Patent Description:
Wireless communication systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. Examples of such multiple-access systems include code-division multiple access (CDMA) systems, time-division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, and orthogonal frequency-division multiple access (OFDMA) systems.

By way of example, a wireless multiple-access communication system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, otherwise known as user equipments (UEs). A base station may communicate with UEs on downlink channels (e.g., for transmissions from a base station to a UE) and uplink channels (e.g., for transmissions from a UE to a base station).

A wireless multiple-access communication system may use frequency division multiplexing (FDM) to multiplex different users within a frequency band. For example OFDMA uses orthogonal sub-carriers or tones to provide defined resource elements. A numerology for an OFDMA system defines the sub-carrier spacing, symbol length, and cyclic prefix ratio. Different OFDMA systems may use different numerologies. When different OFDMA systems are present, the frequency bands used by the systems are generally separated by a guard band with no transmissions.

The <NUM> mobile standard is currently being formulated and calls for higher data transfer speeds, greater numbers of connections, and better coverage, among other improvements. The <NUM> standard, according to the Next Generation Mobile Networks Alliance, is expected to provide data rates of several tens of megabits per second to each of tens of thousands of users, with <NUM> gigabit per second to tens of workers on an office floor. Several hundreds of thousands of simultaneous connections should be supported in order to support large sensor deployments. Consequently, the spectral efficiency of <NUM> mobile communications should be significantly enhanced compared to the current <NUM> standard. Furthermore, signaling efficiencies should be enhanced and latency should be substantially reduced compared to current standards.

Accordingly, there is a need for development of better transmission/processing techniques for wireless data transmission to meet different requirements of different applications/users at the same time. IEEE publication "<NPL>. ) describes the targets for NB-IoT and present a preliminary system design. In addition, coverage, capacity, latency, and battery life analysis are also presented. <NPL>) discusses the flexible numerology for the new RAT based on the assumption that the design is based on OFDM based waveform. <CIT> provide a communication method and an apparatus thereof. The method includes: generating a first signal; and sending the first signal to a receive end over a first channel, where the first channel is one of multiple channels in a first band for narrowband communication, and at least a part of the first band is located in a guard band of a radio access network RAN. In the embodiments of the present invention, a spectrum resource of a guard band of a RAN is used to establish a spectrum resource applicable to narrowband communication, thus improving spectrum utilization.

The described features generally relate to using a guard band between a first frequency band utilized by a first radio access technology (RAT) using a first sub-carrier spacing and a second frequency band utilized by a second RAT using a second sub-carrier spacing that is a multiple of the first sub-carrier spacing. Generally, OFDMA uses orthogonal sub-carriers to prevent inter carrier interference. The guard band separates different frequency bands where the applicable RATs use different sub-carrier spacing that would result in non-orthogonal sub-carriers. The guard band typically includes no transmissions and may be viewed as unutilized spectrum.

According to aspects of the present disclosure, a guard band signal may be transmitted and received on the guard band to utilize the previously unutilized spectrum. In the case where a second sub-carrier spacing is a multiple of the first sub-carrier spacing, the guard band signal can be structured so that it minimizes inter carrier interference with both the first frequency band and the second frequency band. For example, by repeating an OFDMA symbol and managing a cyclic prefix (CP) for each symbol, the guard band signal may comply with the numerology of both the first RAT and the second RAT. The waveforms utilized may include any OFDM-based waveform with CP, such as CP-OFDM and discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM).

As used in this application, the terms "component," "module," "system" and the like are intended to include a computer-related entity, such as but not limited to hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a computing device and the computing device can be a component. One or more components can reside within a process and/or thread of execution and a component can be localized on one computer and/or distributed between two or more computers. In addition, these components can execute from various computer readable media having various data structures stored thereon. The components can communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets, such as data from one component interacting with another component in a local system, distributed system, and/or across a network such as the Internet with other systems by way of the signal.

Techniques described herein may be used for various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms "system" and "network" may often be used interchangeably. IS-<NUM> Releases <NUM> and A are commonly referred to as CDMA2000 1X, 1X, etc. IS-<NUM> (TIA-<NUM>) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. An 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. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). The techniques described herein may be used for the systems and radio technologies mentioned above as well as other systems and radio technologies, including cellular (e.g., LTE) communications over a shared radio frequency spectrum band. The description below, however, describes an LTE/LTE-A system for purposes of example, and LTE terminology is used in much of the description below, although the techniques are applicable beyond LTE/LTE-A applications (e.g., to <NUM> networks or other next generation communication systems).

<FIG> illustrates an example of a wireless communication system <NUM> in accordance with various aspects of the present disclosure. The wireless communication system <NUM> may include one or more base stations <NUM>, one or more UEs <NUM>, and a core network <NUM>. The core network <NUM> may provide user authentication, access authorization, tracking, internet protocol (IP) connectivity, and other access, routing, or mobility functions. The base stations <NUM> may interface with the core network <NUM> through backhaul links <NUM> (e.g., S1, etc.). The base stations <NUM> may perform radio configuration and scheduling for communication with the UEs <NUM>, or may operate under the control of a base station controller (not shown). In various examples, the base stations <NUM> may communicate, either directly or indirectly (e.g., through core network <NUM>), with one another over backhaul links <NUM> (e.g., X1, etc.), which may be wired or wireless communication links.

The base stations <NUM> may wirelessly communicate with the UEs <NUM> via one or more base station antennas. In some examples, base stations <NUM> may be referred to as a network entity, a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, eNodeB (eNB), Home NodeB, a Home eNodeB, or some other suitable terminology. The geographic coverage area <NUM> for a base station <NUM> may be divided into sectors making up only a portion of the coverage area (not shown). The wireless communication system <NUM> may include base stations <NUM> of different types (e.g., macro or small cell base stations). There may be overlapping geographic coverage areas <NUM> for different technologies.

In some examples, the wireless communication system <NUM> may be or include a Long Term Evolution (LTE) or LTE-Advanced (LTE-A) network. The wireless communication system <NUM> may also be a next generation network, such as a <NUM> wireless communication network. For example, the communication system <NUM> may be a narrow-band Internet of Things (NB-IoT) network, a <NUM> new radio (NR) network, or use a combination of RATs. In LTE/LTE-A networks, the term evolved node B (eNB) may be generally used to describe the base stations <NUM>, while the term UE may be generally used to describe the UEs <NUM>. The wireless communication system <NUM> may be a heterogeneous LTE/LTE-A network in which different types of eNBs provide coverage for various geographical regions. For example, each eNB or base station <NUM> may provide communication coverage for a macro cell, a small cell, or other types of cell. The term "cell" is a 3GPP term that can be used to describe a base station, a carrier or component carrier associated with a base station, or a coverage area (e.g., sector, etc.) of a carrier or base station, depending on context.

A macro cell may generally cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs <NUM> with service subscriptions with the network provider.

A small cell may include a lower-powered base station, as compared with a macro cell, that may operate in the same or different (e.g., licensed, unlicensed, etc.) frequency bands as macro cells.

The communication networks that may accommodate some of the various disclosed examples may be packet-based networks that operate according to a layered protocol stack and data in the user plane may be based on the IP. A radio link control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A MAC layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use HARQ to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the radio resource control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE <NUM> and the base stations <NUM>. The RRC protocol layer may also be used for core network <NUM> support of radio bearers for the user plane data. At the physical (PHY) layer, the transport channels may be mapped to physical channels.

The UEs <NUM> may be dispersed throughout the wireless communication system <NUM>, and each UE <NUM> may be stationary or mobile. A UE <NUM> may also include or be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology. A UE <NUM> may be a cellular phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a tablet computer, a laptop computer, a cordless phone, a wireless local loop (WLL) station, an entertainment device, a vehicular component, or the like. A UE may be able to communicate with various types of base stations and network equipment including macro eNBs, small cell eNBs, relay base stations, and the like.

The wireless communication links <NUM> shown in wireless communication system <NUM> may carry UL transmissions from a UE <NUM> to a base station <NUM>, or downlink (DL) transmissions, from a base station <NUM> to a UE <NUM>. The downlink transmissions may also be called forward link transmissions while the uplink transmissions may also be called reverse link transmissions. Each wireless communication link <NUM> may include one or more carriers, where each carrier may be a signal made up of multiple sub-carriers (e.g., waveform signals of different frequencies) modulated according to the various radio technologies described above. Each modulated signal may be sent on a different sub-carrier and may carry control information (e.g., reference signals, control channels, etc.), overhead information, user data, etc. The communication links <NUM> may transmit bidirectional communications using frequency division duplex (FDD) (e.g., using paired spectrum resources) or time division duplex (TDD) operation (e.g., using unpaired spectrum resources). Frame structures may be defined for FDD (e.g., frame structure type <NUM>) and TDD (e.g., frame structure type <NUM>).

In aspects of the wireless communication system <NUM>, base stations <NUM> or UEs <NUM> may include multiple antennas for employing antenna diversity schemes to improve communication quality and reliability between base stations <NUM> and UEs <NUM>. Additionally or alternatively, base stations <NUM> or UEs <NUM> may employ multiple input multiple output (MIMO) techniques that may take advantage of multi-path environments to transmit multiple spatial layers carrying the same or different coded data.

Wireless communication system <NUM> may support operation on multiple cells or carriers, a feature which may be referred to as carrier aggregation (CA) or multi-carrier operation. A carrier may also be referred to as a component carrier (CC), a layer, a channel, etc. The terms "carrier," "component carrier," "cell," and "channel" may be used interchangeably herein. A UE <NUM> may be configured with multiple downlink CCs and one or more uplink CCs for carrier aggregation.

In aspects of the wireless communication system <NUM>, the wireless communication system <NUM> may utilize guard band signals at the PHY layer. That is, the guard band signals described herein may be utilized to transmit higher layer data.

In aspects of the wireless communication system <NUM>, a base station <NUM> may include a guard band signal component <NUM> (see e.g., <FIG>) configured to transmit guard band signals to one or more UEs <NUM> and/or receive guard band signals from one or more UEs. Similarly, in an aspect, a UE <NUM> may include a guard band signal component <NUM> configured to transmit guard band signals to a base station <NUM> and/or receive a guard band signal from a base station <NUM>. The guard band signals may be utilized when the base station <NUM> and UE <NUM> are communicating using one of the neighboring frequency bands, or may be utilized independently of the neighboring frequency bands.

Referring to <FIG>, a block diagram <NUM> is shown that includes a portion of a wireless communications system having multiple UEs <NUM> in communication with a base station <NUM> via communication links <NUM>, where the base station <NUM> is also connected to a network <NUM>. The UEs <NUM> may be examples of the UEs described in the present disclosure that are configured to receive and process guard band signals. Moreover the base station <NUM> may be an example of the base stations described in the present disclosure that are configured to generate and transmit guard band signals. Either the base station <NUM> or the UE <NUM> may be a device <NUM> including a guard band signal component <NUM>.

In an aspect, the device <NUM> in <FIG> may include one or more processors <NUM> and/or memory <NUM> that may operate in combination with guard band signal component <NUM> to perform the functions, methodologies (e.g., method <NUM> of <FIG> and method <NUM> of <FIG>), or methods presented in the present disclosure. In accordance with the present disclosure, the guard band signal component <NUM> may include a guard band signal generator <NUM> having an optional subcarrier spacing component <NUM>, an optional Tx timing component <NUM>, and a guard band signal decoder <NUM>, which may optionally include an optional Rx timing component <NUM>.

The one or more processors <NUM> may include a modem <NUM> that uses one or more modem processors. The various functions related to the guard band signal component <NUM> may be included in modem <NUM> and/or processor <NUM> and, in an aspect, can be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors <NUM> may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a transceiver processor associated with transceiver <NUM>, or a system-on-chip (SoC). In particular, the one or more processors <NUM> may execute functions and components included in the guard band signal component <NUM>.

In some examples, the guard band signal component <NUM> and each of the subcomponents may comprise hardware, firmware, and/or software and may be configured to execute code or perform instructions stored in a memory (e.g., a computer-readable storage medium, such as memory <NUM> discussed below). Moreover, in an aspect, the base station <NUM> in <FIG> may include a radio frequency (RF) front end <NUM> and transceiver <NUM> for receiving and transmitting radio transmissions to, for example, UEs <NUM>. The transceiver <NUM> may coordinate with the modem <NUM> to transmit messages generated by the guard band signal component <NUM> (e.g., guard band signals <NUM> in <FIG>) to the UEs. RF front end <NUM> may be connected to one or more antennas <NUM> and can include one or more switches <NUM>, one or more amplifiers (e.g., power amplifiers (PAs) <NUM> and/or low-noise amplifiers <NUM>), and one or more filters <NUM> for transmitting and receiving RF signals on uplink channels and downlink channels. In an aspect, the components of the RF front end <NUM> can connect with transceiver <NUM>. The transceiver <NUM> may connect to one or more of modem <NUM> and processors <NUM>.

The transceiver <NUM> may be configured to transmit (e.g., via transmitter (Tx) radio <NUM>) and receive (e.g., via receiver (Rx) radio <NUM>) wireless signals through antennas <NUM> via the RF front end <NUM>. In an aspect, the transceiver <NUM> may be tuned to operate at specified frequencies such that the base station <NUM> can communicate with, for example, UEs <NUM>. In an aspect, for example, the modem <NUM> can configure the transceiver <NUM> to operate at a specified frequency and power level based on the configuration of the base station <NUM> and communication protocol used by the modem <NUM>.

The base station <NUM> in <FIG> may further include a memory <NUM>, such as for storing data used herein and/or local versions of applications or guard band signal component <NUM> and/or one or more of its subcomponents being executed by processor <NUM>. Memory <NUM> can include any type of computer-readable medium usable by a computer or processor <NUM>, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory <NUM> may be a computer-readable storage medium that stores one or more computer-executable codes defining guard band signal component <NUM> and/or one or more of its subcomponents. Additionally or alternatively, the base station <NUM> may include a bus <NUM> for coupling one or more of the RF front end <NUM>, the transceiver <NUM>, the memory <NUM>, or the processor <NUM>, and to exchange signaling information between each of the components and/or subcomponents of the base station <NUM>.

The guard band signal generator <NUM> of the guard band signal component <NUM> may be configured to generate guard band signals that minimize inter carrier interference to neighboring frequency bands. Generally, a guard band signal may be transmitted using a sub-carrier spacing that is a multiple of the sub-carrier spacing used on one neighboring frequency band and the same as the sub-carrier spacing used on the other neighboring frequency band. Further, the guard band signal may repeat symbols in the time domain. Additionally, cyclic prefixes may be added to the guard band signal such that the guard band signal matches the structure of both the first RAT and the second RAT. Accordingly, the guard band signal may be interpreted according to a numerology of the first RAT or according to numerology of the second RAT. <FIG>, and <FIG> illustrate example implementations of processing performed by the guard band signal generator <NUM> and are described in further detail below.

The guard band signal generator <NUM> may optionally include a subcarrier spacing component <NUM> for determining scalable subcarrier spacing. For example, the subcarrier spacing component <NUM> may determine whether scalable subcarrier spacing is utilized on neighboring frequency bands. For example in NB-IoT, sub-carrier spacing of <NUM> may be used, while in <NUM> NR sub-carrier spacing of <NUM> may be used. If the guard band separates a NB-IoT frequency band from a <NUM> NR frequency band, the subcarrier spacing component <NUM> may determine that scalable sub-carrier spacing is used because the <NUM> sub-carrier spacing is a multiple of the <NUM> sub-carrier spacing. As another example, other networks may support more than one subcarrier spacing (e.g., <NUM>, <NUM>, or <NUM>). The subcarrier spacing component <NUM> may determine which sub-carrier spacing is in use one each neighboring frequency band and determine whether the sub-carrier spacings are scalable (e.g., multiples).

The guard band signal generator <NUM> may optionally include a Tx timing component <NUM> for detecting a timing offset between the first radio access technology and the second radio access technology. The Tx timing component <NUM> may also synchronize the guard band signal with one of the first radio access technology or the second radio access technology.

The guard band signal decoder <NUM> may be configured to receive a guard band signal transmitted by another device <NUM>. The guard band signal decoder <NUM> may process the guard band signal to extract encoded information and pass the information to higher layers. The guard band signal decoder <NUM> may utilize properties of the guard band signal to correctly decode the encoded information. <FIG> and <FIG> illustrate example implementations of processing performed by the guard band signal decoder <NUM> and are described in further detail below.

The guard band signal decoder <NUM> may optionally include an Rx timing component <NUM> for detecting a timing offset between the first radio access technology and the second radio access technology. The guard band signal may be synchronized with one of the first radio access technology or the second radio access technology. For example, the guard band signal decoder <NUM> may compare configuration information and/or synchronization channels to determine the timing offset between the first radio access technology and the second radio access technology. The Rx timing component <NUM> may also select a FFT window based on the timing offset that avoids interference from the other of the first radio access technology or the second radio access technology. For example, the Rx timing component <NUM> may select an FFT window based on the timing offset that includes a portion of a symbol and a portion of a cyclic prefix of the other of the first radio access technology or the second radio access technology, as described in further detail below with respect to <FIG>.

In an aspect, the processor(s) <NUM> may correspond to one or more of the processors described in connection with the base station or UE in <FIG>. Similarly, the memory <NUM> may correspond to the memory described in connection with the base station or the UE in <FIG>.

Turning now to <FIG> and <FIG>, aspects are depicted with reference to one or more components and one or more methods that may perform the actions or operations described herein, where aspects in dashed line may be optional. Although the operations described below in <FIG> and <FIG> are presented in a particular order and/or as being performed by an example component, it should be understood that the ordering of the actions and the components performing the actions may be varied, depending on the implementation. Moreover, it should be understood that the following actions, functions, and/or described components may be performed by a specially-programmed processor, a processor executing specially-programmed software or computer-readable media, or by any other combination of a hardware component and/or a software component capable of performing the described actions or functions.

Referring to <FIG>, a flow chart illustrating an example method <NUM> for transmitting a guard band signal from a device such as the base stations <NUM> described in this disclosure.

At block <NUM>, the method <NUM> may include generating, a guard band signal for transmission on a guard band. The guard band may be a frequency band between a first frequency band utilized by a first RAT having a first sub-carrier spacing and a second frequency band utilized by a second RAT having a second sub-carrier spacing that is a multiple of the first sub-carrier spacing. In an aspect, the guard band signal generator <NUM> may generate the guard band signal.

In an aspect, block <NUM> may optionally include, at block <NUM>, generating modulation symbols based on data to transmit. Generating modulation symbols may be based on any modulation technique known in the art.

In an aspect, block <NUM> may optionally include, at block <NUM>, performing phase rotation on periodic modulation symbols according to the multiple based on a cyclic prefix length of a second numerology corresponding to the second sub-carrier spacing. For example, if the multiple is <NUM>, every other modulation symbol (e.g., even symbols) may be phase rotated based on a cyclic prefix length of the second numerology.

In an aspect, block <NUM> may optionally include, at block <NUM>, performing an inverse fast Fourier transform (IFFT) on the modulation symbols. In an aspect, block <NUM> may optionally include, at block <NUM>, serializing time domain symbols from the IFFT.

In an aspect, block <NUM> may optionally include, at block <NUM>, performing a cyclic shift on periodic time domain symbols according to the multiple based on a cyclic prefix length of the second numerology. For example, if the multiple is <NUM>, a cyclic shift may be performed on every other symbol to move a first portion of the symbol having a cyclic prefix length to the end of the symbol. This cyclic shift may effectively add a cyclic postfix to the symbol.

In an aspect, block <NUM> may optionally include, at block <NUM>, allocating modulation symbols to periodic inputs of the IFFT according to the multiple. For example, if the multiple is <NUM>, modulation symbols may be allocated to every other input tone of the IFFT.

In an aspect, block <NUM> may optionally include, at block <NUM> adding a cyclic prefix. The cyclic prefix may be based on a cyclic prefix length according to either the first numerology or the second numerology depending on which numerology will be used to decode the guard band signal. Further, in an aspect, the cyclic prefix may be used to adjust for time differences between the first RAT and the second RAT. For example, the cyclic prefix length may be reduced to align the guard band symbols with the first RAT or the second RAT.

In an aspect, block <NUM> may optionally include, at block <NUM>, detecting a timing offset between the first radio access technology and the second radio access technology. In an aspect, for example, Tx timing component <NUM> may detect a timing offset between the first radio access technology and the second radio access technology. For example, the Tx timing component <NUM> may compare transmit configurations and/or received synchronization signals for the first radio access technology and the second radio access technology.

In an aspect, block <NUM> may optionally include, at block <NUM>, Synchronize the synchronizing the guard band signal with one of the first radio access technology or the second radio access technology. In an aspect, for example, the Tx timing component <NUM> may synchronize the guard band signal with one of the first radio access technology or the second radio access technology. For example, the Tx timing component <NUM> may configure Tx Radio <NUM> to begin transmitting a guard band signal at the same time as a signal for the first radio access technology or the second radio access technology is being transmitted.

In block <NUM>, the method <NUM> may include transmitting the guard band signal on the guard band. In an aspect, for example, the guard band signal generator <NUM> may provide the guard band signal to the transceiver <NUM> for transmission on the guard band via the RF front end <NUM> and the antenna <NUM>.

At block <NUM>, the method <NUM> may include receiving, a guard band signal on a guard band. The guard band may be a frequency band between a first frequency band utilized by a first RAT having a first sub-carrier spacing and a second frequency band utilized by a second RAT having a second sub-carrier spacing that is a multiple of the first sub-carrier spacing. In an aspect, the guard band signal component <NUM> may receive the guard band signal from the transceiver <NUM>.

At block <NUM>, the method <NUM> may include decoding the guard band signal based on the multiple and the first sub-carrier spacing or the second sub-carrier spacing. In an aspect, the guard band signal decoder <NUM> may decode the guard band signal based on the multiple and the first sub-carrier spacing or the second sub-carrier spacing.

At block <NUM>, the method <NUM> may optionally include detecting a timing offset between the first radio access technology and the second radio access technology, wherein the guard band signal is synchronized with one of the first radio access technology or the second radio access technology. In an aspect, for example, the Rx timing component <NUM> may detect a timing offset between the first radio access technology and the second radio access technology. The Rx timing component <NUM> may further detect that the guard band signal is synchronized with one of the first radio access technology or the second radio access technology. For example, the Rx timing component <NUM> may compare channel configuration information and/or synchronization signals to detect the timing offset.

At block <NUM>, the method <NUM> may optionally select a FFT window based on the timing offset that avoids interference from the other of the first radio access technology or the second radio access technology. In an aspect, for example, the Rx timing component <NUM> may select a FFT window based on the timing offset that avoids interference from the other of the first radio access technology or the second radio access technology. The Rx timing component <NUM> may select the FFT window based on the timing offset that includes a portion of a symbol and a portion of a cyclic prefix of the other of the first radio access technology or the second radio access technology.

In an aspect, block <NUM> may optionally include, at block <NUM>, removing a cyclic prefix. Removing the cyclic prefix may be based on a cyclic prefix length according to either the first numerology or the second numerology. Further, removing the cyclic prefix may include utilizing the cyclic prefix to adjust for timing differences between the first radio access technology and the second radio access technology. For example, the cyclic prefix may be used to replace an end portion of the symbol that was cut off to adjust for the timing differences.

In an aspect, block <NUM> may optionally include, at block <NUM>, allocating serial time domain symbols to FFT inputs. In an aspect, block <NUM> may optionally include, at block <NUM>, performing a fast Fourier transform (FFT) on the time domain symbols.

In an aspect, block <NUM> may optionally include, at block <NUM>, performing a phase de-rotation on periodic tones according to the multiple based on a cyclic prefix length of the second numerology. For example, if the multiple is <NUM>, every other tone may be de-rotated based on the cyclic prefix length of the second numerology.

In an aspect, block <NUM> may optionally include, at block <NUM>, combining a set of the multiple number of consecutive tones. For example, if the multiple is <NUM>, a de-rotated tone may be combined with a consecutive tone that was not de-rotated. The consecutive tones may be repetitions. Accordingly, the repetitions may provide redundancy that improves the likelihood of correctly decoding the signal. In an aspect, maximum ratio combining may be used to combine the tones.

In an aspect, block <NUM> may optionally include, at block <NUM>, extracting only periodic tones from the FFT according to the multiple. For example, if the multiple is <NUM>, only every other tone may be extracted from the FFT. In an aspect, only the tones that do not require de-rotation may be extracted.

In an aspect, block <NUM> may optionally include, at block <NUM>, demodulating the tones. The demodulating may be performed according to the modulation technique used to modulate the data. Demodulating the tones may produce the original data that was transmitted.

<FIG> is a diagram <NUM> illustrating an example of neighboring frequency bands <NUM>, <NUM>. In an aspect, a first frequency band <NUM> may be utilized by a first RAT and a second frequency band <NUM> may be utilized by a second RAT. In the illustrated example, the first frequency band <NUM> may be utilized by a NB-IoT service while the second frequency band <NUM> may be utilized by a <NUM> NR service. It should be appreciated that other services or RATs may utilize neighboring frequency bands. The first frequency band <NUM> may be separated from the second frequency band <NUM> by a guard band <NUM>. Typically, the guard band <NUM> does not include transmissions. Accordingly, the guard band <NUM> typically prevents inter carrier interference by reducing energy leaking into a neighboring frequency band. According to aspects of the present disclosure, the guard band <NUM> may be utilized for transmission.

<FIG> illustrates an example of scalable subcarrier spacing <NUM>. Diagram <NUM> illustrates a first subcarrier spacing of <NUM>. In the time domain, the diagram <NUM> shows a waveform having a single copy or repetition of a symbol when a base or basic subcarrier spacing is used (e.g., <NUM>). For example, the diagram <NUM> may correspond to a first sub-carrier spacing for a first frequency band <NUM>. The base or basis subcarrier spacing may refer to the smallest subcarrier spacing utilized in neighboring frequency bands. Diagram <NUM> illustrates a waveform having two concatenated copies or repetitions of a symbol shown when a multiple (X2) of base or basic subcarrier spacing is used (e.g., <NUM>). For example, the diagram <NUM> may correspond to a second subcarrier spacing for the second frequency band <NUM>. Diagram <NUM> illustrates a waveform having eight concatenated copies or repetitions of a symbol shown when a multiple (X2 x X4) of base or basic subcarrier spacing is used.

<FIG> illustrates an example of a narrow band internet of things (NB-IoT) signal <NUM>. The NB-IoT signal <NUM> may be utilized in the first frequency band <NUM>. In this example, the NB-IoT signal <NUM> may be considered to use the base sub-carrier spacing (e.g., <NUM>). The NB-IoT signal <NUM> includes a single NB-IoT symbol <NUM> during a time period (e.g., a symbol period). A NB-IoT cyclic prefix <NUM> is added to the start of the NB-IoT symbol <NUM>. The NB-IoT cyclic prefix <NUM> is copied from an end portion of the NB-IoT symbol <NUM>.

<FIG> illustrates an example of a <NUM> NR signal <NUM>. The NR signal <NUM> may be utilized in the second frequency band <NUM>. In this example, the NR signal <NUM> may be considered to use a multiple (e.g., <NUM>) of the base sub-carrier spacing (e.g., <NUM>). Accordingly, the sub-carrier spacing for the NR signal <NUM> is two times the sub-carrier spacing for the NB-IoT signal <NUM>. The NR signal <NUM> includes a two NR symbols <NUM>, <NUM> during the time period (e.g., the symbol period for the NB-IoT symbol). A NR cyclic prefix <NUM>, <NUM> is added to the start of each of the NR symbols <NUM>, <NUM>. Each NR cyclic prefix <NUM>, <NUM> is copied from an end portion of the respective NR symbol <NUM>, <NUM>.

<FIG> illustrates an example of a guard band signal <NUM>. The guard band signal <NUM> has the same sub-carrier spacing and symbol length as the NR signal <NUM>. Accordingly the sub-carrier spacing for the guard band signal <NUM> is also a multiple (e.g., <NUM>) of the sub-carrier spacing of the NB-IoT signal <NUM>. As illustrated, the guard band signal <NUM> includes two symbols within a symbol period of the NB-IoT signal <NUM>. Each symbol may be a cyclic prefixed orthogonal frequency division multiplex (CP-OFDM) symbol including a IFFT symbol portion and a cyclic prefix portion <NUM>. Instead of transmitting different symbols in consecutive symbol periods as in the NR signal <NUM>, the guard band signal <NUM> may include a repeated IFFT symbol referred to as the guard band (GB) symbol <NUM>. That is, in the second symbol period, the same symbol is transmitted. In an aspect, the guard band symbol <NUM> is cyclically shifted in the subsequent symbol by the length of the cyclic prefix. The cyclic prefix portion for each guard band symbol <NUM>, is based on the end portion of the cyclically shifted symbol. In the first symbol period, a first cyclic prefix portion <NUM> is copied from the end of the guard band symbol <NUM>. In the second symbol period, a cyclic postfix portion <NUM> is copied from the beginning of the guard band symbol <NUM> and concatenated to the end of the guard band symbol <NUM>. Accordingly, the guard band signal <NUM> matches the structure for both NB-IoT and NR. Alternatively, the cyclic prefix portion <NUM> is obtained by cyclically shifting the guard band symbol <NUM>, then taking a cyclic prefix from the shifted symbol.

On one hand, if interpreted as an NB-IoT signal including a single signal during the symbol period, a cyclic prefix including the first cyclic prefix portion <NUM> and the cyclic postfix portion <NUM> is located at the beginning of symbol and corresponds to the end of the symbol period. Accordingly, at least in terms of numerology, the structure of the guard band signal <NUM> matches the structure of signal <NUM>. Therefore, the guard band signal <NUM> may be orthogonal to the signal <NUM> and may minimize inter carrier interference. On the other hand, if interpreted as an NR signal having a symbol period of half the NB-IoT symbol period, the first cyclic prefix portion <NUM> matches the end of the first guard band symbol <NUM> and the cyclic postfix portion <NUM>, which is copied from the start of the second GB symbol <NUM>, matches the start of the second GB symbol <NUM>. Accordingly, the start of the second GB symbol <NUM> can be interpreted as a cyclic prefix based on the cyclic postfix portion <NUM>. Therefore, in terms of numerology, the guard band signal <NUM> also matches the structure of NR signal <NUM>. Thus, the guard band signal <NUM> may be orthogonal to the NR signal <NUM> and may minimize inter carrier interference.

<FIG> illustrates an example of a guard band signal <NUM>, where the sub-carrier spacing of a second numerology is a multiple of <NUM> of the sub-carrier spacing of the first numerology. Accordingly, the symbol period under the second numerology is <NUM>/<NUM> the symbol period of the first numerology. When interpreted under the second numerology, the guard band signal <NUM> has three symbols, each including an IFFT symbol portion referred to as a guard band symbol <NUM>, <NUM>, <NUM> and a respective cyclic prefix portion <NUM>, <NUM>, <NUM>. Accordingly, each symbol is a CP-OFDM symbol according to the second numerology. In the first symbol, the cyclic prefix portion <NUM> is based on the end portion of the first symbol. In the second symbol, the guard band symbol <NUM> is cyclically shifted. The cyclic shift <NUM> is equal to the cyclic prefix length. The cyclic prefix portion <NUM> is based on the end portion of the cyclically shifted second guard band symbol <NUM>. In the third symbol, the guard band symbol <NUM> is cyclically shifted <NUM> by twice the cyclic prefix length (or the second guard band symbol <NUM> is cyclically shifted by the cyclic prefix length). Accordingly, the second guard band symbol <NUM> is a cyclic shifted copy of the IFFT symbol portion of the preceding symbol <NUM> and the cyclic shift is equal to the cyclic prefix length in the second numerology. Similarly the third guard band signal <NUM> is a cyclic shifted copy of the IFFT symbol portion of the preceding symbol <NUM> and the cyclic shift is equal to the cyclic prefix length in the second numerology.

<FIG> illustrates an example of transmission processing <NUM> for a guard band signal. For example, the guard band signal generator <NUM> may perform the processing <NUM> illustrated in <FIG> based on a symbol length and cyclic prefix length corresponding to a sub-carrier spacing that is a multiple of the sub-carrier spacing. For example, the processing in <FIG> may be performed based on NR symbol length and cyclic prefix length. Data <NUM> may be provided to a modulator <NUM>. The modulator <NUM> may modulate the data according to a modulation scheme (e. g, BPSK, QPSK, <NUM> QAM, <NUM> QAM) to generate modulation symbols. The processing <NUM> may include a number of branches equal to the multiple of the sub0carrier spacing. In the case of a multiple of <NUM>, the odd symbols are sent to a first branch <NUM> and the even symbols are sent to a second branch <NUM>. In the case of a greater multiple (N), Every Nth symbol may be sent to the same branch. The first branch <NUM> performs the inverse fast Fourier transform (IFFT) at block <NUM> to convert the symbols to the time domain. The symbols are then serialized from the parallel branches of the IFFT at block <NUM>. A cyclic prefix is added to each symbol to generate the odd transmission symbols at block <NUM>. In the second branch <NUM>, at block <NUM>, the phase of the modulation symbols is first rotated according to the cyclic prefix length. The second branch then performs, at block <NUM>, the IFFT and then serializes the time domain symbols at block <NUM>. A cyclic prefix (based on the rotated symbol) is then added to each of the symbols to form the even transmission symbols at block <NUM>.

<FIG> illustrates another example of transmission processing <NUM> for a guard band signal. The processing <NUM> in <FIG> may be performed by the guard band signal generator <NUM> based on the symbol length and cyclic prefix length corresponding to a sub-carrier spacing that is a multiple of the sub-carrier spacing. The processing in <FIG> may be equivalent to the processing illustrated in <FIG>. The processing in the first branch <NUM> for the odd symbols may be the same as illustrated in <FIG>. In the second branch <NUM>, the IFFT may be performed first at block <NUM>, followed by the serialization of the time domain symbols at block <NUM>. Instead of a phase rotation, a cyclic shift may be performed at block <NUM> in the time domain to move the cyclic postfix portion <NUM> to the end of the symbol. The cyclic prefix may then be performed at block <NUM> to copy the end portion to the beginning of the symbol.

<FIG> illustrates an example of receive processing <NUM> for a guard band signal. In an aspect, the receive processing may be performed by the guard band signal decoder <NUM> based on a symbol length and cyclic prefix length corresponding to a sub-carrier spacing that is a multiple of the sub-carrier spacing. For a multiple of <NUM>, the received symbols may be sent towards <NUM> branches <NUM>, <NUM>. If the multiple is greater than <NUM>, a number of branches equal to the multiple may be used. In the first branch <NUM>, the cyclic prefix may be removed from each of the odd symbols at block <NUM>. The serial symbols may then be arranged in parallel at block <NUM> and then fed to the FFT for conversion to the frequency domain at block <NUM>. Similarly, in the second branch <NUM>, the cyclic prefix is removed from each of the even symbols at block <NUM>. The serial symbols may be arranged in parallel in block <NUM> and fed an FFT at block <NUM>. In the second branch <NUM>, the frequency domain symbols are then phase de-rotated based on the cyclic prefix length at block <NUM>. The odd symbols from the first branch and the even symbols from the second branch are then combined using maximum ratio combining at block <NUM>. The combined symbols are then demodulated at block <NUM> to obtain the decoded data <NUM>.

<FIG> illustrates an example of alternative transmission processing <NUM> for a guard band signal. In an aspect, the guard band signal generator <NUM> may perform the processing <NUM> illustrated in <FIG> based on a symbol period corresponding to the base sub-carrier spacing of a first RAT (e.g., for NB-IoT) and the multiple N of the sub-carrier spacing for the second RAT. A modulator <NUM> may modulate data to obtain modulation symbols. In the case of a multiple of <NUM>, the modulation symbols may then be allocated only to even tones or sub-carriers at block <NUM>. In the case of a multiple of N, the modulation symbols may be allocated to every Nth tone. Accordingly, at block <NUM>, the IFFT may produce the repeated guard band symbols <NUM>. The parallel symbols from the IFFT may be serialized at block <NUM>. A cyclic prefix having a length corresponding to the base sub-carrier spacing may then be added to each symbol at block <NUM>.

<FIG> illustrates an example of alternative receive processing <NUM> for a guard band signal. In an aspect, the guard band signal decoder <NUM> may perform the processing <NUM> illustrated in <FIG> based on a symbol period corresponding to the base sub-carrier spacing (for a first RAT, e.g., for NB-IoT) and a multiple of the sub-carrier spacing for the second RAT. The guard band signal decoder <NUM> may receive time domain symbols <NUM> corresponding to the output of processing <NUM>. At block <NUM>, a cyclic prefix having a length based on the base sub-carrier spacing may be removed from the received time domain symbols <NUM>. At block <NUM>, the serial time domain symbols may be parallelized and fed to parallel inputs of the FFT <NUM>. The FFT <NUM> may convert the time domain symbols into frequency domain tones. In the case of a multiple of <NUM>, the guard band signal decoder <NUM> may extract only the even tones from the FFT at block <NUM>. In the case of a multiple of N, the guard band signal decoder <NUM> may extract every Nth tone from the FFT. At block <NUM>, the even tones may be demodulated to provide the decoded data <NUM> that was originally input into the processing <NUM>.

<FIG> illustrates an example of timing offsets between a first RAT transmission, a second RAT transmission, and a guard band transmission. The first RAT transmission may be, for example, the NB-IoT signal <NUM>. A receiving device may align a receive window <NUM> with the NB-IoT symbol <NUM>. The second RAT transmission may be, for example, the NR signal <NUM>. A receiving device may align a receive window <NUM> with each NR symbol <NUM>. The first RAT transmission and the second RAT transmission may be offset in time by an offset <NUM>. For example, as illustrated, the symbols for the second RAT transmission may start the offset <NUM> after the symbols for the first RAT transmission. The order may also be reversed. When the first RAT transmission and the second RAT transmission are offset (i.e., not time aligned), the guard band transmission may be aligned with either of the RAT transmissions, or configured with its own offset between the start of the first RAT transmission and the second RAT transmission.

In a first example, a guard band transmission <NUM> may be aligned with the NB-IoT signal <NUM>. The receiving device may align a receive window <NUM> with the NB-IoT signal <NUM>. For example, due to the alignment, of the guard band transmission <NUM> with the NB-IoT signal <NUM>, the GB receive window <NUM> may start one CP length (e.g., the length of CP <NUM>) after the start of the NB-IoT signal <NUM>. If the receive window <NUM> is used to receive the NR signal <NUM>, the receive window will include a portion of the NR CP1 <NUM> and a beginning of the NR symbol <NUM> such that the receiving device should be able to decode the NR symbol <NUM> using the NR CP1 <NUM>.

In a second example, a guard band transmission <NUM> may be aligned with the NR signal <NUM>. The receiving device may align a receive window <NUM> with the NR signal <NUM>. For example, due to the alignment, of the guard band transmission <NUM> with the NR signal <NUM>, the GB receive window <NUM> may start one CP length (e.g., the length of CP <NUM>) after the start of the NR signal <NUM>. The receive window <NUM> may be aligned with the receive window <NUM>. If a receive window <NUM> for the NB-IoT signal <NUM> is based on the GB receive window <NUM>, the receive window may include a portion of the NB-IoT CP1 <NUM> and the NB-IoT symbol <NUM>. Accordingly, the NB-IoT signal <NUM> may be decodable.

In a third example, the guard band transmission <NUM> may be aligned between the first RAT transmission and the second RAT transmission. The receiving device may align a receive window <NUM> with the GB symbols <NUM> based on the timing of the guard band transmission <NUM>. The receive window <NUM> may not be aligned with either the receive window <NUM> or the receive window <NUM>. The receive window <NUM> may, however, overlap a portion of the NR symbol <NUM> and the NR CP <NUM> so that the NR signal <NUM> is decodable. Similarly, a receive window <NUM> for NB-IoT based on the timing of the guard band transmission <NUM> may also overlap the NB-IoT symbol <NUM> and the NB-IoT CP <NUM> such that the NB-IoT signal <NUM> is decodable. In this case, although use of the CP may be used for both NB-IoT signal <NUM> and NR signal <NUM>, the chances of the receive window extending beyond the desired symbols resulting in intersymbol interference may be reduced for the worst case scenario (e.g., the RAT with which the guard band transmission is not aligned).

<FIG> is a block diagram of a MIMO communication system <NUM> including a base station <NUM> and a UE <NUM>. The MIMO communication system <NUM> may illustrate aspects of the wireless communication system <NUM> and diagram <NUM> described with reference to <FIG> and <FIG>. The base station <NUM> may be an example of aspects of the base station <NUM> described with reference to <FIG>, <FIG>, and <FIG>. The base station <NUM> may be equipped with antennas <NUM> and <NUM>, and the UE <NUM> may be equipped with antennas <NUM> and <NUM>. In the MIMO communication system <NUM>, the base station <NUM> may be able to send data over multiple communication links at the same time. Each communication link may be called a "layer" and the "rank" of the communication link may indicate the number of layers used for communication. For example, in a 2x2 MIMO communication system where base station <NUM> transmits two "layers," the rank of the communication link between the base station <NUM> and the UE <NUM> is two.

The UE <NUM> may be an example of aspects of the UEs <NUM> described with reference to <FIG>, <FIG>, and <FIG>. At the UE <NUM>, the UE antennas <NUM> and <NUM> may receive the DL signals from the base station <NUM> and may provide the received signals to the modulator/demodulators <NUM> and <NUM>, respectively. Each modulator/demodulator <NUM> through <NUM> may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each modulator/demodulator <NUM> through <NUM> may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector <NUM> may obtain received symbols from the modulator/demodulators <NUM> and <NUM>, perform MIMO detection on the received symbols, if applicable, and provide detected symbols. A receive (Rx) processor <NUM> may process (e.g., demodulate, deinterleave, and decode) the detected symbols, providing decoded data for the UE <NUM> to a data output, and provide decoded control information to a processor <NUM>, or memory <NUM>.

The processor <NUM> may in some cases execute stored instructions to instantiate a guard band signal component <NUM> (see e.g., <FIG> and <FIG>).

Claim 1:
A method of transmission in wireless communications, comprising:
generating (<NUM>), a guard band signal for transmission on a guard band (<NUM>), wherein the guard band (<NUM>) is between a first frequency band (<NUM>) utilized by a first radio access technology having a first sub-carrier spacing and a second frequency band (<NUM>) utilized by a second radio access technology having a second sub-carrier spacing that is a multiple of the first sub-carrier spacing, wherein the guard band signal includes a symbol that is repeated a number of times equal to the multiple, and wherein the guard band signal is interpretable according to a first numerology of the first radio access technology and according to a second numerology of the second radio access technology; and
transmitting (<NUM>) the guard band signal on the guard band (<NUM>).