Abstract:
Motor vehicles as well as infrastructure stations, which are stationary and which are installed on the side of the road such as traffic light systems for example, are provided as participants in a Car-to-X network. The vehicles include an automobile radio together with the communication unit for communicating with other participants of the network. In the event that such a vehicle travels through a region, for example a tunnel or a forest, in which a direct antenna reception of the radio signal of the radio station set in the automobile radio is poor or impossible and thus the reception quality of said radio signal is poor, the driver can be irritated or angered due to static or other disruptive noises as well as a loss of sound. Reception of radio signals in a Car-to-X communication system is improved by forwarding radio signals from one user to another.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is based on and hereby claims priority to International Application No. PCT/EP2012/003441 filed on Aug. 11, 2012 and German Application No. 10 2011 116 637.1 filed on Oct. 20, 2011, the contents of which are hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    The invention relates to a Car-2-X communications system, users in a Car-2-X communications system and a method for receiving radio signals in a Car-2-X communications system. 
         [0003]    In the related art, such systems, users and methods are known, for example, from the Car-2-X network, for which ETSI (short for “European Telecommunications Standards Institute”) is developing standards and specifications. This known network comprises both motor vehicles and infrastructure stations, which are stationary and, for example like traffic lights, are installed at the roadside. In addition to the communications unit for communicating with other users of the network, these vehicles also comprise a car radio. 
         [0004]    If such a vehicle is traveling through an area such as a tunnel or forest in which direct aerial-reception of the radio signal of the radio station set in the car radio is only poor or not possible at all, and hence the reception quality of this radio signal is poor, the driver may be distracted and irritated by noise and other interference and by loss of sound. 
       SUMMARY 
       [0005]    One possible object is to improve the reception of radio signals in a Car-2-X communications system. 
         [0006]    The inventors propose a Car-2-X communications system, a user in a Car-2-X communications system, a user in a Car-2-X communications system and a method for receiving radio signals in a Car-2-X communications system. 
         [0007]    According to a first aspect, the inventors propose a Car-2-X communications system comprising
       at least two users;   wherein   a first user comprises
           a first communications unit for receiving messages from the communications system and for sending messages into the communications system;   a first radio receiver for receiving radio signals;   
           a second user comprises
           a second communications unit for receiving messages from the communications system and for sending messages into the communications system;   a second radio receiver for receiving radio signals;   
           the first user further comprises
           a first control unit, which is coupled to the first communications unit and to the first radio receiver;   
           the first control unit is designed such that it
           monitors a first reception quality of a radio signal received by the first radio receiver;   if the first reception quality is less than a predetermined first threshold value, generates a request message requesting transmission of radio signals via the communications system, and sends by the first communications unit said request message into the communications system;   if the first communications unit receives from the second user an offer message, which contains a second reception quality of a radio signal received by the second user, on the basis of this offer message selects or does not select the second user as a partner;   if the second user is selected as a partner, generates a response message, which notifies a connection to the partner via the communications system for transmitting the radio signal received by the partner, and sends by the first communications unit said response message to the partner;   establishes the connection to the partner by the first communications unit;   routes the transmitted radio signal to the first radio receiver and instructs same to substitute this signal for the radio signal that it receives;   
           the second user further comprises
           a second control unit, which is coupled to the second communications unit and to the second radio receiver;   
           the second control unit is designed such that it
           monitors the second reception quality;   if the second communications unit receives from the first user the request message, and if the second reception quality is greater than or equal to a predetermined second threshold value, sends by the second communications unit the offer message to the first user;   if the second communications unit receives the response message, by the second communications unit establishes the connection to the first user and transmits the radio signal received by the second radio receiver to the first user.   
               
 
         [0031]    Since the transmitted radio signal received by the second radio receiver has a better reception quality than the radio signal received by the first radio receiver, the reception of radio signals in the Car-2-X communications system is improved. 
         [0032]    The first user can be, for example, one of the proposed users according to the second aspect of the proposals, and the second user can be, for example, one of the proposed users according to the third aspect of the proposals. 
         [0033]    Each of the control units can be designed in any way to suit requirements, for example in such a way that each control unit determines the particular reception quality at least on the basis of a signal strength of the particular radio signal that it is receiving. Alternatively or additionally, however, other criteria can also be used, for instance those used for the quality of service (QoS for short). 
         [0034]    The multi-hopping concept is preferably used, so that the second user sends by its communications unit the request message to further, third users of the communications system that lie outside the range of the first user, receives by its communications unit offer messages from such third users and sends said offer messages to the first user, sends by its communications unit response messages to such third users, and by its communications unit receives third radio signals, which are received by such third users, from such third users and sends said radio signals to the first user. 
         [0035]    The first control unit can be designed such that if the first reception quality is greater than or equal to the threshold value, the connection to the partner is cleared by the first communications unit. 
         [0036]    This removes the load from the communications system as soon as the transmission is no longer required or useful. 
         [0037]    The first control unit can be designed in any way to suit requirements, for example in such a way that it sets the first threshold value equal to the second reception quality. 
         [0038]    Thus, by comparing the first reception quality with the first threshold value, the first control unit can simultaneously compare the first reception quality with the second reception quality. 
         [0039]    Alternatively or additionally, the request message can contain the first reception quality. 
         [0040]    The second user can thus compare the first reception quality with the second reception quality and then generate or not generate the offer message according to the comparison result. 
         [0041]    The second control unit can be designed in any way to suit requirements, for example in such a way that if the request message contains the first reception quality, it sets the second threshold value equal to the first reception quality. 
         [0042]    By comparing the second reception quality with the second threshold value, the second control unit can thus simultaneously compare the first reception quality with the second reception quality and then respond appropriately according to the comparison result, for example by generating or not generating the offer message. 
         [0043]    Each radio receiver can be designed in any way to suit requirements, and, for example, can comprise a radio and/or a television and/or a mobile phone and/or a navigation unit. 
         [0044]    Each control unit can be designed in any way to suit requirements. For instance, it can be designed separately from the respective communications unit and/or the respective radio receiver or can be integrated in the respective communications unit and/or the respective radio receiver. 
         [0045]    The radio signals can be, for example, broadcast signals such as analog radio signals (FM, MW, LW) or digital radio signals (DAB, IBOC, SDARS) or analog or digital television signals or Traffic Message Channel signals (TMC), or mobile communications signals (telephony, SMS, Internet) or satellite navigation signals (GPS). 
         [0046]    The first control unit is preferably designed such that it adds to the request message information about the station or channel currently set in the first radio receiver. 
         [0047]    The second user can thus set in the second radio receiver of same this station or channel, or an alternative station or alternative channel assigned to this station or channel respectively, preferably using information about radio broadcasts provided by RDS. 
         [0048]    The second user can further comprise an additional radio receiver for receiving radio signals which is coupled to the second control unit, wherein
       the request message contains information about a channel required by the first user;   the second control unit is designed such that it
           sets the additional radio receiver to this channel or to an alternative channel assigned to this channel.   
               
 
         [0052]    Hence the second radio receiver can continue to work unchanged and, for example, play the radio station set by the driver, and use the additional radio receiver for the requested support for the first user. 
         [0053]    The second user can further comprise a navigation unit which is coupled to the second control unit, wherein
       the second control unit is designed such that it
           determines the current location of the second user by the navigation unit;   adds the current location to the offer message.   
               
 
         [0057]    The first user can thus compare its own current location with that of the second user and then respond appropriately according to the comparison result, for example by generating or not generating the response message. 
         [0058]    The first user can further comprise a navigation unit which is coupled to the first control unit, wherein
       the first control unit is designed such that it
           determines the current location of the first user by the navigation unit;   adds the current location to the request message.   
               
 
         [0062]    The second user can thus compare its own current location with that of the first user and then respond appropriately according to the comparison result, for example by generating or not generating the request message. 
         [0063]    According to a second aspect, the inventors propose a user in a Car-2-X communications system, in particular in one of the proposed Car-2-X communications systems, comprising
       a communications unit for receiving messages from the communications system and for sending messages into the communications system;   a radio receiver for receiving radio signals;   a control unit, which is coupled to the communications unit and to the radio receiver;       
 
         [0067]    wherein
       the control unit is designed such that it
           monitors a first reception quality of a radio signal received by the radio receiver;   if the first reception quality is less than a predetermined threshold value, generates a request message requesting transmission of radio signals via the communications system, and sends by the communications unit said request message into the communications system;   if the communications unit receives from another user of the communications system an offer message, which contains a second reception quality of a radio signal received by the other user, on the basis of this offer message selects or does not select the other user as a partner;   if a partner is selected, generates a response message, which notifies a connection to the partner via the communications system for transmitting the radio signal received by the partner, and sends by the communications unit said response message to the partner;   establishes the connection to the partner by the communications unit;   routes the transmitted radio signal to the radio receiver and instructs same to substitute this signal for the radio signal that it receives.   
               
 
         [0075]    The user can be, for example, the first user in one of the proposed Car-2-X communications systems according to the first aspect. 
         [0076]    The Car-2-X communications system can be, for example, one of the proposed Car-2-X communications systems according to the first aspect, and the other user can be, for example, one of the proposed users according to the third aspect. 
         [0077]    According to a third aspect, the inventors propose a user in a Car-2-X communications system, in particular in one of the proposed Car-2-X communications systems, comprising
       a communications unit for receiving messages from the communications system and for sending messages into the communications system;   a radio receiver for receiving radio signals;   characterized by   a control unit, which is coupled to the communications unit and to the radio receiver;   wherein   the control unit is designed such that it   monitors a reception quality of a radio signal received by the radio receiver;
           if the communications unit receives from another user of the communications system a request message requesting transmission of radio signals via the communications system, and if the reception quality is greater than or equal to a predetermined threshold value, sends by the communications unit an offer message containing the reception quality to the other user;   if the communications unit receives from the other user a response message, which notifies a connection to the other user via the communications system for transmitting the radio signal, establishes by the communications unit the connection to the other user and transmits the radio signal to the other user.   
               
 
         [0087]    The user can be, for example, the second user in one of the proposed Car-2-X communications systems according to the first aspect of the proposals. 
         [0088]    The Car-2-X communications system can be, for example, one of the proposed Car-2-X communications systems according to the first aspect of the proposals, and the other user can be, for example, one of the proposed users according to the second aspect of the proposals. 
         [0089]    The proposed users according to the second aspect and the proposed users according to the third aspect can be combined in any way to suit requirements, in particular combined in full or in part. 
         [0090]    According to a fourth aspect, the inventors propose a method for receiving or processing radio signals in a Car-2-X communications system, in particular in one of the proposed Car-2-X communications systems, wherein
       the communications system comprises at least two users;   a first reception quality of a first radio signal, which is received by a first user, is monitored;   a second reception quality of a second radio signal, which is received by a second user, is monitored;   if the first reception quality is less than a predetermined first threshold value, a request message requesting transmission of radio signals via the communications system is generated and is sent into the communications system;   if the request message is received and if the second reception quality is greater than or equal to a predetermined second threshold value, an offer message containing the second reception quality is sent to the first user;   if the offer message is received, the second user is selected or is not selected as a partner on the basis of this offer message;   if the second user is selected as a partner, a response message, which notifies a connection to the partner via the communications system for transmitting the second radio signal, is generated and sent to the partner;   the connection between the first user and the partner is established, and the second radio signal is transmitted to the first user;   in the first user, the transmitted second radio signal is substituted for the first radio signal.       
 
         [0100]    According to a fifth aspect, the inventors propose a method for receiving or processing radio signals in a Car-2-X communications system, in particular in one of the proposed Car-2-X communications systems, wherein
       the communications system comprises at least two users;   a first reception quality of a first radio signal, which is received by a first user, is monitored;   if the first reception quality is less than a predetermined threshold value, a request message requesting transmission of radio signals via the communications system is generated and is sent into the communications system;   if an offer message is received, which contains a second reception quality of a second radio signal received by a second user, on the basis of this offer message the second user is selected or is not selected as a partner;   if the second user is selected as a partner, a response message, which notifies a connection to the partner via the communications system for transmitting the second radio signal, is generated and sent to the partner;   the connection to the partner is established;   in the first user, the transmitted second radio signal is substituted for the first radio signal.       
 
         [0108]    According to a sixth aspect, the inventors propose a method for receiving or processing radio signals in a Car-2-X communications system, in particular in one of the proposed Car-2-X communications systems, wherein
       the communications system comprises at least two users;   a reception quality of a radio signal, which is received by a second user, is monitored;   if a request message requesting transmission of radio signals via the communications system is received from a first user, and if the reception quality is greater than or equal to a predetermined threshold value, an offer message containing the reception quality is sent to the first user;   if a response message, which notifies a connection to the first user via the communications system for transmitting the radio signal, is received by the first user, the connection to the first user is established and the radio signal is transmitted to the first user.       
 
         [0113]    The proposed methods according to the fifth and sixth aspect can be combined in any way to suit requirements, in particular combined in full or in part. 
         [0114]    For each of the proposed methods according to the fourth, fifth and sixth aspect, the Car-2-X communications system can be, for example, one of the proposed Car-2-X communications systems according to the first aspect, can be the first user, for example one of the proposed users according to the second aspect, and can be the second user, for example one of the proposed users according to the third aspect. 
         [0115]    Each of the users in one of the proposed Car-2-X communications systems according to the first aspect and in one of the proposed methods according to the fourth, fifth and sixth aspect, and each of the proposed users according to the second and third aspect, can be designed in any way to suit requirements, for example as a vehicle or as an infrastructure station. 
         [0116]    The embodiments relating to one of the aspects, in particular to individual features of this aspect, also apply correspondingly in a similar manner to the other aspects. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0117]    These and other objects and advantages of the present invention will become more apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which: 
           [0118]      FIG. 1  shows a vehicle in a first embodiment as a user in a Car-2-X communications system; 
           [0119]      FIG. 2  shows a vehicle in a second embodiment as a user in a Car-2-X communications system; and 
           [0120]      FIG. 3  shows a Car-2-X communications system in a preferred embodiment containing the vehicles of  FIG. 1  and  FIG. 2 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0121]    Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
         [0122]      FIG. 1  shows schematically a vehicle  10 . 1  as a first embodiment of a user  10 . 1  in a Car-2-X communications system  11  ( FIG. 3 ). This vehicle  10 . 1  is here in the form of a car and comprises a first communications unit  12 . 1  for receiving messages from the communications system  11  and for sending messages into the communications system  11 , a first radio receiver  13 . 1  for receiving first radio signals F 1 , and a first control unit  14 . 1 , which is coupled to the first communications unit  12 . 1  and to the first radio receiver  13 . 1 . 
         [0123]    In this first embodiment, the first radio receiver  13 . 1  is a car radio and hence the first radio signals F 1  are radio-station broadcasting signals. 
         [0124]    The first control unit  14 . 1  is designed such that it monitors a first reception quality of a first radio signal F 1  received by the first radio receiver  13 . 1 , such that, if the first reception quality is less than a predetermined first threshold value, it generates a request message A 1  requesting transmission of radio signals F 2  via the communications system  11 , and sends by the first communications unit  12 . 1  said request message into the communications system  11 , that, if the communications unit  12 . 1  receives from another user  10 . 2  ( FIG. 2  and  FIG. 3 ) of the communications system  11  an offer message B 2 , which contains a second reception quality of a radio signal F 2  received by the other user  10 . 2 , it selects or does not select the other user  10 . 2  as a partner on the basis of this offer message B 2 , that, if a partner  10 . 2  is selected, it generates a response message C 1 , which notifies a connection to the partner  10 . 2  via the communications system  11  for transmitting the radio signal F 2  received by the partner  10 . 2 , and sends by the first communications unit  12 . 1  said response message to the partner  10 . 2 , that it establishes the connection to the partner  10 . 2  by the first communications unit  12 . 1 , and that it routes the transmitted radio signal F 2  to the first radio receiver  13 . 1  and instructs same to substitute this transmitted radio signal F 2  for the radio signal F 1  that it receives. 
         [0125]    The first radio receiver  13 . 1  then feeds to an audio amplifier (not shown) the transmitted radio signal F 2  instead of the radio signal F 1  that it receives. 
         [0126]    In this first embodiment, the first control unit  14 . 1  is designed such that if the first reception quality is greater than or equal to the first threshold value, the connection to the partner  10 . 2  is cleared by the first communications unit  12 . 1 . 
         [0127]      FIG. 2  shows schematically a vehicle  10 . 2  as a second embodiment of a second user  10 . 2  in a Car-2-X communications system  11  ( FIG. 3 ). This second embodiment is similar to the first embodiment, and therefore only the differences are described in detail below. 
         [0128]    This vehicle  10 . 2  comprises a second communications unit  12 . 2  for receiving messages from the communications system  11  and for sending messages into the communications system  11 , a second radio receiver  13 . 2  for receiving second radio signals F 2 , and a second control unit  14 . 2 , which is coupled to the second communications unit  12 . 2  and to the second radio receiver  13 . 2 . 
         [0129]    In this second embodiment, the second radio receiver  13 . 2  is a car radio and hence the second radio signals F 2  are radio-station broadcasting signals. 
         [0130]    In this second embodiment, the second control unit  14 . 2  is designed such that it monitors a second reception quality of a second radio signal F 2  received by the second radio receiver  13 . 2 , that, if the second communications unit  12 . 2  receives the request message A 1  from the first vehicle  10 . 1  and if the second reception quality is greater than or equal to a predetermined second threshold value, sends by the second communications unit  12 . 2  the offer message B 2  to the first vehicle  10 . 1 , that, if the second communications unit  12 . 2  receives the response message C 1  from the first vehicle  10 . 1 , establishes by the second communications unit  12 . 2  the connection to the first vehicle  10 . 1  and transmits the second radio signal F 2  to the first vehicle  10 . 1 . 
         [0131]    This second embodiment is hence similar to the first embodiment, because the second communications unit  12 . 2 , the second radio receiver  13 . 2  and the second control unit  14 . 2  have a similar design to the first communications unit  12 . 1 , the first radio receiver  13 . 1  and the first control unit  14 . 1 . 
         [0132]    Hence the second control unit  14 . 2  is further designed such that, if the second reception quality is less than the second threshold value, it generates a request message A 2  requesting transmission of radio signals F 3  via the communications system  11 , and sends by the second communications unit  12 . 2  said request message into the communications system  11 , that, if the communications unit receives from another user of the communications system  11  an offer message B 3 , which contains a third reception quality of a radio signal F 3  received by the other user, it selects or does not select the other user as a partner on the basis of this offer message B 3 , that, if a partner is selected, it generates a response message C 2 , which notifies a connection to the partner via the communications system  11  for transmitting the radio signal F 3  received by the partner, and sends by the second communications unit  12 . 2  said response message to the partner, that it establishes the connection to the partner by the second communications unit  12 . 2 , and that it routes the transmitted radio signal F 3  to the second radio receiver  13 . 2  and instructs same to substitute this transmitted radio signal F 3  for the radio signal F 2  that it receives. 
         [0133]    Thus the second vehicle  10 . 2  can be used not only as a source for a requested better radio signal F 2 , for example requested by the first vehicle  10 . 1 , but can also itself, like the first vehicle  10 . 1 , request a better radio signal F 3  if necessary. 
         [0134]      FIG. 3  shows schematically a Car-2-X communications system  11  in a preferred embodiment. This communications system  11  comprises at least two users  10 , which are formed here by the users of  FIG. 1  and  FIG. 2 , or to be precise vehicles  10 . 1  and  10 . 2 . 
         [0135]    A proposed method for receiving radio signals F in a Car-2-X communications system  11  is described below with reference to this communications system  11 . 
         [0136]    The first user, or to be precise the first vehicle  10 . 1 , receives the first radio signal F 1  and monitors the first reception quality of the first radio signal F 1 . The second user, or to be precise the second vehicle  10 . 2 , receives the second radio signal F 2  and monitors the second reception quality of the second radio signal F 2 . Both radio signals F 1 , F 2  are sent by the same radio transmitter mast  15  on the same channel. The first vehicle  10 . 1  is currently driving through a forest  16 , which lies between the first vehicle  10 . 1  and the radio transmitter mast  15  and impairs direct aerial-reception of the first radio signal F 1 . The second vehicle  10 . 2  has already passed through the forest  16  and is currently driving on the same road in front of the first vehicle  10 . 1  through open countryside, and therefore there is no obstacle between the second vehicle  10 . 2  and the radio transmitter mast  15 , and direct aerial-reception of the second radio signal F 2  is not impaired. 
         [0137]    If the first reception quality is less than the first threshold value, the first vehicle  10 . 1  generates the request message A 1  and sends it into the communications system  11 . If the second vehicle  10 . 2  receives the request message A 1 , and if the second reception quality is greater than or equal to the second threshold value, it sends the offer message B 2  to the first vehicle  10 . 1 . If the first vehicle  10 . 1  receives the offer message B 2 , it selects or does not select the second vehicle  10 . 2  as a partner on the basis of this offer message B 2 . To do this, it compares the first reception quality with the second reception quality and selects the second vehicle  10 . 2  as a partner if the second reception quality is greater than the first reception quality. If the second vehicle  10 . 2  is selected as a partner, the first vehicle  10 . 1  generates the response message C 1  and sends same to the second vehicle  10 . 2 . As a result, the two vehicles  10 . 1 ,  10 . 2  establish the connection between one another, and the second vehicle  10 . 2  transmits via this connection the second radio signal F 2  to the first vehicle  10 . 1 . Then the first vehicle  10 . 1  substitutes the second radio signal F 2  transmitted in this way for the first radio signal F 1 . 
         [0138]    The invention has been described in detail with particular reference to preferred embodiments thereof and examples, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention covered by the claims which may include the phrase “at least one of A, B and C” as an alternative expression that means one or more of A, B and C may be used, contrary to the holding in  Superguide  v.  DIRECTV,  69 USPQ2d 1865 (Fed. Cir. 2004).