DE10233944B3 - Radio transmission method for mobile radio communications system with geocast-addressing has addressing of data effected via security layer of protocol structure - Google Patents

Abstract

The radio transmission method has the communication between 2 radio stations (A,B) linked via an air interface effected via hierarchy protocol layers, with implementation of an addressing method which uses geographic information. The addressing of data via an address containing at least one geographic information is effected via the security layer (DLL).

Description

The invention relates to a method for radio transmission of information in a mobile communication system with the Features of the preamble of claim 1.

In radio communication systems are Information (for example, language, image information, video information, SMS (Short Message Service) or other data) with the help of electromagnetic Waves over transmit a radio interface between transmitting and receiving radio station. The radiation of the electromagnetic waves takes place with Carrier frequencies, in the for the respective system provided frequency band lie.

In radio communication systems comes thereby made possible mobility the participant a big one Meaning too. In such systems, which for radio transmission used by information, several radio stations are over one Air interface connected to each other.

Location based services (location based services), will be in future Mobile radio systems play an increasingly important role. This location information can either by evaluating the intensity of received signals (Received Signal Strength, RSS) or by time differences (Time Of Arrival, TOA), or even with the help of satellite-based systems (Global Positioning System, GPS). obvious Applications for Location based services are e.g. paperless tourist guide (virtual tourist guides), path finder, advertising (advertisments), or emergency calls. Further fields of application, which Great for are location based services, are e.g. intelligent transport systems (ITS), which focus on radio communication between vehicles based, marketing along the road and Traffic information services.

For the addressing of subscriber stations in communication networks, In particular radio communication networks, various methods are known. In addition to the single sender (unicast), where a sender exactly another radio station addressed directly, is the Rundsenderuf (Broadcast), in which all radio stations within radio range of the transmitting station be addressed, most commonly represented. There is also the group broadcast (multicast), in which several Radio stations of a multicast group simultaneously with the broadcast of a multicast packet. Previously, every radio station, who wants to receive a multicast, join the multicast group for the sender to inform of a multicast packet is which radio stations the corresponding multicast message want to receive. A multicast, where all radio stations in the Range of a radio station are addressed, corresponds to one Broadcast.

With the introduction of the Internet Protocol IPv6 the addressing type Anycast has been added, similar to a Broadcast all radio stations are potentially addressed. however decides the recipient, whether the package for he was destined. If this is given, he can answer it. The Sender does not need to know who the recipient of the Instead, she sends the message "on suspicion" to all radio stations first radio station which fulfills the criteria of a receiver can answer the sending station.

In addition to the mentioned addressing method The geocast is of great importance recently, in particular regarding its use in ad hoc networks. Under an ad hoc network one understands a wireless communication net, which usually without existing infrastructure such as Operated base stations becomes. In contrast to other mobile networks this traffic is over one or multiple nodes routed to the destination. The geocast addressing method but is also used in other mobile communication systems. Geocasting is an addressing method in which one or more radio stations not exclusively using their unique ones Addresses but with the help of geographic information addressed become. The Geocast is thus a variant of the conventional one Multicast, where the group which is addressed as the recipient, by geographical information is determined. Based on this addressing type are routing methods, i. Method for selection, proposed.

The OSI Reference Model (OSI: Open System Interconnection) of the International Standardization Organization ISO was used as the basis for the Education of communication standards designed. It shares the network communication in seven layers, each layer having a different job Fulfills. The communication between the participants, e.g. the radio stations, is done over hierarchical protocol layers. The communication between the different levels of the model takes place in the vertical direction instead of, i. to be transferred Data is passed from layer to layer. It puts every layer of it above lying layer at so-called service access points (Service Access Points, SAPs) services available. A service access point generally designates the determining logical Interface between adjacent layers in the OSI reference model, where a parent Layer can access the services of the child.

The first (lowest) layer is It is the physical layer or physical layer. It defines the communication technology tools for transmission.

The following second layer, the data link layer contains sequences of binary information to data packets together or solves larger units, those from a higher layer come, if necessary, into smaller data packages. In addition will some redundancy in the form of control information of the to be transmitted Data inserted in the data packets. Another task of the backup layer is the media access control (MAC: Media Access Control). The task of the MAC sublayer is to coordinate access to the common medium. For transmission the data on the individual sections, the MAC address is used here.

The most important task of the third Layer, the switch or network layer is the one Routing, i. the determination of an optimal path through a branched one Network. In this layer, the addressing of the data for the end-to-end takes place Connection with the network layer address instead.

The addressing methods described above are supported on the network layer, which also includes routing is realized.

The geocast addressing method has been as follows so far realized: combined with routing methods on the network layer it is used under the name "geographical routing" are next to the unique address of the subscriber stations also exchanged their geographical coordinates. Based on the position information the addressee becomes a packet from one radio station to the next radio station forwarded until it reaches the destination station. This will not be Route over various radio stations in the strict sense built over the the package is transmitted becomes. Rather, relay stations are on the way to the destination station chosen spontaneously, depending on which radio station is currently positioned most favorably. The relay stations are not over her address selected, but about her Position.

In 1 shows how the addressing type Geocast is implemented on the network layer and the link layer. The radio station A acts here as the transmitter, the radio station B as the recipient of the geocast message. Both radio stations are structured according to the OSI reference model described in the physical layer PL (Physical Layer), the data link layer DL (Data Link Layer), the network layer NL (Network Layer) and the higher layers HLs (Higher Layers). The two in 1 drawn service access points SAP are characterized by the relevant service they offer: the broadcast and the unicast addressing ("broadcast" and "unicast").

The geocast is on the network layer NL realized using a geographical address. The Netzschicht NL thus has the information in which direction the Data should be forwarded. On the link layer DLL the geocast is realized as unicast. That is, there is an address filtering of the data on the link layer DLL instead, here is the MAC address Station chosen, which acts as a forwarding station. This requires the network layer NL know the current positions of neighboring stations and their MAC address. Then could the network layer NL already carry out a preprocessing of the data and transmit the geocast directly as unicast. The physical transmission The data is from the physical layer PL in the form of a broadcast carried out.

However, if the topology changes fast and the last update of the assignment of address and position is too long in the past, the unicast is outdated Information realized and then missed his goal. In the worst case Case then the packet is transmitted in the opposite direction. In these cases is a broadcast preferable to unicast, with only the current Position of the receiver over the appropriate forwarding station decides. That is, it does not find any Address filtering of the data at the data link layer DLL instead, here is called MAC address used a broadcast address. Filtering then takes place receiver B on the network layer NL based on the geographical address.

By the way of the 1 explained methods for realizing a geocast by a broadcast on the link layer DLL are all disadvantages that has a broadcast over the multicast or the unicast, transferred to the geocast. In particular, it should be noted here that all potential recipients of the Geocast must be ready to receive, which has a negative effect on the power consumption and thus shortens the standby time. Furthermore, it is disadvantageous that a reliable transmission by the link layer DLL can hardly be ensured in the described Geocast method, so that overall the efficiency of addressing or overhead is suboptimal.

Will the geocast be on the link layer dll realized as unicast the information of the neighboring stations in the form of position and address constantly to be updated. This additional Signaling overhead can be significant, especially in highly mobile networks his. Moreover, it can not be ruled out that stations that supposedly are achievable due to rapidly changing radio propagation conditions (Multipath propagation and / or shadowing and / or interference) are no longer available. Thus, even with correct position and unicast address information unsuccessful.

The invention is therefore the task underlying a method of the type mentioned, which implements a geocast in a more efficient way.

This task is performed by the procedure solved with the features of claim 1. Advantageous embodiments and further developments are the subject of dependent claims.

In the method according to the invention is an addressing of data by means of at least one geographical Information containing address performed on the link layer.

In the invention reference is made on the link layer and also on the network layer with regard to on the functions that the eponymous layers in the ISO / OSI Take reference model. A description of these functions can be found e.g. in B. Walke: Mobile networks and their protocols, Volume 1, 2. Edition, 2000, Teubner GmbH, pp. 64-68. It should be emphasized, however that will not be the name of each layer relevant is, but its essential function. The inventive method is not limited on communication systems, which are structured according to the ISO / OSI reference model are. Rather, it is also applicable to communication systems, their "link layer" and "network layer" - in quotes because the layers may have a different name - not all functions according to the ISO / OSI reference model but only a subset of these functions. Also can functions in the Added to the ISO / OSI reference model. critical for the Applicability of the method according to the invention on these systems is that the "link layer", ie the layer, which includes the characterizing part of claim 1, under the layer whose function is the end-to-end addressing is ("network layer").

A significant advantage of the method according to the invention is that due to the reduced on the data link layer receiver circuit a reliable transmission ensured by the link layer can be. The resulting signaling effort is compared to the usual Geocast reduced. This is especially the case when the geographical target region is significantly smaller than that region which receives the broadcast.

Because only those radio stations data receive who are in the geographical target area, can standby time through power savings in those Radio stations increased who are not in the geographical target area. This is particularly important in ad hoc networks.

Furthermore, there is the advantage dynamic topologies in that new neighbor stations, the Sender station were previously unknown, used as a receiver can be. Thus, without tedious and overhead producing signaling a data transfer be realized between radio stations in radio range. Self if the MAC addresses of the neighbors are not known, the Data is purposefully and quickly forwarded. It is thus for this service neither the knowledge of the MAC address nor the position of the recipient the backup layer necessary.

In a further development of the invention the at least one geographical information containing address on the link layer as the only address on this layer or additionally used to another address without geographic information. The latter addresses may be the traditional MAC addresses (e.g., MAC broadcast, MAC unicast, etc.). Replaces the geographical information containing address on the link layer the MAC address, so Therefore, one can speak of a new type of MAC address: the MAC Geocast address.

Preferably, the addressing becomes of data by means of the at least one geographical information address on the link layer into the media access controller Realized (Medium Access Control, MAC) provided data elements.

In one embodiment of the invention requests the network layer from the link layer as a service geographically directed transmission in which as parameters pass the geographical information becomes.

The geographical information which is used for addressing on the link layer Location coordinates of addressees and / or angle information and / or Radius information and / or angle ranges related to a reference coordinate system. The position of a recipient can therefore e.g. be determined by direction and radius, it is but also the specification of an angle range for addressing all Radio stations in this area possible. Location coordinates may e.g. be provided with GPS assistance on the network layer.

The geographic location used on the link layer Address preferably agrees with at least one geographic information containing address, which for the corresponding transmission also on the network layer used to match. This has the advantage that the overhead volume is kept low.

In a further development of the invention, the geographical address used on the data link layer is an address specific to the data link layer which does not coincide with those geographical information-containing addresses in the network layer for the relevant transmission. Only the addressed area or the area agrees exactly or largely. As a result, the strict layer construction of the communication system may be maintained according to the ISO / OSI reference model, if necessary. It is also possible to depend on the type of geographical addresses used on the data link layer for the time, for the various transmissions or for the various radio stations.

In a preferred embodiment The invention is an ARQ (Automatic Repeat Request) method used. This increases the reliability of the transmission clear. Especially if data is forwarded via several radio stations, it is advantageous to get a guarantee that the data from the relay stations were actually transmitted. To realize there there are different ways: the procedure can either over positive acknowledgments (Acknowledgment, ACK) or over negative acknowledgments (Negative Acknowledgment, NAK) work.

Details and details of the invention are based on an embodiment explained below. Show

1 Protocol structure for a radio communication with geocast addressing according to the prior art,

2 Protocol structure for a radio communication with geocast addressing according to the invention.

1 relates to a radio transmission using a geocast addressing method between two radio stations, as stated above.

2 shows two radio stations A and B characterized by their layer structure with the physical layer PL, the link layer DLL, the network layer NL and the higher layers HLs. 1 and 2 have some similarities, such as the basic structure of the protocol layers. Therefore, the focus here will be on the differences. Data is to be transferred from A to B using the Geocast method of the invention. Since the link layer supports this type of addressing, see 2 In addition to the already known service access points for the other addressing methods, in contrast to the conventional realization of the geocast, such as, for example, in US Pat 1 shown - corresponds to the logical connection between the backup layers DLL of the two radio stations A and B a geocast. In other words, in the receiver station B on the link layer DLL, filtering is performed on the link layer specific geographic address, and thus only the filtered data is passed to the network layer NL.

As an application of the method the possibility, at a geocast several radio stations in one area at the same time to address. These radio stations must generally be common geographic information be describable. Except one common region, this can also be a common angle sector, that is, the addressed radio stations can be very different far from the receiver are located away. This is e.g. then of interest, if vehicles on the highway above to be informed that there is a traffic jam in front of them. In In this case, all vehicles against the direction of travel through informed a stowage participant. Make this geocast efficient can be forwarded, the geocast is on the link layer also realized as Geocast, whereby by announcement of the radio destination station the corresponding radio station are ready to receive.

In addition, in combination with sector antennas or adaptive antennas, the transmission power can be radiated directionally. This has the great advantage of reducing unwanted interference compared to broadcasting. The inventive method facilitates the implementation of the directional radiation through the antennas thereby; that more efficient control of the physical layer antennas is made possible by using the geographic address of the link layer. So there is a direct Interak tion between the MAC layer (second layer) and the antenna control (first layer) instead. Furthermore, so targeted sectors can be controlled with different directions. For example, a message for vehicle-to-vehicle communication could be transmitted forward and at the same time back along a road. Another embodiment relates to the medium access method. By geographic addressing on the link layer, a receiving station can compute a spatial relationship between the geographical information currently characterizing it and the geographical information contained in the destination address. In terms of location coordinates, this could mean determining how close the receiver station is to the desired geographic target location. For this purpose, a determination of the distance between their current geographical position and the target position takes place. The closer this radio station is to the destination position, the sooner it should notify the sender of a positive acknowledgment that it has received the data and passed it on to its network layer. If the radio stations are addressed, for example, over an angular range in a coordinate system, then the receiver station should send back the fastest a positive reception acknowledgment, which is at white test away from the transmitter station and placed closest to the bisecting line. Corresponding algorithms can be used to determine the spatial relations.

Claims (11)

Method for the radio transmission of information in a mobile radio communication system consisting of at least two radio stations which are connected via an air interface, wherein the communication takes place via hierarchical protocol layers and wherein an addressing method using geographic information is used, characterized in that an addressing of data by means of at least one geographic information containing address on the data link layer (DLL) is performed. Method according to claim 1, characterized in that that the at least one geographical information containing address on the link layer (DLL) as the only address on this layer or additionally to an address without geographical information is used. Method according to one of claims 1 to 2, characterized that the addressing of data by means of at least one geographical information address on the link layer (DLL) into the media access controller provided data elements is realized. Method according to one of claims 1 to 3, characterized the network layer (NL) serves as a service for a geographically directed transmission of the link layer (DLL) requests, where as a parameter the geographical Information is passed. Method according to one of claims 1 to 4, characterized that the geographical information is location coordinates and / or angles and / or radii and / or angular ranges relative to a reference coordinate system includes. Method according to one of claims 1 to 5, characterized that the at least one geographical information containing address on the link layer (DLL) with at least one geographical Information containing address on the network layer (NL) at the same transmission. Method according to one of claims 1 to 5, characterized that the at least one geographical information containing address on the link layer (DLL) differ from the at least one geographic one Information containing address on the network layer (NL) at the same transmission different. Method according to one of claims 1 to 7, characterized that an ARQ (Automatic Repeat Request) method is used. Method according to one of claims 1 to 8, characterized that several radio stations whose geographical positions are due common geographical information is describable, at the same time be addressed by a radio station. Method according to one of claims 1 to 9, characterized that sector and / or adaptive antennas are used. Method according to one of claims 1 to 10, characterized that in at least one radio station, a spatial Rela tion between the this at least one radio station currently characterizing geographic Information and containing in the at least one geographical information Address used geographic information is performed.