JP4260593B2 - Information distribution control station apparatus and program - Google Patents

Description

  The present invention relates to a technique for distributing information to a moving body that moves between communication areas of a plurality of base stations in a wireless communication system.

  It has been conventionally performed to distribute information to mobile objects such as mobile phones and mobile terminals. A communication system such as a mobile phone is a form in which a plurality of base stations cover a communication area evenly and uniformly. However, as the communication speed increases in the future, the area covered by one base station becomes smaller, and a communication system in which a plurality of base stations cover an area (hereinafter referred to as a communication spot) in a spot rather than a continuous manner. It is conceivable that many will be adopted.

  For example, when information is distributed to a car traveling on a highway using such a communication system, not all information can be distributed in one communication spot, so the following method can be used. Possible (see Patent Documents 1 and 2).

  (1) From the information received at each communication spot, request the shortage information at the next communication spot, (2) Based on the speed at the time of requesting information, it can be received when moving the communication spot at that speed For example, the information is divided into sizes that can be transmitted in a shorter time than a certain time, and the divided information is arranged in each base station.

In addition, there are technologies described in Non-Patent Documents 1 and 2 as technologies related to information distribution.
JP 2000-253449 A JP 2000-33285 A Kazunari Kumagai, Hiroyoshi Tonami, Shinya Nogami, “Proposal and Evaluation of Data Transmission Method to High-Speed Mobiles Using Spot Type Communication”, IEICE Technical, ITS2002-2 (2002-5) Hiroshi Yoshioka, Masashi Nakatsugawa, Shuji Kubota, "An Effective Data Transmission Control Method for Mobile Terminals in Spot Communication Systems", IEICE Trans. Fundamentals, Vol.E83-A, No.7, July 2000

  However, in the method (1), the exchange of control information with a server that distributes information is complicated, and there is a risk that information distribution to a mobile body that passes through intermittently arranged communication spots at high speed cannot be performed sufficiently. There is.

  Further, in the method (1), when the information block reception capability of the mobile unit (that is, the amount of information that can be received in a certain time) is different, the mobile unit with low reception capability may not be able to receive all the information blocks. .

  In the method (2), since the speed of the moving body is not always constant, there is a problem that it cannot follow when the speed becomes higher than the speed assumed for information arrangement. As a countermeasure, it is conceivable that the speed of the moving body is transmitted for each communication spot and the server divides and distributes based on the speed, but the control becomes complicated as in (1). It is also conceivable that information of an amount corresponding to a mobile body that moves at a very high speed or a mobile body that has a low information block reception capability is arranged in the base station. However, in this case, in order to reduce the amount of information that can be distributed by one base station, the number of base stations required for distributing the same amount of content increases, and the mobile body that receives the information moves at a speed slower than the set speed. Even if the mobile station has higher reception capability, the base station has data that can be distributed even though it can still receive information while passing through one base station area. Therefore, it is impossible to receive all information until it passes through the base station determined from the set speed and the reception capability. That is, there is a problem that it takes a long time to receive all the information in a moving body with a lower speed or a higher receiving ability.

  The present invention has been made in view of the above points. In a wireless communication system that covers an area in a spot manner, the moving speed of the moving body can be controlled without complicated control between the moving body and the base station / control station. Accordingly, it is an object of the present invention to provide a technology that makes it possible to efficiently distribute information to a moving body.

  An object of the present invention is to provide a plurality of base station devices and a control station device connected thereto, and to distribute distribution information held in the control station device to a moving body that moves between communication areas of the base station device. The control station apparatus in a wireless communication system that divides the information block into a predetermined size and distributes the information block via the base station apparatus, wherein the distribution information storage means for storing the distribution information, and the mobile unit Initial block number holding means for calculating and holding the number of initial information blocks N1 that the base station apparatus can distribute to the mobile body while moving in the communication area of the base station apparatus, and information to be distributed The variation value holding means for holding the variation value n of the number of blocks, the minimum block number holding means for holding the minimum number of information blocks Nmin distributed by the base station apparatus, and the distribution information storage means A first information block is allocated to each base station apparatus in the traveling direction of the mobile body as an information block for distribution to the mobile body, by the initial information block number N1 held in the initial block number holding means. And the number of information blocks obtained by subtracting the variation value n held in the variation value holding means from the initial information block number N1 as the update information block number N2 (where (N1-n ) <Nmin, if N2 = Nmin), the distribution order from each base station apparatus to the mobile unit from the update block number holding means to be held and the distribution information block already assigned to the base station apparatus is An information block that is not within the update block number N2 is extracted as a retransmission information block, and the distribution information block that is less than the update block number N2 is extracted. To the base station apparatus to which the distribution information block is unallocated and forward of the moving body in the traveling direction so that the number of information blocks is equal to or less than the update block number N2. Second block allocating means for allocating a block as a distribution information block, and when the number of updated blocks N2 of the second block allocating means exceeds the minimum number of information blocks Nmin, the updated block number holding means The number of information blocks obtained by subtracting the variation value n from the number of update information blocks N2 held in is set as a new number of update information blocks N2 (however, if (N2-n) <Nmin, N2 = Nmin), the update block number holding unit is updated, and the processing by the second block allocation unit is changed to the update information. A control station apparatus comprising: a control unit that repeats until the number of locks N2 is equal to or less than the minimum number of information blocks Nmin; and a unit that distributes information blocks allocated to the base station apparatus to each base station apparatus it can.

  According to the present invention, an information block that is predicted to be unable to be received by the speed and information reception capability of a mobile unit is overlapped with a base station that is further forward in the traveling direction and is distributed from one base station. Since the process of deploying by sequentially decreasing the number is repeated, the mobile unit can move at any speed between the initial expected speed and the assumed maximum speed, or the mobile unit can receive information as the information receiving capacity. Regardless of the assumed minimum information reception capability, all information blocks can be efficiently received according to the moving speed of the mobile body and the information reception capability.

  For example, for the speed change of the moving body, the initial information block number N1 is obtained as the minimum speed assumed as the “predetermined speed”, and the “minimum information block number Nmin” is obtained based on the maximum speed assumed by the mobile body. The “variation value n” may be set as a value corresponding to the speed obtained by dividing the interval between the minimum speed and the maximum speed into several.

  In the above, an information block is added and assigned to a base station to which an information block less than the number of update information blocks is assigned. However, after obtaining the number of update information blocks N2, an information block is assigned. At this time, the allocation may be performed from the base station ahead of the traveling direction rather than the allocation of the information block. This simplifies management of the assigned base station, and information can be distributed immediately after assignment to the base station base station.

  Further, the initial information block number N1 can be determined according to the traffic situation (the degree of traffic jam, etc.) of the road where the base station is arranged.

  Further, the minimum number of information blocks Nmin can be determined in consideration of the legal maximum speed of the road where the base station is installed.

  Moreover, said subject can also be solved by the computer program which makes a computer perform each process step in each process means of the control station apparatus of this invention.

  According to the present invention, efficient information distribution with reduced redundancy can be performed without requiring a complicated sequence between the mobile unit and the control station. In addition, even when the actual speed of the moving body fluctuates between the initial expected speed and the assumed maximum speed, it is possible to efficiently distribute all the information blocks according to the moving speed of the moving body. In other words, there is an effect that the mobile object moves faster than the initial expected speed, and it is possible to receive information without duplication, and for moving slower than the assumed maximum speed, there is information in the case of the assumed maximum speed. There is an effect that information can be received through a number of base stations smaller than the number of base stations that must pass through to receive the signal.

  Furthermore, according to the present invention, even when mobile units having different information reception capabilities are mixed, all information blocks can be received by passing the number of base stations according to the reception capability.

  In addition, not only when delivering by request from individual mobile bodies, but also when broadcasting contents such as news, traffic information, video, etc. from a predetermined plurality of base stations, mobile bodies having various speeds and communication capabilities On the other hand, information can be distributed from a required plurality of base stations according to each state.

  In addition, by setting the minimum number of information blocks corresponding to the legal maximum speed of the road where the base station is installed, the mobile object that is to receive the information will comply with the legal speed, and traffic regulations will be applied. It can also help promote compliance.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a system configuration in an embodiment of the present invention. The system according to the embodiment of the present invention has a configuration in which a plurality of base stations arranged on a road and a control station 4 are connected by a network 5, and information transmitted from the control station 4 is transmitted via each base station. And distributed to terminals mounted on automobiles traveling on the road. The control station 4 is connected to a distribution content providing device 7, a traffic condition information providing device 8 that provides information related to traffic conditions such as road congestion, and the like via a network 6. In this specification, a device such as a terminal that transmits and receives information while moving is referred to as a moving body.

  The wireless communication system in the system shown in FIG. 1 is a system in which each base station forms a narrow cell that covers an area in a spot manner. For example, the communication system conforms to DSRC (Dedicated Short Range Communications) and a wireless LAN standard. It is a compliant communication method. Accordingly, each base station in the present embodiment has a function for performing wireless communication with a mobile unit according to the wireless communication method. Moreover, each base station is intermittently arrange | positioned on a road, and the communication area of each communication spot does not overlap.

  FIG. 2 shows a configuration example of the base station. As shown in FIG. 2, the base station transmits an antenna 10 for transmitting / receiving radio waves for communication with a mobile unit, a transmitter / receiver 11 for realizing communication compliant with DSRC, etc., and transmits to a mobile unit received from a control station. Control unit 13 for controlling data to be transmitted, data transmission / reception, data necessary for control such as communication with a mobile unit or a control station, and the like, and control unit 13 for transmission / reception unit 11 and storage unit 12 And an interface control unit 14 for performing data transmission / reception with the control station 4.

  The control station 4 is a computer having a communication function, which is equipped with a program for acquiring transmission target information in response to a request from a mobile body or an information distribution apparatus, and performing processing for dividing and acquiring the information to be allocated to each base station. is there. That is, the control station 4 has a storage device such as a CPU, a memory, and a hard disk, and reads a program for performing processing according to the present invention from the memory and executes it by the CPU.

  FIG. 3 shows an example of functional blocks of the control station. The control station 4 includes a distribution information accumulation unit 4-1 that accumulates distribution information for distribution to a mobile body via a base station, and a control information holding unit that stores various control information for allocating information to each base station. 4-2, control for performing control such as allocation of information blocks to be distributed to each base station based on information held in the control information holding unit 4-2 and position information of the moving body, preparation of information to be distributed, etc. Unit 4-3, base station interface unit 4-4 for transmitting / receiving control information and distribution information to / from each base station, acquisition of distribution information not present in the control station 4, acquisition of road traffic information where the base station is located, etc. And an external network interface unit 4-5 for exchanging information.

  The control information holding unit 4-2 controls the information distribution control such as the number of initial blocks N1, the variation value n, the minimum number of blocks Nmin, the number of updated blocks N2 and the like, the road under control, the type of requested terminal, the information block size of distribution information, etc. It memorizes according to the pattern that affects. The update block number N2 is updated according to the distribution information allocation process to each base station. In addition, the initial block number N1, variation value n, and minimum block number Nmin are stored in the control station, or obtained from the external NW interface unit 4-5. Pre-set conditions based on traffic information, legal speed set on the road, communication capability of the target mobile device, communication capability of the base station (communication speed, communication area size, etc.), configuration of the content to be distributed, etc. Determined by

  The control unit 4-3 receives an information distribution request from the mobile body via the base station, reads the initial block number N1 from the control information holding unit 4-2, and moves the mobile body according to the position of the mobile body. A first block allocating unit 4-31 that identifies a base station ahead in the traveling direction and allocates N1 information blocks to each identified base station, and then holds the initial block number N1 and next control information An update block number N2 is obtained from the variation value n read from the unit 4-2, and the update block number holding unit 4-24 corresponding to the read initial block number is stored in the control information holding unit 4-2. In addition to recording, information blocks already assigned to the base station are extracted as redistribution information blocks whose order of transmission to the mobile body is not up to the N2th, and are transmitted to the base station ahead of the mobile body traveling direction. N2 at a time The second block allocation unit 4-32 for allocating an information block, including a block allocation control unit 4-35 for controlling to repeat until the processing of the second block allocation unit 4-32 N2 is equal to or less than Nmin.

  The base station interface unit 4-4 performs communication processing with the base station, such as receiving information distribution requests from the base stations and the mobile unit, and sending information distributed to the mobile unit to the base station.

  In the external network interface unit 4-5, a site storing information to be distributed to the mobile unit, a traffic status (average speed, etc.) management site of the road where the base station is installed, and information provided from the control station to the mobile unit (Content title, usage conditions) Communication processing with an external network for exchanging necessary information from a public relations site or the like.

  Note that the transmission target information is map data, still images, videos, contents such as music, mail, programs, and the like. In addition, the mobile body mounted on the automobile is, for example, a mobile phone, a mobile terminal, a PC, and the like, stores a function for transmitting and receiving information conforming to the wireless communication method in this system, and stores the received information in a predetermined order. It has a function to display / execute in combination.

  Next, the outline of the operation of the system shown in FIG. 1 will be described with reference to the sequence diagram of FIG. In the following, a case where information is distributed based on a request from a mobile unit will be described as an example. However, the present invention is also applied to a case where predetermined information is broadcast from a plurality of predetermined base stations to a mobile unit moving in the area. Easy to apply.

  First, the mobile unit makes an information distribution request to the control station (step 1). The control station divides the requested information according to a predetermined assumed speed of the mobile unit, and assigns the divided information blocks according to a predetermined rule to a plurality of base stations located in the traveling direction of the mobile unit (step 2). The information block is transmitted to the base station (step 3). Each time the mobile unit enters the communication area of the base station after making an information distribution request, it requests the base station for information (step 4). The base station that has received the request transmits the information block held corresponding to the mobile body to the mobile body (step 5). The mobile body determines whether or not all the information to be distributed has been received, and if all the information has been received, combines the received information blocks to construct the original information (step 6). In the present embodiment, in step 2 above, the information divided by assuming the speed of the moving body is assigned to the base station, and only the same information as the information that cannot be received when traveling at the speed or higher is forwarded. Reassign to the base station. This enables efficient information distribution.

  Next, a series of processes will be described in more detail with reference to the flowchart of FIG. In the following example, information to be transmitted is referred to as content.

  First, the mobile body transmits a content information request including a mobile body ID, position information, moving direction, speed, and content identification information for uniquely identifying the mobile body to the control station (step 11). . Note that speed need not necessarily be included. Further, when the target road has only one moving direction, it is not necessary to include the moving direction. The location information can be transmitted as, for example, the ID of a base station that has covered the mobile unit at the present time or the latest time point, or can be transmitted as GPS information if the mobile unit has a GPS function. Also, the moving direction and speed can be calculated and sent by the moving body itself, for example, from the time for moving between areas of the base station.

  The control station acquires the requested content from a database or the like based on the identification information included in the content information request received from the mobile body. The database may be a database held by the control station or a database of a server connected to the Internet or the like. Then, the requested content is divided into predetermined block sizes, and a distribution information group is generated (step 12).

  This block size assumes the maximum speed of an automobile traveling on the road (assumed maximum speed), and is defined as the amount of information that one base station in the communication system can deliver to the mobile body at the assumed maximum speed. And This amount of information is determined from the above assumed maximum speed, the size of the communicable range of one base station in the communication system, and the communication speed at which information is transmitted to the mobile body. Therefore, if the maximum speed is the same, the block size is determined depending on the specifications of the communication system (the size of the communicable range of the base station and the communication speed). Further, the block size may be determined in consideration of the data reception capability on the mobile unit side.

  Further, the control station assigns an ID for identifying each information block to each information block of the distribution information group generated by dividing the content. In addition, in order to make it possible to determine whether the mobile body has received all the information, the first information block of the distribution information group includes information on the total number of information blocks in the distribution information group. Note that information on the total number of information blocks can be included in an arbitrary information block instead of the first information block.

  Next, the control station sets an initial value (initial predicted speed) of the predicted speed of the moving body (step 13). As the initial value of the expected speed, a fixed value determined for each road, or a moving speed at the time of information request from a moving body, or a moving speed at the time of information request and a slower speed of a fixed value determined for each road. Etc. can be used. If there is a factor (such as traffic jam) that can be slower than these speeds, a speed slower than these speeds is set as the initial value of the expected speed. Note that the fixed value determined for each road is, for example, a value determined from a statistical value, and may be held by the control station for each road, or may be acquired from another database or the like via a network.

  Then, when the moving body moves from the head of the distribution information group at the expected speed, the control station extracts information blocks for each information block that can be received from one base station, and moves. Along with the body ID, each information block is arranged in each base station arranged in the traveling direction of the mobile body (step 14). However, when extracting information blocks for each number of information blocks, if the number of remaining information blocks is less than the number of information blocks, all remaining information blocks are arranged in the base station. The reason why the mobile body IDs are arranged together is to determine which mobile body the information block held in each base station corresponds to.

  Note that “arrangement” here refers to logically allocating an information block to a base station within the control station and actually transmitting the allocated information block to the base station. The base station temporarily stores the information block and mobile ID received from the control station.

  When the mobile object moves at the expected speed, the number of information blocks that the mobile object can receive from one base station is the information amount of one information block, the size of the communicable range of the base station, the communication speed, And the expected speed of the moving body.

  Following the processing of step 14, the control station obtains a new predicted speed using the following equation from the assumed maximum speed and the preset number of repetitions (step 15). The old predicted speed in the following formula is the previous predicted speed.

Expected speed = old expected speed + (assumed maximum speed-initial expected speed) / number of repetitions During the repetition, the control station ends the arrangement process when the expected speed exceeds the estimated maximum speed (YES in step 16). To do.

  When the expected speed does not exceed the assumed maximum speed (NO in step 16), the control station calculates the above-described equation using the above-mentioned equation on the assumption of the arrangement state of the information block to each base station performed so far. If it is assumed that the vehicle has traveled at a new predicted speed, the same information block as the information block that cannot be received by the mobile unit is extracted at each base station, and this is used as a new distribution information group (step 17). Then, the information block is arranged (step 18). Note that the number of information blocks that cannot be received can be obtained by subtracting the number of information blocks that can be received at the new expected speed from the number of information blocks that can be received at the previous expected speed.

  The control station repeats the processing from step 15 to step 18. In step 14, each information block in the new distribution information group is transferred to a base station that is less than the number of information blocks per base station corresponding to the new predicted speed, so that the number of information blocks is the same. It is arranged in each base station ahead of the base station in which information blocks of the number of information blocks or more are already arranged.

  It should be noted that the process of logically allocating information blocks to the base station within the control station may be performed by repeating Step 14 and Steps 15 to 18. In this case, after all the assignments are completed (after the check in Step 16 becomes Yes), the information block is transmitted to each base station according to the assignments.

  The arrangement of information in each base station is completed before the mobile body enters the communicable range of the first base station holding the information block. That is, using the position at the time of information request of the mobile object, the speed of the mobile object or the initial expected speed, and the time from when the control station receives the information request until the transmission of the information block to each base station is completed, The first information block may be arranged at a base station separated by ((speed of mobile object) × (time until transmission of information block)) from the position at the time of request.

  When the mobile unit enters the communicable range of the base station after transmitting the content information request, the mobile unit transmits an information request including its mobile unit ID to the base station (step 19). Note that whether or not the mobile unit has entered the communicable range of the base station is determined by, for example, the base station periodically transmitting predetermined information and whether or not the mobile unit itself can receive the information. .

  When the information block corresponding to the mobile body ID received from the mobile body is stored, the base station distributes the information block to the mobile body and releases the stored information block. The mobile receives the information block (step 20).

  The mobile unit determines whether or not all information blocks have been received from the ID for identifying the information block included in the information block received from the base station and the total number of information blocks included in the first information block (step 21). ). If all the information blocks have not been received, repeat the processing of steps 19 and 20, and when all the information blocks have been received, reconstruct the original content based on the ID identifying the information block included in the information block Then, the reception process ends.

  It should be noted that the mobile unit does not come to the base station where the information is located or the mobile unit has made an information request because the receiver has failed or the mobile unit has gone to a completely different road. Since it is assumed not to be performed, an effective period may be set for the information arranged in the base station, and information past the effective period may be deleted. As a result, the resources of the base station can be prevented from overflowing.

  Alternatively, the mobile unit may notify the control station that the reception process has been completed, and then the information block arranged in the base station by the control station may be deleted. The mobile station may detect that the mobile station has passed through the last base station to which information is distributed, and then delete the information block arranged in the base station.

  Next, the arrangement of information blocks in the base station will be described more specifically with reference to FIG.

  First, as an assumption, the initial value of the expected speed: v0 (Km / h), the number of repetitions: 3, the assumed maximum speed: v3 (Km / h), and each repetition obtained from the above equation in step 15 The expected speed at this time is initial: v0 (Km / h), first time: v1 (Km / h), second time: v2 (Km / h), third time: v3 (Km / h). Also, the number of distribution information blocks f (v) that can be received by the mobile unit at each speed v at the base station is f (v0) = 4, f (v1) = 3, f (v2) = 2, f (V3) = 1.

  Further, it is assumed that the mobile unit has requested a content 16 times larger than the block size, and the mobile unit proceeds to the base station where the mobile unit is to be moved and the information block is to be arranged. IDs are assigned in the order of base station 1, base station 2 (BS2),. In FIG. 6, the base station is described as BS.

  The control station that has received the request from the mobile object divides the acquired content into 16 information blocks, and sets the IDs of the information blocks to 1-16. That is, the distribution information group is 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16. The control station associates each ID with the information block and holds it in a memory or the like.

  Next, an information block is allocated to each base station based on the initial speed v0. Since the number f (v0) of distributable information blocks at each base station at the speed v0 = 4, four information blocks from the beginning of the distribution information group to each base station as shown in (1) of FIG. Deploy. More specifically, the control station associates the base station ID with the information block ID assigned to the base station, stores the information in the memory, reads the contents of the memory, and sends the read base station ID to the base station. Then, an actual information block corresponding to the read information block ID is extracted and transmitted. That is, FIG. 6 can be considered to show the information blocks actually held in the base station and the contents of the memory in the control station. The specific processing contents are the same in the following processing.

  Next, the same information block as the information block that cannot be received by the base stations 1 to 4 when the next predicted speed v1 is set is extracted from the 16 information blocks. Since the number f (v1) = 3 of distributable information blocks at the base station at the speed v1, information blocks that cannot be received in the arrangement shown in (1) of FIG. 6 are as shown by the underline in (2). Since the base station 1 is 4, the base station 2 is 8, the base station 3 is 12, and the base station 4 is 16, the new distribution information group (retransmission information block) is 4, 8, 12, and 16.

  Then, the extracted new distribution information group is arranged by the number of information blocks that can be received from the base station 5 when traveling at the speed v1. That is, as shown in (2) of FIG. 6, since the base station 4 has already been arranged, three base stations 5 are arranged. However, in this case, since there are four in total, only one information block is arranged in the base station 6. Therefore, when information that has already been arranged is shown in parentheses (), the information is base station 1: (1, 2, 3, 4), base station 2: (5, 6, 7, 8), base station 3: (9, 10, 11, 12), base station 4: (13, 14, 15, 16), base stations 5: 4, 8, 12, and base station 6:16.

  Subsequently, an information block that cannot be received when the next predicted speed v2 is set is extracted. Since the number of distributable information blocks f (v2) = 2 at the base station at speed v2, information that cannot be received in the arrangement shown in (2) of FIG. 6 is underlined in (3) of FIG. The base station 1 is 3, 4, the base station 2 is 7, 8, the base station 3 is 11, 12, the base station 4 is 15, 16, and the base station 5 is 12. However, since information that could not be received by the base station 1, 4 that cannot be received by the base station 2, and 16 that cannot be received by the base station 4 can be received by the base stations 5 and 6, respectively. , 7, 11, 12, 15 and these become a new distribution information group (retransmission information block).

  The extracted new distribution information group is arranged as shown in (3) of FIG. That is, since only one information block is arranged in the last base station 6, one information block is arranged in the base station 6 and two information blocks are arranged in the subsequent base stations.

  Subsequently, an information block that cannot be received when the next predicted speed v3 is set is extracted. Since the number of distributable information blocks at the base station at the speed v3 is f (v3) = 1, the information that cannot be received in (3) in FIG. 6 is the number underlined in (4) in FIG. The base station 1 is 2, 3, 4, the base station 2 is 6, 7, 8, the base station 3 is 10, 11, 12, the base station 4 is 14, 15, 16, the base station 5 is 8, 12, Station 6 is 3, base station 7 is 11, and base station 8 is 15. However, base station 5, 4, 7 and 8 can receive 4 points which cannot be received by base station 4, 16 which cannot be received by base station 2, 7 which cannot be received by base station 2, and 12 which cannot be received by base station 3. The information that cannot be finally received is 2, 3, 6, 8, 10, 11, 14, and 15, and these are a new distribution information group (retransmission information block). Then, the extracted new distribution information group is arranged as shown in (4) of FIG. That is, one piece of information is arranged from the base station 9 one by one.

  In the above example, the number of distribution information blocks that can be received by the mobile unit at one base station at each speed decreases by one. In other words, by setting the number of repetitions so as to decrease by 1 in this way, the mobile unit can move to each base station regardless of the actual speed of the automobile between the initial expected speed and the assumed maximum speed. Can receive the maximum number of information blocks without duplication. However, reception is performed in units of information blocks.

  For example, in the above example, if the number of repetitions is 1, after four information blocks are first arranged in the base station, the mobile object can be received by one base station in the next arrangement process. Since the number of distribution information blocks is 1, a total of 12 last three information blocks in the base stations 1 to 4 are arranged in the base stations 5 to 16. In this case, when the moving body travels at the assumed maximum speed, there is no difference from the case where the number of repetitions is 3, but when the moving body is slower than the maximum assumed speed, it is compared with the case where the number of repetitions is 3 times. Thus, it takes a long time to receive all information. From this, when the block size is optimally set with respect to the moving speed and speed width of the mobile object, the number of distribution information blocks that can be received by the mobile object in one base station is one for each repetition of the arrangement. The number of repetitions is preferably set so as to decrease.

  In the above example, the number of repetitions is set first, and the expected speed is sequentially increased according to the number of times, but the speed increase range from the initial expected speed is determined, and the expected speed becomes the assumed maximum speed. Up to the initial predicted speed, the information block may be arranged by sequentially increasing the predicted speed for each speed increase range.

  Furthermore, the number of blocks that can be distributed by one base station is set, and until the number of blocks that can be distributed by one base station becomes 1, the number of blocks is sequentially decreased from the number of blocks that can be distributed by one base station at the initial expected speed. The information blocks may be arranged. Here, the width for reducing the number of blocks is not necessarily one.

  FIG. 7 shows the allocation result to each base station when the number of initial blocks is N1 = 15, the difference value is n = 4, and the minimum number of blocks is Nmin = 6 for 40 information blocks. The first base station is assigned information blocks from 1 to 15. The third base station is assigned 31 to 40 blocks. Next, the number of update blocks N21 = N1-n = 15-4 = 11 is obtained, and information that is not assigned to be distributed within eleventh in each base station (base stations 1, 2, and 3 in this example) Blocks 12, 13, 14, 15 and 27, 28, 29, 30 are 1 block to base station 3 already assigned 10 blocks (11 blocks are transmitted per base station), and the remaining 7 blocks Assign to base station 4. Next, for the base stations 1 to 4 to which information blocks have already been assigned, information blocks 8, 9, 10, 11, 12, and 23 that are not assigned to be transmitted within N22 = seventh. , 24, 25, 26, 38, 39, and 40 are allocated to the base stations 5 and 6, respectively. Next, for the base stations 1 to 6 to which information blocks have already been assigned, information blocks that are not assigned to be distributed within N23 = 3rd are extracted, and similarly assigned to the base stations 7 to 14.

  Thereby, for example, a mobile that moves at a relatively low speed can receive all information by passing through the base stations 1 to 3. In addition, a moving body moving at a relatively medium speed can receive all information by passing through 1 to 6 base stations. Further, a mobile moving at high speed can receive information blocks that cannot be received by the base stations 7 to 14 although there are information blocks that cannot be received by the base stations 1 to 6.

  Although the above has been described with respect to changes in the speed of the moving body, N1, n, and Nmin are similarly adjusted when the receiving capacity of the moving body is different and the combination of the receiving capacity and speed of the moving body is different. Can be adapted.

  In this way, depending on the speed and reception capability of the mobile unit, low-speed and high-reception capability mobile units pass through a small number of base stations, and high-speed and low reception capability mobile units depend on the base station and mobile unit communication capabilities. Necessary information can be received by passing the number of base stations.

  FIG. 8 is a diagram showing block allocation in a case where allocation is made to a base station to which an information block has not already been allocated when the update block count N2 is obtained and allocated so that the number of blocks per base station is 11 or less. is there. That is, in the case of FIG. 7, the block 12 is allocated to the base station 3, but in the case of FIG. 8, the base station 3 that can be allocated by adding the information block is not allocated by adding the information block. The allocation starts from 4.

  In the case of FIG. 7, there is a feature that information can be distributed with fewer base stations. On the other hand, in the case of FIG. 8, since the allocation of the information block does not occur in addition to the allocated base station, the control can be simplified, and the information can be immediately distributed to the allocated base station. There are features.

  Now, an example of a processing method for performing placement while reducing the number of blocks that can be distributed by one base station one by one will be described. The processing of the control station in this case will be described using the flowchart of FIG.

  First, the control station that has received the information distribution request from the mobile body divides the content into a plurality of information blocks (step 101). This division method is the same as in the above example. Next, the number N of information blocks that can be distributed from one base station to a moving body assumed to move at a predetermined expected speed is obtained, and information blocks are arranged in each base station for every N (step 102). In this case, the number of information blocks of the last base station that arranges information blocks may be less than N.

  Next, the variable m = N is set (step 103). Then, the same information block as the m-th information block of each base station in which m or more information blocks are arranged is extracted, and the extracted information block is forward of the base station in which m information blocks are arranged. The base station is arranged so that the number of information blocks is (m−1). Note that the number of information blocks of the last base station may be less than (m−1) (step 105).

  Next, m = m−1 is set (step 106). If m is 1 (YES in step 107), the process is terminated. If m is not 1 (NO in step 107), the processing from step 104 to step 107 is repeated.

  Such processing can also arrange information as shown in FIG.

  Next, processing for determining the initial expected speed and the assumed maximum speed and performing block arrangement while increasing the speed by a predetermined speed width from the initial predicted speed will be described. FIG. 10 shows a flowchart of processing of the control station in this case.

  First, the control station that has received the information distribution request from the mobile unit divides the content into a plurality of information blocks (step 201). This division method is the same as in the above example. Next, the number N1 of information blocks that can be distributed from one base station to a moving body assumed to move at a predetermined initial predicted speed (V1) is obtained, and information blocks are arranged in each base station for every N1 (step 202). ). In this case, the number of information blocks of the last base station that arranges information blocks may be less than N1.

  Next, a speed obtained by adding a predetermined speed width (v) to the initial expected speed is set as V2 (step 203), and the number N2 of information blocks that can be distributed from one base station to a moving body assumed to move at V2 is obtained ( Step 204). Then, when V2 is equal to or less than the assumed maximum speed and the number of information blocks N2 is 1 or more, the following block arrangement is performed (Yes in step 205).

  A base block to which an information block less than N2 is assigned to an information block distributed after the (N2 + 1) th in each base station to which an information block has been assigned and which is not distributed within the N2th It arrange | positions so that the number of information blocks may become N2 with respect to a station and the base station ahead of it (step 206). That is, for example, when the information block of 5 is an information block to be arranged in the forward base station, for the forward base station in which the information block of 5 is already arranged as the N2th and lower information blocks, The information block is not arranged, and the information block of 5 is arranged in a base station after the base station. For example, when an information block of 6 is included in the (N2 + 1) th and subsequent information blocks in a certain base station and another base station, only one 6 information block is arranged in the front base station. To do.

  In this case, the number of information blocks of the last base station that arranges information blocks may be less than N2.

  Next, the speed obtained by adding the speed width (v) to V2 is set to V2 again (step 207), and the above processing is repeated.

  The initial predicted speed (V1) is the movement that has passed through the communication area of the base station in the time interval between the time when the control station starts allocating information blocks and the time that is a predetermined time after that time. It can be determined using the average speed of the body. For example, a speed obtained by subtracting a predetermined speed from the average speed can be set as the initial expected speed (V1). Further, a predetermined speed range (v) that is sequentially increased from the initial expected speed (V1) can also be determined from the average speed. For example, when the average speed is larger than a predetermined speed, the speed width (v) can be reduced.

  In the above processing, instead of increasing the speed by v, the number of blocks that can be distributed by one base station is sequentially decreased, and the arrangement may be repeated until immediately before the number of blocks becomes less than one.

  In this embodiment, an example is described in which information is distributed to a mobile body mounted on an automobile or the like. However, in the present invention, a distribution destination for distributing information is a mobile body mounted on an automobile or the like as long as it moves. It is not limited to.

  Also, in this embodiment, the case where specific information for a mobile body is delivered in response to a request from a mobile body is taken as an example, but the same information is sent to an unspecified number of mobile bodies as in broadcast. The information distribution method of the present invention can also be applied when distributing. In this case, for example, broadcast information such as news video is arranged in each base station in a predetermined section according to the arrangement method of the present invention, and the mobile body receives the broadcast information when entering the section.

  The present invention is not limited to the above-described embodiments, and various modifications and applications can be made within the scope of the claims.

It is a figure which shows the system configuration | structure in embodiment of this invention. It is a figure which shows the structural example of the base station in embodiment of this invention. It is a functional block diagram of a control station in an embodiment of the present invention. It is a sequence diagram for demonstrating the operation | movement outline | summary of the system in embodiment of this invention. It is a flowchart for demonstrating in detail the operation | movement of the system in embodiment of this invention. It is a figure for demonstrating concretely the arrangement | positioning method of the information block to a base station. It is a figure which shows the example of the allocation result to each base station of 40 information blocks. It is a figure which shows the other example of the allocation result to each base station of 40 information blocks. It is a flowchart which shows the other processing method for arrangement | positioning of the information block to the base station in a control station. It is a flowchart which shows the further another processing method for arrangement | positioning of the information block to the base station in a control station.

Explanation of symbols

1-3 Base station 4 Control station 4-1 Distribution information storage unit 4-2 Control information holding unit 4-3 Control unit 4-31 First block allocation unit 4-32 Second block allocation unit 4-33 Block allocation control unit 4-4 Base Station Interface Unit 4-5 External Network Interface Units 5 and 6 Network 7 Distribution Content Providing Device 8 Traffic Condition Information Providing Device 10 Antenna 11 Transmission / Reception Unit 12 Storage Unit 13 Control Unit 14 Control Station Interface Unit

Claims (9)

A plurality of base station devices and a control station device connected thereto, and distribution information held in the control station device is transmitted to a mobile body that moves between communication areas of the base station device with a predetermined size. A control station apparatus in a wireless communication system that divides information blocks and distributes the information blocks via the base station apparatus,
Distribution information storage means for storing the distribution information;
Initial block number holding means for calculating and holding the number of initial information blocks N1 that the base station apparatus can deliver to the mobile body while the mobile body moves at a predetermined speed in the communication area of the base station apparatus; ,
Variation value holding means for holding a variation value n of the number of information blocks to be distributed;
Minimum block number holding means for holding the minimum number of information blocks Nmin distributed by the base station apparatus;
The information block stored in the distribution information storage means is transferred to each base station apparatus in the traveling direction of the mobile body for each of the initial information block numbers N1 held in the initial block number holding means. First block allocating means for allocating as an information block for distribution to,
The number of information blocks obtained by subtracting the variation value n held in the variation value holding means from the initial information block number N1 is set as an update information block number N2 (provided that (N1-n) <Nmin). , N2 = Nmin) and the number of update block holding means to hold,
From the information block for distribution already assigned to the base station apparatus, an information block whose distribution order from each base station apparatus to the mobile body is not within the update block number N2 is extracted as a retransmission information block, and the update block The number of information blocks is the number of update blocks in the base station apparatus to which the distribution information block less than the number N2 is allocated and the base station apparatus to which the distribution information block is unallocated and ahead of the moving body. Second block allocating means for allocating the retransmission information block as a distribution information block so as to be N2 or less;
When the update block number N2 of the second block allocation means exceeds the minimum information block number Nmin, the variation value is calculated from the update information block number N2 held in the update block number holding means. The number of information blocks obtained by subtracting n is set as a new update information block number N2 (however, if (N2-n) <Nmin, N2 = Nmin), the update block number holding means is updated, Control means for repeating the processing by the block allocation means of 2 until the update information block number N2 becomes equal to or less than the minimum information block number Nmin;
Means for distributing the information block assigned to the base station device to each base station device;
A control station apparatus comprising: A plurality of base station devices and a control station device connected thereto, and distribution information held in the control station device is transmitted to a mobile body that moves between communication areas of the base station device with a predetermined size. A control station apparatus in a wireless communication system that divides information blocks and distributes the information blocks via the base station apparatus,
Distribution information storage means for storing the distribution information;
Initial block number holding means for calculating and holding the number of initial information blocks N1 that the base station apparatus can deliver to the mobile body while the mobile body moves at a predetermined speed in the communication area of the base station apparatus; ,
Variation value holding means for holding a variation value n of the number of information blocks to be distributed;
Minimum block number holding means for holding the minimum number of information blocks Nmin distributed by the base station apparatus;
The information block stored in the distribution information storage means is transferred to each base station apparatus in the traveling direction of the mobile body for each of the initial information block numbers N1 held in the initial block number holding means. First block allocating means for allocating as an information block for distribution to,
The number of information blocks obtained by subtracting the variation value n held in the variation value holding means from the initial information block number N1 is set as an update information block number N2 (provided that (N1-n) <Nmin). , N2 = Nmin) and the number of update block holding means to hold,
From the distribution information block already assigned to the base station apparatus, an information block whose distribution order from each base station apparatus to the mobile is not within the update block number N2 is extracted as a retransmission information block, and the distribution block Second block allocation for allocating the retransmission information block as a distribution information block to a base station apparatus that has not been allocated an information block and is ahead of the moving body in the traveling direction so that the number of information blocks is equal to or less than the number of update blocks N2 Means,
When the update block number N2 of the second block allocation means exceeds the minimum information block number Nmin, the variation value is calculated from the update information block number N2 held in the update block number holding means. The number of information blocks obtained by subtracting n is set as a new update information block number N2 (however, if (N2-n) <Nmin, N2 = Nmin), the update block number holding means is updated, Control means for repeating the processing by the block allocation means of 2 until the update information block number N2 becomes equal to or less than the minimum information block number Nmin;
Means for distributing the information block assigned to the base station device to each base station device;
A control station apparatus comprising:   The initial information block number N1 is determined using a preset moving speed of the mobile body that passes through the communication area of the base station apparatus, a transmission speed of information blocks by the base station apparatus, and a communication area size of the base station apparatus. The control station apparatus according to claim 1, wherein:   4. The control station apparatus according to claim 1, wherein the initial information block number N <b> 1 is determined using information block reception capability of a mobile unit. 5.   5. The control station according to claim 1, wherein the initial information block number N <b> 1 is determined using a measurement result of a speed of a moving body that has passed through a communication area of the base station device before information block allocation. apparatus.   The minimum number of information blocks Nmin, the maximum speed allowed for a mobile at the place where the base station apparatus is installed, the transmission speed of information blocks by the base station apparatus, and the communication area size of the base station apparatus The control station apparatus according to claim 1, wherein the control station apparatus is determined by using the control station apparatus.   It is further characterized by further comprising means for invalidating the information block of each of the base station devices deployed for the mobile body upon receiving that all information blocks have been acquired from the mobile body and receiving the information block. The control station apparatus according to claim 1 to 6. A plurality of base station devices and a control station device connected thereto, and distribution information held in the control station device is transmitted to a mobile body that moves between communication areas of the base station device with a predetermined size. A computer program for a control station that operates on the control station device in a wireless communication system that divides information blocks and distributes the information block via the base station device,
The control station device
Distribution information storage means for storing the distribution information;
Initial block number holding means for calculating and holding the number of initial information blocks N1 that the base station apparatus can deliver to the mobile body while the mobile body moves at a predetermined speed in the communication area of the base station apparatus; ,
Variation value holding means for holding a variation value n of the number of information blocks to be distributed;
A minimum block number holding means for holding the minimum number of information blocks Nmin distributed by the base station device;
The computer program for the control station is
The information block stored in the distribution information storage means is transferred to each base station apparatus in the traveling direction of the mobile body for each of the initial information block numbers N1 held in the initial block number holding means. A first block allocation step for allocating as an information block for distribution to
The number of information blocks obtained by subtracting the variation value n held in the variation value holding means from the initial information block number N1 is set as an update information block number N2 (provided that (N1-n) <Nmin). , N2 = Nmin), the update block number holding step held in the update block number holding means;
From the information block for distribution already assigned to the base station apparatus, an information block whose distribution order from each base station apparatus to the mobile body is not within the update block number N2 is extracted as a retransmission information block, and the update block The number of information blocks is the number of update blocks in the base station apparatus to which the distribution information block less than the number N2 is allocated and the base station apparatus to which the distribution information block is unallocated and ahead of the moving body. A second block allocation step of allocating the retransmission information block as a distribution information block so as to be N2 or less;
When the number of update blocks N2 in the second block allocation step exceeds the minimum number of information blocks Nmin, the variation value is calculated from the number of update information blocks N2 held in the update block number holding means. The number of information blocks obtained by subtracting n is set as a new update information block number N2 (however, if (N2-n) <Nmin, N2 = Nmin), the update block number holding means is updated, A control step of repeating the process of block allocation step 2 until the update information block number N2 is equal to or less than the minimum information block number Nmin;
Instructing the information block allocated to the base station apparatus to be distributed to each base station apparatus;
Is executed by the control station apparatus. A plurality of base station devices and a control station device connected thereto, and distribution information held in the control station device is transmitted to a mobile body that moves between communication areas of the base station device with a predetermined size. A computer program for a control station that operates on the control station device in a wireless communication system that is divided into information blocks and distributed via the base station device,
The control station device
Distribution information storage means for storing the distribution information;
Initial block number holding means for calculating and holding the number of initial information blocks N1 that the base station apparatus can deliver to the mobile body while the mobile body moves at a predetermined speed in the communication area of the base station apparatus; ,
Variation value holding means for holding a variation value n of the number of information blocks to be distributed;
A minimum block number holding means for holding the minimum number of information blocks Nmin distributed by the base station device;
The computer program for the control station is
The information block stored in the distribution information storage means is transferred to each base station apparatus in the traveling direction of the mobile body for each of the initial information block numbers N1 held in the initial block number holding means. A first block allocation step to allocate as an information block for distribution to,
The number of information blocks obtained by subtracting the variation value n held in the variation value holding means from the initial information block number N1 is set as an update information block number N2 (provided that (N1-n) <Nmin). , N2 = Nmin), the update block number holding step held in the update block number holding means;
From the distribution information block already assigned to the base station apparatus, an information block whose distribution order from each base station apparatus to the mobile is not within the update block number N2 is extracted as a retransmission information block, and the distribution block Second block allocation for allocating the retransmission information block as a distribution information block to a base station apparatus that has not been allocated an information block and is ahead of the moving body in the traveling direction so that the number of information blocks is equal to or less than the number of update blocks N2 Steps,
When the number of update blocks N2 in the second block allocation step exceeds the minimum number of information blocks Nmin, the variation value is calculated from the number of update information blocks N2 held in the update block number holding means. The number of information blocks obtained by subtracting n is set as a new update information block number N2 (however, if (N2-n) <Nmin, N2 = Nmin), the update block number holding means is updated, A control step of repeating the processing by the block allocation step of 2 until the update information block number N2 is equal to or less than the minimum information block number Nmin;
Instructing the information block allocated to the base station apparatus to be distributed to each base station apparatus;
Is executed by the control station apparatus.

Images