WO2011139138A1

WO2011139138A1 - Method of providing multi address binding in a network

Info

Publication number: WO2011139138A1
Application number: PCT/MY2011/000035
Authority: WO
Inventors: Khoshdelniat Reza; Rao Sinniah Gopinath; Suryady Zeldi; Sarwar Usman
Original assignee: Mimos Berhad
Priority date: 2010-05-06
Filing date: 2011-04-19
Publication date: 2011-11-10
Also published as: MY159280A

Abstract

Sensor nodes (20) are usually bound to a main gateway (24) in a wireless sensor network (22). The present invention proposes a solution which comprises creating novel socket address for other new gateways and communicators (26) to connect with sensors in a wireless sensor network. Socket addresses for other new gateway or communicators are provided (60). The binding status of new gateway or communicators is bound (68) to establish connection. After receiving gateway advertisement packet from a sink such as gateway or communicator, the sensor node will save the address of the new gateway or communicator and copy the socket address to the main socket address (74). Then, sensor data can be sent to the desired new communicator or gateway (76). After the data is sent, the sensor will copy back the socket address of the main gateway in the main socket address (78).

Description

METHOD OF PROVIDING MULT I ADDRESS BINDING IN A NETWORK

The present invention relates generally to a wireless node of network communications, more particularly to address binding of a wireless node in a network.

BACKGROUND

Wireless sensor network is a useful network for monitoring data. A plurality of sensor nodes is assigned in multiple places where sensors are located. Sensor nodes in a wireless sensor network can be connected in a network with a gateway. The gateway is connected to the sensor node through a gateway discovery process. The sensor node will first create a socket for data flow and choose a specific communication protocol. Then, the node will create a suitable socket address, which includes protocol and port number to be used for data transfer and the address structure of the destination.

The sensor node will bind the created socket to socket address port number and the destination address structure. After binding the socket, the node will send a gateway discovery packet and after receiving a gateway advertisement packet or a reply for this gateway discovery packet, it will set that gateway as its main gateway and will get bound to that gateway. The sensor node provides sensor data through the main gateway. After the sensor node is bound to the main gateway, other gateway or communicator can't communicate with the sensor node. There are several disadvantages if the sensor node socket gets bound to the main gateway. If a communicator, such as a Personal Digital Assistant or other mobile device, request sensor data from the sensor node, the direct connection can't be established. Hence, the communicator needs to request data through main gateway and it can cause some limitation to the communicator.

Till now there is no method of binding a sensor network with multiple gateways or communicator. It is an object of the invention to provide multiple binding in a wireless sensor network so that multiple gateway or communicators can communicate directly with the sensor node. Direct communication with the sensor node will reduce communication load in the main gateway. SUMMARY OF INVENTION

The present invention proposes a solution which comprises creating novel socket address for gateways and communicators in a wireless sensor network. After receiving gateway advertisement packet from a sink such as gateway or communicator, the sensor node will save the address of the gateway or communicator and copy the socket address to the main socket address. Then, the data is sent to the desired communicator or gateway. After the data is sent, the sensor will copy back the socket address of the main gateway in the main socket address.

Some wireless sensor network has security protocol. Security issues are not a part of this invention. During authentication, the sensor nodes and gateway will verify each other so that no node is compromised by hacker.

The invention presents a method to enable sensor nodes in a network to get bound to more than one gateway or communicator. The method also enables the nodes to receive request packet from more than one gateway or communicator and reply to them without interfering with their periodical data sent to the gateway.

Multi-address binding is described to enable sensor nodes to be bound with more than one gateway. Multi-address binding in sensor nodes allow sensor node in the coverage of more than one gateway to be enabled. More than one communicator can also directly communicate with the sensor node.

The sensor node has the ability to get bound to gateways and communicators at the same time. The sensor node will usually send data periodically to the gateway. If a communicator request for data, the sensor node can reply to the communicator without interfering with its periodical data sent to the gateway.

Clients accessing sensor network from the internet would be able to send their request to the nodes through different gateways and receive the reply from different gateways. This would enable efficient traffic management in the sensor network. BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described in greater detail, by way of an example, with reference to the accompanying drawings, in which:

Fig. 1 shows an overview of wireless sensor network according to the invention;

Fig. 2 shows a flow chart of address binding according to prior art; and Fig. 3 shows a flow chart of address binding according to the invention.

DESCRIPTION OF EMBODIMENTS

Sensor nodes 20 in a wireless sensor network 22 perform gateway discovery process to get bound to a gateway 24. Sensor nodes could only bind to one gateway 24 with known methods. In such sensor network, communicators 26 such as mobile device can only communicate with the gateway and not the sensor nodes directly.

As shown in Fig. 1 , an overview of proposed wireless sensor network 22 showing a gateway 24 connecting sensor nodes 20 and communicators 26. Sensor nodes are connected to a gateway to be connected to internet 28. IPv6/IPv4 clients 30 are connected through wired, WiFi or WiMAX connection to internet and gateway. Communicators 26 are directly connected to sensor nodes 20. It is an object of the invention to enable communicators 26 or gateways 24 to connect directly to sensor node 20 even if the sensor node 20 is already bound to a gateway 24.

Prior to explaining the method involved in this invention, the method used in prior art will first be described for comparison purpose, as shown in Fig. 2. Sensor node will first create a socket 32 and will choose a transport protocol for message flow. Then, it will create a socket address 34 which includes address destination, address type and port number. The address of the destination is the address of the gateway or communicator. The address type is used as address type of sensor nodes and gateways or communicators in wireless sensor network. The port number is for the socket address to be used. After creating the socket address, the sensor node will bind the socket created for the specific message transport protocol, with the port number and destination address defined in socket address. So any message or any data read from the sensors will be sent through the socket to the address defined in socket address which is gateway address.

The sensor node will also define variables to check its binding with the gateway. It will assign a numeric value for gateway associate state packet, which if the state is equal to 1 it means that the sensor node is bound to gateway. The gateway associate state is set to 0 36.

After creating socket address, the sensor node will perform gateway discovery which is done by broadcasting a gateway discovery packet 38. The sensor node and the gateway should be working in the same frequency channel in order to communicate with each other. The sensor nodes wait for an interval to receive message 40.

At the same time, the gateway will be broadcasting periodical gateway advertisement packets. When the gateway receives a gateway discovery message from the sensor nodes, it will reply it back with a gateway advertisement packet which includes message type which is a router advertising type and the gateway source address. When the sensor node receives a message 42, particularly gateway advertisement packet 44, it will check if it is bound to the gateway.

The checking is performed by checking the numeric value of gateway associate state 46. If it is set to 1 , then it means the sensor node already has a gateway bound and then it will discard the gateway advertisement packet 48. If the gateway associate state is equal to 0 then it means that the sensor node still doesn't have any gateway bound. So it will save the source address of gateway advertisement packet to send its messages to the gateway with that type of address 50. Then, the sensor node will set the gateway associate state to 1, which means it is bound to a gateway so that it would discard other gateway advertisement packet 52. After binding to a gateway, the sensor node depending on the application will periodically 54 read data from the sensors and send the data to the gateway 56. From time to time, the connection with gateway is checked if it is lost 58. If the connection is lost, the gateway associate state packet is reset to 0. If another gateway or communicator comes into the network and tries to communicate with the sensor node, the messages from the gateway or communicator will be discarded 48. When the gateway communicator sends a gateway advertisement packet, the node will check the gateway associate state value. If the value is set to 1 , it means the sensor node is bound to a gateway. The sensor node will discard the gateway advertisement packet sent by other gateway or communicator. This issue makes the sensor node limited to only one gateway and the sensor node will not be able to communicate with any other gateway or communicator.

In order to solve this problem and enable the sensor nodes to be bound to multiple gateway or communicator, a method is proposed to enable the sensor nodes to be bound to multiple gateways and communicators by creating new socket addresses and doing gateway discoveries.

By enabling multi address binding in sensor nodes, the sensor nodes 20 will be able to communicate with multiple gateways 24 and also communicators 26. In this case, when a communicator 26 wants to receive the data from the sensors, it can directly request it from the sensor node 20 and it is not necessary to get connected to the gateway 24 and request the data from the gateway. Requesting the data from the gateway 24 might not result in immediate response. In the sensor network 22, there is large number of sensor nodes 20, and also due to MAC protocols and routing used in the wireless sensor networks 22, a delay is present in response time and the communicator 26 might not get an immediate response. But with multiple address binding, the sensor nodes 20 can be connected to multiple communicators 26 and also gateways 24. The communicators 26 can receive instant response upon requesting data from the sensor nodes 20.

The proposed invention, as shown in Fig. 3, starts with the sensor node creating a socket for data flow 32. The sensor node creates a socket and chooses a transport protocol for message flow. Then, it will create a socket address for the main gateway which includes address of destination, address type and port number 34. The address of destination is the address of the main gateway. The address type is used as address type of sensor nodes and gateways or communicators in wireless sensor network. The port number is the socket address to be used. The sensor node will also create a socket address to keep the address and address type of the main gateway. After creating the socket address, the sensor node will bind the socket created for the specific message transport protocol, with the port number and destination address defined in the socket address 37. So any message or any data read from the sensors will be sent through the socket to the address defined in the socket address which is the main gateways address.

The sensor will create other socket address for the other gateway and communicators in the network 60. The number of socket address created depends on the application and the gateways and communicators that the node will be communicating with. The number of socket address for other gateway or communicators can be determined to allow the number of other gateway or communicator to communicate with sensor node. For each socket address created for a gateway or communicator, there should be a numeric variable to check whether the socket address is bound to any gateway or communicator. The variable for the socket address would be gateway or communicator associate state. If any of these variables is 0, it means that no gateway or communicator has been assigned for that socket address created. The associate state for other created communicators and gateway socket is set as unbound 62. After creating a socket address, the sensor node would perform a gateway discovery which is done by broadcasting a gateway discovery message 39. The sensor node and the gateway should be working in the same frequency channel in order to communicate with each other. At the same time, the gateway will be broadcasting periodical gateway advertisement messages. When the gateway receives a gateway discovery packet from the sensor node, it will reply with a gateway advertisement packet which includes the message type which is a router advertising type and the gateway source address. The sensor node waits for an interval 40 to receive message 42. When the sensor node receives the gateway advertisement packet 44, it will check whether it is bound to a main gateway 46. This checking is performed by checking the value of main gateway associate state. If it is set to 1 , then the sensor node is already bound to a main gateway 64. It will discard the main advertisement packet 48. If the main gateway associate state is 0 then it means that the sensor node is not bound to any main gateway. It will save the source address of the gateway advertisement packet which is the address of the gateway in its socket address as the address of its main gateway 50. It will also save the address type of the gateway advertisement packet to send its messages to the main gateway with that type of address. Then, the sensor node will set the main gateway associate state to 1, which means the main gateway is bound 52. After binding to the gateway, the sensor node depending on the application will periodically 54 read the sensors and send the data to gateway 56.

The sensor node will periodically send gateway discovery message to discover new gateways or communicators. Communicators and gateways periodically send gateway advertisement packet. When a sensor node receives a gateway advertisement packet, it will check its socket address binding status. If the main gateway associate state is 1 , the new main gateway address and address type is save in a socket address 66. Then, the socket address of new gateway is set as bound 68. The same procedure is used for discovering a communicator.

When the gateway or communicator requests data from sensor, upon receiving the request packet 70, the sensor will check the source address of the request message. If the source address is from any of the gateways or communicators which it had address saved 72, which indicates that it has been bound, it will reply back to that gateway or communicator. In order to send the reply message, the sensor node will copy the address and address type of that new gateway or communicator from its socket address to the socket address of the main gateway 74. The sensor node will then read the sensor data and send it through the main gateway socket address 76 to new gateway or communicator. After sending data to the gateway, the sensor node will replace back the address and address type of the main gateway back to its socket address.

The address and address type of communicator or gateway is copied to the socket address of the main gateway 78. The socket created is bound to main gateway address and would only send data to address in main gateway socket address. When the sensor wants to send data to any communicator or gateway, it must first copy the address and address type of communicator into the socket address of the main gateway. In this method, the request messages arriving will not interfere with periodical data sent to the main gateway. The sensor node will remain sending the sensor data periodically to the main gateway. Any number of data request arrive from the communicators will not be interfered. Accordingly, the invention disclosed a method for address binding in a sensor node. It is the combination of the above features and its technical advantages give rise to the uniqueness of such invention. Although the descriptions above contain much specificity, these should not be construed as limiting the scope of the embodiment but as merely providing illustrations of some of the presently preferred embodiments.

Claims

1. A method of providing multi address binding in a network, comprising:

providing a socket address for a main gateway (34);

setting the socket address binding status of main gateway as bound (36); providing socket addresses for other gateway or communicators (60);

setting the socket address binding status of other gateway or communicator as unbound (62);

providing gateway discovery packet (39);

responding to unbounded gateway advertisement packet by saving the address of the new gateway or communicator in the socket address (66); and setting the socket address of new gateway or communicator as bound (68); wherein saving the address of new gateway or communicator in socket address (66) and binding the new gateway or communicator socket address (68) allows the new gateway or communicator to initiate connection with sensor node.

2. A method according to claim 1 , further comprising:

responding to request packet from bounded source address by copying address of new gateway or communicator to main gateway socket (74);

reading sensor data and sending data through main gateway socket address (76) to new gateway or communicator; and

copying the address of main gateway to main gateway socket address (78).

3. A method according to claim 1 , wherein the socket address comprises destination address, address type and port number.

4. A method according to claim 1 , wherein the number of socket address for other gateway or communicators be determined to allow the number of other gateway or communicator to communicate with sensor node.

5. A wireless sensor network (22), comprising:

a main gateway (24) at a first site;

a sensor node (20) as claimed in any of the preceding claim at a second site; and

a gateway or communicator (26) at a third site;

signals at the first site being connected to the second site and signals at the second site being connected to the third site.