Unified wake up signal

Abstract

According to some embodiments, a wireless device receives, from a network node, a wake up signal, WUS, comprising an on-off keyed, OOK, pattern where orthogonal frequency division multiplexing, OFDM, sequences are transmitted during ON durations of the OOK pattern. First information is 5 carried by the OOK pattern and second information is carried by the OFDM sequences. The second information includes additional information not included in the first information. According to some embodiments, a wireless device receives, from a network node, a synchronization signal comprising an OOK pattern where OFDM sequences are transmitted during ON durations of the OOK pattern. Information is carried by the OFDM sequences in the synchronization signal. The 0 wireless device uses at least part of the synchronization signal as a synchronization signal for a wake up receiver, WUR.

Description

UNIFIED WAKE UP SIGNALTECHNICAL FIELDThe present disclose generally relates to wireless communication, and more particularly to transmission and reception of a wake-up signal (WUS).BACKGROUNDA wake-up receiver (WUR), sometimes also referred to as “wake-up radio,” enables a low power receiver in a user equipment (UE), upon detection of a wake-up signal (WUS), to wake up the main (baseband / radio frequency (RF) / less power efficient) receiver to detect an incoming message, typically paging (e.g., physical downlink control channel (PDCCH) in paging occasions (POs), scheduling the paging message on physical downlink shared channel (PDSCH)). A benefit of employing a WUR is lower energy consumption and longer device battery life, or at a fixed energy consumption the downlink latency may be reduced (shorter discontinuous reception (DRX) / duty-cycles and more frequent checks for incoming transmissions).Figure 1 is timing diagram illustrating the location of a WUS and the paging occasion to which it is associated.In general, there are two approaches for detecting a WUS. A first approach uses the main receiver. In this approach, there is no need for additional dedicated hard ware / recei ver for monitoring WUS, coverage of the main receiver is not typically impacted, and limited power saving gain is obtained because the main receiver monitors WUS.A second approach uses a dedicated receiver (WUR). This approach may be extremely low power, may use a simple and low-cost receiver architecture, may follow relaxed requirements, and may use a noisier (i.e., less accurate) clock or oscillator. This approach includes significant power saving gain by maximizing the time in which the main receiver can be in the sleep mode. This approach enables zero energy / battery-less devices, and energy harvesting operations. There are coverage considerations given the tradeoff between WUR power consumption and sensitivity.As an example, Figure 2 illustrates a dedicated wake up receiver (WUR) used for monitoring a wake-up signal (WUS). Once the WUR detects the intended WUS, it wakes up the main (baseband / RF / less power efficient) receiver to detect further incoming messages. Therefore, the main receiver can go to sleep mode and save power until it is triggered by the WUR. Here, the WUR is an ultra-low power and low-complexity receiver which can support simple modulation schemes such as on-off keying (OOK), frequency-shift keying (FSK), or phase-shift keying(PSK). However, the WUS is transmitted using an orthogonal frequency division multiplexing (OFDM)-based transmitter.The Third Generation Partnership Project (3GPP) Release 15 (Rel-15) specified WUS for narrowband Intemet-of-tings (NB-IoT) and LTE for machine type communication (LTE-M). The main motivation was UE energy consumption reduction because with the coverage enhancement PDCCH could be repeated many times and the WUS is relatively much shorter and thus requires less reception time for the UE. The logic is that a UE checks for a WUS a certain time before its paging occasion (PO), and only if a WUS is detected the UE would continue to check for PDCCH in the PO, and if not, which is most of the time, the UE can go back to a sleep state to conserve energy. Due to the coverage enhancements the WUS can be of variable length depending on the UE’s coverage, see Figure 3.In Rel-15, a WUS is based on the transmission of a short signal that indicates to the UE that it should continue to decode the downlink control channel, e.g. full NPDCCH for NB-IoT. If such signal is absent (DTX i.e. UE does not detect it) then the UE can go back to sleep without decoding the downlink control channel. The decoding time for a WUS is considerably shorter than that for the full NPDCCH because it essentially only needs to contain one bit of information whereas the NPDCCH may contain up to 35 bits of information. This, in turn, reduces UE power consumption and leads to longer UE battery life. The WUS is transmitted only when there is a paging for the UE. If there is no paging for the UE, then the WUS will not be transmitted (i.e., implying a discontinuous transmission, DTX) and the UE goes back to deep sleep, e.g. upon detecting DTX instead of WUS. This is illustrated in Figure 1 where blocks with thin edges indicate possible WUS and PO positions whereas blocks with thick edges (i.e. the middle blocks) indicate actual WUS and PO positions.The specification of Rel-15 WUS is spread out over several parts of the LTE 36-series standard, e.g., 36.211, 36.213, 36.304 and 36.331.In the Rel-16, it was agreed that WUS should be further developed to also include UE grouping, such that the number of UEs that are triggered by a WUS is further narrowed down to a smaller subset of the UEs that are associated with a specific paging occasion (PO). The purpose of UE grouping is to reduce the false paging rate, i.e. avoid that a given UE is unnecessarily woken up by a WUS transmission intended for another UE. This feature is referred to as Rel-16 group WUS, or GWUS. However, this is not directly related to WUR and will not further be explained hereafter.In Rel-17, discussions started on introducing a WUS for NR, then called ‘Paging Early Indication’ (PEI). However, because at the time no coverage enhancement was specified for NR, the only gain for Rel-17 PEI was for scenarios where the small fraction of UEs are in bad coverage and with large synchronization error due to the use of longer DRX cycles. The gain for such UEs was that with the use of PEI they would typically only have to acquire one SSB before decoding PEI, instead of up to 3 SSBs if PEI is not used (value according to UE vendors). So, for most UEs, Rel-17 PEI will result in gains or increased performance.Rel-17 PEI will also support UE grouping for false paging reduction, similar to the Rel-16 GWUS above, which will have some gains at higher paging load.But it was decided that PEI will be PDCCH-based, making it much less interesting for WUR (i.e., the main baseband receiver is required for decoding PEI).In Rel-18, there has been rather large interest to introduce WUR for NR, with an ambition for achieving more significant energy efficiency improvement compared to solutions already specified in earlier releases. As explained above, the only specification support needed to be able to use a WUR in the UE is the specification of a WUS and a long enough time gap between the WUS and the PDCCH in the PO (to allow the UE to start up the main receiver). Therefore, the main difference to Rel-17 PEI is that the WUS in Rel-18 should not be PDCCH-based and allow for a simpler and low power receiver, i.e. a WUR with simple modulation and detection techniques (e.g., using on-off keying (OOK) modulation and non-coherent detection).In Rel-18, a study item on “low-power wake-up signal and receiver for NR” was approved.A benefit of WUR is to reduce the energy consumption of the receiver, such that unless there is any paging and data for the UE it can remain in a power saving state. This will extend the battery life of the device, or alternatively enable shorter downlink latency (shorter DRX) at a fixed battery life. For short-range communication, the WUR power can be low enough (~10 uW) that this can even, in combination with energy harvesting, enable that the WUR is continuously on (i.e. DRX or duty-cycling is not used) without the need for a battery. This can be considered as a key enabler of battery -less devices towards 6G.The Rel-18 study item on “low-power wake-up signal and receiver for NR” has been completed and the technical report is provided in, 3GPP TR 38.869 VO.4.0, “Study on low-power Wake-up Signal and Receiver for NR”. According to the outcome of this study, one important aspect of designing WUR / WUS is synchronization using a low power sync signal (LP-SS) as highlighted in the text below from 3GPP TR 38.869 VO.4.0.At least for LP-WUR that cannot receive existing PSS / SSS, periodic LP-SS signal is beneficial for the following functionalities: (a) RRM measurements by LP-WUR, if supported (b) At least coarse time synchronization of LP-WUR. (c) At least coarse frequency synchronization of LP-WUR. Additional periodic LP-SS system overhead depends on LP-SS periodicity, system bandwidth, number of beams, and resource required to fulfill the target functionality, etc. Periodic signal if used for coarse synchronization may reduce the overhead of signal preceding LP-WUS, if any. LP-SS can be designed to be common among UE groups (cell-specific) and further reduce system overhead. For LP-WUR that can receive existing PSS / SSS potentially assisted by PBCH DMRS / TRS for synchronization, existing PSS / SSS potentially assisted by PBCH DMRS / TRS may be used for above functionality. Periodic LP-SS coverage should be equal or better than that of LP-WUS. For fine time and frequency synchronization, a signal (e.g., preamble) preceding or part of LP-WUS may be used. OFDMA waveform can provide coverage for LP-WUS with lower resource overhead. LP-WUR receiving OFDMA waveform can reuse PSS / SSS to perform RRM measurement and synchronization avoiding the introduction of periodic LP-SS within the carrier. Timing error robustness can be further improved using a sliding window at the receiver.IEEE 802.11 standardized the support for WUR in the task group (TG) ba. Similar to the 3GPP solution, the use of WUR is only enabled in stations and not in access points (APs), that is for downlink communication only. The AP advertises that it has WUR operation capability, along with WUR configuration parameters (among other info, in which band / channel WUR is operational, which can be different from the band / channel used for data transmission using the main receiver, e.g. WUR in 2.4 GHz band but data communication in 5 GHz band. Also note that the WUR operating channel is advertised in the beacon, and that the WUR discovery operating channel may be different from the WUR operating channel.). Stations can then request to be configured with WUR mode of operation. This request has to be granted by the AP, and when it is granted, the station is further configured / setup for WUR mode of operation (the configuration is only valid for the connection to the associated AP, and further the configuration must be tom down / de-configured if WUR is not used anymore). Both continuous WUR (receiver open all the time) and duty-cycled WUR (receiver only open during preconfigured time slots) mode of operations are supported. For the latter the length of the duty-cycles and on-time during wake up is part of the WUR configuration.Unlike the 3GPP solution, the WUR operation mode is a “sub-state” of the regular operation and upon the detection of a WUS transmission from the AP, the station will resume the power saving mechanism it was configured with before entering the WUR operation mode. That is, IEEEhas specified a number of different power saving mechanisms, and for example if duty-cycled monitoring of the downlink has been configured for the station it will switch to that upon detection of the WUS (i.e. unlike the specified 3GPP mechanism which only covers paging, and the UE will continue to monitor PDCCH if WUS is detected). In this way the IEEE WUR functionality is more general, and still allows for the station to upon detection of WUS “monitor paging” by checking in the beacon from the AP for which stations there is data, or for the station to directly respond with an uplink transmission.The physical wake-up signal (WUS) in IEEE contains complete frames which must be processed by the station. The drawback with this design is that it requires more handling and processing in the station, i.e. compared to a simple WUR design which trigger one pre-defined activity in case WUS is detected. The benefit is that it contains more information and the solution is more general. The IEEE WUS contains information to indicate if the WUS is a WUR sync beacon, a WUR discovery beacon, or a regular WUS (intended to wake the station up). The WUS can also contain proprietary frames, which could e.g. be used to directly turn actuators on / off. The transmission uses on / off keying (OOK) modulation, using Manchester coding, but is using multicarrier OOK which can be generated by an OFDM transmitter (i.e. WUR can be enabled as a software upgrade in APs). The WUS is 4 MHz wide, but a whole 20 MHz channel is reserved. The WUS starts with a 20 MHz legacy preamble (to allows other stations to perform carrier sense) followed by 4 MHz Manchester coded OOK. Two data rates are supported: 62.5 kbps and 250 kbps, and link adaptation is up to the AP (each packet is self-contained and includes the data rate, i.e. in the WUR there are two possible sync words used to signal the data rate).There currently exist certain challenges. For example, power saving methods enabled by low-powered (LP)-wake up signal (WUS) / wake up receiver (WUR) have been studied in 3GPP Rel-18. Several candidates for the low-powered wake-up signals and receiver architectures were considered. In practice, supporting many possible combinations low-powered wake-up signals and receiver architectures in the system will increase system complexity significantly and thus should be avoided. A unified WUS design which can be received by multiple types of WUR architectures and / or capabilities is proposed as one possible solution. But it is unclear what information should be considered to be included in the WUS payload and how it provided in such a unified WUS design.SUMMARYA first aspect provides embodiments of a method performed by a wireless device. The method comprises receiving, from a network node, a wake up signal (WUS) comprising an on-off keyed (OOK) pattern where orthogonal frequency division multiplexing (OFDM) sequences are transmitted during ON durations of the OOK pattern. First information is carried by the OOK pattern and second information is carried by the OFDM sequences. The second information includes additional information not included in the first information.Corresponding embodiments of a wireless device are also provided.A second aspect provides embodiments of a method performed by a network node. The method comprises transmitting a WUS comprising an OOK pattern where OFDM sequences are transmitted during ON durations of the OOK pattern. First information is carried by the OOK pattern and second information is carried by the OFDM sequences. The second information includes additional information not included in the first information.Corresponding embodiments of a network node are also provided.A third aspect provides embodiments of a method performed by a wireless device. The method comprises receiving, from a network node, a synchronization signal comprising an OOK pattern where OFDM sequences are transmitted during ON durations of the OOK pattern. Information is carried by the OFDM sequences. The method further comprises using at least part of the synchronization signal as a synchronization signal for a wake up receiver (WUR).Corresponding embodiments of a wireless device are also provided.BRIEF DESCRIPTION OF THE DRAWINGSExample embodiments will be described below with reference to the accompanying drawings, on which:Figure 2 is timing diagram illustrating the location of a WUS and the paging occasion to which it is associated;Figure 2 illustrates a WUR accompanying a main receiver:Figure 3 illustrates WUS for NB-IoT and LTE-M;Figure 4 illustrates a network node transmitting a sync signal to a low-power receiver;Figure 5 illustrates a unified WUS based on an OOK waveform where some specific OFDMbased sequences are used during the ON duration of the OOK pattern;Figure 6 illustrates an example of a WUS structure comprising WUS1 and WUS2;Figure 7 illustrates different content of OOK-based WUS and OFDM-based WUS;Figure 8 shows a flow chart of a method performed by a wireless device according to some embodiments.Figure 9 shows a flow chart of a method performed by a network node according to some embodiments.Figure 10 shows a flow chart of a method performed by a wireless device according to some embodiments.Figure 11 shows a flow chart of a method performed by a network node according to some embodiments.Figure 12 illustrates a communication system which enables connectivity between UEs, network nodes, and a host;Figure 13 illustrates a UE according to some embodiments;Figure 14 illustrates a network node according to some embodiments;Figure 15 illustrates a host according to some embodiments;Figure 16 is a block diagram illustrating a virtualization environment in which functions implemented by some embodiments may be virtualized; andFigure 17 shows a communication diagram of a host communicating via a network node with a UE over a partially wireless connection in accordance with some embodiments.DETAILED DESCRIPTIONCertain aspects of the disclosure and their embodiments may provide solutions to the challenges mentioned above in the background section. For example, some embodiments include a unified WUS design comprising an OOK waveform / pattem of which certain OFDM sequence(s) are used for transmission during the ON durations. Some embodiments include carrying WUS information in the OFDM signal part of the unified WUS structure. For example, some embodiments have additional information carried in the OFDM signal part of the WUS compared to the information carried in the OOK pattern of the WUS.Moreover, a similar design of unified WUS may be used for a new specific low power synchronization signal (LP-SS) for WUR operation. In such case, additional information carried in the unified LP-SS is described.In general, some embodiments include: (a) additional WUS information carried in the OFDM part of the unified WUS; (b) WUS information structure where WUSOOK is common information modulated in OOK and OFDM parts of the WUS, and WUSadditionai is additional information in the OFDM part of the WUS, i.e., WUS OOK is carried in the OOK pattern andWUSooK+WUSadditonai is carried in the OFDM signal; (c) different purposes of additional (OFDM) WUS information; and (d) additional information carried in the unified LP-SS structure.Certain embodiments may provide one or more of the following technical advantages. For example, some embodiments include a unified WUS structure to support WUS information that provides additional benefit and functionalities to WUR operation, especially to a WUR capable of receiving an OFDM-based signal.Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.A low power receiver such as a wake-up receiver (WUR) is expected to have limited capabilities in terms of supported modulation schemes, synchronization, and receiver architecture. For example, the WUR may only support a simple modulation scheme such as on-off keying (OOK) and employ time domain envelope detection. Nevertheless, in some other cases, a low power wake-up receiver may be more capable, e.g., capable of receiving an OFDM-based signal or both OOK-based and OFDM-based signals. For deployment flexibility, and ease of network implementation, it may be beneficial that the WUS design accommodates both types of WUR.Different use cases may have different service requirements, e.g., in terms of coverage for WUS reception and mobility support of WUR operation. For example, in use cases with less stringent coverage and / or low mobility requirement, it might be sufficient that WUR supports only envelope detection based WUS, e.g., OOK-based signal reception. On the other hand, it is beneficial that WUR may receive at least an OFDM-based signal in use cases with stricter coverage target and / or high mobility.Particular embodiments support additional WUS information that can be received by a WUR capable of OFDM-based signal reception.Figure 4 illustrates a network node transmitting synchronization signal to a low-power receiver.As used herein, the term unified WUS refers to a WUS which can be received by WURs with different architectures / capabilities (e.g., WUR capable of receiving OOK-based signal only, OFDM-based signal only, or both).Particular embodiments include additional WUS information and WUS information structure. In these embodiments, the WUS transmitted to a UE contains additional information that may be received by a WUR capable of OFDM-based signal reception.The following embodiments include a unified WUS comprising an OOK waveform / pattem where OFDM sequences are transmitted during the ON durations of the OOK pattern (see Figure 5 which illustrates a unified WUS based on OOK waveform where some specific OFDM-based sequences are used during the ON duration of the OOK pattern.). Two sets of information contained in WUS are considered. WUSOOK is information modulated on the OOK pattern that can be received at least by a low-capability WUR such as a WUR capable of receiving an OOK signal (a more capable WUR may also detect this). WUSOFDM is information modulated on the OFDM sequences carried over the unified WUS that can be received by a more capable WUR such as an OFDM-based WUR.In one embodiment, the WUS information (WUSOFDM) modulated in the OFDM sequences used during the ON duration of the unified WUS contains additional information (WUSadditionai) compared to the information modulated on the OOK pattern (WUSOOK).In another related embodiment, WUS information modulated / carried in the OOK pattern and WUS information modulated / carried in the OFDM sequences transmitted during the ON durations of the OOK pattern are of a nested structure. For example, the same common information (WUSOOK) is carried in both the OOK pattern and the OFDM sequences, and additional information (WUSadditionai) is carried in the OFDM sequences (this is because OFDM-based WUS is more efficient and can carry more information than OOK-based WUS). In this way, a WUR capable of OOK detection receives only WUSOOK, while a WUR capable of OFDM-based signal reception receives WUSOOK and WUSadditionai. The common WUS information (WUSOOK) received by any WUR may contain general information, e.g., the WUS itself and the UE subgroup being addressed. In one example, the common WUS information (WUSOOK) and additional WUS information (WUSadditionai) with the combined total size of M bits modulated in the OFDM signal are structured such that the most significant N bits are for WUSOOK and the least significant M-N bits are for WUSadditionai.In some embodiments, the additional information (WUSadditionai) contained in WUSOFDM received by a WUR capable of OFDM-based signal reception provides additional information beneficial for WUR operation. Non-limiting examples of such additional information include:• Additional WUS UE subgroup information (further reducing false paging rate for OFDMbased WUR).• Cell ID (to combat intercell interference)• WUR configuration index information (similar to system information configuration index, informing the UE that the WUR configuration in this cell is the same as in a previous cell).• Synchronization information• Number of paging occasions (POs) the UE shall monitor if a WUS addressed to the UE’s subgroup is detected.• Additional information used to reduce the blind decoding complexity at the UE (and in particular WUR). For example, in case of PDCCH decoding, information regarding the PDCCH aggregation level (AL) and number of PDCCH candidates to be monitored can reduce the number of blind decoding attempts, thus reducing the UE complexity and power consumption.• Information related to WUR measurements, e.g., to indicate which reference signal to perform subsequent / future measurements, or how often to perform measurements, etc.• Information related to system information (SI) update notification, ETWS / CMAS information, or any other information contained in the ‘short message’ in paging, tracking area information, and RAN area information.• Moreover, such additional information carried by a WUS can be used for the main receiver operation, depending on the interaction and information exchange between the WUR and the main receiver. For example:• To provide information regarding the measurement relaxation for the main receiver.• To provide information regarding main receiver sleep mode. For example, depending on the traffic activity, the network can provide assisted information for the main receiver in terms of a suitable sleep mode such as ultra-deep sleep, deep sleep, light sleep, micro sleep. Each sleep mode is associated with a specific power consumption and transition energy and transition time for receiver ramp-up / ramp- down.In some embodiments, the additional information (WUSadditionai) contained in WUSOFDM received by a WUR capable of OFDM-based signal reception provide an indication / command to the UE, e.g.,:• Indication of the length of the PDCCH monitoring window the UE shall apply if a WUS addressed to the UE’s subgroup is detected. (Preconfigured and indicated by a configuration index, e.g., index=

[0001] means t2).• Indication of PDCCH search space used for WUR operation. For example, to indicate a search space ID used for receiving a PDCCH after the main radio (MR) wakes up.• Indication of a downlink bandwidth part (BWP) which the UE should apply for the monitoring of the paging occasion (PO) and PDCCH. I.e., unlike legacy operation the PO could be located in another BWP than the initial DL BWP.• Indication of which cell groups the UE should be woken up to monitor PDCCH (applicable in RRC Connected). This could be done similar to the ‘SCell dormancy indication’ in DCI format 2_6.• Indication of a paging resource. For example, multiple paging occasions are associated with the UE detecting WUS. The additional information can be used to indicate the intended paging occasion to be used.• Indication of a carrier to use for WUS monitoring in case that UE is configured with multiple components carriers.• Indication of a carrier to use for paging reception in case that UE is configured with multiple components carriers.• Command to switch a WUS reception mode at the UE, e.g., between OOK and OFDM WUS reception for WUR capable of both OOK detection and OFDM reception.• The switching mechanism or WUR selection method depends on several factors including coverage condition, latency target, active power consumption of OOK- WUR and OFDM-WUR, WUS payload, and WUS duration.• Command to (activate and / or) deactivate the WUR operation at the UE. That is, if the WUS indicates that WUR operation should be deactivated, the UE returns to the legacy procedure after the main radio (MR) wakes up.• Command to switch WUR operation mode.• New duty-cycle parameters / configurations for WUR, changing duty-cycled WUR operation to continuous (always-on) WUR operation.• This can be based on latency target, coverage condition, use case, UE (and WUR) battery status.In some embodiments, the additional information (WUS additional) contained in WUSOFDM and received by a WUR capable of OFDM-based signal reception provides extra functionality to the UE, e.g., :• The additional information is used to improve the detection reliability by providing error detection and error correction capabilities. For example, as illustrated in Figure 6, considering M total bits of the WUSOFDM composing of WUS 1 carrying N information bits and WUS2 carrying (M-N) bits, WUS2 can act as a cyclic redundancy check (CRC) forWUS1 to reduce the false alarm probabilities. Minimizing false alarms (false detections) is crucial for the UE energy efficiency as it avoids unnecessary wake up events which results in the waste of energy.• In another example, WUS2 and WUS1 can be related, and the receiver can use such a relation for enhancing its detection performance. For example:• WUS2 can be a specific function of WU S 1.• WUS2 can be a repeated version of WUS1.In some embodiments, the additional WUS information WUSadditionai may be configured to be absent.In the embodiments described above, the unified WUS may for example be based on any OOK pattern. One option of the OOK pattern is to use an OOK pattern which has equal number of ON and OFF durations / segments. This can be realized, e.g., by using Manchester coding for OOK modulation.Some embodiments include separate information in OOK-based WUS part and the OFDMbased WUS part. For example, in the unified WUS, the information sent in the OOK-based part of the WUS (WUSOOK) and the information sent in the OFDM-based part of WUS (WUSOFDM) are separate. That is, WUSOFDM is not equal to (WUSOOK plus additional OFDM-info).In some embodiments, the OOK-based WUR UEs and the OFDM-based WUR UEs are considered to belong to different WUS UE subgroups. When a UE supports either OOK-based WUR or OFDM-based WUR (all RRC states), or for RRC Connected where the gNB knows which WUR the UE is applying (if the UE supports both OOK-based WUR and OFDM-based WUR), this will reduce the false paging and lead to larger UE power saving gain from the WUR feature. For example, if the UE subgroup indication is separate in the OOK-part of the WUS and the OFDM-part of the WUS, a UE operating using OFDM-based WUR would not wake up the main receiver to monitor PDCCH if the OOK-based part of the WUS indicates its own UE subgroup, but would wake up only if the OFDM-based part of the WUS indicated its own UE subgroup (and vice versa for a UE operating using an OOK-based WUR). In this way, if there is paging for a UE using OFDM-based WUR that belongs to UE subgroup 3, and paging for a UE using OOK-based WUR which belongs to UE subgroup 2, the gNB can address them simultaneously by indicating subgroup 3 in the OFDM-based part of the WUS, and subgroup 2 in the OOK-based part of the WUS (which is not possible if the OOK-based info WUSOOK is always common).In some embodiments, the OFDM-based WUR includes more ‘WUS monitoring occasions’ than for OOK-based WUR (as illustrated in Figure 7). This is possible if the OOK-based WUScontent is allowed to be different from OFDM-based WUS content and would reduce false paging even further.Some embodiments include unified / additional WUS transmission and monitoring.In some embodiments, a gNB transmits WUSOFDM k (0<k<D) times to improve detection and / or coverage performance, where D is the number of ON duration of the Unified WUS.In a related embodiment, a UE with OFDM-based WUR may perform early termination of WUS monitoring after detecting x (x>0) OFDM sequences.In some embodiments, if the pay load of WUSOOK is large, adding additional information to the payload might increase the complexity of OFDM sequence design and / or reach the bottleneck of WUS bandwidth. In such cases, WUSadditionai may be transmitted separately from WUSOFDM, i.e., WUSadditionai is not contained in WUSOFDM and thus WUSOFDM = WUSOOK.In view of the embodiments described above, a first aspect provides embodiments of a method 800 performed by a wireless device (for example a UE), as illustrated in Figure 8. The method 800 comprises receiving 810, from a network node, a wake up signal (WUS) comprising an on-off keyed (OOK) pattern where orthogonal frequency division multiplexing (OFDM) sequences are transmitted during ON durations of the OOK pattern. First information is carried by the OOK pattern and second information is carried by the OFDM sequences. The second information includes additional information not included in the first information.According to some embodiments, the method 800 may comprise obtaining 820 the first information from the WUS, and / or obtaining 830 the second information from the WUS.According to some embodiments, the method 800 may comprise waking up 840 a main receiver based on one or more of the first information and the second information to monitor a physical downlink control channel (PDCCH).In view of the embodiments described above, a second aspect provides a method 900 performed by a network node (for example a base station), as illustrated in Figure 9. The method 900 comprises transmitting 910 a wake up signal (WUS) comprising an on-off keyed (OOK) pattern where orthogonal frequency division multiplexing (OFDM) sequences are transmitted during ON durations of the OOK pattern. First information is carried by the OOK pattern and second information is carried by the OFDM sequences. The second information includes additional information not included in the first information.Some embodiments include additional information in a (low power synchronization signal) LP-SS structure.In some embodiments, the LP-SS contains some information intended for (a group of) UEs.In some embodiments, for an LP-SS structure that is based on an OOK pattern where some OFDM sequences are used during the ON durations, information contained in the LP-SS may be modulated onto the OFDM signal part of the LP-SS. That is, a UE with a WUR capable of OFDMbased signal reception receives the information contained in the LP-SS.Different solutions for LP-SS containing some information may include, for example:• The OOK pattem / waveform serves as a synchronization signal for a WUR. In a related solution, the OOK waveform can also carry some information (e.g., via the use of multiple OOK sequences).• The OFDM signal part of the LP-SS serves as a synchronization signal and carries additional information. In one example, the additional information is carried via the use of multiple OFDM sequences defined as candidate sequences for OFDM signal transmitted during the ON duration of the OOK pattern.The additional information contained in the LP-SS can be used for different purposes, for example:• To provide system information related to WUR operation to the UE.• To provide information related to the cell ID.• To provide additional timing information.• To provide information related to measurements, e.g. measurement modes.• To indicate a change in measurement mode, e.g., switch between LP-SS based and SSS- based measurements.• Moreover, as previously discussed, such additional information carried by the LP-SS can be used for the main receiver operation, depending on the interaction and information exchange between the WUR and main receiver.• To provide some WUR-specific information, e.g., to indicate whether the cell supports OFDM-based WUR operation or not.In some embodiments, the LP-SS is low-power synchronization signal transmitted periodically to UEs in a cell. It is intended for UE operating with LP-WUS monitoring to use for (rough) time and frequency sync when the UE is in WUS monitoring mode (e.g., main receiver is off and only WUR is on). In some sense, the LP-WUS can be considered as sync signal for WUR (a replacement or complement to SSB for the main receiver). It is however possible that a LP- WUR capable of OFDM reception may only use SSB and not LP-SS, or it may use both.In some embodiments, the LP-SS carries some useful information which can be used by a UE and / or a LP-WUR. That is, the LP-SS here can serve dual functions, namely for sync and for providing some information. As described above, the LP-SS may carry different types of information.In view of the embodiments described above, a third aspect provides embodiments of a method 1000 performed by a wireless device (for example a UE), as illustrated in Figure 10. The method 1000 comprises receiving 1010, from a network node, a synchronization signal (for example a LP-SS) comprising an on-off keyed (OOK) pattern where orthogonal frequency division multiplexing (OFDM) sequences are transmitted during ON durations of the OOK pattern. Information is carried by the OFDM sequences. The method 1000 further comprises using 1020 at least part of the synchronization signal as a synchronization signal for a wake up receiver (WUR).According to some embodiments, the method 1000 further comprises receiving 1030 the information carried by the OFDM sequences and / or information carried by the OOK sequence.According to some embodiments, the method 1000 further comprises receiving 1040, from the network node, a wake up signal (WUS) comprising an OOK pattern where OFDM sequences are transmitted during ON durations of the OOK pattern. First information is carried by the OOK pattern in the WUS and second information is carried by the OFDM sequences in the WUS. The WUS may for example be received using the WUR.In view of the embodiments described above, a fourth aspect provides embodiments of a method 1100 performed by a network node (for example a base station), as illustrated in Figure 11. The method 1100 comprises transmitting 1110 a synchronization signal comprising an on-off keyed (OOK) pattern where orthogonal frequency division multiplexing (OFDM) sequences are transmitted during ON durations of the OOK pattern. Information is carried by the OFDM sequences.According to some embodiments, the method 1100 further comprises transmitting 1020 a wake up signal (WUS) comprising an OOK pattern where OFDM sequences are transmitted during ON durations of the OOK pattern. First information is carried by the OOK pattern in the WUS and second information is carried by the OFDM sequences in the WUS.Figure 12 shows an example of a communication system 1200 in accordance with some embodiments. In the example, the communication system 1200 includes a telecommunication network 1202 that includes an access network 1204, such as a radio access network (RAN), and a core network 1206, which includes one or more core network nodes 1208. The access network1204 includes one or more access network nodes, such as network nodes 1210a and 1210b (one or more of which may be generally referred to as network nodes 1210), or any other similar 3rd Generation Partnership Project (3GPP) access node or non-3GPP access point. The network nodes 1210 facilitate direct or indirect connection of user equipment (UE), such as by connecting UEs 1212a, 1212b, 1212c, and 1212d (one or more of which may be generally referred to as UEs 1212) to the core network 1206 over one or more wireless connections.Example wireless communications over a wireless connection include transmitting and / or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and / or other types of signals suitable for conveying information without the use of wires, cables, or other material conductors. Moreover, in different embodiments, the communication system 1200 may include any number of wired or wireless networks, network nodes, UEs, and / or any other components or systems that may facilitate or participate in the communication of data and / or signals whether via wired or wireless connections. The communication system 1200 may include and / or interface with any type of communication, telecommunication, data, cellular, radio network, and / or other similar type of system.The UEs 1212 may be any of a wide variety of communication devices, including wireless devices arranged, configured, and / or operable to communicate wirelessly with the network nodes 1210 and other communication devices. Similarly, the network nodes 1210 are arranged, capable, configured, and / or operable to communicate directly or indirectly with the UEs 1212 and / or with other network nodes or equipment in the telecommunication network 1202 to enable and / or provide network access, such as wireless network access, and / or to perform other functions, such as administration in the telecommunication network 1202.In the depicted example, the core network 1206 connects the network nodes 1210 to one or more hosts, such as host 1216. These connections may be direct or indirect via one or more intermediary networks or devices. In other examples, network nodes may be directly coupled to hosts. The core network 1206 includes one more core network nodes (e.g., core network node 1208) that are structured with hardware and software components. Features of these components may be substantially similar to those described with respect to the UEs, network nodes, and / or hosts, such that the descriptions thereof are generally applicable to the corresponding components of the core network node 1208. Example core network nodes include functions of one or more of a Mobile Switching Center (MSC), Mobility Management Entity (MME), Home Subscriber Server (HSS), Access and Mobility Management Function (AMF), Session Management Function (SMF), Authentication Server Function (AUSF), Subscription Identifier De-concealing function(SIDF), Unified Data Management (UDM), Security Edge Protection Proxy (SEPP), Network Exposure Function (NEF), and / or a User Plane Function (UPF).The host 1216 may be under the ownership or control of a service provider other than an operator or provider of the access network 1204 and / or the telecommunication network 1202, and may be operated by the service provider or on behalf of the service provider. The host 1216 may host a variety of applications to provide one or more service. Examples of such applications include live and pre-recorded audio / video content, data collection services such as retrieving and compiling data on various ambient conditions detected by a plurality of UEs, analytics functionality, social media, functions for controlling or otherwise interacting with remote devices, functions for an alarm and surveillance center, or any other such function performed by a server.As a whole, the communication system 1200 of Figure 12 enables connectivity between the UEs, network nodes, and hosts. In that sense, the communication system may be configured to operate according to predefined rules or procedures, such as specific standards that include, but are not limited to: Global System for Mobile Communications (GSM); Universal Mobile Telecommunications System (UMTS); Long Term Evolution (LTE), and / or other suitable 2G, 3G, 4G, 5G standards, or any applicable future generation standard (e.g., 6G); wireless local area network (WLAN) standards, such as the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards (WiFi); and / or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave, Near Field Communication (NFC) ZigBee, LiFi, and / or any low-power wide-area network (LPWAN) standards such as LoRa and Sigfox.In some examples, the telecommunication network 1202 is a cellular network that implements 3GPP standardized features. Accordingly, the telecommunications network 1202 may support network slicing to provide different logical networks to different devices that are connected to the telecommunication network 1202. For example, the telecommunications network 1202 may provide Ultra Reliable Low Latency Communication (URLLC) services to some UEs, while providing Enhanced Mobile Broadband (eMBB) services to other UEs, and / or Massive Machine Type Communication (mMTC) / Massive loT services to yet further UEs.In some examples, the UEs 1212 are configured to transmit and / or receive information without direct human interaction. For instance, a UE may be designed to transmit information to the access network 1204 on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the access network 1204. Additionally, a UE may be configured for operating in single- or multi-RAT or multi-standard mode. For example, a UE mayoperate with any one or combination of Wi-Fi, NR (New Radio) and LTE, i.e. being configured for multi-radio dual connectivity (MR-DC), such as E-UTRAN (Evolved-UMTS Terrestrial Radio Access Network) New Radio - Dual Connectivity (EN-DC).In the example, the hub 1214 communicates with the access network 1204 to facilitate indirect communication between one or more UEs (e.g., UE 1212c and / or 1212d) and network nodes (e.g., network node 1210b). In some examples, the hub 1214 may be a controller, router, content source and analytics, or any of the other communication devices described herein regarding UEs. For example, the hub 1214 may be a broadband router enabling access to the core network 1206 for the UEs. As another example, the hub 1214 may be a controller that sends commands or instructions to one or more actuators in the UEs. Commands or instructions may be received from the UEs, network nodes 1210, or by executable code, script, process, or other instructions in the hub 1214. As another example, the hub 1214 may be a data collector that acts as temporary storage for UE data and, in some embodiments, may perform analysis or other processing of the data. As another example, the hub 1214 may be a content source. For example, for a UE that is a VR headset, display, loudspeaker or other media delivery device, the hub 1214 may retrieve VR assets, video, audio, or other media or data related to sensory information via a network node, which the hub 1214 then provides to the UE either directly, after performing local processing, and / or after adding additional local content. In still another example, the hub 1214 acts as a proxy server or orchestrator for the UEs, in particular in if one or more of the UEs are low energy loT devices.The hub 1214 may have a constant / persistent or intermittent connection to the network node 1210b. The hub 1214 may also allow for a different communication scheme and / or schedule between the hub 1214 and UEs (e.g., UE 1212c and / or 1212d), and between the hub 1214 and the core network 1206. In other examples, the hub 1214 is connected to the core network 1206 and / or one or more UEs via a wired connection. Moreover, the hub 1214 may be configured to connect to an M2M service provider over the access network 1204 and / or to another UE over a direct connection. In some scenarios, UEs may establish a wireless connection with the network nodes 1210 while still connected via the hub 1214 via a wired or wireless connection. In some embodiments, the hub 1214 may be a dedicated hub - that is, a hub whose primary function is to route communications to / from the UEs from / to the network node 1210b. In other embodiments, the hub 1214 may be a non-dedicated hub - that is, a device which is capable of operating to route communications between the UEs and network node 1210b, but which is additionally capable of operating as a communication start and / or end point for certain data channels.Figure 13 shows a UE 1300 in accordance with some embodiments. As used herein, a UE refers to a device capable, configured, arranged and / or operable to communicate wirelessly with network nodes and / or other UEs. Examples of a UE include, but are not limited to, a smart phone, mobile phone, cell phone, voice over IP (VoIP) phone, wireless local loop phone, desktop computer, personal digital assistant (PDA), wireless cameras, gaming console or device, music storage device, playback appliance, wearable terminal device, wireless endpoint, mobile station, tablet, laptop, laptop-embedded equipment (LEE), laptop-mounted equipment (LME), smart device, wireless customer-premise equipment (CPE), vehicle-mounted or vehicle embedded / integrated wireless device, etc. Other examples include any UE identified by the 3rd Generation Partnership Project (3GPP), including a narrow band internet of things (NB-IoT) UE, a machine type communication (MTC) UE, and / or an enhanced MTC (eMTC) UE.A UE may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, Dedicated Short-Range Communication (DSRC), vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), or vehicle-to-everything (V2X). In other examples, a UE may not necessarily have a user in the sense of a human user who owns and / or operates the relevant device. Instead, a UE may represent a device that is intended for sale to, or operation by, a human user but which may not, or which may not initially, be associated with a specific human user (e.g., a smart sprinkler controller). Alternatively, a UE may represent a device that is not intended for sale to, or operation by, an end user but which may be associated with or operated for the benefit of a user (e.g., a smart power meter).The UE 1300 includes processing circuitry 1302 that is operatively coupled via a bus 1304 to an input / output interface 1306, apower source 1308, amemory 1310, a communication interface 1312, and / or any other component, or any combination thereof. Certain UEs may utilize all or a subset of the components shown in Figure 13. The level of integration between the components may vary from one UE to another UE. Further, certain UEs may contain multiple instances of a component, such as multiple processors, memories, transceivers, transmitters, receivers, etc.The processing circuitry 1302 is configured to process instructions and data and may be configured to implement any sequential state machine operative to execute instructions stored as machine-readable computer programs in the memory 1310. The processing circuitry 1302 may be implemented as one or more hardware-implemented state machines (e.g., in discrete logic, field- programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.); programmable logic together with appropriate firmware; one or more stored computer programs, general-purpose processors, such as a microprocessor or digital signal processor (DSP), togetherwith appropriate software; or any combination of the above. For example, the processing circuitry 1302 may include multiple central processing units (CPUs).In the example, the input / output interface 1306 may be configured to provide an interface or interfaces to an input device, output device, or one or more input and / or output devices. Examples of an output device include a speaker, a sound card, a video card, a display, a monitor, a printer, an actuator, an emitter, a smartcard, another output device, or any combination thereof. An input device may allow a user to capture information into the UE 1300. Examples of an input device include a touch-sensitive or presence-sensitive display, a camera (e.g., a digital camera, a digital video camera, a web camera, etc.), a microphone, a sensor, a mouse, a trackball, a directional pad, a trackpad, a scroll wheel, a smartcard, and the like. The presence-sensitive display may include a capacitive or resistive touch sensor to sense input from a user. A sensor may be, for instance, an accelerometer, a gyroscope, a tilt sensor, a force sensor, a magnetometer, an optical sensor, a proximity sensor, a biometric sensor, etc., or any combination thereof. An output device may use the same type of interface port as an input device. For example, a Universal Serial Bus (USB) port may be used to provide an input device and an output device.In some embodiments, the power source 1308 is structured as a battery or battery pack. Other types of power sources, such as an external power source (e.g., an electricity outlet), photovoltaic device, or power cell, may be used. The power source 1308 may further include power circuitry for delivering power from the power source 1308 itself, and / or an external power source, to the various parts of the UE 1300 via input circuitry or an interface such as an electrical power cable. Delivering power may be, for example, for charging of the power source 1308. Power circuitry may perform any formatting, converting, or other modification to the power from the power source 1308 to make the power suitable for the respective components of the UE 1300 to which power is supplied.The memory 1310 may be or be configured to include memory such as random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disks, optical disks, hard disks, removable cartridges, flash drives, and so forth. In one example, the memory 1310 includes one or more application programs 1314, such as an operating system, web browser application, a widget, gadget engine, or other application, and corresponding data 1316. The memory 1310 may store, for use by the UE 1300, any of a variety of various operating systems or combinations of operating systems.The memory 1310 may be configured to include a number of physical drive units, such as redundant array of independent disks (RAID), flash memory, USB flash drive, external hard disk drive, thumb drive, pen drive, key drive, high-density digital versatile disc (HD-DVD) optical disc drive, internal hard disk drive, Blu-Ray optical disc drive, holographic digital data storage (HDDS) optical disc drive, external mini-dual in-line memory module (DIMM), synchronous dynamic random access memory (SDRAM), external micro-DIMM SDRAM, smartcard memory such as tamper resistant module in the form of a universal integrated circuit card (UICC) including one or more subscriber identity modules (SIMs), such as a USIM and / or ISIM, other memory, or any combination thereof. The UICC may for example be an embedded UICC (eUICC), integrated UICC (iUICC) or a removable UICC commonly known as ‘SIM card.’ The memory 1310 may allow the UE 1300 to access instructions, application programs and the like, stored on transitory or non-transitory memory media, to off-load data, or to upload data. An article of manufacture, such as one utilizing a communication system may be tangibly embodied as or in the memory 1310, which may be or comprise a device-readable storage medium.The processing circuitry 1302 may be configured to communicate with an access network or other network using the communication interface 1312. The communication interface 1312 may comprise one or more communication subsystems and may include or be communicatively coupled to an antenna 1322. The communication interface 1312 may include one or more transceivers used to communicate, such as by communicating with one or more remote transceivers of another device capable of wireless communication (e.g., another UE or a network node in an access network). Each transceiver may include a transmitter 1318 and / or a receiver 1320 appropriate to provide network communications (e.g., optical, electrical, frequency allocations, and so forth). Moreover, the transmitter 1318 and receiver 1320 may be coupled to one or more antennas (e.g., antenna 1322) and may share circuit components, software or firmware, or alternatively be implemented separately.In the illustrated embodiment, communication functions of the communication interface 1312 may include cellular communication, Wi-Fi communication, LPWAN communication, data communication, voice communication, multimedia communication, short-range communications such as Bluetooth, near-field communication, location-based communication such as the use of the global positioning system (GPS) to determine a location, another like communication function, or any combination thereof. Communications may be implemented in according to one or more communication protocols and / or standards, such as IEEE 802.11, Code Division Multiplexing Access (CDMA), Wideband Code Division Multiple Access (WCDMA), GSM, LTE, New Radio(NR), UMTS, WiMax, Ethernet, transmission control protocol / intemet protocol (TCP / IP), synchronous optical networking (SONET), Asynchronous Transfer Mode (ATM), QUIC, Hypertext Transfer Protocol (HTTP), and so forth.Regardless of the type of sensor, a UE may provide an output of data captured by its sensors, through its communication interface 1312, via a wireless connection to a network node. Data captured by sensors of a UE can be communicated through a wireless connection to a network node via another UE. The output may be periodic (e.g., once every 15 minutes if it reports the sensed temperature), random (e.g., to even out the load from reporting from several sensors), in response to a triggering event (e.g., when moisture is detected an alert is sent), in response to a request (e.g., a user initiated request), or a continuous stream (e.g., a live video feed of a patient).As another example, a UE comprises an actuator, a motor, or a switch, related to a communication interface configured to receive wireless input from a network node via a wireless connection. In response to the received wireless input the states of the actuator, the motor, or the switch may change. For example, the UE may comprise a motor that adjusts the control surfaces or rotors of a drone in flight according to the received input or to a robotic arm performing a medical procedure according to the received input.A UE, when in the form of an Internet of Things (loT) device, may be a device for use in one or more application domains, these domains comprising, but not limited to, city wearable technology, extended industrial application and healthcare. Non-limiting examples of such an loT device are a device which is or which is embedded in: a connected refrigerator or freezer, a TV, a connected lighting device, an electricity meter, a robot vacuum cleaner, a voice controlled smart speaker, a home security camera, amotion detector, a thermostat, asmoke detector, adoor / window sensor, a flood / moisture sensor, an electrical door lock, a connected doorbell, an air conditioning system like a heat pump, an autonomous vehicle, a surveillance system, a weather monitoring device, a vehicle parking monitoring device, an electric vehicle charging station, a smart watch, a fitness tracker, a head-mounted display for Augmented Reality (AR) or Virtual Reality (VR), a wearable for tactile augmentation or sensory enhancement, a water sprinkler, an animal- or itemtracking device, a sensor for monitoring a plant or animal, an industrial robot, an Unmanned Aerial Vehicle (UAV), and any kind of medical device, like a heart rate monitor or a remote controlled surgical robot. A UE in the form of an loT device comprises circuitry and / or software in dependence of the intended application of the loT device in addition to other components as described in relation to the UE 1300 shown in Figure 13.As yet another specific example, in an loT scenario, a UE may represent a machine or other device that performs monitoring and / or measurements, and transmits the results of such monitoring and / or measurements to another UE and / or a network node. The UE may in this case be an M2M device, which may in a 3GPP context be referred to as an MTC device. As one particular example, the UE may implement the 3GPP NB-IoT standard. In other scenarios, a UE may represent a vehicle, such as a car, a bus, a truck, a ship and an airplane, or other equipment that is capable of monitoring and / or reporting on its operational status or other functions associated with its operation.In practice, any number of UEs may be used together with respect to a single use case. For example, a first UE might be or be integrated in a drone and provide the drone’s speed information (obtained through a speed sensor) to a second UE that is a remote controller operating the drone. When the user makes changes from the remote controller, the first UE may adjust the throttle on the drone (e.g. by controlling an actuator) to increase or decrease the drone’s speed. The first and / or the second UE can also include more than one of the functionalities described above. For example, a UE might comprise the sensor and the actuator, and handle communication of data for both the speed sensor and the actuators.Figure 14 shows a network node 1400 in accordance with some embodiments. As used herein, network node refers to equipment capable, configured, arranged and / or operable to communicate directly or indirectly with a UE and / or with other network nodes or equipment, in a telecommunication network. Examples of network nodes include, but are not limited to, access points (APs) (e.g., radio access points), base stations (BSs) (e.g., radio base stations, Node Bs, evolved Node Bs (eNBs) and NR NodeBs (gNBs)).Base stations may be categorized based on the amount of coverage they provide (or, stated differently, their transmit power level) and so, depending on the provided amount of coverage, may be referred to as femto base stations, pico base stations, micro base stations, or macro base stations. A base station may be a relay node or a relay donor node controlling a relay. A network node may also include one or more (or all) parts of a distributed radio base station such as centralized digital units and / or remote radio units (RRUs), sometimes referred to as Remote Radio Heads (RRHs). Such remote radio units may or may not be integrated with an antenna as an antenna integrated radio. Parts of a distributed radio base station may also be referred to as nodes in a distributed antenna system (DAS).Other examples of network nodes include multiple transmission point (multi-TRP) 5G access nodes, multi-standard radio (MSR) equipment such as MSR BSs, network controllers suchas radio network controllers (RNCs) or base station controllers (BSCs), base transceiver stations (BTSs), transmission points, transmission nodes, multi-cell / multicast coordination entities (MCEs), Operation and Maintenance (O&M) nodes, Operations Support System (OSS) nodes, Self-Organizing Network (SON) nodes, positioning nodes (e.g., Evolved Serving Mobile Location Centers (E-SMLCs)), and / or Minimization of Drive Tests (MDTs).The network node 1400 includes a processing circuitry 1402, a memory 1404, a communication interface 1406, and a power source 1408. The network node 1400 may be composed of multiple physically separate components (e.g., a NodeB component and a RNC component, or a BTS component and a BSC component, etc.), which may each have their own respective components. In certain scenarios in which the network node 1400 comprises multiple separate components (e.g., BTS and BSC components), one or more of the separate components may be shared among several network nodes. For example, a single RNC may control multiple NodeBs. In such a scenario, each unique NodeB and RNC pair, may in some instances be considered a single separate network node. In some embodiments, the network node 1400 may be configured to support multiple radio access technologies (RATs). In such embodiments, some components may be duplicated (e.g., separate memory 1404 for different RATs) and some components may be reused (e.g., a same antenna 1410 may be shared by different RATs). The network node 1400 may also include multiple sets of the various illustrated components for different wireless technologies integrated into network node 1400, for example GSM, WCDMA, LTE, NR, WiFi, Zigbee, Z-wave, LoRaWAN, Radio Frequency Identification (RFID) or Bluetooth wireless technologies. These wireless technologies may be integrated into the same or different chip or set of chips and other components within network node 1400.The processing circuitry 1402 may comprise a combination of one or more of a microprocessor, controller, microcontroller, central processing unit, digital signal processor, application-specific integrated circuit, field programmable gate array, or any other suitable computing device, resource, or combination of hardware, software and / or encoded logic operable to provide, either alone or in conjunction with other network node 1400 components, such as the memory 1404, to provide network node 1400 functionality.In some embodiments, the processing circuitry 1402 includes a system on a chip (SOC). In some embodiments, the processing circuitry 1402 includes one or more of radio frequency (RF) transceiver circuitry 1412 and baseband processing circuitry 1414. In some embodiments, the radio frequency (RF) transceiver circuitry 1412 and the baseband processing circuitry 1414 may be on separate chips (or sets of chips), boards, or units, such as radio units and digital units. In alternativeembodiments, part or all of RF transceiver circuitry 1412 and baseband processing circuitry 1414 may be on the same chip or set of chips, boards, or units.The memory 1404 may comprise any form of volatile or non-volatile computer-readable memory including, without limitation, persistent storage, solid-state memory, remotely mounted memory, magnetic media, optical media, random access memory (RAM), read-only memory (ROM), mass storage media (for example, a hard disk), removable storage media (for example, a flash drive, a Compact Disk (CD) or a Digital Video Disk (DVD)), and / or any other volatile or non-volatile, non-transitory device-readable and / or computer-executable memory devices that store information, data, and / or instructions that may be used by the processing circuitry 1402. The memory 1404 may store any suitable instructions, data, or information, including a computer program, software, an application including one or more of logic, rules, code, tables, and / or other instructions capable of being executed by the processing circuitry 1402 and utilized by the network node 1400. The memory 1404 may be used to store any calculations made by the processing circuitry 1402 and / or any data received via the communication interface 1406. In some embodiments, the processing circuitry 1402 and memory 1404 is integrated.The communication interface 1406 is used in wired or wireless communication of signaling and / or data between anetwork node, access network, and / or UE. As illustrated, the communication interface 1406 comprises port(s) / terminal(s) 1416 to send and receive data, for example to and from a network over a wired connection. The communication interface 1406 also includes radio front-end circuitry 1418 that may be coupled to, or in certain embodiments a part of, the antenna 1410. Radio front-end circuitry 1418 comprises filters 1420 and amplifiers 1422. The radio frontend circuitry 1418 may be connected to an antenna 1410 and processing circuitry 1402. The radio front-end circuitry may be configured to condition signals communicated between antenna 1410 and processing circuitry 1402. The radio front-end circuitry 1418 may receive digital data that is to be sent out to other network nodes or UEs via a wireless connection. The radio front-end circuitry 1418 may convert the digital data into a radio signal having the appropriate channel and bandwidth parameters using a combination of filters 1420 and / or amplifiers 1422. The radio signal may then be transmitted via the antenna 1410. Similarly, when receiving data, the antenna 1410 may collect radio signals which are then converted into digital data by the radio front-end circuitry 1418. The digital data may be passed to the processing circuitry 1402. In other embodiments, the communication interface may comprise different components and / or different combinations of components.In certain alternative embodiments, the network node 1400 does not include separate radio front-end circuitry 1418, instead, the processing circuitry 1402 includes radio front-end circuitry and is connected to the antenna 1410. Similarly, in some embodiments, all or some of the RF transceiver circuitry 1412 is part of the communication interface 1406. In still other embodiments, the communication interface 1406 includes one or more ports or terminals 1416, the radio frontend circuitry 1418, and the RF transceiver circuitry 1412, as part of a radio unit (not shown), and the communication interface 1406 communicates with the baseband processing circuitry 1414, which is part of a digital unit (not shown).The antenna 1410 may include one or more antennas, or antenna arrays, configured to send and / or receive wireless signals. The antenna 1410 may be coupled to the radio front-end circuitry 1418 and may be any type of antenna capable of transmitting and receiving data and / or signals wirelessly. In certain embodiments, the antenna 1410 is separate from the network node 1400 and connectable to the network node 1400 through an interface or port.The antenna 1410, communication interface 1406, and / or the processing circuitry 1402 may be configured to perform any receiving operations and / or certain obtaining operations described herein as being performed by the network node. Any information, data and / or signals may be received from a UE, another network node and / or any other network equipment. Similarly, the antenna 1410, the communication interface 1406, and / or the processing circuitry 1402 may be configured to perform any transmitting operations described herein as being performed by the network node. Any information, data and / or signals may be transmitted to a UE, another network node and / or any other network equipment.The power source 1408 provides power to the various components of network node 1400 in a form suitable for the respective components (e.g., at a voltage and current level needed for each respective component). The power source 1408 may further comprise, or be coupled to, power management circuitry to supply the components of the network node 1400 with power for performing the functionality described herein. For example, the network node 1400 may be connectable to an external power source (e.g., the power grid, an electricity outlet) via an input circuitry or interface such as an electrical cable, whereby the external power source supplies power to power circuitry of the power source 1408. As a further example, the power source 1408 may comprise a source of power in the form of a battery or battery pack which is connected to, or integrated in, power circuitry. The battery may provide backup power should the external power source fail.Embodiments of the network node 1400 may include additional components beyond those shown in Figure 14 for providing certain aspects of the network node’s functionality, including any of the functionality described herein and / or any functionality necessary to support the subject matter described herein. For example, the network node 1400 may include user interface equipment to allow input of information into the network node 1400 and to allow output of information from the network node 1400. This may allow a user to perform diagnostic, maintenance, repair, and other administrative functions for the network node 1400.Figure 15 is a block diagram of a host 1500, which may be an embodiment of the host 1216 of Figure 12, in accordance with various aspects described herein. As used herein, the host 1500 may be or comprise various combinations hardware and / or software, including a standalone server, a blade server, a cloud-implemented server, a distributed server, a virtual machine, container, or processing resources in a server farm. The host 1500 may provide one or more services to one or more UEs.The host 1500 includes processing circuitry 1502 that is operatively coupled via a bus 1504 to an input / output interface 1506, a network interface 1508, a power source 1510, and a memory 1512. Other components may be included in other embodiments. Features of these components may be substantially similar to those described with respect to the devices of previous figures, such as Figures 13 and 14, such that the descriptions thereof are generally applicable to the corresponding components of host 1500.The memory 1512 may include one or more computer programs including one or more host application programs 1514 and data 1516, which may include user data, e.g., data generated by a UE for the host 1500 or data generated by the host 1500 for a UE. Embodiments of the host 1500 may utilize only a subset or all of the components shown. The host application programs 1514 may be implemented in a container-based architecture and may provide support for video codecs (e.g., Versatile Video Coding (VVC), High Efficiency Video Coding (HEVC), Advanced Video Coding (AVC), MPEG, VP9) and audio codecs (e.g., FLAC, Advanced Audio Coding (AAC), MPEG, G.711), including transcoding for multiple different classes, types, or implementations of UEs (e.g., handsets, desktop computers, wearable display systems, heads-up display systems). The host application programs 1514 may also provide for user authentication and licensing checks and may periodically report health, routes, and content availability to a central node, such as a device in or on the edge of a core network. Accordingly, the host 1500 may select and / or indicate a different host for over-the-top services for a UE. The host application programs 1514 may support various protocols, such as the HTTP Live Streaming (HLS) protocol, Real-Time MessagingProtocol (RTMP), Real-Time Streaming Protocol (RTSP), Dynamic Adaptive Streaming over HTTP (MPEG-DASH), etc.Figure 16 is a block diagram illustrating a virtualization environment 1600 in which functions implemented by some embodiments may be virtualized. In the present context, virtualizing means creating virtual versions of apparatuses or devices which may include virtualizing hardware platforms, storage devices and networking resources. As used herein, virtualization can be applied to any device described herein, or components thereof, and relates to an implementation in which at least a portion of the functionality is implemented as one or more virtual components. Some or all of the functions described herein may be implemented as virtual components executed by one or more virtual machines (VMs) implemented in one or more virtual environments 1600 hosted by one or more of hardware nodes, such as a hardware computing device that operates as a network node, UE, core network node, or host. Further, in embodiments in which the virtual node does not require radio connectivity (e.g., a core network node or host), then the node may be entirely virtualized.Applications 1602 (which may alternatively be called software instances, virtual appliances, network functions, virtual nodes, virtual network functions, etc.) are run in the virtualization environment Q400 to implement some of the features, functions, and / or benefits of some of the embodiments disclosed herein.Hardware 1604 includes processing circuitry, memory that stores software and / or instructions executable by hardware processing circuitry, and / or other hardware devices as described herein, such as a network interface, input / output interface, and so forth. Software may be executed by the processing circuitry to instantiate one or more virtualization layers 1606 (also referred to as hypervisors or virtual machine monitors (VMMs)), provide VMs 1608a and 1608b (one or more of which may be generally referred to as VMs 1608), and / or perform any of the functions, features and / or benefits described in relation with some embodiments described herein. The virtualization layer 1606 may present a virtual operating platform that appears like networking hardware to the VMs 1608.The VMs 1608 comprise virtual processing, virtual memory, virtual networking or interface and virtual storage, and may be run by a corresponding virtualization layer 1606. Different embodiments of the instance of a virtual appliance 1602 may be implemented on one or more of VMs 1608, and the implementations may be made in different ways. Virtualization of the hardware is in some contexts referred to as network function virtualization (NFV). NFV may be used to consolidate many network equipment types onto industry standard high volume server hardware,physical switches, and physical storage, which can be located in data centers, and customer premise equipment.In the context of NFV, a VM 1608 may be a software implementation of a physical machine that runs programs as if they were executing on a physical, non-virtualized machine. Each of the VMs 1608, and that part of hardware 1604 that executes that VM, be it hardware dedicated to that VM and / or hardware shared by that VM with others of the VMs, forms separate virtual network elements. Still in the context of NFV, a virtual network function is responsible for handling specific network functions that run in one or more VMs 1608 on top of the hardware 1604 and corresponds to the application 1602.Hardware 1604 may be implemented in a standalone network node with generic or specific components. Hardware 1604 may implement some functions via virtualization. Alternatively, hardware 1604 may be part of a larger cluster of hardware (e.g. such as in a data center or CPE) where many hardware nodes work together and are managed via management and orchestration 1610, which, among others, oversees lifecycle management of applications 1602. In some embodiments, hardware 1604 is coupled to one or more radio units that each include one or more transmitters and one or more receivers that may be coupled to one or more antennas. Radio units may communicate directly with other hardware nodes via one or more appropriate network interfaces and may be used in combination with the virtual components to provide a virtual node with radio capabilities, such as a radio access node or a base station. In some embodiments, some signaling can be provided with the use of a control system 1612 which may alternatively be used for communication between hardware nodes and radio units.Figure 17 shows a communication diagram of a host 1702 communicating via a network node 1704 with a UE 1706 over a partially wireless connection in accordance with some embodiments. Example implementations, in accordance with various embodiments, of the UE (such as a UE 1212a of Figure 12 and / or UE 1300 of Figure 13), network node (such as network node 1210a of Figure 12 and / or network node 1400 of Figure 14), and host (such as host 1216 of Figure 12 and / or host 1500 of Figure 15) discussed in the preceding paragraphs will now be described with reference to Figure 17.Like host 1500, embodiments of host 1702 include hardware, such as a communication interface, processing circuitry, and memory. The host 1702 also includes software, which is stored in or accessible by the host 1702 and executable by the processing circuitry. The software includes a host application that may be operable to provide a service to a remote user, such as the UE 1706 connecting via an over-the-top (OTT) connection 1750 extending between the UE 1706 and host1702. In providing the service to the remote user, a host application may provide user data which is transmitted using the OTT connection 1750.The network node 1704 includes hardware enabling it to communicate with the host 1702 and UE 1706. The connection 1760 may be direct or pass through a core network (like core network 1206 of Figure 12) and / or one or more other intermediate networks, such as one or more public, private, or hosted networks. For example, an intermediate network may be a backbone network or the Internet.The UE 1706 includes hardware and software, which is stored in or accessible by UE 1706 and executable by the UE’s processing circuitry. The software includes a client application, such as a web browser or operator-specific “app” that may be operable to provide a service to a human or non-human user via UE 1706 with the support of the host 1702. In the host 1702, an executing host application may communicate with the executing client application via the OTT connection 1750 terminating at the UE 1706 and host 1702. In providing the service to the user, the UE's client application may receive request data from the host's host application and provide user data in response to the request data. The OTT connection 1750 may transfer both the request data and the user data. The UE's client application may interact with the user to generate the user data that it provides to the host application through the OTT connection 1750.The OTT connection 1750 may extend via a connection 1760 between the host 1702 and the network node 1704 and via a wireless connection 1770 between the network node 1704 and the UE 1706 to provide the connection between the host 1702 and the UE 1706. The connection 1760 and wireless connection 1770, over which the OTT connection 1750 may be provided, have been drawn abstractly to illustrate the communication between the host 1702 and the UE 1706 via the network node 1704, without explicit reference to any intermediary devices and the precise routing of messages via these devices.As an example of transmitting data via the OTT connection 1750, in step 1708, the host 1702 provides user data, which may be performed by executing a host application. In some embodiments, the user data is associated with a particular human user interacting with the UE 1706. In other embodiments, the user data is associated with a UE 1706 that shares data with the host 1702 without explicit human interaction. In step 1710, the host 1702 initiates a transmission carrying the user data towards the UE 1706. The host 1702 may initiate the transmission responsive to a request transmitted by the UE 1706. The request may be caused by human interaction with the UE 1706 or by operation of the client application executing on the UE 1706. The transmission may pass via the network node 1704, in accordance with the teachings of the embodimentsdescribed throughout this disclosure. Accordingly, in step 1712, the network node 1704 transmits to the UE 1706 the user data that was carried in the transmission that the host 1702 initiated, in accordance with the teachings of the embodiments described throughout this disclosure. In step 1714, the UE 1706 receives the user data carried in the transmission, which may be performed by a client application executed on the UE 1706 associated with the host application executed by the host 1702.In some examples, the UE 1706 executes a client application which provides user data to the host 1702. The user data may be provided in reaction or response to the data received from the host 1702. Accordingly, in step 1716, the UE 1706 may provide user data, which may be performed by executing the client application. In providing the user data, the client application may further consider user input received from the user via an input / output interface of the UE 1706. Regardless ofthe specific manner in which the user data was provided, the UE 1706 initiates, in step 1718, transmission of the user data towards the host 1702 via the network node 1704. In step 1720, in accordance with the teachings of the embodiments described throughout this disclosure, the network node 1704 receives user data from the UE 1706 and initiates transmission of the received user data towards the host 1702. In step 1722, the host 1702 receives the user data carried in the transmission initiated by the UE 1706.In an example scenario, factory status information may be collected and analyzed by the host 1702. As another example, the host 1702 may process audio and video data which may have been retrieved from a UE for use in creating maps. As another example, the host 1702 may collect and analyze real-time data to assist in controlling vehicle congestion (e.g., controlling traffic lights). As another example, the host 1702 may store surveillance video uploaded by a UE. As another example, the host 1702 may store or control access to media content such as video, audio, VR or AR which it can broadcast, multicast or unicast to UEs. As other examples, the host 1702 may be used for energy pricing, remote control of non-time critical electrical load to balance power generation needs, location services, presentation services (such as compiling diagrams etc. from data collected from remote devices), or any other function of collecting, retrieving, storing, analyzing and / or transmitting data.In some examples, a measurement procedure may be provided for the purpose of monitoring data rate, latency and other factors on which the one or more embodiments improve. There may further be an optional network functionality for reconfiguring the OTT connection 1750 between the host 1702 and UE 1706, in response to variations in the measurement results. The measurement procedure and / or the network functionality for reconfiguring the OTT connection may beimplemented in software and hardware of the host 1702 and / or UE 1706. In some embodiments, sensors (not shown) may be deployed in or in association with other devices through which the OTT connection 1750 passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above, or supplying values of other physical quantities from which software may compute or estimate the monitored quantities. The reconfiguring of the OTT connection 1750 may include message format, retransmission settings, preferred routing etc.; the reconfiguring need not directly alter the operation of the network node 1704. Such procedures and functionalities may be known and practiced in the art. In certain embodiments, measurements may involve proprietary UE signaling that facilitates measurements of throughput, propagation times, latency and the like, by the host 1702. The measurements may be implemented in that software causes messages to be transmitted, in particular empty or ‘dummy’ messages, using the OTT connection 1750 while monitoring propagation times, errors, etc.Although the computing devices described herein (e.g., UEs, network nodes, hosts) may include the illustrated combination of hardware components, other embodiments may comprise computing devices with different combinations of components. It is to be understood that these computing devices may comprise any suitable combination of hardware and / or software needed to perform the tasks, features, functions and methods disclosed herein. Determining, calculating, obtaining or similar operations described herein may be performed by processing circuitry, which may process information by, for example, converting the obtained information into other information, comparing the obtained information or converted information to information stored in the network node, and / or performing one or more operations based on the obtained information or converted information, and as a result of said processing making a determination. Moreover, while components are depicted as single boxes located within a larger box, or nested within multiple boxes, in practice, computing devices may comprise multiple different physical components that make up a single illustrated component, and functionality may be partitioned between separate components. For example, a communication interface may be configured to include any of the components described herein, and / or the functionality of the components may be partitioned between the processing circuitry and the communication interface. In another example, non-computationally intensive functions of any of such components may be implemented in software or firmware and computationally intensive functions may be implemented in hardware.In certain embodiments, some or all of the functionality described herein may be provided by processing circuitry executing instructions stored on in memory, which in certain embodiments may be a computer program product in the form of a non-transitory computer-readable storage medium. In alternative embodiments, some or all of the functionality may be provided by the processing circuitry without executing instructions stored on a separate or discrete device-readable storage medium, such as in a hard-wired manner. In any of those particular embodiments, whether executing instructions stored on a non-transitory computer-readable storage medium or not, the processing circuitry can be configured to perform the described functionality. The benefits provided by such functionality are not limited to the processing circuitry alone or to other components of the computing device, but are enjoyed by the computing device as a whole, and / or by end users and a wireless network generally.EMBODIMENTSGroup A Embodiments1. A method performed by a wireless device comprising a wake up receiver (WUR) capable of orthogonal frequency division multiplexing (OFDM)-based signal reception and a main receiver, the method comprising:- receiving, from a network node, a wake up signal (WUS) comprising an on-off keyed (OOK) pattern where OFDM sequences are transmitted during the ON durations of the OOK pattern and where WUSOOK information is modulated on the OOK pattern and WUSOFDM information is modulated on the OFDM sequences; and- waking up the main receiver based on one or more of the WUSOOK information and the WUSOFDM information.2. The method of the previous embodiment, wherein the WUSOFDM information includes additional information than the WUSOOK information.3. The method of the previous embodiment, wherein the additional information comprises one or more of:- additional WUS user equipment (UE) subgroup information;- cell ID;- WUR configuration index;- synchronization information;- number of paging occasions (POs) the wireless device shall monitor;- information to reduce the blind decoding complexity at the wireless device;- information related to WUR measurements;- information related to system information (SI) update notification;- information regarding measurement relaxation for the main receiver; and- information regarding main receiver sleep mode.4. The method of any one of the previous two embodiments, wherein the additional information comprises one or more of:- indication of the length of the physical downlink control channel (PDCCH) monitoring window;- indication of PDCCH search space used for WUR operation;- indication of a downlink bandwidth part (BWP) that the wireless device should apply for monitoring paging occasions (POs) and PDCCH;- indication of which cell groups the wireless device should be woken up to monitor PDCCH;- indication of paging resource;- indication of a carrier to use for WUS monitoring;- indication of a carrier to use for paging reception;- command to switch a WUS reception mode;- command to activate or deactivate WUR operation; an- command to switch WUR operation mode.5. A method performed by a wireless device, the method comprising:- any of the wireless device steps, features, or functions described above, either alone or in combination with other steps, features, or functions described above.6. The method of the previous embodiment, further comprising one or more additional wireless device steps, features or functions described above.Group B Embodiments7. A method performed by a base station for transmitting a wakeup signal (WUS), the methodcomprising:- transmitting a wake up signal (WUS) comprising an on-off keyed (OOK) pattern where orthogonal frequency division multiplexing (OFDM) sequences are transmitted during the ON durations of the OOK pattern and where WUSOOK information is modulated on the OOK pattern and WUSOFDM information is modulated on the OFDM sequences. The method of the previous embodiment, wherein the WUSOFDM information includes additional information than the WUSOOK information. The method of the previous embodiment, wherein the additional information comprises one or more of:- additional WUS user equipment (UE) subgroup information;- cell ID;- WUR configuration index;- synchronization information;- number of paging occasions (POs) the wireless device shall monitor;- information to reduce the blind decoding complexity at the wireless device;- information related to WUR measurements;- information related to system information (SI) update notification;- information regarding measurement relaxation for the main receiver; and- information regarding main receiver sleep mode. The method of any one of the previous two embodiments, wherein the additional information comprises one or more of:- indication of the length of the physical downlink control channel (PDCCH) monitoring window;- indication of PDCCH search space used for WUR operation;- indication of a downlink bandwidth part (BWP) that the wireless device should apply for monitoring paging occasions (POs) and PDCCH;- indication of which cell groups the wireless device should be woken up to monitor PDCCH;- indication of paging resource;- indication of a carrier to use for WUS monitoring;- indication of a carrier to use for paging reception;- command to switch a WUS reception mode;- command to activate or deactivate WUR operation; an- command to switch WUR operation mode.11. A method performed by a base station, the method comprising:- any of the steps, features, or functions described above with respect to base stations, either alone or in combination with other steps, features, or functions described above.12. The method of the previous embodiment, further comprising one or more additional base station steps, features or functions described above.Group C Embodiments13. A mobile terminal comprising:- processing circuitry configured to perform any of the steps of any of the Group A embodiments; and- power supply circuitry configured to supply power to the wireless device.14. A base station comprising:- processing circuitry configured to perform any of the steps of any of the Group B embodiments;- power supply circuitry configured to supply power to the wireless device.15. A user equipment (UE) comprising:- an antenna configured to send and receive wireless signals;- radio front-end circuitry connected to the antenna and to processing circuitry, and configured to condition signals communicated between the antenna and the processing circuitry;- the processing circuitry being configured to perform any of the steps of any of the Group A embodiments;- an input interface connected to the processing circuitry and configured to allowinput of information into the UE to be processed by the processing circuitry;- an output interface connected to the processing circuitry and configured to output information from the UE that has been processed by the processing circuitry; and- a battery connected to the processing circuitry and configured to supply power to the UE.

Claims

CLAIMS1. A method (800) performed by a wireless device, the method comprising: receiving (810), from a network node, a wake up signal (WUS) comprising an on-off keyed (OOK) pattern where orthogonal frequency division multiplexing (OFDM) sequences are transmitted during ON durations of the OOK pattern, wherein first information is carried by the OOK pattern and second information is carried by the OFDM sequences, wherein the second information includes additional information not included in the first information.

2. The method of claim 1, wherein the second information further includes the first information.

3. The method of any of the preceding claims, wherein the first information indicates that the wireless device is to monitor a physical downlink control channel (PDCCH).

4. The method of any of the preceding claims, wherein the first information indicates a first group of wireless devices addressed by the WUS.

5. The method of any of the preceding claims, wherein the second information indicates a second group of wireless devices addressed by the WUS.

6. The method of any of the preceding claims, wherein the first information together with the additional information indicates a third group of wireless devices addressed by the WUS7. The method of any of the preceding claims, wherein the additional information comprises one or more of: an aggregation level for monitoring of a channel for downlink control information; a number of candidates for monitoring of a channel for downlink control information; a number of paging occasions to be monitored by the wireless device.

8. The method of any of the preceding claims, wherein the additional information comprises one or more of: a cell ID;a WUR configuration index; synchronization information; information regarding which reference signal to be used for wake up radio (WUR) based measurements and / or how often to perform WUR based measurements; information related to system information (SI) update notification; information regarding measurement relaxation for a main receiver; information regarding sleep mode of a main receiver.

9. The method of any of the preceding claims, wherein the additional information comprises one or more of:- an indication of a length of a physical downlink control channel (PDCCH) monitoring window to be applied by the wireless device;- an indication of a PDCCH search space to be used after receiving the WUS;- an indication of a downlink bandwidth part (BWP) for the wireless device to apply for monitoring paging occasions (POs) and PDCCH;- an indication of which cell groups the wireless device should be woken up to monitor PDCCH;- an indication of paging resource;- an indication of a carrier to be used for WUS monitoring;- an indication of a carrier to be used for paging reception;- a command to switch a WUS reception mode;- a command to activate or deactivate WUR operation;- a command to switch WUR operation mode between duty cycled WUR operation and continuous WUR operation or to switch to new duty-cycle parameters for WUR operation.

10. The method of any of the preceding claims, wherein the wireless device uses the additional information for error detection and / or error correction.

11. The method of any of the preceding claims, wherein the OOK pattern has equal number of ON duration as OFF durations.

12. The method of any of the preceding claims, further comprising:obtaining (820) the first information from the WUS; and / or obtaining (830) the second information from the WUS.

13. The method of any of the preceding claims, wherein the wireless device comprises a wake up receiver (WUR) capable of OFDM based signal reception.

14. The method of any of the preceding claims, further comprising: waking up (840) a main receiver based on one or more of the first information and the second information to monitor a physical downlink control channel (PDCCH).

15. The method of any of the preceding claims, wherein the wireless device uses envelope detection to obtain the first information.

16. The method of any of the preceding claims, wherein the first information is modulated on the OOK pattern and / or the second information is modulated on the OFDM sequences.

17. A method (900) performed by a network node, the method comprising: transmitting (910) a wake up signal (WUS) comprising an on-off keyed (OOK) pattern where orthogonal frequency division multiplexing (OFDM) sequences are transmitted during ON durations of the OOK pattern, wherein first information is carried by the OOK pattern and second information is carried by the OFDM sequences, wherein the second information includes additional information not included in the first information.

18. The method of claim 17, wherein the second information further includes the first information.

19. The method of any of claims 17-18, wherein the first information indicates that the wireless device is to monitor a physical downlink control channel (PDCCH).

20. The method of any claims 17-19, wherein the first information indicates a first group of wireless devices addressed by the WUS.

21. The method of any of claims 17-20, wherein the second information indicates a second group of wireless devices addressed by the WUS.

22. The method of any of claims 17-21, wherein the first information together with the additional information indicates a third group of wireless devices addressed by the WUS23. The method of any of claims 17-22, wherein the additional information comprises one or more of: an aggregation level for monitoring of a channel for downlink control information; a number of candidates for monitoring of a channel for downlink control information; a number of paging occasions to be monitored by the wireless device.

24. The method of any of claims 17-23, wherein the additional information comprises one or more of: a cell ID; a WUR configuration index; synchronization information; information regarding which reference signal to be used for wake up radio (WUR) based measurements and / or how often to perform WUR based measurements; information related to system information (SI) update notification; information regarding measurement relaxation for a main receiver; information regarding sleep mode of a main receiver.

25. The method of any of claims 17-24, wherein the additional information comprises one or more of:- an indication of a length of a physical downlink control channel (PDCCH) monitoring window to be applied by the wireless device;- an indication of a PDCCH search space to be used after receiving the WUS;- an indication of a downlink bandwidth part (BWP) for the wireless device to apply for monitoring paging occasions (POs) and PDCCH;- an indication of which cell groups the wireless device should be woken up to monitor PDCCH;- an indication of paging resource;- an indication of a carrier to be used for WUS monitoring;- an indication of a carrier to be used for paging reception;- a command to switch a WUS reception mode;- a command to activate or deactivate WUR operation;- a command to switch WUR operation mode between duty cycled WUR operation and continuous WUR operation or to switch to new duty-cycle parameters for WUR operation.

26. The method of any of claims 17-25, wherein the OOK pattern has equal number of ON duration as OFF durations.

27. The method of any of claims 17-26, wherein the first information is modulated on the OOK pattern and / or the second information is modulated on the OFDM sequences.

28. A wireless device (1300) comprising:- processing circuitry (1302) configured to perform the method of claim 1; and- power supply circuitry (1308) configured to supply power to the wireless device.

29. The wireless device of claim 28, wherein the processing circuitry is configured to perform the method of any of claims 2-16.

30. A network node (1400) comprising:- processing circuitry (1402) configured to perform the method of claim 17;- power supply circuitry (1408) configured to supply power to the network node.

31. The network node of claim 30, wherein the processing circuitry is configured to perform the method of any of claims 18-27.

32. A method (1000) performed by a wireless device, the method comprising: receiving (1010), from a network node, a synchronization signal comprising an on-off keyed (OOK) pattern where orthogonal frequency division multiplexing (OFDM) sequences are transmitted during ON durations of the OOK pattern, wherein information is carried by the OFDM sequences; and using (1020) at least part of the synchronization signal as a synchronization signal for a wake up receiver (WUR).

33. The method of claim 32, wherein using at least part of the synchronization signal as a synchronization signal for a WUR comprises: using the OOK pattern as a synchronization signal for the WUR.

34. The method of any of claims 32-33, wherein using at least part of the synchronization signal as a synchronization signal for a WUR comprises: using one or more of the OFDM sequences as a synchronization signal for the WUR.

35. The method of any of claims 32-34, wherein information is carried by the OOK pattern.

36. The method of any of claims 32-35, wherein the information carried by the ODFM sequences and / or the OOK sequence comprises one or more of: system information related to WUR operation; information related to a cell ID; additional timing information; information related to measurements, such as for example measurement modes; an indication of change in measurement mode; an indication of a switch between low power synchronization signal (LP-SS) based measurements and secondary synchronization signal (SSS) based measurements; information regarding main receiver operation; an indication whether or not a cell supports OFDM-based WUR operation.

37. The method of any of claims 32-36, further comprising: receiving (1030) the information carried by the OFDM sequences and / or the OOK sequence.

38. The method of any of claims 32-37, further comprising: receiving (1040), from the network node, a wake up signal (WUS) comprising an OOK pattern where OFDM sequences are transmitted during ON durations of the OOK pattern, wherein first information is carried by the OOK pattern in the WUS and second information is carried by the OFDM sequences in the WUS, wherein the WUS is received using the WUR.

39. A wireless device (1300) comprising:- processing circuitry (1302) configured to perform the method of claim 32; andpower supply circuitry (1308) configured to supply power to the wireless device.

40. The wireless device of claim 39, wherein the processing circuitry is configured to perform the method of any of claims 33-38.

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