Abstract:
In a system that transmits and receives data through a high-level relay in a mesh ad hoc wireless network including the high-level relay and ad hoc wireless nodes, an increase in data traffic to the high-level relay, and the ad hoc wireless nodes in proximity to the high-level relay, a reduction in use efficiency of a wireless bandwidth of the high-level relay and in the proximity to the high-level relay in association with the increase in the data traffic, and a reduction in the efficiency of an entire mesh ad hoc wireless network are prevented. In the mesh ad hoc wireless network having the high-level relay, and the ad hoc wireless nodes each having a smart meter function unit, meter reading information collection implemented by the high-level relay is delegated to the ad hoc wireless nodes from the high-level relay by one hop, and the use efficiency of the wireless bandwidth in proximity to the high-level relay is improved.

Description:
CLAIM OF PRIORITY 
       [0001]    The present application claims priority from Japanese patent application JP 2012-049191 filed on Mar. 6, 2012, the content of which is hereby incorporated by reference into this application. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to an ad hoc network system and a meter reading information collecting method, and more particularly to an ad hoc network system and a meter reading information collecting method, which collect meter reading information in a mesh ad hoc wireless network. 
         [0004]    2. Background Art 
         [0005]    In recent years, there has been proposed a system in which a mesh ad hoc wireless network is formed as constituent elements of a smart meter, and meter reading information and control information of the smart meter are communicated on the mesh ad hoc wireless network. 
         [0006]    As a background art of this technical field, there is RFC3626 “Optimized Link State Routing Protocol (OLSR)”. This document discloses a technique in which each of wireless nodes notifies a neighborhood of routing information provided in the subject wireless node in a broadcast packet called “annunciation message” whereby each node in the mesh ad hoc wireless network autonomically constructs a channel. 
         [0007]    On the other hand, there is Japanese Unexamined Patent Application Publication No. 2001-237764. This publication discloses that one connectable wireless station in which the number of hops obtained by hop number information is smallest is selected as a high-level destination wireless station, and a signal transfer unit transfers a transmit signal or a signal received from a child wireless station to the high-level destination wireless station, or transfers the signal to abase station if the connectable wireless station can be connected directly to the base station. With the above configuration, the publication defines a technique of optimizing the channel of the mesh ad hoc wireless network in which the base station and the child wireless station autonomically select the channel small in the number of hops, determine the channel small in the number of hops as an optimum channel, and transmit a packet. 
         [0008]    Also, there is JP-A-2006-211375. This publication defines a communication means that implements the channel selection taking the number of hops as well as a processing load of the node into account to reduce a transmission delay and a packet loss on the channel. 
         [0009]    There is JP-A-2006-50371. This publication discloses a data transmitting method that includes a first step of transmitting data from a first terminal to a second terminal with at least another terminal as a data relay terminal, a second step of transmitting a control message for controlling the amount of transmission of relay data from the data relay terminal to the first terminal, and a third step of changing a transmission mode of data addressed to the second terminal according to the contents of the control message by the first terminal. This document defines a data traffic control technique in the ad hoc wireless network. 
       SUMMARY OF THE INVENTION 
       [0010]    JP-A-2001-237764 defines an autonomic channel constructing technique depending on the number of hops. JP-A-2006-211375 defines an improved channel constructing technique by adding information on the processing load of the node to the autonomic channel construction. JP-A-2006-50371 defines a communication further high in reliability in a system regulating the traffic. However, originally, from the viewpoint of the property of the network that finally collects the information into the high-level relay, problems that the trial number of acquiring wireless transmission rights in proximity to the high-level relay, and the usage of a wireless bandwidth are increased cannot be avoided, and a problem that a communication quality and reliability in proximity to the high-level relay are lessened still remains. 
         [0011]    Also, RFC3626 “Optimized Link State Routing Protocol (OLSR)” defines the technique of autonomically constructing the channel of the ad hoc network. JP-A-2001-237764, JP-A-2006-211375, and JP-A-2006-50371 define the technique of selecting the optimum channel so as to lessen a network load in autonomic construction. In the ad hoc wireless network for collecting the meter reading information of the smart meter, even in proximity to the high-level relay and even in the wireless node arranged in a terminal, the bandwidth of the wireless band is not changed, but on the system where each node selects the high-level relay as a destination, as a result that traffic from the respective wireless nodes is collected in proximity to the high-level relay, an increase in the traffic in proximity to the high-level relay, an increase in the trial number of acquiring the wireless transmission rights, and an increase in wireless bandwidth use rate are unavoidable. A problem that the use efficiency of the wireless bandwidth in proximity to the high-level relay is remarkably reduced remains. 
         [0012]    Also, in a multicast packet in the ad hoc network, an ad hoc wireless node that receives the multicast packet can implement transfer availability determination only under a hop number control, and the number of packets is increased according to the number of forwarding destination nodes, resulting in a problem that the wireless bandwidth use rate is increased. 
         [0013]    In view of the above circumstances, an object of the present invention is to provide an ad hoc wireless network system and a meter reading information collecting method, which prevent the efficiency of the wireless bandwidth from being lessened in proximity to a high-level relay in a system that collects data into the high-level relay in a mesh ad hoc wireless network including a plurality of high-level relays and a plurality of ad hoc wireless nodes. 
         [0014]    Another object of the present invention is to realize a communication system that improves a wireless bandwidth use efficiency of a node having a close electric wave in a system that conducts a multicast communication over the network. 
         [0015]    In order to solve the above problem, for example, configurations defined in the claims are applied. 
         [0016]    The present invention includes a plurality of solutions to the above problem, and one example thereof is that a part or all of meter reading information collection of a high-level relay is delegated to a low-level ad hoc wireless node. Also, a delegation relationship between the high-level relay and the low-level ad hoc wireless node to which the meter reading information collection is delegated is managed by a group ID. 
         [0017]    The multicast packet in the ad hoc network is added with control information for each of the group IDs, and an example thereof is that the ad hoc wireless node belonging to a group indicated by the group ID transfers a multicast packet of the group ID, and discards a multicast packet of no group ID. 
         [0018]    According to the first solving means of the present invention, there is provided an ad hoc network system, comprising: 
         [0019]    a plurality of ad hoc wireless nodes each having a smart meter function unit that measures and transmits meter reading information; and 
         [0020]    a high-level relay that receives the meter reading information from the ad hoc wireless nodes, 
         [0021]    wherein 
         [0022]    the high-level relay selects one or a plurality of ad hoc wireless nodes, of one hop from the subject high-level relay as an alternate relay, 
         [0023]    the high-level relay groups the ad hoc wireless nodes that communicate with each other through the alternate relay, and 
         [0024]    the high-level relay transmits an alternate relay request including identification information of the grouped ad hoc wireless nodes to the alternate relay, 
         [0025]    the alternate relay transmits identification information of the subject alternate relay to the grouped ad hoc wireless nodes, 
         [0026]    each of the grouped ad hoc wireless nodes transmits the meter reading information measured by the smart meter function unit to the alternate relay, and 
         [0027]    the alternate relay receives the respective meter reading information from the grouped plurality of ad hoc wireless nodes, and transmits the received respective meter reading information and the meter reading information measured by a smart meter storage unit of the subject alternate relay to the high-level relay in a lump. 
         [0028]    According to the second solving means of the present invention, there is provided a meter reading information collecting method in an ad hoc network system, comprising: 
         [0029]    a plurality of ad hoc wireless nodes each having a smart meter function unit that measures and transmits meter reading information; and 
         [0030]    a high-level relay that receives the meter reading information from the ad hoc wireless nodes, 
         [0031]    wherein 
         [0032]    the high-level relay selects one or a plurality of ad hoc wireless nodes, of one hop from the subject high-level relay as an alternate relay, 
         [0033]    the high-level relay groups the ad hoc wireless nodes that communicate with each other through the alternate relay, and 
         [0034]    the high-level relay transmits an alternate relay request including identification information of the grouped ad hoc wireless nodes to the alternate relay, 
         [0035]    the alternate relay transmits identification information of the subject alternate relay to the grouped ad hoc wireless nodes, 
         [0036]    each of the grouped ad hoc wireless nodes transmits the meter reading information measured by the smart meter function unit to the alternate relay, and 
         [0037]    the alternate relay receives the respective meter reading information from the grouped plurality of ad hoc wireless nodes, and transmits the received respective meter reading information and the meter reading information measured by a smart meter storage unit of the subject alternate relay to the high-level relay in a lump. 
         [0038]    It is possible, according to the present invention, to provide an ad hoc wireless network system and a meter reading information collecting method, which prevent the efficiency of the wireless bandwidth from being lessened in proximity to a high-level relay in a system that collects data into the high-level relay in a mesh ad hoc wireless network including a plurality of high-level relays and a plurality of ad hoc wireless nodes. 
         [0039]    In addition, it is possible, according to the present invention, to realize a communication system that improves a wireless bandwidth use efficiency of a node having a close electric wave in a system that conducts a multicast communication over the network. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0040]      FIG. 1  is a system configuration diagram of a mesh ad hoc wireless network; 
           [0041]      FIG. 2  is a functional block diagram of a high-level relay; 
           [0042]      FIG. 3  is a functional block diagram of an ad hoc wireless node; 
           [0043]      FIG. 4  is a link table of the high-level relay and the ad hoc wireless node; 
           [0044]      FIG. 5  is a routing table of the high-level relay and the ad hoc wireless node; 
           [0045]      FIG. 6  is an alternate relay management table of the high-level relay; 
           [0046]      FIG. 7  is a diagram of processing of selecting an alternate relay, and grouping the affiliation ad hoc wireless nodes; 
           [0047]      FIG. 8  is a sequence diagram of designating the alternate relay, and collecting the meter reading information; 
           [0048]      FIGS. 9A and 9B  are diagrams of frame formats of an alternate relay request and an alternate relay response; 
           [0049]      FIG. 10  is a diagram of a frame format of a group ID notification; 
           [0050]      FIG. 11  is a diagram of a frame format of the meter reading information; 
           [0051]      FIGS. 12A and 12B  are diagrams of frame formats of a meter reading completion notification and a meter reading completion response; 
           [0052]      FIGS. 13A ,  13 B, and  13 C are diagrams of frame formats of a meter reading information acquisition request and a meter reading completion acquisition response; 
           [0053]      FIG. 14  is a sequence diagram configuring a link table and a routing table by an annunciation message notification; 
           [0054]      FIGS. 15A and 15B  are diagrams of formats of an annunciation message; 
           [0055]      FIG. 16  is a diagram of an example of the annunciation message; 
           [0056]      FIG. 17  is a diagram of an example of the annunciation message; 
           [0057]      FIG. 18  is a diagram of an example of the annunciation message; 
           [0058]      FIG. 19  is a diagram of an example of the annunciation message; 
           [0059]      FIG. 20  is a diagram of an example of the annunciation message; 
           [0060]      FIG. 21  is a sequence diagram of a multicast communication; 
           [0061]      FIG. 22  is a diagram of a format of a multicast message; 
           [0062]      FIG. 23  is a diagram of an example of the multicast message; 
           [0063]      FIG. 24  is a diagram of an example of the multicast message; 
           [0064]      FIG. 25  is a diagram of an example of the multicast message; and 
           [0065]      FIG. 26  is a diagram of an example of the multicast message. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0066]    Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The substantially same portions are denoted by identical reference numbers, and their description will not be repeated. 
       (Hardware Configuration and Table Configuration) 
       [0067]    A mesh ad hoc wireless network system will be described with reference to  FIG. 1 . Referring to  FIG. 1 , at least one high-level relay  1   n  (n=0, 1, 2, . . . ) and a plurality of ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) configure a mesh ad hoc wireless network in a wireless communication system conforming to the wireless communication standard defined by, for example, IEEE802.11. 
         [0068]    A method of configuring the mesh ad hoc wireless network in the high-level relay  1   n  (n=0, 1, 2, . . . ) and the ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) can be realized by a mechanism that informs a neighborhood of information on its routing table, with the use of an annunciation message packet by broadcast, for example, and autonomically configures a link table and a routing table, as disclosed in RFC3626 “Optimized Link State Routing Protocol (OLSR)”. 
         [0069]    A high-level relay  10  communicates directly with ad hoc wireless nodes  20 ,  21 , and  22 . The high-level relay  10  conducts a multi-hop communication with ad hoc wireless nodes  23 ,  24 ,  25 , and  26  through the ad hoc wireless node  20 . The high-level relay  10  relays, for example, meter reading information from the ad hoc wireless node to a meter reading data collection server. 
         [0070]    The configuration and the function of the high-level relay  10  will be described with reference to  FIG. 2 . The high-level relay  10  includes, for example, an internal storage unit (hereinafter referred to as “internal storage”)  100 , an ad hoc network control unit  101 , a wireless communication unit  102 , a relay unit  103 , a high-level network control unit  104 , a high-level network communication unit  105 , and a multi-cast control unit  93 . 
         [0071]    On the internal storage  100  are disposed at least a link table  1000  that manages the ad hoc wireless nodes that communicate with the high-level relay  10  by one hop, a routing table  1001  that manages the ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) that conduct a communication with the high-level relay  10  by one hop or multi-hop, and an alternate relay management table  1002  that manages the ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) which are selected as alternate relays to which the high-level relay  10  delegates meter reading information collection. 
         [0072]    Also, the high-level relay  10  includes an ad hoc network control unit  101 , and includes, as a part of the ad hoc network control unit  101 , an annunciation message control unit  1010  that updates information on the link table and the routing table, and an alternate relay management unit  1011  that selects and manages the alternate relay. The ad hoc network control unit  101  communicates with the ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) present on the ad hoc network through the wireless communication unit  102  that controls a physical media access. 
         [0073]    After receiving the meter reading information received from an ad hoc network  40  through the wireless communication unit  102 , the high-level relay  10  transmits the meter reading information to a high level network  50  from the high-level network communication unit  105  through the ad hoc network control unit  101 , the relay unit  103 , and the high-level network control unit  104 . 
         [0074]    The high-level relay  10  includes the multi-cast control unit  93  that conducts transmission and reception control of the multi-cast, and conducts multi-cast communication on the ad hoc wireless network through the ad hoc network control unit  101  according to the multicast message. 
         [0075]    The configuration and the function of the ad hoc wireless node  20  will be described with reference to  FIG. 3 . The ad hoc wireless node  20  includes the internal storage unit (hereinafter referred to as “internal storage”)  100 , the ad hoc network control unit  101 , the wireless communication unit  102 , a smart meter function unit  203 , and the multicast control unit  93 . 
         [0076]    On the internal storage  100  are disposed information on at least the link table  1000  that manages other ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) that communicate with the subject ad hoc wireless node by one hop, and the high-level relays  1   n  (n=0, 1, 2, . . . ) that communicate with the subject ad hoc wireless node by one hop, the routing table  1001  that manages the ad hoc wireless nodes and the high-level relay  10  which conduct a communication with each other by one hop or a multi-hop from the ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ), an alternate relay information management table  1003  that manages the high-level alternate relay, and a meter reading information holding table  1004  that temporarily buffers the meter reading information of the ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) put under the control, which is used when the ad hoc wireless node is selected as the alternate relay. 
         [0077]    Also, the ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) each have the ad hoc network control unit  101 , and includes the annunciation message control unit  1010  that updates information on the link table and the routing table, and the alternate relay management unit  1011  that selects and manages the alternate relay, as a part of the ad hoc network control unit  101 . 
         [0078]    The ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) have the smart meter function unit  203 , and includes a meter reading control unit  2030  and a meter  2031 , which implement the meter reading of the smart meter. 
         [0079]    The meter reading control unit  2030  periodically reads a meter reading value, and transmits the meter reading information to the ad hoc network  40  with the high-level relay  1   n  (n=0, 1, 2, . . . ) or the alternate relay as a final destination, through the ad hoc network control unit  101  and the wireless communication unit  102 . In this example, an electric power can be used as an example of the meter reading information, but appropriate measurement data may be used apart from the electric power. Also, plural pieces of measurement data may be included. 
         [0080]    The ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) each have the multi-cast control unit  93  that controls transmission and reception of the multicast, and conduct a multicast communication through the ad hoc network control unit  101  on the ad hoc wireless network according to a multicast message. 
         [0081]    A description will be given of the link table  1000  which is held within the internal storage  100  of the high-level relay  10 , and the link table  1000  which is held within the internal storage  100  of the ad hoc wireless node  20 , with reference to  FIG. 4 . The link tables  1000  manage the respective nodes of one hop from their devices. The link table  1000  has a node ID  10000  of the node of one hop from at least its devices, and has a parameter for evaluating the communication quality of the link in correspondence with the node ID  10000 , as an example, has respective information of a electric wave reception intensity  10001 , and identification information of a bidirectional link  10002  indicating whether the link is bidirectional, or not. As illustrated in  FIG. 3 , the node ID  10000  is, for example, an identifier that uniquely determines the ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) and the high-level relay  1   n  (n=0, 1, 2, . . . ) such as an MAC address. 
         [0082]      FIG. 5  illustrates the routing table  1001  which is held within the internal storage  100  of the high-level relay  10 , and the routing table  1001  which is held within the internal storage  100  of the ad hoc wireless node  20 . The routing table  1001  has information on the ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) that communicates with the high-level relay  10  by one hop or a multi-hop. The information internally held includes at least a final destination node ID  10010 , and a closest node ID  10011 . The final destination node ID  10010  and the closest node ID  10011  are, for example, identifiers that uniquely determine the ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) of the final destination and the high-level relay  1   n  (n=0, 1, 2, . . . ), such as an MAC address. The plurality of closest node IDs  10011  can be held for one final destination node ID  10010 . In an example of  FIG. 5 , three closest node IDs  10011  are held for one final destination node ID. The closest node ID which is one element of the routing table  1001  of the high-level relay  10  and the ad hoc wireless node  20  is present as the entry within the link table  1000 . 
         [0083]    When the high-level relay  10  and the ad hoc wireless node  20  transmit data to the final destination node, one node is selected from the plurality of closest node IDs  10011  corresponding to the final destination node ID  10010 , and the data is transmitted to the closest node ID. As one example, among the corresponding plural closest nodes, the closest node whose electric wave reception intensity  10001  is higher than a predetermined reference, and which establishes a bidirectional link  10002  is selected preferentially, as exemplified by  FIG. 4 . The node that receives the data selects the closest node through the same operation, and propagates the data to the final destination by multi-hop. 
         [0084]    The configuration of the link table  1000  exemplified in  FIG. 4  and the routing table  1001  exemplified in  FIG. 5  can be realized by an annunciation message mutual communication between the high-level relay and the ad hoc wireless node, and between the ad hoc wireless node and the ad hoc wireless node, as disclosed in RFC3626 “Optimized Link State Routing Protocol (OLSR)”. In the high-level relay  10 , the construction of the link table  1000  exemplified in  FIG. 4 , and the routing table  1001  exemplified in  FIG. 5  is realized by the annunciation message control unit  1010  which is a part of the ad hoc network control unit  101  illustrated in  FIG. 2 . In the ad hoc wireless node  20 , the configuration functions of the link table  1000  exemplified in  FIG. 4  and the routing table  1001  exemplified in  FIG. 5  are realized by the annunciation message control unit  1010  which is a part of the ad hoc network control unit  101  illustrated in  FIG. 3 . 
         [0085]    Also, another example of the configurations of the link table  1000  and the routing table  1001  which are realized by the annunciation message control unit  1010  will be described with reference to  FIGS. 14 and 15 .  FIG. 15  illustrates a format of an annunciation message  80 . 
         [0086]    The annunciation message  80  includes a closest node ID  800 , a closest source node ID  801 , a final destination node ID  802 , a source node ID  803 , an annunciation message code  804 , number of routings  805 , and routing information  806 . 
         [0087]    The closest node ID  800  holds a broadcast address, the closest source node ID  801  holds the high-level relay  1   n  (n=0, 1, 2, . . . ) which is the closest source, or a node ID of the ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ). The final destination node ID  802  holds a broadcast address, the source node ID  803  holds the high-level relay  1   n  (n=0, 1, 2, . . . ) which is a source, or the node ID of the ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ). The annunciation message code  804  holds a predetermined integer value which indicates an annunciation message. The number of routings  805  holds the number of routings (the number of routing information) included in the annunciation message  80 , and the routing information  806  holds the routing information of the source. The above-mentioned integer value held by the message may be appropriate identification information other than the integer value. The same is applied to the messages and data formats which will be described below. 
         [0088]    As illustrated in  FIG. 15B , routing information  806  holds the routing enable node ID  8060  and a number of hops  8061 . The routing information  806  holds a number of routing enable nodes  807  which is held within the routing table  1001  by the source node. The routing enable node ID  8060  of the number of routing enable nodes  806  is exemplified by the final destination node ID  10010  illustrated in  FIG.5 , and the number of hops  8061  is exemplified by a number of hops  10014  illustrated in  FIG. 5 . 
         [0089]    The details of the operation will be described with reference to  FIGS. 14 ,  16 ,  17 ,  18 ,  19 ,  20 , and  21 . In this example, the ad hoc wireless node  20  comes close to, and can communicate directly with the high-level relay  10  and the ad hoc wireless node  23 . 
         [0090]    In an initial state, no entry is present in the link table  1000  and the routing table  1001  of the high-level relay  10 , the ad hoc wireless node  20 , the ad hoc wireless node  23 , 
         [0091]    The high-level relay  10  transmits an annunciation message  8000  to one hop from the high-level relay  10 .  FIG. 16  illustrates an example of the annunciation message  8000 . 
         [0092]    As the contents of the annunciation message  8000 , a closest destination node ID  80000  has FF:FF:FF:FF:FF:FF indicative of the broadcast, a closest source node ID  80001  has a node ID  90  of the high-level relay  10  which is a source node. A final destination node ID  80002  has FF:FF:FF:FF:FF:FF indicative of the broadcast. A source node ID  80003  has the node ID  90  of the high-level relay  10  which is a source node. An annunciation message code  80004  has a predetermined integer value (0 in the example of  FIG. 16 ) indicative of an annunciation message. A number of routings  80005  has 0 because no routing information is present in the initial state. Because no routing information is provided, the routing information  806  illustrated in  FIG. 15  is not included in the annunciation message  8000 . 
         [0093]    The ad hoc wireless node  20  that receives the annunciation message  8000  recognizes that the high-level relay  10  is present in proximity to the ad hoc wireless node  20 . As one entry of the link table  1000  of itself, the node ID  90  of the high-level relay  10  which is the source is set for the node ID  10000 . The electric wave reception intensity when receiving the electric wave is registered in the electric wave reception intensity  10001 , and for example, 0 is set for a bidirectional link  10002 . The ad hoc wireless node  20  that receives the annunciation message  8000  sets the node ID  90  of the high-level relay  10  of the source for the final destination node ID  10010  of the routing table  1001  of itself, sets the node ID  90  of the high-level relay  10  of the source for the closest node ID  10011 , and 1 is set for the number of hops  10014  because the annunciation message  8000  is received directly from the high-level relay  10 . 
         [0094]    The ad hoc wireless node  20  transmits an annunciation message  8001  to one hop from the ad hoc wireless node  20 .  FIG. 17  illustrates an example of the annunciation message  8001 . As the contents of the annunciation message  8001 , a final destination node ID  80010  has FF:FF:FF:FF:FF:FF indicative of the broadcast. A closest source node ID  80011  has a node ID  91  of the ad hoc wireless node  20  which is a source node. A final destination node ID  80012  has FF:FF:FF:FF:FF:FF indicative of the broadcast. A source node ID  80013  has the node ID  91  of the ad hoc wireless node  20  which is a source node. An annunciation message code  80014  has a predetermined integer value representing that the annunciation message is present (0 in the illustration of  FIG. 17 ). A number of routings  80015  has the number of entries of the routing table  1000  (1 in this case) configured at the time of receiving the annunciation message  8000 . A node ID  80016  has the node ID  90  of the high-level relay  10  which is one information of the routing table  1000  configured at the time of receiving the annunciation message  8000 . A number of hops  80017  has the number of hops of the high-level relay  10  which is one information of the routing table  1000  configured at the time of receiving the annunciation message  8000 . 
         [0095]    The high-level relay  10  that receives the annunciation message  8001  recognizes that the ad hoc wireless node  20  is present in proximity to the high-level relay  10 , and registers the ad hoc wireless node ID  91  of the source in the node ID  10000  as one entry of the link table  1000  of itself. The high-level relay  10  also registers the electric wave reception intensity at the time of reception in the electric wave reception intensity  10001 . Also, in the high-level relay  10 , the node ID  80016  which is a part of the routing information of the annunciation message  8001  is the node ID  90  of the high-level relay  10  per se, and the number of hops  80017  is 1. Therefore, 1 (a value indicating that a bidirectional link is present) is set for the bidirectional link  10002  of the link table entry. 
         [0096]    In the high-level relay  10  that receives the annunciation message  8001 , the node ID  91  of the ad hoc wireless node  20  of the source is set for the final destination node ID  10010  of the routing table  1001  of itself. The node ID  91  of the ad hoc wireless node  20  is set for the closest node ID  10011 , and 1 is set for the number of hops  10014  because the annunciation message  8001  is received directly from the ad hoc wireless node  20 . 
         [0097]    The annunciation message  8001  is also received by the ad hoc wireless node  23 . The ad hoc wireless node  23  recognizes that the ad hoc wireless node  20  is present in proximity to the ad hoc wireless node  23 , and as one entry of the link table  1000  of itself, registers the ad hoc wireless node ID  91  of the source in the node ID  10000 , and the electric wave reception intensity at the time of reception in the electric wave reception intensity  10001 . Also, the ad hoc wireless node  23  sets 0 for the bidirectional link  10002  of the link table entry because the node ID  80017  which is a part of the routing information of the annunciation message  8001  is not a node ID  92  of the received ad hoc wireless node  23  per se. 
         [0098]    The ad hoc wireless node  23  that receives the annunciation message  8001  sets, as one entry of the routing table  1001  of itself, the node ID  91  of the ad hoc wireless node  20  of the source for the final destination node ID  10010 . Also, the ad hoc wireless node  23  sets the node ID  91  of the ad hoc wireless node  20  for the closest node ID  10011 , and sets 1 for the number of hops  10014  because the annunciation message  8001  is received directly from the ad hoc wireless node  20 . Also, the ad hoc wireless node  23  sets, as another entry, the node ID  80016  of the routing information for the final destination node ID  10010 . The ad hoc wireless node  23  also sets the node ID  91  of the ad hoc wireless node  20  which is a direct source of the annunciation message  8001  for the closest node ID  10011 , and sets a value obtained by adding 1 for the number of hops  80017  of the routing information. 
         [0099]    The ad hoc wireless node  23  transmits an annunciation message  8002  to one hop from the ad hoc wireless node  23 .  FIG. 18  illustrates an example of the annunciation message  8002 . As the contents of the annunciation message  8002 , a closest destination node ID  80020  has FF:FF:FF:FF:FF:FF indicative of the broadcast. A closest source node ID  80021  has the node ID  92  of the ad hoc wireless node  23  which is the source node. A final destination node ID  80022  has FF:FF:FF:FF:FF:FF indicative of the broadcast. A source node ID  80023  has the node ID  92  of the ad hoc wireless node  23  which is a source node. An annunciation message code  80024  has a predetermined integer value representing that the annunciation message is present (0 in the illustration of  FIG. 18 ). A number of routings  80025  has the number of entries of the routing table  1000  (2 in this case) configured at the time of receiving the annunciation message  8001 . A node ID  80026  has the node ID  91  of the ad hoc wireless node  20  which is one information of the routing table  1000  configured at the time of receiving the annunciation message  8001 . A number of hops  80027  has the number of hops of the node ID  91  of the ad hoc wireless node  20  which is one information of the routing table  1000  configured at the time of receiving the annunciation message  8001 . Anode ID  80028  has the node ID  90  of the high-level relay  10  which is another information of the routing table  1000  configured at the time of receiving the annunciation message  8001 . A number of hops  80029  has the number of hops of the node ID  90  of the high-level relay which is another information of the routing table  1000  configured at the time of receiving the annunciation message  8001 . 
         [0100]    The ad hoc wireless node  20  that receives the annunciation message  8002  recognizes that the ad hoc wireless node  23  is present in proximity to the ad hoc wireless node  20 , and as one entry of the link table  1000  of itself, registers the node ID  92  of the ad hoc wireless node  23  of the source in the node ID  10000 , and the electric wave reception intensity at the time of reception in the electric wave reception intensity  10001 . Also, the ad hoc wireless node  20  sets 1 for the bidirectional link  10002  of the link table entry because the node ID  80027  which is a part of the routing information of the annunciation message  8002  is the node ID  91  of the ad hoc wireless node  20  per se, and the number of hops  80028  is 1. 
         [0101]    Also, the ad hoc wireless node  20  that receives the annunciation message  8002  sets the node ID  91  of the ad hoc wireless node  23  of the source for the final destination node ID  10010  of the routing table  1001  of itself. Also, the ad hoc wireless node  20  sets the node ID  91  of the ad hoc wireless node  23  of the source for the closest node ID  10011 , and sets 1 for the number of hops  10014  because the annunciation message  8002  is received directly from the ad hoc wireless node  23 . Also, the ad hoc wireless node  20  registers the information whose node ID is not the node ID of itself among the routing information in the routing table  10001  of itself. For example, the ad hoc wireless node  20  sets, as another entry, the node ID  80028  of the routing information for the final destination node ID  10010 , sets the node ID  92  of the ad hoc wireless node  23  which is a direct source of the annunciation message  8002  for the closest node ID  10011 , and sets a value obtained by adding 1 to the number of hops  80029  of the routing information for the number of hops  10014 . 
         [0102]    The high-level relay  10  transmits an annunciation message  8003  to one hop from the high-level relay  10 .  FIG. 19  illustrates an example of the annunciation message  8003 . As the contents of the annunciation message  8003 , a closest destination node ID  80030  has FF:FF:FF:FF:FF:FF indicative of the broadcast, a closest source node ID  80031  has the node ID  90  of the high-level relay  10  which is a source node. A final destination node ID  80032  has FF:FF:FF:FF:FF:FF indicative of the broadcast. A source node ID  80033  has the node ID  90  of the high-level relay  10  which is a source node. An annunciation message code  80034  has a predetermined integer value (0 in the example of  FIG. 19 ) indicative of an annunciation message. A number of routings  80035  has the number of entries (1 in this case) of the routing table  1000  configured at the time of receiving the annunciation message  8001 . A node ID  80036  has the node ID  91  of the ad hoc wireless node  20  which is one information of the routing table  1000  configured at the time of receiving the annunciation message  8001 . A number of hops  80037  has the number of hops of the node ID  91  of the ad hoc wireless node  20  which is one information of the routing table  1000  configured at the time of receiving the annunciation message  8001 . 
         [0103]    The ad hoc wireless node  20  that receives the annunciation message  8003  searches the entry of the node ID  90  of the high-level relay  10  which is one entry registered in the routing table  1001  at the time of receiving the annunciation message  8000 , to update the electric wave reception intensity  10001  at the time of reception. The ad hoc wireless node  20  changes the bidirectional link  10002  of the link table entry to 1 because the node ID  80037  which is a part of the routing information of the annunciation message  8003  is the node ID  91  of the ad hoc wireless node  20  per se and the number of hops  80038  is 1. The ad hoc wireless node  20  that receives the annunciation message  8003  does not change the routing table because there is no change in the final destination node ID  10010  in the routing table  1000  configured at the time of receiving the annunciation message  8000 , and the node ID  80036 , and there is no change in the number of hops  10014  and the number of hops  80037 . 
         [0104]    The ad hoc wireless node  20  transmits an annunciation message  8004  to one hop from the ad hoc wireless node  20 .  FIG. 20  illustrates an example of the annunciation message  8004 . As the contents of the annunciation message  8004 , a final destination node ID  80040  has FF:FF:FF:FF:FF:FF indicative of the broadcast. A closest source node ID  80041  has the node ID  91  of the ad hoc wireless node  20  which is a source node. A final destination node ID  80042  has FF:FF:FF:FF:FF:FF indicative of the broadcast. A source node ID  80043  has the node ID  91  of the ad hoc wireless node  20  which is a source node. An annunciation message code  80044  has an integer value representing that the annunciation message is present (0 in the illustration of  FIG. 19 ). A number of routings  80045  has the number of entries (2 in this case) of the routing table  1000  configured at the time of receiving the annunciation messages  8000  and  8002 . A node ID  80046  has the node ID  90  of the high-level relay  10  which is one information of the routing table  1000  configured at the time of receiving the annunciation message  8000 . A number of hops  80047  has the number of hops of the node ID  90  of the high-level relay  10  which is one information of the routing table  1000  configured at the time of receiving the annunciation message  8000 . Anode ID  80048  and a number of hops  80049  have the respective information of the link table  1000  configured at the time of receiving the annunciation message  8002 . 
         [0105]    The high-level relay  10  that receives the annunciation message  8004  searches the entry of the node ID  91  of the ad hoc wireless node  20  which is one entry registered in the routing table  1001  at the time of receiving the annunciation message  8001 , to update the electric wave reception intensity  10001  at the time of reception. The high-level relay  10  that receives the annunciation message  8004  does not update the routing table because there is no change in the final destination node ID  10010  of the routing table  1000  configured at the time of receiving the annunciation message  8001 , and the node ID  80046 , and there is no change in the number of hops  10014  and the number of hops  80047 . 
         [0106]    The ad hoc wireless node  23  that receives the annunciation message  8004  searches the entry of the node ID  91  of the ad hoc wireless node  20  which is one entry registered in the link table  1001  at the time of receiving the annunciation message  8001 , to update the electric wave reception intensity  10001  at the time of reception. The ad hoc wireless node  23  that receives the annunciation message  8004  does not update the entry of the routing table related to the node ID  80046  because there is no change in the final destination node ID  10010  of the routing table  1000  configured at the time of receiving the annunciation message  8001 , and the node ID  80046 , and there is no change in the number of hops  10014  and the number of hops  80047 . Also, the ad hoc wireless node  23  sets, as another entry of the routing table of itself, the node ID  80048  of the routing information for the final destination node ID  10010 . Also, the ad hoc wireless node  23  sets the node ID  91  of the ad hoc wireless node  20  which is a direct source of the annunciation message  8004  for the closest node ID  10011 , and sets a value obtained by adding 1 for the number of hops  80049  of the routing information for the number of hops  10014 . 
         [0107]    Through the above procedure, the link table  1000  and the routing table  1001  are configured by the annunciation message control unit  1010  in each device. 
         [0108]    Subsequently, the configuration of the alternate relay management table  1002  will be described with reference to  FIGS. 4 ,  5 , and  6 . The alternate relay management table  1002  holds an alternate relay group ID  10020 , an alternate relay node ID  10021 , and affiliation node IDs  10022 ,  10023 . One alternate relay node ID  10021 , and the plurality of affiliation node IDs  10022 ,  10023  can be held for one alternate relay group ID  10020 . The alternate relay node ID  10021 , and the affiliation node IDs  10022 ,  10023  are each configured by, for example, an identifier that uniquely determines the ad hoc wireless nodes  2   n  (n=0, 1, 2, . . . ) and the high-level relay  1   n  (n=0, 1, 2, . . . ) such as the MAC address. 
         [0109]    The alternate relay node ID  10021  is a node ID existing in the link table  1000 . In an example of  FIG. 6 , the node ID  10000  on the link table  1000  is selected as the alternate relay node ID  10021 . The affiliation node IDs  10022  and  10023  are final destination node IDs existing on the routing table  1001 . In an example of  FIG. 6 , the affiliation node ID  10022  corresponds to the final destination node ID  10010 , and the affiliation node ID  10023  corresponds to the final destination node ID  10012 . 
         [0110]    A configuration method of the alternate relay management table  1002  will be described with reference to  FIGS. 6 and 7 . In processing  60  of extracting the link table/routing table search and the closest node ID, the high-level relay  10  (for example, alternate relay management unit  1011 , as the case may be) searches the link table  1000  and the routing table  1001 , and extracts one of the node IDs designated by the closest node ID  10011 . The routing table  1001  holds a plurality of the closest node IDs for one final destination node ID  10010 . For example, the routing table  1001  extracts, as the closest node, the node IDs designed so that the electric wave reception intensity  10001  within the link table  1000  exemplified in  FIG. 4  is higher than a predetermined reference, and the bidirectional link  10002  is established. 
         [0111]    In processing  61  of grouping the final destination node ID for each of the extracted closest node IDs, the high-level relay  10  groups the final destination node IDs corresponding to the closest node ID extracted in the above technique into the same group. In storage processing  62 , the high-level relay  10  stores the information grouped in the above procedure into the alternate relay management table  1002 . For example, the extracted closest node IDs are registered into the alternate relay node IDs of the alternate relay management table  1002 , and the corresponding final destination node IDs are registered in the affiliation node IDs of the alternate relay management table  1002 . Also, the high-level relay  10  assigns the alternate relay group ID to each of the groups, and registers the group IDs in the alternate relay management table  1002 . The above-mentioned processing is repeated, and the plurality of closest nodes are set as the alternate relay nodes to construct the plurality of alternate relay groups. 
         [0112]    The alternate relay node ID  10021  that conducts grouping in the above technique conducts the meter reading information collection of the alternate relay node ID  10021  per se and the affiliation node IDs  10022 ,  10023  in place of the high-level relay  10 . 
       (Meter Reading Information Collection Processing) 
       [0113]    A sequence of the meter reading information collection of the high-level relay  10  and the ad hoc wireless nodes  20 ,  23 ,  24 , and  25  is exemplified in  FIG. 8 , and will be described together with data formats of  FIGS. 9 ,  10 .  11 ,  12 , and  13 . 
         [0114]    The high-level relay  10  that selects the alternate relays in the above technique transmits an alternate relay request  70  to the ad hoc wireless node selected as the alternate relay. The ad hoc wireless node  20  that receives the alternate relay request  70  returns an alternate relay response  71  to the high-level relay  10 . 
         [0115]    As exemplified in  FIG. 9A , the alternate relay request includes a closest destination node ID  700 , a final destination node ID  702 , an alternate relay request code  704 , a number of affiliation nodes  706 , an alternate relay group ID 705 , and affiliation node IDn (n=1, 2, . . . ). Also, the alternate relay request  70  further includes a closest source node ID  701 , and a source node ID  703 . In an example of  FIG. 9 , the node IDs of the ad hoc wireless node  20  selected as the alternate relay are held in the closest destination node ID  700  of the alternate relay request  70 . The node ID of the high-level relay  10  which is a closest source is held in the closest source node ID  701 . The node ID of the ad hoc wireless node  20  selected as the alternate relay is held in the final destination node ID  702 . The node ID of the high-level relay  10  which is the source is held in the source node ID  703 . A predetermined integer value expressed as the alternate relay request is held in the alternate relay request code  704 . A unique integer value specifying the group including the selected alternate relay is held in the alternate relay group ID  705 . The number of ad hoc wireless nodes (the number of nodes belonging to the group) that the ad hoc wireless node  20  selected as the alternate relay conducts the meter reading information collection by deputy is held in the number of affiliation nodes  706 . The node IDs of the ad hoc wireless nodes  20 ,  23 ,  24 , and  25  that the ad hoc wireless node  20  selected as the alternate relay conducts the meter reading information collection by deputy are held in an affiliation node ID  707  as the respective information. 
         [0116]    The affiliation node ID  707  holds all  708  of the ad hoc wireless nodes belonging to the group. The closest destination node ID  700  and the final destination node ID  702  enter the same value, and take, for example, a value of the alternate relay node ID  10021  in  FIG. 6 . The closest source node ID  701  and the source node ID  703  enter the same value, and take, in this case, a value of the node ID of the high-level relay  10 . The alternate relay group ID  705  takes, for example, a value of the alternate relay group ID  10020  in  FIG. 6 . 
         [0117]    On the other hand, in an example of  FIG. 9B , the node ID of the high-level relay  10  is held in a closest node ID  710  of the alternate relay response  71 . The node ID of the ad hoc wireless node  20  which is the closest source is held in a closest source node ID  711 . The node ID of the high-level relay  10  is held in a final destination node ID  712 . The node ID of the ad hoc wireless node  20  which is the source is held in a source node ID  713 . A predetermined integer value expressed as the alternate relay response is held in an alternate relay response code  714 . A predetermined integer value specifying an affirmative response is held in response contents  715 . A unique integer value specifying the group of the alternate relay is held in an alternate relay group ID  716  as the respective information. 
         [0118]    The closest destination node ID  710  and the final destination node ID  712  enter the same value, and in this case take the node ID of the high-level relay  10  as a value. The closest source node ID  701  and the source node ID  703  enter the same value, and correspond to, for example, a value of the alternate relay node ID  10021  in  FIG. 6 . The alternate relay group ID  716  corresponds to, for example, a value of the alternate relay group ID  10020  of  FIG. 6 . 
         [0119]    The ad hoc wireless node  20  that acquires the information of the ad hoc wireless nodes  23 ,  24 , and  25  which conduct the meter reading information collection by deputy by the alternate relay request  70  and the alternate relay response  71  transmit a group ID notification  72  to the ad hoc wireless nodes  23 ,  24 , and  25  which are the affiliation nodes, as illustrated in  FIG. 8 . 
         [0120]      FIG. 10  illustrates an example of the group ID notification  72 . In an example of  FIG. 10 , in a closest node ID  720  of the group ID notification  72 , the routing table  1001  exemplified in  FIG. 5  of the ad hoc wireless node  20  selected as the alternate relay is searched, and the ID of one closest node selected from the closest nodes with the ad hoc wireless nodes  23 ,  24 , and  25  as the final destination node is held. In a closest source node ID  721 , the node ID of the ad hoc wireless node  20  selected as the alternate relay which is the closest source is held. In a final destination node ID  722 , the node IDs of the ad hoc wireless nodes  23 ,  24 , and  25  are held. In a source node ID  723 , the node ID of the ad hoc wireless node  20  selected as the alternate relay is held. In a group ID notification code  724 , a predetermined integer value expressed as the group ID notification is held. In an alternate relay group ID  725 , a unique integer value that specifies the group of the alternate relay is held, as the respective information. 
         [0121]    The ad hoc wireless nodes  23 ,  24 , and  25  that receive the group ID notification  72  store the source node ID  723  (that is, ID of the alternate relay) and the alternate relay group ID  725  in the alternate relay information management table  1003  respectively therein. 
         [0122]    When a preset meter reading information collection period  74  expires, the ad hoc wireless nodes  23 ,  24 , and  25  transmit meter reading information  73  to the ad hoc wireless node  20  selected as the alternate relay. The meter reading collection period may have a time duration, or a clock time may be determined for each of the ad hoc wireless nodes. The meter reading information is measured by the smart meter function unit  203 . The meter reading information may be measured when transmitting the information to the ad hoc wireless node  20 , or information measured at an appropriate timing may be stored. 
         [0123]      FIG. 11  illustrates an example of the meter reading information  73 . In an example of  FIG. 11 , in a closest node ID  730  of the meter reading information  73 , the routing table  1001  exemplified in  FIG. 5  of the source per se is searched, and the ad hoc wireless node  20  selected as the alternate relay is set as the final destination node, and one closest node selected from the closest node is held. In a closest source node  731 , the node ID of the ad hoc wireless node of the source per se is held. In a closest destination node ID  732 , the node ID of the ad hoc wireless node  20  which is the alternate relay that conducts the meter reading information collection by deputy. In a source node ID  733 , the node ID of the ad hoc wireless node of the source per se is held. In a meter reading information code  734 , a predetermined integer value expressed as the meter reading information collection information is held. In an alternate relay group ID  735 , a unique integer value that specifying the group of the alternate relay is held. In a meter reading value  736 , the meter reading value acquired by the meter reading control unit  2030  shown in the functional block diagram of  FIG. 3  is held as the respective information. The node ID of the ad hoc wireless node  20  which is the alternate relay, and the unique integer value specifying the group of the alternate relay can use information stored in conducting the above group ID notification. 
         [0124]    Thus, the ad hoc wireless node  20  which is the alternate relay receives the meter reading information from the respective ad hoc wireless nodes belonging to the alternate relay group. The ad hoc wireless node  20  that collects the meter reading information in the above procedure by deputy holds the meter reading information of the ad hoc wireless nodes  20 ,  23 ,  24 , and  25  in the meter reading information holding table  1004 . Then, a meter reading completion notification  76  is transmitted to the high-level relay  10 . As an example, the alternate relay receives the meter reading information from all of the affiliation nodes, acquires the meter reading information by the smart meter function block of itself, and then transmits the meter reading completion notification. The high-level relay  10  that receives the meter reading completion notification  76  returns a meter reading completion response  77  to the ad hoc wireless node  20  selected as the alternate relay. 
         [0125]    The ad hoc wireless node  20  selected as the alternate relay returns a meter reading information acquisition response  79  to a meter reading information acquisition request  78  from the high-level relay  10 . The meter reading information acquisition request  78  can be transmitted, for example, so that the high-level relay  10  can sequentially collect the meter reading information from the plurality of alternate relays. Also, the high-level relay  10  may control the timing of the meter reading information acquisition request to transmit to the plurality of alternate relays according to the electric wave environment. Alternatively, the meter reading information acquisition request  78  may be transmitted at an appropriate timing. 
         [0126]    Referring to  FIG. 12 , the meter reading completion notification  76  and the meter reading completion response  77  will be described. 
         [0127]    In a closest destination node ID  760  of the meter reading completion notification  76 , the node ID of the high-level relay  10  is held. In a closest source node ID 761 , the node ID of the ad hoc wireless node  20  which is the closest source is held. In a final destination node ID  762 , the node ID of high-level relay  10  is held. In a source node ID  763 , the node ID of the ad hoc wireless node  20  which is the source is held. In a meter reading completion notification code  764 , a predetermined integer value expressed as the meter reading completion notification is held. In an alternate relay group ID  765 , a unique integer value specifying the group of the alternate relay is held as the respective information. 
         [0128]    Also, in a closest destination node ID  770  of the meter reading completion response  77 , the node ID of the ad hoc wireless node  20  selected as the alternate relay is held. In a closest source node ID 771 , node ID of the high-level relay  10  which is the closest source is held. In a final destination node ID  772 , the node ID of the ad hoc wireless node  20  selected as the alternate relay is held. In a source node ID  773 , the node ID of the high-level relay  10  which is the source is held. In a meter reading completion response code  774 , the predetermined integer value expressed as the meter reading completion response is held. In an alternate relay group ID  755 , a unique integer value specifying the group of the alternate relay is held as the respective information. 
         [0129]    Referring to  FIG. 13 , the meter reading information acquisition request  78  and the meter reading information acquisition response  79  will be described. 
         [0130]    In a closest destination node ID  780  of the meter reading acquisition request  78 , the node ID of the ad hoc wireless node  20  selected as the alternate relay is held. In a closest source node ID 781 , the node ID of the high-level relay  10  which is the closest source is held. In a final destination node ID  782 , the node ID of the ad hoc wireless node  20  selected as the alternate relay is held. In a source node ID  783 , the node ID of the high-level relay  10  which is the source is held. In a meter reading acquisition request code  784 , the predetermined integer value expressed as the meter reading information acquisition request is held. In an alternate relay group ID  785 , a unique integer value specifying the group of the alternate relay is held as the respective information. 
         [0131]    In a closest destination node ID  790  of the meter reading information acquisition response  79 , the node ID of the high-level relay  10  is held. In a closest source node ID 791 , the node ID of the ad hoc wireless node  20  which is the closest source is held. In a final destination node ID  792 , the node ID of the high-level relay  10  is held. In a source node ID  793 , the node ID of the ad hoc wireless node  20  which is the source is held. In a meter reading information acquisition response code  794 , the predetermined integer value expressed as the meter reading information acquisition response is held. In an alternate relay group ID  795 , a unique integer value specifying the group of the alternate relay is held. In a meter reading number  796 , a sum (that is, the number of receptions+1) of the ad hoc wireless node  20  which is the alternate relay of the source per se and the number of receptions of the meter reading information  73  received from the ad hoc wireless nodes  23 ,  24 , and  25  is held. In a meter reading information  797 , the respective meter reading information of the ad hoc wireless nodes  20 ,  23 ,  24 , and  25  is held as the respective information. 
         [0132]    The meter reading information  797  holds all  798  of the ad hoc wireless nodes including the ad hoc wireless node  20  which is the alternate relay. The meter reading information  797  includes a node ID  7970  of the ad hoc wireless nodes that transmit the meter reading value, and a meter reading value  7971 . 
         [0133]    In meter reading information acquisition response  79 , as disclosed in  FIG. 13B , the meter reading information  797  holds all of the ad hoc wireless nodes including the ad hoc wireless nodes  20  which is the alternate relays ( 798 ), and packs the meter reading information from the ad hoc wireless nodes into one message, and transmits the message. 
       (Multi-Cast Processing) 
       [0134]    Referring to  FIGS. 21 and 22 , the transfer sequence of a multicast message and a multicast message format will be described. 
         [0135]    The high-level relay  10  and the ad hoc wireless nodes  20 ,  21 ,  22 , and  23  share the determination of the group ID by the communication of the above alternate relay request  70 , the alternate relay response  71 , and the group ID notification  72 . In this example, the ad hoc wireless nodes  20 ,  21 , and  22  are the alternate relays, and the ad hoc wireless node  23  is a node belonging to the same group as that of the ad hoc wireless node  20 . 
         [0136]    In this embodiment, the alternate relay group ID is assigned to the multicast message, and transferred into the alternate relay group. If the alternate relay group ID included in the received multicast message is different from the alternate relay group ID to which the subject device belongs, the alternate relay group ID is discarded without being transferred. As a result, in the ad hoc wireless network, the multicast message can be efficiently transmitted with the use of the alternate relay group ID. 
         [0137]    The high-level relay  10  and the respective ad hoc wireless nodes transmit the multicast messages according to the format of a multicast message  94  illustrated in  FIG. 22 . In the multicast message  94 , in a closest destination node ID  940 , the address information indicating the multicast is held. In a closest source node ID  941 , the high-level relay  10  which is the closest source, or the node ID of the ad hoc wireless node is held. In a final destination node ID  942 , the address information representing the multicast is held. In a source node ID  943 , the node ID of the high-level relay  10  which is the source is held. In a multicast code  944 , a predetermined integer value expressed as the multicast is held. In a group ID  945 , the group ID that is a target of the multicast is held. In a hop limit  946 , the largest number of hops that transmits the multicast is held. In a payload  947 , data per se to be delivered by the multicast is held as the respective information. Data to be delivered by the multicast may be multicast data received from other servers or devices, or may be control information of the ad hoc network. The ad hoc wireless node that receives the multicast message  94  subtracts the hop limit  946  at the time of transfer by one. If the hop limit is  0 , transfer is no more executed. 
         [0138]    In an example of  FIG. 21 , the ad hoc wireless node  20  and the ad hoc wireless node  23  belong to the same alternate relay group, and the ad hoc wireless node  21  and the ad hoc wireless node  22  belong to the different alternate relay groups. 
         [0139]    The ad hoc wireless node  20  that receives the multicast message  95  illustrated in  FIG. 23  from the high-level relay  10  subtracts the hop limit by one, and transmits the message as a multicast message  96  illustrated in  FIG. 24 . On other hand, the ad hoc wireless nodes  20  and  23  may receive a multicast message  97  or a multicast message  98  by the electric wave state. In the ad hoc wireless nodes  20  and  23 , the group ID notified by the alternate relay request or the group ID notification is different from the alternate relay group ID within the message, and therefore the messages are discarded without being transferred. 
         [0140]    The ad hoc wireless node  23  that receives the multicast message  96  illustrated in  FIG. 24  subtracts a hop limit  966  by one, and transfers the message. 
         [0141]    The ad hoc wireless node  21  that receives the multicast message  97  illustrated in  FIG. 25  from the high-level relay  10  subtracts a hop limit  976  by one, and transfers the message. Even when the ad hoc wireless nodes  20 ,  22 , and  23  other than the ad hoc wireless node  21  receive the multicast message  97 , the alternate relay group ID is different from each other, the multicast message  97  is discarded. 
         [0142]    The ad hoc wireless node  22  that receives the multicast message  98  illustrated in  FIG. 26  from the high-level relay  10  subtracts a hop limit  986  by one, and transfers the message. Even when the ad hoc wireless nodes  20 ,  21 , and  23  other than the ad hoc wireless node  22  receive the multicast message  98 , because the alternate relay group ID is different from each other, the multicast message  98  is discarded. 
       CONFIGURATION 
     CONFIGURATION EXAMPLE 1 
       [0143]    The mesh ad hoc network is configured by, for example, a mesh ad hoc network including a plurality of high-level relays and a plurality of ad hoc wireless nodes each having a smart meter function unit, 
         [0144]    in a communication system where the high-level relays and the ad hoc wireless nodes each having the smart meter function unit each have a function of conducting a wireless communication, 
         [0145]    a link table and a routing table are configured by mutual communications of an annunciation message, and 
         [0146]    a multihop communication is conducted with reference to the link table and the routing table, in which 
         [0147]    each of the high-level relays has a function unit of collecting meter reading information of the ad hoc wireless nodes each having the smart meter function unit by the ad hoc wireless nodes each having the smart meter function unit through the mesh ad hoc network, and 
         [0148]    each of the high-level relays has a function of delegating a meter reading information collection of the ad hoc wireless nodes each having the smart meter function unit to the ad hoc wireless nodes each having the smart meter function unit of one hop from the high-level relay through the mesh ad hoc network. 
       CONFIGURATION EXAMPLE 2 
       [0149]    In the mesh ad hoc network according to the configuration example 1, 
         [0150]    each of the high-level relays has a unit of searching a link table and a routing table which are held inside of the high-level relay, and determining the ad hoc wireless nodes each having the smart meter function unit of one hop from the high-level relay that relegates the delegation of the meter reading information collection, when delegating the meter reading information collection to the ad hoc wireless nodes each having the smart meter function unit of one hop from the high-level relay, and holds the information as internal storage. 
       CONFIGURATION EXAMPLE 3 
       [0151]    In the mesh ad hoc network according to the configuration example 1, 
         [0152]    each of the high-level relays has a unit of searching a link table and a routing table which are held inside of the high-level relay, and determining a list of the ad hoc wireless nodes each having the smart meter function unit of one or more hops from the high-level relay that actually acquires the meter reading information, when delegating the meter reading information collection to the ad hoc wireless nodes each having the smart meter function unit of one hop from the high-level relay, and holds the information as internal storage. 
       CONFIGURATION EXAMPLE 4 
       [0153]    In the mesh ad hoc network according to the configuration example 1, 
         [0154]    each of the high-level relays has a function of delivering the ad hoc wireless nodes each having the smart meter function unit of one hot from the high-level relay that relegates delegation of the meter reading information collection according to the configuration example 2, and 
         [0155]    a list of the ad hoc wireless nodes each having the smart meter function unit of one or more hops from the high-level relay that actually acquires the meter reading information according to the configuration example 3 
         [0156]    to the ad hoc wireless nodes each having the smart meter function unit of one hop from the high-level relay as an alternate relay response. 
       CONFIGURATION EXAMPLE 5 
       [0157]    In the mesh ad hoc network according to the configuration example 1, 
         [0158]    the ad hoc wireless node having the smart meter function unit of one hop from the high-level relay, which receives information on the ad hoc wireless node having the smart meter function unit of one hop from the high-level relay that relegates the delegation of the meter reading information collection according to the configuration example 2, and 
         [0159]    the list of the ad hoc wireless nodes each having the smart meter function unit of one or more hops from the high-level relays that actually acquire the meter reading information according to the configuration example 3 
         [0160]    includes the smart meter function unit having a function of returning a response to the high-level relays as an alternate relay response. 
       CONFIGURATION EXAMPLE 6 
       [0161]    In the mesh ad hoc network according to the configuration example 1, 
         [0162]    the ad hoc wireless node having the smart meter function unit of one hop from the high-level relay, which receives information on the ad hoc wireless node having the smart meter function unit of one hop from the high-level relay that relegates the delegation of the meter reading information collection according to the configuration example 2, and 
         [0163]    the list of the ad hoc wireless nodes each having the smart meter function unit of one or more hops from the high-level relays that actually acquire the meter reading information according to the configuration example 3, 
         [0164]    includes a smart meter function unit 
         [0165]    holding the information as internal storage, and 
         [0166]    having a function of notifying all of the ad hoc wireless nodes on the list of the ad hoc wireless nodes each having the smart meter function unit of one or more hops from the high-level relay that acquires the meter reading information, as a group ID notification. 
       CONFIGURATION EXAMPLE 7 
       [0167]    In the mesh ad hoc network according to the configuration example 1, 
         [0168]    the ad hoc wireless node having the smart meter function unit of one or more hops from the high-level relay that receives the group ID notification according to the configuration example 6 includes a smart meter function unit having a mechanism of transmitting the meter reading information during the meter reading information collection period to the ad hoc wireless node having the smart meter function unit of one hop from the high-level relay which receives the delegation of the meter reading information collection from the high-level relay according to the configuration example 2. 
       CONFIGURATION EXAMPLE 8 
       [0169]    In the mesh ad hoc network according to the configuration example 1, 
         [0170]    the ad hoc wireless node having the smart meter function unit of one hop from the high-level relay which receives the delegation of the meter reading information collection from the high-level relay according to the configuration example 2 
         [0171]    includes a smart meter function unit having a function of receiving the meter reading information from the ad hoc wireless node having the smart meter function unit of one or more hops from the high-level relay that receives the group ID notification according to the configuration example 7. 
       CONFIGURATION EXAMPLE 9 
       [0172]    In the mesh ad hoc network according to the configuration example 1, 
         [0173]    the ad hoc wireless node having the smart meter function unit of one hop from the high-level relay which receives the delegation of the meter reading information collection from the high-level relay that receives the meter reading information according to the configuration example 8 
         [0174]    includes a smart meter function unit having a function of holding the meter reading information in an internal storage. 
       CONFIGURATION EXAMPLE 10 
       [0175]    In the mesh ad hoc network according to the configuration example 1, 
         [0176]    the ad hoc wireless node having the smart meter function unit of one hop from the high-level relay which receives the delegation of the meter reading information collection from the high-level relay that holds the meter reading information in the internal storage according to the configuration example 9 
         [0177]    includes a smart meter function unit having a function of transmitting a meter reading completion notification to the high-level relay. 
       CONFIGURATION EXAMPLE 11 
       [0178]    In the mesh ad hoc network according to the configuration example 1, 
         [0179]    the high-level relay that receives the meter reading completion notification according to the configuration example 10 
         [0180]    includes a function of transmitting a meter reading information completion response to the ad hoc wireless node having the smart meter function unit of one hop from the high-level relay that receives the delegation of the meter reading information collection from the high-level relay. 
       CONFIGURATION EXAMPLE 12 
       [0181]    In the mesh ad hoc network according to the configuration example 1, 
         [0182]    the high-level relay that receives the meter reading completion notification according to the configuration example 10 
         [0183]    includes a function of transmitting a meter reading information acquisition request to the ad hoc wireless node having the smart meter function unit of one hop from the high-level relay that receives the delegation of the meter reading information collection from the high-level relay. 
       CONFIGURATION EXAMPLE 13 
       [0184]    In the mesh ad hoc network according to the configuration example 1, 
         [0185]    the ad hoc wireless node having the smart meter function unit of one hop from the high-level relay that receives the delegation of the meter reading information collection from the high-level relay, which receives the meter reading information acquisition request according to the configuration example 11, 
         [0186]    includes a smart meter function unit having a function of packing the meter reading information held in the internal storage according to the configuration example 9 into one message, and returning the message to the high-level relay as a meter reading information acquisition response. 
       CONFIGURATION EXAMPLE 14 
       [0187]    In the mesh ad hoc network according to the configuration example 1, 
         [0188]    the ad hoc wireless node to which the alternate relay group ID is assigned by the means of the configuration example 5 and the configuration example 6 
         [0189]    subtracts, when receiving the multicast packet of the alternate relay group ID to which the subject ad hoc wireless node belongs, a hop limit from the multicast packet, and transfers the multicast packet, and 
         [0190]    discards the multicast packet when receiving the multicast packet of the alternate relay group ID to which the subject ad hoc wireless node does not belong. 
         [0191]    The present invention is available to, for example, an ad hoc wireless network system.