Abstract:
A radio communication network system provides a method of managing radio communication base stations and mobile terminals for accomplishing an access to the Internet from a mobile terminal and communications between mobile terminals. A base station management terminal, radio communication base stations, and mobile terminals reference their communication path information created by exchanging their adjacent terminal information and communication path information to ensure their respective communication paths to other terminals. Even if two mobile terminals cannot communicate due to their radiowaves failing to arrive at their destinations, the mobile terminals can provide a communication path for making communications therebetween through a communication line, the radio communication base station, and the base station management terminal.

Description:
INCORPORATION BY REFERENCE  
       [0001]     The present application claims priority from Japanese application JP2004-185791 filed on Jun. 24, 2004, the content of which is hereby incorporated by reference into this application.  
       BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to data transmission/reception technologies and information communication technologies between a terminal and a base station in a radio communication network.  
         [0003]     An ad hoc network technology utilizes radio communications to build a network at a site itself at which terminals are brought together. This technology mainly features in that terminals recognize one another for connection to transmit and receive information about adjacent terminals to and from one another to build a multi-hop communication environment. In the multi-hop communication environment, terminals which cannot directly communicate with each other on the air can utilize other terminals located between these terminals as communication relay terminals to make communications therebetween.  
         [0004]     On the other hand, a service has been provided for enabling mobile terminals to access the Internet through radio base stations installed for this purpose. For example, JP-A-2003-249937 discloses a radio communication system which addresses a situation in which a mobile terminal cannot directly communicate with a radio base station due to a difference in mode such as an infrastructure mode, an ad hoc mode and the like, a difference in radio communication frequency, and the like, and enables communications between the mobile terminal and the radio base station through an installed communication relay terminal which has a plurality of interfaces that enable communications in different modes at different frequencies, thereby permitting the mobile terminal to access the Internet.  
         [0005]     In a well established radio communication environment which supports a number of mobile terminals, each of which can communicate with a plurality of radio base stations, a certain mobile terminal can access the Internet through a plurality of possible communication paths, giving rise to a need for selecting and setting an optimal communication path. However, the aforementioned JP-A-2003-249937 does not describe a radio base station for communications with an optimal quality or a method of selecting and setting an optimal communication path in a mobile terminal and a radio base station for sending communication packets to an Internet gateway.  
         [0006]     Therefore, a need exists for a method of accessing the Internet from a mobile terminal at any site with a high quality, making use of a plurality of radio base stations.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention provides a method of managing mobile terminals which have the multi-hop communication ability, and a radio communication base station which enables the mobile terminals to access the Internet.  
         [0008]     The present invention provides a mechanism which permits a mobile terminal to select a communication base station which offers an optimal communication quality from among a plurality of communication base stations in a situation where a plurality of mobile terminals are in course of multi-hop communications implemented by the aforementioned ad hoc network technology.  
         [0009]     The present invention provides a mechanism which permits mobile terminals belonging to different groups of mobile terminals from each other to communicate with each other through a wired network such as base station facilities, Internet networks and the like even if a mobile terminal belonging to a certain group of mobile terminal and a mobile terminal belonging to another group of mobile terminals cannot make multi-hop communication with each other over the air due to limitations in a radio accessible distance in a situation where a plurality of mobile terminals are making multi-hop communications implemented by the ad hoc network technology.  
         [0010]     The present invention also provides a mobile terminal which has the ability to determine in accordance with a particular situation of the mobile terminal whether a communication should be made through a communication path provided through radio base stations and communication lines as mentioned above, or through a radio communication path implemented by the ad hoc network technology without utilizing the communication line.  
         [0011]     The present invention also provides a mechanism which permits each mobile terminal to select and set an optimal communication path for sending communication packets to a terminal having an Internet gateway function with reference to communication path information which is created by respective mobile terminals which exchange information on their adjacent terminals.  
         [0012]     The present invention also provides a mechanism which permits each mobile terminal to detect a communication path through which the terminal sends communication packets to a terminal which has an Internet gateway function.  
         [0013]     With this mechanism, even if a mobile terminal cannot directly communicate with a radio communication base station, the mobile terminal can communicate with the radio communication base station through other mobile terminals, serving as relay terminals, to access the Internet.  
         [0014]     The present invention also provides means through which a base station management terminal, a radio communication base station, and a mobile terminal exchange respective information about adjacent terminals and communication paths with one another, thereby permitting each terminal to keep track of communication paths to other terminals.  
         [0015]     In this way, even if two mobile terminals cannot communicate with each other due to an excessively long distance beyond their accessing abilities, the mobile terminals can set up a communication path for communicating therebetween through a communication line, the radio communication base station, a base station management terminal, and even other mobile terminals.  
         [0016]     Also, even if a mobile terminal moves between coverage areas of respective radio communication base stations, an optimal communication path can be selected for accessing the Internet.  
         [0017]     According to the present invention, the mobile terminal can access the Internet even if the mobile terminal is located out of a coverage area of a radio communication base station.  
         [0018]     Other objects, features and advantages of the invention will become apparent from the following description of the embodiments of the invention taken in conjunction with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]      FIG. 1  is a block diagram illustrating an exemplary configuration of a system in one embodiment of the present invention;  
         [0020]      FIG. 2  is a block diagram illustrating the hardware configuration of a communication terminal associated with one embodiment;  
         [0021]      FIG. 3  is a diagram illustrating a terminal management method according to one embodiment;  
         [0022]      FIG. 4  is a diagram illustrating another terminal management method according to one embodiment;  
         [0023]      FIG. 5  is a diagram illustrating an Internet access method according to one embodiment;  
         [0024]      FIG. 6  is a diagram illustrating another Internet access method according to one embodiment;  
         [0025]      FIG. 7  is a diagram illustrating an inter-terminal communication method according to one embodiment; and  
         [0026]      FIG. 8  is a diagram illustrating another inter-terminal communication method according to one embodiment. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0000]     1. Basic Device Configuration  
         [0027]      FIG. 1  is a block diagram illustrating a logical configuration according to one embodiment of the present invention.  
         [0028]     Each of mobile terminals  37   a - 37   c  (collectively designated by  37 ) has a radio communication function  39 , a communication path setting function  43 , and an adjacent terminal information management function  45 . An adjacent terminal refers to a mobile terminal which is located within one hop (which is a distance over which radiowaves can directly attain from another mobile terminal).  
         [0029]     A plurality of mobile terminals  37  can be connected to one another in radio communications. These mobile terminals  37  may have a data transfer function so that they relay data, thereby enabling communications between a plurality of mobile terminals  37  which are located beyond a distance over which radiowaves can directly attain. A communication path for making the foregoing communication is dynamically changed by the communication path setting function  43  based on adjacent terminal information mutually transmitted and received on a periodic basis by the adjacent terminal information management functions  45  of the respective mobile terminals in accordance with a change in the positional relationship between the mobile terminals  37 , a change in the radio communication situation, or the like.  
         [0030]     A radio communication base station (hereinafter called the “base station”)  11  can take (a) a configuration implemented by an infrastructure mode communication base station  13  and communication relay device  15 , or (b) a configuration implemented by a communication relay device  27 . The infrastructure mode refers to a communication mode in which a communications is made through an access point.  
         [0031]     A communication relay device  15  in the base station (a) has a communication path setting function  23 , an adjacent terminal information management function  25 , and a base station radio interface direct communication blocking function  26 . The radio communication function  17  comprises an infrastructure mode communication function  19 , and an ad hock mode communication function  21  for an ad hoc mode in which a peer-to-peer communication is made with another device which has a communication function, bypassing an access point. The two functions  19 ,  21  can be operated in parallel.  
         [0032]     The infrastructure mode communication base station  13  is connected to a wired network such as the Internet  48 (hereinafter called the “Internet”), and also communicate with the infrastructure mode communication function  19 . The ad hoc mode communication function  21  makes communications with an ad hoc mode communication function  41  of the mobile terminal  37 .  
         [0033]     The base station  11  may use the base station radio interface direct communication blocking function  26  for making a setting to prevent radio communications with another base station. This setting prevents a closed communication path which would cause MAC (Media Access Control) frames and communication packets to loop around the closed communication path to result in a failed communication.  
         [0034]     The communication relay device  27  in the base station (b) has a radio communication function  29 , communication path setting function  23 , adjacent terminal information management function  25 , and base station radio interface direct communication blocking function  26 . The radio communication function  17  has the ad hoc mode communication function  21 . The communication relay device  27  is connected to a wired network (Internet  48 ) through a communication line.  
         [0035]     In both configurations (a), (b) described above, the base station  11  has an Internet gateway function  24 ,  34 . The Internet gateway function  24 ,  34  forces the base station  11  to function as a relay point when the mobile terminal  37  accesses an Internet site such as an information delivery server  10 .  
         [0036]     A base station management terminal  1  has an Internet gateway function  3 , a base station management function  5 , a communication path setting function  7 , and an adjacent terminal information management function  9 . The Internet gateway function  3  is provided for the base station management terminal  1  to act as a relay point when the base station  11  or mobile terminal  37  accesses an Internet site such as the information delivery server  10 . The base station management function  5  manages information on communication paths to the base station  11  and mobile terminal  37 . The base station management terminal  1  is connected to the Internet  48 .  
         [0037]     When a network such as the Internet  48  intervenes between the base station management terminal l and the base station  11 , the adjacent terminal information can be exchanged between the base station management terminal  1  and the base station  11  using a known tunnel technique or the like.  
         [0038]     The base station management terminal  1 , communication relay devices  15 ,  27  of the base station  11 , and mobile terminal  37  exchange the adjacent terminal information with one another, respectively, using their adjacent terminal information management functions  9 ,  25 ,  45 , to keep track of the network topology, and set communication paths for their associated terminals, respectively, using their communication path setting functions  7 ,  23 ,  43 .  
         [0039]      FIG. 2  is a block diagram illustrating an exemplary physical configuration of a general information processing apparatus which can embody the base station management terminal  1 , the communication relay devices  15 ,  27  of the base station  11 , and the mobile terminal  37 .  
         [0040]     Specifically, the illustrated information processing apparatus comprises a processor  51  for executing an information processing program  61 ; a memory  53  for storing the information processing program  61  executed by the processor  51 , and a variety of data referenced by the processor  51 ; a non-volatile external storage device  55  for storing the information processing program  61  and a variety of data; a wired communication interface unit  58  for connection to the Internet  48  to transmit and receive data to and from another information processing apparatus or a communication device; a radio communication interface device  57  for transmitting and receiving data to and from another information processing apparatus or a communication device through radio communications; and an input/output device  63  involved in input/output with the operator. These components are interconnected through a communication line  59  such as a bus (hereinafter called the “bus”).  
         [0041]     The information processing program  61  contains procedure information for implementing the respective functions listed above on an information processing apparatus, when it is executed by the processor  51 . Specifically, the information processing program  61  implements functions for interacting with a viewer or an operator through the input/output device  63  as required, inputting and outputting data between the external storage device  55  and the memory  53 , reading data stored in the memory  53  through the wired communication interface unit  58  and radio communication interface unit  57 , and transmitting data on the memory  53  to another information processing apparatus.  
         [0042]     The information processing program  61  may be previously stored in the memory  53  or external storage device  55 , or loaded into the information processing apparatus from another device through a portable storage medium or a communication medium (a network, or a carrier wave, a digital signal and the like which propagate through a network) available for the information processing apparatus.  
         [0043]     The respective functions described above may be implemented by dedicated hardware components.  
         [0044]     In this embodiment, two management methods, i.e., a hierarchical management method and a non-hierarchical management method are illustrated for managing the mobile terminals and radio base stations.  
         [0045]     In the hierarchical management method, each base station manages mobile terminals which can communicate with the base station directly or in the multi-hop mode. Specifically, (1) each base station ensures a communication path information for communicating with a mobile terminal (by exchanging adjacent terminal information with the mobile terminal). (2) Each base station transmits the communication path information to the base station management terminal. (3) The base station management terminal detects a communication path to each mobile terminal with reference to the communication path information to create communication path information.  
         [0046]     With the foregoing configuration, the adjacent terminal information is exchanged only between a base station and those mobile stations which are accommodated in the base station. Therefore, even if there are a large number of base stations and mobile stations, the adjacent terminal information is not exchanged beyond the base station management terminal, resulting in a reduction in traffic which is caused by the exchange of the adjacent terminal information. However, the base stations and base station management terminal are required to have the functions (2), (3).  
         [0047]     In the non-hierarchical management method, on the other hand, the adjacent terminal information is exchanged among all terminals, i.e., the base station management terminal, base stations, and mobile terminals. Therefore, when there are a large number of base stations and mobile terminals, an increase in the traffic results from the exchange of the adjacent terminal information. However, the base station and base station management terminal can be simpler in configuration because they do not require such functions as the aforementioned functions (2), (3).  
         [0000]     2. Hierarchical Mobile Terminal Management Method  
         [0048]     A method of managing the mobile terminals  37  and base station  11  will be described with reference to  FIG. 3 .  
         [0000]     ( 301 )  
         [0049]     The base station  11  and mobile terminals  37  repeatedly communicate their respective adjacent terminal information with each other using the adjacent terminal information management functions  44  (for example, on a periodic basis) to create communication path information using the communication path setting functions  23 ,  43 , respectively, and set the communication path information therein.  
         [0050]     The adjacent terminal information includes (1) the address of a terminal which has transmitted the adjacent terminal information (adjacent terminal information originating terminal); (2) the addresses of terminals which are adjacent to the terminal which has transmitted the adjacent terminal information; (3) a situation as to how the terminal which has transmitted the adjacent terminal information is located with respect to the “terminals adjacent to the terminal which has transmitted the adjacent terminal information” (for example, the adjacent terminal information can be communicated in two directions, the adjacent terminal information can be communicated only in one direction, the adjacent terminal information has not been communicated for a certain period, and the like), and the like.  
         [0051]     The adjacent terminal information, when communicated, can be contained, for example, in a communication packet such as OSPF (Open Shortest Path First) which is a known protocol implemented in routers, “Hello Message” repeatedly communicated between devices in OLSR (Optimized Link State Routing Protocol), which is a routing protocol of the ad hoc network, and the like.  
         [0052]     Each of the communication path setting functions  23 ,  43  determines a communication path upon transmission of communication packets in accordance with the type of a communication path (whether it consists only of a radio communication path or includes a wired communication path), the number of times of hopping until a destination node, the amount of a remaining battery in a communication relay terminal, a radio field strength between terminals in communication, the communication performance such as a delay time between the terminals in communication, throughput, packet loss rate, and jitter, and so forth.  
         [0053]     The adjacent terminal information may be communicated at regular intervals or at a period which is varied in accordance with at least one of combinations among a moving speed of the mobile terminal and its changing rate, and a radio field strength associated with adjacent terminals and its changing rate.  
         [0000]     ( 302 )  
         [0054]     Each of the base station  11  (ST-x), (x=A, B, . . . ) repeatedly transmits its communication path information  65  (TABLE (ST-x)) to the base station management terminal  1  (for example, on a periodic basis)  
         [0000]     ( 303 )  
         [0055]     The base station management terminal  1  repeatedly creates communication path information TABLE (Adm) to each of the mobile terminals  37  using the communication path information TABLE (ST-x) sent from each base station, and sets the communication path information TABLE (Adm) therein.  
         [0000]     3. Non-Hierarchical Mobile Terminal Management Method  
         [0056]     A method of managing the mobile terminals  37  and base station  11  will be described with reference to  FIG. 4 .  
         [0057]     The base station B  11   g , mobile terminal BB  37   k , and base station management terminal  1  repeatedly communicate their respective adjacent terminal information with each other using the adjacent terminal information management functions  25 ,  45 ,  9 , respectively, (for example, on a periodic basis) to create their respective communication path information  69  (TABLE (ST-B)),  71  (TABLE (MN-B)),  67  (TABLE(Adm)) using the communication path setting functions  23 ,  43 ,  7 , respectively, and set the communication path information,  69 ,  71 ,  67  therein using the communication path setting functions  23 ,  43 ,  7 , respectively.  
         [0058]     The adjacent terminal information may be communicated at regular intervals, or at a period which is varied in accordance with one or more of a moving speed of the mobile terminal and its changing rate, and a radio field strength associated with adjacent terminals and its changing rate.  
         [0059]     The communication path setting functions  23 ,  43 ,  7  reference the associated communication path information  69 ,  71 ,  67 , respectively, upon transmission of communication packets, to determine communication paths in accordance with the type of a communication path (whether it consists only of a radio communication path or includes a wired communication path), the number of times of hopping until a destination node, the amount of a remaining battery in a communication relay terminal, a radio field strength between the terminals in communication, the communication performance such as a delay time between the terminals in communication, throughput, packet loss rate, and jitter, and so forth. The delay time, throughput, packet loss rate, jitter and the like can be detected using unknown techniques.  
         [0000]     4. Method of Accessing Internet from Mobile Terminal in Hierarchical Mobile Terminal Management Method  
         [0060]     Referring to  FIG. 5 , description will be made on a method of permitting the mobile terminal A  37   m  to send communication packets to the Internet gateway function  3  of the base station management terminal  1  or to the Internet gateway functions  24 ,  34  of the base stations  11 , and permitting the mobile terminal A  37   m  to access the Internet in the multi-hop mode, even if the mobile terminal A  37   m  is out of the coverage area of the base station A  11   h.    
         [0061]     Assume in  FIG. 3 , that the base station A  11   h  and mobile terminal A  37   m  are managed by the management method illustrated in  FIG. 3 .  
         [0000]     &lt;Internet Accessing Method&gt; 
         [0000]     ( 101 )  
         [0062]     Each of the base stations A  11   h , B  11   i  has previously set the base station management terminal  1  having the Internet gateway function  3  as a default gateway in a known method. Alternatively, each of the base stations A  11   h , B  11   i  may contain the Internet gateway function  24 ,  34 . When a certain terminal transmits or forwards communication packets, the terminal sends the communication packets to a destination address described in the communication packets with reference to its communication path information, in which case the default gateway specifies the default destination of the communication packets, which is selected when the communication packets do not indicate a terminal to which the communication packets are transmitted (adjacent terminal).  
         [0000]     ( 102 )  
         [0063]     Each base station  11  references the communication path information TABLE (ST-x) (x=A, B, . . . ) contained therein as required, and advertises its address to all mobile terminals  37  accommodated in this base station  11  through broadcasting, multicasting or unicasting.  
         [0000]     ( 103 )  
         [0064]     The communication path setting function  43  of each mobile terminal  37 , which has received the advertisement of the address from the base station  11 , references the address included in the advertisement, and also references the communication path information contained therein to select from adjacent terminals an adjacent terminal which should be assigned to be the destination for transmitting the communication packets to the advertised address, and sets this adjacent terminal as a default gateway.  
         [0065]     For example, when the mobile terminal A  37   m  references the communication path information contained therein to detect, as a result, that a mobile terminal B  37   n  is an adjacent terminal for enabling the communication packets to arrive at the base station A  11   h,  the mobile terminal A  37   m  sets this mobile terminal B  37   n  as a default gateway.  
         [0066]     If the mobile terminal B  37   n  also makes a similar setting (setting the base station A  11   h  as a default gateway which is the destination to which the communication packets should be sent), the communication packets are transmitted from the mobile terminal A  37   m  and arrive at the base station A  11   h  through the mobile terminal B  37   n.    
         [0067]     Since each mobile terminal repeatedly sets a default gateway (for example, on a periodic basis) for sending communication packets to the base station as described above, the mobile terminal, even distanced by two hops or more from the base station, can send communication packets to the Internet gateway  3  to access the Internet.  
         [0068]     When a mobile terminal receives advertisements from a plurality of base stations  11 , the mobile terminal appropriately references at least one of combinations among the radio field strength from each of the base stations  11 , the number of hops from each of the base stations  11 , the communication performance up to each of the base stations  11  (one or more combinations among a delay, throughput, packet loss rate, jitter and the like), the distance from each of the base stations  11  to the mobile terminal, the number of hops to the base station management terminal  1 , and the communication performance up to the base station management terminal  1  (one or more combinations among a delay, throughput, packet loss rate, jitter and the like) to select an optimal base station  11  for sending the communication packets to the base station management terminal  1 .  
         [0069]     The mobile terminal  37  registers a selected base station  11  as a default gateway for sending communication packets to the base station management terminal  1  using the communication path setting function  43 .  
         [0000]     5. Method of Accessing Internet from Mobile Terminal in Non-Hierarchical Mobile Terminal Management Method  
         [0070]     Referring to  FIG. 6 , description will be made on a method for enabling a mobile terminal A  37   q  to send communication packets to an Internet gateway in the multi-hop mode to access the Internet from the mobile terminal A  37   q , even if the mobile terminal A  37   q  is located out of the coverage area of a base station A  11   j.    
         [0071]     In  FIG. 6 , the base stations  11  and mobile terminals  37  are managed by the management method illustrated in  FIG. 4 . With the management method illustrated in  FIG. 4 , the base station management terminal  1 , base stations  11 , and mobile terminals  37  have communication path information  67  (TABLE (Adm)),  69  (TABLE (ST-x) (x=A, B, C, . . . )),  71  (TABLE (MMN-x) (x=A, B, C, . . . ), respectively.  
         [0000]     &lt;Internet Accessing Method&gt; 
         [0000]     ( 401 )  
         [0072]     The base station management terminal  1  references the communication path information TABLE (Adm)  73  contained therein as required to advertise its own address to the base stations  11  and mobile terminals  37  through broadcasting, multicasting, or unicasting.  
         [0000]     ( 402 )  
         [0073]     Each of the mobile terminals  37  and each of the base stations  11  sets an adjacent terminal for sending communication packets to the base station management terminal having the address included in the advertisement as a default gateway.  
         [0074]     For example, when the mobile terminal A  37   q  detects that a mobile terminal B  37   p  is an adjacent terminal for enabling the communication packets to arrive at the base station management terminal  1  with reference to the communication path information contained therein, the mobile terminal A  37   q  sets this mobile terminal B  37   p  as a default gateway.  
         [0075]     Since the mobile terminal B  37   p  and base station A  11   j  also make a similar setting (for setting a default gateway for enabling the communication packets to arrive at the base station management terminal  1 ), the communication packets can be transmitted from the mobile terminal A  37   q  to the base station management terminal  1  through the mobile terminal B  37   p  and base station A  11   j.    
         [0076]     When all the mobile terminals and base stations repeatedly set a default gateway (for example, on a periodic basis) for enabling communication packets to arrive at the base station management terminal  1 , a mobile terminal, which is distanced even by several hops from the base station management terminal  1 , can send communication packets for accessing the Internet, and can therefore access the Internet.  
         [0000]     6. Method of Communicating between Mobile Terminals in Multi-Hop Mode through Base Station, Wired Network, and Mobile Terminal in Hierarchical Mobile Terminal Management Method  
         [0077]     Referring to  FIG. 7 , description will be made on a method of enabling communications between mobile terminals  37  in the multi-hop mode through the base station  11 , Internet  48 , and mobile terminal  37 .  
         [0078]     Assume in  FIG. 7  that the base stations  11  and mobile terminals  37  are managed by the management method illustrated in  FIG. 3 .  
         [0000]     &lt;Precondition&gt; 
         [0000]     ( 201 )  
         [0079]     Each of the base stations  11  has previously set the base station management terminal  1  having the Internet gateway function  3  as a default gateway.  
         [0000]     ( 202 )  
         [0080]     Each of the base stations  11  references the communication path information TABLE (ST-x) (x=A, B, . . . ) contained therein, and advertises its own address to all mobile terminals  37  managed by the base station itself through broadcasting, multicasting, or unicasting.  
         [0000]     ( 203 )  
         [0081]     Each of the mobile terminals  37  which have received the advertisement of the address from the base station  11  references the address included in the advertisement, and further references the communication path information contained therein, if necessary, to set an adjacent terminal for sending communication packets to this address as a default gateway.  
         [0082]     In an ad hoc network, since an outgoing path is not necessarily the same as an incoming path between two terminals, the originator of an advertised address is not necessarily assigned to be a default gateway, so that every mobile terminal must reference the communication path information contained therein to set a default gateway.  
         [0000]     &lt;Communicating Method&gt; 
         [0083]     Description will be made on a communication made between a mobile terminal C (MN-C)  37   u  and a mobile terminal A (MN-A)  37   s  in  FIG. 7 .  
         [0084]     When the mobile terminal C (MN-C)  37   u  transmits communication packets destined to the mobile terminal A (MN-A)  37   s , the mobile terminal C (MN-C)  37   u  references a default gateway setting item contained therein to confirm that the default gateway is a base station B  11   m , and then transmits the communication packets to the base station B  11   m . Upon receipt of the communication packets from the mobile terminal C (MN-C)  37   u , the base station B (ST-B)  11   m  references a default gateway setting item contained therein to confirm that the default gateway is the base station management terminal (Adm)  1 , and transmits the communication packets to the base station management terminal (Adm)  1 . In this way, the communication packets are originated from the mobile terminal C (MN-C)  37   u  and arrive at the base station management terminal  1  ( 204 ).  
         [0085]     Upon receipt of the communication packets, the base station management terminal (Adm)  1  references the communication path information TABLE(Adm) contained therein for a communication path to the mobile terminal A(MN-A)  37   s  to confirm that an adjacent terminal for sending the communication packets to the mobile terminal A(MN-A)  37   s  is a base station A(ST-A)  111 . Then, the base station management terminal (Adm)  1  transmits the communication packets to the base station A(ST-A)  111 .  
         [0086]     Further, the base station A(ST-A)  111 , upon receipt of the communication packets, references the communication path information TABLE(ST-A) contained therein for a communication path to the mobile terminal A(MN-A)  37   s  to confirm that an adjacent terminal for sending the communication packet to the mobile terminal A(MN-A)  37   s  is a mobile terminal B(MN-B)  37   t . Then, the base station A(ST-A)  111  transmits the communication packets to the mobile terminal B(MN-B)  37   t.    
         [0087]     Further, upon receipt of the communication packets, the mobile terminal B(MN-B)  37   t  references the communication path information TABLE(MN-B) contained therein for a communication path to the mobile terminal A(MN-A)  37   s , and transmits the communication packets to the mobile terminal A(MN-A)  37   s . In this way, the communication packets arrive at the mobile terminal A(MN-A)  37   s  from the base station management terminal  1 . ( 205 )  
         [0088]     The transmission of communication packets from the mobile terminal C(MN-C)  37   u  to the mobile terminal A(MN-A)  37   s  (return way) is performed in a similar manner to implement communications between the mobile terminal A(MN-A) and the mobile terminal C(MN-C).  
         [0089]     In this way, communications can be made between mobile terminals in the multi-hop mode through the base station  11 , Internet  48 , and mobile terminal  37 .  
         [0090]     A plurality of candidate communication paths can exist for communications between the mobile terminal A(MN-A)  37   s  and the mobile terminal C(MN-C)  37   u , such as a direct communication, or a multi-hop based radio-only communication path, as well as the communication path through the base station  11 , Internet  48 , and mobile terminal  37 . In this event, an appropriate communication path may be determined in accordance with the type of a communication path (whether it consists only of a radio communication path or includes a wired communication path), the number of times of hopping until a destination node, the amount of a remaining battery in a communication relay terminal, the radio field strength between the terminals in communication, the communication performance such as a delay time between the terminals in communication, throughput, packet loss rate, and jitter, and so forth.  
         [0000]     7. Method of Communicating between Mobile Terminals in Multi-Hop Mode through Base Station, Wired Network, and Mobile Terminal in Non-Hierarchical Mode Terminal Management Method  
         [0091]     Referring to  FIG. 8 , description will be made on a method which enables communications between mobile terminals in the multi-hop mode through the base station  11 , Internet  48 , and mobile terminal  37 .  
         [0092]     In  FIG. 8 , the base stations  11  and mobile terminals  37  are managed by the management method illustrated in  FIG. 4 . With the management method illustrated in  FIG. 4 , the base station management terminal  1 , base stations  11 , and mobile terminals  37  have communication path information  67  (Table(Adm)),  69  (TABLE(ST-x) (x=A, B, . . . )),  71  (TABLE(MN-x) (x=A, B, C, . . . )), respectively.  
         [0000]     &lt;Communication Method&gt; 
         [0093]     A communication made between a mobile terminal C(MN-C)  37   x  and a mobile terminal B(MN-B)  37   w  in  FIG. 8  will be given as an example.  
         [0094]     When the mobile terminal C(MN-C)  37   x  transmits communication packets to the mobile terminal B(MN-B)  37   w , the base station management terminal  1 , base station A(ST-A), base station B(ST-B), and mobile terminal A(MN-A) sequentially forward the communication packets to adjacent terminals for sending the communication packets to the mobile terminal B(MN-B)  37   w  which is set in the respective communication path information TABLE(Adm), TABLE(ST-A), TABLE(ST-B), and TABLE(MN-A), thereby sending the communication paths to the mobile terminal B(MN-B)  37   w.    
         [0095]     Likewise, when the mobile terminal B(MN-B)  37   w  transmits communication packets to the mobile terminal C(MN-C)  37   x , the communication packets arrive at the mobile terminal C(MN-C)  37   x.    
         [0096]     In this way, the multi-hop based communications can be accomplished between mobile terminals through the base station  11 , Internet  48 , and mobile terminal  37 .  
         [0097]     A plurality of candidate communication paths can exist for communications between the mobile terminal B(MN-B)  37   w  and the mobile terminal C(MN-C)  37   x , such as a direct communication, or a multi-hop based radio-only communication path, as well as the communication path through the base station  11 , Internet  48 , and mobile terminal  37 . In this event, an appropriate communication path may be determined in accordance with the type of a communication path (whether it consists only of a radio communication path or includes a wired communication path), the number of times of hopping until a destination node, the amount of a remaining battery in a communication relay terminal, the radio field strength between the terminals in communication, the communication performance such as a delay time between the terminals in communication, throughput, packet loss rate, and jitter, and so forth.  
         [0098]     It should be further understood by those skilled in the art that although the foregoing description has been made on embodiments of the invention, the invention is not limited thereto and various changes and modifications may be made without departing from the spirit of the invention and the scope of the appended claims.