MXPA06004668A - Method for the transmission of information in a communication system using a path - Google Patents

Abstract

The invention relates to a method for the transmission of information in a communication system with a number of nodes (A, B, C, D, E). At least one node (B, C, D) receives a message (MES 1), comprising the details of a path (A?B?D?E), running from a source node (A), through the at least one node (B, C, D), to a target node (E). According to the invention, the at least one node (B, C, D), using the details of the at least one path (A?B?D?E), stores identification information concerning the both nodes (A, B, C, D, E), adjacent to the at least one node (B, C, D), along the at least one path (A?B?D?E) and transmits the message (MES1) further along the at least one path (A?B?D?E, A?C?D?E). The invention further relates to a node (B, C, D) in a communication system, for carrying out said method.

Description

METHOD FOR THE TRANSMISSION OF INFORMATION IN A COMMUNICATION SYSTEM USING A PATH FIELD OF THE INVENTION The invention relates to a method for transmitting information in a communication system with a plurality of nodes. Furthermore, the invention relates to a node in a communication system. BACKGROUND OF THE INVENTION For the communication or for the transmission of information, a plurality of communication systems of different types are known. For example, in radio communication systems, information is transmitted (such as voice, images, video, SMS (Short Message Services), MSM (Multimedia Message Service) or other data) with the help of electromagnetic waves through a radio interface between source and target nodes. The nodes of a radio communication system, depending on the specific configuration of the radio communication system, can be different radio subscriber stations, access points or base stations. The radiation of the electromagnetic waves is carried out here with carrier frequencies, which are in the frequency band provided for the system in question. Radio communication systems are often configured as cellular systems, for example in accordance with the GSM (Global System for Mobile Communication) or UMTS (Universal Mobile Telecommunications System) standard with a network infrastructure consisting, for example, of basic stations, devices for the control and management of base stations and other network devices. In addition, those cellular communication systems, hierarchical by radio of broad organization (supra-local), there are also local wireless networks (WLAN, Wireless Local Area Networks) with a range of radio coverage usually clearly spatially limited. The cells covered by the radio access points (AP: access point) of the LAN with a diameter of up to a few hundred meters, are reduced compared to the usual mobile radio cells. Examples of different standards for WLAN are HiperLAN, DECT, IEEE 802.11, Bluetooth and WATM. In an Adhoc mode of a radio communication system, the radio stations can communicate with each other through one or several jumps (hop or miltihop), without mediating devices such as, for example, base stations having to be connected in an intermediate manner. or access points. If a radio station intends to transmit data to another radio station outside its radiation coverage area, as is often the case in an Ad oc mode, then a path between the radio station as a node must be determined source and the receiver of the data as the target node. A trajectory extends through one or several nodes, which during the transmission of data, retransmit the information between the base node and the target node. The nodes of a path in a radio communication system are neighboring radio stations, which can communicate with each other by means of a radio transmission. A procedure frequently used for the decentralized determination of paths (routing) in a communication system is the DSR (dynamic source routing) procedure. In this case, the nodes of the communication system determine a path between a source node and an objective node, in which the results of the procedure know both the source node and the object node of one or more complete trajectories. Each message sent by the source node to the target node includes the data of a given path such that the nodes of the path can transmit the message according to the path data. The trajectory data to be used in each message, however, represent a large display of signaling and, therefore, an inefficient use of scarce transmission resources. An alternately used routing procedure is the AODV procedure (Route of ad-hoc distance vectors per request), with which as result the source and objective nodes do not know the complete trajectory but mainly the adjacent nodes along the trajectory. In addition, after completing the determination of the trajectory, each of the nodes of the trajectory knows its adjacent node along the trajectory in such a way that in the case of transmission of a message from the source node to the target node, the message does not contains data of the trajectory to be used. A disadvantage of the AODV process is that it can not alternatively use a plurality of trajectories. Furthermore, in the case that the determined trajectory can not be used anymore for the transmission of messages, a new procedure for the determination of the trajectory must be executed. On the contrary, resources are saved when several trajectories are obtained as a result of the determination of the trajectory, in such a way that the determined trajectories can be used for a longer period. SUMMARY OF THE INVENTION The invention proposes the task of presenting a procedure which makes possible the transmission of messages between a source node and an objective of a communication system with a saving of the transmission resources. In addition, a node must be shown to perform the procedure. This task is solved with respect to the process by means of a method with the features of claim 1. Advantageous embodiments and embodiments are the subject of the dependent claims. In the method for transmitting information in a communication system with a plurality of nodes, at least one node receives a message that includes data from at least one path that extends from a source node through at least one node to a node. target node. According to the invention, the at least one node stores the identification data referring to the two adjacent nodes of at least one node along at least one path, using the data of the at least one path. In addition, at least one node transmits the message along at least one path. The communication system can be, for example, a radio communication system, or also a communication system connected by cables. The nodes of the communication system are shaped correspondingly to the communication system, in a radio communication system the nodes can be subscriber radio stations, a repeater or other devices on the network side. A path of the communication system extends from a source node to a target node. If a message is transmitted through the path, then the source node is the sender of the message, and the target node is the receiver to which the message is addressed. This forms a trajectory from the source node to the target node, as well as to the other nodes of the trajectory, which transmit the information between the source and target nodes. The data of a trajectory can contain information about the source node, the target node, as well as nodes of the trajectory, through which the trajectory extends. According to the invention, a message is used which contains the data of at least one trajectory, therefore it can be designated as a trajectory message. In addition to the data of at least one path, the path message may, however, contain other information, such as useful and / or signaling information. The at least one node, which receives the path message, stores identification information of its adjacent nodes along a path. That identification information may contain at least one node of the path message directly or indirectly. If the path extends only for one node, then the adjacent nodes of that node are the source node and the target node. When there is a plurality of nodes in the trajectory, the adjacent nodes can be the adjacent node and another node, or two nodes, or a node and the target node of the path. The identification information allows the node to be clearly directed to at least those nodes in its immediate vicinity that comply with the identification information. However, it is also possible that the identification information contains a clear address of the node in question within a part or of the entire communication system. The identification information may be assigned to the nodes in question temporarily or permanently. In another embodiment of the invention, the message including the data is sent in the at least one path from the source node of the at least one path. The original sender of the trajectory message is therefore the target node of the trajectory. The at least one node, which receives the path message and on the basis of this stores the identification information of its adjacent nodes, can receive the path message either directly from the source node or also from other transmitting nodes of the path message. Advantageously, at least one other message is transmitted, which does not contain data on the path to be used for the transmission of at least one other message, from the source node through at least one path to the target node using the stored identification information. . Due to the previous storage of identification information of the nodes of at least one trajectory, messages can be transmitted through that at least one trajectory, without these messages having to contain data on the trajectory used. According to another embodiment of the invention after a failed transmission of the other message from the source node through at least one path to the target nodes, a message that does not include data on the path used for the transmission, a message is transmitted that it covers the data of at least one path from the source node of the at least one path. A failed transmission means that the message in question does not reach the target node. The transmission of the other messages, which do not include data of the trajectory used, is unsuccessful and therefore is not complete, but is carried out at most partially. Due to the failed transmission, a path message is sent again. The trajectory message advantageously includes, in addition to the path data, also the content of that message whose transmission failed. Advantageously, at least one path is determined with the help of a device that determines the relationships between the nodes of the communication system. The radio communication system in the case of such a device may be, for example, a base station or a device linked to a base station. The device determines the path especially when requested by the source node. After the determination of the trajectory, the device can then transmit data on the determined trajectory to the source node and this inputs that data on the trajectory into a trajectory message and transmits the trajectory message to the adjacent nodes along the trajectory. Alternatively to this central determination of the path through a device using the topology of the network, the at least one path can also be determined through nodes, which do not have information about the topology of the entire network. An example of this is the determination of trajectories through equivalent nodes of an Adhoc system, for example in accordance with the DSR procedure. In one embodiment of the invention all the nodes through which a path extends, receive the message that includes the data of at least one path. In addition those nodes store identification information referring to the nodes adjacent to the node in question along the path. In particular all those nodes of the trajectory receive the trajectory message sequentially through a retransmission of the trajectory message through the previous nodes along the trajectory. It is advantageous that the at least one node receives a message that includes data from a path that extends through at least one node and stores the identification information of the corresponding two adjacent nodes to at least one node over several trajectories In this case the trajectory message contains the data of a plurality of trajectories, after which the at least one node after receipt of the path message stores a plurality of pairs of adjacent nodes along a path. Alternatively to the use of a trajectory message with the data of a plurality of trajectories may also use a plurality of trajectory messages, which include the data of a trajectory. The indication of several trajectories, independently of whether it is carried out in one or several trajectory messages, has the advantage that in case of transmission problems along one of the trajectories, another trajectory can be used to transmit the messages . In another embodiment of the invention, after receipt of the message transmitted from the source node to the target node of the at least one node path, with reference to which at least one node has not stored any identification information throughout of the nodes adjacent to the at least one path, the at least one node stores identification information of that node along the nodes adjacent to the at least one path. In this case the at least one node recognizes that it has received a message which must be transmitted from the source node to the target node, from another different node to the adjacent nodes along the path between the source and target nodes. Thus the at least one node stores identification information of that unknown node as an adjacent node along the path, whereby this new identification information erases the identification information that was previously stored about the node adjacent to the source node in relationship to the trajectory between the source and objective nodes. By continuing to transmit or send a message to the source nodes, the new identification information can be used to address the adjacent node. Preferably the at least one node, after it has received a data from. another path other than at least one path, between the at least one node and the target node, stores identification information of the at least one node along the adjacent node of the other path. In this case, the at least one node stores identification information of a new adjacent node along another path in the direction of the target node. That new identification information can replace the identification information hitherto stored, and which refers to the adjacent nodes in the direction of the target node with respect to at least one path between the source and target nodes.

During a future transmission of information to the target node, the new identification information can be used for addressing. This procedure corresponds to an update of the path that will be used during the transmission of messages from the source and target nodes. The at least one node can receive the data from the other path, for example from a device having a scheme of the topology of the network. The aforementioned task with respect to a node in a communication system is solved by means of a node with the features of claim 10. Advantageous embodiments and embodiments are the subject of the dependent claims. The node has means for receiving a message that includes data from at least one source node through the node in a path that extends to a target node. According to the invention, the node also has means for storing identification information of both adjacent nodes to at least one node along the at least one path, as well as means for transmitting the message along at least one path. In another embodiment of the invention, the node also has means for storing identification information of a node, from which it receives a message directed from the source node to the target node of the at least one path, and with reference to which it has not stored information. of identification as along the node adjacent to the at least one path, such as along the adjacent node of the at least one path. One embodiment of the invention the node furthermore has means for receiving data from a different path than the at least one path, between the node and the target node, as well as means for storing identification information of a node as an adjacent node throughout of the other trajectory. The nodes according to the invention in a communication system are particularly suitable for carrying out the above-described method, which is also described in the dependent claims. For this the node can present other suitable means.

BRIEF DESCRIPTION OF THE FIGURES The invention will be described below with the help of an exemplary embodiment. In which: Figure 1 shows a schematic representation of a first embodiment of the method according to the invention in a communication system, Figure 2 shows a schematic representation of a second embodiment of the method according to the invention in a system of Figure 1 shows Figure 3 shows a schematic representation of a third embodiment of the method according to the invention in a communication system of Figure 1, Figure 4 shows a schematic representation of a fourth embodiment of the agreement procedure. With the invention in a communication system of Figure 1, Figure 5 shows a schematic representation of a fifth embodiment of the method according to the invention in a communication system of Figure 1.

DETAILED DESCRIPTION OF THE INVENTION Figure 1 shows a communication system consisting of the nodes A, B, C, D and E. The node A which is then the source node, performs the transmission of messages to the node E, to Then the target node. The nodes that can communicate directly with each other are linked by lines or arrows. Since direct communication between the source node A and the target node E is not possible, a path between the source node A and the target node E before the transmission of messages must be determined. A possible path between the source node A and the target node E extends through the nodes C and D, and another path extends through the nodes B and D. The communication system can be, for example, a communication system by cellular mobile radio, in which a path between a mobile subscriber station and a base station that is outside the range of the radiation of the mobile station must be determined. Alternatively, the target node can be, for example, an access point of a WLAN. Another possibility is that nodes A, B, C, D and E represent radio stations of an ad hoc system.

In FIG. 1 it is assumed that the source node A knows the path A? B? D? E towards the target node. This knowledge may have been obtained by node A, for example, through an earlier DSR process. Here the source node A transmits a request for the determination of the path between the source node A and the target node E, the request includes identification information of the source node A. That request is transmitted through the communication system. Each node that receives the request adds its own identification information and retransmits the request. The request finely reaches the target node which thus knows the complete path. Send a request along the determined path. For this, the response includes the determined trajectory data, in such a way that the nodes recognize the trajectory to which the nodes must transmit the response. Alternatively to the described procedure of decentralized determination of the trajectory, it is possible for a device, such as a device on the network side of a cellular radio communication system, to determine the trajectory when the source node A requests it. For this the device uses the knowledge of the network topology that was previously transmitted by the node. The data on the determined trajectory is then sent to the source node A. The source node A in figure 1 sends to the B node an MESl message, which consists of information DATA1 and the data of the trajectory A? B? D? E. It stores in an SB memory, the identification information of the nodes adjacent to it in the direction of the source node A, that is, the source node A and the nodes adjacent to it in the direction towards the target node E, that is node D. Then the node B carries the message MESl to the adjacent node in the direction of the target node E, which is the node D. It stores in the memory SD, the identification information of the node adjacent to the node in the direction of the source node A, that is the node B, and of the node adjacent to it in the direction of the target node E, this is node E. In addition, the node D transmits the message MESl to the target node E, which stores in the memory SE the identification information of the node thereto adjacent to the source node A, this is the node D. Also the source node A stores in identification information of the node adjacent to the node in the direction of the target node E, that is node B. So both the source node A, as well as also the target node E, a yes as nodes B and D know the trajectory of their adjacent nodes for the next hop in the direction of the source nodes A and / or in the direction of the target nodes E. The identification information corresponding to the adjacent nodes, nodes B, D and E obtained from the indication of the path A-? B? D? E of the MESl message. Figure 2 shows the transmission of an MES2 message from the source node A to the target node E. The message MES2 consists here of information DATA2 and of identification information of the source node A and the target node E. The data of the target node E is necessary since the nodes B and D with the help of that information decide to which nodes the message MES2 will be transmitted. The data of node A is advantageous for eventual failure warnings. The MES2 message does not include data on the path used for the transmission of the MES2 message. This leads to a saving of transmission resources since a part of the information DATA2 in the total range of the message MES2 is greater than for example the part of the information DATA1 in the total range of the message MESl. The nodes B and D of the path A? B? D? E with the help of the message MES2 recognize that the message MES2 has been determined for the target node E. Since the nodes B and D have stored the identification information corresponding to the adjacent nodes D and E along the path A? B? D? E, transmit these the message MES2 in accordance with the stored identification information. Then a problem occurs when the message MES1 is lost, which contains the data of the trajectory A? B? D? E, this is when not all the nodes B and D of the trajectory receive the message MESl. In FIG. 3 it is assumed that the transmission of the MES1 message between the node B and the node D fails. Thus, the node D has not stored identification information relating to the adjacent nodes along the path A? B? D ? E If the node D receives the message MES2 from the source node A for the target node E, then the node D does not know to which node the message MES2 should be transmitted. If the node D receives a message of that type, which is directed to the target node E, without that message containing data on the path used, then the node D issues an error message ERROR, which is transmitted back to the node source A through node B. Here it is advantageous when the message contains a data field, which makes it possible to identify the node from which the message has been received, that is from node B. This guarantees that there is a valid path of return to source node A, which can be used to send the error message ERROR. This type of data fields should be used in particular during the transmission of the first warning through a trajectory, a message that does not contain data on the trajectory to be used. After receiving the ERROR error message, the source node A transmits an MES3 message, which includes the DATA2 information that an error has occurred during its transmission, and the indication of a path A? B? D? E. The nodes B, D and E as shown in Figure 1 can store the identification information of their adjacent ones along the path. However, no new storage should be made through node B, since it contains identification information of its adjacent nodes already before the transmission of the MESl message. The following message can then be transmitted from the source node A again without indicating the path used. In Figure 4 the case is represented that the source node A not only knows the trajectory A? B? D? E, but also the trajectory A? C? D? E. After receiving the error message ERROR from the path A? B? D? E the node A decides to use the path A? C? D? E for the transmission of messages to the node E. For this the source node A sends a message MES4, with the information DATA2 indicating that during its transmission a fault has occurred, and that it consists of the indication of the trajectory A? C? D? E. The node C after the evaluation of the message MES4 stores in the memory SC identifying information of its adjacent nodes along the path in the direction of the source node A, that is the source node A and its adjacent nodes along the path in the direction towards the target node E, this the node D, and transmits the message MES4 to the node D. in the memory SE and the source node A stores in the memory SA the identification information of the node C. Next the source node a can transmit messages to the target node E through the path A? C? D? E without indicating the path used. Although in FIG. 4 the path A? C? D? E was initialized first, after the source node A has received the error message ERROR from the path A? B? D? E, as shown in FIG. 5 it is also possible that the initialization of both trajectories A? C? D? E and A? B? D ?? parallel. Here the source node A transmits the message MES1 according to figure 1, including the message MES1 in addition to the information DATA1 and the data of the trajectory A? B? D? E also the data of the trajectory A? C? D? AND. In the memory SA of the source node A, two identification information for the adjacent nodes is stored in the direction of the target node, that is, the identification information of both nodes B and C. The storage of identification information in the SB and SC memories of nodes B and C is performed as described above. The node D, through which both trajectories A? B? D? E and A? C? D? E extend, it stores in the memory SD identification information on both paths of a different adjacent node, that is, nodes B and C. The source node A now after having performed the initialization of both paths A? B? D? E and A? C? D? E transmits messages selectively through one of the two paths A? B? D? E and A? C? D? E to the node E, directing the message to node B or node C. The decision about which The trajectory must be used, it may depend on criteria such as the length of the trajectory, the delay in time during the determination of the trajectory, the quality of transmission of trajectories or the age of the trajectories. When the decision on the trajectory used is taken by the source node, the message may include in the message, in addition to the data of the target node, information on which trajectory should be used for the transmission. However, it is also possible that a node which knows several nodes to transmit a message to a target node, makes a decision about the path to be used. The use of a plurality of trajectories according to FIG. 4 or 5 has the advantage that in the event that a transmission of a message can not be carried out completely through one of the paths, because the link between the two is interrupted. both adjacent nodes of the trajectory, another trajectory can be used. If, on the other hand, no other trajectory is available, then a new trajectory must be determined, and for the transmission of the route messages for the determination of the trajectory, transmission resources must be used. The invention saves transmission resources in two simple ways: by means of the possibility of using a plurality of trajectories the number of necessary route messages is reduced, which are used to determine the trajectory. By storing the adjacent nodes at each node, through which a path extends, during the transmission of messages through the path in question path data may be omitted, thereby avoiding redundant signaling information . If a node receives a message addressed to the target node from the source node through another node, which is not stored in memory as a node adjacent to the source node side, then that node can replace the stored node. In this way, it is guaranteed that the stored path can be used by the source node. This also has the advantage that the path can be modified without the source node being aware of the modification. Especially in radial symmetric networks, especially the nodes in the vicinity of the center, transmit many messages. Parts of a newly determined path of a source node in the direction of the center are also suitable for a path of another source node in the direction of the center. Therefore a node that has obtained the knowledge of a new trajectory towards the target node, for example in the case that during a transmission of messages along a new trajectory the node has stored in its memory the adjacent nodes in address of the target node, can transmit the messages of all the source nodes that are directed to that target node, through the new trajectory. This is advantageous since in this way current information about the trajectories can be used and the old trajectories can be updated. If a path is not used for a predetermined period of time, then the nodes can erase from their memories the identifying information of the adjacent nodes assigned to that path.

Claims (12)

1. NOVELTY OF THE INVENTION Having described the invention as above, property is claimed as contained in the following: CLAIMS 1. A procedure for transmitting information in a communication system with a plurality of nodes (A, B, C, D, E) , in which at least one or of the nodes (B, C, D) receives a message (MES1, MES4, MES4) that includes data from at least one path (A? B? D? E, A? C? D E) extending from when a source node (A) through at least one node (B, C, D) to another target node (E), the method is characterized in that at least one node (B, C, D) using the data from at least one path (A? B? D? E, A? C? D? E), stores identification information relating to both nodes (A, B, C, D, E) adjacent to when minus one node (B, C, D) along at least one path (A? B? D? E, A? C? D? E), and transmit the message (MES1, MES3, MES4) throughout of at least one trajectory (A? B? D? E, A? C? D? E). The method according to claim 1, characterized in that the message (MES1, MES3, MES4) that includes data from at least one path (A? B? D? E, A? C? D? E), is transmitted from the source node (A) of the at least one path (A? B? D? E, A? C? D? E). The method according to claim 1 or 2, characterized in that at least one other message (MES2), which does not contain data on the trajectory (A? B? D? E, A? C? D? E) that is going to used for transmitting at least one other message, it is transmitted from the source node (A) through at least one path (A? B? D? E, A? C? D? E) to the target node (E) using the identification information stored. The method according to claim 3, characterized in that after a failed transmission of the other message (MES2) from the source node (A) through at least one path (A? B? D? E, A? C ? D? E) to the target node (E), message that does not contain data about the path (A? B? D? E, A? C? D? E) used for the transmission, a message is transmitted (MES1, MES3 , MES4) that includes data from at least one path (A? B? D? E, A? C? D? E) from the source node (A) of the at least one path (A? B? D? E, A? C? D? E). The method according to one of claims 1 to 4, characterized in that a path (A? B? D? E, A? C? D? E) is determined with the collaboration of a device, which knows the relationships neighborhoods between the nodes (A, B, C, D, E) of the communication system. The method according to one of claims 1 to 5, characterized in that all the nodes (B, C, D) through which the at least one path extends (A? B? D? E, A? C? D? E), they receive the message (MES1, MES3, MES4) that includes the data of the at least one trajectory (A? B? D? E, A? C? D? E) and store identification information relating to the two nodes (A, B, C, D, E) adjacent to the nodes (B, C, D,) along the path (A? B? D? E, A? C? D? E). The method according to one of claims 1 to 6, characterized in that the at least one node (B, C, D) receives a message (MES1) that includes the data of several trajectories (A? B? D? E , A? C? D? E) that extend through at least one node (B, C, D) and stores the identification information of the two nodes (A, B, C, D, E) adjacent to the nodes (B, C, D,) along the path (A? B? D? E, A? C? D? E). The method according to one of claims 1 to 7, characterized in that the at least one node (D) after receiving the message from one of the nodes (B, C) sent from the source node (A) to the target node (E) through at least one path (A? B? D? E, A? C? D? E), with respect to which it has not stored identifying information about the adjacent nodes along when minus one path (A? B? D? E, A? C? D? E), stores identification information of that node (B, C) as of the adjacent nodes along at least one path (A? B ?FROM, A? C? D? E). . The method according to one of claims 8, characterized in that the at least one node (B, C, D) after receiving a data from another path between the at least one node (B, C, D) and the target node (E) which differs from at least one path (A? B? D? E, A? C? D? E), stores identification information of at least one node (B, C, D,) to along the node adjacent to the other path. 10. A node (B, C, D) in a communication system, in which the node (B, C, D) presents - means to receive a message (MES1, MES3, MES4) that includes data from at least one trajectory (A? B? D? E, A? C? D? E) that extends from a source node (A) to the target node (E) through the nodes (B, C, D), characterized in that the node (B, C, D) further presents - means for storing (SB, SC, SD) identification information of at least two nodes (A, B, C, D, E) adjacent to at least one node (B, C, D) along at least one trajectory (A? B? D? E, A? C? D? E) and means to transmit the message (MES1, MES3, MES4) along at least one path. { A? B? D? E, A? C? D? E). The node (B, C, D) according to claim 10, characterized in that the node (B, C, D) also has: - means for storing (SB, SC, SD) identification information of a node, which receives the message directed from the source node (A) to the target node (E) through at least one path (A? B? D? E, A? C? D? E), and with reference to which no has stored identification information of both an adjacent node along at least one path (A? B? D? E, A? C? D? E), and of an adjacent node along at least one path ( A? B? D? E, A? C? D? E). 12. The node (B, C, D) according to claim 10 or 11, characterized in that the node (B, C, D) also has: means for receiving a data of a second path between the nodes (B, C, D) and the target node (E) which is different from the at least one path (A? B? D? E, A? C? D? E), and - means to store (SB, SC, SD ) identification information of one node along the adjacent nodes in the other path.