DE10141511A1 - Self-organization of sub-networks in mobile ad hoc telecommunications networks involves forming groups of users that are moving in similar directions at similar speeds - Google Patents

Abstract

The method involves forming groups of users in a communications network, especially an ad hoc network for mobile users, whereby the users have different patterns of movement. The users that are moving in similar directions at similar speeds form a group. Time variations in receiver field strengths can be compared between users and users with similar time variations formed into groups. Independent claims are also included for the following: a subscriber equipment in a communications network.

Description

In addition to radio networks in which the mobile subscribers via Ba stations are connected to a core network, and at which carries a lot of the information over cables is known, radio networks in which the individual parts participants are interconnected and self-organized to forward the information. Such networks are always used where an infrastructure is not is available. Commu is an interesting field of application nication in the event of a crisis, especially between mobile workers Units that pertain to an area wagon that none Infrastructure. Since next to the Sprachkommu nication of information exchange in digital form always more importantly, these networks must also be able to be to exchange large amounts of data. Below are preferably packet-based telecommunications networks with considered mobile devices or relay stations, the same can continuously form dynamic networks (mobile ad hoc Networks). For establishing communication connections must connect routes between the end devices of the communication cation participants are manufactured. Because the topology of the network can change quickly, e.g. B. if the mobile end devices are carried by pedestrians in a pedestrian zone or in moving vehicles, the routes must frequently recalculated or used several routes at the same time and be monitored. Due to the frequent reorganization of the Network and the recalculation of the routes is reduced the transmission capacity of the network. A problem that occurs particularly in packet-oriented networks an unacceptable QoS (Quality of Service) as a result of Reorganization of the topology.  

So far, there are essentially two different processes classes [E. M. Royer, C.-K. Toh, "A Review of Current Rou Protocols for Ad Hoc Mobile Wireless Networks ", IEEE Personal Communications, April 1999, pp. 46-55]. Here han it is a table-based routing method and quel Lenin-initiated on-demand processes. In the former procedure tries to get current routing information from each node manage all other nodes. Every knot has to do this Manage one or more routing tables. Changes in the topology are propagated and lead through the network for an update of the routing tables. The different ver drive differ in number of tables and type and How to transfer changes in network topology. Use the well-known table-oriented routing methods the Bellmann-Ford algorithm, whereby each participant has one Table with all routes managed to possible destinations. This information is either completely on the network transmitted, or only the information is propagated, that have changed. In the routing tables, next to the destination also has a unique number, based on which it can be determined whether a circular relationship be stands. In a hierarchical network, like a cluster Gateway switch routing, it may be possible that only the cluster head manages a routing table then forward the information if necessary. Should ever but change the allocation of the cluster head, so the new cluster head provides all the necessary routing information demand. To keep the structure as efficient as possible, it is therefore necessary especially with very mobile networks, that all participants have both the membership information as well as manage the routing information in parallel. Next the described table-based routing procedures the wireless routing protocol. With this procedure each node in the network manages four tables: one dis dance table, a routing table, a connection cost belle and a table in which the number of attempts one Transfer is entered. When the routes change,  only the immediate neighbors transmit an update. The Neighbors save the new connection after the update formations and possible new paths or nodes. By bet Participants learn about the news from their night barn. The advantage of this algorithm is the recognition of cycles based on the distance information to the night barn.

The second class of processes is characterized by that new routes are only created if they are from a Source are needed. Every time there is a route fin initiation process. Another process then ensures maintaining or modifying the route. If the Connection can no longer be held or no longer the route is deleted.

With this method, a request is made into the network sent by all participants to all sorts of other Participant is propagated. Here, counters and identi used to avoid cycles. When building Each participant saves the previous route Participant from whom he receives the request for a new route ten. This allows the answer to correct be returned. After the target participant has been found the one who answered, the path becomes through the other held the participant upright. The path will only last as long maintained until either an appropriate message is sent to dismantle the path or through some Period no information has been sent on this path.

In another method, dynamic source routing, who which all routes have been learned and updated periodically. Should one Route is not known, so a corresponding process started making a request to all neighboring participants sends, asking whether the neighbors know the route NEN. If the neighbors don't know the routes either, So you enter your address and send the package to everyone  Neighbors further. A request is ended if either The goal was reached or a participant was found who knows a route to the destination participant. The new route is then to all participants who have entered their address, returned.

Another algorithm called TORA is based on the concept the connection reversal. The core approach of this algorithm is the localization of control messages to a very small a set of nodes that are near a topology change occur.

In associativity-based routing, each participant sends peri odisch a signal message to all participants in his Are neighborhood, where participants have a counter for count up this neighboring station. The routing takes place based on the counter values. The higher the counter, the more The connection is more secure. When establishing the connection the counters accumulated, then conclusions about the best Connection to meet.

The signal stability routing algorithm takes this into account Quality of the connection, d. H. the signal stability in order to to calculate a route based on. Here, for the Find the routes using dynamic algorithms and Ta bark for managing the routes found in this way.

However, since both approaches have a significant administrative burden wall induce, one has gone over to cluster or Form groups that include a control participant or con troll node that manages the route information tet. This can be both a static process (table-oriented) as well as a dynamic process act (on demand). The groups thus formed hire Subnetwork represents. Within these subnetworks is therefore the Route determination and route recalculation with considerably less Effort connected, so table-based procedures that  optimal use of resources in static topologies, be can be used. For those from the Clusterhead Gateway Switch routing known approaches [C.-C. Chiang, H.-K. Wu, W. Liu, M. Gerla, "Routing in Clustered Multihop, Mobile Wireless Networks with Fading Channel ", Proc. IEEE SICON 97, Apr. 1997, pp. 197-211; M. Gerla, J. T.-C. Tsai, "Multiclus ter, mobile, multimedia radio networks ", ACM-Baltzer Journal of Wireless Networks, Vol. 1, No. 3, pp. 255-265, (1995)] in addition to normal participants, there are so-called gateway Participants and clusterhead participants. The clusterhead Participants allocate the bandwidth and organize it Network. They also have the task of providing information that cannot be delivered in the network to which gateway Forward participants. The gateway participants regulate the Communication with other clusters. Choosing the gateway Participant follows the following procedure: A node or Participant who hears more than two clusterhead participants or receives data from them is a gateway user. The selection of the clusterhead participant can be done under different models. On the one hand, the participant selected the most connections to all participants in a cluster, or that has the least identification tion number in a cluster, with the participants one have a running, unique identification number.

The object of the present invention is a method and To provide devices that are optimized together allow the creation of a cluster or group.

This task is solved by a procedure and device gene with the features of the independent claims. Further Refinements can be found in the subclaims.

The present invention is based on the observation that in areas where a high network load was expected ten, the mobile network subscribers are divided into groups can be, whose members are in similar directions  and move at a similar speed. Examples of this are vehicles on different lanes or Pedestrians moving in opposite directions or stand. These groups can form subnetworks Topology because of the low relative speed of the individual group members changes slowly. Here fin the members of the individual subnetworks by temporal change in the reception field strength of that of the others Compare signals sent to members. Transmitter with ger temporal change of the received signal strength are as Considered members of their own subnetwork. The commun cation from subnetwork to subnetwork takes place via so-called "Subnetwork relays" or gateways that can be found that they are as short as possible within the subnetwork Have connections to the individual members. This Communication from "Subnetwork Relay" to "Subnetwork Relay" requires less route calculation effort because of their number and thus the resulting network of "subnetwork relays" is much smaller. Occur for this communication preferably source-induced on-demand routing in Fra ge.

Compared to the prior art, such as. B. the cluster head Gateway switch routing is used in the present invention Subnetworks (clusters) not necessarily due to the stati spatial proximity or reception strength. in the Contrary to associativity-based routing or signal Stability routing uses the present method Stability of neighborhood relationships between nodes not for routing, but clusters in subnetworks.

In the present process, the parts form in detail Participants whose temporal change in the field strength a be agreed to not fall below a threshold, a group. The The threshold value can of course be adjusted dynamically The threshold can also depend on how big is a cluster. Should too few members or part  participants in a cluster, this is smoldering to adjust the lenwert.

In contrast to the known methods, the relay Participants communicate from group to group and the same bandwidth management and group or Cluster Management. In an alternative embodiment, However, special cluster management participants like her have already been described above. Next these cluster management participants are then relay- Subscriber or gateway subscriber required. The selection this participant can use different methods consequences. Some of these methods have already been described above wrote.

In the preferred embodiment, after the choice of Ga gateway subscriber, which is therefore the shortest possible connection for all participants in a group, for routes the information packages of the other participants are a source induced on-demand routing. It is to point out that the choice of the participant on below different metrics. So z. B. the sum all ways are taken and according to different procedures be averaged; the sum of all ver binding times or the average throughput ge be chosen. Alternative metrics are also available bar.

In a preferred embodiment, the relay participant also for bandwidth management, especially for Frequency or time slot management. Concerning. the Functionalities will be particularly on the above referred to prior art [C.-C. Chiang, H.-K. Wu, W. Liu, M. Gerla, "Routing in Clustered Multihop, Mobile Wireless Networks with Fading Channel ", Proc. IEEE SICON 97, Apr. 1997, pp. 197-211; M. Gerla, J. T.-C. Tsai, "Multiclus  ter, mobile, multimedia radio networks ", ACM-Baltzer Journal of Wireless Networks, Vol. 1, No. 3, pp. 255-265, (1995)].

Specifically, a second participant requests a commu The relay subscriber intends the required bandwidth then a communication link after the assignment build up. Should the communication partner in the same Cluster or the same group, so the connection can also be set up directly to the participant. In a alternative embodiment can be provided that the Connection must always be made via the relay subscriber whether it is a participant in the cluster or acts outside the cluster.

The networks can be of different types Trade networks. So the network can be packet-oriented or be connection-oriented, be a TDMA or CDMA Act network. Possible structures are e.g. B. GSM, GRPS, UMTS.

The technologies mentioned are preferred in a mobile Ad hoc network or in a packet-oriented multi-hop Radio network used.

Furthermore, the participants, especially the relay Participants, be able to connect to a base to build station, which usually connects to the Fixed network enables.

Further components of the invention are participants who in are able to analyze the behavior of other participants to join a group or cluster countries. These participants have means, in particular computing units and receiving measurement units that reflect your own time Record movement behavior in order to compare this with the movement to compare the behavior of other participants  Based on this comparison, it belongs to the group determine which has the highest match.

In a preferred embodiment, changes over time analysis of the reception field strength of other participants to join the group of participants, de the change is small or to form a group, which is the least temporal change in the reception field strength Has. In another embodiment, the movement vectors determined, e.g. B. by motion sensors in the Re gel gyristors or GPS signals. In another version The distance vectors of the participants are also used taken into account, if possible, the participants in a group to unite, which are close to each other. Computing means, especially microprocessors or special ones Chips that have low power consumption and that are on the calculation and comparison of vectors are optimized, after comparing the motion vectors of the participants have received the individual deviations.

So that each participant functions as a relay participant can take over, additional funds are necessary, in particular which enable routing. In a preferred embodiment The function of a relay participant is realized siert, whereby there are other means that a route of information about other subscribers or base stations allow. Depending on the routing method, there are different Means necessary. In a preferred embodiment an on-demand method is used for routing. As a realization This process is usually a processor and a memory area is necessary in which the information is stored that are needed to find a route. It however, special chips are also conceivable that perform these tasks perform optimized. Usually are in this store area at least the neighboring relay participants of the other their groups or clusters, with the help of their information to receive onen from the participants of the neighboring groups  are. Furthermore, the relay participant will ver a table in which all participants of the cluster or group are filed. Based on this information, the participants to be switched using the other relay Participants, e.g. B. by calculating the shortest path, the target participant. This process can be either act as a distributed process, d. H. each relay Participant takes on a subtask of this process and provides the result, d. H. the partial route back, or it only data (possible participants of the other group pen) transmitted to the output relay subscriber, using de he calculates the best route.

However, it is not excluded that others too Routing procedures are used (see above), in particular re procedures that use routing tables, these Ta bark a series of routes depending on the destination manuals. For routes for which there is no destination, there is an or several standard gateways are provided to which the packets know be sent.

In a preferred embodiment, the participants also funds to implement bandwidth management to lead. This is particularly important if only be Restricted resources are available and QoS ensured must become. Depending on the form and type of network, Mit tel used depending on the requests by a corresponding protocol to the other participants a certain Provide bandwidth. Here it is also necessary that this bandwidth is also between the relay participants is provided so that there is no bottleneck when transporting on the information arises. This requires an equivalent protocol between the participants. In a possible Chen embodiment, the route can be based on the required Bandwidth can be calculated. So the bandwidth needed used as a metric to determine the best way or the best to calculate the route. The range is determined by the zutei  frequency bands or time slots. The Allocation is based on the maximum available band width. However, this is always from the weakest verb segment as the maximum value. After the request of a participant depends on the route to be selected allocated the maximum bandwidth, but not the To requirement of the participant exceeds.

In a further embodiment, in addition to the relay Participants provided additional gateway participants who connect to other groups. This gateway Participants are often arranged around the edge of a network to be able to establish the connection between two groups.

In the following, the possible structure is shown on the basis of a figure network. It shows:

Fig. 1 shows an ad hoc network with three clusters, which have several participants, the participants each having a different Bewegungsvek tor, with relay participants, which are assigned to the group.

The single figure shows an ad hoc network 10 , which comprises a number of participants 17 , each with different directions of movement 16 . The directions of movement 16 are identified by corresponding vectors. The participants 17 , which have the same direction of movement 16 , are grouped together to form a group or a cluster 12 , 13 , 14 . The cluster is identified by a dashed line. Each cluster generally has a number of relay subscribers 18 which establish the connections to other clusters or to a base station 11 which are generally connected to a landline network (not shown). The present figure shows two connections 20 and 19 , where connection 19 via three relay subscribers 18 leads to base station 11 . The relay participants are responsible for forwarding (routing) the information. It should be noted that a cell boundary 15 is exceeded in the connection between cluster 12 and cluster 13 . This cell boundary is usually arranged so that there are no frequency overlaps. The second connection 19 merely ensures an information flow within two cells or clusters, the subscriber sending information about a subscriber of the cluster 13 via the relay subscriber of his cluster 14 .

Claims (19)

1. A method for forming groups of participants in a communication network, in particular an ad hoc network, which is designed for mobile participants, the participants having different movement patterns, characterized in that the participants form a group which is divided into one move a similar direction at a similar speed. 2. The method according to the preceding claim, characterized characterized that by comparing the temporal Change the reception field strength of other participants Groups are determined, with the participants forming a group form, the temporal change is small. 3. Method according to one or more of the preceding Claims, characterized in that the commu Application from group to group takes place via relay participants. 4. The method according to the preceding claim, characterized characterized that as a relay participant Participant is determined, the shortest possible connection to all participants in a group. 5. Method according to one or more of the preceding Claims, characterized in that for the Be calculation of routes via relay participants source-induced On-demand routing methods can be used. 6. Method according to one or more of the preceding Claims, characterized in that a first Participants in a bandwidth management group, especially for frequency and / or time slot management too is permanent, with a second participant in a communication cations intent of the first participant the required bandwidth  requests to then after the assignment a communication ver build a bond. 7. The method according to the preceding claim, characterized characterized that the relay subscriber for the Bandwidth management is responsible. 8. Method according to one or more of the preceding Claims, characterized in that the commu nication within the group not necessarily via the Relay participant takes place. 9. The method according to one or more of the preceding Claims, characterized in that it is a packet-oriented network such as CDMA, GRPS, UMTS to a connection-oriented network or a time slot oriented like GSM. 10. The method according to one or more of the preceding Claims, characterized in that it is a mobile ad hoc network or a packet-oriented one Multi-hop radio network. 11. The method according to one or more of the preceding Claims, characterized in that the relay If necessary, participants connect to a base station Establish tion that enables a connection to the fixed network. 12. Participants in a communication network, the relay Has subscribers for routing information, each Participants listened to a group and preferred the participants show different movement behavior, characterized by means, that record your own temporal movement behavior in order to this with the movement behavior of the other participants compare to compare the affiliation based on this comparison  to determine the group that has the highest match has. 13. Participant according to the previous device claim, characterized by means of the temporal change analyze the reception field strength of other participants, to join the group of participants whose changes is small or to form a group that has the slightest temporal change in the reception field strength. 14. Participants according to one or more of the previous ones Device claims, characterized by means that the motion vectors and the distance vectors of the participants to compare. 15. Participants after one or more of the previous Device claims, characterized by means that realize the function of a relay subscriber, with white There are more means available to route information allow to other subscribers or base stations. 16. Participants after one or more of the previous Device claims, characterized in that it is a mobile ad hoc network or a paketori Entity multi-hop radio network. 17. Participants after one or more of the preceding Device claims, characterized in that for the calculation of routes via relay participants source-induced on-demand routing processes the. 18. Participants after one or more of the previous Device claims, characterized in that a first participant in a group for the bandwidth measure management, especially for frequency and / or time slot Management is responsible, with a second participant at  an intention to communicate from the first participant requested bandwidth, then after the allocation a Establish communication connection. 19. Participants after one or more of the previous Device claims, characterized in that the relay participant is responsible for bandwidth management is.