System for transmitting a data signal in a network, method, mobile transmitting device and network device

A system for transmitting a data signal is provided, comprising a plurality of network devices; a network connecting the plurality of network devices based on at least a first communication carrier, wherein the first communication carrier is a wired communication carrier; a network key generator configured to generate a network key; a mobile transmitting device configured to transmit the network key to at least one of the plurality of network devices on a second communication carrier, wherein the second communication carrier is a wireless carrier, and wherein the network devices are configured to communicate with the other network devices based on a link encryption key based on the network key. A corresponding method, a mobile transmitting device and a network device are provided as well.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefit of the earlier filing date of 11 009 787.0 filed in the European Patent Office on Dec. 12, 2011, the entire content of which application is incorporated herein by reference.

The invention relates to a method for transmitting data in a network, to a corresponding system, to a mobile transmitting device and to a network device.

BACKGROUND

In a home network consumer devices like satellite dishes, door cameras, high definition television sets (HDTV), personal computers (PC) are typically installed fixedly at a location in the home. In order to avoid tapping or data theft it is envisaged to encrypt the network. Therefore, a security network key has to be shared among all devices of the home network.

Today, encrypting of power line communication (PLC) links utilizes PBC (push button configuration). With this method, all PLC modems are equipped with a button (software or hardware). If it is pressed, the modem is prepared to be paired with another modem. If within a given short time limit (for instance two minutes) the button is pressed at a second modem, the second modem will be paired with a first one. If a third modem's button is pressed within the time limit it will also be added to the network, etc. Therefore, usually all modems to be paired are connected to a power strip or to a multiple outlet extension block and the buttons are pressed sequentially within the given time limit. Currently, PLC modems are separate small adapters, easy to disconnect and to carry. However, future home network devices will be established which can no longer easily be connected to a single power strip. To press the button of e.g. a door camera, a satellite dish, several television sets (TV), a digital subscriber line modem (DSL-modem), a personal computer (PC) and home servers etc. in a given short time limit becomes more and more complicated.

It is an object of the invention to provide a method for transmitting data, a system, a mobile transmitting device and a network device for transmitting data that provides a convenient way for the user to create a home network and to add devices to it using encrypted links.

The object is achieved by the subject-matter of the independent claims. Further embodiments are specified in the dependent claims, respectively. Details of the invention will become more apparent from the following description of embodiments in connection with the accompanying drawings, wherein features of the various embodiments may be combined unless they exclude each other.

DETAILED DESCRIPTION

FIG. 1depicts a system100for transmitting a data signal in a network102between a first network device104and a second network device106. The wired network102is based on a first communication carrier that is a wired communication carrier, for instance a power line communication (PLC) carrier, Ethernet, Coaxial line (e.g. MoCA® (Multimedia over coax alliance), twisted pair line or a digital subscriber line (DSL) carrier. The first network device104includes a first transmitter110which is connected by the network102to a receiver112in the second network device106.

The first network device104and the second network device106might be realized as e.g. stationary devices that are difficult to move around due to their dimensions or installation locations, as e.g. HDTV sets, satellite dishes on a roof, personal computers PC, home servers etc. Nevertheless the network devices104,106might also be realized as mobile devices that are easier to carry around as e.g. tablet computers, cellular or mobile phones etc.

It is also possible that the network is based on two or more communication carriers, even wireless communication carriers as e.g. Bluetooth® carriers, Zigbee or WiFi carriers.

In accordance with the used communication carriers, the transmitters104and receivers106include corresponding hardware or software to modulate the data signal on the respective communication carrier or to demodulate it and to use respective communication protocols. The respective different communication carriers might also be referred to as different communication technologies in some embodiments.

Generally, the wired network allows bidirectional communication, so that the first transmitter110might also include receiver functionality and the receiver112might include transmitter functionality. Thus the transmitter110and the receiver112might be referred to as “transceivers”.

In order to ensure privacy on the wired network102, a link encryption between the first network device104and the second network device106might be established.

According to an embodiment of the invention, a mobile transmitting device120includes a storage unit122for storing a network key that is generated beforehand. It is possible, for instance, that the network key is generated within the mobile transmitting device120or by any other, external source, as e.g the first or second network device104,106or a further separate network key generator. The “mobile” transmitting device120should be easily portable by a user from one network device104to another network device106. This might be achieved by corresponding outer dimensions and by an accumulator as a power source. The mobile transmitting device120might be embodied e.g. as a cellular phone, a smartphone, a tablet computer, a personal digital assistant (PDA), as a notebook computer, or as a remote control (RC).

The mobile transmitting device120includes an interface124, e.g. a further transmitter or transceiver, for transmitting the network key to the first network device104and the second network device106via a second communication carrier126, which is different from the first communication carrier102. The second communication carrier126might be implemented e.g. as a near field communication (NFC) carrier or a radio frequency identification (RFID) carrier, or a Bluetooth® carrier.

Near field communication, or NFC, allows for simplified transactions, data exchange, and wireless connections between two devices in proximity to each other, usually by no more than a few centimeters. The Near Field Communication Forum (NFC Forum) formed in 2004 promotes sharing, pairing, and transactions between NFC devices and develops and certifies device compliance with NFC standards. NFC is a set of short-range wireless technologies, typically requiring a distance of 4 cm or less. NFC operates at 13.56 MHz on ISO/IEC 18000-3 air interface and at rates ranging from 106 kbit/s to 424 kbit/s. NFC always involves an initiator and a target; the initiator actively generates an RF field that can power a passive target. This enables NFC targets to take very simple form factors such as tags, stickers, key fobs, or cards that do not require batteries. NFC peer-to-peer communication is possible, provided both devices are powered. There are two modes, a passive communication mode: The initiator device provides a carrier field and the target device answers by modulating the existing field. In this mode, the target device may draw its operating power from the initiator-provided electromagnetic field, thus making the target device a transponder; and an active communication mode: Both initiator and target device communicate by alternately generating their own fields. A device deactivates its RF field while it is waiting for data. In this mode, both devices typically have power supplies.

The interface124of the mobile transmitting device120communicates via the second communication carrier126with corresponding interface127,128(e.g. a further receiver or transceiver) of the first network device104and the second network device106, respectively. The corresponding interfaces127,128transmit the received network key to a respective link encryption generator130,132in the first network device104and the second network device106, respectively.

According to an embodiment, the link encryption key might be equal to the network key, it is however also possible that the link encryption key is adapted to an individual communication carrier that is used on the network102.

The link encryption generator130,132generates a link encryption key based on the network key forwarded via the interfaces127,128and forwards the link encryption key to the transmitter110and the receiver112. Based on the link encryption key the communication via the network102between the first network device104and the second network device106will take place.

The mobile communication device120might also include a transceiver that is connected or connectable to the network102, so that it might be paired with the other devices and use the link encryption key when communicating on the first communication carrier with the other network devices.

A corresponding method is schematically depicted inFIG. 2. In step S200a network key is generated.

In step S202the network key is transmitted from a mobile transmitting device to at least one of a plurality of network devices based on a second communication carrier.

In a step S204a link encryption key is generated based on the network key for the first communication carrier.

In a step S206data is transmitted between network devices in the network based on the link encryption key.

The generation of the network key might also be done in one of the stationary devices and transmitted to the mobile device for exchange to further devices.

InFIG. 3a mobile transmitting device120for transmitting a network key used for communicating based on a first communication carrier is schematically depicted. It includes a storage unit122for storing a network key and a transmitter124configured to transmit the network key based on a second communication carrier to a network device, wherein the second communication carrier is a wireless communication carrier.

InFIG. 4a schematic block diagram of a network device104is depicted. It includes a transmitter110for transmitting a data signal on a network based on a first communication carrier and a link encryption key, an interface127configured to receive a network key based on a second communication carrier, wherein the second communication carrier is a wireless communication carrier, and a link encryption key generator130configured to generate the link encryption key based on the network key.

InFIG. 5a further embodiment of a system according to an embodiment of the invention is depicted. In the depicted system a plurality of consumer devices like e.g. a satellite dish including a receiver, a high definition television (HDTV), a WiFi router, a baby monitor, a personal computer PC, an audio system, and an audio video home server are connected via a power line network. A smartphone is depicted as a mobile transmitting device which uses a near field communication (NFC) carrier or a radio frequency identification (RFID) carrier for carrying a network encryption network key to the multiple devices in a meshed home network. In the home network multiple devices communicate with each other in the meshed network. Broadcast messages to all devices or multicast messages to some devices are possible.

It is also possible that the multiple devices in the home network communicate over other carriers as e.g. an Ethernet network, over coaxial cables, or other network protocols like e.g. HomePNA (twisted pair cables), WiFi, Bluetooth, ZigBee, etc. Many or all of the devices are equipped with an NFC interface. A portable NFC device like a smartphone, tablet or remote controller RC for a television TV can be used to share an encryption network key among all devices. The portable NFC device might also be referred to as mobile transmitting device.

If two devices equipped within an NFC interface are brought to a very close distance (e.g. 5 cm) an NFC transmission between those devices is activated (“touching”). Hence, the network key can be transmitted to a first device, when the mobile transmitting device is in close contact to the first device, and to a second device of the home network, when the mobile transmitting device is in close contact to the second device. With this method, it is possible that the user carries the mobile transmitting device from one device of the home network to the next device, transmitting the network key to the respective devices one after the other, until all devices of the home network received the network key. It might be possible of course that two devices of the home network can receive the network key at the same time, e.g. if the two devices are located closely together.

When a portable NFC device being able to generate and to carry the encryption network key touches a first stationary networked device a network key might be generated, forwarded to the stationary networked device and stored on the portable NFC device. This stationary device shall use this network key to generate a link encryption key used for communication on the networks that it is connected to. It is, however, possible that the link encryption key is equal to the network key, e.g. if the portable NFC device is able to generate a link encryption key for the communication among the stationary devices of the home network. A device might be connected e.g. to power line communication PLC as well as to a WiFi network. If the portable NFC device touches another network device the network key shall be transferred to this device for future link encryptions on his networks.

If two portable NFC devices touch each other it may be arbitrated who will carry the network key to the other devices. Alternatively both devices can be used for a future device adding to the network.

The portable device might provide a selection possibility to the user if the network key to be used shall be generated new, taken from the stationary device or taken from the network key storage. If the user wishes to setup a new network the initial network key has to be generated. To add further devices to the network this network key has to be stored and used when additional devices are added.

If there is already an encrypted network and a new portable device is added, the network key from the stationary device shall be used for the communications to the new device.

FIG. 6shows schematically the further embodiment of a system according to the invention.

As it is depicted inFIG. 6, the mobile or portable transmitting device120transmits the network key via the NFC interface602to a first stationary device 1620, a second stationary device 2622and a further stationary device N624, which are equipped with corresponding NFC interfaces604,606,608. Each of the stationary devices includes a link encryption key generator610,612,614, respectively, which generates from the received network key corresponding link encryption keys for their particular communication carriers in accordance with the respective communication protocols that are used by those stationary devices604,606,608. For instance, the stationary device604generates respective link encryption keys for power line communication PLC and for WiFi communication. The second stationary device generates link encryption keys for power line communication and for Ethernet (ETH).

Every network might use its network specific link encryption key. This network specific link encryption key is generated based on the network key received via NFC and should be reproducible when a new device is added to the network later.

If not all devices are supported with an NFC interface, a mix of NFC, PPC or UCPK technologies might be used. UCPK (user configured pathway/network key) allows entering a network key to a wizard-type application. In this embodiment the touching of an NFC device is an equivalent action to pressing the button. If the NFC interface is touched and an encryption network key is shared between the NFC enable device, this network key shall be used for future press button control. This node shall send an (PEB) Push-Button_Event notification message. Then, or if within a given time period this device receives a PB_Event notification message, the network type specific PBC protocol is started. The network key initially exchanged should be used for the encryption of the network.

The power line communication (PLC) network might be a multiple-input multiple-output (MIMO) PLC network.

With the embodiments of the invention an encryption network key can be transported in wired home networks to the network devices via an NFC device and it is possible to combine the encryption of multiple networks (multiple physical layers) using NFC.