V2V SYSTEM WITH A HYBRID PHYSICAL LAYER

• US 20150131637A1
• Filed: 04/23/2013
• Published: 05/14/2015
• Est. Priority Date: 04/24/2012
• Status: Active Grant

• Current Assignee: Zetta Research and Development LLC - FORC Series, Zetta Research and Development LLC (Zetta Research, LLC)
• Original Assignee: Zetta Research and Development LLC - FORC Series
• Inventors: Rubin, Kim, Betts-Lacroix, Joe
• Granted Patent: US 9,552,727 B2
• Time in Patent Office: Days
• US Class Current: 370/337
• CPC Class Codes: B60R 2325/205 Mobile phones
• CPC Class Codes: B60R 25/33 of global position, e.g. by providing GPS coordinates
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 10/20 including control of steering systems
• CPC Class Codes: B60W 2556/50 of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: B60W 50/14 Means for informing the driver, warning the driver or prompting a driver intervention
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: G01C 21/3658 Lane guidance
• CPC Class Codes: G01C 21/3822 Road feature data, e.g. slope data
• CPC Class Codes: G01S 5/0027 of actual mobile position, i.e. position determined on mobile
• CPC Class Codes: G08G 1/09 Arrangements for giving variable traffic instructions railroad crossing signals B61L; reflectors E01F, G08B; indicating arrangements for variable information by selection or combination of individual elements G09F9/00
• CPC Class Codes: G08G 1/096791 where the origin of the information is another vehicle
• CPC Class Codes: G08G 1/0969 having a display in the form of a map
• CPC Class Codes: G08G 1/142 external to the vehicles
• CPC Class Codes: G08G 1/16 Anti-collision systems road vehicle drive control systems for predicting or avoiding probable or impending collision otherwise than by control of a particular sub-unit B60W30/08
• CPC Class Codes: G08G 1/161 Decentralised systems, e.g. inter-vehicle communication
• CPC Class Codes: G08G 1/163 involving continuous checking
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes
• CPC Class Codes: G08G 1/167 Driving aids for lane monitoring, lane changing, e.g. blind spot detection
• CPC Class Codes: G08G 1/20 : Monitoring the location of vehicles belonging to a group, e.g. fleet of vehicles, countable or determined number of vehicles
• CPC Class Codes: G08G 9/02 : Anti-collision systems
• CPC Class Codes: H04J 3/1694 : Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers Passive Optical Networks H04Q11/0062
• CPC Class Codes: H04L 5/0091 : Signaling for the administration of the divided path
• CPC Class Codes: H04W 4/027 : using movement velocity, acceleration information
• CPC Class Codes: H04W 4/06 : Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 4/46 : for vehicle-to-vehicle communication [V2V]
• CPC Class Codes: H04W 4/48 : for in-vehicle communication
• CPC Class Codes: H04W 56/0035 : detecting errors in frequency or phase
• CPC Class Codes: H04W 64/006 : with additional information processing, e.g. for direction or speed determination
• CPC Class Codes: H04W 72/0446 : Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/30 : Resource management for broadcast services
• CPC Class Codes: H04W 74/0816 : with collision avoidance
• CPC Class Codes: H04W 76/14 : Direct-mode setup
• CPC Class Codes: H04W 76/40 : for selective distribution or broadcast

Abstract

A vehicle-to-vehicle (V2V) communication transponder for use in V2V communication, safety and anti-collision systems using a hybrid protocol combining time-division multiplexed access (TDMA), with collision sense multiple access (CSMA) protocol. The TDMA frame is broken into regions, a priority and emergency TDMA region, and a non-priority CSMA region. The sizes of the TDMA regions change dynamically based on demand, with the CSMA region using the remaining time slots. Transponders self-select time slots; selected slots are held until a new time slot selection criteria; all transponders participate in notifying a transponder of a time slot message collision. An inter-transmission guard time may be dynamic based on range. Embodiments are free of MAC and IP addresses. No central authority or road-side equipment (RSU) is required. Embodiments include equipped vehicles and V2V system using the transponder.

Claims

1. A vehicle-to-vehicle (V2V) communication transponder adapted to operated in a first vehicle wherein the transponder is adapted to accept as input a subject vehicle position and a subject vehicle heading, and wherein the transponder is adapted to transmit V2V safety messages comprising:

(i) the subject vehicle position;

(ii) the subject vehicle heading; and

(iii) a subject vehicle speed;

wherein the improvement is;

the transponder uses a basic time interval (“

frame”

) of predetermined duration wherein the frame repeats continuously;

wherein the frame comprises n time slots of predetermined duration, enumerated and contiguous;

wherein the frame is subdivided into a priority class region comprising contiguous time slots from a first time slot S1 to a last time slot S2; and

a non-priority class region comprising contiguous time slots from a first time slot S3 to a last time slot S4;

wherein the range S1 to S2 and the range S3 to S4 do not overlap;

wherein the transponder transmits only time-critical V2V safety messages in the priority class region;

wherein the transponder broadcasts a V2V safety message in a self-selected time slot in the priority class region in every frame;

wherein the self-selected time slot is the same time slot for every frame until a new time slot is self-selected by the transponder;

wherein the transponder manages message broadcasts in the non-priority class region using CSMA protocol.

2. The vehicle-to-vehicle (V2V) communication transponder of claim 1 wherein:

the size of the priority class region, defined by the number S2−

S1+1, is adjusted after each frame responsive to the number of empty priority class region time slots in the prior frame; and

wherein the size of the non-priority class region, defined by the number S4−

S3+1, is adjusted after each frame by an equal and opposite number of frames in the priority class region, such that the sum of the sizes of the priority and non-priority class regions remains constant.

3. The vehicle-to-vehicle (V2V) communication transponder of claim 1 wherein:

the size of the priority class region, defined by the number S2−

S1+1, is adjusted after each frame to the larger of;

(i) S2=SX where SX is the highest number non-empty time slot with a priority class transmission, and (ii) a size such that the number of empty time slots in the priority class region is a predetermined number.

4. The vehicle-to-vehicle (V2V) communication transponder of claim 1 wherein:

the frame is further subdivided into an emergency class region comprising contiguous time slots from a first time slot S5 to a last time slot S6 and the range S5 to S6 does not overlap with either the range S1 to S2 or the range S3 to S4;

wherein the emergency class region is restricted to messages transmitted from emergency vehicles or from government authorized road-side units (RSUs);

wherein when a transponder broadcasts a V2V safety message in the emergency class region it uses one self-selected emergency time slot in every frame;

wherein the self-selected emergency time slot is the same time slot for every frame until a new self-selected emergency time slot is self-selected by the transponder or the transponder stops sending messages in the emergency class region.

5. The vehicle-to-vehicle (V2V) communication transponder of claim 4 wherein:

the size of the priority class region, defined by the number S2−

S1+1, is adjusted after each frame responsive to the number of empty priority class region time slots in the prior frame; and

the size of the emergency class region, defined by the number S6−

S5+1, is adjusted after each frame responsive to the number of empty emergency class time slots in the prior frame;

wherein the size of the non-priority class region, defined by the number S4−

S3+1, is adjusted after each frame, such that the sum of the sizes of the priority, emergency non-priority class regions, and any buffer regions, remains constant.

6. The vehicle-to-vehicle (V2V) communication transponder of claim 1 wherein:

the wireless encoding method, for a particular message broadcast in the priority class region, is responsive to the amount of data in the particular message such that the time length of the particular message is equal to or less than the available transmission time within one time slot.

7. The vehicle-to-vehicle (V2V) communication transponder of claim 1 wherein:

an inter-transmission guard time between transmissions in the priority class region is no longer than the intended operating distance of a V2V communication system using the transponder, for messages in the priority class region, divided by the speed of light;

plus two times the allowable time base error of the transponder.

8. The vehicle-to-vehicle (V2V) communication transponder of claim 1 wherein:

an inter-transmission guard time between transmissions in the priority class region is shorter than an inter-transmission guard time between transmissions in a different priority class region.

9. The vehicle-to-vehicle (V2V) communication transponder of claim 1 wherein:

the self-selected time slot is randomly selected from a set of time slots that were empty in at least the immediately prior frame and within the currently determined class region;

subject to a monotonic, statistical weighting function such that the probability of selecting a first time slot T1 is equal to or higher than the probability of selecting a second time slot T2 wherein T1 is closer to S1 than is T2, and that at least for some T1 and T2, the probability of selecting T1 is higher than the probability of selecting T2.

10. The vehicle-to-vehicle (V2V) communication transponder of claim 1 wherein:

the transponder self-selects a new time slot when;

(i) a time slot holding timer expires, and (ii) the current time slot is not a time slot that might be self-selected by the transceiver for the current frame, if it were empty.

11. The vehicle-to-vehicle (V2V) communication transponder of claim 1 wherein:

the transponder self-selects a new time slot when it receives a message collision message identifying either;

(i) the subject vehicle for which the transponder is sending messages, or (ii) the time slot in which the transponder is sending messages.

12. The vehicle-to-vehicle (V2V) communication transponder of claim 1 wherein:

the transponder is adapted to detect a “

message collision,”

that is, when two or more messages sent by transponders within receive range of the transponder transmit in the same time slot;

wherein the transponder transmits a “

message collision message”

in response to the detection of a message collision wherein the message collision message identifies either (i) a vehicle location for a subject vehicle whose location was in one of the colliding messages;

or (ii) the time slot of the message collision;

subject to the exclusion wherein the transponder does not send a message collision message if the transponder has received a predetermined minimum quantity of message collision messages identifying the same message collision as the message collision message it would have sent.

13. The vehicle-to-vehicle (V2V) communication transponder of claim 1 wherein:

the only vehicle identification in a V2V safety message is the subject vehicle position.

14. The vehicle-to-vehicle (V2V) communication transponder of claim 1 wherein:

V2V safety messages are sent in cleartext; and

wherein the vehicle safety messages are free of MAC addresses and free of IP addresses.

15. The vehicle-to-vehicle (V2V) communication transponder of claim 1 wherein:

the timing of valid messages received in the priority class region are used by the transponder to adjust the transponder'"'"'s time base so as to create a dynamic, continually updated, consensus-group time base wherein the consensus group comprises vehicles sending and receiving valid messages in the priority class; and

wherein the validity of such messages is determined, at least in part, by the transponder having a distance metric, between the sending and receiving transponders, within a predetermined accuracy.

16. A vehicle-to-vehicle (V2V) communication system using a plurality of vehicles, each equipped with a transponder of claim 1.

17. A vehicle equipped with a transponder of claim 1 wherein the subject vehicle is the equipped vehicle.