TECHNICAL FIELD

Embodiments herein relate to network node operation in a wireless

communications network. In particular, embodiments herein relate to network nodes and a methods therein for operating on one or more frequency bands in wireless

communications network. BACKGROUND

In the standardized IEEE 802.1 1 Wreless LAN, WLAN, which commonly also may be referred to as a Wi-Fi network, a Basic Serving Set, BSS, is regarded the basic building block of this wireless communications network. The BSS comprise an Access Point, AP, and a number of stations, STAs, located within a certain coverage area or cell being served by the AP. Within a BSS, the transmission between the AP and the STAs is typically performed in a distributed manner. This means that before a transmission, a STA may first sense the transmission medium for a specific period of time. If the transmission medium is deemed idle, then access may be assigned to this STA for transmission;

otherwise, the STA typically has to wait a random back-off period and then again check whether the transmission medium is idle and thus available to the STA. The random backoff period provides a collision avoidance mechanism for multiple STAs that wish to transmit within the same BSS. The standardized IEEE 802.11 WLAN may thus be seen as one example of a wireless communications network using contention-based transmission resources.

At the 2.4 GHz Industrial, Scientific and Medical, ISM, frequency band, a number of non-overlapping channels may be allocated for an IEEE 802.1 1 WLAN. Fig. 1 illustrates the allocation of three or four non-overlapping channels which are regulated in most countries. These channels are frequency bands with a 20 MHz bandwidth.

When a new AP is deployed, the least used channel in its neighbourhood should be selected in order to minimize interference and maximize capacity. The channel allocation may be configured manually or selected automatically by the new AP. With automatic channel selection, a new AP may actively scan the radio environment by listening to broadcasted beacons from nearby APs in the different channels. The beacon frames of the beacon are broadcasted by each AP periodically and comprise information useful for the channel selection of the new AP. For example, BSS load elements in the beacon frame may provide knowledge on associated ST A counts and channel utilization. Hence, during the initial setup phase, the new AP may avoid channels already in use by many nearby APs by scanning the beacons. The new AP may also switch to other channels during operation if the current channel is too crowded and a less congested channel is detected.

Furthermore, developments are being made to introduce APs that besides operating on the conventional 20 MHz frequency band may also be able to simultaneously operate on smaller frequency sub-bands, such as, e.g. a 2 MHz frequency band. These WLANs may be referred to as narrow-band capable WLANs. Correspondingly, STAs may also be introduced in such WLANs that will be able to operate on and decode signals of these smaller frequency sub-bands. However, these STAs may then not be capable of operating on or decode signals of the conventional 20 MHz frequency band. In the same way, conventional STAs currently operating on the conventional 20 MHz frequency band may not be capable of operating on or decode signals of the newly introduced smaller frequency sub-bands.

However, since these narrow-band capable WLANs may provide different radio coverage areas for the conventional wider frequency bands and the smaller frequency bands, co-existence problems may arise. For example, a conventional APs that is located outside the radio coverage area of the conventional wider frequency bands, but within the radio coverage area of the smaller frequency bands, of a newly introduced narrow-band capable AP may be unaware of the existence of the newly introduced narrow-band capable AP. This may affect the performance of the conventional APs operation on the conventional wider frequency bands. SUMMARY

It is an object of embodiments herein to improve network node operation on one or more frequency bands in a wireless communications network.

According to a first aspect of embodiments herein, the object is achieved by a method performed by a first network node for enabling at least one third node to operate on one or more frequency bands in a wireless communications network. The first network node detects the presence of a second network node in the wireless communications network, wherein the second network node separately operates on said one or more frequency bands within a first radio coverage area and on one or more frequency sub- bands within a second radio coverage area, wherein said one or more frequency sub- bands are smaller than and forms a part of any of said one or more frequency bands. Then, the first network node transmits information to at least one third network node in the wireless communications network indicating the presence of the second network node. According to a second aspect of embodiments herein, the object is achieved by a first network node for enabling at least one third node to operate on one or more frequency bands in a wireless communications network. The first network node is configured to detect the presence of a second network node in the wireless

communications network, wherein the second network node separately operates on said one or more frequency bands within a first radio coverage area and on one or more frequency sub-bands within a second radio coverage area, wherein said one or more frequency sub-bands are smaller than and forms a part of any of said one or more frequency bands. The first network node is also configured to transmit information to at least one third network node in the wireless communications network indicating the presence of the second network node.

According to a third aspect of embodiments herein, the object is achieved by a method performed by a third network node for operating on one or more frequency bands in a wireless communications network. The third network node receives, from a first network node, information indicating the presence of a second network node in the wireless communications network, wherein the second network node separately operates on said one or more frequency bands within a first radio coverage area and on one or more frequency sub-bands within a second radio coverage area, wherein said one or more frequency sub-bands are smaller than and forms a part of any of said one or more frequency bands. Then, the third network node adapts transmissions from the third network node on said one or more frequency bands based on said received information.

According to a fourth aspect of embodiments herein, the object is achieved by a third network node for operating on one or more frequency bands in a wireless communications network. The third network node is configured to receive, from a first network node, information indicating the presence of a second network node in the wireless communications network, wherein the second network node separately operates on said one or more frequency bands within a first radio coverage area and on one or more frequency sub-bands within a second radio coverage area, wherein said one or more frequency sub-bands are smaller than and forms a part of any of said one or more frequency bands. The third network node is also configured to adapt transmissions from the third network node on said one or more frequency bands based on said received information. According to a fifth aspect of embodiments herein, the object is achieved by a computer program, comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out the methods described above. According to a sixth aspect of embodiments herein, the object is achieved by a carrier containing the computer program described above, wherein the carrier is one of an electronic signal, optical signal, radio signal, or computer readable storage medium.

By having a first network node, said first network node being located within the first radio coverage area of the one or more frequency bands of a second network node, detect and signal the presence of the second network node to a third network node, said third network node being located outside the first radio coverage area of the one or more frequency bands of the second network node but within the second radio coverage area of one or more frequency sub-bands of the second network node, the third network node may be made aware of the presence of the second network node in the wireless communications network. Hence, the third network node may use the information about the second network node and adapt its transmissions accordingly. Hence, the operation of the third network node on one or more frequency bands in the wireless communications network is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

Features and advantages of the embodiments will become readily apparent to those skilled in the art by the following detailed description of exemplary embodiments thereof with reference to the accompanying drawings, wherein:

Fig. 1 is a schematic block diagram illustrating non-overlapping frequency bands for use in a wireless communications network,

Fig. 2 is a schematic block diagram illustrating embodiments of a first and a third network node in a wireless communications network,

Fig. 3 is a flowchart depicting embodiments of a method in a first network node,

Fig. 4 is a flowchart depicting embodiments of a method in a third network node, Fig. 5 is a schematic block diagram depicting embodiments of a first network node, and

Fig. 6 is a schematic block diagram depicting embodiments of a third network node.

DETAILED DESCRIPTION

The figures are schematic and simplified for clarity, and they merely show details which are essential to the understanding of the embodiments presented herein, while other details have been left out. Throughout, the same reference numerals are used for identical or corresponding parts or steps.

Fig. 2 shows an example of a wireless communications network 100 in which embodiments herein may be implemented. The wireless communications network 100 in Fig. 2 comprise three Wireless Local Area Networks, WLANs. The WLANs may each comprise one or more Access Points, APs, configured to provide WLAN coverage and serve stations, STAs, located within their respective radio coverage area or cell. The WLANs may operate on the 2.4 GHz ISM frequency band or other ISM frequency bands. The APs may also be referred to herein as network nodes or base stations, and the STAs may also be referred to herein as wireless devices, terminals or user devices, UEs.

In the example scenario of Fig. 2, the first WLAN comprise a first network node

110, the second WLAN comprise a second network node 111 , and the third WLAN comprise a third network node 112. The first network node 110 may be configured to provide WLAN coverage and serve stations, STAs, on one or more of the conventional channels or frequency bands of the IEEE 802.1 1 standard, e.g. one or more of the 20 MHz frequency bands indicated in Fig. 1 , within the radio coverage area or cell 135 indicated by the dashed area in Fig. 2. The second network node 1 11 may be configured to provide WLAN coverage and serve stations, STAs, on one or more of the conventional channels or frequency bands of the IEEE 802.11 standard within the radio coverage area or cell 136 indicated by the dotted area in Fig. 2. The third network node 1 12 may be configured to provide WLAN coverage and serve stations, STAs, on one or more of the conventional channels or frequency bands of the IEEE 802.11 standard within the radio coverage area or cell 137 indicated by the dash-dotted area in Fig. 2.

In some cases, the first, second and third network nodes 110-112 may be a network node that forms part of a cellular, wireless or radio communication system providing radio coverage to the STAs over cellular transmission resources. Examples of such cellular, wireless or radio communication systems are, for example, LTE, LTE- Advanced, Wideband Code-Division Multiple Access (WCDMA), Global System for Mobile communications/Enhanced Data rate for GSM Evolution (GSM/EDGE), Worldwide Interoperability for Microwave Access (WMax), Ultra Mobile Broadband (UMB) or GSM network, or other cellular networks or systems. Here, the first, second and third network nodes 110-112 may e.g. be eNBs, eNodeBs, or a Home Node Bs, a Home eNode Bs, femto Base Stations (BSs), pico BSs or any other network units capable to serve wireless devices or STAs on cellular transmission resources in the wireless communications network 100. The first, second and third network nodes 110-112 may also be e.g. radio base stations, base station controllers, network controllers, relay nodes, repeaters, Ultra- Dense Network/Software-Defined Network (UDN/SDN) radio access nodes, Remote Radio Units (RRUs) or Remote Radio Heads (RRHs). In these cases, the first, second and third network nodes 110-1 12 may also be referred to as parts of the cellular, wireless or radio communication system being configured to operate in parts of the so-called unlicensed spectrum, i.e. unlicensed frequency bands which are shared, decentralized and not licensed to a particular type of scheduled wireless or radio communication.

In the example scenario of Fig. 2, the second network node 1 1 1 may further be configured to simultaneously operate on one or more sub-channels or frequency sub- bands that are smaller than the one or more conventional channels or frequency bands according to the IEEE 802.1 1 standard. Hence, the second network node 11 1 may be referred to as narrow-band capable network node or AP. The one or more sub-channels or frequency sub-bands may also form part of the one or more conventional channels or frequency bands, such as, e.g. one or more 2 MHz sub-channels or frequency sub-bands located within one or more of the conventional 20 MHz channels, frequency bands of the 2.4 GHz ISM frequency band according to the IEEE 802.1 1 standard, or other ISM frequency bands. Furthermore, in the example scenario of Fig. 2, the second network node 11 1 is configured to provide WLAN coverage and serve stations, STAs, on one or more sub-channels or frequency sub-bands within the radio coverage area or cell 136' indicated by the dotted area in Fig. 2.

Here, it should be noted that the radio coverage area or cell of the one or more frequency sub-bands of the second network node 11 1 and the transmission power of signals transmitted within these one or more frequency sub-bands by the second network node 11 1 may be different than the radio coverage area or cell of the one or more conventional frequency bands of the second network node 11 1 and the transmission power of signals transmitted within these one or more conventional frequency bands of the second network node 11 1 , respectively. In some cases, the second network node 1 1 1 may be referred to as a Long Range Low Power, LRLP, capable network node or LRLP AP. This is because, in some cases, the radio coverage area or cell of the one or more sub-channels or frequency sub-bands of the second network node 1 11 may be larger than 5 the radio coverage area or cell of the one or more conventional frequency bands of the second network node 11 1 , while the transmission power of signals transmitted within these one or more sub-channels or frequency sub-bands by the second network node 1 11 are lower than the transmission power of signals transmitted within these one or more conventional channels or frequency bands of the second network node 11 1 , respectively.

10 The current IEEE 802.1 1 ax standard is a technology based on Orthogonal

Frequency-Division Multiple Access, OFDMA, and uses a 20 MHz basic carrier bandwidth. This means that it has a minimum Resource Unit, RU, size of 26 tones, whereby each tone is about 2 MHz, i.e. -2.03 MHz. Thus, nine RUs are possible per 20 MHz frequency band. Since a single RU may be allocated to a specific STA, the carrier

15 frequency of the one or more sub-channels or frequency sub-bands may come to overlap with one of the RU carrier frequencies being used by a BSS according to the current IEEE 802.1 1ax standard. This means that 2 MHz sub-channels or frequency sub-bands may be suitably used by the second network node 11 1 , e.g. a LRLP AP.

In the example scenario of Fig. 2, a first and a second station, STA 121, 121',

20 are located within the radio coverage area or cell 137 of one or more of the conventional channels or frequency bands of the IEEE 802.11 standard provided by the third network node 112. The first STA 121 is wireless device configured to operate on and decode signals on the one or more of the conventional channels or frequency bands of the IEEE 802.1 1 standard provided by the third network node 112. Hence, the first STA 121 may be

25 served by the third network node 1 12 within the radio coverage area or cell 137. However, by being configured to operate on and decode signals on the one or more of the conventional channels, the first STA 121 is unable to operate on and decode signals on the one or more sub-channels or frequency sub-bands provided by the second network node 1 11 within the radio coverage area or cell 136'. On the other hand, the second STA

30 121 ' is a wireless device configured to operate on and decode signals on the one or more sub-channels or frequency sub-bands provided by the second network node 1 11 within the radio coverage area or cell 136'. Hence, the second STA 121 ' may be served by the second network node 11 1 within the radio coverage area or cell 136'. Thus, by being configured to operate on and decode signals on the one or more sub-channels or

35 frequency sub-bands, the second STA 121 ' is unable to operate on and decode signals on the one or more of the conventional channels or frequency bands of the IEEE 802.11 standard provided by the third network node 1 12. Hence, in some cases, the first STA 121 may be referred to as a legacy STA and the second STA 121 ' as an LRLP STA.

It should also be noted that the first and second STA 121 , 121 ' may e.g. be any kind of stations or wireless devices capable of communication via a WiFi/WLAN. For example, the first and second STA 121 , 121 ' may be mobile phones, cellular phones, Personal Digital Assistants (PDAs), smart phones, tablets, sensors or actuators with wireless communication capabilities, sensors or actuators connected to or equipped with wireless devices, Machine Devices (MDs), Machine-Type-Communication (MTC) devices, Machine-to-Machine (M2M) communication devices, wireless devices with D2D capability, Customer-Premises Equipments (CPEs), Laptop-Mounted Equipments (LMEs), Laptop- Embedded Equipments (LEEs), etc. In the example scenario of Fig. 2, the second AP 11 1 and the second STA 121 ' may be referred as a first Basic Service Set, BSS, and the third AP 1 12 and the first STA 121 may be referred to as a second BSS.

Furthermore, although embodiments below are described with reference to Fig. 3, this should not be construed as limiting to the embodiments herein, but merely as an example made for illustrative purposes. It should also be noted that although the description of the embodiments herein is made in view of the IEEE 802.1 1 standard, along with specific examples regarding different amendments already developed or under development, the embodiments may also be applicable to other standards, as well as, for future amendments of IEEE 802.11 standard.

As part of the developing of the embodiments described herein, it has been noticed that there may occur instances in which the co-existence between network nodes operating on conventional channels, e.g. 20 MHz channel bandwidths, and network nodes operating on both conventional channels and on sub-channels, e.g. 2 MHz channel bandwidths, in the wireless communications network may cause problems.

For example, a LPRP AP, such as, e.g. the second network node 11 1 in Fig. 2, may operate on both a 20 MHz and a 2 MHz bandwidth, wherein the radio coverage area for the 2 MHz bandwidth with LRLP STAs, such as, e.g. the second STA 121 ' in Fig. 2, may be larger. While legacy APs, such as, e.g. the first network node 110 in Fig 2, and legacy STAs, such as, e.g. the first STA 121 in Fig. 2, may be able to detect

transmissions on the 20 MHz bandwidth from the LRLP AP when located within the radio coverage area or cell of the 20 MHz bandwidth of the LRLP AP, the transmissions on the 2 MHz bandwidth beyond the radio coverage area or cell of the 20 MHz bandwidth will be un-decodable interference to these legacy APs and STAs. Besides, transmissions from LRLP STAs, such as, the second STA 121', are not able to be decoded by legacy APs or STA at all. This implies that within the radio coverage area or cell of the 2 MHz bandwidth of the LRLP AP, the existence or presence of the LRLP AP and the first BSS may be 5 undetectable to a large number of legacy APs in the wireless communications network. This means, for example, that a legacy AP, such as, e.g. the third network node 112, performs its channel selection, the existence or presence of the LRLP AP or the first BSS cannot be taken into consideration. Consequently, the channel selection of this legacy AP will not be optimal in the absence of such consideration.

10 This issue is addressed by the embodiments presented herein by having the first network node 110 detect and signal the presence of the second network node 1 11 to the third network node 1 12, the third network node 112 may thus be made aware of the presence of the second network node 1 11 in the wireless communications network 100. Hence, the third network node 1 12 may use the information about the second network

15 node 11 1 and adapt its transmissions accordingly. Hence, the operation of the third

network node 112 on one or more frequency bands in the wireless communications network 100 is improved.

20 Example of embodiments of a method performed by a first network node 1 10 for enabling at least one third network node 112 to operate on one or more frequency bands in a wireless communications network 100 will now be described with reference to the flowchart depicted in Fig.3. Fig. 3 illustrates an example of actions or operations which may be taken by the first network node 110 as shown in Fig. 5. The method may comprise

25 the following actions.

Action 301

Optionally, the first network node 110 may receive information from the at least one third network node 1 12 requesting information indicating if a second network node 30 1 11 has been detected by the first network node 110 in the wireless communications network 100. Alternatively, in some embodiments, the first network node 1 10 may also detect the presence of the at least one third network node 1 12.

Action 302 The first network node 110 detects the presence of a second network node 1 11 in the wireless communications network 100. Here, the second network node 11 1 separately operates on said one or more frequency bands within a first radio coverage area 136 and on one or more frequency sub-bands within a second radio coverage area 136', wherein 5 said one or more frequency sub-bands are smaller than and forms a part of any of said one or more frequency bands.

According to one example, as shown in the example scenario of Fig. 2, this may be performed the first network node 110 when being located within the radio coverage area or cell 136 for the one or more of the conventional frequency bands of the second

10 network node 1 11 indicated by the dotted area in Fig. 2. In some embodiments, the first network node 110 may detect the presence of a second network node 11 1 in the wireless communications network 100 by receiving one or more periodic beacon frames or management frames comprising information indicating the presence of the second network node 11 1 from the second network node 1 11 on said one or more frequency

15 bands within the first radio coverage area 136. Optionally, in some embodiments, the first network node 110 may detect the presence of a second network node 1 11 in the wireless communications network 100 by receiving one or more preambles or data payloads comprising information indicating the presence of the second network node 11 1 in the wireless communications network 100 in a transmission from the second network node

20 1 11 on said one or more frequency bands within the first radio coverage area 136.

Alternatively, the first network node 110 may furthermore detect the presence of a second network node 1 11 in the wireless communications network 100 by receiving one or more preambles or data payloads comprising information indicating the presence of the second network node 1 11 in the wireless communications network 100 in a transmission from the

25 second network node 1 11 on said one or more frequency sub-bands within the second radio coverage area 136'. In this case, the first network node 110 may be located outside the radio coverage area or cell 136 for the one or more of the conventional frequency bands of the second network node 1 11 in the example scenario shown in Fig. 2. However, in this case, the first network node 110 must still be located within the radio coverage area

30 or cell 136' for the one or more of the frequency sub-bands of the second network node 1 11 in the example scenario shown in Fig. 2.

According to one example, the first network node 11 1 may receive a transmission from the second network node 11 1 with a legacy preamble, which may be decoded by the first network node 11 1 , whereby in case this legacy preamble is followed by a frequency

35 sub-band, or narrowband, payload may indicate to the first network node 11 1 that the second network node 1 11 is simultaneously transmitting on one or more frequency sub- bands. Optionally, the first network node 1 10 may identify or detect that the second network node 1 11 is simultaneously transmitting on one or more frequency sub-bands by decoding the content of the preamble, which, for example, may have a special pattern or 5 comprise a dedicated data field indicating that the second network node 11 1 is

simultaneously transmitting on one or more frequency sub-bands.

It should be noted that terms "radio coverage area" or "cell" herein refers to an area within which transmissions from one network node may be received and decoded correctly by another network node.

10

Also, in some embodiments, the information indicating the presence of the second network node 11 1 may comprise one or more of: an indication of the type of the second network node 1 11 , an indication of the identity of the second network node 1 11 ; an indication of the one or more frequency sub-bands on which the second network node

15 1 11 operates; an indication of the load of the second network node 11 1 , and an indication of transmission characteristics of the second network node 1 11. Here, the indication of the type of the second network node 11 1 may, for example, be information indicating that the second network node 11 1 is a network node that is separately operating on said one or more frequency bands within a first radio coverage area 136 and on one or more

20 frequency sub-bands within a second radio coverage area 136, e.g. that the second

network node 1 11 is an LRLP AP. The indication of the identity of the second network node 11 1 may, for example, be an SSID or a MAC address of the second network node 11 1.The indication of the load of the second network node 11 1 may, for example, be information indicating the number of associated STAs that is currently being served by the

25 second network node 11 1 , i.e. the number of LRLP STAs, and channel utilization of the second network node 11 1 and its associated STAs, i.e. the channel utilization of LRLP BSS. The indication of transmission characteristics of the second network node 1 11 may, for example, be information indicating whether or not the second network node 1 11 use frequency hopping or OFDMA.

30 Furthermore, in some embodiments, the information indicating the presence of the second network node 11 1 may be a simple indicator for the existence of the second network node 1 11 , i.e. any overlapping LRLP BSS. The indicator may comprise one bit for which "1" indicates that the second network node 1 11 is simultaneously transmitting on one or more frequency sub-bands, e.g. indicates the existence of an overlapping LRLP

35 BSS, and for which "0" indicates that the second network node 11 1 is not simultaneously transmitting on one or more frequency sub-bands, e.g. indicates the non-existence of any overlapping LRLP BSS.

Action 303

After the detection in Action 302, the first network node 1 10 transmits information to at least one third network node 112 in the wireless communications network 100 indicating the presence of the second network node 1 11. In this way, the first network node 110 may make the third network node 112 aware of the presence of the second network node 1 11 in the wireless communications network 100. Thus, the third network node 112 is able to use this information for various purposes, such as, e.g. channel selection. The first network node 1 10 may, for example, transmit the information using a broadcast, multicast or unicast transmission. Here, it should be noted that the information indicating the presence of the second network node 11 1 may be the type of indications as described above in Action 302.

In other words, when the first network node 1 10 detects an overlapping LRLP

BSS, such as, e.g. the second network node 1 12 and the STA 121 ' in the example scenario of Fig. 2, the first network node 110 may construct a message comprising the knowledge of the detected LRLP BSS and transmit this knowledge to other legacy devices, such as, e.g. the third network node 112 in the example scenario of Fig. 2, in the wireless communications network 100. The message may, for example, be broadcasted by the first network node 1 10 such that all legacy devices, such as, e.g. the third network node 112 in the example scenario of Fig. 2, that are able to receive and decode the broadcasted message will be made aware of the existence of the LRLP BSS. Hence, the legacy devices are enabled to use this knowledge for improving its network node operation.

In some embodiments, this may be performed by transmitting one or more periodic beacon frames or management frames comprising information indicating the presence of the second network node 1 11 to the at least one third network node 1 12 on said one or more frequency bands within a third radio coverage area 135. This means that the first network node 1 10 may insert the information into a beacon frame which is broadcasted periodically. This also means that the first network node 110 may insert the information into a management frame. This management frame may be transmitted or broadcasted periodically. However, alternatively, this management frame may also be requested by other legacy APs, such as, the third network node 112 in the example scenario in Fig. 2, and transmitted upon the request as indicated in Action 301. According to a further option, the management frame may further be transmitted only when certain conditions are fulfilled in the first network node 1 10. One example of such a condition may be that a second network node 110, e.g. an overlapping LRLP BSS, has been detected and that the load of the second network node 1 11 , e.g. the load of the LRLP BSS, is above a determined threshold. Optionally, according to some embodiments, this may be performed by transmitting one or more preambles or data payloads comprising information indicating the presence of the second network node 11 1 to the at least one third network node 1 12 on said one or more frequency bands within a third radio coverage area 135. For example, a new information element, IE, for carrying the information indicating the presence of the second network node 11 1 to the at least one third network node 112 may be introduced in a BSS load report between network nodes, such as, e.g. the current BSS load report between APs according to the IEEE 802.11 standard.

Alternatively, in some embodiments, in response to detecting the presence of the at least one third network node 112 or receiving a request for information from the at least one third network node 112 as described in Action 301 , the first network node 1 10 may further perform the transmission in case both the second network node 1 11 and the at least one third network node 1 12 have been detected. In other words, the first network node 110 may perform the transmission only when both a LRLP BSS and a legacy BSS are detected in within its neighbourhood.

In some embodiments, the first network node 1 10 may further estimate the second radio coverage area 136' for said one or more frequency sub-bands of the second network node 11 1 based on the received signal strength of transmissions received from the second network node 11 1 on said one or more frequency sub-bands. The received signal strength may e.g. be a received signal strength indicator, a measured signal strength indicator, a received Signal-to-Noise ratio, SINR, indicator, etc. After the estimation, the first network node 1 10 may further determine if the at least one third network node 112 is present within the estimated second radio coverage area 136'. In response to said determination, the first network node 110 may perform the transmission if the at least one third network node 112 is determined to be present within the estimated second radio coverage area 136'. In other words, the first network node 110 may estimate the range or distance of the LRLP AP with respect to the third network node 1 12 based on the received signal strength of the transmission from the LRLP AP. The first network node 1 10 may then perform the transmission only when the third network node 1 12 is within the range or distance of the LRLP AP. Example of embodiments of a method performed by a third network node 1 12 for operating on one or more frequency bands in a wireless communications network 100 will now be described with reference to the flowchart depicted in Fig. 4. Fig. 4 illustrates an example of actions or operations which may be taken by the third network node 1 12 as shown in Fig. 6. The method may comprise the following actions.

Action 401

Optionally, the third network node 1 12 may first transmit information to the first network node 110 requesting information indicating if a second network node 11 1 has been detected by the first network node 110 in the wireless communications network 100. Thus, the third network node 1 12 may make the first network node 1 10 aware that the third network node 1 12 desires this information and is capable of using said information to improve its network node operation. The transmission may, for example, be broadcast, multicast or unicast transmission.

Action 402

The third network node 1 12 receives, from a first network node 1 10, information indicating the presence of a second network node 11 1 in the wireless communications network 100, wherein the second network node 11 1 separately operates on said one or more frequency bands within a first radio coverage area 136 and on one or more frequency sub-bands within a second radio coverage area 136', wherein said one or more frequency sub-bands are smaller than and forms a part of any of said one or more frequency bands. Here, it should be noted that the information indicating the presence of the second network node 1 11 may be any of the type of indications as described above in Actions 302-303. The third network node 1 12 may, for example, receive the information in a broadcast, multicast or unicast transmission from the first network node 1 11 comprised in a beacon frame, a management frame, preambles and/or data payloads.

For example, in some embodiments, the third network node 112 may sweep across frequency bands passively to detect beacons, receive beacon frames, collect spectrum usage information and, which is described in more detail below in Action 403, decide which frequency band to operate on based on the sweeping results.

Action 403 After receiving the information in Action 402, the third network node 1 12 adapts transmissions from the third network node 1 12 on said one or more frequency bands based on said received information. This means that the third network node 112 may use the received information in order to optimize its transmissions to the STAs its currently serving, such as, e.g. the STA 121 in the example scenario of Fig. 2.

For example, the third network node 112 may use the received information in its channel selection algorithms. In some embodiments, this may be performed by selecting, based on said received information, one frequency band from said one or more frequency bands to be used for transmissions from the third network node 1 12. For example, the channel selection algorithm of the third network node 1 12 may select the least congested channel or frequency band for operating in. This means that the third network node 1 12 may perform a smarter channel allocation and thus more effectively minimize interference between transmissions on the one or more conventional frequency bands and

transmission on the one or more frequency sub-bands, such as, e.g. between LRLP transmissions and legacy WLAN transmissions. It may also added that minimizing interference between network nodes in the BSSs will also improve the operational efficiency and capacity of the network nodes in the BSSs.

In some embodiments, when the received information comprise an indication of the transmission characteristics of the transmissions on the one or more frequency sub- bands of the second network node 1 11 , such as, e.g. whether or not frequency hopping or OFDMA is used, the third network node 112 may use this knowledge to adapt its own transmissions in order to mitigate interference with the transmissions of the second network node 1 11. In other words, the carrier frequency of the one or more frequency sub-bands of the second network node 1 11 overlaps with one or a few Resource Units, RUs, of the one or more conventional frequency bands used for transmissions by the first and third network nodes 110, 112. The transmission characteristics of the transmissions on the one or more frequency sub-bands of the second network node 1 11 may be the specific RUs used for the transmission when the RU allocation of the transmission is relatively static. However, if frequency hopping is applied for the transmission by the second network node 11 1 , the transmission characteristics of the transmissions on the one or more frequency sub-bands of the second network node 11 1 may be the hopping pattern identified by the first network node 1 10. Thereby, the third network node 112 may use this knowledge to mitigate interference with the transmissions on the one or more frequency sub-bands of the second network node 1 11. For example, by applying OFDMA transmission, the third network node 112 may avoid allocating the overlapping RUs for its own transmissions on the one or more conventional frequency bands to and/or from its associated STAs.

Action 404

Following the adaptation in Action 403, the third network node 112 may transmit information indicating the presence of the second network node 1 11 in the wireless communications network 100 to a further network node (not shown) in the wireless communications network 100. In this case, the information may comprises an indication that the information has been forwarded by the third network node 1 12 from the first network node 110. The indication that the information is being relayed by the third network node 112 may, for example, comprise a hop count, i.e. which hop count may be incremented by "1" for each relay between network nodes.

To perform the method actions for enabling at least one third network node 1 12 to operate on one or more frequency bands in a wireless communications network 100, the first network node 110 may comprise the following arrangement depicted in Fig. 5. Fig. 12 shows a schematic block diagram of embodiments of the first network node 110. The embodiments of first network node 110 described herein may be considered as independent embodiments or may be considered in any combination with each other to describe non-limiting examples of the example embodiments described herein.

The first network node 110 may comprise a processing circuitry 510, a memory 520 and at least one antenna (not shown). The first network node 110 may also comprise a receiving module 511 and a transmitting module 512. The receiving module 511 and the transmitting module 512 may comprise Radio Frequency, RF, circuitry and baseband processing circuitry. The receiving module 51 1 and the transmitting module 512 may also be co-located, such as, in a transceiver, and may also be said to form part of the processing circuitry 510. In some embodiments, some or all of the functionality described above as being performed by the first network node 110 may be provided by the processing circuitry 510 executing instructions stored on a computer-readable medium, such as, e.g. the memory 520 shown in Fig. 5. Alternative embodiments of the first network node 1 10 may comprise additional components, such as, a detecting module 513, estimating module 514 and determining module 515, each responsible for providing its functionality necessary to support the embodiments described herein. The first network node 110 or processing circuitry 510 is configured to, or may comprise the detecting module 513 configured to, detect the presence of a second network node 1 11 in the wireless communications network 100, wherein the second network node 1 11 separately operates on said one or more frequency bands within a first radio coverage area 136 and on one or more frequency sub-bands within a second radio coverage area 136', wherein said one or more frequency sub-bands are smaller than and forms a part of any of said one or more frequency bands. Also, the AP 110 or processing circuitry 510 is configured to, or may comprise the transmitting module 512 configured to, transmit information to at least one third network node 112 in the wireless

communications network 100 indicating the presence of the second network node 11 1.

In some embodiments, the first network node 1 10 or processing circuitry 510 may be configured to, or may comprise the receiving module 511 configured to, receive one or more periodic beacon frames or management frames comprising information indicating the presence of the second network node 11 1 from the second network node 1 11 on said one or more frequency bands within the first radio coverage area 136. Alternatively, according to some embodiments, the first network node 1 10 or processing circuitry 510 may be configured to, or may comprise the receiving module 51 1 configured to, receive one or more preambles or data payloads comprising information indicating the presence of the second network node 11 1 in the wireless communications network 100 in a transmission from the second network node 1 11 on said one or more frequency bands within the first radio coverage area 136, or on said frequency sub-band within the second radio coverage area 136'.

In some embodiments, the first network node 110 or processing circuitry 510 may be configured to, or may comprise the transmitting module 511 configured to, transmit one or more periodic beacon frames or management frames comprising information indicating the presence of the second network node 11 1 to the at least one third network node 1 12 on said one or more frequency bands within a third radio coverage area 135. Alternatively, in some embodiments, the first network node 1 10 or processing circuitry 510 may be configured to, or may comprise the transmitting module 51 1 configured to, transmit one or more preambles or data payloads comprising information indicating the presence of the second network node 1 11 to the at least one third network node 1 12 on said one or more frequency bands within a third radio coverage area 135.

In some embodiments, the information indicating the presence of the second network node 1 11 in the wireless communications network 100 comprise one or more of: an indication of the type of the second network node 111 , an indication of the identity of the second network node 1 11 , an indication of the one or more frequency sub-bands on which the second network node 1 11 operates, an indication of the load of the second network node 11 1 , and an indication of transmission characteristics of the second network node 11 1.

In some embodiments, the first network node 1 10 or processing circuitry 510 may be configured to, or may comprise the detecting module 513 configured to, detect the presence of the at least one third network node 112, and perform the transmission of the information to at least one third network node 112 in case both the second network node 1 11 and the at least one third network node 1 12 have been detected.

In some embodiments, the first network node 1 10 or processing circuitry 510 may be configured to, or may comprise the estimating module 514 configured to, estimate the second radio coverage area 136' for said one or more frequency sub-bands of the second network node 11 1 based on the received signal strength of transmissions received from the second network node 11 1 on said one or more frequency sub-bands. In this case, the first network node 1 10 or processing circuitry 510 may also be configured to, or may comprise the determining module 515 configured to, determine if the at least one third network node 112 is present within the estimated second radio coverage area 136'.

Furthermore, in this case, the first network node 110 or processing circuitry 510 may further be configured to, or may comprise the transmitting module 512 configured to, perform the transmission of the information to the at least on third network node 1 12 if the at least one third network node 1 12 is determined to be present within the estimated second radio coverage area 136'.

In some embodiments, the first network node 1 10 or processing circuitry 510 may be configured to, or may comprise the receiving module 511 configured to, receive information from the at least one third network node 112 requesting information indicating if a second network node 1 11 has been detected by the first network node 110 in the wireless communications network 100.

Furthermore, the embodiments of the first network node 1 10 for enabling at least one third network node 1 12 to operate on one or more frequency bands in the wireless communications network 100 described above may be implemented through one or more processors, such as, the processing circuitry 510 in the first network node 110 depicted in Fig. 5, together with computer program code for performing the functions and actions of the embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier, such as, e.g. an electronic signal, optical signal, radio signal, or computer-readable storage medium, carrying computer program code or code means for performing the embodiments herein when being loaded into the processing circuitry 510 in the first network node 110. The computer program code may e.g. be provided as pure program code in the first network node 110 or on a server and downloaded to the first network node 110.

Those skilled in the art will also appreciate that the processing circuitry 510 and the memory 520 described above may refer to a combination of analog and digital circuits, and/or one or more processors configured with software and/or firmware, e.g. stored in a memory, that when executed by the one or more processors such as the processing circuitry 520 perform as described above. One or more of these processors, as well as the other digital hardware, may be included in a single application-specific integrated circuit (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a system- on-a-chip (SoC).

It should be noted that the modules of the first network node 110 may in some embodiments be implemented as computer programs stored in memories, e.g. in the memory module 520 in Fig. 5, for execution by processors, e.g. the processing module 510 of Fig. 5.

To perform the method actions for operating on one or more frequency bands in a wireless communications network 100, the third network node 1 12 may comprise the following arrangement depicted in Fig. 6. Fig. 6 shows a schematic block diagram of embodiments of the third network node 1 12. The embodiments of third network node 1 12 described herein may be considered as independent embodiments or may be considered in any combination with each other to describe non-limiting examples of the example embodiments described herein.

The third network node 1 12 may comprise a processing circuitry 610, a memory 620 and at least one antenna (not shown). The third network node 112 may also comprise a receiving module 611 and a transmitting module 612. The receiving module 611 and the transmitting module 612 may comprise Radio Frequency, RF, circuitry and baseband processing circuitry. The receiving module 61 1 and the transmitting module 612 may also be co-located, such as, in a transceiver, and may also be said to form part of the processing circuitry 610. In some embodiments, some or all of the functionality described above as being performed by the third network node 1 12 may be provided by the processing circuitry 610 executing instructions stored on a computer-readable medium, such as, e.g. the memory 620 shown in Fig. 6. Alternative embodiments of the third network node 112 may comprise additional components, such as, the adapting module 613, responsible for providing its functionality necessary to support the embodiments described herein.

The third network node 1 12 or processing circuitry 610 is configured to, or may comprise the receiving module 61 1 configured to, receive, from a first network node 110, information indicating the presence of a second network node 11 1 in the wireless communications network 100, wherein the second network node 1 11 separately operates on said one or more frequency bands within a first radio coverage area 136 and on one or more frequency sub-bands within a second radio coverage area 136', wherein said one or more frequency sub-bands are smaller than and forms a part of any of said one or more frequency bands. Also, the third network node 1 12 or processing circuitry 610 is configured to, or may comprise the adapting module 613 configured to, adapt

transmissions from the third network node 1 12 on said one or more frequency bands based on said received information.

In some embodiments, the third network node 1 12 or processing circuitry 610 may be configured to, or may comprise the adapting module 613 configured to, select, based on said received information, one frequency band from said one or more frequency bands to be used for transmissions from the third network node 112.

Optionally, the third network node 112 or processing circuitry 610 may be configured to, or may comprise the receiving module 611 configured to, transmit information to the first network node 1 10 requesting information indicating if a second network node 11 1 has been detected by the first network node 110 in the wireless communications network 100.

In some embodiments, the third network node 1 12 or processing circuitry 610 may be configured to, or may comprise the transmitting module 612 configured to, transmit information indicating the presence of the second network node 11 1 in the wireless communications network 100 to a further network node in the wireless communications network 100, wherein said information comprises an indication that the information has been forwarded by the third network node 1 12 from the first network node 110.

Furthermore, the embodiments of the third network node 112 for operating on one or more frequency bands in a wireless communications network 100 described above may be implemented through one or more processors, such as, the processing circuitry 610 in the third network node 1 12 depicted in Fig. 6, together with computer program code for performing the functions and actions of the embodiments herein. The program code mentioned above may also be provided as a computer program product, for instance in the form of a data carrier, such as, e.g. an electronic signal, optical signal, radio signal, or computer-readable storage medium, carrying computer program code or code means for performing the embodiments herein when being loaded into the processing circuitry 610 in the third network node 1 12. The computer program code may e.g. be provided as pure program code in the third network node 1 12 or on a server and downloaded to the third network node 1 12.

Those skilled in the art will also appreciate that the processing circuitry 610 and the memory 620 described above may refer to a combination of analog and digital circuits, and/or one or more processors configured with software and/or firmware, e.g. stored in a memory, that when executed by the one or more processors such as the processing circuitry 620 perform as described above. One or more of these processors, as well as the other digital hardware, may be included in a single application-specific integrated circuit (ASIC), or several processors and various digital hardware may be distributed among several separate components, whether individually packaged or assembled into a system- on-a-chip (SoC).

It should be noted that the modules of the third network node 112 may in some embodiments be implemented as computer programs stored in memories, e.g. in the memory module 620 in Fig. 6, for execution by processors, e.g. the processing modules 610 of Fig. 6.

The terminology used in the detailed description of the particular embodiments illustrated in the accompanying drawings is not intended to be limiting of the described AP 110, STA 121 and methods therein which instead should be construed in view of the enclosed claims.

As used herein, the term "and/or" comprises any and all combinations of one or more of the associated listed items.

Further, as used herein, the common abbreviation "e.g.", which derives from the

Latin phrase "exempli gratia," may be used to introduce or specify a general example or examples of a previously mentioned item, and is not intended to be limiting of such item. If used herein, the common abbreviation "i.e.", which derives from the Latin phrase "id est," may be used to specify a particular item from a more general recitation. The common abbreviation "etc.", which derives from the Latin expression "et cetera" meaning "and other things" or "and so on" may have been used herein to indicate that further features, similar to the ones that have just been enumerated, exist.

As used herein, the singular forms "a", "an" and "the" are intended to comprise also the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms "includes," "comprises," "including" and/or "comprising," when used in this specification, specify the presence of stated features, actions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, actions, integers, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined, all terms comprising technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the described embodiments belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

The embodiments herein are not limited to the above described preferred embodiments. Various alternatives, modifications and equivalents may be used.

Therefore, the above embodiments should not be construed as limiting.

Abbreviations

AP Access Point

STA Station

OBSS Overlapping Basic Service Sets

BSS Basic Serving Set

WLAN Wireless Local Area Network

OFDMA Orthogonal Frequency-Division Multiple Access

IE Information Element

LRLP Long Range Low Power

M2M Machine-to-Machine

loT Internet of Things