Patent Description:
Systems, methods, and instrumentalities associated with wake-up signals may be provided, e.g., for power saving. The systems, methods, and instrumentalities may include interference-free wake-up signal (WUS)/ go-to-sleep signal (GOS) and/or ON/OFF keying (OOK) waveform enhancements. The systems, methods, and instrumentalities for interference-free WUS/GOS may include wake-up control signal format and content and/or user multiplexing and reference symbols for WUS/GOS signaling. The systems, methods, and instrumentalities for OOK waveform enhancements may include one or more of uniform WUS/GUS using time domain masking based OOK, OOK randomization, and/or using orthogonal frequency division multiplexing (OFDM) symbols with multiple subcarrier spacing values for OOK symbols.

Systems, methods, and instrumentalities may be provided for a wireless transmit/receive unit (WTRU) to receive a signal from a network while the WTRU is in a sleep state. The signal may be or may include an OOK signal. The OOK signal may be or may include a set of OOK symbols. The set of OOK symbols may be or may include a set of OFDM symbols. The signal may include multiple levels of information. For example, the signal may indicate a first level of information, e.g., whether to wake up a WTRU from a sleep state or maintain sleep state. The signal may indicate a second level of information, e.g., WTRU ID, group WTRU ID, information about physical downlink control channel (PDCCH) resource to monitor, and/or additional information for a WTRU and/or a group of WTRUs to perform.

The WTRU may detect a bit pattern in the signal. The WTRU may detect a bit pattern based on detecting a set of ON/OFF bits. For example, the WTRU may use energy detection to detect a set of ON/OFF bits. If the WTRU detects energy above a threshold value, the WTRU may determine that the bit corresponds to an ON bit. If the WTRU detects energy below a threshold value, the WTRU may determine that the bit corresponds to an OFF bit.

The WTRU may determine whether the bit pattern matches a configured bit pattern. The configured bit pattern may indicate to the WTRU to wake up from the sleep state. For example, the configured bit pattern may be similar to (e.g., the same as) a WUS. If the WTRU determines that the bit pattern matches the configured bit pattern, the WTRU may wake up from the sleep state. If the WTRU determines that the bit pattern does not match the configured bit pattern, the WTRU may maintain the sleep state. The bit pattern that does not match to the configured bit pattern may be correspond to (e.g., considered as) a GOS.

If the WTRU wakes up from the sleep state (e.g., in response to the bit pattern matching the configured bit pattern), the WTRU may decode a set of sequences in the signal. The WTRU may determine whether the set of sequences matches a configured sequence set. If the set of sequences matches a configured sequence set, the WTRU may perform a task (e.g., determine physical downlink control channel (PDCCH) resource to monitor) based on the configured sequence set. The set of sequences may be or may include one or more of: information of a PDCCH location, a WTRU ID, or a WTRU group ID.

The CN <NUM> shown in <FIG> may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b.

Discontinuous reception (DRX) operation may be performed. A DRX may be used, e.g., for battery savings. During a DRX, a wireless transmit/receive unit (WTRU) may skip monitoring (e.g., not monitor) a downlink (DL) control channel, such as a physical downlink control channel (PDCCH). In a radio resource control (RRC) connected mode, a WTRU may use a connected mode DRX (C-DRX). <FIG> illustrates an example of ON duration and OFF duration with a DRX cycle. A WTRU may monitor a configured PDCCH during an ON duration period, and/or the WTRU may sleep (e.g., not monitor the PDCCH) during an OFF duration. PDCCH may be used herein as a non-limiting example of a DL control channel.

A DRX cycle may be a cycle (e.g., a repetition or periodic repetition) of ON duration and OFF duration. A WTRU may monitor a PDCCH during an ON duration, and/or a WTRU may skip monitoring a (e.g., any) PDCCH during an OFF duration.

A DRX cycle may include a short DRX cycle and/or a long DRX cycle. A WTRU may use a short DRX cycle for a period of time and may use a long DRX cycle.

A DRX inactivity timer may determine or may be used to determine a time (e.g., in terms of TTI duration), for example, after a PDCCH occasion. In a PDCCH occasion, a PDCCH (e.g., a successfully decoded one) may indicate an uplink (UL) and/or DL user data transmission (e.g., an initial UL and/or DL user data transmission). A WTRU may use a DRX inactivity timer to determine when to go to an OFF duration.

A DRX ON duration may be the duration at the beginning of a DRX cycle.

A DRX ON duration timer may determine or may be used to determine a number of PDCCH occasion(s), such as a consecutive number of PDCCH occasion(s). The PDCCH occasion(s) may be or may need to be monitored and/or decoded (e.g., by a WTRU), for example, after wakeup from the DRX cycle and/or at the beginning of a DRX cycle.

A PDCCH occasion may include a time period that includes a PDCCH (e.g., a symbol, a set of symbols, a slot, and/or a subframe).

A DRX retransmission timer may determine or may be used to determine a number of PDCCH occasion(s) (e.g., a consecutive number of PDCCH occasion(s)), for example, to monitor when a WTRU expects a retransmission. A DRX retransmission timer may determine or may be used to determine a duration (e.g., a maximum duration) until a DL retransmission is received or a duration (e.g., a maximum duration) until a grant for an UL retransmission is received.

A DRX short cycle may be a DRX cycle (e.g., the first DRX cycle) that the WTRU enters after an expiration of a DRX inactivity timer. A WTRU may be in a short DRX cycle if (e.g., until) the DRX short cycle timer expires. If the DRX short cycle timer expires, the WTRU may use a long DRX cycle.

A DRX short cycle timer may determine or may be used to determine a number of subframes (e.g., a number of consecutive subframe(s)) that the WTRU may follow the short DRX cycle, for example, after the DRX inactivity timer has expired.

<FIG> illustrates an example of an ON duration and an OFF duration with a DRX cycle.

During an OFF duration, a WTRU may skip measuring or reporting a channel status information (CSI) in a subframe. The subframe may be configured to measure and/or report a CSI reporting, such as a periodic CSI reporting.

A WTRU may monitor (e.g., may need to monitor) a PDCCH or a PDCCH occasion(s) during an active time. The active time may occur during an ON duration. The active time may occur during an OFF duration. The active time may begin during an ON duration and continue during an OFF duration. The active time and the active time of a DRX cycle may be used interchangeably herein.

An active time may include a time during which one or more of the following is true: a DRX timer may be running (e.g., an ON Duration timer, an inactivity timer, a retransmission timer (e.g., in the DL and/or the UL), or a random access contention resolution timer); a scheduling request may be sent (e.g., on physical uplink control channel (PUCCH)) and/or be pending; a PDCCH indicating a different (e.g., new) transmission addressed to a cell radio network temporary identifier (C-RNTI) of a MAC entity of the WTRU may not have been received after a successful reception of a random access response for the random access preamble that was not selected by the MAC entity among contention-based random access preambles.

Wake-up signal (WUS)/go-to-sleep signal (GOS) may be used. A WUS and/or GOS may be used, for example, with a DRX operation. A WUS/GOS may be associated with one or more DRX cycles. A WUS/GOS may be transmitted and/or received (transmitted/received) prior to an associated time and/or a part of a DRX cycle, such as an associated DRX cycle.

<FIG> illustrates an example of a WUS with a DRX operation. If a WTRU receives a WUS, the WTRU may monitor a PDCCH in ON durations for one or more DRX cycles. If a WTRU receives a GOS, the WTRU may skip monitoring the PDCCH in ON durations for one or more DRX cycles and/or may stay (e.g., mantain) in a sleep mode (e.g., a deep sleep).

A system or a network may use a WUS(s) and/or a GOS(s).

An orthogonal ON/OFF keying (OOK) may be used. There may be several ways to generate OOK symbols and/or encoded coded OOK symbols. In examples, an OFDM or DFT-s-OFDM implementation may be used to generate one or more OOK symbols. <FIG> illustrates an example of an OFDM-based OOK waveform generation with Manchester Encoding. As shown in <FIG>, sequences s and <NUM> may be used to generate one or more OOK ON and OFF symbols in time domain, respectively. s may be ON symbol generator sequence. The OOK symbol duration may be a portion of (e.g., half of) the DFT-s-OFDM symbol duration.

The input of DFT-s-OFDM may be orthogonal to each other in time domain, for example, to enable detection (e.g., simple detection) at a receiver. For example, with Manchester Encoding in time, x<NUM> = (s<NUM>, <NUM>) and x<NUM> = (<NUM>, s<NUM>), s<NUM> and s<NUM> may be non-zero vectors of complex numbers with length M/<NUM>. Time domain signals may be illustrated in <FIG> illustrates an example of an OOK waveform with Manchester Encoding.

In examples, multiple OOK symbols within an OFDM symbol duration (e.g., one OFDM symbol duration) may be generated by exploiting a structure of DFT-s-OFDM. <FIG> illustrates an example OFDM-based OOK waveform generation with Manchester encoding. The inputs of DFT-s-OFDM may be (e.g., first) divided into K parts, and a sequence <MAT> may be placed into the ith corresponding part depending on the bit (e.g., bi, for i = <NUM>,<NUM>,. For example, if bi = <NUM>, the ith corresponding part at the input of DFT-s-OFDM may be set to si. If bi ≠ <NUM>, it may be <MAT>. The output of the DFT-s-OFDM may be an oversampled version of the input of the DFT-s-OFDM, e.g., with a certain pulse shape (e.g., Dirichlet sinc function without frequency domain spectral shaping (FDSS)). The sub-time unit ON and OFF symbols may be generated at the output of DFT-s-OFDM. This (e.g., simple) structure may allow an orthogonality with other subcarriers. This structure may enable an orthogonal transmission of other channels (e.g., physical downlink shared channel (PDSCH)). <FIG> illustrates an example of orthogonal OOK.

As shown in <FIG>, the first input (e.g., Mh) and/or the last input (e.g., Mt) of the DFT-s-OFDM may be set to zeros, e.g., to improve the shaping in time domain. FDSS (e.g., in addition to and/or instead of) may be utilized, e.g., to reduce a sidelobe of the Dirichlet sinc function. The energy during a CP duration may be minimized, e.g., by choosing <MAT>. Out-of-band (OOB) emission characteristics of the wake-up signal may be improved. In examples, bi for i = <NUM>,<NUM>,. , K may be set to values (e.g., certain fix values) to generate reference symbols for a channel estimation at a receiver. Multiple DFT-s-OFDM symbol(s) may be transmitted (e.g., transmitted back-to-back) for OOK sequences, such as larger OOK sequences.

<FIG> illustrates an example of time-domain characteristics of an orthogonal OOK waveform. <FIG> illustrates one or more example samples of a time domain signal at an output of an IDFT block. The samples that have energy detected (e.g., above a threshold value) may correspond to "<NUM>" bits at an input and the samples that have little or no energy (e.g., energy below a threshold value) may correspond to "<NUM>" bits at the input, e.g., as shown in <FIG>. As described herein, a WTRU may detect an ON/OFF bit (e.g., ON/OFF bit patterns), e.g., using energy detection. A WTRU may detect sequence(s) associated with the OOK waveform. <FIG> illustrates an example of frequency domain characteristics of an orthogonal OOK waveform. In <FIG> and/or <FIG>, time and/or frequency domain characteristics of an orthogonal OOK may be illustrated for a <NUM> signal. It may be assumed that the IDFT size N = <NUM> and M = <NUM> × <NUM> = <NUM>, and/or that an impulse response of the FDSS filter in time may be [<NUM><NUM><NUM>]. Mh and/or Mt may be set to Mh = <NUM> and/or Mt = <NUM>, e.g., to avoid energy during a CP duration. A Zadoff-Chu sequence of length Ms = <NUM> may be chosen (e.g., randomly chosen) for si. K = <NUM> OOK symbols may be transmitted in time domain. In <FIG>, time domain characteristics of a generated signal after CP addition may be given for b = (<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>,<NUM>). The sidelobe of the Dirichlet sinc function may be efficiently suppressed by the FDSS. The energy during the CP duration may be low (e.g., always very low since Mt = <NUM>). A good (e.g., excellent) OOB emission (e.g., illustrated in <FIG>) may be achieved. The discontinuity between the DFT-s-OFDM symbols may be low.

WUS and/or GOS may be generated. A signal may be generated to include WUS, GOS, and/or some other signals. The generated signal described herein may include one or more of the following. By generating the signal (e.g., including WUS, GOS, and/or some other signals), a WTRU may operate less than a full power if the WUS and/or GOS is demodulating. For example, a WTRU may not operate (e.g., may not be required to operate) with a full power (e.g., a part of WTRU RF and/or baseband may still be turned off) if the WUS and/or GOS are demodulating. Multiple access in time, frequency, or code domain may be allowed. An accurate synchronization may be allowed. Information (e.g., rich information) related to WTRU ID or WTRU group ID, and/or dedicated physical control channel (DPCCH) resource information during a power saving ON period, etc., may be allowed to be carried (e.g., in a signal generated to include WUS, GOS, and/or other signals as described herein).

WUS/GOS with reduced interference (e.g., interference-free WUS/GOS) may be used.

A format for wake-up control signal (WUCS) may be used.

The WUCS may include a signal that is used to control and/or configure a behavior(s) of a WTRU(s) during a power saving ON period. The WUCS may be used to control a designated WTRU (e.g., some or all WTRUs in a cell), for example, on when and/or how to wake up if the WUCS signals the WTRU to wake up. The WUCS may signal the WTRU to continue sleeping (e.g., maintain in the sleep state) and/or how long to stay in sleep (e.g., the length in time).

A WUCS frame may include one or more portions (e.g., three portions). The portions of the WUCS frame may include one or more of a synchronization signal, a WUCS information, and/or a reference signal (RS). One or more of the portions may be generated and/or represented in a time domain. One or more of the portions may be generated and/or represented in a frequency domain. In examples, portions may be generated and/or represented in a hybrid of time and frequency domains (e.g., some portion(s) generated/represented in the time domain and other portion(s) generated/represented in the frequency domain. <FIG> illustrates an example of a frame format for a WUCS. As shown in <FIG>, a frame format for a WUCS may include a SYNC, WUCS information, and a RS. The WUCS information portion shown in <FIG> may have data indicated, e.g., by the bits and/or sequences. The SYNC portion shown in <FIG> may be used for synchronization. The RS portion shown in <FIG> may be used for reference signals.

WUCS portions may be used (e.g., concatenated) in different orders. For example, the WUCS information sequence shown in <FIG> may occur before, after, and/or between SYNC sequence as shown in <FIG>. Different allocation of one or more of the portions may indicate certain information. A relative allocation between the portions (e.g., fields as shown in <FIG>) may carry certain information. The relative allocation between one or more of the portions may be predefined or be blindly detected. <FIG> illustrates examples of different options for SYNC and information subsequence. As shown in <FIG>, different orders of the SYNC sequences and information field in time may be used (e.g., to indicate certain information).

A WUCS may be generated. A WUCS or a part of the WUCS may be represented using sequences and/or symbols, for example, time domain orthogonal ON/OFF keying (OOK) sequences and/or OOK symbols. OOK sequences may include sequences of <NUM> and <NUM>. OOK symbols may indicate corresponding signals in time (e.g., by a rectangular wave). In examples, "<NUM>" may represent "OFF" symbol and "<NUM>" may represent "ON" symbol. The sequences may be denoted as {bi, i = <NUM>,. K may be the number of OOK sequences that may be used for different purposes (e.g., as described herein).

The OOK sequences and/or symbols may be further coded. For example, the OOK sequences and/or symbols may map "<NUM>" and "<NUM>" to binary sequences (e.g., another binary sequences). In Manchester encoding, bit "<NUM>" may be mapped to (<NUM><NUM>), and/or bit "<NUM>" may be mapped to (<NUM><NUM>). In examples, bit "<NUM>" and bit "<NUM>" may be mapped to different bit patterns, e.g., (<NUM><NUM><NUM><NUM><NUM><NUM>) and (<NUM><NUM><NUM><NUM><NUM>), respectively. The OOK sequences and/or symbols may be received by using a non-coherent detector, e.g., if the WTRU receiver has that capability during a sleeping duration. The non-coherent detector may include an envelope detector and/or an energy detector.

OOK sequences and/or symbols (e.g., (b<NUM>,b<NUM>,. , bK) as shown in <FIG>) may be used for synchronization by a WTRU.

OOK sequences and/or symbols may be used (e.g., used to indicate) as WTRU IDs or WTRU group IDs, e.g., if the OOK sequences and/or symbols are orthogonal to each other. OOK sequences and/or symbols may be used as WTRU IDs or WTRU group IDs, e.g., if the OOK sequences and/or symbols have a low or very low correlation among them.

OOK sequences and/or symbols may be used, e.g., if the OOK sequences and/or symbols are orthogonal to each other or have a low or very low correlation among them, to distinguish between signals. For example, OOK sequences and/or symbols may be used to distinguish between WUS and GOS if the OOK sequences and/or symbols are orthogonal to each other. OOK sequences and/or symbols may be used to distinguish between the WUS and the GOS if the OOK sequences and/or symbols have a low or very low correlation among them. OOK sequences and/or symbols may be used to distinguish any other signals that may control or signal the behavior of the WTRU in the power saving ON period if the OOK sequences and/or symbols are orthogonal to each other and/or have a low or very low correlation among them. OOK sequences and/or symbols may be used to distinguish any other signals that may control or signal the behavior of the WTRU in other power saving related mechanisms (e.g., different power saving cycles) if the OOK sequences and/or symbols are orthogonal to each other and/or have a low or very low correlation among them. A WUS symbol may be constructed with (<NUM>,<NUM>,<NUM>,<NUM>,. ,<NUM>,<NUM>) sequence (e.g., only (<NUM>,<NUM>,<NUM>,<NUM>,. ,<NUM>,<NUM>) sequence). A GOS symbol may be constructed with (<NUM>,<NUM>,<NUM>,<NUM>,. ,<NUM>,<NUM>) sequence. Hadamard codes may be used for GOS and WUS signals. The WUS symbol may be predefined. For example, (<NUM>,<NUM>,<NUM>,<NUM>,. ,<NUM>,<NUM>) sequence may indicate a WUS symbol. If the WTRU receives (<NUM>,<NUM>,<NUM>,<NUM>,. ) sequence, the WTRU may wake-up. The GOS symbol may be predefined. For example, (<NUM>,<NUM>,<NUM>,<NUM>,. ,<NUM>,<NUM>) sequence may indicate a GOS symbol. If the WTRU receives (<NUM>,<NUM>,<NUM>,<NUM>,. ,<NUM>,<NUM>) sequence, the WTRU may go to sleep. Hadamard codes described herein may be an example of a sequence that may be used for the selection of the predefined sequences.

An OOK sequence (e.g., (b<NUM>,b<NUM>,. , bK)) may include a subsequence for SYNC. The subsequence for SYNC may be predefined. An OOK sequence may include a subsequence (e.g., alone or in addition to the subsequence for SYNC) for additional wake-up and/or WTRU/WTRU group information, which may include RS(s) in time and/or frequency domain.

One or more (e.g., pre-defined) sequences may be used for SYNC, wake-up information, WTRU/WTRU group information, WTRU ID, WTRU group ID, and/or the like. The SYNC, wake-up information, WTRU/WTRU group information, WTRU ID, WTRU group ID described herein may be examples of information for the sequences and may not be limited to the SYNC, wake-up information, WTRU/WTRU group information, WTRU ID, WTRU group ID.

A SYNC (e.g., a SYNC field) and user multiplexing may be simultaneous.

A sequence of OOK symbols or a set of OOK symbols (e.g., coded or not coded) may be used for a SYNC (e.g., a SYNC field). If a set of possible OOK sequences is used for SYNC (e.g., SYNC sequences), an (e.g., each) OOK sequence may be associated with a cell ID, a WTRU group ID, or a WTRU ID, which in examples, may enable cell-wise wake-up, group wake-up, or individual wake-up, respectively.

Sequences (e.g., the sequences {si} that are used to generate "ON" symbol during an OOK sequence for the SYNC sequence) may be used to represent one or more of a cell ID, a WTRU group ID, or a WTRU ID. Some of the sequences may be used as a RS(s), e.g., for a coherent detection of the sequences {si}.

In examples, OOK symbol generation with DFT-s-OFDM may allow a coherent detection of the elements of sequences si. The sequences si may be used to carry information (e.g., information related to WTRU power saving) and/or enable simultaneous SYNC in time (e.g., as shown in <FIG>). The sequences si may be used to multiplex different WTRUs (e.g., by using different sequences) and/or enable simultaneous SYNC in time (e.g., as shown in <FIG>). A SYNC sequence(s) may be based on a cell ID. A SYNC sequence(s) may indicate a GOS and/or a WUS. For a WTRU ID, orthogonal si may be used to wake up and/or sleep intended WTRUs. Zadoff-Chu sequences may be utilized for different WTRUs, e.g., to improve a detection, such as a coherent detection of the element of sequences si. Zadoff-Chu sequences may be utilized for different WTRUs to transmit information related to WTRU IDS or WTRU group IDs. Zadoff-Chu sequences may be utilized, e.g., for different WTRUs, to transmit information related to whether a WTRU should be woken up and/or should continue to sleep during the WTRU power saving ON or OFF periods. Zadoff-Chu sequences may be utilized, e.g., for different WTRUs, to transmit information related to PDCCH allocations in time and/or frequency during a power saving ON period.

Some of sequences si may be used as a RS(s), e.g., if a coherent detection is used by a WTRU. The RSs may be inserted in a frequency domain. <FIG> illustrates an example of simultaneous SYNC transmission and WTRU multiplexing.

A WUCS information field may be used. A WUCS information field may be presented using OOK sequences. Some of the OOK sequences may represent certain information, e.g., WUS and/or GOS. The sequences {si} that are used to generate the "ON" symbol of an OOK signal (e.g., OOK waveform) may carry other information (e.g., other additional information). For example, if an OOK sequence represents "Wake up in the next Power Saving ON duration to check DPCCH," the sequences {si} that are used to generate the ON symbol(s) of the OOK waveform may carry information about the location of a PDCCH (e.g., in time-frequency resource). The sequences {si} may carry other information (e.g., cell ID, WTRU, and/or WTRU group ID). A SYNC frame may carry such information. Some of the sequences may be used as a RS(s), e.g., for some of the "ON" OOK symbol/duration.

In examples, SYNC sequences may include a plurality of OOK waveforms. The information subsequence (e.g., field) may include a plurality of OFDM symbols. The plurality of OFDM symbols may be modulated with some sequences and/or modulation symbols (e.g., quadrature phase shift keying (QPSK) as illustrated in <FIG>). A receiver may demodulate an OFDM waveform(s) to receive additional information related to a WUS, a GOS, and/or any other power saving related information, e.g., after the receiver achieves a SYNC with OOK sequences. The OFDM waveform(s) (e.g., OFDM symbol(s)) may include reference symbols and/or a sequence(s) related to WUS and/or GOS, e.g., for one or more WTRUs. The WTRUs may be multiplexed on a same subcarrier, e.g., by using orthogonal sequences. The orthogonal sequences may be generated by using a cyclic shift of a time domain signal (e.g., of unimodular sequence in frequency). The SYNC sequence may be a function of a cell ID and the WTRU ID or WTRU group ID, e.g., to decrease the interference. <FIG> illustrates an example of using OOK and OFDM transmission(s) for WUS/GOS.

One or more reference signals may be added to a WUCS(s). Additional RS(s) may be added to a WUCS(s). The RS(s) may be presented in time domain, e.g., as the input to the DFT of DFT-s-OFDM operation. The RS(s) may be presented in frequency domain, e.g., as the input to the DFT of OFDM operation. The RS(s) may be used to achieve a more coherent detection of the sequences {si} in a WUCS field.

A receiving implementation may be used. A receiving implementation may include one or more of the features illustrated in <FIG> and/or as described herein.

It may be assumed that a WUS/GOS includes SYNC and/or WTRU/WTRU group ID in a time domain OOK format. It may be assumed that a WUS/GOS includes PDCCH resource allocation information, e.g., in the sequences that are used to generate an OOK waveform. A receiving implementation (e.g., similar to the one shown in <FIG>) may be used. <FIG> illustrates an example receiving implementation at a WTRU.

OOK waveform enhancement may be performed.

OOK randomization may be used, e.g., for OOK waveform enhancement.

Sequences on different parts at an input of DFT-s-OFDM (e.g., shown in <FIG>) may be different from each other. The sequences on different parts at an input of DFT-s-OFDM may be different from each other to randomize (e.g., increase a randomness of) a signal. The sequences on different parts at an input of DFT-s-OFDM may be different from each other to avoid high power spectral density on certain tone(s) in a spectrum. For example, different roots of Zadoff-Chu sequences may be used at different parts at the input of DFT-s-OFDM. Different roots of Zadoff-Chu sequences may be chosen based on a pseudo random number, e.g., linear feedback shift register. In examples, cyclic shifted versions of a Zadoff-Chu sequence(s) may be utilized at different parts. The choice of the sequence may be a function of a WTRU index and/or a parameter(s) related to a cell ID.

OOK symbols with OFDM symbols with multiple subcarrier spacing values may be used, e.g., for OOK waveform enhancement.

In examples, OOK symbols may be generated by using OFDM symbols with a high (e.g., higher) subcarrier spacing (e.g., a shorter OFDM symbol duration), e.g., <NUM> or <NUM>. Bit "<NUM>" may be encoded with an existence of an OFDM symbol(s). A non-existence of an OFDM symbol(s) (e.g., nothing) may be transmitted for bit "<NUM>.

Uniform OOK symbols for mask-based OOK may be used, e.g., for OOK waveform enhancement.

In examples, an OOK signal may be generated by generating an OFDM symbol and (e.g., then) masking the OFDM symbol (e.g., masking the time domain OFDM signal as shown in <FIG>). The OOK signal may be further processed. For example, the OOK signal may be filtered.

A sequence y(Mx1) of length M may be loaded into a set of interleaved subcarriers, for example, in a predetermined band of a channel. For example, in an interleaved allocation, zeros may be mapped to the subcarriers that are between two subcarriers loaded with coefficients from the sequence. The number of zeros may be (L-<NUM>). L may be referred to as the interleaving factor.

The output of the IDFT may have a repetitive structure (e.g., with the type of allocation herein). The output of the IDFT may include repetitions of a time domain signal. In <FIG>, the signal that repeats itself may be denoted with a vector x. The number of repetitions of the signal may be equal to L. Vector x and sequence y may be related to IDFT, e.g., up to a scaling factor: x = IDFT(y)/L.

Some (e.g., each) of the repetitive signals may be masked to create an OOK signal. As shown in <FIG>, each x may be masked. For example, each x may be multiplied with a <NUM> (ON) or a <NUM> (OFF), creating an OOK signal. ON and OFF signals may be created by masking the OFDM symbol with other pairs of integers other than <NUM> and <NUM>.

A WTRU may detect ON and OFF bits and/or ON and OFF bit patterns, e.g., upon a reception of an OFDM signal, for example as shown in <FIG>, <FIG>, and/or <NUM>. The WTRU may detect ON and OFF bits/bit patterns which may provide a first level of information. For example, the WTRU may detect the ON and OFF bits/bit patterns, e.g., by using energy detection. If the detected energy is above a threshold (e.g., a preconfigured threshold value), the WTRU may detect an ON bit (e.g., as shown in <FIG>, <FIG>, and/or <NUM>). If the detected energy is below a threshold (e.g., a preconfigured threshold value), the WTRU may detect an OFF bit (e.g., as shown in <FIG>, <FIG>, and/or <NUM>). As shown in <FIG>, <FIG>, and/or <NUM>, the WTRU may detect the ON/OFF bit patterns, e.g., using energy detection. The bit patterns may be or may include binary digits, e.g., (<NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM><NUM>) as shown as an example in <FIG> and/or <NUM>. The detected bit pattern may carry information (e.g., a first level of information). For example, the bit pattern may be or may include an indication (e.g., a WUS) to the WTRU (e.g., and/or a group of WTRUs) to wake-up from a sleep state. The bit pattern may be or may include an indication (e.g., a GOS) to the WTRU (e.g., and/or a group of WTRUs) to maintain in the sleep state.

If the WTRU (e.g., and/or the group of WTRUs) wakes up from the sleep state, the WTRU may detect sequence(s) (e.g., where sequence(s) may refer to one or more sequences, a set of sequences, sequence sets, order of sequences, etc.), such as x and/or y as described herein or sequence(s) {si} shown in <FIG>, <FIG>, and/or <NUM>. The sequence(s) may carry information (e.g., a second level of information). For example, the sequence(s) may carry a WTRU group ID and/or a WTRU ID. The sequence(s) may include information about an upcoming PDCCH resource (e.g., location of the PDCCH). The WTRU may detect sequence(s) , such as sequences x and/or y as described herein or sequence(s) as shown in <FIG>, <FIG>, and/or <NUM>, providing a second level of information as described herein.

ON/OFF bits and sequence(s) may be used (e.g., used jointly) to transmit information to the WTRU. For example, ON/OFF bits/bit patterns may provide a first level of information (e.g., waking up a WTRU or a group of WTRUs from a sleep state or maintain a sleep state for a WTRU or a group of WTRUS). The sequence(s) (e.g., one or more sequences, a set of sequences, sequence sets, order of sequences) may provide a second level of information. For example, the sequence(s) may be or may include information about upcoming PDCCH resources, a WTRU ID, or a WTRU group ID, etc. The WTRU may decode the second level of information if the sequence(s) matches with a preconfigured pattern.

An example implementation for a WTRU or a group of WTRUs may include one of more of the following. A WTRU may receive an OFDM signal. The WTRU may detect ON/OFF bits associated with the OFDM signal, e.g., using energy detection as described herein. The WTRU may store the received OFDM signal. If the detected ON/OFF bits match with a preconfigured bit pattern, the WTRU may wake up from a sleep state. If the detected ON/OFF bits do not match with a preconfigured bit pattern, the WTRU may maintain the sleep state. As described herein, the detected ON/OFF bits may provide a first level of information. The WTRU may detect/decode sequence(s) associated with the stored OFDM signal. As described herein, the detected sequence(s) may provide a second level of information. If the sequence(s) associated with the stored OFDM signal matches with a preconfigured sequence(s), the WTRU may perform a specified action.

A WTRU may be configured to perform a first specific action if the WTRU receives a specific bit pattern of ON/OFF bits. A WTRU may be configured to perform a second specific action if the WTRU receives a specific sequence(s), e.g., sequence(s) matching a stored/preconfigured sequence(s). As shown in <FIG>, <FIG>, and/or <NUM>, the bit pattern may be a series of binary digits. As shown in <FIG>, <FIG>, and/or <NUM>, the sequence(s) may be determined based on an OFDM signal, e.g., by applying receive processing such as a DFT, an equalization, an IDFT, and/or a channel estimation.

Upon receiving an OFDM signal, a WTRU may determine a received pattern of ON/OFF bits and the received sequence(s) associated with the OFDM signal. In examples, if the received pattern of the ON/OFF bits and the received sequence(s) match with a configured pattern of ON/OFF bits and configured sequence(s), a WTRU may wake up from a sleep state. If a received pattern of the ON/OFF bits and/or a received sequence(s) associated with an OFDM signal do not match the configured pattern of ON/OFF bits and the configured sequence(s), a WTRU may continue a sleep state (e.g., maintain the sleep state) or may perform another configured action.

The ON/OFF bits may target a group of WTRUs. For example, the ON/OFF bits/bit patterns may be WTRU-group specific. The sequence(s) may be WTRU-specific. For example, if the ON/OFF bits/bit patterns match with a preconfigured ON/OFF bits/bit patterns for a WTRU group, WTRUs in the group may wake up and/or proceed to detecting the sequence(s). If the detected sequence(s) matches with a stored/preconfigured sequence(s) for a WTRU in the group of WTRUs, the WTRU in the WTRU group may wake-up, e.g., from the sleep state. In examples, the ON/OFF bit pattern may be used as a WTRU-specific indication and the sequence(s) may be configured as a WTRU-group specific indications. In examples, the ON/OFF bit pattern and the sequence(s) may be jointly used to indicate to different sets of WTRUs in the cell, e.g., to perform a specific task.

An OFDM signal may have a repetitive structure. The receiving WTRU may use a signal having a repetitive structure (e.g., an OFDM signal) for synchronization. The OFDM signal may be transmitted more than once, e.g., to improve a signal-to-interference-plus-noise ratio (SINR). For example, the OFDM signal may be repeated (e.g., at least two times) within a slot.

In examples, the sequence y may be multiplexed with a known reference signal, for example, before being mapped to a set of interleaved subcarriers. For example, the output of the multiplexer may be or may include (y<NUM>, y<NUM>, r<NUM>, y<NUM>, y<NUM>, r<NUM>,. r = [r<NUM>, r<NUM>,. , rK] may be a reference signal of length K symbols. Some (e.g., each) symbols may be or may include a QPSK modulation symbol. The output of the multiplexer may be mapped to the set of interleaved subcarriers. If an OOK signal is received (e.g., upon reception of an OOK signal), the WTRU may perform a channel estimation using the reference signal. The WTRU may use the channel estimate to detect the sequence y.

In examples, a WTRU may skip using (e.g., not to use) the information carried by a sequence if the received SINR is low (e.g., lower than a certain value). In examples, a WTRU may be configured to ignore an estimated/detected sequence and/or not attempt to estimate/detect the sequence.

In examples, y may include coded and/or modulated information bits. For example, k information bits may be encoded with a channel encoder and/or modulated with a QPSK modulation. The encoded bits may have a cycle redundancy check (CRC). The CRC may be scrambled with a specific radio network temporary identifier (RNTI). The information bits may be used to convey information to a WTRU or a group of WTRUs. For example, the information may be or may include one or more of WTRU ID, WTRU group ID, information associated with PDCCH, and/or the like. The WTRU(s) may access the information. The WTRU(s) may detect (e.g., first detect) the ON/OFF bits. If the WTRU(s) detects the ON/OFF bits, the WTRU(s) may determine to proceed further to detect the information bits. <FIG> illustrates an example of masking based OOK generation.

Beam-based OOK may be used, e.g., for OOK waveform enhancement.

A beam-based OOK signal may be generated for WUS/GOS, e.g., one or more of the following may apply. An OFDM symbol may be generated. The time domain OFDM signal may be beamformed to one or more spatial directions, for example, within a duration of a DFT-s-OFDM symbol or an OFDM symbol. <FIG> illustrates an example of a beam-based OOK generation. The example shown in <FIG> may be for WUS/GOS with a beamformer. In the example shown in <FIG>, different K parts of a DFT-s-OFDM symbol may be beamformed with K different beams.

K parts in a DFT-s-OFDM symbol may be orthogonal and/or non-overlapped in a time domain. The time length for a (e.g., each) part within the DFT-s-OFDM symbol may be the same. The time length for a (e.g., each) part within the DFT-s-OFDM symbol may be different.

The number of beams may be equal to or smaller than the number of parts. The number of parts associated with a beam may be determined, configured, and/or used based on one or more of following: k parts may be consecutive or distributed within a DFT-s-OFDM symbol (e.g., assuming that the k parts may be associated with a beam); k may be determined based on the number of Tx beams and/or Rx beams used; k may be determined based on at least one of the following: the number of Tx beams and/or Rx beams, the number of parts, and/or the number DFT-s-OFDM symbols used for a beam based OOK WUS/GOS transmission.

One or more parts associated with a beam may include at least one of following: control information (e.g., PDCCH) to be monitored associated with the beam; data information (e.g., PDSCH) associated with the beam; a beam reference signal (e.g., CSI-RS, synchronization signal block (SSB) and/or demodulation reference signal (DMRS) of PDCCH/PDSCH/ and/or SYNC, and/or RS) associated with a predefined sequence denoted as <MAT> (e.g., as described herein).

One or more parts associated with a beam may include the control information (e.g., PDCCH) to be monitored associated with the beam. A beam-specific control information may be transmitted in one or more parts associated with the beam.

One or more parts associated with a beam may include the beam reference signal (e.g., CSI-RS, SSB and/or DMRS of PDCCH/PDSCH/ and/or SYNC, and/or RS of WCSG). The beam reference signal may be associated with a predefined sequence denoted as <MAT> (e.g., as described herein). A set of sequences may be used, configured, and/or predefined. One of the sequences may be selected and/or determined based on a beam identity and/or a beam index. A WTRU may detect (e.g., blindly detect) the sequence used for the beam reference signal and/or identify the beam index. The WTRU may select and/or report a beam index (e.g., a preferred beam index), e.g., based on the measurement of beam reference signals and/or detected beam index. The preferred beam index may be, for example, the beam index that provides high (e.g., a highest) received signal strength (e.g., L1-reference signal received power (L1-RSRP), L1-reference signal received quality (L1-RSRQ), or L1-SINR).

The sequence(s) in one or more parts in a DFT-s-OFDM symbol may include beam-related information (e.g., a beam index and/or a panel identifier (ID)).

A beam reference signal (BRS) may be transmitted in one or more parts. The BRS sequence length may be determined based on the number of parts used for a beam reference signal transmission. For example, a first BRS sequence length may be used if the BRS is transmitted over K<NUM> parts and a second BRS sequence length may be used if the BRS is transmitted over K<NUM> parts. The first BRS sequence length may be shorter than the second BRS sequence length, for example, if K<NUM> < K<NUM>. A longer BRS sequence length may be used if a wider beam width is used.

An input signal s may be segmented to parts as s = [s<NUM>s<NUM> ··· sK]<NUM>×M. Each si may have same or different lengths. Each si may start and/or end with a number of zero element, for example, to allow transition from one beam to another. For example, it may be that si = [<NUM>. <NUM>σ<NUM> ··· σLi<NUM> ··· <NUM>] where σi = [σ<NUM> ··· σLi] is a non-zero vector. One or more of following may apply. The number of zero elements in a (e.g., each) part of an input signal (si) may be determined based on the number of bits transmitted in each part of the input signal. The number of zero elements in a (e.g., each) part of an input signal may be configured and/or indicated by a transmitter. No zero element may be used for a part of an input signal (si), e.g., while one or more parts of the input signals may be based on one or more (e.g., all) zero elements. For example, even-numbered part input signals may be based on one or more (e.g., all) non-zero elements. Odd-numbered part input signals may be based on one or more (e.g., all) zero elements. The odd-numbered parts may be used as a gap. Reference signal and/or data may be multiplexed within a non-zero vector σi in a (e.g., each) part of an input signal. For example, one or more non-zero elements (e.g., (σ<NUM>, σ<NUM>) may be used as a reference signal, and the rest of non-zero elements (e.g., σ<NUM>,. , σLi) may be used as data transmission (e.g., the data may be control information or unicast traffic information). In examples, vector si may be the same for K parts to assist other system functions (e.g., channel sounding, synchronization, and/or the like) and/or carrying some of system information (e.g., cell-ID, number of TX antennas, system frame number, subframe number, slot number, mini-slot number, channel or service type, etc.). In examples, vector σi may carry an identification (e.g., a unique identification) to indicate an identity of a transmitted beam to a receiver, e.g., to facilitate the beam pairing and/or beam selection process. The vector σi may carry a combination of identifications (e.g., WTRU ID, WTRU group ID, panel ID, or cell-lD, etc.) along with some common information across K parts.

As described herein, <FIG>, e.g., along with <FIG>, <FIG>, and <FIG>, illustrates an example OOK WUS using energy detection and sequence detection associated with a OFDM signal. For example, a WTRU may detect ON/OFF bits/bit patterns using energy detection (e.g., as shown in <FIG>, <FIG>, and/or <NUM>). The ON/OFF bits/bit patterns associated with the OFDM signal may provide a first level of information (e.g., as shown in <FIG> and/or <NUM>). The ON/OFF bits/bit patterns may indicate a WTRU or a group of WTRUs to wake up from a sleep state and may indicate another WTRU and/or another group of WTRUs to maintain the sleep state as described herein. If the WTRU or the group of WTRUs wake up from the sleep state, the WTRU or the group of WTRUs may detect a sequence(s) associated with the OFDM signal (e.g., as shown in <FIG> and/or <NUM>). The detected sequence(s) may include a second level of information. For example, the sequence(s) may include a group ID(s). The sequence(s) may include information about upcoming PDCCH resource information. The sequence(s) may be used as a synchronous signal and/or a reference signal.

In examples, the instrumentalities and implementations described herein may be applied to NR, e.g., in NR licensed spectrum, in NR unlicensed spectrum, and/or other scenarios.

Although the features and elements of the present invention are described in the preferred embodiments in particular combinations, each feature or element can be used alone without the other features and elements of the preferred embodiments or in various combinations with or without other features and elements of the present invention.

Claim 1:
A wireless transmit/receive unit, WTRU, (<NUM>) comprising:
a processor (<NUM>) configured to:
receive a signal from a base station while the WTRU (<NUM>) is in a sleep state, wherein the signal comprises K parts corresponding to a bit pattern of K bits, each part being a sequence and all K sequences of the signal forming a set of sequences, wherein an i-th part of the K parts corresponds to a sequence si with non-zero complex numbers if a corresponding i-th bit bi in the bit pattern is <NUM> and the i-th part of the K parts corresponds to a sequence of <NUM> if the corresponding i-th bit bi in the bit pattern is <NUM>;
detect the bit pattern indicated by the signal based on energy detection;
determine whether the bit pattern matches a configured bit pattern;
based on a determination that the bit pattern matches the configured bit pattern, wake up from the sleep state;
upon waking up from the sleep state, determine whether the set of sequences matches a configured sequence set; and
based on a determination that the set of sequences matches the configured sequence set, determine a physical downlink control channel, PDCCH, resource to monitor based on the configured sequence set.