Patent Description:
The subject matter disclosed herein relates generally to wireless communications and more particularly relates to determining a location of a frequency-domain resource block using frequency spacing values.

The following abbreviations and acronyms are herewith defined, at least some of which are referred to within the following description.

Third Generation Partnership Project ("3GPP"), Access and Mobility Management Function ("AMF"), Carrier Aggregation ("CA"), Clear Channel Assessment ("CCA"), Control Channel Element ("CCE"), Channel State Information ("CSI"), Common Search Space ("CSS"), Downlink Control Information ("DCI"), Downlink ("DL"), Enhanced Clear Channel Assessment ("eCCA"), Enhanced Mobile Broadband ("eMBB"), Evolved Node B ("eNB"), European Telecommunications Standards Institute ("ETSI"), Frequency Division Duplex ("FDD"), Frequency Division Multiple Access ("FDMA"), Hybrid Automatic Repeat Request ("HARQ"), Internet-of-Things ("IoT"), Licensed Assisted Access ("LAA"), Load Based Equipment ("LBE"), Long Term Evolution ("LTE"), LTA Advanced ("LTE-A"), Medium Access Control ("MAC"), Multiple Access ("MA"), Modulation Coding Scheme ("MCS"), Machine Type Communication ("MTC"), Massive MTC ("mMTC"), Master Information Block ("MIB"), Multiple Input Multiple Output ("MIMO"), Multipath TCP ("MPTCP"), Multi User Shared Access ("MUSA"), Narrowband ("NB"), Network Function ("NF"), Next Generation Node B ("gNB"), Physical Broadcast Channel ("PBCH"), Policy Control Function ("PCF"), Primary Synchronization Signal ("PSS"), Quality of Service ("QoS"), Quadrature Phase Shift Keying ("QPSK"), Radio Resource Control ("RRC"), Receive ("RX"), Resource Block ("RB"), Signal-to-Noise Ratio ("SNR"), Synchronization Signal ("SS"), Secondary Synchronization Signal ("SSS"), Scheduling Request ("SR"), Session Management Function ("SMF"), System Information Block ("SIB"), Transport Block ("TB"), Transport Block Size ("TBS"), Transmission Control Protocol ("TCP"), Time-Division Duplex ("TDD"), Time Division Multiplex ("TDM"), Transmission and Reception Point ("TRP"), Transmit ("TX"), Uplink Control Information ("UCI"), User Datagram Protocol ("UDP"), User Entity/Equipment (Mobile Terminal) ("UE"), Uplink ("UL"), Universal Mobile Telecommunications System ("UMTS"), Ultra-reliability and Low-latency Communications ("URLLC"), and Worldwide Interoperability for Microwave Access ("WiMAX").

In a mobile communication network, a channel raster is a set of equally spaced frequency locations in a given frequency band where a carrier frequency (i.e. a center of a channel bandwidth) can be placed. Moreover, a synchronization signal raster is a set of equally spaced frequency locations where a center of SS can be placed. <CIT> describes frequency resource allocation for a narrow-band cellular internet of things system, this includes identifying a first group of tones based at least in part on an interference level between the first group of tones and a second set of wideband tones for wireless communications on a second wireless communications network. <NPL> and describes frame structure with a focus on frequency-domain.

Claim <NUM> defines a method in a user equipment, claim <NUM> defines an apparatus, and claim <NUM> defines apparatus in a mobile communication network.

This code may be provided to a processor of a general-purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the schematic flowchart diagrams and/or schematic block diagrams.

The code may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other devices to produce a computer implemented process such that the code which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the schematic flowchart diagrams and/or schematic block diagram.

<FIG> depicts a wireless communication system <NUM> for determining a location of a frequency-domain resource block using frequency spacing values, according to embodiments of the disclosure. In one embodiment, the wireless communication system <NUM> includes at least one remote unit <NUM>, an access network <NUM> containing at least one base unit <NUM>, wireless communication links <NUM>, and a mobile core network <NUM>. Even though a specific number of remote units <NUM>, access networks <NUM>, base units <NUM>, wireless communication links <NUM>, and mobile core networks <NUM> are depicted in <FIG>, one of skill in the art will recognize that any number of remote units <NUM>, access networks <NUM>, base units <NUM>, wireless communication links <NUM>, and mobile core networks <NUM> may be included in the wireless communication system <NUM>. In another embodiment, the access network <NUM> contains one or more WLAN (e.g., Wi-Fi™) access points.

In one implementation, the wireless communication system <NUM> is compliant with the fifth generation ("<NUM>") system specified in the 3GPP specifications (e.g., "<NUM> NR"). More generally, however, the wireless communication system <NUM> may implement some other open or proprietary communication network, for example, LTE or WiMAX, among other networks.

In one embodiment, the remote units <NUM> may include computing devices, such as desktop computers, laptop computers, personal digital assistants ("PDAs"), tablet computers, smart phones, smart televisions (e.g., televisions connected to the Internet), smart appliances (e.g., appliances connected to the Internet), set-top boxes, game consoles, security systems (including security cameras), vehicle on-board computers, network devices (e.g., routers, switches, modems), or the like. The remote units <NUM> may communicate directly with one or more of the base units <NUM> via uplink ("UL") and downlink ("DL") communication signals. Furthermore, the UL and DL communication signals may be carried over the wireless communication links <NUM>.

The base units <NUM> may be distributed over a geographic region. In certain embodiments, a base unit <NUM> may also be referred to as an access terminal, an access point, a base, a base station, a Node-B, an eNB, a gNB, a Home Node-B, a relay node, a device, or by any other terminology used in the art. The base units <NUM> are generally part of a radio access network ("RAN"), such as the access network <NUM>, that may include one or more controllers communicably coupled to one or more corresponding base units <NUM>. These and other elements of the radio access network are not illustrated, but are well known generally by those having ordinary skill in the art. The base units <NUM> connect to the mobile core network <NUM> via the access network <NUM>.

The base units <NUM> may serve a number of remote units <NUM> within a serving area, for example, a cell or a cell sector via a wireless communication link <NUM>. The base units <NUM> may communicate directly with one or more of the remote units <NUM> via communication signals. Generally, the base units <NUM> transmit downlink ("DL") communication signals to serve the remote units <NUM> in the time, frequency, and/or spatial domain. Furthermore, the DL communication signals may be carried over the wireless communication links <NUM>. The wireless communication links <NUM> may be any suitable carrier in licensed or unlicensed radio spectrum. The wireless communication links <NUM> facilitate communication between one or more of the remote units <NUM> and/or one or more of the base units <NUM>.

In one embodiment, the mobile core network <NUM> is a <NUM> core ("5GC") or the evolved packet core ("EPC"), which may be coupled to other data network <NUM>, like the Internet and private data networks, among other data networks. Each mobile core network <NUM> belongs to a single public land mobile network ("PLMN").

The mobile core network <NUM> includes several network functions ("NFs"). As depicted, the mobile core network <NUM> includes an access and mobility management function ("AMF") <NUM>, a session management function ("SMF") <NUM>, and a user plane function ("UPF") <NUM>. Although a specific number of AMFs <NUM>, SMFs <NUM>, and UPFs <NUM> are depicted in <FIG>, one of skill in the art will recognize that any number of AMFs <NUM>, SMFs <NUM>, and UPFs <NUM> may be included in the mobile core network <NUM>.

The AMF <NUM> provides services such as UE registration, UE connection management, and UE mobility management. The SMF <NUM> manages the data sessions of the remote units <NUM>, such as a PDU session. The UPF <NUM> provides user plane (e.g., data) services to the remote units <NUM>. A data connection between the remote unit <NUM> and a data network <NUM> is managed by a UPF <NUM>.

The access network <NUM> supports a larger minimum channel bandwidth (e.g., <NUM>) than the minimum channel bandwidth of LTE (<NUM>). Accordingly, the base units <NUM> may transmit a wider (e.g., larger bandwidth) SS than the transmission bandwidth of LTE PSS and SSS (e.g., <NUM> including guard subcarriers). For a given subcarrier spacing of SS and a given per-subcarrier signal-to-noise ratio ("SNR"), a wider transmission bandwidth of SS with a longer sequence results in better SS detection performance because of lower cross-correlation among SS sequences and higher spreading gain. Furthermore, wideband SS (e.g., the transmission bandwidth of which is larger than <NUM> for <NUM> subcarrier spacing in frequency bands below <NUM>) is necessary to provide a certain minimum relative timing accuracy with respect to symbol duration, if a larger subcarrier spacing (e.g., <NUM> or <NUM>) is configured for data/control channels.

In some embodiments, the base unit <NUM> constructs and transmits a wideband SS suitable to serve mixed traffics with different service requirements and various capabilities. For example, certain remote units <NUM> may be bandwidth limited and only able to receive narrowband SS, such as the conventional LTE PSS/SSS. Such band-limited remote units <NUM> may include low-cost massive machine-type communication ("mMTC") UEs. Additionally, other remote units <NUM> may be capable of receiving wideband SS. Such non-band-limited UEs may include enhanced mobile broadband (eMBB) UEs. To serve both types of remote units, the wideband SS disclosed herein is receivable by both types of remote units, thus providing efficient radio resource utilization.

Moreover, the base unit <NUM> may indicate a reference frequency location, such as a starting, ending, or center of a resource allocation, using the frequency spacing of a channel raster and an SS raster. In certain embodiments, the SS raster is defined with a larger frequency spacing than the frequency spacing of the channel raster.

<FIG> depicts a network architecture <NUM> used for determining a location of a frequency-domain resource block using frequency spacing values, according to embodiments of the disclosure. The network architecture <NUM> may be a simplified embodiment of the wireless communication system <NUM>. As depicted, the network architecture <NUM> includes a UE <NUM> that detects synchronization signals ("SS") transmitted by a gNB <NUM>. Here, the UE <NUM> may be one embodiment of the remote unit <NUM> and the gNB <NUM> may be one embodiment of the base unit <NUM>, described above.

As depicted, the gNB <NUM> broadcasts system information and SS (see block <NUM>). The UE <NUM> performing cell search detects the SS and receives the system information. In some embodiments, the UE <NUM> searches a channel raster and/or SS raster to detect the SS and receive the system information. The UE <NUM> uses the raster frequency spacing in combination with the received system information to identify a reference frequency location, such as a particular resource block. Specifically, the system information may include information elements k and l, where <MAT> <MAT>.

In the above equations, fc is a reference frequency, fs is a frequency location of the detected SS signal, and ΔFc is a frequency spacing for the channel raster, and ΔFs is a frequency spacing for the SS raster. The operator <MAT> in Equations <NUM> and <NUM> denotes rounding the value X to the nearest integer towards minus infinity. The gNB <NUM> identifies the reference frequency fc to indicate to the UE <NUM> and then calculates the values of k and l according to equations <NUM> and <NUM>. The gNB <NUM> includes the values of k and l as information elements in the system information.

Generally, the UE <NUM> is configured with values for ΔFs and ΔFc. In some embodiments, ΔFs is a predefined for the frequency range. Additionally, ΔFc may be predefined per frequency range or may be configured and signaled by the network. For example, the particular value of ΔFc may be based on a spectrum band used by the gNB <NUM> and/or a geographic region where the gNB <NUM> is located.

Upon receiving the information elements k and l, the UE <NUM> determines the reference frequency fc using the following equation: <MAT>.

In some embodiments, the gNB <NUM> allocates a frequency-domain resource to the UE <NUM> by indicating frequency-domain resource unit, (e.g. a resource block ("RB")) using the raster spacing values and the information elements k and l. Moreover, the reference frequency location may indicate a starting or ending RB for the allocation to the UE <NUM>. In one embodiment, the UE <NUM> has an operating bandwidth which is equal to or smaller than a channel bandwidth, with the operating bandwidth being defined in terms of number of RBs with the information elements k and l indicating a starting or ending RB. If a RB bandwidth is a multiple of ΔFc, a starting/ending frequency location of allocated RBs for UE's operating band can be indicated with the above two information elements k and l. If the RB bandwidth is a multiple of <NUM> · ΔFc, a center of the allocated RBs can be indicated with the information elements k and l.

For example, parameters can be set as follows: Δf =<NUM>, ΔFs = <NUM> · Δf=<NUM>, ΔFc = <NUM> · Δf=<NUM>, and <NUM> RB = <NUM> · ΔFc = <NUM> · Δf =<NUM> for the frequency range below <NUM>. This parameter configuration makes a frequency spacing of the SS raster (<NUM>) to be a multiple of the RB bandwidth (<NUM>), which makes it easier to fit the SS within a certain number of RBs. Furthermore, the frequency spacing of the SS raster is larger than the frequency spacing of the channel raster for faster cell search, and yet it is small enough to accommodate wideband SS (e.g. SS bandwidth of <NUM>) in the minimum channel bandwidth (e.g. <NUM>).

The above examples assume that the reference frequency is a frequency location in the serving cell of the UE <NUM>. However, in other embodiments, the reference frequency may be a frequency location in a neighboring cell. Here, the gNB <NUM> may point to a SS location in the neighboring cell. Where the SS raster of the serving cell and the SS raster of the neighboring cell share the same frequency locations, then the gNB <NUM> only needs to signal the information element k, where the UE <NUM> determines the SS frequency location in the neighboring cell using the below equation: <MAT>.

However, if the SS frequency location in the neighboring cell is not a member of the SS raster in the serving cell (but is a member of the channel raster), then the gNB <NUM> must signal both information elements k and l and the UE <NUM> determines the SS frequency location in the neighboring cell (e.g., the reference frequency fc) using Equation <NUM>.

<FIG> depicts one embodiment of a user equipment apparatus <NUM> that may be used for determining a location of a frequency-domain resource block using frequency spacing values, according to embodiments of the disclosure. The user equipment apparatus <NUM> may be one embodiment of the remote unit <NUM> and/or UE <NUM>. Furthermore, the user equipment apparatus <NUM> may include a processor <NUM>, a memory <NUM>, an input device <NUM>, a display <NUM>, and a transceiver <NUM>. In some embodiments, the input device <NUM> and the display <NUM> are combined into a single device, such as a touch screen. In certain embodiments, the user equipment apparatus <NUM> may not include any input device <NUM> and/or display <NUM>.

The processor <NUM> is communicatively coupled to the memory <NUM>, the input device <NUM>, the display <NUM>, and the transceiver <NUM>.

In some embodiments, the processor <NUM> determines a first set of frequency locations within a frequency range. Here, adjacent frequency locations in the first set of frequency locations are spaced with a first spacing value. Additionally, the processor <NUM> determines a second set of frequency locations within the same frequency range. Here, adjacent frequency locations in the second set of frequency locations are spaced with a second spacing value.

The first spacing value is larger than the second spacing value. In one embodiment, the first set of frequency locations is a set of potential locations for detecting a synchronization signal (e.g., a SS raster). In another embodiment, the second set of frequency locations is a set of carrier raster locations within the frequency range (e.g., a channel raster). In certain embodiments, the first and second spacing values depend on a location of the frequency range within a wireless spectrum and/or on a geographical area of operation. In other embodiments, the second spacing value is a network configured value, the transceiver <NUM> receiving the second spacing value from the network.

Having determined the first and second spacing values, the processor <NUM> calculates a location of a frequency-domain resource block within the frequency range using the first spacing value and the second spacing value. For example, the processor <NUM> may use received system information elements in combination with the spacing values to calculate the frequency-domain resource block location. Moreover, the processor <NUM> controls the transceiver <NUM> to communicate (e.g., receive or transmit) data on the frequency-domain resource block using the calculated location of the resource block.

In certain embodiments, the determined location of a frequency-domain resource block is a starting frequency location of a resource allocation to the user equipment apparatus <NUM>. Here, the determined location indicates the beginning resource block ("RB") of the allocation (in order of increasing frequency). In certain embodiments, the determined location of a frequency-domain resource block is an ending frequency location of a resource allocation to the user equipment apparatus <NUM>. Here, the determined location indicates the last resource block ("RB") of the allocation (in order of increasing frequency). In certain embodiments, the processor <NUM> determines a resource allocation based on the location of the frequency-domain resource block, where determined location indicates a center of the allocation.

In some embodiments, the processor <NUM> determines the location of the frequency-domain resource block by determining a resource block index for the frequency-domain resource block. In such embodiments, communicating data on the frequency-domain resource block includes the transceiver communicating data on the frequency-domain resource block using the location of the determined resource block index. For example, the transceiver <NUM> may receive data from the base unit on the indicated frequency-domain resource block.

In some embodiments, the processor <NUM> (in conjunction with the transceiver <NUM>) detects a synchronization signal ("SS") at a first frequency location in the first set of frequency locations. Moreover, the processor <NUM> may further control the transceiver <NUM> to receive a wideband SS burst with a wideband receiver <NUM>. The wideband SS burst includes a first narrowband SS burst and an additional SS burst in frequency.

The base unit <NUM> (e.g., a gNB) transmits the wideband SS burst with a first periodicity. Accordingly, the transceiver <NUM> receives the wideband SS burst according to the first periodicity. In some embodiments, the transceiver <NUM> further receives the first narrowband SS burst with a second periodicity shorter than the first periodicity. Here, the base unit <NUM> transmits one or more narrowband SS bursts between successive wideband SS bursts.

In certain embodiments, receiving the first narrowband SS burst with the second periodicity includes the transceiver <NUM> receiving a modified first narrowband SS burst whenever the first narrowband SS burst is transmitted without the additional SS burst. In such embodiments, the first narrowband SS burst is modified by (e.g., the base unit <NUM>) applying a different scrambling code to a SS in the first narrowband SS burst and/or applying a cyclical shift to a SS in the first narrowband SS burst. The modified narrowband SS burst is also referred to herein as a "second" narrowband SS burst. In various embodiments, the second (e.g., modified) narrowband SS burst has a higher power spectral density than the first (e.g., non-modified) narrowband SS burst transmitted as part of the wideband SS burst.

In some embodiments, the processor <NUM> detects a cell based on the first narrowband SS burst and/or the wideband SS burst. In certain embodiments, the wideband SS burst includes at least one of: a wideband primary SS ("PSS"), a wideband secondary SS ("SSS"), and a physical broadcast channel ("PBCH") carrying a master information block ("MIB") message. In certain embodiments, the first narrowband SS burst includes at least one of: a narrowband primary SS ("PSS"), a narrowband secondary SS ("SSS"), and a physical broadcast channel ("PBCH") carrying a master information block ("MIB") message.

In certain embodiments, the processor <NUM> further decodes system information from a broadcast channel. Moreover, the processor <NUM> may determine a frequency offset from the system information. In such embodiments, determining the location of the frequency-domain resource block includes using the frequency offset. Specifically, the frequency offset may be calculated by the equation: ΔF<NUM>·k+ΔF<NUM>·l, where ΔF<NUM> is the first spacing value, ΔF<NUM> is the second spacing value, and k and l are information elements included in the system information. Here, the reference frequency is a location the frequency offset away from the frequency on which SS (or the broadcast channel) is received.

In some embodiments, the memory <NUM> stores data relating to determining a location of a frequency-domain resource block using frequency spacing values. For example, the memory <NUM> may store channel raster information, SS raster information, system information, and the like. In certain embodiments, the memory <NUM> also stores program code and related data, such as an operating system or other controller algorithms operating on the user equipment apparatus <NUM> and one or more software applications.

The transceiver <NUM> communicates with one or more base units <NUM> in a mobile communication network. Via a base unit <NUM>, the transceiver <NUM> may communicate with one or more network functions in the mobile communication network. The transceiver <NUM> operates under the control of the processor <NUM> to transmit messages, data, and other signals and also to receive messages, data, and other signals. For example, the processor <NUM> may selectively activate the transceiver (or portions thereof) at particular times in order to send and receive messages. As depicted, the transceiver <NUM> may include one or more narrowband transmitters <NUM> and one or more narrowband receivers <NUM>. The transceiver <NUM> may also include one or more wideband transmitters <NUM> and one or more wideband receivers <NUM>. Additionally, the transceiver <NUM> may support one or more network interfaces <NUM> for communicating with the base unit <NUM> and the mobile core network <NUM>.

<FIG> depicts one embodiment of a base station apparatus <NUM> that may be used for determining a location of a frequency-domain resource block using frequency spacing values, according to embodiments of the disclosure. The base station apparatus <NUM> may be one embodiment of the base unit <NUM> and/or gNB <NUM>. Furthermore, the base station apparatus <NUM> may include a processor <NUM>, a memory <NUM>, an input device <NUM>, a display <NUM>, and a transceiver <NUM>. In some embodiments, the input device <NUM> and the display <NUM> are combined into a single device, such as a touch screen. In certain embodiments, the base station apparatus <NUM> may not include any input device <NUM> and/or display <NUM>.

In some embodiments, the processor <NUM> identifies a first set of frequency locations within a frequency range. In one embodiment, the first set of frequency locations is a set of potential locations for the remote unit <NUM> to detect a synchronization signal. Adjacent frequency locations in the first set of frequency locations are spaced with a first spacing value, ΔF<NUM>. The first set of frequency locations and the first spacing value may depend on a location of the frequency range within a wireless spectrum and/or on a geographical area of operation.

Additionally, the processor <NUM> identifies a second set of frequency locations within the same frequency range. In one embodiment, the second set of frequency locations is a set of carrier raster locations within the frequency range. Adjacent frequency locations in the second set of frequency locations are spaced with a second spacing value. The first spacing value is larger than the second spacing value.

In certain embodiments, the second set of frequency locations and the second spacing value may depend on a location of the frequency range within a wireless spectrum and/or on a geographical area of operation. In other embodiments, the second spacing value is a network configured value. Here, the processor <NUM> controls the transceiver <NUM> to send the second spacing value to the remote unit <NUM>.

The combination of first spacing value and second spacing value are used to indicate a location of a frequency-domain resource block within the frequency range. The transceiver <NUM> receives data from the remote unit <NUM> on the resource block. In some embodiments, the first spacing value and second spacing value are used to indicate a starting location of the frequency-domain resource block. In other embodiments, the first spacing value and second spacing value are used to indicate an ending location of the frequency-domain resource block. In yet other embodiments, the first spacing value and second spacing value are used to indicate a resource block index for the frequency-domain resource block.

In certain embodiments, the processor <NUM> provides (e.g., to the remote unit <NUM>) information elements for determining the location of a frequency-domain resource block using the system information. The remote unit <NUM> then decodes system information from a broadcast channel to determine the location of the frequency-domain resource block. In such embodiments, indicating the target frequency location includes using the frequency offset. Specifically, the frequency offset may be calculated by the equation: ΔF<NUM>·k+ΔF<NUM>·l, where ΔF<NUM> is the first spacing value (e.g., the SS raster spacing value), ΔF<NUM> is the second spacing value (e.g., the channel raster spacing value), and k and l are information elements included in the system information. In one embodiment, the frequency offset is applied to the frequency on which the system information is transmitted to yield the target frequency. Here, the processor <NUM> selects the values of k and l needed to indicate the target frequency location, for example using Equations <NUM> and <NUM>.

In some embodiments, the processor <NUM> (in conjunction with the transceiver <NUM>) transmits a synchronization signal ("SS") at a first frequency location in the first set of frequency locations. Moreover, the processor <NUM> may further control the transceiver <NUM> to transmit a wideband SS burst. Here, the wideband SS burst includes a first narrowband SS burst and an additional SS burst in frequency.

In certain embodiments, the processor <NUM> controls the transceiver <NUM> to transmit the wideband SS burst with a first periodicity. In some embodiments, the transceiver <NUM> further controls the transceiver <NUM> to transmit the first narrowband SS burst with a second periodicity shorter than the first periodicity. Accordingly, the transceiver <NUM> transmits one or more narrowband SS bursts between successive wideband SS bursts.

In certain embodiments, transmitting the first narrowband SS burst includes the processor <NUM> modifying the first narrowband SS burst to form a second narrowband SS burst. In such embodiments, the transceiver <NUM> transmits the second (e.g., modified) narrowband SS burst whenever the narrowband SS burst is transmitted without the additional SS burst (e.g., whenever not part of the wideband SS burst). For example, if the second periodicity is half the value of the first periodicity, the then transceiver <NUM> transmits the wideband SS burst containing the first (unmodified) narrowband SS burst, then transmits the second (modified) narrowband burst without the additional SS burst, again transmits the wideband SS burst containing the first narrowband SS burst, etc..

In some embodiments, the processor <NUM> modifies the first narrowband SS burst by applying a different scrambling code to a SS in the first narrowband SS burst and/or by applying a cyclical shift to a SS in the first narrowband SS burst. In various embodiments, the second (e.g., modified) narrowband SS burst has a higher power spectral density than the first (e.g., non-modified) narrowband SS burst transmitted as part of the wideband SS burst. In certain embodiments, the wideband SS burst includes at least one of: a wideband primary SS ("PSS"), a wideband secondary SS ("SSS"), and a physical broadcast channel ("PBCH") carrying a master information block ("MIB") message. In certain embodiments, the first narrowband SS burst includes at least one of: a narrowband primary SS ("PSS"), a narrowband secondary SS ("SSS"), and a physical broadcast channel ("PBCH") carrying a master information block ("MIB") message.

In some embodiments, the memory <NUM> stores data relating to determining a location of a frequency-domain resource block using frequency spacing values. For example, the memory <NUM> may store channel raster information, SS raster information, system information, and the like. In certain embodiments, the memory <NUM> also stores program code and related data, such as an operating system or other controller algorithms operating on the base station apparatus <NUM> and one or more software applications.

The transceiver <NUM> communicates with one or more remote units <NUM> operating in a mobile communication network. The transceiver may also communicate with one or more network functions in the mobile communication network. The transceiver <NUM> operates under the control of the processor <NUM> to transmit messages, data, and other signals and also to receive messages, data, and other signals. For example, the processor <NUM> may selectively activate the transceiver (or portions thereof) at particular times in order to send and receive messages. As depicted, the transceiver <NUM> may include one or more narrowband transmitters <NUM> and one or more narrowband receivers <NUM>. The transceiver <NUM> may also include one or more wideband transmitters <NUM> and one or more wideband receivers <NUM>. Additionally, the transceiver <NUM> may support one or more network interfaces <NUM> for communicating with the remote unit <NUM> and/or the mobile core network <NUM>.

<FIG> depicts a frequency resource grid <NUM> which may be used in a <NUM> radio network for determining a location of a frequency-domain resource block using frequency spacing values, according to embodiments of the disclosure. The resource grid <NUM> includes a plurality of subcarriers over the frequency range <NUM> (e.g., a frequency band), the subcarriers grouped into resource blocks. <FIG> depicts a channel raster <NUM>, a set of equally spaced frequency locations in the frequency range <NUM> where a carrier frequency (e.g., a center of a channel bandwidth) may be placed. The frequency-spacing value (e.g., the difference between adjacent frequencies) for the channel raster <NUM> is depicted as ΔF<NUM> <NUM>.

<FIG> further depicts a synchronization signal ("SS") raster <NUM>, a set of equally spaced frequency locations in the frequency range <NUM> where the center of a synchronization signal (e.g., PSS or SSS) may be placed. The frequency-spacing value (e.g., the difference between adjacent frequencies) for the SS raster <NUM> is depicted as ΔF<NUM> <NUM>. Here, the SS raster <NUM> has a larger frequency spacing than the frequency spacing of the channel raster <NUM>, this facilitating faster cell search (e.g., ΔF<NUM> > ΔF<NUM>). Moreover, the SS raster <NUM> is sparser than the channel raster <NUM>.

As depicted, the SS raster <NUM> is a subset of the channel raster <NUM>. As such, each frequency location in the SS raster <NUM> is also a frequency location in the channel raster <NUM>. However, in other embodiments the SS raster <NUM> is not a subset of the channel raster <NUM>. Moreover, in certain embodiments the center of a synchronization signal may not coincide with the center of the channel bandwidth (e.g., a frequency location of the carrier frequency), regardless of whether or not the SS raster is a subset of the channel raster. Further, possible relative locations of SS with respect to the carrier frequency within the channel bandwidth may change based on the placement of the carrier frequency.

The detail view <NUM> shows the relationship between the SS raster <NUM> and the channel raster <NUM> in greater detail, also depicted is a subcarrier frequency-spacing value (depicted as ΔF) <NUM>. The subcarrier spacing may also be referred to as the "numerology" for the frequency range <NUM> and the subcarrier frequency-spacing value <NUM> may depend on a frequency band in which the frequency range <NUM> is located. For example, subcarriers spacing of <NUM>, <NUM>, and <NUM> for frequency bands below <NUM> and subcarrier spacing of <NUM>, <NUM>, and <NUM> for frequency bands above <NUM>.

As discussed above, the combination of the channel raster frequency-spacing value <NUM> and the SS raster frequency-spacing value <NUM> may be used to indicate a reference frequency location. Also, the gNB <NUM> may include two information elements k and l in the MIB, where k and l are used along with the frequency-spacing values <NUM> and <NUM> to define the reference frequency location, for example using Equations <NUM> or <NUM>. Recall that the channel raster frequency-spacing value <NUM> and the SS raster frequency-spacing value <NUM> are used as multipliers of k and l to define the reference frequency location.

Note that setting the channel raster frequency-spacing value <NUM> and the SS raster frequency-spacing value <NUM> as multiples of the subcarrier frequency-spacing value <NUM> provides full-flexibility of channel deployment for the configured channel raster <NUM>. For example, if the channel raster frequency-spacing value <NUM> is <NUM> and the SS raster frequency-spacing value <NUM> is <NUM>, but the subcarrier frequency-spacing value <NUM> is <NUM>, then in this scenario there are some frequency locations in the channel raster <NUM> that may not be usable due to frequency distances between the center of synchronization signal and carrier frequencies not being multiples of subcarrier spacing.

In contrast, if the channel raster frequency-spacing value <NUM> is <NUM>, the SS raster frequency-spacing value <NUM> is <NUM>, and the subcarrier frequency-spacing value <NUM> is <NUM>, then in this scenario there all frequency locations in the channel raster <NUM> are multiples of subcarrier spacing away from the center of synchronization signal. In certain embodiments, the UE <NUM> is configured to apply fractional frequency shifting (i.e. frequency shifting of a fraction of subcarrier spacing) so that all frequency locations in the channel raster <NUM> are usable despite the channel raster frequency-spacing value <NUM> and/or the SS raster frequency-spacing value <NUM> not being a multiple of the subcarrier frequency-spacing value <NUM>.

The reference frequency location may be a carrier frequency, a center location of the UE's operating band, a starting frequency location of the UE's operating band, an ending frequency location of the UE's operating band, or a center of SS for a neighboring cell. Alternatively, the reference frequency location may be reference point for determining a center resource block among a set of resource blocks.

In various embodiments, the gNB <NUM> indicates the meaning of the reference frequency (e.g., what the reference frequency location references) or indicates the reference frequency in a pre-defined field of a message, wherein the pre-defined field of the message is associated with the meaning of the reference frequency. This indication may be communicated via a broadcast channel (e.g., via MIB), as downlink control information ("DCI") in a downlink physical control channel (e.g., PDCCH), or via a common (or dedicated) higher-layer signaling (e.g., via RRC signaling).

<FIG> and <FIG> depict wideband SS designs, according to embodiments of the disclosure. <FIG> depicts a wideband SS design <NUM> having two sequences, while <FIG> depicts a wideband SS design <NUM> having three sequences.

As shown in <FIG>, embodiments of the disclosure include a wideband SS design <NUM> having two Zadoff-Chu sequences, a first (narrowband) sequence <NUM> whose frequency range includes the SS raster frequency <NUM> and an additional (second) sequence split into a first part <NUM> and a second part <NUM>. Here, the additional sequence is formed from a single, longer Zadoff-Chu sequence and split into two parts. Guard subcarriers exist between the first sequence <NUM> and the first part <NUM> and also between the first sequence <NUM> and the second part <NUM>.

As depicted, the first part <NUM> may be located on (e.g., mapped to) frequencies above the first sequence <NUM> and the second part <NUM> may be located on (e.g., mapped to) frequencies below the first sequence <NUM>. In one embodiment, the first part <NUM> of the additional sequence is mapped to a first frequency band with respect to the frequency location of the first (base) sequence <NUM>, while the second part <NUM> of the additional sequence is mapped to a second frequency band with respect to the frequency location of the first sequence <NUM>. In another embodiment, the additional sequence (as a whole) is circularly mapped to a first frequency band residing above the frequency location of the first sequence <NUM> to form the first part <NUM>, while the second part <NUM> is circularly mapped to a second frequency band residing below (e.g., at lower frequencies) the frequency location of the first sequence <NUM> to form the second part <NUM>.

The combination of the first sequence <NUM> and additional sequence (e.g., first part <NUM> and second part <NUM>) form a wideband SS receivable by a eMBB UE using a wideband receiver. Moreover, the first sequence <NUM> alone is receivable as a narrowband SS using a narrowband receiver. Note that the wideband SS design <NUM> includes sufficient guard bands between the first sequence <NUM> and the first part <NUM> and also between the first sequence <NUM> and the second part <NUM> for operation of the narrowband receiver. Accordingly, both wideband and band-limited UEs are able to receive the same SS signal and perform cell detection using the wideband SS design <NUM>.

As shown in <FIG>, other embodiments of the disclosure include a wideband SS design <NUM> having three sequences, the first (narrowband) sequence <NUM> whose frequency range includes the SS raster frequency <NUM>, a second sequence <NUM>, and a third sequence <NUM>. The second sequence <NUM> and third sequence <NUM> are distinct Zadoff-Chu sequences, while the first part <NUM> and second part <NUM> are portions of the same, longer Zadoff-Chu sequence. Guard subcarriers exist between the first sequence <NUM> and the second sequence <NUM> and also between the first sequence <NUM> and the third sequence <NUM>.

As depicted, the second sequence <NUM> may be located on frequencies above the first sequence <NUM>, while the third sequence <NUM> may be located on frequencies below the first sequence <NUM>. In other embodiments, the second sequence <NUM> may be located on frequencies below the first sequence <NUM>, while the third sequence <NUM> may be located on frequencies above the first sequence <NUM>. The combination of the first sequence <NUM>, second sequence <NUM>, and third sequence <NUM> form a wideband SS receivable using a wideband receiver. Note that the wideband SS design <NUM> includes sufficient guard bands between the first sequence <NUM> and the second sequence <NUM> and also between the first sequence <NUM> and the third sequence <NUM> for operation of the narrowband receiver.

The wideband SS designs <NUM>, <NUM> support both band-limited UEs and enhanced mobile broadband UEs due to the inclusion of multiple sequences. A band-limited UE performs cell detection using the first sequence <NUM> which is designed and located to be receivable by a narrowband receiver. On the other hand, enhanced mobile broadband UEs (or other non-band-limited UEs) having a wideband receiver perform cell detection using the concatenated sequences (e.g., the first sequence <NUM> concatenated with either the first and second parts <NUM>, <NUM> or the second sequence <NUM> and third sequence <NUM>).

The first sequence <NUM> is transmitted (e.g., by the gNB <NUM>) within a sub-band <NUM>. In the depicted embodiments, the sub-band <NUM> is centered on the SS raster frequency location <NUM> (e.g., the center of the sub-band <NUM> corresponds to the SS raster frequency location <NUM>). In certain embodiments, the bandwidth of the sub-band <NUM> may be determined by the minimum operating bandwidth capability of the band-limited UEs.

The wideband SS designs <NUM>, <NUM> beneficially support both bandwidth limited UEs and normal (non-bandwidth limited) UEs without performance degradation, as shown below with reference to <FIG>. In sum, the wideband SS designs <NUM>, <NUM> significantly outperform conventional LTE PSS in missed detection probability performance and the multi-sequence concatenation based wideband PSS performs comparably to a single-long sequence based wideband PSS.

Table <NUM> shows example parameters for a two-sequence synchronization signal transmitted with the bandwidth wider than conventional LTE PSS/SSS bandwidth, such as the wideband SS design <NUM>. Here, the transmission bandwidth of a wideband SS burst may be fixed in the frequency range and may additionally have predefined subcarrier spacing per frequency range. In some embodiments, the transmission bandwidth may change over different frequency ranges, such that different predefined subcarrier spacing values are associated with different frequency ranges.

Table <NUM> shows example parameters for a three-sequence synchronization signal transmitted with the bandwidth wider than conventional LTE PSS/SSS bandwidth, such as the wideband SS design <NUM>. Again, the transmission bandwidth of a wideband SS burst may be fixed in the frequency range and may additionally have predefined subcarrier spacing per frequency range. Moreover, the transmission bandwidth may change over different frequency ranges, such that different predefined subcarrier spacing values are associated with different frequency ranges.

Note that Tables <NUM> and <NUM> assume that one resource block ("RB") is equal to <NUM> subcarriers and frequency and one OFDM symbol duration in time. Here, the first sequence <NUM> is placed within six RBs (covering <NUM> subcarriers or <NUM> bandwidth) and the SS is transmitted within <NUM> RBs (covering <NUM> subcarriers or <NUM> bandwidth). As the sequence lengths are less than the number of allocated subcarriers (e.g., <NUM><<NUM>, (<NUM>+<NUM>)<<NUM>, and (<NUM>+<NUM>+<NUM>)<<NUM>), certain of the allocated subcarriers become guard subcarriers with no information being carried during the synchronization signal.

<FIG> depicts a transmission pattern <NUM> of wideband SS bursts <NUM> and narrowband SS bursts <NUM>, according to embodiments of the invention. In one embodiment, the wideband SS bursts <NUM> are embodiments of the wideband SS design <NUM>. In another embodiment, the wideband SS bursts <NUM> are embodiments of the wideband SS design <NUM>. The wideband SS bursts <NUM> are transmitted centered on a SS raster frequency <NUM>.

The narrowband SS bursts <NUM> may be embodiments of conventional LTE SS bursts, such as a PSS/SSS transmission. The narrowband SS bursts <NUM> are also transmitted centered on the SS raster frequency <NUM>. Here, the narrowband SS burst <NUM> corresponds to a portion of the wideband SS bursts <NUM>. Specifically, the narrowband SS burst <NUM> corresponds to a narrowband SS portion <NUM> of the wideband SS burst, such as the first sequence <NUM> discussed above with reference to <FIG> and <FIG>. As depicted, each wideband SS burst <NUM> includes guard bands <NUM> between the narrowband SS portion <NUM> and the additional SS (here, a first additional SS <NUM> and a second additional SS <NUM>).

Each wideband SS burst <NUM> may include, as content, a wideband PSS, a wideband SSS, and/or physical broadcast channel ("PBCH") carrying a master information block ("MIB") message. Additionally, each narrowband SS burst <NUM> may include a narrowband PSS and a narrowband SSS. In certain embodiments, a narrowband SS burst <NUM> may include a MIB message. Moreover, the narrowband PSS and the narrowband SSS may each correspond to a portion of the wideband PSS and a portion of the wideband SSS, respectively.

In certain embodiments, the gNB <NUM> may transmit a narrowband SS burst <NUM> and a wideband SS burst <NUM> with different periodicities, as depicted in <FIG>. In the depicted embodiments, the wideband SS bursts <NUM> are transmitted with a wideband SS burst periodicity <NUM> of <NUM>. The narrowband SS bursts are transmitted with a narrowband SS burst periodicity <NUM> (<NUM>) which is shorter than the wideband SS burst periodicity <NUM>. Accordingly, transmission of each wideband SS burst <NUM> is interleaved with transmissions of one or more narrowband SS bursts <NUM>.

By transmitting the narrowband SS burst <NUM> and wideband SS burst <NUM> with different periodicities, the gNB <NUM> guarantees similar cell detection latencies for all types of UEs, provides coverage extension benefit for band-limited UEs, while optimizing SS overhead. With this SS transmission structure, the SS monitoring periodicity may depend on the UE type. For example, band-limited UEs may use a <NUM> SS periodicity, while non-band-limited (e.g., "normal") UEs may use a <NUM> SS periodicity. However, in other embodiments the gNB <NUM> may transmit the narrowband SS burst <NUM> and the wideband SS burst <NUM> with the same periodicity.

Because a wider synchronization signal transmission bandwidth with a longer sequence results in better synchronization signal detection performance (e.g., for a given subcarrier spacing of SS and for a given per-subcarrier signal-to-noise ratio ("SNR")), the wideband SS designs <NUM>, <NUM> require fewer instances for non-coherent accumulation in order for a UE to detect a cell. Thus, the wideband SS signal designs <NUM>, <NUM> benefit from sparser transmissions in time than a narrowband SS transmission (e.g., a conventional LTE PSS/SSS transmission). Sparser transmissions in time amount to a longer SS periodicity and beneficially result in reduced SS overhead for a given target-detection latency.

In one embodiment, the PBCH is transmitted only on the wideband SS burst <NUM> (e.g., transmitted with longer periodicity, such as <NUM>). In such embodiments, the gNB <NUM> may transmit repeated PBCH for coverage extension around a slot when the wideband SS burst is transmitted. Moreover, a band-limited UE <NUM> may attempt decoding of PBCH every <NUM> to discover timing of the PBCH transmission occasions. Attempted decodings every <NUM> may also be used to discover the timing of the wideband SS burst occasions. After acquiring timing, the band-limited UE <NUM> attempts decoding of PBCH only when the SS burst with PBCH (e.g., the wideband SS burst) occurs.

In some embodiments, narrowband PSS/SSS in the narrowband SS burst <NUM> are the same as a part of the wideband PSS/SSS in the wideband SS burst <NUM>. In other embodiments, the narrowband SSS in the narrowband SS burst is different than the corresponding portion of the wideband SSS in the wideband SS burst. In such embodiments, the narrowband PSS may be the same as the corresponding part of the wideband PSS.

In one embodiment, the narrowband SSS may be coded with a different scrambling code then the scrambling code used for the corresponding part of the wideband SSS. In another embodiment, the base SSS sequence may be perturbed (e.g., cyclically shifted) differently for the narrowband SSS then for the corresponding part of the wideband SSS. In yet another embodiment, the narrowband SSS may be both perturbed differently than the corresponding part wideband SSS and also coded with a different scrambling code. By coding/perturbing the narrowband SSS differently than the corresponding portion of wideband SSS, the gNB <NUM> provides additional timing information to the UE <NUM>. Moreover, the different scrambling codes and/or perturbation amounts also indicate to the UE <NUM> whether the narrowband SS is part of a wideband SS burst or is a standalone narrowband SS burst.

The particular scrambling codes/sequences on the SSS, or the perturbations of the base SSS sequence, may be based on the slot index and/or the SS burst index. As used herein, the SS burst index indicates a timing offset from the slot where PBCH is transmitted. For example, the SS burst index for the SS burst coinciding with the PBCH is <NUM>, the following SS burst has a SS burst index of <NUM>, and so on until the next SS burst occasion that coincides with PBCH, at which point the SS burst index resets to <NUM>. Note that in the above example, the band-limited UE <NUM> attempts PBCH decoding only when the SS burst index is <NUM>. Moreover, the band-limited UE detecting a portion of the wideband SSS (differentiated from the narrowband SSS by scrambling code or sequence perturbation, as discussed above) may also trigger PBCH decoding.

While <FIG> shows both wideband SS bursts <NUM> and narrowband SS bursts <NUM>, the gNB <NUM> may selectively turn on and off the narrowband SS bursts <NUM> depending on deployment scenarios. For example, if the gNB <NUM> is not supposed to serve band-limited UEs <NUM>, then the gNB <NUM> does not transmit narrowband SS bursts <NUM>, instead transmitting wideband SS bursts <NUM>. As another example, the gNB <NUM> only transmits the narrowband SS bursts <NUM> for a particular duration at a specific time of the day. Here, band-limited UEs <NUM>, such as mMTC UEs, are scheduled to be active during the specific time of the day corresponding to those times when the gNB <NUM> transmits the narrowband SS bursts <NUM>. In a third example, the gNB <NUM> selectively turns on the narrowband SS bursts <NUM> in response to request from a band-limited UE <NUM>. In this example, a band-limited UE <NUM> may initiate side-the communication (e.g., device-to-device communication) with a non-ban-limited UE <NUM> in order to send the gNB <NUM> a request to turn on the narrowband SS bursts <NUM>.

Wideband-capable UEs <NUM> (e.g., eMBB UEs) may perform cell detection by searching for a wideband SS burst <NUM> with a predetermined periodicity (e.g., <NUM>). Once the wideband-capable UEs <NUM> detect the wideband SS burst <NUM>, with acquisition of coarse timing and frequency information, they can discover the narrowband SS bursts <NUM> via network signaling or via blind detection. Using the narrowband SS bursts <NUM>, the UEs <NUM> refine frequency estimation. In certain embodiments, the narrowband SS bursts <NUM> have a higher power spectral density than the wideband SS bursts <NUM>. Here, the higher power spectral density aids band-limited UEs in cell detection.

<FIG> contains a first graph <NUM> and a second graph <NUM>, each illustrating primary synchronization signal missed detection probabilities, according to embodiments of the disclosure. The first graph <NUM> shows various probabilities of a UE missing PSS detection while traveling at <NUM>/h (e.g., at low speed). The first graph <NUM> illustrates the simulation results for link-level performance evaluation of a conventional LTE sequence <NUM>, PSS missed detection probability performance for a single, long sequence (here, L=<NUM>) <NUM>, and PSS missed detection probability performance for three concatenated sequences <NUM>, such as the wideband SS burst described with reference to <FIG> and using parameters discussed in Table <NUM>.

As depicted, both wideband PSSs (having bandwidth approximately four times wider than the LTE PSS) significantly outperform the LTE PSS. For example, at <NUM>% missed detection rate, both the single, long sequence performance <NUM> and the three-concatenated-sequence performance <NUM> show larger than <NUM> dB SNR gains over the conventional LTE performance <NUM>. Moreover, the simulation results show that the three-concatenated-sequence performance <NUM> perform similarly to the single-long sequence performance <NUM>. Note that the cell detection receiver complexity is approximately the same for both wideband PSSs.

The second graph <NUM> shows various probabilities of a UE missing PSS detection while traveling at <NUM>/h (e.g., at high speed). The second graph <NUM> shows PSS missed detection probability performance for the conventional LTE sequence <NUM>, PSS missed detection probability performance for the single, long sequence (here, L=<NUM>) <NUM>, and PSS missed detection probability performance for the three concatenated sequences <NUM>, such as the wideband SS burst described with reference to <FIG> and using parameters discussed in Table <NUM>.

As depicted, both wideband PSSs (having bandwidth approximately four times wider than the LTE PSS) significantly outperform the LTE PSS. For example, at <NUM>% missed detection rate, both the single, long sequence performance <NUM> and the three-concatenated-sequence performance <NUM> show larger than <NUM> dB SNR gains over the conventional LTE performance <NUM>. Moreover, the simulation results show that the three-concatenated-sequence performance <NUM> perform similarly to the single-long sequence performance <NUM>.

Employing single long sequence based wideband SS for both eMBB UEs and band limited (BL) UEs and BL UEs' using a part of wideband SS for cell detection would degrade cell detection performance of BL UEs, because a set of partial sequences extracted from a set of single long sequences have poor auto- and cross-correlation performance, compared to a set of short Zadoff-Chu (ZC) sequences. Beneficially, the two- and three-concatenated sequence wideband signals disclosed herein maintain auto- and cross-correlation performance, while outperforming LTE PSS in missed detection probability performance.

<FIG> depicts a method <NUM> for determining a location of a frequency-domain resource block using frequency spacing values, according to embodiments of the disclosure. In some embodiments, the method <NUM> is performed by an apparatus, such as the remote unit <NUM>, the UE <NUM>, and/or the user equipment apparatus <NUM>. In certain embodiments, the method <NUM> may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method <NUM> begins and determines <NUM> a first set of frequency locations within a frequency range. In certain embodiments, the first set of frequency locations is a set of potential locations for detecting a synchronization signal ("SS"). Here, adjacent frequency locations in the first set of frequency locations are spaced with a first spacing value. In one embodiment, the first spacing value may depend on a location of the frequency range within a wireless spectrum and/or a geographical area of operation.

In certain embodiments, determining <NUM> the first set of frequency locations includes detecting the SS at a first frequency location in the first set of frequency locations. Moreover, detecting the SS may include receiving a wideband SS burst with a wideband receiver. Here, the wideband SS burst is transmitted with a first periodicity and comprises a first narrowband SS burst and an additional SS burst in frequency. In some embodiments, the wideband SS burst comprises at least one of: a wideband primary SS ("PSS"), a wideband secondary SS ("SSS"), and a physical broadcast channel ("PBCH") carrying a master information block ("MIB") message. In certain embodiments, the first narrowband SS burst comprises at least one of: a narrowband PSS, a narrowband SSS, and a PBCH carrying a MIB message. Additionally, determining <NUM> the first set of frequency locations may include detecting a cell based on one of: the first narrowband SS burst, and the wideband SS burst.

In some embodiments, detecting the SS may also include receiving the first narrowband SS burst with a second periodicity shorter than the first periodicity. In certain embodiments, receiving the first narrowband SS burst with a second periodicity shorter than the first periodicity comprises receiving a modified first narrowband SS burst whenever the first narrowband SS burst is transmitted without the additional SS burst. In such embodiments, the first narrowband SS burst may be modified by applying one or more of: a different scrambling code to a SS in the first narrowband SS burst and a cyclical shift to a SS in the first narrowband SS burst. Here, the modified first narrowband SS burst may have a higher power spectral density than the first narrowband SS burst transmitted with the additional SS burst.

The method <NUM> continues and determines <NUM> a second set of frequency locations within the same frequency range. Here, adj acent frequency locations in the second set of frequency locations are spaced with a second spacing value. In certain embodiments, the second set of frequency locations is a set of carrier raster locations within the frequency range. In some embodiments, the first spacing value is larger than the second spacing value.

In one embodiment, the second spacing value may depend on a location of the frequency range within a wireless spectrum and/or a geographical area of operation. In another embodiment, the second spacing value is a network configured value. For example, determining <NUM> the second set of frequency locations may include receiving the second spacing value from the network.

The method <NUM> includes calculating <NUM> a location of a frequency-domain resource using the first and second spacing values. Here, the frequency-domain resource location is determined in response to determining the first and second sets of frequency locations. In some embodiments, the location of the frequency-domain resource block is one of a starting resource block and an ending resource block of an allocation that includes the determined frequency-domain resource block.

In some embodiments, calculating <NUM> the location of the frequency-domain resource block comprises determining a resource block index for the frequency-domain resource block, and wherein communicating data on the frequency-domain resource block comprises communicating data on the frequency-domain resource block using the location of the determined resource block index.

In some embodiments, calculating <NUM> the location of the frequency-domain resource block includes decoding system information from a broadcast channel determining a frequency offset from the system information. In such embodiments, the location of the frequency-domain resource block is determined using the frequency offset. In certain embodiments, the frequency offset is calculated using the equation, ΔF<NUM> · k + ΔF<NUM> · l, where ΔF<NUM> is the first spacing value, ΔF<NUM> is the second spacing value, and k and l are information elements included in the system information.

The method <NUM> includes communicating <NUM> data on the frequency-domain resource block using the calculated location of the resource block. In one embodiment, communicating <NUM> data on the determined frequency-domain resource block includes receiving data from the base unit on the determined location. The method <NUM> ends.

Claim 1:
A method in a user equipment, the method comprising:
determining a first frequency spacing value;
determining a second frequency spacing value;
receiving system information comprising first and second information elements, the first information element indicating a multiplier of the first frequency spacing value, and the second information element indicating a multiplier of the second frequency spacing value;
using the sum of a product of the multiplier of the first frequency spacing value and the first frequency spacing value and a product of the multiplier of the second frequency spacing value and the second frequency spacing value to identify a reference frequency location of a resource block; and communicating data based on the frequency location of the resource block.