Systems and methods for accessing an air-to-ground network

Abstract

Systems and methods for establishing a connection between a vehicle and a base station are provided. A base station sector is divided into sub-sectors each associated with a narrow beam antenna. To determine the position of the vehicle without using a complementary network, the base station and the vehicle may associate each sub-sector with a corresponding set of radio access preamble sequences. Accordingly, the position of the vehicle may be determined based on a particular radio access preamble sequence included in a synchronization message exchange. Additionally or alternatively, the base station may be configured to sequentially activate the narrow beam antennas to detect which narrow beam is active when the vehicle responds to a message transmitted via a narrow beam.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of U.S. Patent Application No. 16 / 799,374, filed on February 24, 2020, titled "SYSTEMS AND METHODS FOR ACCESSING AN AIR-TO-GROUND NETWORK", the entire disclosure of which is hereby incorporated by reference in its entirety. TECHNICAL FIELD

[0003] The following disclosure relates to systems and methods for accessing an air-to-ground network, and more particularly to synchronizing network access between a vehicle and a ground base station. BACKGROUND OF THE INVENTION

[0004] Ground base stations in air-to-ground networks are often associated with large coverage areas. In addition, in many air-to-ground networks, each individual base station serves a relatively small number of vehicles. Accordingly, air-to-ground networks implementing antenna steering techniques need to know where to steer the antenna in order to communicate with vehicles located within the coverage area.

[0005] One solution is to utilize a secondary network that does not rely on antenna steering techniques for position determination. However, secondary networks are not universally implemented. In addition, this creates an additional dependency for air-to-ground networks associated with additional points of failure. Accordingly, in order to improve the stability of air-to-ground networks implementing antenna steering techniques, systems and methods for accessing an air-to-ground network that do not rely on a secondary network are needed. SUMMARY OF THE INVENTION

[0006] In one embodiment, a method for a vehicle to establish a connection with a base station is provided. The method includes (1) determining, by the one or more processors, the number of sub-sectors into which a spatial sector served by the base station is divided; (2) associating, by the one or more processors, the sub-sectors with corresponding non-overlapping sets of random access sequences; (3) receiving, from the base station, a synchronization message including an identifier of the base station; (4) determining, by the one or more processors, a particular sub-sector in which the vehicle is located based on a relative position between the vehicle and the base station; (5) identifying, based on the determined sub-sector, a particular set of random access sequences by the one or more processors; and (6) transmitting a random access channel (RACH) preamble message to the base station, wherein the RACH preamble message includes a particular random access sequence corresponding to the particular sub-sector from within the particular set of random access sequences.

[0007] In another embodiment, a method for a base station to establish a connection with a vehicle is provided. The method includes (1) causing, by one or more processors, sub-sectors of the base station to correspond to respective non-overlapping sets of random access sequences; (2) broadcasting a synchronization message including an identifier of the base station; (3) receiving, from the vehicle, a random access channel (RACH) preamble message including a random access sequence; (4) identifying, by the one or more processors, a specific sub-sector of the base station corresponding to the random access sequence included in the RACH preamble message; (5) activating, by the one or more processors, a narrow beam directed to the specific sub-sector; and (6) transmitting a RACH response (RAR) message to the vehicle via the narrow beam.

[0008] In yet another embodiment, a method for a base station to establish a connection with a vehicle is provided. The method includes (1) dividing, by one or more processors, a sector of the base station into a plurality of sub-sectors; (2) configuring, by the one or more processors, an antenna array to associate the plurality of sub-sectors with respective narrow beams; (3) broadcasting, by the one or more processors, a synchronization message including an identifier of the base station; (4) receiving, from the vehicle, a random access channel (RACH) preamble message including a random access (RA) sequence; (5) sequentially activating, by the one or more processors, the narrow beams associated with the plurality of sub-sectors; (6) when a specific narrow beam associated with a specific sub-sector is activated, (i) determining that the RA sequence included in the RACH preamble message corresponds to the specific sub-sector, and (ii) in response to the determination, broadcasting a RACH response (RAR) message via the specific narrow beam; (7) receiving a radio resource control (RRC) connection request from the vehicle; and (8) causing, by the one or more processors, the vehicle to be associated with the sub-sector corresponding to the narrow beam, the narrow beam being in an active state when the RAR message is transmitted. Description of the Drawings

[0009] Figure 1 An embodiment of an exemplary communication system capable of performing one or more of the synchronization techniques disclosed herein is depicted;

[0010] Figure 2A Illustrates an example process that can be implemented in Figure 1 a communication system in which a vehicle selects a specific random access sequence to establish communication with a base station;

[0011] Figure 2B Illustrates an example Figure 2A random access sequence selection process implemented in

[0012] Figure 3A Illustrates a base station in a communication system that can be implemented in Figure 1 sequentially activating beams associated with multiple sectors;

[0013] Figure 3B An example signal diagram showing the sequential activation process of an implementation Figure 3A ;

[0014] Figures 4A - 4B showing the transmission power of a base station in a communication system that can be implemented in Figure 1 dividing the beam among multiple frequency carriers;

[0015] Figure 5 is a flowchart of an example method for a vehicle to establish communication with a base station in the communication system depicted in Figure 1 ;

[0016] Figure 6 is a flowchart of an example method for a base station to establish communication with a vehicle in the communication system depicted in Figure 1 ;

[0017] Figure 7 is a flowchart of another example method for a base station to establish communication with a vehicle in the communication system depicted in Figure 1 ;

[0018] Figure 8 is a block diagram of a vehicle controller, such as a vehicle controller depicted in Figure 1 , that facilitates the synchronization techniques disclosed herein; and

[0019] Figure 9 is a block diagram of a base station controller, such as a base station controller depicted in Figure 1 , that facilitates the synchronization disclosed herein. Detailed Description

[0020] Although the following presents a detailed description of many different embodiments, it should be understood that the legitimate scope of the description is defined by the language of the claims and their equivalents set forth at the end of this patent. The detailed description should be construed as merely exemplary and does not describe every possible embodiment, as it would be impractical to describe every possible embodiment. Many alternative embodiments can be implemented using current technology or technology developed after the filing date of this patent, and such alternative embodiments will still fall within the scope of the claims.

[0021] It should be understood that, unless a term is explicitly limited by a sentence such as "As used herein, the term '__' is hereby defined to mean..." or a similar sentence in this patent, there is no intention to limit the meaning of the term (whether explicitly or by implication) beyond its ordinary or common meaning, and the term should not be construed as being limited in scope based on any statement made in any section of this patent (except the language of the claims). For any term recited in the claims appended to this disclosure that is referred to in the singular in this disclosure, this is done for simplicity only so as not to confuse the reader, and it is not intended that the claim term be limited by implication or otherwise to the recited singular meaning. Finally, unless a claim element is limited by the recitation of the word "means" and a function without any recitation of structure, it is not intended that the scope of any claim element be construed based on the application of 35 U.S.C. § 112(f).

[0022] As used throughout this document, "synchronization" refers to the process of establishing a communication link between a vehicle and a base station. For example, the communication link can be a Long Term Evolution (LTE) or New Radio (NR) / Fifth Generation (5G) communication link. Although the LTE and NR communication protocols state procedures for how to establish a connection, if the distance between the base station and the vehicle is large enough, the base station and the vehicle need to know each other's respective positions in order to send and receive the messages stated in the protocol. Since the base station is typically fixed, a base station database associating the base station identifier with its geographical location can be stored on the vehicle. Thus, when the vehicle receives a message from the base station, the vehicle can query this database to determine how to orient the vehicle antenna to communicate back to the base station. However, vehicles are typically not fixed. Therefore, a communication system can implement the presently disclosed techniques to orient the base station antenna to communicate with the vehicle.

[0023] Figure 1 An environment 100 depicting an example communication system capable of performing the vehicle-base station synchronization techniques described herein is shown. Environment 100 can include a vehicle 105 communicating with a base station 145 via a communication link 130. Although vehicle 105 is depicted as an airplane, it is contemplated that vehicle 105 can be any vehicle, such as a bus, train, subway, helicopter, ship, subway, hot air balloon, etc. Additionally, although Figure 1 only a single vehicle 105 is shown, in other embodiments, the environment can include any number of vehicles configured to perform the synchronization techniques described herein. As shown, vehicle 105 is equipped with a vehicle controller 120 that supports communication external to vehicle 105 via communication link 130.

[0024] The vehicle controller 120 is coupled to a base station database 122 configured to store information about base station 145 (and any other base stations included in the communication network). For example, the base station database 122 may include a data table associating base station identifiers with the geographical locations of the corresponding base stations. To this end, communications received from base station 145 may be configured to include a base station identifier corresponding to base station 145. As will be elaborated below, the data table of the base station database 122 may include fields associating the sectors of base station 145 with the corresponding random access (RA) sequences utilized during the synchronization process. In some embodiments, the base station database 122 includes a primary mapping of sub-sectors to RA sequences based on the relative positioning of base station sectors. In other embodiments, the base station database 122 may associate a base station with a different mapping of sub-sectors to RA sequences.

[0025] In addition, the vehicle controller 120 is operatively connected to one or more modems 115 configured to support communications via transceivers 108 and 109. For example, the modem 115 may be configured to support corresponding communication protocols (e.g., TDMA, GSM, CDMA, GSM, LTE, WiMAX, NR, Wi-Fi, etc.) at corresponding frequency bands (e.g., Ka band, K band, L band, S band, cellular band, AWS band, PCS band, unlicensed band, etc.). In the illustrated embodiment, transceiver 109 may be adapted to communicate via one or more satellite communication links (e.g., using a modem 115 supporting satellite communication bands), and transceiver 108 may be adapted to communicate with base station 145 via communication link 130. a band, K u band, L band, S band, cellular band, AWS band, PCS band, unlicensed band, etc.). In the illustrated embodiment, transceiver 109 may be adapted to communicate via one or more satellite communication links (e.g., using a modem 115 supporting satellite communication bands), and transceiver 108 may be adapted to communicate with base station 145 via communication link 130.

[0026] In some embodiments, transceiver 108 includes a phased antenna array configured to generate beamforming directed towards base station 145. For example, after the vehicle 105 and the base station 145 are synchronized, the vehicle controller 120 may determine the relative position between the vehicle 105 and the base station 145. Based on the relative position, the transceiver 108 may be configured to generate beamforming with a large gain directed towards the position of the base station 145.

[0027] Similarly, the base station 145 includes a base station controller 140 configured to control the operation of the antenna 142 thereat. As shown, the base station 145 is connected to a public switched telephone network (PSTN) 190 and the Internet 192 (which may include a voice over Internet protocol (VOIP) network). Accordingly, any data received by the base station 145 from the vehicle 105 may be delivered to the indicated destination outside the communication network. In addition, the base station 145 may be configured to receive communications from the Internet 192 and / or the PSTN 190 to effect forward link communication to the vehicle 105 via the communication link 130.

[0028] In some embodiments, the antenna 142 is a phased antenna array configured to be electronically and / or mechanically steered by the base station controller 140. To this end, the base station controller 140 may be configured to control the antenna 142 to generate one or more beamformings. For example, the base station controller 140 may control the antenna 142 to generate a wide beam that spreads the transmission power over a relatively large angular range (e.g., the entire sector, or 60° in a typical six-sector base station), or focus the transmission power on a narrow beam over a relatively small angular range (e.g., 8.75° if a 60° sector is divided into eight sub-sectors). It should be understood that due to the narrow distribution of the transmission power, the vehicle 105 senses a relatively large received power via the narrow beam. Therefore, the narrow beam communication link 130 can better support a large amount of data (e.g., data associated with the traffic of personal electronic devices connected to the in-vehicle network of the vehicle 105). On the other hand, since the wide beam antenna broadcasts over the entire sector, the base station controller 140 may be configured to deliver the initial synchronization signaling via the wide beam to be able to communicate with the vehicle 105, regardless of the position of the vehicle 105 when it enters the sector of the base station 145. To this end, the initial synchronization signaling typically requires less bandwidth than the traffic and does not necessarily require the additional received power associated with the narrow beam communication.

[0029] Accordingly, to support the higher data rate associated with the narrow beam communication, the base station controller 140 needs to determine the relative position of the vehicle 105 to communicate with the vehicle 105 via a narrow beam that only covers a part of the sector. In a first technique, the communication system defines non-overlapping sets of RA sequences (also referred to as "random access channel (RACH) preamble sequences") and associates each set of RA sequences with a predetermined sub-sector. For example, if the communication system divides each sector into eight sub-sectors, the communication may divide the RA sequences into eight different non-overlapping sets. The communication system may then associate each set of RACH preamble messages with a sub-sector based on the relative positioning of the sub-sectors (e.g., the first sub-sector in the clockwise azimuth corresponds to the first set of RACH preambles, the second sub-sector in the clockwise azimuth starting from the north corresponds to the second set of RACH preambles, etc.). Accordingly, both the vehicle 105 and the base station 145 store an indication of the correspondence between the RA sequences and the sub-sectors.

[0030] Now referring to Figure 2A , an example process is shown in which a particular random access sequence is selected by a vehicle 205 (e.g., Figure 1 the vehicle 105) to establish communication with a base station 245 (e.g., Figure 1 the base station 145). As shown, the base station 245 divides each sector 247 into eight sub-sectors B1 - B8 positioned in a clockwise azimuth with respect to each other. It should be understood that although Figure 2AOnly the sub - sectors of sector 247a are depicted, but each of the other sectors 247 can be similarly divided into sub - sectors.

[0031] Vehicle 205 includes a sequence mapping 222 that makes each of sub - sectors B1 - B8 correspond to a respective RA sequence. In the illustrated embodiment, there are 32 RA sequences divided among the sub - sectors, but in other instances, there may be more or fewer RA sequences. The sequence mapping 222 can be stored at Figure 1 the base station database 122 of. Accordingly, when vehicle 205 selects an RA sequence to include in a registration message, vehicle 205 can determine the sub - sector in which the vehicle is located and randomly select a sequence from the corresponding set of RA sequences. In the illustrated scenario, the vehicle is located in sub - sector B7 and randomly selects one of RA7, RA 15 , RA 23 and RA 31 . Accordingly, when vehicle 205 transmits a RACH message containing the selected RA sequence, base station 245 is able to interrogate a copy of its sequence mapping 222 to determine the relative position of vehicle 205.

[0032] Figure 2B Illustrates an example signal diagram 250 of the Figure 2A random access sequence selection process. In the signal diagram, the user equipment (UE) is vehicle 205 (or more precisely, the vehicle controller of vehicle 205, such as Figure 1 the vehicle controller 120 of), and the evolved Node B (eNB) is base station 245.

[0033] As shown, signal diagram 250 begins when base station 245 transmits a synchronization signal 252, such as a synchronization signal block (SSB) 252, which includes a physical broadcast channel (PBCH), a primary synchronization signal (PSS), and a secondary synchronization signal (SSS). As is known in the art, the combination of PSS and SSS forms a physical cell identifier (PCI) assigned to base station 245 during network planning. Additionally, the PBCH message contains an indication of the system frame name (SFN) to indicate to vehicle 205 the current frame number at base station 245. In the illustrated example, base station 245 periodically transmits the synchronization signal 252 via a wide beam covering sector 247a. Accordingly, when vehicle 205 enters sector 247a, vehicle 205 is able to determine the base station identifier to query the base station database for the physical location of base station 245 and the synchronization information required in response to synchronization signal 252.

[0034] In response to receiving the synchronization signal 252, vehicle 205 replies with a "Msg1" or RACH preamble sequence message 254 that includes an indication of a specific RA sequence. As described with respect toFigure 2A As described, vehicle 205 utilizes PCI information to determine its relative position with respect to base station 245 to identify the specific subsector B1 - B8 in which vehicle 205 is located. Accordingly, vehicle 205 formats Msg1 254 to include a RA sequence randomly selected from a set of RA sequences corresponding to the current subsector (in the Figure 2A scenario shown, which is B7). Thus, after receiving Msg1 254, base station 245 can query the RA sequence mapping to identify the specific subsector in which vehicle 205 is located.

[0035] Base station 245 is configured to respond to Msg1 254 by transmitting a "Msg2" or random access response (RAR) message 256. More specifically, base station 245 is configured to transmit Msg2 via a narrow beam covering the subsector corresponding to the RA sequence included in Msg1 254. Msg2 256 can be configured to include a timing advance (TA) to account for the timing offset used to transmit signals between vehicle 205 and base station 245, and a resource grant for vehicle 205 to subsequently transmit a radio resource control (RRC) connection request.

[0036] Vehicle 205 then transmits an RRC connection request or "Msg3" 258 according to the grant included in Msg2 256. Msg3 258 can be configured to include various identifiers associated with vehicle 205 for authenticating vehicle 205 to the communication system. Assuming vehicle 205 is properly authenticated, base station 245 replies with an RRC connection setup or "Msg4" 260 containing the configuration information required for vehicle 205 to establish an RRC connection with base station 245. After configuring a communication module (e.g., Figure 1 modem 115) with the RRC configuration information included in Msg4 260, vehicle 205 responds with an RRC connection setup complete message 262 to inform base station 245 that vehicle 205 is properly synchronized with base station 245.

[0037] At this time, vehicle 205 is synchronized with base station 245 and is capable of requesting to establish a Packet Data Network (PDN) connection (e.g., a user plane connection). Accordingly, vehicle 205 may periodically request a PDN connection to transmit location information to base station 245. For example, the location information may include an azimuth angle (e.g., an azimuth angle relative to sector 247a), a longitude-latitude pair, GPS coordinates, and / or other location identifiers obtained from a positioning sensor on vehicle 205. Based on this location information, base station 245 is able to track the location of the vehicle as it traverses the coverage area of base station 245. Thus, base station 245 may transmit subsequent forward link communications to the vehicle via different narrow beams as vehicle 205 enters different sub-sectors of base station 245.

[0038] In a second technique for determining the location of a vehicle, the base station transmits and receives messages via sequentially activated narrow beams to detect a particular narrow beam that is active when a response is received. More specifically, referring now to Figure 3A , an example process is shown in which base station 345 (e.g., Figure 1 base station 145) sequentially activates narrow beams 349. In some embodiments, the second technique may be applied to establish a forward link from base station 345. In these embodiments, a Minimum Mean Square Error (MMSE) technique may be used to receive reverse link communications from the vehicle within the coverage area of base station 345. As shown, base station 345 divides sector 347 into four sub-sectors 348a-d that are positioned in a clockwise orientation with respect to each other. It should be understood that although Figure 3A depicts base station 345 dividing sector 347 into four sub-sectors 348, in other embodiments, base station 345 may divide the sub-sectors into more or fewer sub-sectors 348.

[0039] In some embodiments, to generate narrow beams, base station 345 may include a gain profile associated with each of narrow beams 349 such that narrow beams 349 are configured to maximize the gain in the direction of the corresponding sub-sector 348. In the example shown, the gain profile of narrow beam 349a maximizes the gain in the direction of sub-sector 348a, the gain profile of narrow beam 349b maximizes the gain in the direction of sub-sector 348b, and so on. Accordingly, the base station controller (e.g., Figure 1The base station controller 140 of the embodiment of the present invention can be configured to reconfigure the phased antenna array to cycle through the gain profile associated with the narrow beam 349. In other embodiments, the base station 345 includes separate antennas that are pointed at corresponding sub-sectors 348. In these embodiments, the base station 345 can be configured to activate the corresponding antenna (and deactivate other antennas) to activate a particular narrow beam. Although the illustrated embodiment depicts the base station 345 sequentially activating the narrow beams 349 in a clockwise manner, in other embodiments, the base station 345 can sequentially activate the narrow beams 349 in a counterclockwise manner or stagger the activation of the narrow beams 349 (e.g., activating narrow beams 349a, 349c, 349b, then 349d).

[0040] Figure 3B Show implementation Figure 3A The sequential narrow beam activation technique is used to determine the vehicle 305 (e.g., Figure 1 305). In the signal diagram, the user equipment (UE) is the vehicle 305 (or more specifically, the vehicle controller of the vehicle 305, such as Figure 1 The vehicle controller 120), and the evolved Node B (eNB) is the base station 345.

[0041] Similar to signal diagram 250, signal diagram 350 begins when base station 345 transmits a synchronization signal 352, such as a synchronization signal block (SSB), which includes the PBCH, PSS, and SSS. In response to receiving synchronization signal 352, vehicle 305 replies with a "Msg1" or RACH preamble sequence message 354. Unlike signal diagram 250, Msg1 354 does not include a specific RA sequence associated with a specific sub-sector 348 of sector 347. In other words, the RA sequence included in Msg1 354 can be any one of the available RA sequences. Therefore, when base station 345 receives Msg1 354, base station 345 still does not know the sub-sector 348 in which vehicle 305 is located for delivering forward link communications.

[0042] Accordingly, the base station 345 is configured to Figure 3AThe described technique sequentially activates narrow beam 349 to transmit Msg2 356. More specifically, base station 345 sequentially activates narrow beam 349 for a duration sufficient to receive a response from vehicle 305. If the duration expires and base station 345 does not receive a response, base station 345 activates the next sequential narrow beam 349 and retransmits Msg2 356. On the other hand, when base station 345 activates narrow beam 349 corresponding to the subsector 348 where vehicle 305 is located, vehicle 305 can detect Msg2 356 and respond with Msg3 358. Thus, when base station 345 detects Msg3 358, base station 345 associates vehicle 305 with the current subsector 348.

[0043] Accordingly, when base station 345 responds with Msg4 360, base station 345 transmits Msg4 360 via narrow beam 349 corresponding to the associated subsector 348. After vehicle 305 and base station 345 synchronize following Msg4 360, vehicle 305 requests to establish a PDN connection 362 (e.g., a user plane connection). For example, vehicle 305 can periodically request PDN connection 362 to transmit location information to base station 345. Based on this location information, base station 345 is able to track the location of vehicle 305 as vehicle 305 traverses the coverage area of base station 345. Thus, base station 345 can transmit subsequent forward link communications to vehicle 305 via different narrow beams 349 as vehicle 305 enters different subsectors 348 of base station 345.

[0044] It should be understood that although base station 345 is described above as sequentially activating narrow beam 349 to transmit Msg2 356, in other embodiments, base station 345 instead sequentially activates narrow beam 349 to transmit SSB 352. Accordingly, when base station 345 detects Msg1 354, base station 345 can associate vehicle 305 with the specific narrow beam 349 via which SSB 352 is transmitted. Thus, in these embodiments, when base station 345 transmits Msg2 356, base station 345 transmits Msg2 356 via the specific narrow beam 349 associated with vehicle 305.

[0045] Figures 4A - 4B Illustrated is the division of the transmission power of a beam among multiple frequency carriers by a base station that can be implemented in Figure 1 a communication system. Due to regulatory requirements and / or operator-specific link budget constraints, a base station (e.g., Figure 1 base station 145) typically has a maximum effective radiated power (ERP) for forward link communication to a vehicle (e.g., Figure 1 vehicle 105). Accordingly, in Figure 4AIn curve 400, the base station focuses all gains on a single frequency carrier f. Thus, when the base station transmits a message via a single-carrier wide beam, the gain difference between wide-beam communication and narrow-beam communication is mitigated. Accordingly, when using a single carrier, vehicles farther from the base station are more likely to detect the wide-beam signal. This is effective when transmitting initial synchronization message exchanges (e.g., synchronization signals 252 and 352 and / or Msg2 256 and 356 for Figure 2B and Figure 3B respectively). Figure 2B and Figure 3B respectively).

[0046] Nonetheless, many communication systems employ multiple carriers that can be used for communication between the base station and user equipment. Accordingly, if a vehicle is configured to support multiple carriers, the vehicle may not be tuned to frequency f when entering the coverage area of the base station. Thus, the base station can be configured to cycle between the supported carriers when broadcasting initial synchronization message exchanges.

[0047] Alternatively, as shown in curve 450 of Figure 4B , the base station can use a wide beam to broadcast synchronization message exchanges simultaneously via each of carriers f1, f2, and f3. In these embodiments, the vehicle is more likely to be tuned to the transmission carrier to be able to detect the broadcast message exchange and respond accordingly. However, due to regulatory ERP limitations, the transmission power for each individual carrier is proportionally less than the maximum transmission power. Figure 4B In these embodiments, the vehicle is more likely to be tuned to the transmission carrier to be able to detect the broadcast message exchange and respond accordingly. However, due to regulatory ERP limitations, the transmission power for each individual carrier is proportionally less than the maximum transmission power.

[0048] Figure 5 FIG. 500 is a flowchart of an example method for a vehicle (e.g., vehicle 105 of Figure 1 ) to establish communication with a base station (e.g., base station 145 of Figure 1 ). Specifically, the method can be executed by one or more processors of a vehicle controller (e.g., vehicle controller 120 of Figure 1 ) of the vehicle. Figure 1 to establish communication with a base station (e.g., base station 145 of Figure 1 ). Specifically, the method can be executed by one or more processors of a vehicle controller (e.g., vehicle controller 120 of Figure 1 ) of the vehicle. Figure 1 Specifically, the method can be executed by one or more processors of a vehicle controller (e.g., vehicle controller 120 of Figure 1 ) of the vehicle. Figure 1 of the vehicle.

[0049] Flowchart 500 begins at block 505, where the vehicle determines the number of subsectors into which a spatial sector served by the base station is divided. As part of a communication system in which the vehicle communicates with the base station, the sector of the base station is divided into a predetermined number of subsectors (e.g., four, six, eight, twelve). In some embodiments, this number can be programmed into the vehicle controller as part of a configuration file that enables the vehicle to communicate via a communication network that includes the base station. In other embodiments, the determination is based on the number of sets of RA sequences stored in a memory at the vehicle.

[0050] At block 510, the vehicle associates the subsectors with corresponding non-overlapping subsets of a set of RA sequences. For example, as relative to Figure 2A Figure 2AAs described, the set of RA sequences can be partitioned among the sub-sectors of a base station. In some embodiments, the communication system provides a constant correspondence between the sub-sectors and the set of RA sequences such that the correspondence is maintained regardless of the particular location of the vehicle within the communication network. As an example, the first sub-sector in the clockwise azimuth in each sector can correspond to the first set of RA sequences. Accordingly, the vehicle can store the correspondence between the sub-sectors and the set of RA sequences in a memory thereat.

[0051] At block 515, the vehicle receives a synchronization message from the base station that includes an identifier of the base station (e.g., synchronization signals 252 and 352 of Figure 2B and 3B respectively). For example, the synchronization message can be an SSB message that includes PSS and PBCH message transmissions. In some embodiments, the base station is configured to broadcast the synchronization message periodically via wide beam transmissions. In other embodiments, the base station is configured to broadcast the synchronization message via sequentially activated narrow beam transmissions. In any case, the vehicle detects the synchronization message shortly after entering the sector of the base station.

[0052] At block 520, the vehicle determines the particular sub-sector in which the vehicle is located based on the relative position between the vehicle and the base station. In some embodiments, the vehicle includes a base station database (e.g., a network map) that includes the geographical locations of the base stations within the communication network and the orientations of their corresponding sectors. Accordingly, the vehicle can query the base station database using the base station identifier included in the received synchronization message to determine the geographical location of the base station. The vehicle can then obtain position data generated by a vehicle position sensor and compare the obtained position data with the queried position of the base station to determine the relative position between the vehicle and the base station. Based on the relative position and sector orientation included in the base station database, the vehicle determines the particular sub-sector in which the vehicle is located.

[0053] At block 525, the vehicle identifies a particular set of RA sequences based on the determined sub-sector corresponding to the current position of the vehicle. For example, if the vehicle determines that it is located in the fifth sub-sector in the clockwise azimuth, the vehicle can identify the set of RA sequences based on the correspondence performed at block 510.

[0054] At block 530, the vehicle transmits a random access channel (RACH) preamble message to the base station (e.g., Figure 2B RACH / Msg1 254). More specifically, the vehicle configures the RACH preamble message to include a particular RA sequence from the particular set of RA sequences identified at block 525. In some embodiments, the vehicle randomly selects the particular RA sequence from the particular set of RA sequences.

[0055] Because the base station also knows the correspondence between the sub - sectors and the set of RA sequences, the base station knows the position of the vehicle after receiving the RACH message. Accordingly, the base station can respond with a RAR message (e.g., Figure 2B the RAR / Msg2 256) via a narrow - beam transmission. Thus, the vehicle can become synchronized with the base station using narrow - beam transmission without having to implement a complementary network. It should be understood that after the vehicle is synchronized with the base station, the vehicle can continue to update the base station with the vehicle's position for data transmitted via the PDN connection. Accordingly, based on the position data transmitted via the PDN connection, the base station can deliver forward - link communication via an appropriate narrow - beam as the vehicle traverses the coverage area of the base station.

[0056] Figure 6 is a flowchart 600 of an example method for a base station (e.g., Figure 1 the base station 145) to establish communication with a vehicle (e.g., Figure 1 the vehicle 105). Specifically, the method can be executed by one or more processors of a base - station controller (e.g., Figure 1 the base - station controller 140) of the base station.

[0057] Flowchart 600 begins at block 605, where the base station makes the sub - sectors of the base station correspond to respective non - overlapping sets of RA sequences. As described with respect to Figure 2A the set of available RA sequences can be partitioned among the sub - sectors of the base station. For example, the first sub - sector in the clockwise azimuth in each sector can correspond to the first set of RA preamble sequences. Accordingly, the base station can store the correspondence between the sub - sectors and the set of RA sequences in the memory there.

[0058] At block 610, the base station broadcasts a synchronization message (e.g., synchronization signals 252 and 352 which are Figure 2B and 3B respectively) that includes an identifier of the base station. For example, the synchronization message can be an SSB message that includes PSS and PBCH message reception. In some embodiments, the base station broadcasts the synchronization message via a wide - beam that covers the sector of the base station. In other embodiments, the base station broadcasts the synchronization message by sequentially activating the plurality of narrow - beams of the sub - sectors that cover the sector and transmitting the synchronization message after activating a particular narrow - beam.

[0059] In addition, as described with respect to Figures 4A - 4BAs described, the base station may broadcast synchronization messages (via wide beams or narrow beams) using a single carrier or multiple carriers. In embodiments where the base station broadcasts synchronization messages using a single carrier, the base station may be configured to determine available transmission power and broadcast synchronization messages via the single carrier at the determined available transmission power. In embodiments where the base station broadcasts synchronization messages via multiple carriers, the base station may be configured to divide the available transmission power among the multiple carriers and transmit synchronization messages using the respective divided transmission power associated with each of the multiple carriers.

[0060] At block 615, the base station receives a RACH preamble message from the vehicle that contains an RA sequence. For example, the RACH preamble message may be Figure 2B the RACH / Msg1 254.

[0061] At block 620, the base station identifies a particular subsector of the base station that corresponds to the RA preamble sequence contained in the RACH preamble message. To do so, the base station may be configured to compare the received RA sequence with a set of RA sequences stored therein. Based on the particular set of RA sequences that contains the received RA preamble sequence, the base station can determine the particular subsector in which the vehicle is currently located.

[0062] At block 625, the base station activates a narrow beam that points to the particular subsector. In some embodiments, the base station configures a phased antenna array with a gain profile that points to the particular subsector. In other embodiments, the base station enables a connection to a particular antenna that points to the particular subsector. It should be appreciated that in some embodiments, the narrow beam only supports forward link communication. In these embodiments, the base station may implement MMSE techniques to detect reverse link communication (including the RACH preamble message).

[0063] At block 630, the base station transmits a RACH response (RAR) message to the vehicle via the narrow beam. For example, the RAR message may be Figure 2B the RAR / Msg2 256. The base station may then use the particular narrow beam for forward link communication to complete the synchronization process as described with respect to Figure 2B After the synchronization process, the vehicle may continue to update the base station with its location via the PDN connection. Accordingly, when delivering forward link communication to the vehicle, the base station may be configured to activate a particular narrow beam that covers the location received via the PDN connection.

[0064] Figure 7 is a flowchart 700 of an example method for a base station (e.g., Figure 1 base station 145) to establish communication with a vehicle (e.g., Figure 1 vehicle 105). Specifically, the method may be performed by a base station controller of the base station (e.g., Figure 1executed by one or more processors of the base station controller 140).

[0065] Flowchart 700 begins at block 705, where a base station corresponds to a subsector of the base station and divides the sector of the base station into a plurality of subsectors. Similar to flowchart 600, the base station may make the subsectors correspond to respective sets of RA sequences.

[0066] At block 710, the base station configures the antenna array to associate the plurality of subsectors with respective narrow beams. In some embodiments, the base station associates each subsector with a gain profile pointing to the subsector. Accordingly, when the base station generates a narrow beam covering a particular subsector, the base station accesses the corresponding gain profile and configures the antenna array according to the gain profile.

[0067] At block 715, the base station broadcasts a synchronization message (e.g., synchronization signals 252 and 352 which are Figure 2B and 3B respectively) containing an identifier of the base station. For example, the synchronization message may be an SSB message containing PSS and PBCH message transmissions. In some embodiments, the base station broadcasts the synchronization message via a wide beam covering the sector of the base station.

[0068] At block 720, the base station receives a random access channel (RACH) preamble message from the vehicle. For example, the RACH preamble message may be Figure 3B 's RACH / Msg1 354. Different from flowchart 600, the RACH preamble message may contain any available RA sequence, not necessarily the RA sequence corresponding to the subsector where the vehicle is located.

[0069] At block 725, the base station sequentially activates the narrow beams associated with the plurality of subsectors. More specifically, the base station may periodically reconfigure the antenna array based on the gain profile associated with each subsector. In some embodiments, each narrow beam is activated for a sufficient duration to transmit a message to a vehicle located at the edge of the coverage area and receive a response to the message from the vehicle.

[0070] More precisely, at block 730, when activating a particular narrow beam associated with a particular subsector, the base station determines that the RA sequence contained in the RACH preamble message contains the RA sequence corresponding to the particular subsector, and broadcasts a random access response (RAR) message via the particular narrow beam. For example, the RAR message may be Figure 3BThe RAR message / Msg2356. If the vehicle is not located in the specific sub - sector covered by the active narrow beam, the vehicle will not receive the RAR message. Correspondingly, the base station will not receive a response to the RAR message. On the other hand, if the vehicle is located in the sub - sector covered by a specific narrow beam, the vehicle is configured to reply to the RAR message with an RRC connection request. It should be understood that in some embodiments, the narrow beam only supports forward - link communication. In these embodiments, the base station can implement MMSE techniques to detect reverse - link communication (including RACH preamble messages).

[0071] At block 735, the base station receives an RRC connection request from the vehicle. For example, the RRC connection request can be Figure 3B the RRC connection request / Msg3 358. It should be understood that the base station can receive the RRC connection request when the specific narrow beam is not active. For example, the base station can implement MMSE techniques during the reception period to detect the RRC connection request.

[0072] At block 740, the base station associates the vehicle with the sub - sector corresponding to the narrow beam that was active when the RAR message was transmitted. Since the vehicle can only respond to the received message, when the base station receives a response to the RAR message, the base station can determine that the vehicle is located in the sub - sector covered by the active narrow beam. The base station can then use the specific narrow beam for forward - link communication to complete the synchronization process as described with respect to Figure 3B After the synchronization process, the vehicle can continue to update the base station with its location via the PDN connection. Correspondingly, when delivering forward - link communication to the vehicle, the base station can be configured to activate the specific narrow beam covering the location received via the PDN connection.

[0073] In addition, as described with respect to Figures 4A - 4B the base station can broadcast the RAR message (via a wide beam or a narrow beam) using a single carrier or multiple carriers. In an embodiment where the base station broadcasts the RAR message using a single carrier, the base station can be configured to determine the available transmission power and broadcast the RAR message via a single carrier at the determined available transmission power. In an embodiment where the base station broadcasts the RAR message via multiple carriers, the base station can be configured to divide the available transmission power among the multiple carriers and use the corresponding divided transmission power associated with each of the multiple carriers to transmit the RAR message.

[0074] Although the above describes configuring the base station to sequentially activate narrow beams to transmit RAR messages and determine the location of the vehicle based on the reception of an RRC connection request, in other embodiments, the base station is additionally or alternatively similarly configured to sequentially activate narrow beams to transmit synchronization messages and determine the location of the vehicle based on the reception of RACH preamble messages.

[0075] Figure 8 A block diagram showing an example vehicle controller 820 that can be configured to implement various functionalities described with respect to the disclosed vehicle (e.g., Figure 1 the vehicle controller 120). The vehicle controller 820 can include, for example, one or more central processing units (CPUs) or processors 852, and one or more buses or hubs 853 that connect the processor 852 to other elements of the vehicle controller 820, such as volatile memory 854, non-volatile memory 855, a display controller 856, and an I / O controller 857. The volatile memory 854 and the non-volatile memory 855 can each include one or more non-transitory tangible computer-readable storage media, such as random access memory (RAM), read-only memory (ROM), flash memory, biometric memory, a hard disk drive, a digital versatile disc (DVD) disk drive, etc.

[0076] In one embodiment, the memory 854 and / or the memory 855 can store instructions 858 executable by the processor 852. For example, the instructions can configure the vehicle controller 820 to perform the network synchronization techniques described herein. In some embodiments, at least one of the memories 854 and 855 can additionally store base station data associated with a base station forming a communication network (e.g., a base station identifier, a base station location, a sector orientation, and / or a correspondence between a sub-sector and a RA sequence). In some embodiments, at least some of the base station data is stored at a data storage device (e.g., Figure 1 the base station database 122) external to and operatively connected to the vehicle controller 820.

[0077] The vehicle controller 820 can also include a network interface 877 controlled by the I / O control 857. The network interface 877 can be any number of antennas, transmitters, receivers, transceivers, etc., that are specifically configured to transmit or receive data at a particular frequency and / or frequency range. To this end, the instructions can include instructions that, when executed by the processor 852, cause the network interface 877 to transmit data via a local communication link and / or an external communication link. Similarly, when the network interface 877 receives data, the instructions can include instructions that cause the processor 852 to analyze and / or process the received data.

[0078] The illustrated vehicle controller 820 is only one example of a vehicle controller specifically configured for use in the vehicle 105. Other embodiments of the vehicle controller 820 can also be specifically configured for use in the vehicle 105, but other embodiments have with respect to Figure 8The additional, fewer, or alternative components shown therein, have one or more combinations of components, or have different configurations or arrangements of components. Further, Figure 8 Each of the components shown therein may be implemented in hardware, a processor executing software instructions, or a combination of hardware and a processor executing software instructions, including one or more signal processing and / or application specific integrated circuits.

[0079] Figure 9 A block diagram showing a base station controller 940 (e.g., Figure 1 base station controller 140 of Figure 1 configured to perform the functionality described herein. The base station controller 940 may include, for example, one or more central processing units (CPUs) or processors 952, and one or more buses or hubs 953 that connect the processor 952 to other elements of the base station controller 940, such as volatile memory 954, non-volatile memory 955, display controller 956, and I / O controller 957. The volatile memory 954 and non-volatile memory 955 may each include one or more non-transitory tangible computer-readable storage media, such as random access memory (RAM), read-only memory (ROM), flash memory, biometric memory, hard disk drive, digital versatile disc (DVD) disk drive, etc.

[0080] In one embodiment, the memory 954 and / or memory 955 may store instructions 958 executable by the processor 952. For example, in a base station controller specifically configured to perform the synchronization techniques described herein with respect to Figure 6 and 7 . In some embodiments, at least one of the memories 954 and 955 may additionally store data associating the vehicle with a location determined via the disclosed synchronization techniques. Further, at least one of the memories 954 and 955 may store a gain profile associated with a plurality of sub-sectors and / or a set of RA sequences (not depicted) associated with each of the sub-sectors.

[0081] Further, the base station controller 940 may include a network interface 977 controlled by the I / O control 957. The network interface 977 may be any number of antennas, transmitters, receivers, transceivers, etc., specifically configured to transmit or receive data at a particular frequency and / or frequency range. In some embodiments, the network interface 977 includes a phased antenna array configured by the I / O control 957 according to one or more gain profiles stored in the memory 954 and / or 955.

[0082] The base station controller 940 shown is only one example of a base station controller suitable for being specifically configured for use in base station 145. Other embodiments of base station controller 940 may also be specifically configured for use in base station 145, but other embodiments have additional, fewer, or alternative components relative to Figure 9 those shown in Figure 9 , have one or more combinations of components, or have different configurations or arrangements of components. Additionally,

[0083] Of course, the applications and benefits of the systems, methods, and technologies described herein are not limited to the above examples. Many other applications and benefits are possible by using the systems, methods, and technologies described herein.

[0084] In addition, when implemented, any of the methods and technologies described herein or portions thereof may be performed by executing software stored in one or more non-transitory tangible computer-readable storage media or memories (such as disks, laser disks, optical disks, semiconductor memories, biological memories, other memory devices, or other storage media) in a computer or processor's RAM or ROM, etc.

[0085] Moreover, although the detailed description above sets forth many different embodiments, it should be understood that the scope of this patent is defined by the language of the claims appended to this patent. The detailed description should be construed only as exemplary and does not describe every possible embodiment, as it would be impractical (if not impossible) to describe every possible embodiment. Many alternative embodiments can be implemented using current technology or technology developed after the filing date of this patent, and such alternative embodiments will still fall within the scope of the claims. By way of example and not limitation, the disclosure herein contemplates at least the following aspects: 1. A method for a vehicle to establish a connection with a base station, the method comprising: determining, by the one or more processors, the number of sub-sectors into which a spatial sector served by the base station is divided; causing, by the one or more processors, the sub-sectors to correspond to respective non-overlapping sets of random access sequences; receiving, from the base station, a synchronization message comprising an identifier of the base station; determining, by the one or more processors, a particular sub-sector in which the vehicle is located based on a relative position between the vehicle and the base station; identifying, based on the determined sub-sector, a particular set of random access sequences by one or more processors; and transmitting a random access channel (RACH) preamble message to the base station, wherein the RACH preamble message comprises a particular random access sequence corresponding to the particular sub-sector from within the particular set of random access sequences.

[0086] 2. The method according to the previous aspect, wherein identifying the current subsector in which the vehicle is located includes the one or more processors querying a base station database using the received identifier to determine the physical location of the base station.

[0087] 3. The method according to any combination of the previous aspects, wherein identifying the current subsector in which the vehicle is located includes the one or more processors obtaining the position of the vehicle from a positioning sensor on the vehicle; and the one or more processors comparing the physical location of the base station with the position of the vehicle.

[0088] 4. The method according to any combination of the previous aspects, wherein the synchronization message is received via a wide beam transmission.

[0089] 5. The method according to any combination of the previous aspects, further comprising, in response to transmitting the RACH preamble message, receiving a RACH response (RAR) message from the base station via a narrow beam transmission directed to the subsector corresponding to the sequence included in the RACH preamble message.

[0090] 6. The method according to any combination of the previous claims, further comprising transmitting a packet data network (PDN) connection request message to the base station; and transmitting the current position of the vehicle via the requested PDN connection.

[0091] 7. The method according to any combination of the previous aspects, wherein the current position of the vehicle corresponds to a subsector different from the particular subsector, and the method further comprises, after transmitting an RRC completion message, receiving a forward link communication from the base station via a narrow beam transmission directed to the subsector containing the current position of the vehicle.

[0092] 8. A method for a base station to establish a connection with a vehicle, the method comprising: causing subsectors of the base station to correspond to respective non-overlapping sets of random access sequences by one or more processors; broadcasting a synchronization message containing an identifier of the base station; receiving a random access channel (RACH) preamble message containing a random access sequence from the vehicle; identifying, by the one or more processors, a particular subsector of the base station corresponding to the random access sequence included in the RACH preamble message; activating, by the one or more processors, a narrow beam directed to the particular subsector; and transmitting a RACH response (RAR) message to the vehicle via the narrow beam.

[0093] 9. A method according to the previous aspect, wherein broadcasting the synchronization message includes activating, by the one or more processors, a wide beam that covers a sector of the base station; and transmitting the synchronization message via the wide beam.

[0094] 10. A method according to any combination of aspects 8 to 9, wherein broadcasting the synchronization message includes determining, by the one or more processors, a transmission power for synchronization message transmission; and transmitting the synchronization message via a single carrier using the transmission power.

[0095] 11. A method according to any combination of aspects 8 to 10, wherein transmitting the synchronization message includes determining, by the one or more processors, a transmission power for the synchronization message transmission; dividing, by the one or more processors, the transmission power among two or more carriers; and transmitting the synchronization message via the two or more carriers using a respective power associated with each of the two or more carriers.

[0096] 12. A method according to any combination of aspects 8 to 11, wherein broadcasting the synchronization message includes sequentially activating, by the one or more processors, narrow beams respectively corresponding to sub-sectors of the base station; and transmitting the synchronization message via the particular narrow beam in response to activating the particular narrow beam.

[0097] 13. A method according to any combination of aspects 8 to 12, further comprising receiving, via a packet data network (PDN) connection, a location of the vehicle from the vehicle.

[0098] 14. A method according to any combination of aspects 8 to 13, further comprising identifying, by the one or more processors, a sub-sector of the base station corresponding to the location of the vehicle; activating, by the one or more processors, a narrow beam directed to the sub-sector corresponding to the location of the vehicle; and transmitting forward link communication to the vehicle via the narrow beam directed to the sub-sector corresponding to the location of the vehicle.

[0099] 15. A method for a base station to establish a connection with a vehicle, the method comprising: dividing a sector of the base station into a plurality of sub-sectors by one or more processors; configuring an antenna array by the one or more processors to associate the plurality of sub-sectors with corresponding narrow beams; broadcasting, by the one or more processors, a synchronization message including an identifier of the base station; receiving, from the vehicle, a random access channel (RACH) preamble message including a random access (RA) sequence; sequentially activating, by the one or more processors, the narrow beams associated with the plurality of sub-sectors; when a specific narrow beam associated with a specific sub-sector is activated, determining that the RA sequence included in the RACH preamble message corresponds to the specific sub-sector, and in response to the determination, broadcasting a random access response (RAR) message via the specific narrow beam; receiving a radio resource control (RRC) connection request from the vehicle; and associating, by the one or more processors, the vehicle with the sub-sector corresponding to the narrow beam, wherein the narrow beam is in an active state when transmitting the RAR message.

[0100] 16. The method according to the previous aspect, wherein transmitting the RAR message includes determining, by the one or more processors, a transmission power for RAR message transmission; and transmitting the RAR message via a single carrier using the transmission power.

[0101] 17. The method according to any combination of aspects 15 to 16, wherein transmitting the RAR message includes determining, by the one or more processors, a transmission power for the RAR message transmission; dividing, by the one or more processors, the transmission power among two or more carriers; and transmitting the RAR message via the two or more carriers using respective powers associated with each of the two or more carriers.

[0102] 18. The method according to any combination of aspects 15 to 17, wherein broadcasting the synchronization message includes activating, by the one or more processors, a wide beam covering the sector of the base station; and transmitting the synchronization message via the wide beam.

[0103] 19. The method according to any combination of aspects 15 to 18, further comprising receiving, from the vehicle via a packet data network (PDN) connection, a location of the vehicle; determining, by the one or more processors, a sub-sector serving the location of the vehicle; and transmitting forward link communication via a narrow beam corresponding to the sub-sector serving the location of the vehicle.

Claims

1. A method for a vehicle to establish a connection with a base station, the method comprising: Determining, by one or more processors of the vehicle, the number of sub-sectors into which a spatial sector served by the base station is divided; Causing, by the one or more processors, the sub-sectors to correspond to respective non-overlapping sets of random access sequences; Receiving, from the base station, a synchronization message comprising an identifier of the base station; Determining, by the one or more processors, a specific sub-sector in which the vehicle is located based on a relative position between the vehicle and the base station by: Using, by the one or more processors, the received identifier to query a base station database to determine a physical location of the base station; Obtaining, by the one or more processors and from a positioning sensor on the vehicle, a location of the vehicle; And Comparing, by the one or more processors, the physical location of the base station with the location of the vehicle; Identifying, by one or more processors, a specific set of random access sequences based on the determined sub-sector; And Transmitting a random access channel (RACH) preamble message to the base station, wherein the RACH preamble message comprises a specific random access sequence corresponding to the specific sub-sector from within the specific set of random access sequences.

2. The method according to claim 1, wherein the synchronization message is received via a wide beam transmission.

3. The method according to claim 1 or 2, further comprising: Receiving, in response to transmitting the RACH preamble message, a RACH response (RAR) message from the base station and via a narrow beam transmission directed to the sub-sector corresponding to the sequence included in the RACH preamble message.

4. The method according to claim 1 or 2, further comprising: Transmitting a packet data network (PDN) connection request message to the base station; And Transmitting a current location of the vehicle via the requested PDN connection.

5. The method according to claim 4, wherein the current location of the vehicle corresponds to a sub-sector different from the specific sub-sector, and the method further comprises: Receiving, after transmitting an RRC completion message, a forward link communication from the base station, the forward link communication being via a narrow beam transmission directed to the sub-sector comprising the current location of the vehicle.

6. A method for a base station to establish a connection with a vehicle, the method comprising: Causing, by one or more processors of the base station, sub-sectors of the base station to correspond to respective non-overlapping sets of random access sequences; Broadcasting a synchronization message comprising an identifier of the base station, wherein broadcasting the synchronization message causes one or more processors of the vehicle to: Use the broadcast identifier to query a base station database to determine a physical location of the base station; Obtain a location of the vehicle from a positioning sensor on the vehicle; And Compare the physical location of the base station with the location of the vehicle; Receive a random access channel (RACH) preamble message containing a random access sequence identified based on the comparison from the vehicle; Identify, by the one or more processors, a specific sub-sector of the base station corresponding to the random access sequence included in the RACH preamble message; Activate, by the one or more processors, a narrow beam pointing to the specific sub-sector; And Transmit a RACH response (RAR) message to the vehicle via the narrow beam.

7. The method according to claim 6, wherein broadcasting the synchronization message includes: Activate, by the one or more processors, a wide beam covering the sector of the base station; And Transmit the synchronization message via the wide beam.

8. The method according to claim 6 or 7, wherein broadcasting the synchronization message includes: Determine, by the one or more processors, a transmission power for synchronization message transmission; And Transmit the synchronization message via a single carrier using the transmission power.

9. The method according to claim 6 or 7, wherein broadcasting the synchronization message includes: Determine, by the one or more processors, a transmission power for the synchronization message transmission; Divide, by the one or more processors, the transmission power among two or more carriers; And Transmit the synchronization message via the two or more carriers using respective powers associated with each of the two or more carriers.

10. The method according to claim 6 or 7, wherein broadcasting the synchronization message includes: Sequentially activate, by the one or more processors, narrow beams respectively corresponding to the sub-sectors of the base station; And In response to activating a specific narrow beam, transmit the synchronization message via the specific narrow beam.

11. The method according to claim 6 or 7, further comprising: Receive the position of the vehicle from the vehicle via a packet data network (PDN) connection.

12. The method according to claim 11, further comprising: Identify, by the one or more processors, a sub-sector of the base station corresponding to the position of the vehicle; Activate, by the one or more processors, a narrow beam pointing to the sub-sector corresponding to the position of the vehicle; And Transmit forward link communication to the vehicle via the narrow beam pointing to the sub-sector corresponding to the position of the vehicle.

13. A method for a base station to establish a connection with a vehicle, the method comprising: Divide, by one or more processors of the base station, the sector of the base station into a plurality of sub-sectors; Configure, by the one or more processors, an antenna array to associate the plurality of sub-sectors with respective narrow beams; Broadcast, by the one or more processors, a synchronization message containing an identifier of the base station, wherein broadcasting the synchronization message causes one or more processors of the vehicle to: Query a base station database using the broadcast identifier to determine the physical location of the base station; Obtain the position of the vehicle from a positioning sensor on the vehicle; And Compare the physical location of the base station with the position of the vehicle; Receive a random access channel (RACH) preamble message from the vehicle, the RACH preamble message including a random access (RA) sequence identified based on the comparison; Sequentially activate, by the one or more processors, the narrow beams associated with the plurality of subsectors; When a particular narrow beam associated with a particular subsector is activated: Determine that the RA sequence included in the RACH preamble message corresponds to the particular subsector, and in response to the determination, broadcast a random access response (RAR) message via the particular narrow beam; Receive a radio resource control (RRC) connection request from the vehicle; And Associate, by the one or more processors, the vehicle with the subsector corresponding to the narrow beam, the narrow beam being active when the RAR message is transmitted.

14. The method according to claim 13, wherein transmitting the RAR message comprises: Determine, by the one or more processors, a transmission power for RAR message transmission; And Transmit the RAR message via a single carrier using the transmission power.

15. The method according to claim 13, wherein transmitting the RAR message comprises: Determine, by the one or more processors, a transmission power for the RAR message transmission; Divide, by the one or more processors, the transmission power among two or more carriers; And Transmit the RAR message via the two or more carriers using a respective power associated with each of the two or more carriers.

16. The method according to any one of claims 13 to 15, wherein broadcasting the synchronization message comprises: Activate, by the one or more processors, a wide beam covering the sector of the base station; And Transmit the synchronization message via the wide beam.

17. The method according to any one of claims 13 to 15, further comprising: Receive, via a packet data network (PDN) connection, the location of the vehicle from the vehicle; Determine, by the one or more processors, a subsector serving the location of the vehicle; And Transmit forward link communication via a narrow beam corresponding to the subsector serving the location of the vehicle.

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