Abstract:
A push service system and a terminal used in the system are operated according to a following operation scheme of information transmission. The terminal sends to a host in the system a request for re-transmission of information through a communication network when the terminal returns to a waiting condition from a non-waiting condition. Upon receiving the request, the host requests the communication network to re-transmit the information to the terminal. A non-waiting condition continuation time as a criterion for determining continuation of the non-waiting condition of the terminal is substantially matched with a re-transmission time of the information from the communication network to the terminal for controlling the re-transmission of the information.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application is based on and claims the benefit of priority of Japanese Patent Application No. 2006-114893 filed on Apr. 18, 2006, the disclosure of which is incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention generally relates to a push service system and apparatus used therein. 
       BACKGROUND INFORMATION 
       [0003]    Japanese patent document No. JP-A-2003-288298 describes a general construction example of the conventional information provision system that is connected to a leased line or the Internet and provides a push service.  FIG. 1  shows the system construction. The system includes: an information acquisition terminal A  101  and an information acquisition terminal B  102  connected to a wireless communication network  104 ; an information acquisition terminal C  103  not connected to the wireless communication network  104 ; an information provision host  106  connected to a wired communication network  107  (specifically a leased line or the Internet); and an access server  105  for connecting the wireless communication network  104  with the wired communication network  107 . 
         [0004]    Let us consider that the information provision host  106  provides information to the information acquisition terminals A  101 , B  102 , and C  103 . The information provision host  106  uni-directionally transmits information to these terminals independently of whether or not they are connected to the wireless communication network  104 . In such case, the information acquisition terminals A  101  and B  102  are connected to the wireless communication network  104  and can receive the information provided from the information provision host  106 . 
         [0005]    However, the information acquisition terminal C  103  is not connected to the wireless communication network  104  and cannot receive the information provided from the information provision host  106 . 
         [0006]    As mentioned above, the push service aims at providing information to the information acquisition terminal. The push service allows the information provision host to provide information to the information acquisition terminal without obliging an information acquisition terminal user to explicitly accessing the information provision host. The information denotes various content information needed by users and is hereafter referred to as push service information. 
         [0007]    The push service allows the information provision host to unilaterally provide push service information independently of whether or not an information acquisition terminal requiring the push service information is capable of wireless communication. When the information acquisition terminal is not connected to the wireless communication network (hereafter referred to as being out of wireless communication service), that terminal cannot receive push service information transmitted from the information provision host according to the technology in  FIG. 1 . The user at least needs to always connect the information acquisition terminal to the wireless communication network so as to be able to receive necessary push service information. 
         [0008]    There may be provided conversation unit for establishing a voice call between information acquisition terminals. Some information acquisition terminals are simultaneously capable of conversation and data communication compatible with W-CDMA (Wideband Code Division Multiple Access), for example. The other information acquisition terminals generally share a channel for the push service and a channel for the conversation so as to connect to the wireless communication network. In this case, it is impossible to simultaneously carry on a conversation and provide the push service. While the information acquisition terminal is using the conversation function, the terminal cannot receive push service information from the information provision host similarly to the state being out of wireless communication service. 
         [0009]    In this manner, the information acquisition terminal may not be able to receive push service information at a time it is provided. In general, the access server periodically retransmits the push service information to the information acquisition terminal for a specified time period. After lapse of the specified time period, the access server stops the retransmission and notifies the information provision host of unsuccessful transmission. In response to this notification, the information provision host provides the known retransmission control and requests the access server to retransmit the push service information to the information acquisition terminal. 
         [0010]    However, the system is subject to problems as shown in  FIGS. 2 and 3 .  FIG. 2  assumes that push service information is transmitted when an information acquisition terminal is out of wireless communication service.  FIG. 3  assumes that push service information is transmitted while an information acquisition terminal is carrying on a conversation. 
         [0011]    When the information acquisition terminal is out of wireless communication service in  FIG. 2 , the access server finishes transmitting the push service information after a specified time period and notifies the information provision host of unsuccessful transmission. While the information provision host controls retransmission of the push service information, the information acquisition terminal may move to temporarily become in service (a state capable of wireless communication), and then move to a region where no wireless communication service is available. In such case, the access server thereafter receives a transmission request under retransmission control of the information provision host and retransmits the push service information. The information acquisition terminal nevertheless cannot receive the retransmitted push service information. The information provision host is necessitated to provide the retransmission control. The retransmission under the retransmission control causes an unnecessary communication traffic. The same applies to a situation where the information acquisition terminal carries on a conversation, disables it in wireless communication service (hereafter referred to as standby), and then restarts the conversation or becomes out of wireless communication service ( FIG. 3 ). 
       SUMMARY OF THE INVENTION 
       [0012]    In view of the above and other problems, the present invention provides a push system and terminal that prevents unnecessary communication traffic between a terminal and a host in a communication network. 
         [0013]    The push service system of the present disclosure includes a terminal for acquiring information when wireless communication is established between the terminal and a communication network and a host for providing information for the terminal regardless of a condition of wireless communication of the terminal. The terminal requests the host through the wireless communication to provide the information when the terminal resumes the wireless communication after a predetermined period of lack of wireless communication with the communication network. In this manner, the retransmission of the information to the terminal is provided only when the re-transmission is explicitly requested from the terminal that has returned to a wireless communication service area after a predetermined time of non-serviceable condition, thereby preventing unnecessary communication traffic. 
         [0014]    The operation scheme of the host and the terminal in the push service system may be described as a function of a terminal side. Further, the operation scheme may be described as alternation of a voice call and data communication, and accordingly the function of the terminal side. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    Other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which: 
           [0016]      FIG. 1  shows a block diagram of a conventional push service system; 
           [0017]      FIG. 2  shows a sequence chart of information re-transmission in the conventional push service system; 
           [0018]      FIG. 3  shows another sequence chart of information re-transmission in the conventional push service system; 
           [0019]      FIG. 4  show a block diagram of a push service system and a terminal in an embodiment of the present disclosure; 
           [0020]      FIG. 5  shows a flowchart of data transmission process of the push service system and the terminal in the embodiment; 
           [0021]      FIG. 6  shows a sequence chart of information re-transmission in the push service system in the embodiment of the present disclosure; and 
           [0022]      FIG. 7  shows another sequence chart of information re-transmission in the push service system in the embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    An embodiment of the invention will be described in further detail with reference to  FIGS. 4 and 5 .  FIG. 4  schematically shows the construction of a push service system and an information acquisition terminal according to the invention. A push service system  400  according to the invention includes: an information provision host  410  that maintains push service information and provides a push service; a communication network  420  that is connected to the information provision host  410  via wired communication such as a leased line or the Internet and relays the push service information; an information acquisition terminal  430  that is connected to the communication network  420  via wireless communication and receives the push service information. More specifically, the information provision host  410  is equivalent to a push service provider&#39;s information distribution center. The communication network  420  is equivalent to a communication network managed by a telecommunications carrier. The information acquisition terminal  430  is equivalent to a mobile phone owned by a user. 
         [0024]    The information provision host  410  includes: a data storage unit  411  that stores push service information; a host communication unit  412  that exchanges push service information; and a host processing unit  413  that controls these units. When push service information is updated, the host processing unit  413  acquires the push service information updated by the host communication unit  412  and delivers the push service information to the communication network  420 . The communication network  420  includes: an access server  422  that transmits push service information to the information acquisition terminal  430 ; and multiple wireless base stations  421  that are connected to the access server via wired lines. The communication network  420  transmits push service information delivered via the wireless base station  421  to the information acquisition terminal  430 . 
         [0025]    The information acquisition terminal  430  includes: a terminal communication unit  431  that communicates data for push service information; out-of-service determination unit  432  that determines whether or not the terminal remains being out of wireless communication service; conversation determination unit  433  that determines whether or not the terminal continues carrying on a conversation; and a terminal processing unit  434  that controls these components. 
         [0026]    The out-of-service determination unit  432  uses time keeping unit (not shown) to measure a time period after the information acquisition terminal  430  becomes incapable of wireless communication. When the disabled wireless communication continues for a specified time period or longer, the out-of-service determination unit  432  notifies the terminal processing unit  434  that the information acquisition terminal  430  remains out of wireless communication service. The specified time period is hereafter referred to as a continued out-of-service time. The conversation determination unit  433  uses the time keeping unit to measure a time period during which a channel connected to the communication network  420  is used for conversation. When the channel is continuously used for a specified time period or longer, the conversation determination unit  433  notifies the terminal processing unit  434  that the information acquisition terminal  430  continues carrying on a conversation. The specified time period is hereafter referred to as a continued conversation time. 
         [0027]    The following describes information interchange between the elements (information provision host  410 , communication network  420 , and information acquisition terminal  430 ) of the push service system according to the embodiment with reference to the schematic diagram in  FIG. 4  and a data communication flowchart in  FIG. 5 . The description below uses reference numerals in  FIGS. 4 and 5  when needed. 
         [0028]    The invention is characterized by the way of interchanging push service information when a push service is provided while the information acquisition terminal  430  is out of wireless communication service or is carrying on a conversation. The construction of the push service system  400  up to the stage of delivering push service information conforms to the technology described in “Description of Related Art” with reference to  FIG. 1 . The push service according to the embodiment premises SMS (Short Message Service). The push service information is equivalent to a short message, i.e., character data containing the limited number of characters. The short message is hereafter referred to as an SMS. In more detail, the SMS includes current information such as news needed by users, information (hereafter referred to as maintenance information) about limitation on the use of the push service system for its improvement and repair, information (hereafter referred to as security information) from the information provision host for keeping track of a terminal when it is stolen, and emergency information such as disaster information. 
         [0029]    The information acquisition terminal  430  complies with a communication system other than the multi-call system such as W-CDMA capable of simultaneously processing data communication and conversation. 
         [0030]    The flowchart in  FIG. 5  assumes a situation where the information provision host delivers an SMS while the information acquisition terminal  430  is not on standby (out of wireless communication service or during a voice call). In  FIG. 5 , a hundred&#39;s digit of a number assigned to each step corresponds to the element of the system. The step indicates an operation for the corresponding element. Digit 1 corresponds to the information provision host  410 . Digit 2 corresponds to the communication network  420 . Digit 3 corresponds to the information acquisition terminal  430 . 
         [0031]    Updating an SMS maintained in the information provision host  410  starts the flowchart (Step  5100 ). The information provision host  410  transmits the SMS to the information acquisition terminal  430 . For this purpose, the information provision host  410  requests the intermediate communication network  420  to transmit the SMS to the information acquisition terminal  430  and transmits the requested SMS to the communication network  420  (Step  5110 ). 
         [0032]    The communication network  420  transmits the SMS to the information acquisition terminal  430  (Step  5200 ). The push service system  400  proceeds to Step  5300 . At Step  5300 , the system determines whether or not the information acquisition terminal  430  is on standby. When the information acquisition terminal  430  is on standby (yes at Step  5300 ), the system proceeds to Step  5310 . When the information acquisition terminal  430  is out of wireless communication service or is carrying on a conversation (no at Step  5300 ), the system measures a time period when the out-of-service determination unit  432  becomes out of wireless communication service or the conversation determination unit  433  becomes busy (Step  5301 ). The system then proceeds to Step  5210 . As mentioned above, the initial state of the flowchart assumes that the information acquisition terminal  430  is out of wireless communication service or is carrying on a conversation. It should be noted that the system starts measuring the time period at Step  5301  under the condition of being out of wireless communication service or being busy and continues the measurement. 
         [0033]    The following describes in more detail the process when Step  5300  results in the affirmative (yes). In this case, the push service system  400  proceeds to Step  5310 . At Step  5310 , it is determined whether or not to request transmission of the SMS when the information acquisition terminal  430  restores the standby state from the state being out of wireless communication service or the conversation state. More specifically, let us suppose that the information acquisition terminal  430  restores the standby state from the state being out of wireless communication service. When the time period measured by the out-of-service determination unit  432  is shorter than or equal to the continued out-of-service time (yes at Step  5310 ), the system proceeds to Step  5320 . This is because the information acquisition terminal  430  can receive the retransmitted SMS from the communication network  420 . When the measured time period exceeds the continued out-of-service time (no at Step  5310 ), it is clear that the communication network  420  retransmits no SMS. This is because the continued out-of-service time matches the time to retransmit the SMS from the communication network  420 . In this case, the information acquisition terminal  430  issues a request for transmitting the SMS to the information provision host  410  via the communication network  420  (Step  5340 ). 
         [0034]    When the information acquisition terminal  430  restores the standby state from the conversation state, the system follows a process flow similar to the above-mentioned one based on the measured time period. 
         [0035]    At Step  5320 , it is determined whether or not the information acquisition terminal  430  receives the SMS retransmitted from the communication network  420 . When the information acquisition terminal  430  receives the SMS (yes at Step  5320 ), the system proceeds to Step  5330 . The information acquisition terminal  430  transmits an acknowledgment signal (hereafter referred to as an ACK signal) to the communication network  420  in Step  5330 . This signal indicates that the information acquisition terminal  430  has received the SMS. The communication network  430  then proceeds to Step  5210 . 
         [0036]    When Step  5320  results in the negative (no), the system proceeds to Step  5210 . This is because the information acquisition terminal  430  can receive the retransmitted SMS from the communication network  420 . 
         [0037]    The following describes in more detail the process when Step  5300  results in the negative (no), i.e., at Step  5210  and later. At Step  5210 , the system determines whether or not the communication network  420  receives the ACK signal for notifying completion of the SMS reception from the information acquisition terminal  430 . When the ACK signal is received (yes at Step  5210 ), the SMS is successfully transmitted to the information acquisition terminal  430 . The communication network  420  notifies the information provision host  410  of the successfully SMS transmission (Step  5220 ). The information provision host  410  deletes the corresponding SMS from the data storage unit  411  (Step  5120 ). The system terminates a sequence of push service transmission (Step  5130 ). 
         [0038]    When the communication network  420  does not receive the ACK signal at Step  5210  (no at Step  5210 ), the communication network  420  proceeds to the retransmission of the SMS at Step  5230  and later. The communication network  420  measures a time period elapsed from the time when the first SMS is transmitted to the information acquisition terminal  430 . When the time period is within a predetermined retransmission time (no at Step  5230 ), the communication network  420  periodically transmits the SMS to the information acquisition terminal  430 . When the measured time period exceeds the retransmission time (yes at Step  5230 ), the communication network  420  determines that the retransmission fails. The communication network  420  notifies the information provision host  410  of unsuccessful transmission of the SMS (Step  5240 ). 
         [0039]    The information provision host  410  stores the corresponding SMS in the data storage unit and settles an expiration date for the SMS from that time point (Step  5140 ). The expiration date is settled for the SMS because the information may become useless for the user after a specified time period. For example, the current information such as discounts on merchandise and today&#39;s news is limited to the same date and will be meaningless when it is retransmitted the next day. In this case, the expiration date is settled to the same day. On the other hand, for example, maintenance information needs to be notified as long as possible. The expiration date is settled to be long at least until the maintenance period expires. The expiration date may not be settled for such SMS as related to security or emergency information that needs to be notified reliably. In this case, the SMS is recorded until it is transmitted successfully or the user manually cancels the retransmission. 
         [0040]    Since the expiration date is settled to manage the SMS, it is possible to prevent an unnecessary SMS from being transmitted to the user and decrease an accompanying communication traffic. 
         [0041]    When the expiration date has passed (no at Step  5150 ), the SMS is meaningless to the user as mentioned above. The information provision host  410  deletes the corresponding SMS (Step  5120 ) and terminates the process (Step  5130 ). 
         [0042]    When the expiration date takes effect (yes at Step  5150 ), the SMS is useful for the user. The information provision host  410  makes the SMS ready for retransmission and keeps it stored in the data storage unit  411  (Step  5160 ). Retransmission of the SMS is triggered when the information provision host  410  receives the SMS transmission request transmitted from the information acquisition terminal  430  at Step  5340  (yes at Step  5160 ). When the SMS transmission request is not received (no at Step  5160 ), the information provision host  410  manages the expiration date for the SMS (Step  5150 ). 
         [0043]    Although the present invention has been fully described in connection with the preferred embodiment thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. 
         [0044]    For example, the terminal  430  may be a radio installed on a vehicle or the like. In this case, the terminal  430  on, for example, a stolen car may be traced by using GPS system, and the position of the car may be reported to a police or the like. The vehicle might be moved to an area where the wireless communication is out of service, tracking of the vehicle may be resumed as soon as the vehicle moves back to the service area by using SMS. 
         [0045]    Because the continued out-of-service time used in Step  5130  (or the continued out-of-service/busy time) is matched with the time for re-transmission of SMS from the server  420 , the re-transmission of SMS may be received by the terminal  430  when the terminal  430  returns to a waiting condition or returns to in-service area while SMS is re-transmitted. That is, a condition that the terminal  430  can not receive the re-transmitted SMS due to the SMS re-transmission time being shorter than the continued out-of-service time is prevented. In this case, the continued out-of-service time may only roughly match the time for SMS re-transmission for effectively preventing the above condition. 
         [0046]    Further, the above operation scheme can prevent unnecessary SMS transmission request to the host  410 , thereby preventing unnecessary transmission from the host  410 . In this manner, the useless traffic in the push service system  400  is achieved. 
         [0047]    Furthermore, as shown in  FIGS. 6 and 7 , the terminal  430  sends the request for SMS transmission to the host  410  through the network  420  when the terminal  430  returns to the serviced condition or the busy condition after continued out-of-service time/busy time is longer than the set time. In this manner, the host  410  can send the SMS to the  430  with increased probability and without controlling re-transmission in the conventional manner. 
         [0048]    Furthermore, the not-delivered SMS managed with expiration data makes it possible to eliminate reception of useless SMS by the terminal  430 . In this manner, the terminal  430  can receive SMS being transmitted during the out-of-service/busy period as soon as possible after returning to the serviced condition. 
         [0049]    Such changes and modifications are to be understood as being within the scope of the present invention as defined by the appended claims.