Patent Description:
A network identification code is needed when multiple networks are operating on same spectrum at the same geographical area. The network identification code may be used to separate transmissions from different networks from each other. The network identification code needs to be long enough, i.e. number of bits, to provide at least local uniqueness of the network that is transmitted every packet transmission. For example, the length of the network identification code may be <NUM>, <NUM> or <NUM> bits. Such bit sequence for network identification code at each packet transmission is quite considerable amount of overhead especially when data transmissions are sufficiently small, which may be the case e.g. in Internet of Things (IoT) operation. For example, if data amount transmitted by an IoT device as a single data burst is <NUM> bytes, resulting that if the network identification code with length of <NUM> to <NUM> bits is used in each of the packet transmission, the introduced overhead is between <NUM> to <NUM> percent.

In Wireless Local Area networks (WLAN) and Bluetooth Low Energy (BLE) networks the network identification code may be added into each packet. BLE uses <NUM> bits long address in a header of the packet after general synchronization field. In BLE the network identification code is called as access address, even though it may be also used for forming BLE mesh networks. In WLAN each packet comprises a Basic service set (BSS) ID that is <NUM> bit address field which is Medium access (MAC) address of an access point (AP), so that this BSS ID identifies that certain transmission is part of this BSS. Additionally, in WLAN Service set identifier (SSID) may be used, which is transmitted in a beacon message that is the same for all BSS parts of the network. Thus, each packet transmission in WLAN comprises BSS ID (<NUM> bits) receiver MAC address (<NUM> bits) and transmitter MAC address (48bit). Thus, the WLAN solution is very brute force. Cellular systems relay on the fact that each network operates at separate licensed frequency or when operating at unlicensed the assumption is that there are no overlapping frequencies between networks.

Therefore, there is a need to develop further solutions to separate transmissions from different networks from each other, especially when they are operating in overlapping spectrum.

A patent application <CIT> discloses a method for generating a control data unit a physical layer (PHY) preamble of the control data unit. In generating the PHY preamble an address field is generated to indicate a communication device for which the data unit is intended, and a frame type field is generated to indicate a type of the control data unit.

A publication "<NPL> discloses technical studies focused on the MAC and higher layers of DECT-<NUM> New Radio Interface (NR).

A publication <NPL>, discusses the network and device identities in DECT-<NUM> system.

An objective of the invention is to present communication apparatuses, methods, a system, and a computer program. Another objective of the invention is that the apparatuses, the methods, the system, and the computer program enables a simple way to separate transmissions from different networks from each other, especially when they are operating in overlapping spectrum.

The objectives of the invention are reached by methods, apparatuses, a system and a computer program as defined by the respective independent claims.

According to a first aspect, a communication apparatus is provided, wherein the communication apparatus comprises: a processor part, and a data transfer part, wherein the apparatus is configured to: receive, by the data transfer part, a packet comprising a network identification code (NIC) of a communication apparatus that transmitted the packet, wherein a header field of the packet comprises a first part of the NIC and a second part of the NIC is included in another field of the packet; and define, by the processor part, that the received packet is from a network to which the communication apparatus belongs, if the first part of the NIC of the received packet corresponds to the first part of the NIC of said communication apparatus, wherein the apparatus is further configured to: perform an error check to ensure whether the reception of the data field of the received packet, was correct or not, in response to the definition that the received packet is from the network to which the communication apparatus belongs, wherein the reception of the packet is incorrect, if the second part of the NIC of the received packet does not correspond to the second part of the NIC of said communication apparatus.

The header field of the packet may further comprise identification information representing the transmitting communication apparatus and/or identification information representing the receiving communication apparatus.

Furthermore, the communication apparatus may be configured to perform a further confirmation that the received packet is from the network to which the communication apparatus belongs based on the identification information representing the transmitting communication apparatus and/or the identification information representing the receiving communication apparatus.

Alternatively or in addition, the second part of the NIC may be included in an error detection code of a data field of the packet.

The error detection code may be Cyclic Redundant Check (CRC), and in response to definition that the received packet is from the network to which the communication apparatus belongs, the communication apparatus may further be configured to: perform a XOR operation for the second part of the NIC with one of the following: the CRC defined for the data field of the received packet or the CRC included in the data field of the received packet; compare the result of the XOR operation to the other one of the following: the CRC defined for the data field of the received packet or the CRC included in the data field of the received packet; and define that the reception of the packet was correct, if the result of the XOR operation corresponds with the CRC to which it is compared.

The communication apparatus may further be configured to: determine a message indicating a correct reception of the packet to be transmitted to the communication apparatus from which the packet is received, in response to the detection of a correct reception; or determine a message indicating an incorrect reception of the packet to be transmitted to the communication apparatus from which the packet is received, in response to the detection of an incorrect reception.

Alternatively or in addition, the communication apparatus may further be configured to: define that the received packet is from another network, if the first part of the NIC of the received packet differs from the first part of the NIC of the communication apparatus, and obtain activity information representing activity of said another network based on at least one packet received from said another network.

Alternatively or in addition, the communication apparatus may be configured to obtain the NIC by configuration, other communication technique, or receiving a broadcast message comprising the NIC.

Alternatively or in addition, the packet may be a physical (PHY) layer packet.

Alternatively or in addition, the NIC may be independent from an actual Network ID of the network, the NIC may be at least partly derived from the actual Network ID of the network, or the NIC may be directly the actual Network ID of the network.

Alternatively or in addition, the network may be a wireless mesh network, a wireless Bluetooth Low Energy (BLE) -based radio network, a wireless local area network (WLAN), Thread network, Zigbee network, Public Land Mobile Network (PLMN), or cellular network.

According to a second aspect, a communication system is provided, wherein the communication system comprises: a plurality of communication apparatuses comprising a first communication apparatus and a second communication apparatus; wherein each communication apparatus of the system is configured to provide a bi-directional radio communication with at least one other communication apparatus of the system; wherein the first communication apparatus is configured to determine a packet to be transmitted to at least the second communication apparatus, the transmitted packet comprises a network identification code (NIC) of the first communication apparatus, wherein a header field of the packet comprises a first part of the NIC and a second part of the NIC is included in another field of the packet; and wherein the second communication apparatus is configured to: receive the packet transmitted by the first communication apparatus, and define that the received packet is from the network to which the second communication apparatus belongs, if the first part of the NIC of the received packet corresponds to the first part of the NIC of the second communication apparatus, wherein the second apparatus is further configured to: perform an error check to ensure whether the reception of the data field of the received packet, was correct or not, in response to the definition that the received packet is from the network to which the second communication apparatus belongs, wherein the reception of the packet is incorrect, if the second part of the NIC of the received packet does not correspond to the second part of the NIC of the second communication apparatus.

According to a third aspect, a method for a communication apparatus as described above is provided, wherein the method comprises steps of: receiving a packet comprising a network identification code (NIC) of a communication apparatus which transmitted the packet, wherein a header field of the packet comprises a first part of the NIC and a second part of the NIC is included in another field of the packet; and defining that the received packet is from a network to which the communication apparatus belongs, if the first part of the NIC of the received packet corresponds to the first part of the NIC of said communication apparatus wherein the method further comprises step of: performing an error check to ensure whether the reception of the data field of the received packet, was correct or not, in response to the defining that the received packet is from the network to which the communication apparatus belongs, wherein the reception of the packet is incorrect, if the second part of the NIC of the received packet does not correspond to the second part of the NIC of said communication apparatus.

According to a fourth aspect, a computer program is provided, wherein the computer program comprises instructions which, when the program is executed by a communication apparatus as described above, cause the communication apparatus to carry out at least the steps of the methods as described above.

According to a fifth aspect, a computer readable medium is provided, wherein the computer readable medium comprises the computer program as described above.

<FIG> illustrates an example environment, wherein the embodiments of the invention may be implemented as will be described. The example environment comprises a first wireless communication network, i.e. system, <NUM> and a second wireless communication network, i.e. system, <NUM>. The first wireless communication network <NUM> comprises a plurality of wireless communication apparatuses <NUM> (illustrated with circles in <FIG>). The second wireless communication network <NUM> comprises a plurality of wireless communication apparatuses <NUM> (illustrated with squares in <FIG>). The first wireless communication network <NUM> and the second communication network <NUM> are operating on the same spectrum at the same geographical area, i.e. within the example environment. Because of the same spectrum use radio transmissions transmitted by the communication apparatuses <NUM> of the first network <NUM> may be received by the communication apparatuses <NUM> of the second network <NUM> and vice versa. In order to separate the transmissions of the first network <NUM> from the transmissions of the second network <NUM>, the communication apparatuses <NUM> of the first network <NUM> are configured to use a network identification code (NIC) representing the first network <NUM> in their transmissions. Furthermore, in order to separate the transmissions of the second network <NUM> from the transmissions of the first network <NUM>, the communication apparatuses <NUM> of the second network <NUM> are configured to use a NIC representing the second network <NUM> in their transmissions. Each communication apparatus <NUM>, 102a, 102b, <NUM> according to the invention is configured to add the NIC according to the invention as will be described into each packet, which the apparatus <NUM>, 102a, 102b, <NUM> transmits.

The solution according to the present invention described in this application may be implemented to any wireless communication network that uses frequent signaling of the NIC. Preferably, the solution according to the present invention may be implemented in wireless communication networks complying DECT-<NUM> standard. Some non-limiting example wireless communication networks to which the solution according to the present invention may be implemented may comprise, but is not limited to, BLE mesh network, Thread network, Zigbee network, Public Land Mobile Network (PLMN), WLAN network, cellular network, or wireless mesh network, e.g. wireless sensor network, and/or any other wireless networks.

Typically, communication apparatuses <NUM>, 102a, 102b, <NUM> of the network <NUM>, <NUM> are capable to receive transmissions with one radio technology, e.g. BLE transmissions or WLAN transmission, which transmission are all from the same network <NUM>, <NUM>. However, according to an example of the invention, one or more communication apparatuses <NUM>, 102a, 102b, <NUM> of the network <NUM>, <NUM> may be capable to receive transmissions with two or more radio technologies, e.g. BLE transmissions and WLAN transmissions, which transmission are all from the same network <NUM>, <NUM>.

DECT-<NUM> is radio access technology developed by ETSI. DECT-<NUM> supports massive machine type communication (mMTC) and ultra-reliable low latency communication (URLLC). On Physical (PHY) layer the key technology components of the DECT-<NUM> are: Orthogonal frequency-division multiplexing (OFDM), adaptive modulation and coding schemes (MCS), Modern Channel coding methods (Turbo, LDPC, Convolutional coding), Hybrid automatic repeat request (HARQ) for both scheduled and contention based transmissions, and support of multi-antenna transmissions with different Multiple-Input and Multiple-Output (MIMO) streams. On Medium access (MAC) layer and from system aspects the key technology components of the DECT-<NUM> are: support of high number of IoT sensors, actuators and other industrial applications; support of Mesh network topology, support of URLLC communication with very short delay (typical application may be wireless microphones); operation on frequencies, that are license exempt; and support of multiple overlapping non-coordinated networks with cognitive radio capabilities to share spectrum resources between multiple networks.

Next an example of a method according to the invention is described by referring to <FIG> schematically illustrates the invention as a flow chart. The example method is described by using two communication apparatuses, i.e. a first communication apparatus 102a and a second communication apparatus 102b, both belonging to the same network <NUM>. However, the network <NUM> according to the invention may comprise a plurality of communication apparatuses <NUM> comprising the first communication apparatus 102a and the second communication apparatus 102b. Each communication apparatus <NUM>, 102a, 102b of the network <NUM> may be configured to provide a bi-directional radio communication with at least one other communication apparatus <NUM> of the system <NUM>. In other words, each communication apparatus <NUM>, 102a, 102b may act as a transmitting apparatus and/or as a receiving apparatus. However, in the example method the first communication apparatus 102a is acting as the transmitting apparatus and the second communication apparatus 102b is acting as the receiving apparatus. Each communication apparatus <NUM>, 102a, 102b of the network <NUM> is capable to transmit and receive one or more packets. Preferably, the transmitting apparatus and the receiving apparatus may be identical with each other. However, the invention is not limited to that.

At a step <NUM>, the first communication apparatus 102a determines a packet <NUM> to be transmitted to at least the second communication apparatus 102b. The first communication apparatus 102a further transmits the determined packet <NUM>. The transmission of the packet <NUM> may be e.g. a broadcast transmission or a unicast transmission. The broadcast transmission may be destinated to all the apparatuses <NUM>, 102b of the network <NUM> or to a group of apparatuses <NUM>, 102b of the network <NUM>, i.e. multicast transmission. The unicast transmission may be destinated to a single apparatus <NUM>, 102b of the network <NUM>.

<FIG> illustrates schematically an example format of the packet <NUM> according to the invention. However, the invention is not limited to that and any other packet format may be used. The packet <NUM> may be, but is not limited to, a PHY layer packet <NUM> as illustrated in the example of <FIG>. The example packet format of <FIG> comprises the following fields: Synchronization Training Field Symbols (STFS) <NUM>, channel training field (CTF) <NUM>, PHY header field, i.e. PHY control field, <NUM>, and data field <NUM>. The STFS field <NUM> is used to provide time and frequency synchronization for the receiving apparatus. Additionally, the STFS field <NUM> may be used to other purposes, such as adjusting gain of the receiving apparatus. The CTF field <NUM> is used for channel estimation purposes in the receiving apparatus. The PHY header field <NUM> is used to transmit necessary information how the data field is transmitted. The PHY header field <NUM> may comprise, but is not limited to, information used Modulation and coding scheme (MCS), a receiver address (i.e. a receiver ID), and/or a transmitter address (i.e. transmitter ID). Data field <NUM> comprises the MAC protocol data unit (PDU). Moreover, the data field <NUM> is the field that is re-transmitted in a HARQ operation.

<FIG> illustrates schematically an example MAC PDU structure <NUM>, However, the invention is not limited to that and any MAC PDU structure may be used. The MAC PDU structure <NUM> comprises, a MAC header field, and one or more parts of MAC PDU data. The MAC header field is used to indicate to the receiving communication apparatus the content of the MAC PDU data as well as convey necessary parameters of a MAC level security (when used). The MAC level security is expected to cipher all other fields of the MAC PDU expect the MAC header field, whereas an integrity protection may be provided with a message integrity code (MIC) from the complete MAC PDU and added to end of the MAC PDU.

The transmitted packet <NUM> comprises the NIC <NUM> of the first communication apparatus <NUM>, i.e. the NIC <NUM> representing, i.e. identifying, the network <NUM> to which the first communication apparatus 102a belongs. The NIC <NUM> is divided in two parts, i.e. to a first part <NUM> and to a second part <NUM>. The first part of the NIC <NUM> comprises first x bits of the NIC <NUM>, wherein the x is the length of the first part of the NIC <NUM>. The second part of the NIC <NUM> comprises the rest y bits of the NIC <NUM>, wherein the y is the length of the second part of the NIC <NUM>. <FIG> illustrates schematically a simple example of a structure of the NIC <NUM> divided in the first part <NUM> and the second part <NUM>. According to a non-limiting example, if the total length of the NIC <NUM> is <NUM> bits and the length of the first part of the NIC <NUM> is <NUM> bits, the first part of the NIC <NUM> comprises <NUM> first bits of the NIC <NUM> and the second part of the NIC <NUM> comprises the last <NUM> bits of the NIC <NUM> as illustrated in the example of <FIG>. A header field <NUM> of the packet <NUM>, e.g. the PHY header field <NUM> in the example of <FIG>, comprises the first part of the NIC. The first part of the NIC <NUM> may be included in the header field <NUM> of the packet <NUM> as a plain text.

According to an example of the invention, the header field <NUM>, of the packet <NUM> may further comprise identification information representing, i.e. identifying, the transmitting apparatus, i.e. transmitter ID. Alternatively or in addition, the header field, <NUM>, of the packet <NUM> may further comprise identification information representing, i.e. identifying, the receiving apparatus, i.e. receiver ID <NUM>. The header field <NUM> may be protected with Cyclic Redundant Check (CRC) so that receiving apparatus, e.g. the second communication apparatus 102b, may ensure that reception of the PHY header field <NUM> was correct. The length of the CRC in PHY header field <NUM> may be e.g. <NUM> or <NUM> bits.

The second part of the NIC <NUM> is included in another field of the packet <NUM>. Preferably, the second part of the NIC <NUM> may be included in the data field <NUM> of the packet <NUM>. According to an example of the invention, the second part of the NIC <NUM> may be included in an error detection code of the data field <NUM> of the packet <NUM>. Preferably, the error detection code may be CRC. However, the invention is not limited to that and any other suitable error detection code may be used. The data field <NUM> may be protected with the CRC so that the receiving apparatus, e.g. the second communication apparatus 102b, may ensure, i.e. check, whether the reception of the data field <NUM>, i.e. the MAC PDU, was correct or not. This CRC may e.g. have length of <NUM> or <NUM> bits. The CRC of the data field <NUM> may be masked with the second part of the NIC <NUM>, i.e. the second part of the NIC <NUM> may be included in the CRC of the data field <NUM> of the packet <NUM>. In order to include the second part of the NIC <NUM> in the CRC of the data field <NUM> of the packet <NUM>, the first communication apparatus 102a performs a XOR operation for the second part of the NIC <NUM> with a conventional CRC, i.e. a CRC defined for the data field of the packet <NUM>. The conventional CRC may be defined for the data field of the packet <NUM> according to known techniques, e.g. based on a remainder of a polynomial division the content of the data field <NUM>. After the XOR operation the first communication apparatus 102a includes, i.e. applies, the result of the XOR operation, i.e. modified CRC, in the data field <NUM> of the transmitted packet as the error detection code, i.e. the CRC, (instead of the conventional CRC) for the receiving communication apparatus, e.g. the second communication apparatus 102b, to be used to check whether reception of the data field <NUM> of the packet <NUM> was correct or not. The CRC is preferable error detection code to which the second part of the NIC <NUM> may be included, because CRC enables substantially easy and fast execution, i.e. calculation, processes. Moreover, because the CRC of the data field <NUM> of the packet <NUM> is needed in any case to check, by the receiving apparatus, whether reception of the data field <NUM> of the packet <NUM> was correct or not, including the second part of the NIC <NUM> in the CRC does not cause extra effort. Moreover, the inclusion of the second part of the NIC <NUM> in the CRC of the data field of the packet <NUM> may be implemented by using only one additional XOR process in the transmitting communication apparatus and in the receiving communication apparatus. This enables a simple apparatus implementation.

According to an example of the invention, the second part of the NIC <NUM> may be combined with other set off identification bits, such as bits from the receiver ID, i.e. the receiver address, <NUM> before including the second part of the NIC <NUM> to the CRC of the data field <NUM>. <FIG> illustrates schematically an example of the structure of the NIC, wherein the second part of the NIC <NUM> is combined with <NUM> most significant bits of the receiver ID <NUM> as a single bit string. In this example, the length of the CRC of the data field <NUM> is <NUM> bits and the length of the second part of the NIC <NUM> is <NUM> bits. The second part of the NIC <NUM> and the <NUM> most significant bits of the receiver ID <NUM> may be combined as the single bit string so that in the XOR operation described above, the <NUM> most significant bits of the CRC are masked with the second part of the NIC <NUM> and then the <NUM> least significant part of the CRC is masked with the <NUM> most significant bits of the receiver ID <NUM>. The receiver ID may be e.g. <NUM> bits, where <NUM> least significant bits <NUM> are transferred in the header field <NUM> of the packet <NUM>, as a plain text or masked with the CRC of the PHY header field <NUM>, and the <NUM> most significant bits of the receiver ID <NUM> are used to mask CRC of the data part <NUM> of the packet <NUM>. Naturally, alternating exact number of bits or bit division between different set of bits may be possible.

According to an example of the invention, the size of the PHY header field <NUM> may be between <NUM> to <NUM> bits, even though other PHY header field <NUM> lengths are possible. Preferably, the size of the PHY header field <NUM> may be approximately between <NUM> to <NUM> bits. The size of the PHY header field <NUM> may depend on the format of the packet <NUM>. Alternatively or in addition, the size of the PHY header field <NUM> may depend on whether the CTF field may be used to transfer control channel bits or not. Above, it is discussed about the size of the PHY header field, but the same applies also to the header field of the packet <NUM>, if the packet is packet of any other layer. According to an example of the invention, the total length of the NIC may be <NUM>, <NUM>, or <NUM> bits.

Preferably, the total length of the NIC <NUM> may be <NUM> bits. Preferably, the length of the first part of the NIC <NUM> may be <NUM> bits or less causing that the length of the second part of the NIC <NUM> may be <NUM>, <NUM>, or <NUM> depending on the total length of the NIC <NUM>. Alternatively, the length of the first part of the NIC <NUM> may be <NUM> bits causing that the that the length of the second part of the NIC <NUM> may be <NUM> or <NUM> depending on the total length of the NIC <NUM>. Together the first part of the NIC <NUM> and the second part of the NIC <NUM> enables approximately several millions to billions unique NICs <NUM>. The use of <NUM> bit long first part of the NIC <NUM> reduces the overhead of the transmission at the PHY header field <NUM>. Moreover, the division of the NIC in two parts included in different fields of the packet <NUM> reduces the overhead of the transmission. Especially, in packets using substantially short slots the overhead of PHY header field <NUM> may be minimized to be able to use the short slots efficiently for application layer data. For example, DECT-<NUM> supports <NUM> channel bandwidth with <NUM> subcarrier spacing with only slot length of <NUM>/<NUM> = <NUM> (i.e. the frame time is <NUM> and the frame is split into <NUM> time slots).

At a step <NUM>, the second communication apparatus 102b receives a packet <NUM>. The received packet <NUM> may be the packet <NUM> transmitted by the first communication apparatus 102a or a packet transmitted by any other communication apparatus belonging to the same network, i.e. the network <NUM>, with the second communication apparatus 102b or belonging to another network, e.g. network <NUM>. The received packet <NUM> comprises the NIC <NUM> of the communication apparatus which transmitted the packet <NUM>, wherein the header field <NUM> of the packet <NUM> comprises the first part of the NIC <NUM> and the second part of the NIC <NUM> is included in another field of the packet <NUM> as discussed above referring to the transmitted packet <NUM>. For sake of simplicity, in this example the received packet may be considered to be the packet <NUM> transmitted by the first communication apparatus 102a and the above description about the transmitted packet <NUM> applies also to the received packet. However, the invention is not limited to that. As discussed above, the PHY header field <NUM> of the packet <NUM> is protected with CRC. The second communication apparatus 102b ensures that reception of the PHY header field <NUM> was correct based on the conventional CRC operation.

At a step <NUM>, the second communication apparatus 102b defines that the received packet <NUM> is from the network <NUM> to which the second communication apparatus 102b belongs. This may be called as a first definition step, wherein the second communication apparatus 102b compares the first part of the NIC <NUM> of the received packet <NUM> to the first part of the NIC <NUM> of the second communication apparatus 102b, i.e. the NIC representing, i.e. identifying, the network <NUM> to which the second communication apparatus 102b belongs. If the first part of the NIC <NUM> of the received packet <NUM> corresponds to the first part of the NIC <NUM> of the second communication apparatus 102b, the second communication apparatus 102b defines, at least provisionally, that the received packet <NUM> is from the network <NUM> to which the second communication apparatus 102b belongs, e.g. the packet <NUM> transmitted by the first communication apparatus 102a as discussed above. The inclusion of the NIC <NUM> to the PHY layer packet <NUM> enables that data from incorrect, i.e. wrong, networks is not forwarded to the higher layers, e.g. MAC layer, and it prevents acting on commands from incorrect networks. Moreover, this enables filtering out transmissions from incorrect networks as early as possible.

According to an example of the invention, if the first part of the NIC <NUM> of the received packet <NUM> differs from the first part of the NIC <NUM> of the second communication apparatus 102b, the second communication apparatus 102b may define that the received packet is from another network than the network <NUM> to which the second communication apparatus 102b belongs, e.g. from a communication apparatus <NUM> belonging to the second network <NUM>. This allows that the second communication device 102b may detect, if there are one or more other networks, e.g. the second network <NUM>, operating within the same environment using certain channel(s). Moreover, this is possible only by receiving the STFS field <NUM>, the CTF field <NUM>, and the PHY header field <NUM> of the packet <NUM>, and it is not necessary to receive the data field <NUM> of the packet <NUM> correctly or at all. This allows the second communication apparatus 102b to save energy as it may skip reception of the data field <NUM> of the packet <NUM>, if the received packet is from another network than the network <NUM> to which the second communication apparatus 102b belongs. In other words, this enables identification of the other networks operating on the same spectrum from each received packet, even though the data field <NUM> of the packet <NUM> would be ciphered and thus the content of the MAC PDU <NUM> could not be interpreted by the second communication apparatus 102b of the other network. Moreover, the second communication device 102b may obtain information representing activity of the one or more other networks based on at least one packet received from the one or more other networks. The information representing activity of the one or more other networks may comprise e.g. duty cycle and/or type of activity of the one or more other networks. The type of activity may be defined based on transmission type, e.g. broadcast or unicast, and/or periodicity of the transmissions. According to a non-limiting example, a detection of periodical transmissions from one communication apparatus belonging to another network, e.g. in every <NUM> milliseconds, <NUM> milliseconds, or <NUM> milliseconds with gaps between, may indicate an audio type system operation. The second communication device 102b may e.g. detect that the periodical transmissions are transmitted by one communication apparatus belonging to the other network based on the transmitter ID included in the PHY header field <NUM>. According to another non-limiting example, a detection of a short transmission with a random interval from different communication apparatuses belonging to the same other network at certain channel may indicate a massive Internet of Things (IoT) type system operation. The identification of the other networks operating on the same spectrum enables that the communication apparatuses may recognize which networks and what type of transmissions are causing interference at specific channels, which cannot be done with a simple received signal strength indicator (RSSI) measurement typically used to avoid operating in highly interfered channels. For example, the DECT-<NUM> requires that devices have cognitive radio capabilities to avoid operating in highly interfered channels. Thus, the identification of the other networks operating on the same spectrum improves the cognitive radio capabilities of the communication apparatuses.

According to an example of the invention, if the header field <NUM> of the received packet <NUM> further comprises the transmitter ID and/or the receiver ID <NUM>, the second communication apparatus 102b may perform a further confirmation at a step <NUM>. This further confirmation may be performed after the definition that the received packet <NUM> is from the network <NUM> to which the second communication apparatus 102b belongs based on the first part of the NIC <NUM> included in the header field <NUM> of the packet <NUM> at the step <NUM>. At a step <NUM> the second communication apparatus 102b performs the further confirmation that the received packet <NUM> is from the network <NUM> to which the second communication apparatus 102b belongs based on the transmitter ID and/or the receiver ID <NUM>. This may be called as a second definition step, wherein the second communication apparatus 102b compares the transmitter ID and/or the receiver ID <NUM> included in the PHY header field <NUM> to the respective transmitter ID and/or receiver ID known by the second communication apparatus 102b from PHY header. If the compared transmitter IDs and/or receiver IDs <NUM> correspond with each other, the second communication apparatus 102b performs a second definition that the received packet <NUM> is from the network <NUM> to which the second communication apparatus belongs, e.g. the packet <NUM> transmitted by the first communication apparatus 102a as discussed above. For example, if the receiver ID <NUM> included in the PHY header field <NUM> of the received packet <NUM> is different than the receiver ID <NUM> of the second communication apparatus 102b, the second communication apparatus 102b may define that the received packet is not destinated to the second communication apparatus 102b.

At a step <NUM>, in response to definition that the received packet <NUM> is from the network <NUM> to which the second communication apparatus 102b belongs at the step <NUM> or <NUM>, the second communication apparatus 102b performs an error check to ensure whether the reception of the data field <NUM> of the received packet <NUM>, i.e. the MAC PDU, was correct or not. As discussed above the second part of the NIC <NUM> may be included in the error detection code of the data field <NUM> of the packet <NUM>. Preferably, the second part of the NIC <NUM> is included in the CRC of the data field <NUM> of the packet <NUM>. To ensure that the communication apparatus 102b is the correct intended receiver of the received packet <NUM>, the second communication apparatus 102b performs a reverse CRC operation. In other words, to ensure that the reception of the data field <NUM> of the received packet <NUM> was correct, the second communication apparatus 102b performs a XOR operation for the second part of the NIC <NUM> with the CRC defined for the data field <NUM> of the received packet <NUM> and compares the result of the XOR operation to the CRC included in the data field <NUM> of the received packet <NUM>. If the result of the XOR operation corresponds with the CRC included in the data field <NUM> of the received packet <NUM>, the second communication apparatus 102b defines that the reception of the packet was correct and the second communication apparatus 102b is the correct intended receiver of the packet <NUM>, i.e. the packet <NUM> was intended for the second communication apparatus 102b. If the result of the XOR operation does not correspond with the CRC included in the data field <NUM> of the received packet <NUM>, the second communication apparatus 102b defines that the reception of the packet <NUM> was incorrect. Alternatively, the second communication apparatus 102b may perform a XOR operation for the second part of the NIC <NUM> with the CRC included in the data field <NUM> of the received packet <NUM> and compares the result of the XOR operation to the CRC defined for the data field <NUM> of the received packet <NUM>. If the result of the XOR operation corresponds with the CRC defined for the data field <NUM> of the received packet <NUM>, the second communication apparatus 102b defines that the reception of the packet was correct and the second communication apparatus 102b is the correct intended receiver of the packet <NUM>, i.e. the packet <NUM> was intended for the second communication apparatus 102b. If the result of the XOR operation does not correspond with the CRC defined for the data field <NUM> of the received packet <NUM>, the second communication apparatus 102b defines that the reception of the packet <NUM> was incorrect. This enables that the second communication apparatus 102b may ensure that with a wrong NIC <NUM>, e.g. NIC of another network than the network to which the second communication apparatus 102b belongs, the reception of the packet is never correct. This, in turn, reduces the possibility of acting or passing data included in the data field <NUM> of the received packet <NUM> to higher layers, e.g. MAC layer, from an incorrect network. The definition of the incorrect reception may be due to errors in bits string or due to wrong NIC <NUM>, but in both cases the reception is not correct, and the data included in the data field <NUM> of the received packet <NUM>, is not passed to the higher layers.

According to an example of the invention, if the CRC of data field <NUM> of the packet <NUM> is masked with the second part of the NIC <NUM> combined with the most significant bits of the receiver ID <NUM> as discussed above referring to example of <FIG>, the second communication apparatus 102b may perform the reverse CRC operation similarly as discussed above with addition that the second part of the NIC <NUM> and the <NUM> most significant bits of the receiver ID <NUM> are combined as the single bit string so that in the XOR operation described above, the <NUM> most significant bits of the CRC are masked with the second part of the NIC <NUM> and then the <NUM> least significant part of the CRC is masked with the <NUM> most significant bits of the receiver ID <NUM> to ensure that the communication apparatus 102b is the correct intended receiver of the received packet <NUM>.

According to an example of the invention, in response to detection of a correct reception of the packet at the step <NUM>, the second communication apparatus 102b may determine a message indicating a correct reception of the packet <NUM> to be transmitted to the communication apparatus, from which the packet <NUM> is received, e.g. first communication apparatus 102a. According to an example, the message indicating the correct reception may be e.g. an acknowledgement (ACK) signal. Alternatively, in response to the detection of an incorrect reception of the packet <NUM> at the step <NUM>, the second communication apparatus 102b may determine a message indicating an incorrect reception of the packet <NUM> to be transmitted to the communication apparatus, from which the packet <NUM> is received, e.g. first communication apparatus 102a. According to an example, the message indicating the incorrect reception may be e.g. a negative-acknowledgement (NACK) signal. In response to receiving the message indicating the incorrect reception of the packet <NUM>, the transmitting apparatus, e.g. the first communication apparatus may re-transmit the packet <NUM>.

There may exists a minor possibility that the first part of the NIC <NUM>, the transmitter ID and the receiver ID <NUM> included in the header field <NUM> of a packet <NUM> received from another network matches with the first part of the NIC <NUM> of the second communication device 102b and the transmitter ID and the receiver ID <NUM> known by the second communication apparatus 102b. In this case the second communication apparatus 102b may consider the packet transmitted from another network, e.g. from the second network <NUM>, to be valid for the second communication apparatus 102b, but the error check at the step <NUM> fails, because the second part of the NIC <NUM> of the other network does not correspond to the second part of the NIC <NUM> of the second communication apparatus 120b and as discussed above with the wrong NIC <NUM> the reception of the packet <NUM> is never correct. In response to defining that the reception of the packet was incorrect, the second communication apparatus 102b may transmit the message indicating the incorrect reception, e.g. NACK, to the communication apparatus that transmitted the packet <NUM>. Additionally, if the CRC of data field <NUM> of the packet <NUM> is masked with the second part of the NIC <NUM> combined with the most significant bits of the receiver ID <NUM> as discussed above, the possibility that a receiving communication apparatus from the same network, i.e. using the correct NIC, receives a packet <NUM> that is not intended for it may further be reduced as the receiver ID comprising <NUM> bits in the PHY header field with the additional <NUM> bits in the CRC of the data field <NUM>, having total of <NUM> bit resulting over <NUM> million addresses.

According to an example of the invention, if the received packet is a uncast transmission, the transmission of the message indicating the incorrect reception, e.g. NACK, may be omitted, if the transmitter ID included in the header field <NUM> of the received packet <NUM> does not match with the transmitter ID of the communication apparatus with which the second communication apparatus 102b has associated. The uncast transmission may be applied between two apparatuses that have associated with each other. There may also be a minor possibility that an incorrect receiving communication apparatus transmits a NACK transmission. The transmitting communication apparatus may then receive one or more NACKs. One from the incorrect communication apparatus, which belongs to another network, and one from a correct receiving communication apparatus belonging to the same network with the transmitting communication apparatus. Alternatively, the transmitting communication apparatus may receive an ACK from a correct receiving communication apparatus belonging to the same network with the transmitting communication apparatus and a NACK from the incorrect communication apparatus, which belongs to another network. In the first case retransmission of the packet <NUM> is any how applied, because no ACK is received at the transmitting communication apparatus of the packet <NUM>. In the latter case the transmitting communication apparatus may stop the re-transmissions as it has received the ACK. There may also be possibility that the transmitting communication apparatus does not receive neither ACK or NACK, because the feedback, i.e. ACK or NACK, transmissions comprising a HARQ feedback might be colliding. In this case the transmitting communication apparatus may apply re-transmission as it may assume that the reception of the PHY header field <NUM> was not correct. This may be a very rare case and not permanent transmission state and if it continues the transmitting communication apparatus may stop transmission of the packet to that receiving communication apparatus and consider that radio communication failed, which is more typically happening due to extensive path loss or high interference conditions. However, the possibility that the transmitting communication apparatus would receive ACK from wrong receiving communication apparatus may be avoided.

As the reception is never correct with a wrong NIC <NUM>, the receiving apparatuses, e.g. the second communication apparatus 102b, need to be aware of the first part of the NIC <NUM> and the second part of the NIC <NUM>. In other words, the network <NUM> has a process to provide the first part of the NIC <NUM> and the second part of the NIC <NUM> to the communication apparatuses <NUM> belonging to the network <NUM>. According to an example, this may be provided by configuration of the communication apparatus or by other communication method, such as by using Near Field Communication (NFC). Alternatively or in addition, the network <NUM> itself may provide this by supporting a network beacon message, i.e. a system information broadcast, that may be send with a PHY header field that may comprise, but is not limited to, the first part of the NIC <NUM>. Additionally, the CRC of the data field of the beacon message is not masked with second part of the NIC <NUM>, i.e. the data field of the beacon message does not include the second part of the NIC <NUM>, rather it is not masked at all or is masked with a pre-defined value that may be given in network standard. The actual MAC PDU of the beacon message then contains both parts of the NIC <NUM>, either separately coded (i.e. two separate fields) or as a single field, wherein the first x bits are used as the first part of the NIC <NUM> and the rest y bits are used as the second part of the NIC <NUM>. The x is the length of the first part of the NIC <NUM> as discussed above. The y is the length of the second part of the NIC <NUM> as discussed above. This allows the network to change the used NIC <NUM>, e.g. in a case that the network identifies that there is collision in the first part of the NIC <NUM> or in the complete NIC <NUM>. Alternatively, the receiving communication apparatus may obtain the first part of the NIC <NUM> from the PHY header field and the second part of the NIC <NUM> from data field of the beacon message. Only the communication apparatuses <NUM> desiring to operate in that network may act on the beacon message and other communication apparatuses may ignore the beacon message. The beacon message may further comprise an actual, i.e. long, network ID, such as PLMN ID or Service set identifier (SSID), that is human readable. The network according to the invention may operate so that it transmits the actual network ID, such as PLMN ID or SSID in a system information broadcast in a cellular network or in beacon in a WLAN network, in addition to the NIC <NUM>. This enables that the NIC <NUM> may be local even though the actual network ID is global.

According to an example of the invention, the NIC <NUM> may be independent from the actual Network ID, such as SSID or PLMN ID. Alternatively, the NIC <NUM> may be derived from the actual Network ID or it may be directly the actual Network <NUM>.

<FIG> illustrates an example of a communication apparatus (device) <NUM>, 102a, 102b, <NUM> according to the invention. The communication apparatus <NUM>, 102a, 102b, <NUM> comprises a processing part <NUM> that is configured to perform user and/or computer program (software) initiated instructions, and to process data in order to run an application and communication protocol. The processing part <NUM> may comprise at least one processor, e.g. one, two, or three processors. The communication apparatus <NUM>, 102a, 102b, <NUM> further comprises a memory part <NUM> in order to store and to maintain data. The data may be instructions, computer programs, and data files. The memory part <NUM> may comprise at least one memory, e.g. one, two, or three memories.

The communication apparatus <NUM>, 102a, 102b, <NUM> further comprises a data transfer part <NUM> and an antenna part <NUM>. The communication apparatus <NUM>, 102a, 102b, <NUM> uses the data transfer part <NUM> in order to transmit commands, requests, messages, and data to at least one of other communication apparatuses of the wireless communication network <NUM>, <NUM> via the antenna part <NUM>. The data transfer part <NUM> also receives commands, requests, messages, and data from at least one of the other communication apparatus <NUM>, 102a, 102b, <NUM> via the antenna part <NUM>. The communication apparatus <NUM>, 102a, 102b, <NUM> may further comprises a power supply part <NUM>. The power supply part <NUM> comprises components for powering the communication apparatus <NUM>, 102a, 102b, <NUM>, e.g. a battery and a regulator.

The memory part <NUM> comprises a data transfer application for operating, i.e. controlling, the data transfer part <NUM>, an antenna application for operating the antenna part <NUM>, and a power supply application for operating the power supply part <NUM>.

The memory part <NUM> comprises also an application <NUM>, i.e. a computer program, comprising instructions which, is configured to use at least one of parts <NUM>, <NUM>, <NUM> in order to perform, i.e. carry out, at least the operations, i.e. the method steps, of the communication apparatus <NUM>, 102a, 102b, <NUM> described above in this description part and figures, when it is run, i.e. executed, by a computer, e.g. by the communication apparatus <NUM>, 102a, 102b, <NUM> by means of the processing part <NUM>.

The computer program may be stored in a non-statutory tangible computer readable medium, e.g. an USB stick or a CD-ROM disc.

The invention relates also to the wireless communication network (system) <NUM>, <NUM> comprising a plurality of communication apparatuses comprising the first communication apparatus 102a and the second communication apparatus 102b described above. Each communication apparatus of the system <NUM>, <NUM> is configured to provide a bi-directional radio communication with at least one other communication apparatus of the system <NUM>, <NUM>. The wireless communication network <NUM>, <NUM> according to the invention may be, but is not limited to, BLE mesh network, Thread network, Zigbee network, Public Land Mobile Network (PLMN), WLAN network, cellular network, wireless mesh network, etc.. The wireless communication apparatus <NUM>, 102a, 102b, <NUM> according to the invention may be any wireless device comprising, but not limited to, a mobile device, a node device, a router, a repeater, etc..

As an alternative to including the first part of the NIC <NUM> to the header field <NUM> of the packet <NUM> and the second part of the NIC <NUM> to the CRC of the data field <NUM> of the packet <NUM>, the NIC <NUM> could be included e.g. in the MAC PDU included in the data field <NUM> of the packet <NUM> as a normal pay-load, which enables simple transmission of the NIC <NUM>. However, the communication technique used in the network may support MAC layer security, wherein the MAC PDU comprises the MIC and the MAC PDU is encrypted, expect the very beginning of the packet, i.e. MAC header field, which are used in decrypting process. The MAC level security is preferable especially in a mesh network operation in order to enable the receiving computing apparatus to check that the packet is legitimate before forwarding the packet forward in the mesh network. Therefore, if the NIC <NUM> is included e.g. in a ciphered part of the MAC PDU, the receiving communication apparatus needs to perform deciphering and integrity protection, e.g. MIC, check procedures for all received packets before it may decide whether the received packet is from the same network to which the receiving communication apparatus belongs or from another network. The deciphering and process integrity check procedures require significantly more processing than performing the simple check based on the CRC of the data field as discussed above. Thus, in addition to not acting on wrong packets at higher levels at least some embodiments of the invention enable avoiding unnecessary deciphering and integrity check procedures at MAC layer of the receiving communication apparatus, which in turn improves the power consumption of the receiving communication apparatus. In other words, the early packet filtering from the header field of packets from other networks enables optimizing the power consumption of the receiving communication apparatus, because decoding processes of another network MAC PDUs may be minimized. Moreover, including the second part of the NIC <NUM> in the CRC of the data field <NUM> of the packet <NUM> by performing the XOR process in the transmitting communication apparatus and in the receiving communication apparatus as discussed above, enables substantially faster definition, i.e. calculation, process than the calculating process of the MIC and may it be performed before transmitting the HARQ feedback (HARQ ACK or HARQ NACK) in the HARQ operation. The HARQ operation, i.e. HARQ combining, is known as an efficient method to reduce Block Error Rate (BLER) of the transmission. At least some embodiments of the present invention described above enables that the receiving communication apparatus of an incorrect network will never send any HARQ ACK message in the HARQ operation. When the transmission is a broadcast or a multicast transmission, the receiving communication apparatuses do not apply the HARQ operation and thus do not send the ACK or NACK message and the receiver ID may be set as a known value.

Claim 1:
A communication apparatus (<NUM>, 102a, 102b, <NUM>) comprising
a processor part (<NUM>), and
a data transfer part (<NUM>),
wherein the apparatus (<NUM>, 102a, 102b, <NUM>) is configured to:
receive, by the data transfer part (<NUM>), a packet (<NUM>) comprising a network identification code, NIC, (<NUM>) of a communication apparatus that transmitted the packet (<NUM>), wherein a header field (<NUM>) of the packet (<NUM>) comprises a first part of the NIC (<NUM>) and a second part of the NIC (<NUM>) is included in another field of the packet (<NUM>), and
define, by the processor part (<NUM>), that the received packet (<NUM>) is from a network (<NUM>, <NUM>) to which the communication apparatus (<NUM>, 102a, 102b, <NUM>) belongs, if the first part of the NIC (<NUM>) of the received packet (<NUM>) corresponds to the first part of the NIC (<NUM>) of said communication apparatus (<NUM>, 102a, 102b, <NUM>),
characterized in that the apparatus (<NUM>, 102a, 102b, <NUM>) is further configured to:
perform an error check to ensure whether the reception of the data field (<NUM>) of the received packet (<NUM>), was correct or not, in response to the definition that the received packet (<NUM>) is from the network (<NUM>, <NUM>) to which the communication apparatus (<NUM>, 102a, 102b, <NUM>) belongs,
wherein the reception of the packet (<NUM>) is incorrect, if the second part of the NIC (<NUM>) of the received packet (<NUM>) does not correspond to the second part of the NIC (<NUM>) of said communication apparatus (<NUM>, 102a, 102b, <NUM>).