Patent Description:
The following relates generally to wireless communications, and more specifically to multicarrier on-off keying symbol randomizer.

A wireless network, for example a WLAN, such as a Wi-Fi (i.e., Institute of Electrical and Electronics Engineers (IEEE) <NUM>) network may include a first wireless device (e.g., an access point (AP)) that may communicate with one or more second wireless devices (e.g., stations (STAs) or mobile devices). The AP may be coupled to a network, such as the Internet, and may enable a mobile device to communicate via the network (or communicate with other devices coupled to the access point). A wireless device may communicate with a network device bi-directionally. For example, in a WLAN, a wireless station (STA) may communicate with an associated AP via downlink (DL) and uplink (UL). The DL (or forward link) may refer to the communication link from the AP to the station, and the UL (or reverse link) may refer to the communication link from the station to the AP.

In some examples, information may be transmitted from one wireless device to another wireless device in a wireless communications system using on-off keying. In on-off keying, the information is indicated based on the presence or absence of a signal during each symbol. For example, the presence of the signal during a particular symbol may indicate a binary "<NUM>", while the absence of the signal during the symbol indicates a "<NUM>".

<CIT> relates to signal quality measurement for device-to-device communication, comprising measuring power of a Device-to-Device (D2D) signal used by the wireless device for D2D operation; determining a power difference between the measured power of the D2D signal and a physical Device-to-Device Synchronization Signal (D2DSS); estimating power of a D2DSS using the measured power of the D2D signal and the determined power difference; and performing a D2D operation using the estimated power of the D2DSS.

The document "<NPL>, relates to On Symbold generation of <NUM> MC-OOK 'On' Symbols and <NUM> MC-OOK 'On' Symbols in wireless communications.

The described techniques relate to improved methods, systems, devices, or apparatuses that support multicarrier on-off keying symbol randomizer. Generally, the described techniques provide for randomizing modulation symbol waveforms over an on-off keying sequence. A first wireless device (e.g., an access point (AP)) may identify a sequence of on symbols and off symbols for transmission to a wake-up radio (WUR) of a second wireless device. The AP may assign a modulation symbol from a set of possible modulation symbol waveforms to at least each on symbol in the sequence. The modulation symbol waveforms may be assigned to sequential on symbols in a random or pseudorandom order, e.g., by applying a random phase rotation to a stored modulation symbol waveform for each on symbol, by applying a random cyclic shift to a stored modulation symbol waveform for each on symbol, or by applying a random or pseudorandom phase-shift keying value to each subcarrier in a multicarrier system to generate a modulation symbol waveform for each on symbol. The AP may transmit the sequence to the WUR based at least in part on the assigned modulation symbol waveforms.

On-off keying may be used for transmitting information in a wireless communications system. Because the information is indicated by the presence or absence of a waveform during a particular symbol, the exact structure of the waveform itself may be irrelevant to whether the receiving device understands the message. As such, some wireless devices may use a single waveform for each on symbol.

However, when the same waveform is used for each on symbol, the waveform may have strong autocorrelation values at the spacing of the symbol duration, or of multiples thereof. Such autocorrelation may lead to spectral lines in the power spectral density, which can in turn lead to significant power in a narrow bandwidth. The use of such high power in a narrow bandwidth may pose regulatory issues, because some regulators have limits on the amount of power within a narrow bandwidth.

In order to avoid such regulatory issues, a wireless device (e.g., an access point (AP)) may assign modulation symbol waveforms from a set of possible modulation symbol waveforms to at least each on symbol in the sequence. The modulation symbol waveforms may be assigned to sequential on symbols in a random or pseudorandom order such that autocorrelation may be mitigated.

In some examples, the wireless device may assign modulation symbol waveforms from a set of possible modulation symbol waveforms by applying a random or pseudorandom phase rotation to a stored modulation symbol waveform. In some other examples, the wireless device may assign modulation symbol waveforms from a set of possible modulation symbol waveforms by applying a random or pseudorandom cyclic shift to a stored modulation symbol waveform. The random or pseudorandom phase rotation or cyclic shift may be determined based at least in part on a random or pseudorandom number (e.g., a random or pseudorandom bit or string of bits). The random or pseudorandom number may be generated by a random number generator (e.g., a linear feedback shift register).

In some examples, the wireless device may assign modulation symbol waveforms from a set of possible modulation symbol waveforms by applying a random or pseudorandom phase-shift keying value to each of a plurality of subcarriers of a multicarrier system. The resulting modulation symbol waveform may be used for the on symbol. In some examples, the modulation symbol waveform may be an orthogonal frequency division multiplexing (OFDM) symbol waveform, and the random or pseudorandom phase-shift keying value may be a binary phase-shift keying (BPSK) value or a quadrature phase-shift keying (QPSK) value.

Aspects of the disclosure are initially described in the context of a wireless communications system. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to multicarrier on-off keying symbol randomizer.

<FIG> illustrates a wireless communications system <NUM> (also known as a Wi-Fi network) configured in accordance with various aspects of the present disclosure. The wireless communications system <NUM> (e.g. wireless local area network (WLAN)). may include a first wireless device (e.g., an AP <NUM>) and multiple associated wireless devices (e.g., stations (STAs) <NUM>, which may represent devices such as mobile stations, personal digital assistant (PDAs), other handheld devices, netbooks, notebook computers, tablet computers, laptops, display devices (e.g., TVs, computer monitors, etc.), printers, etc. The AP <NUM> and the associated stations <NUM> may represent a basic service set (BSS) or an extended service set (ESS). The various STAs <NUM> in the network are able to communicate with one another through the AP <NUM>. Also shown is a coverage area <NUM> of the AP <NUM>, which may represent a basic service area (BSA) of the wireless communications system <NUM>. An extended network station (not shown) associated with the wireless communications system <NUM> may be connected to a wired or wireless distribution system that may allow multiple APs <NUM> to be connected in an ESS.

The AP <NUM> may include a communications manager <NUM>, which may randomize modulation symbol waveforms over an on-off keying sequence. The communications manager <NUM> may identify a multicarrier sequence of on symbols and off symbols for transmission to a wake-up radio (WUR) of a STA <NUM>. In some examples, the sequence of on symbols and off symbols may be defined by a technical specification and stored at the AP <NUM>.

The communications manager <NUM> may assign a modulation symbol waveform from a set of possible modulation symbol waveforms to at least each on symbol (e.g., to each on symbol, or each symbol regardless of whether it is an on symbol or off symbol), in the sequence of on symbols and off symbols. The modulation symbol waveforms may be assigned to sequential symbols (e.g., on symbols, or all symbols) in a random or pseudorandom order.

The communications manager <NUM> may assigned modulation symbol waveforms to symbols in a random or pseudorandom order by randomly or pseudorandomly selecting a modulation symbol waveform from the set of possible modulation symbol waveforms for each symbol. In some examples, the communications manager <NUM> may select a random or pseudorandom phase rotation or cyclic shift for each symbol, and may apply the random or pseudorandom phase rotation or cyclic shift to a stored modulation symbol waveform to generate the modulation symbol waveform for the symbol. In some other examples, the communications manager <NUM> may select a random or pseudorandom phase-shift keying value for each subcarrier in a multicarrier system for each symbol, may generate the modulation symbol waveform for the symbol by using the randomly or pseudorandomly selected phase-shift keying values. The phase-shift keying values may be, for example, binary phase-shift keying (BPSK) values or quadrature phase-shift keying (QPSK) values.

In some examples, the random or pseudorandom phase rotation, cyclic shift, or phase-shift keying values may be selected based at least in part on a random or pseudorandom number (e.g., a random or pseudorandom bit or string of bits). In some examples, the random or pseudorandom number may be generated by a random number generator (e.g., a linear feedback shift register). The random number generator may be initialized with a seed, which may be a fixed seed or a variable seed (e.g., a random or pseudorandom seed). In some examples, the communications manager <NUM> may cause the AP <NUM> to transmit the seed to the STA <NUM>. In some other examples, random or pseudorandom number may be determined based at least in part on a stored random or pseudorandom number.

The communications manager <NUM> may generate a transmission sequence based at least in part on the sequence of on symbols and off symbols. The transmission sequence may indicate no transmission is to be made during the off symbols, and may indicate that a corresponding assigned modulation symbol waveform is to be transmitted during each on symbol. The communications manager <NUM> may cause the AP <NUM> to transmit in accordance with the transmission sequence.

Although not shown in <FIG>, a STA <NUM> may be located in the intersection of more than one coverage area <NUM> and may associate with more than one AP <NUM>. A single AP <NUM> and an associated set of STAs <NUM> may be referred to as a BSS. An ESS is a set of connected BSSs. A distribution system (not shown) may be used to connect APs <NUM> in an ESS. In some cases, the coverage area <NUM> of an AP <NUM> may be divided into sectors (also not shown). The wireless communications system <NUM> may include APs <NUM> of different types (e.g., metropolitan area, home network, etc.), with varying and overlapping coverage areas <NUM>. Two STAs <NUM> may also communicate directly via a direct wireless link <NUM> regardless of whether both STAs <NUM> are in the same coverage area <NUM>. Examples of direct wireless links <NUM> may include Wi-Fi Direct connections, Wi-Fi Tunneled Direct Link Setup (TDLS) links, and other group connections. STAs <NUM> and APs <NUM> may communicate according to the WLAN radio and baseband protocol for physical and media access control (MAC) layers from IEEE <NUM> and versions including, but not limited to, <NUM>. 11b, <NUM>, <NUM>. 11a, <NUM>. 11n, <NUM>. 11ac, <NUM>. 11ad, <NUM>. 11ah, <NUM>. 11ax, etc. In other implementations, peer-to-peer connections or ad hoc networks may be implemented within wireless communications system <NUM>.

In some cases, a STA <NUM> (or an AP <NUM>) may be detectable by a central AP <NUM>, but not by other STAs <NUM> in the coverage area <NUM> of the central AP <NUM>. For example, one STA <NUM> may be at one end of the coverage area <NUM> of the central AP <NUM> while another STA <NUM> may be at the other end. Thus, both STAs <NUM> may communicate with the AP <NUM>, but may not receive the transmissions of the other. This may result in colliding transmissions for the two STAs <NUM> in a contention based environment (e.g., CSMA/CA) because the STAs <NUM> may not refrain from transmitting on top of each other. A STA <NUM> whose transmissions are not identifiable, but that is within the same coverage area <NUM> may be known as a hidden node. CSMA/CA may be supplemented by the exchange of a request to send (RTS) packet transmitted by a sending STA <NUM> (or AP <NUM>) and a clear to send (CTS) packet transmitted by the receiving STA <NUM> (or AP <NUM>). This may alert other devices within range of the sender and receiver not to transmit for the duration of the primary transmission. Thus, RTS/CTS may help mitigate a hidden node problem.

<FIG> illustrates an example of a wireless communications system <NUM> that supports multicarrier on-off keying symbol randomizer in accordance with aspects of the present disclosure. In some examples, wireless communications system <NUM> may implement aspects of wireless communications system <NUM>.

The wireless communications system <NUM> may include an AP <NUM> and a wireless station (STA) <NUM>. The AP <NUM> may be an example of aspects of AP <NUM> described with reference to <FIG>, and the STA <NUM> may be an example of aspects of STA <NUM> described with reference to <FIG>.

The STA <NUM> may have an active communication mode, during which the STA <NUM> actively exchanges messages with other devices (e.g., the AP <NUM>), and an idle communication mode, during which the STA <NUM> does not actively exchange messages with other devices. During the idle communication mode, the STA <NUM> may listen to communications on the wireless communications medium in case another wireless device (e.g., the AP <NUM>) has information to transmit to the STA <NUM>, in which case the STA <NUM> may transition to active communication mode. However, the use of the main radio in idle mode may result in significant energy waste. In some examples, the STA <NUM> may include a WUR which may consume less power than the main radio. The STA <NUM> may use to WUR during idle mode to decrease energy consumption in idle mode.

Because the WUR of the STA <NUM> uses low amounts of power, the indication that the STA <NUM> should switch to active communication mode may be simple. In some examples, the AP <NUM> may use on-off keying to indicate that the STA <NUM> should switch to active communication mode.

The AP <NUM> may identify a sequence of on symbols and off symbols for transmission to the WUR of the STA <NUM>. The on-off key sequence may be a multicarrier on-off sequence. In some examples, the on-off key sequence may be defined in a technical specification and stored at the AP <NUM>.

The AP <NUM> may then assign a modulation symbol waveform from a set of possible modulation symbol waveforms to at least each on symbol in the sequence of on symbols and off symbols. The modulation symbol waveforms may be assigned to sequential on symbols in a random or pseudorandom order. In some examples, the modulation symbol waveforms may also be assigned to off symbols. The modulation symbol waveforms may be assigned to sequential on symbols by randomly or pseudorandomly selecting one of the possible modulation symbol waveforms for at least each on symbol.

In some examples, the set of possible modulation symbol waveforms may consist of a stored modulation symbol waveform with one of N possible phase rotations. The modulation symbol waveform for a symbol may be assigned by applying a random or pseudorandom phase rotation to the stored modulation symbol.

In some examples, the set of possible modulation symbol waveforms may consist of a stored modulation symbols waveform with one of N possible cyclic shift values. In accordance with the present invention, the modulation symbol waveform for a symbol is assigned by applying a random or pseudorandom cyclic shift to the stored modulation symbol.

In some examples, the set of possible modulation symbols may consist of a set of NxM modulation symbol waveforms, where N is the number of possible phase-shift keying values and M is the number of subcarriers in the multicarrier system. The modulation symbol waveform for a symbol may be assigned by generating a random or pseudorandom phase-shift keying value for each of the M subcarriers. The phase-shift keying value may be, for example, a binary phase-shift keying (BPSK) value or a quadrature phase-shift keying (QPSK) value, and the resulting modulation symbol waveform may be an orthogonal frequency division multiplexing (OFDM) modulation symbol waveform.

In some examples, the random or pseudorandom phase rotation, cyclic shift, or phase-shift keying value may be determined based at least in part on a random or pseudorandom number (e.g., a random or pseudorandom bit or string of bits). In some examples, in accordance with the present invention, the random or pseudorandom number is determined based at least in part on a random number generator (e.g., a linear feedback shift register). The random number generator is initialized with a seed, which may be a fixed seed or a variable (e.g., random or pseudorandom) seed. In some examples, in accordance with the present invention, the AP <NUM> transmits the seed (e.g., the variable seed) to the STA <NUM>. When the STA <NUM> is a coherent receiver, the STA <NUM> may use the received seed to compensate at the receiver for the random or pseudorandom assignments (e.g., the random or pseudorandom phase rotation or cyclic shift). In some other examples, the random or pseudorandom number may be determined based at least in part on a stored random or pseudorandom number. For example, a linear feedback shift register may generate a pseudorandom string of bits that repeats every <NUM> bits. Instead of using the linear feedback shift register, the AP <NUM> may instead store a random or pseudorandom string of bits (which may have more than <NUM> bits).

The AP <NUM> may transmit the sequence of on symbols and off symbols to the WUR of the STA <NUM> using multicarrier on-off keying (MC-OOK). The transmitted sequence may be based at least in part on the assigned modulation symbol waveforms. For example, the AP <NUM> may transmit the corresponding assigned modulation symbol waveform during each on symbol.

<FIG> illustrates an example of a communication flow <NUM> in a wireless communications system that supports multicarrier on-off keying symbol randomizer in accordance with aspects of the present disclosure. In some examples, communication flow <NUM> may implement aspects of wireless communications system <NUM>.

The communication flow <NUM> shows communications between an AP <NUM> and a STA <NUM>. The AP <NUM> may be an example of aspects of AP <NUM> as described with reference to <FIG>. The STA <NUM> may be an example of aspects of STA <NUM> as described with reference to <FIG>.

The AP <NUM> may identify an on-off key sequence at <NUM>. The on-off key sequence may be a multicarrier on-off sequence. The on-off key sequence may include a plurality of on symbols and a plurality of off symbols. In some examples, the on-off key sequence may be defined in a technical specification and stored at the AP <NUM> (e.g., in a memory).

The AP <NUM> may randomly or pseudorandomly assign modulation symbol waveforms to on symbols of the on-off key sequence at <NUM>. In some examples, the AP <NUM> may randomly or pseudorandomly assign modulation symbol waveforms to on symbols only. In some other examples, the AP <NUM> may randomly or pseudorandomly assign modulation symbol waveforms to the entire on-off key sequence, including the off symbols.

In some examples, the AP <NUM> may randomly or pseudorandomly assign a modulation symbol waveform to a symbol (e.g., an on symbol) based at least in part on a stored symbol. A random or pseudorandom change may be applied to the stored symbol to generate the modulation symbol waveform.

In some examples, the AP <NUM> may randomly or pseudorandomly assign a modulation symbol waveform to a symbol (e.g., an on symbol) by applying a random phase rotation to a stored symbol. In some examples, the AP <NUM> may randomly or pseudorandomly assign a modulation symbol waveform to a symbol (e.g., an on symbol) by applying a random cyclic shift to a stored symbol.

In some examples, the random phase rotation or cyclic shift may be determined based at least in part on a random or pseudorandom number (e.g., a bit or string of bits). The random or pseudorandom bit or string of bits may be generated by a random number generator such as a linear phase shift register. The linear phase shift register may be initialized based at least in part on a seed number. In some examples, the seed number may be a fixed value (e.g., a value specified in a technical standard). In some other examples, the seed number may vary (e.g., randomly or pseudorandomly). In such examples, the AP <NUM> may transmit the seed to the STA <NUM>. If the STA <NUM> is a coherent receiver, the STA <NUM> may use the received seed value in compensating for the random or pseudorandom phase rotation or cyclic shift. In some other examples, the random or pseudorandom bit or string of bits may be determined based at least in part on a random or pseudorandom number (string of bits).

In some other examples, AP <NUM> may randomly or pseudorandomly assign a modulation symbol waveform to a symbol (e.g., an on symbol) without reference to a stored symbol. For example, the AP <NUM> may generate a symbol by applying a random or pseudorandom phase shift keying value to each subcarrier in a multicarrier system. The generated symbol may be an orthogonal frequency division multiplexing (OFDM) symbol, and the phase shift keying value may be a binary phase-shift keying (BPSK) value or a quadrature phase-shift keying (QPSK) value. The random or pseudorandom phase-shift keying value may be determined based at least in part on a random or pseudorandom number (e.g., a bit or string of bits). The random or pseudorandom bit or string of bits may be generated by a random number generator such as a linear phase shift register. The linear phase shift register may be initialized based at least in part on a seed number. In some examples, the seed number may be a fixed value (e.g., a value specified in a technical standard). In some other examples, the seed number may vary (e.g., randomly or pseudorandomly). In such examples, the AP <NUM> may transmit the seed to the STA <NUM>. If the STA <NUM> is a coherent receiver, the STA <NUM> may use the received seed value in compensating for the random or pseudorandom phase-shift keying values. In some other examples, the random or pseudorandom bit or string of bits may be determined based at least in part on a random or pseudorandom number (e.g., string of bits).

The AP <NUM> may transmit the on-off key sequence <NUM> to the STA <NUM>. The on-off key sequence <NUM> may be based at least in part on the modulation symbol waveforms randomly or pseudorandomly assigned to at least each on symbol.

The AP <NUM> may determine a random or pseudorandom phase rotation for at least each on symbol at <NUM>. The random or pseudorandom phase rotation may be determined based at least in part on a random number (e.g., bit or string of bits). In some examples, the random or pseudorandom number may be generated by a random number generator such as random number generator <NUM> described with reference to <FIG>. In some other examples, the random or pseudorandom number may be determined based at least in part on a stored random or pseudorandom number, which may be stored at the AP <NUM> (e.g., in a memory).

In some examples, the AP <NUM> may determine the phase rotation based at least in part on a single random or pseudorandom bit (e.g., <NUM> or <NUM>). For example, the AP <NUM> may determine a phase rotation of <NUM> degrees when the single bit is <NUM>, and may determine a phase rotation of <NUM> degrees when the single bit is <NUM>.

In some other examples, the AP <NUM> may determine the phase rotation based at least in part on a string of two random or pseudorandom bits (e.g., <NUM>, <NUM>, <NUM>, <NUM>). For example, the AP may determine a phase rotation of <NUM> degree when the string is <NUM>, may determine a phase rotation of <NUM> degrees when the string is <NUM>, may determine a phase rotation of <NUM> degrees when the string is <NUM>, and may determine a phase rotation of <NUM> degrees when the string is <NUM>.

In some other examples, the AP <NUM> may determine the phase rotation based at least in part on a string of three or more random or pseudorandom bits. For example, the phase rotations corresponding to a three-bit string are shown in Table <NUM>. Other mappings and greater numbers of bits may also be used in connection with the disclosed subject matter.

The AP <NUM> may apply the random or pseudorandom phase rotation to a stored waveform at <NUM>. In some examples, a single stored waveform may be used for each symbol. Applying the random or pseudorandom phase rotation may correspond to randomly or pseudorandomly assigning a modulation symbol waveform from a set of candidate modulation symbol waveforms. For example, when a two-bit string is used to select the phase rotation, and the phase rotation is applied to a single stored waveform, applying the phase rotation is equivalent to randomly or pseudorandomly selecting one of four possible modulation symbol waveforms to at least each on symbol.

The AP <NUM> may transmit the on-off key sequence <NUM> to the STA <NUM>. The on-off key sequence <NUM> may be based at least in part on the modulation symbol waveforms randomly or pseudorandomly assigned to at least each on symbol (e.g., based at least in part on the random or pseudorandom phase rotation applied to at least each on symbol).

<FIG> illustrates an example of a random number generator <NUM> in a wireless communications system that supports multicarrier on-off keying symbol randomizer in accordance with aspects of the present disclosure. In some examples, random number generator <NUM> may implement aspects of wireless communications system <NUM>.

The random number generator <NUM> may be a linear feedback shift register, which may be a linear feedback shift register as defined in the <NUM>. 11ba amendment to the Institute of Electrical and Electronics Engineers (IEEE) <NUM>-<NUM> standard. The random number generator <NUM> may generate a pseudorandom sequence of bits that repeats every <NUM> bits. The random number generator <NUM> may be a component of a transmitting device, which may be an example of aspects of AP <NUM> described with reference to <FIG>.

The random number generator <NUM> may include a register of seven bits. The seven bits may be divided into a first register <NUM> of three bits and a second register <NUM> of four bits. The pseudorandom sequence generated by the random number generator <NUM> may depend on the initial value of the bits in the first register <NUM> and the second register <NUM>. The random number generator <NUM> may be initialized with a seed X<NUM>X<NUM>X<NUM>X<NUM>X<NUM>X<NUM>X<NUM>. In some examples, the seed may be a fixed seed (e.g., may be specified in a technical standard). In some other examples, a variable seed (e.g., a random or pseudorandom seed) may be used to initialize the random number generator <NUM>. In such examples, the variable seed may be transmitted to a receiving device, which may be an example of aspects of STA <NUM> as described with reference to <FIG>. The receiving device may be a coherent receiver.

<FIG> illustrates an example of power spectral density measurements <NUM> at a high data rate in a wireless communications system that supports multicarrier on-off keying symbol randomizer in accordance with aspects of the present disclosure. In some examples, the wireless communications system may implement aspects of wireless communications system <NUM>.

The power spectral density measurements <NUM> include a first graph <NUM> of power spectral density measurements at a low data rate and a second graph <NUM> of power spectral density measurements at a low data rate.

The first graph <NUM> shows power spectral density measurements versus frequency when a same waveform is used for each on symbol in an on-off key sequence. The first graph <NUM> shows a number of power spectral lines in the power spectral density, which can result in significant power in a narrow bandwidth. The second graph <NUM> shows power spectral density versus frequency when a random or pseudorandom phase rotation is applied to each on symbol. The second graph <NUM> does not show power spectral lines, which indicates that the power in narrow bandwidths may be narrowed and problems associated with high narrowband power may be mitigated.

Table <NUM> shows the calculated maximum power in any <NUM> window as compared to total power, and the maximum power in any <NUM> window if the total transmission power is <NUM> dBm. As shown in Table <NUM>, in one example, the use of a same waveform leads to a maximum power in any <NUM> window relative to the total power as -<NUM> dB. When the total transmit power is <NUM> dBm, the maximum power in any <NUM> window is <NUM> dBm. This exceeds the limit of <NUM> dBm in any <NUM> window set by the Federal Communications Commission (FCC). In contrast, in one example, the use of waveforms with random or pseudorandom waveforms leads to a maximum power in any <NUM> window relative to the total power as -<NUM> dB. When the total transmit power is <NUM> dBm, the maximum power in any <NUM> window is <NUM> dBm, which satisfies the FCC requirement.

<FIG> illustrates an example of power spectral density measurements <NUM> at a low data rate in a wireless communications system that supports multicarrier on-off keying symbol randomizer in accordance with aspects of the present disclosure. In some examples, the wireless communications system may implement aspects of wireless communications system <NUM>.

The power spectral density measurements <NUM> include a first graph <NUM> of power spectral density measurements at a high data rate and a second graph <NUM> of power spectral density measurements at a high data rate.

Table <NUM> shows the calculated maximum power in any <NUM> window as compared to total power, and the maximum power in any <NUM> window if the total transmission power is <NUM> dBm. As shown in Table <NUM>, in one example, the use of a same waveform leads to a maximum power in any <NUM> window relative to the total power as -<NUM> dB. When the total transmit power is <NUM> dBm, the maximum power in any <NUM> window is <NUM> dBm. This exceeds the limit of <NUM> dBm in any <NUM> window set by the FCC. In contrast, in one example, the use of waveforms with random or pseudorandom waveforms leads to a maximum power in any <NUM> window relative to the total power as -<NUM> dB. When the total transmit power is <NUM> dBm, the maximum power in any <NUM> window is <NUM> dBm, which satisfies the FCC requirement.

<FIG> shows a block diagram <NUM> of a device <NUM> that supports multicarrier on-off keying symbol randomizer in accordance with aspects of the present disclosure. The device <NUM> may be an example of aspects of an AP as described herein. The device <NUM> may include a receiver <NUM>, a communications manager <NUM>, and a transmitter <NUM>. The device <NUM> may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses). In some examples, communications manager <NUM> may be implemented by a wireless modem. Communications manager <NUM> may communicate with transmitter <NUM> via a first interface. Communications manager <NUM> may output signals for transmission via the first interface. In some examples, communications manager <NUM> may obtain signals received by receiver <NUM> from another wireless device via a second interface.

The receiver <NUM> may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to multicarrier on-off keying symbol randomizer, etc.). Information may be passed on to other components of the device. The receiver <NUM> may be an example of aspects of the transceiver <NUM> described with reference to <FIG>. The receiver <NUM> may utilize a single antenna or a set of antennas.

The communications manager <NUM> may identify, by an AP, a sequence of on symbols and off symbols for transmission to a WUR of a wireless device, assign a modulation symbol waveform from a set of possible modulation symbol waveforms to at least each on symbol in the sequence, where the modulation symbol waveforms are assigned to sequential on symbols in a random or pseudorandom order, and transmit the sequence to the WUR of the wireless device using multi-carrier on-off keying (MC-OOK) based on the assigned modulation symbol waveforms. The communications manager <NUM> may be an example of aspects of the communications manager <NUM> described herein.

The transmitter <NUM> may transmit signals generated by other components of the device.

<FIG> shows a block diagram <NUM> of a device <NUM> that supports multicarrier on-off keying symbol randomizer in accordance with aspects of the present disclosure. The device <NUM> may be an example of aspects of a device <NUM> or an STA <NUM> as described herein. The device <NUM> may include a receiver <NUM>, a communications manager <NUM>, and a transmitter <NUM>. The device <NUM> may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses).

The communications manager <NUM> may be an example of aspects of the communications manager <NUM> as described herein. The communications manager <NUM> may include an on-off sequence identifier <NUM>, a modulation symbol waveform assigner <NUM>, and a sequence scheduler <NUM>. The communications manager <NUM> may be an example of aspects of the communications manager <NUM> described herein.

The on-off sequence identifier <NUM> may identify, by an AP, a sequence of on symbols and off symbols for transmission to a WUR of a wireless device.

The modulation symbol waveform assigner <NUM> may assign a modulation symbol waveform from a set of possible modulation symbol waveforms to at least each on symbol in the sequence, where the modulation symbol waveforms are assigned to sequential on symbols in a random or pseudorandom order.

The sequence scheduler <NUM> may transmit the sequence to the WUR of the wireless device using multi-carrier on-off keying (MC-OOK) based on the assigned modulation symbol waveforms.

<FIG> shows a block diagram <NUM> of a communications manager <NUM> that supports multicarrier on-off keying symbol randomizer in accordance with aspects of the present disclosure. The communications manager <NUM> may be an example of aspects of a communications manager <NUM>, a communications manager <NUM>, or a communications manager <NUM> described herein. The communications manager <NUM> may include an on-off sequence identifier <NUM>, a modulation symbol waveform assigner <NUM>, a sequence scheduler <NUM>, a phase rotation application unit <NUM>, a random number generator <NUM>, a seed transmission unit <NUM>, a cyclic shift application unit <NUM>, and a phase shift key (PSK) application unit <NUM>. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

In some examples, the modulation symbol waveform assigner <NUM> may assign a modulation symbol waveform from a set of possible modulation symbol waveforms to each off symbol in the sequence, where the modulation symbol waveforms are assigned to sequential symbols in the sequence in a random or pseudorandom order.

The phase rotation application unit <NUM> may apply a random or pseudorandom phase rotation to a stored modulation symbol waveform. In some examples, the phase rotation application unit <NUM> may determine the random or pseudorandom phase rotation based on a random number generator. In some examples, the phase rotation application unit <NUM> may determine the random or pseudorandom phase rotation based on a stored random or pseudorandom number sequence.

The random number generator <NUM> may initialize the linear feedback shift register with a fixed seed. In some examples, the random number generator <NUM> may initialize the linear feedback shift register with a random or pseudorandom seed.

In some cases, the random or pseudorandom number generator includes a linear feedback shift register.

The seed transmission unit <NUM> may transmit the random or pseudorandom seed to the wireless device.

The cyclic shift application unit <NUM> may apply a random or pseudorandom cyclic shift to a stored modulation symbol waveform.

The PSK application unit <NUM> may apply a random or pseudorandom phase-shift keying value to each of a set of subcarriers of a multicarrier system to generate the modulation symbol waveform.

In some cases, the modulation symbol waveform includes an orthogonal frequency division multiplexing symbol waveform.

In some cases, the random or pseudorandom phase-shift keying value includes one of a binary phase-shift keying value and a quadrature phase-shift keying value.

<FIG> shows a diagram of a system <NUM> including a device <NUM> that supports multicarrier on-off keying symbol randomizer in accordance with aspects of the present disclosure. The device <NUM> may be an example of or include the components of device <NUM>, device <NUM>, or an AP as described herein. The device <NUM> may include components for bidirectional voice and data communications including components for transmitting and receiving communications, including a communications manager <NUM>, a network communications manager <NUM>, a transceiver <NUM>, an antenna <NUM>, memory <NUM>, a processor <NUM>, and an inter-station communications manager <NUM>. These components may be in electronic communication via one or more buses (e.g., bus <NUM>).

The communications manager <NUM> may identify, by an AP, a sequence of on symbols and off symbols for transmission to a WUR of a wireless device, assign a modulation symbol waveform from a set of possible modulation symbol waveforms to at least each on symbol in the sequence, where the modulation symbol waveforms are assigned to sequential on symbols in a random or pseudorandom order, and transmit the sequence to the WUR of the wireless device using multi-carrier on-off keying (MC-OOK) based on the assigned modulation symbol waveforms.

For example, the network communications manager <NUM> may manage the transfer of data communications for client devices, such as one or more STAs <NUM>.

The memory <NUM> may include random access memory (RAM) and read only memory (ROM). The memory <NUM> may store computer-readable, computer-executable code <NUM><NUM> including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory <NUM> may contain, among other things, a basic input output system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor <NUM> may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof). In some cases, the processor <NUM> may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into processor <NUM>. The processor <NUM> may be configured to execute computer-readable instructions stored in a memory to perform various functions (e.g., functions or tasks supporting multicarrier on-off keying symbol randomizer).

The inter-station communications manager <NUM> may manage communications with other APs <NUM>, and may include a controller or scheduler for controlling communications with STAs <NUM> in cooperation with other APs <NUM>. For example, the inter-station communications manager <NUM> may coordinate scheduling for transmissions to STAs <NUM> for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager <NUM> may provide an X2 interface within a LTE/LTE-A wireless communication network technology to provide communication between APs <NUM>.

<FIG> shows a flowchart illustrating a method <NUM> that supports multicarrier on-off keying symbol randomizer in accordance with aspects of the present disclosure. The operations of method <NUM> may be implemented by an AP or its components as described herein. For example, the operations of method <NUM> may be performed by a communications manager as described with reference to <FIG>. In some examples, an AP may execute a set of instructions to control the functional elements of the AP to perform the functions described below. Additionally, or alternatively, an AP may perform aspects of the functions described below using special-purpose hardware.

At <NUM>, the AP may identify, by an AP, a sequence of on symbols and off symbols for transmission to a WUR of a wireless device. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by an on-off sequence identifier as described with reference to <FIG>.

At <NUM>, the AP may assign a modulation symbol waveform from a set of possible modulation symbol waveforms to at least each on symbol in the sequence, where the modulation symbol waveforms are assigned to sequential on symbols in a random or pseudorandom order. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by a modulation symbol waveform assigner as described with reference to <FIG>.

At <NUM>, the AP may transmit the sequence to the WUR of the wireless device using multi-carrier on-off keying (MC-OOK) based on the assigned modulation symbol waveforms. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by a sequence scheduler as described with reference to <FIG>.

At <NUM>, the AP may determine the random or pseudorandom phase rotation based on a random number generator. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by a phase rotation application unit as described with reference to <FIG>.

At <NUM>, the AP may apply a random or pseudorandom phase rotation to a stored modulation symbol waveform. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by a phase rotation application unit as described with reference to <FIG>.

At <NUM>, the AP may assign a modulation symbol waveform from a set of possible modulation symbol waveforms to each off symbol in the sequence, where the modulation symbol waveforms are assigned to sequential symbols in the sequence in a random or pseudorandom order. The operations of <NUM> may be performed according to the methods described herein. In some examples, aspects of the operations of <NUM> may be performed by a modulation symbol waveform assigner as described with reference to <FIG>.

The terms "system" and "network" are often used interchangeably. A code division multiple access (CDMA) system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers IS-<NUM>, IS-<NUM>, and IS-<NUM> standards. A time division multiple access (TDMA) system may implement a radio technology such as Global System for Mobile Communications (GSM). An orthogonal frequency division multiple access (OFDMA) system may implement a radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE <NUM> (Wi-Fi), IEEE <NUM> (WiMAX), IEEE <NUM>, Flash-OFDM, etc..

For synchronous operation, the stations may have similar frame timing, and transmissions from different stations may be approximately aligned in time. For asynchronous operation, the stations may have different frame timing, and transmissions from different stations may not be aligned in time.

For example, due to the nature of software, functions described above may be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these.

By way of example, and not limitation, non-transitory computer-readable media can comprise RAM, ROM, electrically erasable programmable read only memory (EEPROM), compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave are included in the definition of medium.

Claim 1:
A method for wireless communication, performed by a first wireless device, comprising:
identifying, by the first wireless device, a sequence of on symbols and off symbols for transmission to a wake-up radio, WUR, of a second wireless device (<NUM>);
determining a random or pseudorandom cyclic shift based at least in part on a random number generator, wherein the random number generator is initialized with a random or pseudorandom seed;
assigning a modulation symbol waveform from a set of possible modulation symbol waveforms to at least each on symbol in the sequence, wherein the modulation symbol waveforms are assigned to sequential on symbols in a random or pseudorandom order (<NUM>), and wherein assigning the modulation symbol waveform comprises selecting a random or pseudorandom cyclic shift for each symbol and applying the random or pseudorandom cycle shift to a stored modulation symbol waveform to generate the modulation symbol waveform for each symbol;
transmitting the sequence to the WUR of the second wireless device using multi-carrier on-off keying, MC-OOK, based at least in part on the assigned modulation symbol waveforms; and
transmitting the random or pseudorandom seed to the second wireless device.