Universal reservation signal for medium sharing

Wireless communications systems and methods related to signaling medium reservation information medium sharing among multiple radio technologies (RATs) are provided. A first wireless communication device communicates, with a second wireless communication device, a reservation signal to reserve a transmission opportunity (TXOP) in a spectrum. The spectrum is shared by multiple RATs. The reservation signal includes a plurality of first waveform sequences indicating medium reservation information detectable by the multiple RATs. The first wireless communication device and the second wireless communication device are associated with a first RAT of the multiple RATs. The first wireless communication device communicates, with the second wireless communication device using the first RAT, a communication signal in the spectrum during the TXOP.

TECHNICAL FIELD

This application relates to wireless communication systems and methods, and more particularly to signaling medium reservation information for medium sharing among multiple radio access technologies (RATs).

INTRODUCTION

To meet the growing demands for expanded mobile broadband connectivity, wireless communication technologies o are advancing from the LTE technology to a next generation new radio (NR) technology. NR may provision for dynamic medium sharing among network operators and different RATs in a licensed spectrum, a shared spectrum, and/or an unlicensed spectrum. For example, NR and Institute of Electrical and Electronics Engineers (IEEE) 802.11 (WiFi) technologies may be deployed over the same spectrum.

An approach to sharing a communication medium or spectrum among multiple RATs is to employ a listen-before-talk (LBT) procedure to ensure a particular channel is clear before transmitting a message. For example, a transmitting node may listen to the channel to determine whether there are active transmissions in the channel based on energy detection. While energy detection may have low computational complexity, energy detection-based LBT may provide limited system performance, for example, missed detection and/or false detection. A missed detection may lead to collision and a false detection may cause resource (e.g., spectrum) to be underutilized.

To improve the performance, channel listening may include the detection of a specific sequence. For example, another transmitting node may transmit a specific preamble sequence to indicate use of the channel prior to transmitting data in the channel. However, different RATs may use different numerologies (e.g., subcarrier spacing). For example, NR subcarrier spacing may not an integer multiple of WiFi subcarrier spacing. As such, the detection of a preamble transmitted by a different RAT may require resampling, and thus may be computationally complex. Accordingly, improved procedures for signaling medium reservation information across multiple RATs are desirable.

BRIEF SUMMARY OF SOME EXAMPLES

For example, in an aspect of the disclosure, a method of wireless communication includes communicating, by a first wireless communication device with a second wireless communication device, a reservation signal to reserve a transmission opportunity (TXOP) in a spectrum, wherein the spectrum is shared by multiple radio access technologies (RATs), wherein the reservation signal includes a plurality of first waveform sequences indicating medium reservation information detectable by the multiple RATs, and wherein the first wireless communication device and the second wireless communication device are associated with a first RAT of the multiple RATs; and communicating, by the first wireless communication device with the second wireless communication device using the first RAT, a communication signal in the spectrum during the TXOP.

In an additional aspect of the disclosure, an apparatus includes a transceiver configured to communicate, with a second wireless communication device, a reservation signal to reserve a transmission opportunity (TXOP) in a spectrum, wherein the spectrum is shared by multiple radio access technologies (RATs), wherein the reservation signal includes a plurality of first waveform sequences indicating medium reservation information detectable by the multiple RATs, and wherein the apparatus and the second wireless communication device are associated with a first RAT of the multiple RATs; and communicate, with the second wireless communication device using the first RAT, a communication signal in the spectrum during the TXOP.

In an additional aspect of the disclosure, a non-transitory computer-readable medium having program code recorded thereon, the program code includes code for causing a first wireless communication device to communicate, with a second wireless communication device, a reservation signal to reserve a transmission opportunity (TXOP) in a spectrum, wherein the spectrum is shared by multiple radio access technologies (RATs), wherein the reservation signal includes a plurality of first waveform sequences indicating medium reservation information detectable by the multiple RATs, and wherein the first wireless communication device and the second wireless communication device are associated with a first RAT of the multiple RATs; and code for causing the first wireless communication device to communicating, by the first wireless communication device with the second wireless communication device using the first RAT, a communication signal in the spectrum during the TXOP.

DETAILED DESCRIPTION

The present application describes mechanisms for signaling medium reservation information for medium sharing among multiple RATs. The disclosed embodiments employ a waveform-based universal reservation signal (URS) to indicate medium reservation information detectable by multiple RATs. The URS may include a plurality of waveform sequences. Each waveform sequence may correspond to an instance of a waveform sequence masked according to the medium reservation information. The medium reservation information may include a minimal amount of information sufficient for RAT-level medium sharing. For example, the medium reservation information may indicate a transmission opportunity (TXOP) duration and the RAT that is reserving the TXOP. The medium reservation information for medium sharing within a RAT may be carried in a separate reservation signal.

In an embodiment, the URS may include an additional short training field (STF) at the beginning of the URS prior to the waveform sequences carrying the medium reservation information. The STF may include a plurality of waveform sequence (e.g., repetitions of a waveform sequence) for synchronization and training at a receiver.

In an embodiment, different RATs may use different numerologies. For example, a transmitter of a particular RAT may transmit URSs using the numerology of the particular RAT and a receiver of a different RAT may adjust sample spacing during URS detection and processing. Alternatively, a transmitter may transmit multiple URSs, each using a different RAT and carrying the same medium reservation information.

Aspects of the present application can provide several benefits. For example, the use of waveform-based URSs enables a receiver to recover the transmitted medium reservation information based on waveform detection instead of data decoding. Data decoding may require resampling when a transmitting RAT is different from a receiving RAT. Thus, waveform detection may have a lower computational complexity than data decoding. The use of a repeating waveform sequence enables a receiver to detect the presence of a URS and/or recover the medium reservation information based on autocorrelations and/or cross-correlations, which may have a low computational complexity. The use of separate reservation signals for medium sharing within a RAT and medium sharing across RATs can reduce signaling overhead and complexity for the design of the RAT-level URSs. For example, reducing the amount of medium reservation information can reduce the number of URS waveforms. The use of URSs to communicate medium reservation information detectable by all RATs sharing a spectrum can improve overall system performance. While the disclosed embodiments may be described in the context of NR-based technology and WiFi-based technology, the disclosed embodiments are suitable for use in any wireless communication network with any type of RAT and any number of RATs.

FIG. 1illustrates a wireless communication network100according to embodiments of the present disclosure. The network100includes BSs105, UEs115, and a core network130. In some embodiments, the network100operates over a shared spectrum. The shared spectrum may be unlicensed or partially licensed to one or more network operators. Access to the spectrum may be limited and may be controlled by a separate coordination entity. In some embodiments, the network100may be a LTE or LTE-A network. In yet other embodiments, the network100may be a millimeter wave (mmW) network, a new radio (NR) network, a 5G network, or any other successor network to LTE. The network100may be operated by more than one network operator. Wireless resources may be partitioned and arbitrated among the different network operators for coordinated communication between the network operators over the network100.

The BSs105may wirelessly communicate with the UEs115via one or more BS antennas. Each BS105may provide communication coverage for a respective geographic coverage area110. In 3GPP, the term “cell” can refer to this particular geographic coverage area of a BS and/or a BS subsystem serving the coverage area, depending on the context in which the term is used. In this regard, a BS105may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or other types of cell. A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A pico cell may generally cover a relatively smaller geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A femto cell may also generally cover a relatively small geographic area (e.g., a home) and, in addition to unrestricted access, may also provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown inFIG. 1, the BSs105a,105band105care examples of macro BSs for the coverage areas110a,110band110c, respectively. The BSs105dis an example of a pico BS or a femto BS for the coverage area110d. As will be recognized, a BS105may support one or multiple (e.g., two, three, four, and the like) cells.

The BSs105may communicate with the core network130and with one another. The core network130may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some of the BSs105(e.g., which may be an example of an evolved NodeB (eNB), a next generation NodeB (gNB), or an access node controller (ANC)) may interface with the core network130through backhaul links132(e.g., S1, S2, etc.) and may perform radio configuration and scheduling for communication with the UEs115. In various examples, the BSs105may communicate, either directly or indirectly (e.g., through core network130), with each other over backhaul links134(e.g., X1, X2, etc.), which may be wired or wireless communication links.

Each BS105may also communicate with a number of UEs115through a number of other BSs105, where the BS105may be an example of a smart radio head. In alternative configurations, various functions of each BS105may be distributed across various BSs105(e.g., radio heads and access network controllers) or consolidated into a single BS105.

In some implementations, the network100utilizes orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-F-DM) on the UL. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, or the like. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. The system bandwidth may also be partitioned into subbands.

In an embodiment, a UE115attempting to access the network100may perform an initial cell search by detecting a primary synchronization signal (PSS) from a BS105. The PSS may enable synchronization of period timing and may indicate a physical layer identity value. The UE115may then receive a secondary synchronization signal (SSS). The SSS may enable radio frame synchronization, and may provide a cell identity value, which may be combined with the physical layer identity value to identify the cell. The SSS may also enable detection of a duplexing mode and a cyclic prefix length. Some systems, such as TDD systems, may transmit an SSS but not a PSS. Both the PSS and the SSS may be located in a central portion of a carrier, respectively.

After receiving the PSS and SSS, the UE115may receive a master information block (MIB), which may be transmitted in the physical broadcast channel (PBCH). The MIB may contain system bandwidth information, a system frame number (SFN), and a Physical Hybrid-ARQ Indicator Channel (PHICH) configuration. After decoding the MIB, the UE115may receive one or more system information blocks (SIBs). For example, SIB1may contain cell access parameters and scheduling information for other SIBs. Decoding SIB1may enable the UE115to receive SIB2. SIB2may contain radio resource configuration (RRC) configuration information related to random access channel (RACH) procedures, paging, physical uplink control channel (PUCCH), physical uplink shared channel (PUSCH), power control, SRS, and cell barring. After obtaining the MIB and/or the SIBs, the UE115can perform random access procedures to establish a connection with the BS105. After establishing the connection, the UE115and the BS105can enter a normal operation stage, where operational data may be exchanged.

In an embodiment, the network100may operate over a shared channel, which may include a licensed spectrum, a shared spectrum, and/or an unlicensed spectrum, and may support dynamic medium sharing. In addition, the network100may include multiple RATs. For example, some BSs105and/or UEs115may communicate over a spectrum using NR-based technology, while other BSs105and/or other UEs115may share the same spectrum for communications using WiFi-based technology. Mechanisms for medium sharing across multiple RATs are described in greater detail herein.

FIG. 2illustrates an example of a wireless communications network200that supports medium sharing across multiple RATs according to embodiments of the present disclosure. The network200may be similar to the network100.FIG. 2illustrates two BSs205and two UEs215for purposes of simplicity of discussion, though it will be recognized that embodiments of the present disclosure may scale to many more UEs215and/or BSs205. The BSs205and the UEs215may be similar to the BSs105and the UEs115, respectively.

In the network200, the BS205aserves the UE215ain a serving cell or a coverage area240using a first RAT, while the BS205bserves the UE215bin a serving cell or a coverage area245using a second RAT. The first RAT and the second RAT may be different RATs. For example, the first RAT may be an NR-based technology and the second RAT may be a WiFi-based technology. The BSs205and the UEs215of different RATs may communicate over the same spectrum in the using an LBT procedure. For example, the different RATs may be deployed over an unlicensed frequency band, for example, in the 6 gigahertz (GHz) frequency band with a bandwidth of about 500 megahertz (MHz).

To perform LBT, the BS205amay listen to the channel. When the channel is clear, the BS205amay transmit a reservation signal to reserve a TXOP in the spectrum. The reservation signal can silence nodes (e.g., the BS205band/or other UE215b) of the other RAT. Subsequently, the BS205amay communicate with the UE215ain the spectrum during the reserved TXOP.

To enable a node of a particular RAT to detect a reservation signal transmitted by a different RAT, the network200may employ a URS that is detectable by all RATs in the network200.

To minimize the detection complexity across different RATs, the network200may employ waveform-based URSs. For example, the network200may employ different waveforms to represent different medium reservation information. In addition, the network200may employ a repeating short-period waveform sequence and apply different mask patterns to the waveform sequences to represent different medium reservation information. Thus, the BS205band the UE215bmay determine medium reservation information from a URS transmitted by the BS205aor the UE215abased on waveform detection instead of data decoding. In addition, the waveform-based URSs can allow for a larger frequency and/or timing offset than content-based URSs. For example, an NR node may have a higher timing and/or frequency accuracies than a WiFi node.

To reduce the number of waveform sequences, the network200may include a minimum amount of medium reservation information in the URSs. For example, a URS may include information such as a reserved TXOP duration and the RAT reserving the TXOP. Preamble sequences, scheduling information, and/or other reservation information specific to the operations of the reserving RAT may be carried in a separate reservation signal for sharing among nodes of the reserving RAT. For example, the network200may include other BSs and/or UEs for the first RAT. The BS205amay transmit a separate reservation signal indicating scheduling information for the UE215ato silence other BSs and/or UEs of the first RAT after transmitting a URS. The use of a smaller number of waveform sequences reduces the length or the time span of a URS. The shorter URS length can lower collision rate.

Different RATs may use different numerologies (e.g., different subcarrier spacing and different sampling rates). In an embodiment, a transmitting node of a particular RAT may transmit a URS using the numerology of the particular RAT and a monitoring or detecting node of another RAT may account for the different numerologies during URS detection. For example, a detecting node may perform the detection using autocorrelation and/or cross-correlation and may account for different numerologies by adjusting sample block spacing during correlations.

In another embodiment, a transmitting node of a particular RAT may transmit multiple URSs, each with a different numerology, but carrying the same medium reservation information. The multiple URSs allow a detecting node of a particular RAT to perform URS detection based on the numerology of the particular RAT. For example, the BS205amay transmit a first URS using a numerology of the first RAT and a second URS using a numerology of the second RAT. The BS205band/or the UE215bmay detect a reservation from the BS205abased on the second URS using the numerology of the second RAT. Mechanisms for sharing a medium across different RATs are described in greater detail herein.

FIG. 3is a block diagram of an exemplary UE300according to embodiments of the present disclosure. The UE300may be a UE115or215as discussed above. As shown, the UE300may include a processor302, a memory304, a spectrum sharing module308, a transceiver310including a modem subsystem312and a radio frequency (RF) unit314, and one or more antennas316. These elements may be in direct or indirect communication with each other, for example via one or more buses.

The processor302may include a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a controller, a field programmable gate array (FPGA) device, another hardware device, a firmware device, or any combination thereof configured to perform the operations described herein. The processor302may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

The spectrum sharing module308may be used for various aspects of the present disclosure. For example, the spectrum sharing module308is configured to monitor for URSs transmitted by multiple RATs, determine medium reservation information from the detected URSs, generate and transmit URSs using numerologies of one or more RATs, and/or perform LBT, as described in greater detail herein.

As shown, the transceiver310may include the modem subsystem312and the RF unit314. The transceiver310can be configured to communicate bi-directionally with other devices, such as the BSs105and205. The modem subsystem312may be configured to modulate and/or encode the data from the memory304, and/or the spectrum sharing module308according to a modulation and coding scheme (MCS), e.g., a low-density parity check (LDPC) coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit314may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data from the modem subsystem312(on outbound transmissions) or of transmissions originating from another source such as a UE115or215or a BS105or205. The RF unit314may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver310, the modem subsystem312and the RF unit314may be separate devices that are coupled together at the UE215to enable the UE215to communicate with other devices.

The RF unit314may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information), to the antennas316for transmission to one or more other devices. This may include, for example, transmission of URSs according to embodiments of the present disclosure. The antennas316may further receive data messages transmitted from other devices. The antennas316may provide the received data messages for processing and/or demodulation at the transceiver310. The antennas316may include multiple antennas of similar or different designs in order to sustain multiple transmission links. The RF unit314may configure the antennas316.

FIG. 4is a block diagram of an exemplary BS400according to embodiments of the present disclosure. The BS400may be a BS105or205as discussed above. A shown, the BS400may include a processor402, a memory404, a spectrum sharing module408, a transceiver410including a modem subsystem412and a RF unit414, and one or more antennas416. These elements may be in direct or indirect communication with each other, for example via one or more buses.

The memory404may include a cache memory (e.g., a cache memory of the processor402), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, a solid state memory device, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or a combination of different types of memory. In some embodiments, the memory404may include a non-transitory computer-readable medium. The memory404may store instructions406. The instructions406may include instructions that, when executed by the processor402, cause the processor402to perform operations described herein. Instructions406may also be referred to as code, which may be interpreted broadly to include any type of computer-readable statement(s) as discussed above with respect toFIG. 4.

The spectrum sharing module408may be used for various aspects of the present disclosure. For example, the spectrum sharing module308is configured to monitor for URSs transmitted by multiple RATs, determine medium reservation information from the detected URSs, generate and transmit URSs using numerologies of one or more RATs, and/or perform LBT, as described in greater detail herein.

As shown, the transceiver410may include the modem subsystem412and the RF unit414. The transceiver410can be configured to communicate bi-directionally with other devices, such as the UEs115and215and/or another core network element. The modem subsystem412may be configured to modulate and/or encode data according to a MCS, e.g., a LDPC coding scheme, a turbo coding scheme, a convolutional coding scheme, a digital beamforming scheme, etc. The RF unit414may be configured to process (e.g., perform analog to digital conversion or digital to analog conversion, etc.) modulated/encoded data from the modem subsystem412(on outbound transmissions) or of transmissions originating from another source such as a UE115,215, or300. The RF unit414may be further configured to perform analog beamforming in conjunction with the digital beamforming. Although shown as integrated together in transceiver410, the modem subsystem412and the RF unit414may be separate devices that are coupled together at the BS105or205to enable the BS105to communicate with other devices.

The RF unit414may provide the modulated and/or processed data, e.g. data packets (or, more generally, data messages that may contain one or more data packets and other information), to the antennas416for transmission to one or more other devices. This may include, for example, transmission of information to complete attachment to a network and communication with a camped UE115,215, or300according to embodiments of the present disclosure. The antennas416may further receive data messages transmitted from other devices and provide the received data messages for processing and/or demodulation at the transceiver410. The antennas416may include multiple antennas of similar or different designs in order to sustain multiple transmission links.

FIG. 5illustrates a multi-RAT medium sharing scheme500according to embodiments of the present disclosure. The x-axis represents time in some constant units. The y-axis represents frequency in some constant units. The scheme500may be employed by nodes or devices of different RATs, such as the BSs105,205, and400and the UEs115,215, and300, to communicate over a shared spectrum501.

In the scheme500, communications in the spectrum501may be in units of TXOP502. A TXOP502may include a channel sensing period504followed by a transmission period506. The channel sensing period504may include an RRQ period507and an RRS period508. The RRQ period507may include a common period510, a filler period511, and a RAT-specific period512. Similarly, the RRS period508may include a common period514, a filler period515, and a RAT-specific period516. The RRQ period507, the RRS period508, and the transmission period506are spaced apart by gap periods509. The gap periods509allow time for processing at a receiver and/or switching between a transmit mode and a receive mode at a transmitter and/or at a receiver.

As an example, a transmitting node (e.g., the BSs205and the UEs215) using a particular RAT may transmit a URS520in the common period510of the RRQ period507to reserve the TXOP502. The URS520may indicate medium reservation information. For example, the medium reservation information may include a duration of the TXOP502and the RAT used by the transmitter to transmit the URS520. The URS520may be a waveform-based signal and may represent reservation information using different waveforms, as described in greater detail herein.

A node of another RAT contending for the channel may monitor the spectrum501for a URS520. For example, upon detection of a URS520, the node may refrain from communicating in the spectrum501. As such, the transmission of the URS520may silence nodes of other RATs for medium sharing across different RATs.

After transmitting the URS520, the transmitting node may transmit a RAT-specific RRQ signal540in the RAT-specific period512of the RRQ period507. The RAT-specific RRQ signal540may include a preamble, a request-to-send (RTS) signal, scheduling information for a target receiving node of the particular RAT, interference management related parameters, and/or spatial LBT information, which may require a receiver to perform content or data decoding. Nodes of the particular RAT may monitor the spectrum501and refrain from communicating in the spectrum501upon detection of the RAT-specific RRQ signal540. Thus, the transmission of the RAT-specific RRQ signal540may silence other nodes of the particular RAT for medium sharing within the particular RAT.

In an embodiment, when a monitoring node of a particular RAT detected a URS520transmitted by a node of a different RAT, the monitoring node may not proceed to receive and process the RAT-specific RRQ signal540. Conversely, when a monitoring node of a particular RAT detected a URS520transmitted by another node of the same RAT, the monitoring node may proceed to receive, process, and decode the content of the RAT-specific RRQ signal540.

In response to the URS520, the target receiving node may transmit a URS550in the common period514of the RRS period508. The URS550may be substantially similar to the URS520and may indicate substantially similar medium reservation information as the URS520. In addition, the target receiving node may respond to the RAT-specific RRQ signal540by transmitting a RAT-specific RRS signal560in the RAT-specific period516of the RRS period508. The RAT-specific RRS signal560may include a preamble and/or a clear-to-send (CTS) signal. Similar to the processing of the RAT-specific RRQ signal540, a monitoring node may not proceed to receive and process the RAT-specific RRS signal560when detecting a URS550transmitted by a different RAT.

Subsequently, the transmitting node may transmit a communication signal570to the target receiving node during the transmission period506. In some embodiments, the inclusion of the RRS period508in the transmission period506and the transmissions of the URS550and/or the RAT-specific RRS signal560may be optional.

In the scheme500, the TXOP502may have a variable duration dependent on the length of the communication signal570. In an embodiment, the timing of the TXOP502may be asynchronous to the timing of a serving cell of the transmitting node. Thus, the TXOP502may or may not align to a symbol boundary of the serving cell. The URSs520and550may have a fixed duration, but may or may not align to the symbol time of the serving cell. Thus, the URSs520and550may or may not end at a symbol boundary of the serving cell.

In order to allow the RAT-specific RRQ signal540and the RAT-specific RRS signal560to align to a symbol boundary of the serving cell, the transmitting node may transmit a filler signal530during the filler period511and the receiving node may transmit a filler signal532during the filler period515, respectively, to align to a next symbol boundary. In an embodiment, the filler signal530may be transmitted as an extension to the URS520. In another embodiment, the filler signal530may be transmitted as an extended cyclic prefix (CP) of the RAT-specific RRQ signal540. Similarly, the receiving node may transmit the filler signal532as an extension to the URS550or as an extended CP of the RAT-specific RRS signal560.

In an embodiment, the TXOP502may be reserved in some predetermined units of time or granularities, for example, in units of 10 microseconds (μs) or 1 millisecond (ms). Thus, the communication signal570may or may not end at the end of the TXOP502. When the communication signal570does not span the entire transmission period506, the transmitting node may transmit a filler signal534after the communication signal570to fill the filler period518. The filler signals530,532, and534may carry filler data, which may be dropped or ignored at a receiver.

FIGS. 6-8illustrate various mechanisms for generating waveform-based URSs (e.g., the URSs520and550), which may be used in conjunction with the scheme500in the networks100and200for multi-RAT medium sharing.

FIG. 6illustrates a URS generation scheme600for multi-RAT medium sharing according to embodiments of the present disclosure. The scheme600may be employed by the BSs105,205, and400and the UEs115,215, and300. The scheme600employs a plurality of waveform sequences610to represent medium reservation information. The plurality of waveform sequences610may correspond to instances or repetitions of a short-period waveform sequence, shown as S1, which may be a wideband signal or a narrowband signal spanning a duration602. In some embodiments, the duration602may be about 0.8 μs.

As an example, reservation information for a TXOP (e.g., the TXOP502) may be represented by Q number of information bits, denoted as I0, I1, . . . , IQ-1and the Q number of bits can be encoded into L number of coded bits, denoted as d0, d1, . . . , dL-1, where both Q and L are a positive integer. In some embodiments, Q is equal to L and Q number of information bits are identical to L number of coded bits. In some other embodiments, L>Q and Q number of bits is encoded into L number of coded bits. In some embodiments, Q is less than or equal to 8. The Q number of bits can support N number of reservation information hypotheses620, denoted as H(1) to H(N), where N=2Q. For example, each hypothesis620may indicate a duration of a TXOP reservation, the type of RAT (e.g., NR-based technology or WiFi-based technology) reserving the TXOP, and/or any suitable information for medium sharing across multiple RATs. The duration may be defined in some units of time, for example, in units of 1 ms. In an embodiment, a subset of the hypotheses620may be used to indicate TXOP reservations from an NR-based node with a TXOP duration in steps of 1 ms, while another subset of the hypotheses620may be used to indicate TXOP reservations from a WiFi-based node with a TXOP duration in steps of 1 ms. In an embodiment, a TXOP reservation may be a semi-static reservation. For example, a node may indicate a periodic TXOP reservation with a duration of 1 ms repeating at every 100 ms.

The scheme600includes a hypothesis selection component630, a mask generation component640, and a masking component650. The hypothesis selection component630is configured to select a hypothesis620H(k)from the hypotheses620H(1)to620H(N)to indicate particular medium reservation information, where 1≤K≤N. The mask generation component640is configured to generate a code or a mask642based on the Q information bits or the L coded bits of the selected hypothesis620H(k). The generation may be based on a spreading code, a Walsh code, a differential code, or any suitable code.

In an embodiment, the mask generation component640may employ differential encoding to generate the mask642. The mask generation component640encodes a difference between adjacent medium reservation information bits (e.g., d1and d2). For example, the mask generation component640may output a value of +1 when there is a bit change between a pair of adjacent medium reservation information bits and may output a value of −1 when there is no bit change between a pair of adjacent medium reservation information bits. Thus, the mask642may include L values, denoted as d0to with values of +1 and/or −1.

The masking component650is configured to apply the mask642to the plurality of waveform sequences610to produce a URS660(e.g., the URSs520and550) including a plurality of waveform sequences662. For example, the scheme600may apply the mask642of length L (e.g., L values) to L number of short-period waveform sequences610to represent Q medium reservation information bits. The masking component650may multiply the L short-period waveform sequences610by the mask642. Each short-period waveform sequence610is multiplied by one of the L mask bits, for example, represented by S1×di, where 0≤i≤L−1. Thus, each waveform sequence662corresponds to a waveform sequence610masked by a corresponding mask bit di.

The use of a repeating waveform sequence610for the URS660allows a receiver to use autocorrelation-based detection. For example, a receiver may apply autocorrelation to a received signal to determine the presence or the beginning of a URS660. When the mask642includes values of +1 and −1, the receiver may apply autocorrelation to detect a phase change between adjacent blocks of samples for detecting the coded bits (e.g., as d0, d1, . . . , dL-1) and recovering the original transmitted reservation information bits (e.g., as I0, I1, . . . , IQ-1). In some embodiment, the receiving RAT may have a different sampling rate than the transmitting RAT. In such embodiments, the receiver may adjust the sample between sample blocks for the autocorrelation, as described in greater detail herein.

FIG. 7illustrates a URS generation scheme700for multi-RAT medium sharing according to embodiments of the present disclosure. The scheme700may be employed by the BSs105,205, and400and the UEs115,215, and300. The scheme700is substantially similar to the scheme600. However, the scheme700employs a plurality of waveform sequences710in addition to the plurality of waveform sequences610to provide a receiver with training information. The plurality of waveform sequences710may correspond to instances or repetitions of a short-period waveform sequence, shown as S2, spanning a duration702.

In some embodiments, the waveform sequence710may be the same as the waveform sequence610, for example, S2=S1. In some embodiments, the waveform sequence710and the waveform sequence610may have opposite phases, for example, S2=−1×S1. In some embodiments, the waveform sequences710and the waveform sequence610may have different waveforms. In some embodiments, the durations702and602may be the same, for example, about 0.8 μs. In some embodiments, the durations702and602may be different.

As shown, the masking component650applies the mask642to the waveform sequences610to form a portion764of a URS760(e.g., the URSs520and550) carrying the medium reservation information. The waveform sequences710form a portion762at the beginning of the URS760. The waveform sequences710may provide training information for the reception of the URS760. For example, a receiver may perform time synchronization, frequency synchronization, automatic gain control, and/or packet detection based on the waveform sequences710. The portion762may be referred to as an STF. In an embodiment, the portion762may include about 10 waveform sequences710and the duration702may be about 0.8 μs. Thus, the portion762may have a duration of about 8 μs.

Similar to the scheme600, the use of a repeating waveform sequence710and a repeating waveform sequence610for the URS760allows a receiver to use autocorrelation-based detection. For example, a receiver may apply autocorrelation to a received signal to determine the presence or the beginning of a URS760. When the mask642includes values of +1 and/or −1, the receiver may apply autocorrelation to detect a phase change between adjacent blocks of samples for detecting the coded bits (e.g., as d0, d1, . . . , dL-1) and recovering the original transmitted reservation information bits (e.g., as I0, I1, . . . , IQ-1). In addition, the receiver may adjust the sample spacing between sample blocks for the autocorrelation, as described in greater detail herein.

FIG. 8illustrates a URS generation scheme800for multi-RAT medium sharing according to embodiments of the present disclosure. The scheme800may be employed by the BSs105,205, and400and the UEs115,215, and300. The scheme800is substantially similar to the schemes600. However, the scheme800employs different sets812of waveform sequences810, denoted as S(1) to S(M), to indicate different subsets622of hypotheses620in addition to different masks642. Each set812includes instances or repetitions of a different waveform sequence810. For example, the scheme800may employ the set812S(1)to carry medium reservation information for a subset622SS(1)of the hypotheses620and employ the set812S(M)to carry medium reservation information for a subset622SS(M)of the hypotheses620. Each waveform sequence810may have a fixed duration802.

The scheme800includes a waveform selection component830. The waveform selection component830is configured to select a set812S(P)from the sets812S(1)to812S(M)based on the selected hypothesis620H(k), where 1≤P≤M. Similar to the scheme600, the mask generation component640generates a mask642based on the selected hypothesis620H(k). The masking component650applies the mask642to the selected set812S(P)of waveform sequences810S(P)to produce a URS860(e.g., the URSs520and550). Similar to the URS660, the URS860includes a plurality of waveform sequences862, each corresponding to a waveform sequence610masked by a corresponding mask bit d1.

Similar to the scheme600, the use of a repeating waveform sequence810for the URS860allows a receiver to use autocorrelation-based and cross-correlation-based detection. For example, a receiver may apply autocorrelation to a received signal to determine the presence or the beginning of a URS860. After time-aligning to the URS860, the receiver may compute cross-correlations between the received signal and the different waveform sequences810S(1)to810S(M)to determine the waveform sequences in the URS860, and thus the corresponding hypothesis subset622. When the mask642includes values of +1 and −1, the receiver may apply autocorrelation to detect a phase change between adjacent blocks of received samples for detecting the coded bits (e.g., as d0, d1, . . . , dL-1) and recovering the original transmitted reservation information bits (e.g., as I0, I1. . . , IQ-1). In addition, the receiver may adjust the spacing between blocks of received samples for the autocorrelation and/or the cross-correlation, as described in greater detail herein.

In some embodiments, the scheme800may be used in conjunction with the scheme700. For example, the URS860may include an STF (e.g., the portion762) at the beginning of the URS860to provide training information for the reception of the URS860. While the schemes600,700, and800use different masks over a repeating waveform sequence or different masks over different repeating waveform sequence to represent different medium reservation information, similar mechanism can be applied to represent different medium reservation information using different repeating sequences. In addition, a mask can be applied over multiple short periods to represent 1 bit of information for each hypothesis or multiple bits of information for multiple hypotheses.

FIG. 9illustrates a URS transmission scheme900for multi-RAT medium sharing according to embodiments of the present disclosure. The scheme900may be employed by the BSs105,205, and400and the UEs115,215, and300to transmit URSs910(e.g., the URSs520,550,660,760, and860). As described above, a transmitter may transmit URSs based on the numerology (e.g., a sampling rate) of a serving cell of the transmitter. In the scheme900, a transmitter902may store a set of URSs910, denoted as URS1to URSN, for example, in a memory (e.g., the memory304and404) of the transmitter902.

The URSs910may be generated using the schemes600,700, and/or800based on a sampling rate of the serving cell. For example, an NR-based node may store the URSs910based on an NR sampling rate and a WiFi-based node may store the URSs910based on a WiFi sampling rate. Each URS910represents particular reservation information (e.g., a hypothesis620). For example, the URSs910may correspond to the URSs660,760, or860generated for the hypotheses620(e.g., H(1) to H(N)) using the schemes600,700, or800, respectively. The transmitter902may include a URS selection component920configured to select a URS910URS(k)from the URSs910URS(l)to910URS(N)based on a selected hypothesis620H(k). The transmitter902may transmit the selected URS910URS(k)in a spectrum (e.g., the spectrum501) to reserve a TXOP (e.g., the TXOP502).

FIG. 10illustrates a URS detection scheme1000for multi-RAT medium sharing according to embodiments of the present disclosure. InFIG. 10, the x-axis represents time in some constant units. The scheme1000may be employed by the BSs105,205, and400and the UEs115,215, and300to detect a URS (e.g., the URSs520,550,660,760,860, and910) and determine a hypothesis (e.g., the hypotheses620) from the URS. In the scheme1000, a receiver1002may receive a signal1010, denoted as Y, from a channel (e.g., the spectrum501). The receiver1002may include a correlation component1020configured to perform autocorrelation and/or cross-correlation. For example, the correlation component1020may perform autocorrelation between two blocks of samples of the signal1010.

As described above, different RATs may use different sampling rates, which may or not be integer multiple of each other. For example, NR may use a subcarrier spacing that is an integer multiple of 15 kilohertz (kHz), while WiFi may use 802.11ax subcarrier spacing that is an integer multiple of 78.125 kHz. Thus, the NR sampling frequency may not be an integer multiple of the WiFi sampling frequency. The correlation component1020may account for the different sampling rates when detecting a signal1010transmitted by a RAT (e.g., NR) different from a RAT (e.g., WiFi) of a serving cell of the receiver1002. The correlation component1020may apply time dithering to select blocks of samples from the signal1010for correlation instead of resampling the received signal1010to the sampling rate of the transmitting RAT.

As shown in the timing diagram1030, the correlation component1020may select a block1032of samples and a block1034of samples from the received signal1010. The block1032may include X number of samples, where X is a positive integer. The1034may include (X+1) number of samples. The value X may be determined based on the sampling rate of the RAT used by the serving cell and the sampling rate of the transmitting RAT. For example, a duration (e.g., the durations602,702, and802) of a waveform sequence (e.g., the waveform sequences610,710,712, and810) may include 100 samples based on the numerology of the transmitting RAT, but may include 91.5 samples based on the numerology of the receiving RAT. Thus, the receiver1002may configured X to be a value of 91.

The correlation component1020may compute a correlation between the X samples in the block1032and X samples in the block1034, for example, by dropping the last sample or the first sample in the block1034. In other words, the correlation component1020may adjust the spacing between blocks of samples for correlations, for example, by skipping or dropping one sample in alternate blocks. The rate of dropping or skipping a sample may be dependent on the sampling rates of the transmitting RAT and the receiving RAT. For example, the correlation component1020may drop one sample in every 2, 3, 4, or 5 blocks. The correlation component1020may apply similar sample dithering for computing cross-correlations, for example, when the received signal1010includes a URS860generated from the scheme800. In some embodiments, the correlation component1020may perform coherent combining on correlation results by considering phase differences between the blocks1032and1034due to the sample drop. In some embodiments, the receiver1002may perform additional interpolation to further improve URS detection performance.

FIG. 11illustrates a multi-RAT medium sharing scheme1100according to embodiments of the present disclosure. The x-axis represents time in some constant units. The y-axis represents frequency in some constant units. The scheme1100may be employed by nodes of different RATs, such as the BSs105,205, and400and the UEs115,215, and300, to communicate over a shared spectrum501. The scheme1100is substantially similar to the scheme500, but a transmitter may transmit multiple copies of a URS based on different RATs with different numerologies. For example, a transmitter may transmit a URS1120and a URS1122in the common period510of the RRS period508. The URSs1120and1122may be similar to the URSs520,550,660,760,860, and910. The URS1120and the URS1122may carry the same medium reservation information (e.g., the hypotheses620), but configured based on two different RATs.

As an example, the spectrum501is shared between an NR-based network and a WiFi-based network. The URS1120may be configured based on an NR numerology and the URS1122may be configured based on a WiFi numerology. For example, the URSs1120and1122may be generated using the scheme600. Thus, the URS1120may correspond to the URS660sampled at an NR sampling rate and the URS1120may correspond to the URS660sampled at a WiFi sampling rate.

Similarly, a target receiver may respond to the URSs1120and1122by transmitting a URS1150and a URS1152in the common period514of the RRS period508. The URSs1150and1152may carry the same medium reservation information, but configured based on numerologies of different RATs. While the scheme1100is illustrated with URSs configured for two different RATs, the scheme1100may be applied to a network supporting any suitable number of RATs. For example, when a network supports three different RATs, the scheme1100may be scaled to transmit three copies of the same medium reservation information carried in three URSs configured for the three different RATs in the common periods510and514.

The transmissions of multiple copies of reservation information using numerologies of different RATs allow a receiver to perform detection based on the numerology of a serving cell of the receiver. For example, when the URS1120is transmitted using NR and the URS1122is transmitted using WiFi, an NR-based receiver may detect and process the URS1120and a WiFi-based receiver may detect and process the URS1122.

FIG. 12is a flow diagram of a multi-RAT medium sharing method1200according to embodiments of the present disclosure. Steps of the method1200can be executed by a computing device (e.g., a processor, processing circuit, and/or other suitable component) of a wireless communication device, such as the BSs105,205, and400, the UEs115,215, and300, the transmitter902, and the receiver1002. The method1200may employ similar mechanisms as in the schemes500,600,700,800,900,1000, and1100described with respect toFIGS. 5, 6, 7, 8, 9, 10, and 11, respectively. As illustrated, the method1200includes a number of enumerated steps, but embodiments of the method1200may include additional steps before, after, and in between the enumerated steps. In some embodiments, one or more of the enumerated steps may be omitted or performed in a different order.

At step1210, the method1200includes communicating, by a first wireless communication device with a second wireless communication device, a reservation signal (e.g., the URSs520,550,660,760,860,910,1120,1122,1150, and1152) to reserve a TXOP (e.g., the TXOP502) in a spectrum (e.g., the spectrum501). The spectrum is shared by multiple RATs (e.g., NR and WiFi). The reservation signal includes a set of waveform sequence (e.g., the waveform sequences610,662,710,810, and862) indicating medium reservation information (e.g., the hypotheses620) detectable by the multiple RATs. The first wireless communication device and the second wireless communication device are associated with a first RAT of the multiple RATs.

At step1220, the method1200includes communicating, by the first wireless communication device and the second wireless communication device, a communication signal (e.g., the communication signal570) in the spectrum during the TXOP using the first RAT.

Further embodiments of the present disclosure include a method of wireless communication, comprising communicating, by a first wireless communication device with a second wireless communication device, a reservation signal to reserve a transmission opportunity (TXOP) in a spectrum, wherein the spectrum is shared by multiple radio access technologies (RATs), wherein the reservation signal includes a plurality of first waveform sequences indicating medium reservation information detectable by the multiple RATs, and wherein the first wireless communication device and the second wireless communication device are associated with a first RAT of the multiple RATs; and communicating, by the first wireless communication device with the second wireless communication device using the first RAT, a communication signal in the spectrum during the TXOP.

In some embodiments, wherein the medium reservation information indicates at least one of a reservation duration for the TXOP or a RAT type indicating that the TXOP is reserved by the first RAT. In some embodiments, wherein the plurality of first waveform sequences correspond to multiple instances of a second waveform sequence masked by a code representing the medium reservation information. In some embodiments, wherein the medium reservation information is represented by a phase difference between adjacent first waveform sequences of the plurality of first waveform sequences. In some embodiments, wherein the reservation signal includes a plurality of second waveform sequences providing information for reception of the reservation signal. In some embodiments, wherein the communicating the reservation signal includes transmitting, by the first wireless communication device to the second wireless communication device, the reservation signal, and wherein the method further comprises selecting, by the first wireless communication device, the plurality of first waveform sequences from a plurality of second waveform sequences based on the medium reservation information. In some embodiments, wherein the communicating the reservation signal includes receiving, by the first wireless communication device from the second wireless communication device, the reservation signal, and wherein the method further comprises identifying, by the first wireless communication device, the plurality of first waveform sequences based on a detection between the reservation signal and a plurality of second waveform sequences. In some embodiments, wherein the communicating the reservation signal includes transmitting, by the first wireless communication device, the reservation signal based on a numerology of the first RAT. In some embodiments, wherein the communicating the reservation signal includes transmitting, by the first wireless communication device based on a numerology of the first RAT, a first signal indicating the medium reservation information; and transmitting, by the first wireless communication device based on a numerology of a second RAT of the multiple RATs, a second signal indicating the medium reservation information. In some embodiments, the method further comprises receiving, by the first wireless communication device from a third wireless communication device, a reservation signal for another TXOP in the spectrum, the third wireless communication device associated with a second RAT of the multiple RATs; determining, by the first wireless communication device, medium reservation information associated with the second RAT from the reservation signal for the another TXOP; and refraining, by the first wireless communication device, from communicating in the spectrum during the another TXOP based on the medium reservation information associated with the second RAT. In some embodiments, wherein the reservation signal for the another TXOP is transmitted using a numerology of the first RAT. In some embodiments, wherein the reservation signal for the another TXOP is transmitted using a numerology of the second RAT. In some embodiments, wherein the receiving the reservation signal for the another TXOP includes performing, by the first wireless communication device, correlations based on samples of the reservation signal spaced apart by a first spacing associated with a numerology of the first RAT; and performing, by the first wireless communication device, correlations based on samples of the reservation signal spaced apart by a second spacing associated with a numerology of the second RAT. In some embodiments, the method further comprises communicating, by the first wireless communication device with the second wireless communication device, a filler signal in the spectrum during the TXOP based on a symbol boundary of the first RAT. In some embodiments, the method further comprises communicating, by the first wireless communication device with the second wireless communication device, a filler signal in the spectrum during the TXOP based on a duration of the TXOP. In some embodiments, the method further comprises communicating, by the first wireless communication device with the second wireless communication device, a first RAT-specific reservation signal including at least one of a preamble of the first RAT or scheduling information of the first RAT.

Further embodiments of the present disclosure include an apparatus comprising a transceiver configured to communicate, with a second wireless communication device, a reservation signal to reserve a transmission opportunity (TXOP) in a spectrum, wherein the spectrum is shared by multiple radio access technologies (RATs), wherein the reservation signal includes a plurality of first waveform sequences indicating medium reservation information detectable by the multiple RATs, and wherein the apparatus and the second wireless communication device are associated with a first RAT of the multiple RATs; and communicate, with the second wireless communication device using the first RAT, a communication signal in the spectrum during the TXOP.

In some embodiments, wherein the medium reservation information indicates at least one of a reservation duration for the TXOP or a RAT type indicating that the TXOP is reserved by the first RAT. In some embodiments, wherein the plurality of first waveform sequences correspond to multiple instances of a second waveform sequence masked by a code representing the medium reservation information. In some embodiments, wherein the medium reservation information is represented by a phase difference between adjacent first waveform sequences of the plurality of first waveform sequences. In some embodiments, wherein the reservation signal includes a plurality of second waveform sequences providing information for reception of the reservation signal. In some embodiments, wherein the transceiver is further configured to communicate the reservation signal by transmitting, to the second wireless communication device, the reservation signal, and wherein the apparatus further comprises a processor configured to select the plurality of first waveform sequences from a plurality of second waveform sequences based on the medium reservation information. In some embodiments, wherein the transceiver is further configured to communicate the reservation signal by receiving, from the second wireless communication device, the reservation signal, and wherein the apparatus further comprises a processor configured to identify the plurality of first waveform sequences based on a detection between the reservation signal and a plurality of second waveform sequences. In some embodiments, wherein the transceiver is further configured to communicate the reservation signal by transmitting the reservation signal based on a numerology of the first RAT. In some embodiments, wherein the transceiver is further configured to communicating the reservation signal by transmitting, based on a numerology of the first RAT, a first signal indicating the medium reservation information; and transmitting, based on a numerology of a second RAT of the multiple RATs, a second signal indicating the medium reservation information. In some embodiments, wherein the transceiver is further configured to receive, from a third wireless communication device, a reservation signal for another TXOP in the spectrum, the third wireless communication device associated with a second RAT of the multiple RATs, and wherein the apparatus further comprises a processor configured to determine medium reservation information associated with the second RAT from the reservation signal for the another TXOP; and refrain from communicating in the spectrum during the another TXOP based on the medium reservation information associated with the second RAT. In some embodiments, wherein the reservation signal for the another TXOP is transmitted using a numerology of the first RAT. In some embodiments, wherein the reservation signal for the another TXOP is transmitted using a numerology of the second RAT. In some embodiments, the apparatus further comprises a processor configured to perform correlations based on samples of the reservation signal for the another TXOP spaced apart by a first spacing associated with a numerology of the first RAT; and perform correlations based on samples of the reservation signal for the another TXOP spaced apart by a second spacing associated with a numerology of the second RAT. In some embodiments, wherein the transceiver is further to communicate, with the second wireless communication device, a filler signal in the spectrum during the TXOP based on a symbol boundary of the first RAT. In some embodiments, wherein the transceiver is further to communicate, with the second wireless communication device, a filler signal in the spectrum during the TXOP based on a duration of the TXOP. In some embodiments, wherein the transceiver is further to communicate, with the second wireless communication device, a first RAT-specific reservation signal including at least one of a preamble of the first RAT or scheduling information of the first RAT.

Further embodiments of the present disclosure include a computer-readable medium having program code recorded thereon, the program code comprising code for causing a first wireless communication device to communicate, with a second wireless communication device, a reservation signal to reserve a transmission opportunity (TXOP) in a spectrum, wherein the spectrum is shared by multiple radio access technologies (RATs), wherein the reservation signal includes a plurality of first waveform sequences indicating medium reservation information detectable by the multiple RATs, and wherein the first wireless communication device and the second wireless communication device are associated with a first RAT of the multiple RATs; and code for causing the first wireless communication device to communicating, by the first wireless communication device with the second wireless communication device using the first RAT, a communication signal in the spectrum during the TXOP.

In some embodiments, wherein the medium reservation information indicates at least one of a reservation duration for the TXOP or a RAT type indicating that the TXOP is reserved by the first RAT. In some embodiments, wherein the plurality of first waveform sequences correspond to multiple instances of a second waveform sequence masked by a code representing the medium reservation information. In some embodiments, wherein the medium reservation information is represented by a phase difference between adjacent first waveform sequences of the plurality of first waveform sequences. In some embodiments, wherein the reservation signal includes a plurality of second waveform sequences providing information for reception of the reservation signal. In some embodiments, wherein the code for causing the first wireless communication device to communicate the reservation signal is further configured to transmit, to the second wireless communication device, the reservation signal, and wherein the computer-readable medium further comprises code for causing the first wireless communication device to select the plurality of first waveform sequences from a plurality of second waveform sequences based on the medium reservation information. In some embodiments, wherein the code for causing the first wireless communication device to communicate the reservation signal is further configured to receive, from the second wireless communication device, the reservation signal, and wherein the computer-readable medium further comprises code for causing the first wireless communication device to identify the plurality of first waveform sequences based on a detection between the reservation signal and a plurality of second waveform sequences. In some embodiments, wherein the code for causing the first wireless communication device to communicate the reservation signal is further configured to transmit the reservation signal based on a numerology of the first RAT. In some embodiments, wherein the code for causing the first wireless communication device to communicate the reservation signal is further configured to transmit, based on a numerology of the first RAT, a first signal indicating the medium reservation information; and transmit, based on a numerology of a second RAT of the multiple RATs, a second signal indicating the medium reservation information. In some embodiments, the computer-readable medium further comprises code for causing the first wireless communication device to receive, from a third wireless communication device, a reservation signal for another TXOP in the spectrum, the third wireless communication device associated with a second RAT of the multiple RATs; code for causing the first wireless communication device to determine medium reservation information associated with the second RAT from the reservation signal for the another TXOP; and code for causing the first wireless communication device to refrain from communicating in the spectrum during the another TXOP based on the medium reservation information associated with the second RAT. In some embodiments, wherein the reservation signal for the another TXOP is transmitted using a numerology of the first RAT. In some embodiments, wherein the reservation signal for the another TXOP is transmitted using a numerology of the second RAT. In some embodiments, wherein the code for causing the first wireless communication device to receive the reservation signal for the another TXOP is further configured to perform correlations based on samples of the reservation signal spaced apart by a first spacing associated with a numerology of the first RAT; and perform correlations based on samples of the reservation signal spaced apart by a second spacing associated with a numerology of the second RAT. In some embodiments, the computer-readable medium further comprises code for causing the first wireless communication device to communicate, with the second wireless communication device, a filler signal in the spectrum during the TXOP based on a symbol boundary of the first RAT. In some embodiments, the computer-readable medium further comprises code for causing the first wireless communication device to communicate, with the second wireless communication device, a filler signal in the spectrum during the TXOP based on a duration of the TXOP. In some embodiments, the computer-readable medium further comprises code for causing the first wireless communication device to communicate, with the second wireless communication device, a first RAT-specific reservation signal including at least one of a preamble of the first RAT or scheduling information of the first RAT.

Further embodiments of the present disclosure include an apparatus comprising means for communicating, with a second wireless communication device, a reservation signal to reserve a transmission opportunity (TXOP) in a spectrum, wherein the spectrum is shared by multiple radio access technologies (RATs), wherein the reservation signal includes a plurality of first waveform sequences indicating medium reservation information detectable by the multiple RATs, and wherein the apparatus and the second wireless communication device are associated with a first RAT of the multiple RATs; and means for communicating, with the second wireless communication device using the first RAT, a communication signal in the spectrum during the TXOP.

In some embodiments, wherein the medium reservation information indicates at least one of a reservation duration for the TXOP or a RAT type indicating that the TXOP is reserved by the first RAT. In some embodiments, wherein the plurality of first waveform sequences correspond to multiple instances of a second waveform sequence masked by a code representing the medium reservation information. In some embodiments, wherein the medium reservation information is represented by a phase difference between adjacent first waveform sequences of the plurality of first waveform sequences. In some embodiments, wherein the reservation signal includes a plurality of second waveform sequences providing information for reception of the reservation signal. In some embodiments, wherein the means for communicating the reservation signal is further configured to transmit, to the second wireless communication device, the reservation signal, and wherein the apparatus further comprises means for selecting the plurality of first waveform sequences from a plurality of second waveform sequences based on the medium reservation information. In some embodiments, wherein the means for communicating the reservation signal is further configured to receive, from the second wireless communication device, the reservation signal, and wherein the apparatus further comprises means for identifying the plurality of first waveform sequences based on a detection between the reservation signal and a plurality of second waveform sequences. In some embodiments, wherein the means for communicating the reservation signal is further configured to transmit the reservation signal based on a numerology of the first RAT. In some embodiments, wherein the means for communicating the reservation signal is further configured to transmit, based on a numerology of the first RAT, a first signal indicating the medium reservation information; and transmit, based on a numerology of a second RAT of the multiple RATs, a second signal indicating the medium reservation information. In some embodiments, the apparatus further comprises means for receiving, from a third wireless communication device, a reservation signal for another TXOP in the spectrum, the third wireless communication device associated with a second RAT of the multiple RATs; means for determining medium reservation information associated with the second RAT from the reservation signal for the another TXOP; and means for refraining from communicating in the spectrum during the another TXOP based on the medium reservation information associated with the second RAT. In some embodiments, wherein the reservation signal for the another TXOP is transmitted using a numerology of the first RAT. In some embodiments, wherein the reservation signal for the another TXOP is transmitted using a numerology of the second RAT. In some embodiments, wherein the means for receiving the reservation signal for the another TXOP is further configured to perform correlations based on samples of the reservation signal spaced apart by a first spacing associated with a numerology of the first RAT; and perform correlations based on samples of the reservation signal spaced apart by a second spacing associated with a numerology of the second RAT. In some embodiments, the apparatus further comprises means for communicating, with the second wireless communication device, a filler signal in the spectrum during the TXOP based on a symbol boundary of the first RAT. In some embodiments, the apparatus further comprises means for communicating, with the second wireless communication device, a filler signal in the spectrum during the TXOP based on a duration of the TXOP. In some embodiments, the apparatus further comprises means for communicating, with the second wireless communication device, a first RAT-specific reservation signal including at least one of a preamble of the first RAT or scheduling information of the first RAT.