Patent Description:
Network operators are rolling out narrowband Internet-of-Things (NB-IoT) networks at a fast pace. Within the next few years a massive number of devices may be connected to the networks, addressing a wide spectrum of IoT use cases. In the next few years, <NUM> billion wide-area IoT devices may be connected to cellular IoT networks.

Because IoT devices may have a <NUM>-year battery lifetime, many of the IoT devices will remain in service years after deployment. During the lifetime of these deployed IoT devices, many networks will undergo long term evolution (LTE) to fifth generation (<NUM>) new radio (NR) migration.

A smooth migration without service interruption to deployed IoT devices is extremely important to mobile network operators (MNO). Furthermore, a migration solution that ensures superior radio resource utilization efficiency and superior coexistence performance between NB-IoT and NR is highly desirable. In this regard, the ability of NR resource reservation in time domain and frequency domain can facilitate the coexistence of NR and NB-IoT.

There currently exist certain challenges with embedding an NB-IoT carrier inside a <NUM> NR carrier in a time division duplex (TDD) band. In general, if the NB-IoT carrier can be placed arbitrarily then this would satisfy its channel raster requirement. But this type of flexibility requires a large guard band to be reserved within an NR carrier to prevent interference between the two systems.

The document <NPL>), proposes techniques to facilitate the coexistence of NB-IoT with NR.

As described above, certain challenges currently exist with embedding a first radio access technology (RAT) within a second RAT (e.g., embedding an NB-IoT carrier inside a <NUM> NR carrier in a time division duplex (TDD) band). Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges.

For example, particular embodiments described herein include solutions for improved coexistence of a narrowband Internet-of-Things (NB-IoT) carrier embedded inside a fifth generation (<NUM>) new radio (NR) carrier in a time division duplex (TDD) band.

Some embodiments determine the placement of an NB-IoT carrier within an NR carrier that ensures orthogonality between NR and NB-IoT. For example, some embodiments identify the locations of NB-IoT carrier for which the NR and NB-IoT subcarriers can be aligned. Moreover, along with subcarrier alignment, resource block (RB) alignment enhances the resource efficiency thus reducing overhead in the NB-IoT and NR coexistence. Analysis of the subcarrier and RB alignments in NR and NB-IoT systems derives the possible locations of NB-IoT carrier for which both subcarrier and RB alignments are met in TDD case.

Particular embodiments include identification of the RB indexes where RB alignment is possible for NR and NB-IoT coexistence. Particular embodiments include a list of RB indexes where the NB-IoT carrier can be deployed for various NR system bandwidths with specific number of RBs.

Particular embodiments address the subcarrier grids alignment as well as RB alignment in NR and NB-IoT coexistence in TDD bands (e.g., n41, n77, n78, n79) when channel raster is not based on <NUM>. In particular, some embodiments focus on TDD bands with subcarrier spacing (SCS)-based channel raster. For <NUM> SCS, the channel raster is <NUM>. For various NR system bandwidths and NR channel raster locations in such bands, particular embodiments determine the indexes of NR RBs which can be used for deploying NB-IoT.

Particular embodiments effectively deploy NB-IoT in coexistence with NR operating in TDD with SCS-based channel raster (i.e., when channel raster is not based on <NUM>). More specifically, particular embodiments address the problems of subcarrier grids alignment and RB alignment, which are key issues in the coexistence of NR and NB-IoT. When deploying NB-IoT inside an NR band, particular embodiments determine the best locations of NB-IoT carrier where both subcarrier and RB alignments are achieved.

Certain embodiments may provide one or more of the following technical advantages. For example, some embodiments effectively deploy NB-IoT in coexistence with NR using TDD with SCS-based channel raster (i.e., when channel raster is not based on <NUM>). More specifically, particular embodiments address the problems of subcarrier grids alignment and RB alignment, which are key issues in the coexistence of NR and NB-IoT. When deploying NB-IoT inside an NR band, particular embodiments determine optimal locations of NB-IoT carrier to achieve both subcarrier and RB alignments.

As described above, certain challenges currently exist with embedding a first radio access technology (RAT) within a second RAT, such as embedding narrowband Internet-of-Things (NB-IoT) carrier inside a fifth generation (<NUM>) new radio (NR) carrier in a time division duplex (TDD) band. Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges.

Particular embodiments are described more fully with reference to the accompanying drawings.

In existing Third Generation Partnership Project (3GPP) agreements regarding the coexistence of TDD NB-IoT with NR, the only TDD band used by NB-IoT and NR is band # n41. Examples used herein analyze the in-band deployment of an anchor NB-IoT carrier inside an NR carrier in TDD band n41. Note that the analysis may be applied to any other TDD bands (e.g., n77, n78, n79) with SCS-based channel raster.

Particular examples may include a downlink (DL) coexistence scenario in which both NR and NB-IoT have <NUM> subcarrier spacing (SCS). Because NR and NB-IoT adopt orthogonal frequency-division multiple access (OFDMA) in downlink, it is possible to achieve the subcarrier orthogonality between these systems. The possible NR system bandwidths for <NUM> SCS in band <NUM> are currently: <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. The bandwidth for NB-IoT carrier is <NUM>, which corresponds to one NR resource block.

For an efficient coexistence between NR and NB-IoT, particular embodiments deploy the NB-IoT carrier (i.e., one RB) inside the NR carrier such that: <NUM>) inter-subcarrier interference between two systems is avoided (e.g., aligning the subcarrier grids between NR and NB-IoT); and <NUM>) the minimum number of NR resources are reserved for NB-IoT (e.g., aligning the NB-IoT RB with an NR RB so that only one NR RB needs to be reserved for NB-IoT). Note that, if the NB-IoT carrier is not efficiently deployed, two NR RBs may need to be reserved, which degrades NR resource utilization.

With respect to the embodiments described herein, the NR raster defines a subset of NR radio frequency (RF) reference frequencies that can be used to identify the RF channel position in the uplink and downlink. The NR RF reference frequency for an RF channel maps to a resource element (e.g., a subcarrier) on the carrier. Hereinafter, the NR channel raster is referred to as a point on the raster grid which defines the NR RF reference frequency.

Similarly, the NB-IoT raster defines a subset of NB-IoT RF reference frequencies that can be used to identify the RF channel position in the uplink and downlink. The NB-IoT RF reference frequency for an RF channel maps to a mid-point between the middle two subcarriers on the NB-IoT carrier. Hereinafter, the NB-IoT channel raster is referred to as a point on the raster grid which defines the NB-IoT RF reference frequency.

One NR RB in frequency domain consists of <NUM> subcarriers. The number of NR resource blocks may be denoted by Nnr. The NR resource blocks are indexed from <NUM> to (Nnr - <NUM>). The NR subcarriers may be indexed relative to the NR raster. Thus, the NR raster is located on subcarrier with index <NUM>.

The NB-IoT carrier center frequency is denoted by Fnb. The NB-IoT channel raster is <NUM> based. For NR carriers with an even number of RB (Nnr), the channel raster is located at subcarrier index #<NUM> in RB with index <MAT>. For NR carriers with an odd number of RB, channel raster located at subcarrier index #<NUM> in RB with index (Nnr - <NUM>)/<NUM>. The NR RB that contains the NR channel raster is referred to as the middle RB.

Regarding resource block (RB) alignment, in TDD band n41 the channel raster step for NB-IoT is <NUM>, while for NR it is based on the SCS, which is <NUM> in this example. The description of particular embodiments focuses on the case of NR carriers configured with <NUM> subcarrier spacing. Thus, the NR channel raster frequency is given by <NUM>m [kHz], and the NB-IoT channel raster can be expressed as <NUM>n [kHz], with m and n being integers. An example is illustrated in <FIG>.

<FIG> is a frequency diagram illustrating raster steps for NR and NB-IoT in TDD band <NUM>. The horizontal axis represents frequency. As illustrated, the raster step in NR is <NUM> and the raster step in NB-IoT is <NUM>.

In general, while deploying a carrier (NR, LTE, NB-IoT, etc.) the channel raster requirement must be satisfied. Channel raster (or raster) represents a set of possible frequencies for placing the center of a carrier. Most cases use <NUM> raster step, which means the center of the carrier can only be on frequencies <NUM>*n [kHz] (e.g., <NUM>, <NUM>, <NUM>,. An example is illustrated in <FIG>.

<FIG> is a frequency diagram illustrating an example raster grid with a <NUM> step. The horizontal axis represents frequency. An X marks possible locations for NR or LTE channel raster.

NR can have <NUM> channel raster for some TDD bands. For NB-IoT the channel raster is <NUM> but an offset (<NUM> or <NUM>) is allowed from the <NUM> grid. Thus, some constraints (e.g., raster) exist on placing an NB-IoT carrier (cannot place it everywhere). There are limited options for NB-IoT carrier location.

The design of NB-IoT initial access channels (e.g., NPSS, NSSS, and NPBCH) allows a raster offset of <NUM>, -<NUM>, <NUM>, or -<NUM> from the <NUM> raster grid. Thus, an NB-IoT anchor carrier center can be placed at <NUM>n±<NUM> or <NUM>n±<NUM>, where n is an integer. In NB-IoT, the downlink channel raster is located in the center of NB-IoT channel (i.e., the channel center point is located between two NB-IoT subcarriers). Raster offset of ±<NUM> or ±<NUM> is allowed for in-band and guard-band operation modes.

<FIG> is a frequency diagram illustrating alignment of NB-IoT center with the center of an NR RB. As illustrated in <FIG>, to ensure both subcarrier grid and RB alignments between NR and NB-IoT, the NB-IoT carrier center is placed in the middle of an NR RB. Aligning a carrier center frequency of the NB-IoT carrier with the middle of an NR RB means that the NB-IoT carrier and NR RB have the same center frequency. Also, the location of an NB-IoT carrier center must satisfy the raster requirements. <FIG> identifies the suitable NR RBs which can be used for placing an NB-IoT RB.

One example includes an NR carrier with Nnr number of RB. Also, let q (an integer) be the index of an RB in NR relative to the middle RB (which contains NR channel raster) which is used for placing the NB-IoT carrier. In this example, the middle RB is RB index Nnr/<NUM> for even number of RBs, and RB index (Nnr - <NUM>)/<NUM> for odd number of RBs. The middle of each NR RB is between two subcarriers. A goal is to find all feasible values of q (and indexes of NR RBs) that identify NR RBs which can be used for deploying NB-IoT carrier. An example is illustrated in <FIG>.

<FIG> is a frequency diagram illustrating RB indexes relative to the middle NR RBs. Each NR RB may be identified by an index q relative to the middle RB.

For an even number of NR RBs, the frequency of NR RB center with index q is: Fc,RB = <NUM>m + <NUM> + <NUM>q , [kHz]. Note that each RB is <NUM> in15 kHz subcarrier spacing case. An example is illustrated in <FIG>.

<FIG> is a frequency diagram illustrating the location of NR channel raster and the RB center for an even number of NR RBs. As illustrated, the RB center is between subcarriers <NUM> and <NUM>.

The NB-IoT carrier center frequency can be expressed by: <MAT>.

To ensure that the center of NB-IoT carrier is aligned with the center of an NR RB: <MAT> <MAT> or <MAT> or <MAT> or <MAT>.

Which is equivalent to: <MAT> or <MAT> or <MAT> or <MAT>.

Considering the modulo operator represented by z=mod (x, y), where x, y, and z are integers, and z is the remainder after the division of x by y: <MAT>.

The feasible values of q depend on m. That is, q depends on the location of the NR RF reference frequency. Thus, q is determined considering all possible values of m.

Let r be the reminder of m after dividing it by <NUM>: r = mod(m, <NUM>) and r can be any integer value in set {<NUM>,<NUM>,<NUM>,. ,<NUM>, <NUM>}. Solving equation (<NUM>) determines all feasible values of q.

Subsequently, the indexes of suitable NR RBs for placing the NB-IoT carrier are <MAT>. Table <NUM> indicates the feasible NR RBs for deploying NB-IoT considering various locations of NR channel raster (determined by r). Note that the NR channel raster is located on <NUM>m [kHz], and the reminder of m after dividing it by <NUM> is r.

For an odd number of NR RBs, the frequency of NR RB center with index q is: Fc,RB = <NUM>m - <NUM> + <NUM>q, [kHz]. An example is illustrated in <FIG>.

<FIG> is a frequency diagram illustrating the location of NR channel raster and the RB center for an odd number of NR RBS. As illustrated, the NR raster is aligned with subcarrier <NUM>.

Following the similar analysis for the even number of NR RBs: <MAT>.

Solving equation (<NUM>) determines all feasible values of q. Subsequently, the indexes of suitable NR RBs for placing the NB-IoT carrier are <MAT>. Table <NUM> indicates the feasible NR RBs for deploying NB-IoT considering various locations of NR channel raster (determined by r).

Based on the analysis above, feasible locations of an NB-IoT RB for various NR system bandwidths are given below. The number of resources blocks for each NR system bandwidth for <NUM> subcarrier spacing is given in Table <NUM>.

As a particular example, for r = <NUM>, m is divisible by <NUM> and thus the NR channel raster is located on a frequency that is divisible by <NUM>* <NUM> = <NUM>. Therefore, the channel raster is located on a <NUM> grid. In this example, the NB-IoT carrier center can be placed in the middle of NR RBs with the following indexes: <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>.

<FIG> illustrates an example wireless network, according to certain embodiments. Thus, particular embodiments of the wireless network may implement communication standards, such as Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), Long Term Evolution (LTE), New Radio (NR), and/or other suitable <NUM>, <NUM>, <NUM>, or <NUM> standards; wireless local area network (WLAN) standards, such as the IEEE <NUM> standards; and/or any other appropriate wireless communication standard, such as the Worldwide Interoperability for Microwave Access (WiMax), Bluetooth, Z-Wave and/or ZigBee standards.

These components work together to provide network node and/or wireless device functionality, such as providing wireless connections in a wireless network.

In certain embodiments, some or all of the functionality described herein as being provided by a network node, base station, eNB, gNB or other such network device may be performed by processing circuitry <NUM> executing instructions stored on device readable medium <NUM> or memory within processing circuitry <NUM>.

Interface <NUM> is used in the wired or wireless communication of signaling and/or data between network node <NUM>, network <NUM>, and/or WDs <NUM>.

As used herein, wireless device (WD) refers to a device capable, configured, arranged and/or operable to communicate wirelessly with network nodes and/or other wireless devices. Unless otherwise noted, the term WD may be used interchangeably herein with user equipment (UE). Communicating wirelessly may involve transmitting and/or receiving wireless signals using electromagnetic waves, radio waves, infrared waves, and/or other types of signals suitable for conveying information through air.

In some embodiments, a WD may be configured to transmit and/or receive information without direct human interaction. For instance, a WD may be designed to transmit information to a network on a predetermined schedule, when triggered by an internal or external event, or in response to requests from the network.

Examples of a WD include, but are not limited to, a smart phone, a mobile phone, a cell phone, a voice over IP (VoIP) phone, a wireless local loop phone, a desktop computer, a personal digital assistant (PDA), a wireless cameras, a gaming console or device, a music storage device, a playback appliance, a wearable terminal device, a wireless endpoint, a mobile station, a tablet, a laptop, a laptop-embedded equipment (LEE), a laptop-mounted equipment (LME), a smart device, a wireless customer-premise equipment (CPE), a vehicle-mounted wireless terminal device, etc. A WD may support device-to-device (D2D) communication, for example by implementing a 3GPP standard for sidelink communication, vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-everything (V2X) and may in this case be referred to as a D2D communication device.

As yet another specific example, in an Internet of Things (IoT) scenario, a WD may represent a machine or other device that performs monitoring and/or measurements and transmits the results of such monitoring and/or measurements to another WD and/or a network node. The WD may in this case be a machine-to-machine (M2M) device, which may in a 3GPP context be referred to as an MTC device. As one example, the WD may be a UE implementing the 3GPP narrow band internet of things (NB-IoT) standard. Examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances (e.g. refrigerators, televisions, etc.) personal wearables (e.g., watches, fitness trackers, etc.).

In other scenarios, a WD may represent a vehicle or other equipment that is capable of monitoring and/or reporting on its operational status or other functions associated with its operation. A WD as described above may represent the endpoint of a wireless connection, in which case the device may be referred to as a wireless terminal. Furthermore, a WD as described above may be mobile, in which case it may also be referred to as a mobile device or a mobile terminal.

Radio front end circuitry <NUM> is connected to antenna <NUM> and processing circuitry <NUM> and is configured to condition signals communicated between antenna <NUM> and processing circuitry <NUM>.

The benefits provided by such functionality are not limited to processing circuitry <NUM> alone or to other components of WD <NUM>, but are enjoyed by WD <NUM>, and/or by end users and the wireless network generally.

In some embodiments, processing circuitry <NUM> and device readable medium <NUM> may be integrated.

User interface equipment <NUM> is configured to allow input of information into WD <NUM> and is connected to processing circuitry <NUM> to allow processing circuitry <NUM> to process the input information. Using one or more input and output interfaces, devices, and circuits, of user interface equipment <NUM>, WD <NUM> may communicate with end users and/or the wireless network and allow them to benefit from the functionality described herein.

Although the subject matter described herein may be implemented in any appropriate type of system using any suitable components, the embodiments disclosed herein are described in relation to a wireless network, such as the example wireless network illustrated in <FIG>. For simplicity, the wireless network of <FIG> only depicts network <NUM>, network nodes <NUM> and 160b, and WDs <NUM>, 110b, and 110c. In practice, a wireless network may further include any additional elements suitable to support communication between wireless devices or between a wireless device and another communication device, such as a landline telephone, a service provider, or any other network node or end device. Of the illustrated components, network node <NUM> and wireless device (WD) <NUM> are depicted with additional detail. The wireless network may provide communication and other types of services to one or more wireless devices to facilitate the wireless devices' access to and/or use of the services provided by, or via, the wireless network.

<FIG> illustrates an example user equipment, according to certain embodiments. UE <NUM>, as illustrated in <FIG>, is one example of a WD configured for communication in accordance with one or more communication standards promulgated by the <NUM>rd Generation Partnership Project (3GPP), such as 3GPP's GSM, UMTS, LTE, and/or NR standards.

Certain UEs may use all the components shown in <FIG>, or only a subset of the components.

<FIG> is a flowchart illustrating an example method in a wireless device, according to certain embodiments. In particular embodiments, one or more steps of <FIG> may be performed by wireless device <NUM> described with respect to <FIG>. The wireless device may communicate using TDD on a first RAT carrier located within a frequency band of a second RAT.

The method may begin at step <NUM>, where the wireless device (e.g., wireless device <NUM>) receives a first communication on the first RAT carrier. A carrier center frequency of the first RAT carrier aligns with a middle of a RB) of the second RAT. In particular embodiments, the location of the center carrier frequency of the first RAT satisfies raster requirements of the first RAT.

In the invention as claimed, the first RAT uses a <NUM> based channel raster and the second RAT uses a SCS-based channel raster. The second RAT may use <NUM> SCS. The first RAT may be NB-IoT and the second RAT may be <NUM> NR.

In particular embodiments, the first and second RAT may align according to any of the examples and embodiments described above (e.g., with respect to <FIG> and Tables <NUM>-<NUM>).

At step <NUM>, the wireless device the method further comprises transmitting a second communication on the first RAT carrier.

Modifications, additions, or omissions may be made to method <NUM> of <FIG>. Additionally, one or more steps in the method of <FIG> may be performed in parallel or in any suitable order.

<FIG> is a flowchart illustrating an example method in a network node, according to certain embodiments. In particular embodiments, one or more steps of <FIG> may be performed by network node <NUM> described with respect to <FIG>. The network node is configured to communicate using TDD on a first RAT carrier located within a frequency band of a second RAT.

The method begins at step <NUM>, where the network node (e.g., network node <NUM>) transmitting a first communication on the first RAT carrier to a first wireless device. A carrier center frequency of the first RAT carrier aligns with a middle of a RB of the second RAT. In particular embodiments, the location of the center carrier frequency of the first RAT satisfies raster requirements of the first RAT.

At step <NUM>, the network node transmits a second communication on a carrier of the second RAT to a second wireless device. For example, the network node may be communicating with a first wireless device using NB-IoT and a second wireless device using NR.

<FIG> illustrates a schematic block diagram of two apparatuses in a wireless network (for example, the wireless network illustrated in <FIG>). The apparatuses include a wireless device and a network node (e.g., wireless device <NUM> and network node <NUM> illustrated in <FIG>). Apparatuses <NUM> and <NUM> are operable to carry out the example methods described with reference to <FIG> and <FIG>, respectively, and possibly any other processes or methods disclosed herein. It is also to be understood that the methods of <FIG> and <FIG> are not necessarily carried out solely by apparatus <NUM> and/or apparatus <NUM>. At least some operations of the method can be performed by one or more other entities.

Virtual apparatuses <NUM> and <NUM> may comprise processing circuitry, which may include one or more microprocessor or microcontrollers, as well as other digital hardware, which may include digital signal processors (DSPs), special-purpose digital logic, and the like. The processing circuitry may be configured to execute program code stored in memory, which may include one or several types of memory such as read-only memory (ROM), random-access memory, cache memory, flash memory devices, optical storage devices, etc. Program code stored in memory includes program instructions for executing one or more telecommunications and/or data communications protocols as well as instructions for carrying out one or more of the techniques described herein, in several embodiments.

In some implementations, the processing circuitry may be used to cause receiving module <NUM>, determining module <NUM>, transmitting module <NUM>, and any other suitable units of apparatus <NUM> to perform corresponding functions according one or more embodiments of the present disclosure. Similarly, the processing circuitry described above may be used to cause receiving module <NUM>, determining module <NUM>, transmitting module <NUM>, and any other suitable units of apparatus <NUM> to perform corresponding functions according one or more embodiments of the present disclosure.

As illustrated in <FIG>, apparatus <NUM> includes receiving module <NUM> configured to receive transmissions on a particular RAT, according to any of the embodiments and examples described herein. Transmitting module <NUM> is configured to transmit transmissions on a particular RAT, according to any of the embodiments and examples described herein. The RAT may overlap with another RAT according to any of the embodiments and examples described herein.

As illustrated in <FIG>, apparatus <NUM> includes receiving module <NUM> configured to receive transmissions on a particular RAT or RATs, according to any of the embodiments and examples described herein. Transmitting module <NUM> is configured to transmit transmissions on a particular RAT or RATs, according to any of the embodiments and examples described herein. The RATs may overlap according to any of the embodiments and examples described herein.

NFV may be used to consolidate many network equipment types onto industry standard high-volume server hardware, physical switches, and physical storage, which can be located in data centers, and customer premise equipment.

Host computer <NUM> may be under the ownership or control of a service provider or may be operated by the service provider or on behalf of the service provider.

<FIG> illustrates an example host computer communicating via a base station with a user equipment over a partially wireless connection, according to certain embodiments. Example implementations, in accordance with an embodiment of the UE, base station and host computer discussed in the preceding paragraphs will now be described with reference to <FIG>.

Connection <NUM> may be direct, or it may pass through a core network (not shown in <FIG>) of the telecommunication system and/or through one or more intermediate networks outside the telecommunication system.

While OTT connection <NUM> is active, the network infrastructure may further take decisions by which it dynamically changes the routing (e.g., based on load balancing consideration or reconfiguration of the network).

Wireless connection <NUM> between UE <NUM> and base station <NUM> is in accordance with the teachings of the embodiments described throughout this disclosure. One or more of the various embodiments improve the performance of OTT services provided to UE <NUM> using OTT connection <NUM>, in which wireless connection <NUM> forms the last segment. More precisely, the teachings of these embodiments may improve the signaling overhead and reduce latency, and thereby provide benefits such as reduced user waiting time, better responsiveness and extended battery life.

A measurement procedure may be provided for monitoring data rate, latency and other factors on which the one or more embodiments improve. In embodiments, sensors (not shown) may be deployed in or in association with communication devices through which OTT connection <NUM> passes; the sensors may participate in the measurement procedure by supplying values of the monitored quantities exemplified above or supplying values of other physical quantities from which software <NUM>, <NUM> may compute or estimate the monitored quantities.

Additionally, or alternatively, in step <NUM>, the UE provides user data.

FIGURE <NUM> is a flowchart illustrating a method implemented in a communication system, in accordance with one embodiment. For simplicity of the present disclosure, only drawing references to FIGURE <NUM> will be included in this section.

Modifications, additions, or omissions may be made to the systems and apparatuses disclosed herein without departing from the scope of the invention. The components of the systems and apparatuses may be integrated or separated. Moreover, the operations of the systems and apparatuses may be performed by more, fewer, or other components. Additionally, operations of the systems and apparatuses may be performed using any suitable logic comprising software, hardware, and/or other logic. As used in this document, "each" refers to each member of a set or each member of a subset of a set.

Modifications, additions, or omissions may be made to the methods disclosed herein without departing from the scope of the invention. The methods may include more, fewer, or other steps. Additionally, steps may be performed in any suitable order.

The foregoing description sets forth numerous specific details. It is understood, however, that embodiments may be practiced without these specific details. In other instances, well-known circuits, structures and techniques have not been shown in detail in order not to obscure the understanding of this description. Those of ordinary skill in the art, with the included descriptions, will be able to implement appropriate functionality without undue experimentation.

Although this disclosure has been described in terms of certain embodiments, alterations and permutations of the embodiments will be apparent to those skilled in the art. Accordingly, the above description of the embodiments does not constrain this disclosure. Other changes, substitutions, and alterations are possible without departing from the scope of this disclosure, as defined by the claims below.

Claim 1:
A method (<NUM>) performed by a network node for communicating using time division duplexing, TDD, on a first radio access technology, RAT, carrier located within a frequency band of a second RAT, the method comprising:
transmitting (<NUM>) a first communication on the first RAT carrier to a first wireless device, wherein a carrier center frequency of the first RAT carrier aligns with a middle of a resource block, RB, of the second RAT, and wherein the first RAT uses a <NUM> based channel raster and the second RAT uses a subcarrier spacing, SCS, based channel raster.