SWITCHED LINK-BASED VEHICULAR NETWORK ARCHITECTURE AND METHOD

• US 20120327840A1
• Filed: 06/23/2011
• Published: 12/27/2012
• Est. Priority Date: 06/23/2011
• Status: Active Grant

• Current Assignee: Telcordia Technologies Incorporated (Telefonaktiebolaget LM Ericsson), Toyota Infotechnology Center USA, Inc.
• Original Assignee: Telcordia Technologies Incorporated (Telefonaktiebolaget LM Ericsson)
• Inventors: Chen, Wai, Guha, Ratul, Lee, John, Fukuyama, Junichiro, Vuyyuru, Rama
• Granted Patent: US 9,245,446 B2
• Time in Patent Office: Days
• US Class Current: 370/315
• CPC Class Codes: G08G 1/163 involving continuous checking
• CPC Class Codes: H04B 7/15521 combining by calculations packets received from different stations before transmitting the combined packets as part of network coding network coding aspects for detection or prevention of errors in the information received H04L1/0076; network traffic management with optimizing of information sizing, e.g. header compression, by using assembly and disassembly of packets H04W28/065
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 12/1854 with non-centralised forwarding system, e.g. chaincast
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 45/48 Routing tree calculation
• CPC Class Codes: H04L 45/54 Organization of routing tables
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04W 40/246 Connectivity information discovery
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/04 adapted for relaying to or from another terminal or user
• CPC Class Codes: H04W 92/18 between terminal devices

Abstract

A multiple hop communications method among a plurality of moving vehicles. Each moving vehicles has a plurality of unidirectional radio. The method comprises receiving an incoming packet at one of the plurality of unidirectional radios, determining if there is an active link between each of the plurality of unidirectional radios and an unidirectional radio of a neighbor vehicle, relaying the incoming packet to the plurality of unidirectional radios having an active link and transmitting the incoming packet as an outgoing packet from at least one of the plurality of unidirectional radios. If more than one packet is received, the packets can be encoded using group coding before send the packets out as an outgoing packet.

Claims

1. A multiple hop communications method among a plurality of moving vehicles, where each of the plurality of moving vehicles has a plurality of unidirectional radios comprising:

receiving an incoming packet at one of the plurality of unidirectional radios;

determining if there is an active link between each of the plurality of unidirectional radios and an unidirectional radio of a neighbor vehicle;

relaying the incoming packet to the plurality of unidirectional radios having an active link; and

transmitting the incoming packet as an outgoing packet from at least one of the plurality of unidirectional radios.

2. The multiple hop communications method according to claim 1, further comprising:

detecting unidirectional radios of a neighbor vehicle.

3. The multiple hop communications method according to claim 2, wherein the unidirectional radio of a neighbor vehicle is detected based upon receiving a periodic broadcast from the unidirectional radio of the neighbor vehicle, the periodic broadcast including a node identifier and radio identifier for the neighbor vehicle.

4. The multiple hop communications method according to claim 3, further comprising:

storing in a detection table of the unidirectional radios, the node identifier and radio identifier for the neighbor vehicle;

setting a staleness timer for the unidirectional radio of neighbor vehicle to a variable staleness value; and

associating the staleness timer with the neighbor vehicle in the detection table.

5. The multiple hop communications method according to claim 4, further comprising:

removing a node identifier and radio identifier from the detection table when the staleness timer expires.

6. The multiple hop communications method according to claim 4, wherein the variable staleness value is based upon a speed of the neighbor vehicle and a speed of the vehicle.

7. The multiple hop communications method according to claim 4, further comprising:

forming the active link.

8. The multiple hop communications method according to claim 7, wherein the active link is formed by a two-way handshake, the two-way handshake comprising:

sending a request to a neighbor vehicle having a node identifier and radio identifier in the detection table, the request including a requesting node identifier, requesting node radio identifier, neighbor vehicle node identifier and neighbor vehicle radio identifier;

starting a request timer; and

adding a radio link to an active link table as an active link if a positive response is received from the neighbor vehicle prior to an expiration of the request timer, the active link table including the neighbor vehicle node identifier, a neighbor vehicle radio identifier and a location of the neighbor vehicle.

9. The multiple hop communications method according to claim 7, further comprising:

determining whether to form an active link between a vehicle and a neighbor vehicle having a node identifier and a neighbor vehicle radio identifier in the detection table based upon at least one selection criterion.

10. The multiple hop communications method according to claim 9, wherein the at least one selection criterion is a location of a radio corresponding to the neighboring vehicle radio identifier within a vehicle.

11. The Multiple hop communications method according to claim 8, further comprising:

removing a node identifier and radio identifier from the active link table when a second staleness timer expires.

12. The multiple hop communications method according to claim 1, further comprising:

adding the received packet into a switched packet list table.

13. The multiple hop communications method according to claim 12, further comprising:

determining if the incoming packet had been previously received based upon the switched packet list table; and

discarding the incoming packet without relaying if the incoming packet had been previously received.

14. The multiple hop communications method according to claim 12, wherein if the incoming packet had not been previously received, the method further comprises transmitting the incoming packet from all of the unidirectional radios with an active link as an outgoing packet, the transmission including a unidirectional radio which received the incoming packet.

15. The multiple hop communications method according to claim 8, wherein a sub-set of the unidirectional radios with an active link transmit the outgoing packet.

16. The multiple hop communications method according to claim 15, further comprising:

determining the sub-set of unidirectional radios.

17. The multiple hop communications method according to claim 16, wherein the determining the sub-set of unidirectional radios comprises:

initializing a switching table to be empty;

receiving, periodically a packet from a neighbor vehicle containing one-hop neighbor vehicle information for the neighbor vehicle;

updating a two-hop table using the one-hop neighbor vehicle information, said updating including adding or changing a neighbor vehicle identifier, neighbor vehicle radio identifier and location;

setting a timer for the updated two-hop table and the neighbor vehicle;

determining if the neighbor vehicle is listed in a one-hop table is only neighbor of some vehicle in the two-hop table;

adding a unidirectional radio corresponding to the neighbor vehicle to the switching table;

removing the neighbor vehicle from the one-hop and the two-hop table; and

adding, iteratively, a unidirectional link corresponding to the neighbor vehicle from the one-hop table that is linked to maximum number of vehicles in the two-hop table, removing the neighbor vehicle from the one-hop and the two-hop table.

18. The multiple hop communications method according to claim 17, wherein a unidirectional radio is determined as the sub-set if the unidirectional radio is in the switching table.

19. The multiple hop communications method according to claim 1, further comprising:

generating the incoming packet at a source vehicle.

20. The multiple hop communications method according to claim 19, wherein the generating comprises:

defining a session for the incoming packet, the session including a session identifier and at least one destination vehicle identifier;

determining a network session scope for the incoming packet, the network session scope including at least a maximum hop count;

generating a payload for the incoming packet; and

generating a header for the incoming packet including at least the session and the network session scope.

21. The multiple hop communications method according to claim 19, further comprising:

determining if the vehicle is a destination;

determining if the network session scope has been reached; and

discarding the incoming packet without relay if the network session scope has been reached.

22. A multiple hop communications method among a plurality of moving vehicles, where each of the plurality of moving vehicles has a plurality of unidirectional radios comprising:

receiving at least two incoming packets by at least one of the plurality of unidirectional radios;

determining if there is an active link between each of the plurality of unidirectional radios and an unidirectional radio of a direct neighbor vehicle;

encoding the at least two incoming packets using group coding;

relaying a different encoded packet to each unidirectional having an active link; and

transmitting the different encoded packet as outgoing packets from each unidirectional having an active link, respectively.

23. The multiple hop communications method according of claim 22, wherein the encoding comprises:

mapping the at least two incoming packets into one outgoing packet for each unidirectional radio having an active link using a plurality of mapping coefficients.

24. The multiple hop communications method according of claim 22, wherein the mapping is a linear combination of the at least two incoming packets and the mapping coefficients are randomly determined.

25. A mobile wireless communications device comprising:

a plurality of unidirectional radios, at least one of the plurality of unidirectional radios being located on each side of the mobile wireless communications device; and

a processor for determining if there is an active link between each of the plurality of unidirectional radios and an unidirectional radio of a neighbor vehicle and relaying an incoming packet to a plurality of unidirectional radios having an active link, the incoming packet being transmitted as an outgoing packet from at least one of the plurality of unidirectional radios.

26. The mobile wireless communications device of claim 25, wherein the unidirectional radios of a neighboring vehicle is detected based upon receiving a periodic broadcast from the unidirectional radio of the neighbor vehicle, the periodic broadcast including a node identifier and radio identifier for the neighbor vehicle.

27. The mobile wireless communications device of claim 26, further comprising:

a storage device for storing a detection table having detection information for each of the unidirectional radios; and

a staleness timer set to a variable staleness value for each of the unidirectional radio of neighbor vehicle.

28. The mobile wireless communications device of claim 27, wherein the processor removes a node identifier and radio identifier from the detection table when the staleness timer expires.

29. The mobile wireless communications device of claim 27, further comprising:

a request timer;

wherein the storage device stores an active link table having link information for each of the plurality of unidirectional radios, wherein the processor forms the active link by sending a request to a neighbor vehicle having a node identifier and radio identifier in the detection table associated with one of the plurality of unidirectional radios, the request including a requesting node identifier, requesting node radio identifier, neighbor vehicle node identifier and neighbor vehicle radio identifier, starts the request timer; and

adds a radio link to an active link table as an active link if a positive response is received from the neighbor vehicle prior to an expiration of the request timer, the active link table including the neighbor vehicle node identifier, a neighbor vehicle radio identifier and a location of the neighbor vehicle.

30. The mobile wireless communications device of claim 29, wherein the storage device stores a switched packet list table having active links used for transmitting a received packet, wherein the processor adds a received packet into the switched packet list table that corresponds to the unidirectional radio that received the packet.

31. The mobile wireless communications device of claim 30, wherein the processor determines if the incoming packet had been previously received based upon the switched packet list table and discards the incoming packet without relaying if the incoming packet had been previously received.

32. The mobile wireless communications device of claim 31, wherein if the incoming packet had not been previously received, the incoming packet is transmitted from all of the unidirectional radios having an active link as an outgoing packet, the transmission including a unidirectional radio which received the incoming packet.

33. The mobile wireless communications device of claim 31 wherein a sub-set of the unidirectional radios with an active link transmit the outgoing packet.

34. The mobile wireless communications device of claim 33, further comprising:

an updated timer,

wherein the storage device stores a one-hop and a two-hop table, and wherein the processor determines a sub-set of the unidirectional radios with an active link for transmitting the outgoing packet by

initializing a switching table to be empty;

periodically receiving a packet from a neighbor vehicle containing one-hop neighbor vehicle information for the neighbor vehicle;

updating a two-hop table using the one-hop neighbor vehicle information, the updating including adding or changing a neighbor vehicle identifier, neighbor vehicle radio identifier and location;

setting the update timer for the updated two-hop table and the neighbor vehicle;

determining if the neighbor vehicle is listed in a one-hop table is only neighbor of some vehicle in the two-hop table;

adding a unidirectional radio corresponding to the neighbor vehicle to the switching table;

removing the neighbor vehicle from the one-hop and the two-hop table; and

adding, iteratively, a unidirectional link corresponding to the neighbor vehicle from the one-hop table that is link to a maximum number of vehicles in the two-hop table, removing the neighbor vehicle from the one-hop and the two-hop table, all active links in the switching table transmit the outgoing packet.

35. A computer readable storage device having a program of instructions for causing a computer to execute the method of:

receiving an incoming packet at one of a plurality of unidirectional radios in a mobile device;

determining if there is an active link between each of the plurality of unidirectional radios and an unidirectional radio of another mobile device;

relaying the incoming packet to the plurality of unidirectional radios having an active link; and

transmitting the incoming packet as an outgoing packet from at least one of the plurality of unidirectional radios.

36. A computer readable storage device having a program of instructions for causing a computer to execute the method of:

receiving at least two incoming packets from at least one of a plurality of unidirectional radios;

determining if there is an active link between each of the plurality of unidirectional radios and an unidirectional radio of a direct neighbor mobile device;

encoding the at least two incoming packets using group coding;

relaying a different encoded packet to each unidirectional having an active link; and

transmitting the different encoded packet as outgoing packets from each unidirectional having an active link, respectively.

37. The computer readable storage device of claim 36, wherein encoding comprises:

mapping the at least two incoming packets into one outgoing packet for each unidirectional radio having an active link using a plurality of mapping coefficients.

38. The computer readable storage device of claim 37, wherein the mapping is a linear combination of the at least two incoming packets and the mapping coefficients are randomly determined.