Patent Publication Number: US-6707378-B2

Title: Inter-vehicle wireless communication and warning system

Description:
BACKGROUND OF INVENTION 
     The present invention relates generally to vehicle communication systems, and more particularly, to a method and apparatus for communicating between multiple vehicles in a close proximity of each other. 
     Collision countermeasure and warning systems are becoming more widely used. Collision countermeasure and warning systems detect objects or vehicles within close proximity of a host vehicle and perform safety operations so as to prevent or minimize the likelihood of a collision and any resulting injury to an occupant. 
     In the development of collision countermeasure and warning systems vehicle-to-vehicle communications has been suggested for increased host vehicle awareness of other vehicles or potentially hazardous conditions that may exist within a close proximity to the host vehicle. 
     Vehicle-to-vehicle communication for safety purposes requires several distinct types of data communication. A host vehicle should be aware of vehicles that may be approaching from multiple directions and at various velocities. A host vehicle should also be aware of various traffic conditions, such as a slow moving congested traffic situation versus a clear faster moving situation when a first vehicle may pass a second vehicle. Thus, a host vehicle in motion must be able to discover and communicate with additional vehicles that are traveling in a concurrent manner, including vehicles approaching from a forward, rearward, or lateral direction of a host vehicle. 
     Traditional vehicle communication systems have a vehicle time delay discovery problem. The faster the vehicles are moving the more significant the time delay becomes. Traditional vehicle communication systems operate sufficiently in discovering vehicles in a close proximity under slow moving traffic conditions. Generally, during a slow moving traffic condition vehicles tend to remain in host vehicle range for a reasonable amount of time, allowing the host vehicle to discover the vehicles without any timing issues. The timing issues become more evident when a vehicle is approaching in a lateral direction, and are a particular concern for vehicles approaching from the forward or rearward directions. Vehicles approaching from the forward or rearward directions, such as during a passing situation, must be discovered at a relatively large distance from the host vehicle. Large time delays must be overcome in discovery of a passing vehicle as compared with time that is actually required to pass a vehicle, which is short. 
     The lateral approaching vehicle situation introduces an additional problem with existing vehicle communication systems. Objects between the host vehicle and the approaching vehicle may block communication signals and make detecting laterally approaching vehicles difficult. Thus, network communication is crucial to provide advanced warning of objects or potential hazards to vehicles within the network. 
     Ad hoc wireless mobile networks are commonly used because of their associated desirable benefits for vehicle-to-vehicle data communication including: lack of reliance on third party infrastructures, ability to adapt to local conditions readily, ability to allocate resources on a local level, and absence of single points of failure. Also, commodity implementations of ad hoc networking hardware are readily available and well proven. However, ad hoc wireless mobile networks have disadvantages associated with routing of communication signals. 
     Traditional networks differ from wireless mobile networks in that the network devices are connected in contained network spaces in which each device has equal access to the other devices, and communicate through a single network device to access another network space. Furthermore, in traditional networks, the addressing of individual devices is abstracted from the geographical relationship between devices. Ad hoc wireless mobile network devices, however, do not have contained network spaces or equal access to other devices. Additionally, connection between devices is very location dependent because wireless network devices have finite range. 
     Vehicle-to-vehicle network devices are constantly moving in and out of range and topology of the network is constantly changing. The density of the network is also constantly changing. Therefore, traditional dynamic network routing concepts, in which devices are discovered on the network and routes between devices are calculated and stored, are difficult to apply. 
     Referring now to FIG. 1, a vehicle communication signal pattern diagram  10  for multiple vehicles  12  in a tight cluster situation using ad hoc vehicle communication and omni-directional antennas, is shown. Arbitration is easily handled between the omni-directional antennas using collision detection and recovery or time domain multiplexing approaches. Each vehicle is able to communicate with every other vehicle in the tight cluster due to overlapping of each vehicle transmission range  14 . 
     Referring now to FIG. 2, a vehicle communication signal pattern diagram  16  for multiple vehicles  18  in a spread out cluster situation using ad hoc vehicle communication and omni-directional antennas, is shown. When a cluster of vehicles  20  is spread out enough that not all vehicles are in communication range of each other, then handshaking mechanisms are required. The handshaking mechanisms can become congested. As an illustrative example, vehicle A may transmit a request to send (RTS) to vehicle B, vehicle B then responds with a clear to send (CTS) to vehicle A. Since vehicle C is in range of vehicle B, vehicle C must wait to respond to a RTS from vehicle D so as not to conflict with vehicle A″s transmission to vehicle B. Vehicle E sends a RTS to vehicle D, but vehicle D is waiting for vehicle C″s CTS and vehicle C is waiting for vehicle A and vehicle B to finish communicating. The handshaking methods are less efficient than collision detection approaches, as in the tight cluster situation, and can lead to network gridlock under certain conditions. 
     It would therefore be desirable to develop a wireless mobile communication network for vehicle-to-vehicle communication that is feasible to implement for various approaching vehicle situations, that overcomes the above mentioned timing issues, and that is cost effective. 
     SUMMARY OF INVENTION 
     The present invention provides a method and apparatus for communicating between multiple vehicles in close proximity to each other. An inter-vehicle wireless communication and warning system for a host vehicle within a wireless communication network is provided. The system includes a first variable antenna that receives a vehicle discovery signal and a variable amplifier that is electrically coupled to the first variable antenna, which modifies the vehicle discovery signal. A smart transmission antenna focuses and transmits a pattern signal to at least another vehicle in the wireless communication network. A smart antenna amplifier is electrically coupled to the smart antenna and modifies the pattern signal. A main controller is electrically coupled to the variable amplifier, the smart antenna amplifier, and a vehicle network. The main controller generates the pattern signal in response to the vehicle discovery signal and a vehicle network signal. 
     One of several advantages of the present invention is the incorporation of smart antennas and smart antenna control into an inter-vehicle communication system. In so doing, a vehicle-communication pattern may be adjusted to meet a particular communication requirement. Additionally, the smart antennas allow for quick switching between patterns. 
     Another advantage of the present invention is the synchronization of a global clock signal and vehicle communication patterns, thereby, minimizing interference between neighboring transceivers and allowing concurrent vehicle communication involving several patterns that are not interfering with each other. 
     Furthermore, the present invention utilizes multiple vehicle technologies that are widely available to minimize additional costs to a vehicle system. 
     Other advantages and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a vehicle communication signal pattern diagram for multiple vehicles in a tight cluster situation using ad hoc vehicle communication and omni-directional antennas; 
     FIG. 2 is a vehicle communication signal pattern diagram for multiple vehicles in a spread out cluster situation using ad hoc vehicle communication and omni-directional antennas; 
     FIG. 3 is a block diagrammatic view of an inter-vehicle wireless communication and warning system in accordance with an embodiment of the present invention; 
     FIG. 4 is a pattern signal diagram for a host vehicle in accordance with an embodiment of the present invention; 
     FIG. 5 is a skewed pattern diagram of a transmitted pattern signal in accordance with an embodiment of the present invention; 
     FIG. 6A is a vehicle communication signal pattern diagram for multiple vehicles in a spread out cluster situation, communicating in a forward direction, using the inter-vehicle wireless communication and warning system and ad hoc vehicle communication in accordance with an embodiment of the present invention; 
     FIG. 6B is a vehicle communication signal pattern diagram for multiple vehicles in a spread out cluster situation, communicating in a rearward direction, using the inter-vehicle wireless communication and warning system and ad hoc vehicle communication in accordance with an embodiment of the present invention; 
     FIG. 7 is a logic flow diagram illustrating a method of communicating between a plurality of vehicles within a close proximity of each other in accordance with an embodiment of the present invention; and 
     FIG. 8 is a sample network topology diagram in accordance with an embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION 
     In each of the following figures, the same reference numerals are used to refer to the same components. While the present invention is described with respect to a method and apparatus for communicating between multiple vehicles in a close proximity of each other, the present invention may be adapted to be used in various systems including: automotive vehicle systems, control systems, communication systems, or other systems that may utilize a smart antenna or the like. 
     In the following description, various operating parameters and components are described for one constructed embodiment. These specific parameters and components are included as examples and are not meant to be limiting. 
     Referring now to FIG. 3, a block diagrammatic view of an inter-vehicle wireless communication and warning system  50  for a host vehicle  52  in accordance with an embodiment of the present invention, is shown. The system  50  includes a first variable antenna  54  electrically coupled to a variable amplifier  56 , which is electrically coupled to a main controller  58 . The variable amplifier  56  is a low gain amplifier that modifies vehicle discovery signals received from the first variable antenna  54 . The main controller  58  is also electrically coupled to a vehicle network  60 , which generates a network signal. The vehicle discovery signals and the network signal may include vehicle proximity information relative to the host vehicle  52 . The main controller  58  combines vehicle information received from the first variable antenna  54  and the vehicle network  60 , and through the use of ad hoc communication, generates and transmits a pattern signal via a smart antenna  62  having multiple elements  64 . The pattern signal is modified by a smart antenna amplifier  66  and is focused and transmitted by the smart antenna  62  to multiple vehicles in close proximity of the host vehicle  52 . A vehicle direction prediction device  67  is electrically coupled to the main controller  58  and contains a global positioning system  68  that aids in timing of communication signals and in vehicle location determination. The global positioning system  68  receives timing and vehicle data via a second variable antenna  70  and generates a global positioning signal that is utilized by the main controller  58  in generating the pattern signal. 
     The main controller  58  comprises a wireless network communication device  72 , a network controller  74 , and a smart antenna controller  76 . The main controller  58  is preferably microprocessor-based such as a computer having a central processing unit, memory (RAM and/or ROM), and associated input and output buses. The main controller  58 , the communication device  72 , the network controller  74 , and the smart antenna controller  76  may be a portion of a central control unit or may each be stand-alone components. The main controller  58  adjusts characteristics of the pattern signal such as size, shape, strength, and pattern center. 
     The vehicle network  60  may be an internal or external vehicle network. The main controller  58  may be electrically coupled to the vehicle network  60  via a personal computer memory card international association (PCMCIA) port, a cardbus, a miniature card, an instrumentation, systems, and automation society (ISA) bus, a peripheral component interface (PCI) bus, or other port, bus, or card known in the art. The vehicle network  60  may contain a central computer or storage center for vehicle network information contained within the network signals. 
     The communication device  72  facilitates communication between vehicles. The communication device  72  may be a bluetooth device, a local area network (LAN) 802.11 system, or a LAN 802.11b system, a digital short range communication device, an ultra wide band communication device, a wireless network radio, or other wireless communication device that is able to receive and transmit modulated radio frequency signals. 
     The network controller  74  controls routing of various information between vehicle electronic devices including: the communication device  72 , the smart antenna controller  76 , the global positioning system  68 , and other possible vehicle components not shown such as a navigation system, object detection sensors, countermeasure systems, or other vehicle electronic devices and components. The network controller  74  is electrically coupled to the variable amplifier  56  and may adjust the gain of the amplifier  56 . 
     The network controller  74  also generates the pattern signal  78 . The pattern signal  78  may comprise multiple patterns  80 , as best seen in FIG.  4 . Each pattern  80  is associated with vehicle information directed to an adjacent vehicle  82  in close proximity with the host vehicle  52 . The pattern signal  78  may, contain vehicle communication information pertaining to multiple vehicles including the host vehicle or may serve as a type of beacon transmitting host vehicle information so as to alert other vehicles in or approaching the host vehicle  52 . The pattern signal  78  may be omni-directional, uni-directional, or multi-directional. In other words, the pattern signal may be transmitted equally in all directions, primarily in a single direction, or in multiple predetermined directions depending upon the situation. The pattern signal is generally received and upon reception transmitted without altering data content of the pattern signal. 
     The smart antenna controller  76  adjusts the amplitude, timing, orientation, skewing, and shape of the pattern signal by adjusting electrical characteristics associated with the smart antenna  62 . For example, the smart antenna controller  76  may focus transmission power of the smart antenna  62  in a forward direction leaving little power for transmission in a rearward direction, as best seen in FIG.  5  and represented by patterns  84  and  86 , respectively. The smart antenna controller  76  in order to focus the transmission power delays signal transmission to certain elements within the smart antenna  62 , in turn adjusting the phase of the communication signal being transmitted by the selected elements. 
     The smart antenna  62  consists of the phase array of antenna elements  64  in a patch of film with each element electrically coupled to a solid-state delay device and a variable amplifier. The variable amplifier represented by smart antenna amplifier  66 . Smart antenna  62  may incorporate the first variable antenna  54  and the second variable antenna  70  into a single smart antenna. Smart antennas in general are able to switch between signal patterns in milliseconds, which is much faster than the time duration of typical traffic events or collisions. Therefore, several pattern signals may operate concurrently without interfering with each other. 
     Time domain of the main controller  58  is divided into periods, in each period at least one specific function is performed. Vehicles utilizing system  50 , which are in close proximity with each other, are synchronized dynamically in order to perform the specific functions in an appropriate sequential order. The specific functions may include: inquiry and discovery of vehicle related data, transmitting and receiving data to and from a vehicle forward of or behind the host vehicle  52 , or transmitting and receiving data to vehicles that are to the left or to the right of the host vehicle  52 . The time domain may be synchronized through the use of the GPS system  68 , or by other methods known in the art. 
     Referring now to FIGS. 6A and 6B, vehicle communication signal pattern diagrams  90  for multiple vehicles  92  in a spread out cluster situation, is shown. Each vehicle  92  is using the inter-vehicle wireless communication and warning system  50  and ad hoc vehicle communication in accordance with an embodiment of the present invention. The signal patterns  94  using smart antennas may be directed toward a communication vehicle of interest in a cluster of vehicles. The smart antenna pattern signals may be adjusted in size, shape, and pattern signal center to meet a particular communication requirement. 
     The combination of smart antennas and global positioning systems in multiple vehicles allows for more effective arbitration of communication between vehicles. For example, instead of using request to send and clear to send commands and various handshaking protocols, synchronized communication between the vehicles  92  may occur. In a first time interval, messages may be transmitted in a forward direction from vehicle A to vehicle B, followed by vehicle B transmitting messages to vehicle C, followed by vehicle C transmitting messages to vehicle D, and finally vehicle D transmitting messages to vehicle E. In a second time interval, messages may be transmitted in a rearward direction, from vehicle E to vehicle D, from vehicle D to vehicle C, from vehicle C to vehicle B, and finally from vehicle B to vehicle A. By synchronizing transceivers in multiple vehicles by a global clock signal from the global positioning units, pattern signals may be altered in unison, reducing interference between transceivers in close proximity. 
     Referring now to FIG. 7, a logic flow diagram illustrating a method of communicating between a plurality of vehicles within close proximity of each other in accordance with an embodiment of the present invention, is shown. 
     In step  100 , the first variable antenna  54  receives a vehicle discovery signal from a vehicle in close proximity to the host vehicle  52 . The vehicle discovery signal may be in the form of a pattern signal or other vehicle-to-vehicle communication signal. The vehicle discovery signal, similar to a pattern signal, may include vehicle information relative to the host vehicle  52  such as vehicle traveling velocity, vehicle distance, vehicle location, or other vehicle information known in the art. The vehicle information may pertain to the host vehicle  52  or one or more vehicles in close proximity to the host vehicle  52 . 
     In step  102 , the variable amplifier  56  amplifies or attenuates the vehicle discovery signal depending upon the vehicle situation. When the host vehicle  52  is in a congested traffic situation the received vehicle discovery signal may be attenuated as opposed to when the host vehicle  52  is operating on an open road where few or no vehicles are near the host vehicle  52 . The communication device  72  may block a received vehicle discovery signal in response to a vehicle discovery signal characteristic such as power. For example, when a received vehicle discovery signal is below a predetermined power level the corresponding vehicle that transmitted the vehicle discovery signal is not in close proximity with the host vehicle  52  and the communication device  72  ignores the received vehicle discovery signal. Blocking of certain received signals aids in minimizing interference between vehicle pattern signals. 
     In step  104 , the communication device determines and stores one or more vehicle proximity parameters relative to the host vehicle  52  in response to the vehicle discovery signal and the vehicle network signal to generate a vehicle proximity signal. The proximity signal may contain vehicle locations, vehicle velocities, vehicle distances, or other vehicle characteristic information relative to the host vehicle  52 . The communication device  72  may generate in conjunction with or in replacement of the vehicle proximity signal, a vehicle mapping proximity signal in response to a mapping signal generated by the network controller  74 , in step  110 . 
     In step  106 , the global positioning system  68  receives a global positioning signal via the second omni-directional antenna  70 . The global positioning signal may include a global clock signal and mapping information. The global clock signal is used to synchronize communication between multiple vehicles in a close proximity. The global clock signal is received by each vehicle, in a cluster of vehicles, simultaneously. Each vehicle sets a respective internal clock to match the global clock signal. The network controller  74  may alternate between the received discovery signal and the pattern signal in response to the global clock signal. 
     Upon synchronization the smart antenna controller  76  may set the smart antenna  62  and the smart antenna amplifier  66  to transmit a certain pattern signal. The certain pattern signal may contain data received from the network signal and is transmitted for a predetermined time frame and for a specific function. The main controller  58  may utilize the global clock signal when dictating the timing sequence for performing the specific functions. 
     Since vehicles, utilizing system  50 , are able to transmit and receive communication signals in multiple directions simultaneously, and switch directions quickly, a network topology  108  may be defined and mapped into a grid  110 , as best seen in FIG.  8 . The mapping information includes vehicle location information associated to the grid  110 . By using smart antennas to skew signal patterns and adjust amplitude and system sensitivities such that only desired adjacent vehicles communicate, the grid is conformal. That is, the network topology may be mapped onto a grid of polygons  112  that all have the same dimension. The use of a network topology prevents network congestion and simplifies routing of communication signals. 
     Referring again to FIG. 7, in step  114 , the network controller  74  generates a scheduling signal and a pattern signal in response to a vehicle network signal and the global positioning signal. The scheduling signal includes scheduling information for the smart antenna patterns, which is used in synchronizing transmission and reception with the patterns. The vehicle network signal may be generated from a host vehicle object detection sensor, a navigation system, or other vehicle electronic device. The network controller  74  may also generate a mapping signal in response to the global positioning signal. The mapping signal contains vehicle location information corresponding to a polygon  112 . 
     The pattern signal may be generated in response to a prediction signal from the prediction device  67 . The prediction signal may include directional information corresponding to the host vehicle direction of travel and road curvature. The pattern signal may be directed in various directions via the smart antenna  62  to account for changes in road curvature. The prediction device  67  may include the GPS  68  as shown or may also include other road curvature and directional prediction devices such as a navigation system or other prediction systems known in the art. The prediction device may also monitor acceleration and deceleration activities of the host vehicle  52  to determine road curvature and direction of travel. The systems and methods, used within the prediction device  67 , to predict road curvature and vehicle direction of travel may be used individually or in combination depending upon the sophistication of the system  50 . For example, a navigation system may predict road curvatures that the GPS  68  may not be able to predict and vice versa. 
     In step  116 , the smart antenna controller  76  generates smart antenna control signal in response to one or a combination of the vehicle proximity signal, the global positioning signal, the global clock signal, or the vehicle mapping proximity signal. The smart antenna controller  76  may alternate between signal patterns to perform various communication functions, such as, pulling information from adjacent vehicles, beaconing communication signals in a forward, rearward, or lateral direction, or other communication functions known in the art. The communication functions may correspond to time slots such that vehicles within a given cluster of vehicles are in co-operation with each other. 
     In step  118 , the smart antenna amplifier  66  amplifies or attenuates the pattern signal before transmission depending upon the vehicle situation. Similar to the variable amplifier, as stated above. 
     In step  120 , the smart antenna  62  focuses and transmits the pattern signal to one or more vehicles in response to the smart antenna control signal. 
     The above-described steps are meant to be an illustrative example, the steps may be performed synchronously or in a different order depending upon the application. 
     Also throughout the above-described steps, the main controller  58  or the vehicle network  60  may be continuously collecting and sorting incoming vehicle related data contained within signals, such as the pattern signal, the discovery signal, the network signal, or other vehicle related signals. The vehicle related data may be stored and partitioned for the various specific functions, mentioned above. The main controller  58  may also be continuously monitoring for incoming pattern signals, or the like. 
     The present invention incorporates the advantages associated with ad hoc communication systems, smart antennas, and global positioning systems with commonly used vehicle electronic devices and additional control logic into a single inter-vehicle wireless communication and warning system. The present invention is self-supporting, has quick communication capability between vehicles, and has no single point of failure allowing safety related data to be reliably and quickly communicated. The present invention also provides quick switching, direct communication, and minimum interference of pattern signals. 
     The above-described apparatus, to one skilled in the art, is capable of being adapted for various purposes and is not limited to the following systems: automotive vehicle systems, control systems, communication systems, or other systems that may utilize a smart antenna or the like. The above-described invention may also be varied without deviating from the spirit and scope of the invention as contemplated by the following claims.