# US 8,570,994 B2 · Systems and methods for multi-beam optic-wireless vehicle communications > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,570,994 B2 - Document ID: US8570994B2 - Status: Granted - Kind: B2 - Application number: 13/276,375 - Filed: 2011-10-19 - Published: 2012-04-19 - Granted: 2013-10-29 - Earliest claimed: 2008-07-23 - Assignees: Telcordia Technologies, Inc.; Toyota Infotechnology Center, U.S.A., Inc. - Applicants: Wai Chen; John Lee; Ratul K. Guha; Ryokichi Onishi; Rama Vuyyuru - Inventors: Wai Chen; John Lee; Ratul K. Guha; Ryokichi Onishi; Rama Vuyyuru - Web page: https://patentgrep.com/patent/US8570994B2 ## CPC - H04W 84/18: Self-organising networks, e.g. ad-hoc networks or sensor networks - H04W 4/90: Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS] - H04W 76/50: for emergency connections - H04W 4/06: Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services - H04W 40/06: based on characteristics of available antennas - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract The present invention offers systems and methods for effective multiple-hop routing, multicasting and media access control for vehicle group communications that employ directional wireless radio technology. Multi-beam optic-wireless media and streamlined operations provide low-overhead communications among vehicles. Systems and methods are provided to maintain a quasi-stationary group of neighboring vehicles, enable high-throughput on-demand switching among multiple vehicles, enable group coding in the vehicle group to achieve higher throughput, and enable dynamic adjustment of link to maintain desirable vehicle group. The proposed solution builds upon the conception of a MAC-free wireless operation and quasi-stationary vehicular switched network to achieve ultra-low-overhead and high-throughput vehicle communications. ## Claims ### Claim 1 A vehicular ad-hoc network (VANET), comprising: a first vehicle having a plurality of antennas; a first neighbor vehicle that transmits a data packet that is received by said first vehicle via a first antenna out of the plurality of antennas; a second neighbor vehicle to receive said data packet send by said first vehicle via a second antenna out of the plurality of antennas; and said first vehicle further comprising a switching unit to transfer the data packet between said first and second antennas; wherein communication between an antenna of a neighbor vehicle and an antenna out of the plurality of antennas of the first vehicle further comprises at least one directional radio link, and wherein the data packet further comprises metadata including an antenna ID, neighbor vehicle ID, initial location, hop count, sequence number, and application attributes; and wherein the switching unit generates a Switched Packet List (SPL), said SPL comprising a source ID, sequence number for the data packet, acknowledgement status, and a cached copy of the data packet. ### Claim 2 (depends on 1) The VANET of claim 1, further comprising: a unit to generate a link table for each antenna of said plurality of antennas on the first vehicle, said link table including records for each neighbor vehicle within communication range of said each antenna, and at least attributes comprising bandwidth and link lifetime for each directional radio link with said each neighbor vehicle. ### Claim 3 (depends on 2) The VANET of claim 2, wherein the link table for each antenna is updated at a frequency that is a function of a relative speed of the first vehicle, and wherein records for neighbor vehicles that are not updated are purged after a set time. ### Claim 4 (depends on 1) The VANET of claim 1, wherein the first vehicle maintains a neighbor table comprising records for each directional radio link, said records including information about each antenna and the vehicle ID of the directional radio link. ### Claim 5 (depends on 4) The VANET of claim 4, wherein the records further comprise at least information pertaining to the link comprising a MAC address and IP address of the antenna and the neighbor vehicle. ### Claim 6 (depends on 1) The VANET of claim 1, wherein the switching unit discards an incoming data packet if a record for said incoming data packet exists in the SPL. ### Claim 7 (depends on 1) The VANET of claim 1, wherein the switching unit discards an incoming data packet if an acknowledgement status for said incoming data packet is affirmative. ### Claim 8 (depends on 1) The VANET of claim 1, further comprising a switching table showing a status of all direct radio links between vehicles in the network, and a spanning tree comprising information on each outgoing link. ### Claim 9 (depends on 8) The VANET of claim 8, wherein the switching table comprises a source field, incoming field, and outgoing field, wherein the incoming and outgoing fields are obtained based on the outgoing links in the corresponding source spanning tree. ### Claim 10 (depends on 1) The VANET of claim 1, wherein the first vehicle forwards the data packet only to selected neighbors. ### Claim 11 (depends on 10) The VANET of claim 10, further comprising a Neighboring Information Table (NIT) comprising neighbors for the first vehicle and associated active links for each neighbor and neighbors for each neighbor. ### Claim 12 (depends on 11) The VANET of claim 11, further comprising a switching table showing status of incoming and outgoing direct radio links between the first vehicle and the plurality of neighbor vehicles, wherein the outgoing radio links are determined based on a comparison of immediate neighbors of the first vehicle and immediate neighbors of the neighbor vehicle. ### Claim 13 (depends on 1) The VANET of claim 1, further comprising: a group coding manager configured to perform the following operations: splitting the data packet into a plurality of blocks; randomly selecting coefficients from a finite field; taking a linear combination of the blocks with said coefficients; and embedding the coefficients in the data packet to form a coded block; wherein said coded block is transmitted via a plurality of intermediate vehicles to a destination vehicle whereupon the group coded block is decoded through a matrix inversion operation in a finite field.