This situation too it helps the preservation of the energy of the neighboring nodes to him and that, when there is a node with non-finite external energy input, the algorithm in the neighboring nodes rearranges the links so that the Road to the Central Node is this node with non-finite energy. This occurs because operations with this node are less expensive. in time and consumption than if the messages passed through nodes with internal energy.

The protocol is designed to support the introduction of delay time parameters between transmissions next to the consumption control performed by the nodes in the transmission. With the control of these time variables of delay, the protocol implements the time control of transmission, with what you can choose as the best link, not just the that consume less energy, but also the one that takes less time to Get to the destination

An exhibition of the functionality associated with each of the organizational chart blocks shown in Figure 3, which is as follows:

5

Birth of the Node

6

Expired node search time neighbors? If not

7

Look for neighboring nodes

8

He has found any node? If not

9

Establish network link

10

Search time recalculation of neighboring nodes

eleven

Decrease node search time neighbors

12

n = Number of active links

13

N = 0? If not

14

Expired communication time with node n?

fifteen

Establish communication with node n

16

Recalculation of communication time with node n

17

Decrease communication time with node n

18

Decrease n

Also, in relation to abbreviations used in the description, the following is clarified respective meaning of each of them:

ccnct

Consumption of sending a message to the Central Node of Subnet

ccnc (n)

Consumption of sending a message from the node to the Central Subnet Node, through link n.

tbn

Time between the execution of two Consecutive processes of Node Search.

ne

Number of nodes with which a link.

tne

Table of the identifiers of the Nodes with the That a link is maintained.

tcn (n)

Time between the consecutive execution of Two processes of Communication with node n.

nec

Link to the Subnet Central Node.

ifc

Number of failed attempts to connect to the node n.

It is not considered necessary to make the content of this description for a subject matter expert can understand its scope and the advantages derived from the invention, as well as develop and implement the object Of the same.

However, it should be understood that the invention has been described according to a preferred embodiment thereof, so which may be subject to change without implying any alteration of the basis of said invention, all of them within its scope, as defined by the claims that follow.

Claims (3)

1. Protocol for the construction of wide area data communication networks based on short-range radio technology, for application to a data communication system for applications that require a large number of autonomous, fixed or mobile elements, distributed by a large geographical area, with optimization of global energy expenditure, that is, without external energy input, which is characterized by the establishment of a network topology formed by a multiplicity of nodes, each of them trained to establish a number of links with other neighboring nodes depending on the energy expenditure produced by each link and the expense produced with its normal operation, this energy expenditure being variable over time, and therefore the node being able to adapt the consumption and configure the network topology in your environment so that your energy capacity allows you to be in use for a preset period of time acid because the various parameters related to number of links maintained by the nodes with their neighbors, the time windows used to serve those links, and the number of linked neighboring nodes, are variable in time, and depend at each moment of algorithms designed for this purpose, which run distributed on each node, and because in the established topology, there are nodes  special, with greater number of benefits, which perform the link with other external networks responsible for carrying the information to Central Management, where it is stored and processed. 2. Protocol according to claim 1, characterized in that each of said special nodes is capable of storing the routes that must be followed by data to access a specific node. 3. Protocol according to claim 1 or claim 2, characterized in that each node is capable of adopting two functional states, namely, a) a first non-connected state, in which the node has no established link, and b) a second connected state, in which the node has at least one link established with a neighboring node, and because each node is affected by three modes of operation, defined by: a) a search mode, in which the node explores the radio space around it for the search of neighboring nodes, so when it finds another node with which there is no previous link, both nodes enter in a process of establishing a link between them; b) a mode of communication, in which a node establishes a communication with a node with respect to which there is a previous link, for the mutual exchange of information; and c) a low mode consumption, constituting the default mode, in which it is located  when it is not in any of the other two modes, and susceptible to incorporate means to turn off hardware modules other than necessary to use at those times.