Patent Description:
Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems. A wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).

In some cases, a UE may be a low-cost or low-complexity machine type communication (MTC) device that may communicate with a base station in a narrow subband, or narrowband regions, of a system bandwidth of a wireless communications system. Such UEs may be referred to as narrowband devices. Because of the reduced bandwidth available for communications between a base station and narrowband device, some periodic signals provided by the base station may have reduced opportunities for transmission, which may impact some UE operations. For example, a base station may transmit a positioning reference signal (PRS) at a predetermined time period interval, which may be used to determine an accurate position of the UE. In cases where a UE is capable of communications using the full system bandwidth, PRS transmissions may be provided across a PRS bandwidth that may cover the system bandwidth, or cover some portion of the system bandwidth. A narrowband device may, however, be capable of communications using less than the full PRS bandwidth, which may result in fewer PRS transmissions being received at the narrowband device and thus fewer PRS measurements that may be used for position determination.

Reduced PRS measurements at narrowband devices may thus delay position determination for a UE, provide less accurate position for the UE, or both. Accordingly, enhanced efficiency in making PRS measurements in narrowband devices may be desirable in order to provide a relatively accurate position for the UE in a relatively time-efficient manner.

<NPL> relates to enhancements for supporting MTC UEs. <NPL> relates to handling of EPDCCH and PRS collision. <NPL>relates to multiplexing of downlink channels for NB-IoT. <CIT> (<NUM>-<NUM>-<NUM>) discloses methods and apparatus for positioning reference signals (PRS) in a new carrier type (NCT).

Aspects of the present invention are provided in the independent claims. Preferred embodiments are provided in the dependent claims.

In the appended figures, similar components or functions may have the same reference label. Additionally or alternatively, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components.

Various aspects of the present disclosure provide techniques that may assist in the determination of a user equipment (UE) position for a UE operating using a narrowband portion of a system bandwidth. Such position determination may be made using one or more signals transmitted between the UE and a base station, such as one or more downlink signals that may include positioning reference signals (PRS) or other downlink signals (e.g., synchronization signals, physical broadcast channel (PBCH) signals, system information blocks (SIBs), etc.). A UE may make some measurements based at least in part on the received signals, such as observed time difference of arrival (OTDA) measurements, received signal strength indicator (RSSI) measurements, or reference signal time difference (RSTD) measurements, to name a few examples. The UE measurements may be used, in conjunction with known locations of one or more base stations to determine a position of the UE.

For example, the base station, UE, or other apparatus may identify positioning measurements, such as RSTD, RSSI, OTDA, other measurements, or combinations thereof, associated with an unknown location (e.g., from a UE in an unknown location) and estimate a position of the unknown location based at least in part on the positioning measurements associated with the unknown location, and a set of measurements for known locations stored in the database. In an example, the base station, UE, or other device may determine one or more positioning measurements from the set of measurements (for the known location) that may be similar to the identified positioning measurements associated with the unknown location to estimate the position of the unknown location.

As indicated above, some wireless systems may provide service for a category of low-cost or low-complexity UEs known as MTC devices or narrowband devices. These devices may communicate with some restrictions, which may be based at least in part on physical limitations, and which may include lower data rates, limited transport block size, half duplex operation, or relaxed switching time. Low-cost or low-complexity devices may additionally or alternatively be provided or supported with coverage enhancements, and may be configured to operate within a narrowband region of a wideband carrier. In some cases, the carrier may be divided into multiple narrowband regions serving different devices. The reduced bandwidth of such narrowband devices may present challenges to position determination that may be made based at least in part on PRS transmissions, due to the reduced number of PRS transmission opportunities for narrowband devices. Such reduced numbers of PRS transmission opportunities may result from the reduced bandwidth available for narrowband devices, coverage enhancement techniques for such devices (e.g., relatively long bundling may additionally or alternatively limit time resources available for PRS), and/or relatively large cell radius (e.g., <NUM> cell radius) that may result in relatively long round trip delay (RTD) and less accuracy in RTD measurements.

In some examples, a UE may use wideband PRS transmissions that are received in a narrowband portion of a system bandwidth for PRS measurements. In some examples, a UE may determine a resource block (RB) index of a received PRS transmission based at least in part on the wideband region of the base station, which may be different than an RB index of a narrowband RB that includes the PRS transmission. In some examples, a base station may configure PRS resources separately for narrowband devices, such as according to a bandwidth of the narrowband devices or with a single PRS tone per symbol compared to two PRS tones per symbol that may be used for wideband PRS transmissions. Such separately configured PRS resources may be used alone, or in conjunction with other wideband PRS resources or other downlink signals for positioning measurements.

In some examples, in order to additionally or alternatively enhance positioning, additional downlink signals may be used to assist in positioning, such as a synchronization signal or control channel signal, for example. A UE may use non-coherent combining of the additional downlink signals and PRS to determine a power delay profile (PDP), or may use weighted combining of the timing results from PRS measurements based and other downlink channel parameters. In additional examples, a base station may receive one or more uplink signals from a narrowband UE and may perform positioning measurements and determine UE position based at least in part on the received uplink signals from the UE.

Aspects of the disclosure are initially described below in the context of a wireless communication system. Specific examples are then described for positioning resources and techniques for narrowband devices. These and other aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to positioning signals for narrowband devices.

<FIG> illustrates an example of a wireless communications system <NUM> in accordance with various aspects of the present disclosure. The wireless communications system <NUM> includes base stations <NUM>, UEs <NUM>, and a core network <NUM>. In some examples, the wireless communications system <NUM> may be a Long Term Evolution (LTE)/LTE-Advanced (LTE-A) network. The base stations <NUM> and UEs <NUM> may performing positioning determination for UEs <NUM> operating in narrowband portions of a system bandwidth according to various techniques as discussed herein.

Each base station <NUM> may provide communication coverage for a respective geographic coverage area <NUM>. Communication links <NUM> shown in wireless communications system <NUM> may include UL transmissions from a UE <NUM> to a base station <NUM>, or DL transmissions, from a base station <NUM> to a UE <NUM>. A UE <NUM> may additionally or alternatively be referred to as a mobile station, a subscriber station, a remote unit, a wireless device, an access terminal (AT), a handset, a user agent, a client, or like terminology. A UE <NUM> may additionally or alternatively be a cellular phone, a wireless modem, a handheld device, a personal computer, a tablet, a personal electronic device, an machine type communication (MTC) device, etc..

Base stations <NUM> may additionally or alternatively be referred to as eNodeBs (eNBs) <NUM>.

Some types of wireless devices may provide for automated communication. Automated wireless devices may include those implementing Machine-to-Machine (M2M) communication or MTC. Some UEs <NUM> may be MTC devices, additionally or alternatively referred to as narrowband devices, such as those designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical (PHY) access control, and transaction-based business charging. An MTC device may operate using half-duplex (one-way) communications at a reduced peak rate. MTC devices may additionally or alternatively be configured to enter a power saving "deep sleep" mode when not engaging in active communications. In some examples, some MTC devices may be capable of providing position information of the device, such as MTC devices associated with a mobile or movable piece of equipment. Because of the low cost and low complexity that may be desired for such a device, it may be desirable to determine positioning information based at least in part on, for example, a PRS, or other signals, transmitted by base stations <NUM> or UEs <NUM>, in order to avoid having a dedicated positioning module (e.g., a global positioning system (GPS) module). Additionally or alternatively, in some cases a dedicated positioning module may not provide timely or accurate positioning information in some scenarios. Thus, techniques described herein may be used to obtain positioning measurements that may be used in position determination.

LTE systems may utilize OFDMA on the DL and single carrier frequency division multiple access (SC-FDMA) on the UL. OFDMA and SC-FDMA partition the system bandwidth into multiple (K) orthogonal subcarriers, which are commonly referred to as tones or bins. Each subcarrier may be modulated with data. For example, K may be equal to <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> with a subcarrier spacing of <NUM> kilohertz (KHz) for a corresponding system bandwidth (with guardband) of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> megahertz (MHz), respectively. The system bandwidth may additionally or alternatively be partitioned into sub-bands. For example, a sub-band may cover <NUM>, and there may be <NUM>, <NUM>, <NUM>, <NUM> or <NUM> sub-bands.

A frame structure may be used to organize physical resources. A frame may be a <NUM> interval that may additionally or alternatively be divided into <NUM> equally sized subframes. Each sub-frame may include two consecutive time slots. Each slot may include <NUM> or <NUM> OFDMA symbol periods. A resource element (RE) includes one symbol period and one subcarrier (a <NUM> frequency range) which may additionally or alternatively be referred to as a tone. A RB may contain <NUM> consecutive subcarriers in the frequency domain and, for a normal CP in each OFDM symbol, <NUM> consecutive OFDM symbols in the time domain (<NUM> slot), or <NUM> REs. Some REs may include DL reference signals (DL-RS). The DL-RS may include a cell-specific reference signals (CRS) and a UE-specific RS (UE-RS). UE-RS may be transmitted on the RBs associated with physical downlink shared channel (PDSCH). The number of bits carried by each RE may depend on the modulation scheme (the configuration of symbols that may be selected during each symbol period). Thus, the more RBs that a UE receives and the higher the modulation scheme, the higher the data rate may be.

Some base stations <NUM> may utilize a portion of the available DL bandwidth to broadcast multimedia data to some or all UEs <NUM> within the coverage area <NUM>. For example, a wireless communications system may be configured to broadcast mobile TV content, or to multicast live event coverage to UEs <NUM> located near a live event such as a concert or sporting event. In some cases, this may enable more efficient utilization of the bandwidth. These base stations may be referred to as multimedia broadcast multicast service (MBMS) or evolved multimedia broadcast multicast service (eMBMS) cells. In some cases, MBMS cells may be grouped together in a MBMS single frequency network (MBSFN) wherein the broadcast media is transmitted on the same frequency resources by each supporting cell. However, some UEs <NUM> in the coverage area may elect not to receive the MBMS data. In some examples, MBMS data may additionally or alternatively include periodic signals, such as PRS transmissions, that may be used for positioning determination.

<FIG> illustrates an example of a wireless communications system <NUM> for positioning signals for narrowband devices. Wireless communications system <NUM> may include a first base station <NUM>-a, a second base station <NUM>-b, and UE <NUM>-a, which may be examples of the corresponding devices described with reference to <FIG>. Base stations <NUM> may transmit PRS signals, and UE <NUM>-a may receive PRS transmissions, and measurements from such PRS signals may be used to determine position information for the UE <NUM>-a. In some cases, UE <NUM>-a may be a low-cost or low-complexity MTC device.

In some cases, first base station <NUM>-a may transmit a first carrier <NUM>-a that may be divided into multiple narrowband regions serving different devices, and UE <NUM>-a may operate in a narrowband region <NUM>-a (e.g., a <NUM> region) within the frequency range of carrier <NUM>-a (e.g., a <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> band). Similarly, second base station <NUM>-b may transmit a second carrier <NUM>-b that may be divided into multiple narrowband regions serving different devices, and UE <NUM>-a may operate in a narrowband region <NUM>-b within the frequency range of carrier <NUM>-b. In some examples, the narrowband region <NUM>-b may not be in-band with wideband transmissions, but may be located in a standalone frequency band that is separate from the wideband bandwidth, or may be located in a guard band of the wideband bandwidth. In some examples, UE <NUM>-a may operate according to coverage enhancements that may be provided in different levels (e.g., 5dB, 10dB, or 15dB), which may include bundling of transmissions to provide for coverage enhancement through combining of multiple repeated transmissions.

Some signals transmitted by first base station <NUM>-a and second base station <NUM>-b may be PRS signals that are configured over a wideband PRS bandwidth. Such a wideband PRS bandwidth may cover the entire bandwidth of wideband carriers <NUM>, or may cover a portion of the wideband bandwidth that is still larger than the narrowband regions <NUM> of carriers <NUM>. As indicated above, due to the reduced bandwidth capabilities of UE <NUM>-a, reduced PRS transmission opportunities may be available to the UE <NUM>-a and may present challenges to positioning for the UE <NUM>-a.

In some examples, UE <NUM>-a may determine wideband PRS resources for one or both of base station <NUM>-a or base station <NUM>-b, and may receive portions of the wideband PRS resources that are transmitted in the respective narrowband regions <NUM>, when the narrowband regions <NUM> and in-band with the wideband PRS resources. In examples where the narrowband regions <NUM> are in a standalone frequency band, or in a guard band of wideband carriers <NUM>, the base stations <NUM> may configure dedicated narrowband PRS resources for the narrowband regions <NUM>. In some examples, such dedicated narrowband PRS resources may have a same configuration design as wideband PRS transmission (e.g., two tones per symbol and using established PRS tone hopping).

In other examples, the dedicated narrowband PRS resources may have a different design than established wideband PRS, such as, for example, having one tone per symbol configured for PRS with two tone hopping values, that may provide for a larger frequency reuse for PRS compared to established wideband PRS transmissions. Such larger frequency reuse may provide enhanced frequency diversity for PRS transmissions which may help to enhance PRS measurements. In some examples, one or more other downlink signals, such as a primary synchronization signal (PSS), secondary synchronization signal (SSS), PBCH signal, SIB, or combinations thereof, may be used in conjunction with PRS transmissions to determine positioning measurements that may be used to determine a position of UE <NUM>-a. In some examples, the one or more other downlink signals may be used alone, without associated PRS measurements, to determine UE <NUM>-a position.

In some examples, UE <NUM>-a may transmit signals to first base station <NUM>-a, second base station <NUM>-b, or both, that may be used for position determination of the UE <NUM>-a, either alone or in conjunction with PRS measurements. In such examples, base stations <NUM> may use uplink timing for uplink signals from UE <NUM>-a to determine timing estimations. For example, UE <NUM>-a may transmit physical random access channel (PRACH)-like or physical uplink shared channel (PUSCH)-like transmissions that may be received at base stations <NUM>. The uplink signals, in some examples, may have a signal structure similar to PRACH or PUSCH, but that may be transmitted on a different resources and may be scheduled (different than random PRACH transmissions) or may be random (similar to PRACH transmissions). In some examples where the uplink transmission is scheduled, the time and/or frequency resources used for the uplink transmission may be available to one or more base stations. In such examples, the first base station <NUM>-a and second base station <NUM>-b may coordinate to provide associated timing information for signals received from UE <NUM>-a and determine position of the UE <NUM>-a based at least in part on the timing information. For example, UE <NUM>-a may transmit an initial transmission (e.g., a positioning transmission having similar characteristics to a PRACH transmission) that is aligned to downlink timing of received downlink signals from the first base station <NUM>-a. The initial transmission may be transmitted using a relatively long cyclic prefix. Both the first base station <NUM>-a and second base station <NUM>-b may receive the initial transmission, and perform receive processing on the initial transmission (e.g., PRACH-like processing of the reception, providing an initial timing to within +/- <NUM> microseconds that may not be accurate enough for positioning). First base station <NUM>-a and second base station <NUM>-b may each perform a timing adjustment for the UE <NUM>-a and provide timing adjustment information to the UE <NUM>-a. The UE <NUM>-a, based at least in part on the timing adjustment information, may independently adjust timing for each base station <NUM> and transmit an uplink signal to each base station using a normal cyclic prefix (NCP) or extended cyclic prefix (ECP), either of which have a shorter duration than the cyclic prefix of the initial transmission. Each base station <NUM> may receive the subsequent associated transmission, which would have relatively low residual timing errors, and determine a relatively accurate timing estimation that may be used for positioning determination of the UE <NUM>-a.

<FIG> shows a downlink channel resource block <NUM> in which a PRS <NUM> may be transmitted in a downlink channel, in accordance with various aspects of the present disclosure. By way of example, the downlink channel resource block <NUM> may be transmitted by one of the base stations <NUM> described with reference to <FIG> or <FIG>. By way of an example, the PRS <NUM> shown in <FIG> may be a PRS <NUM> mapped to antenna port <NUM> of the LTE/LTE-A New Carrier Type (NCT). The PRS <NUM> may be transmitted on one or two PBCH antenna ports.

The downlink channel resource block <NUM> includes a plurality of resource elements <NUM>. Each resource element <NUM> may correspond to one of a number of symbol periods (e.g., OFDM symbol positions <NUM>) and one of a number of frequency sub-carriers <NUM>. By way of example, the downlink channel resource block <NUM> includes resource elements spanning fourteen OFDM symbol positions (or two slots, labeled Slot <NUM> and Slot <NUM>; or one Subframe) and twelve frequency sub-carriers. By way of an example, the PRS <NUM> may be transmitted in a set of one or more resource elements <NUM> of the downlink channel resource block <NUM>, such as, in the resource elements labeled R<NUM>. In the example of <FIG>, PRS <NUM> may not be transmitted within the first three symbol <NUM> of the first slot, as the first three symbol <NUM> may be reserved for control channel transmissions.

The PRS <NUM> may have a number of configurable parameters. For example, the PRS <NUM> may have a configuration index, IPRS, mapped to the parameters TPRS and ΔPRS, where TPRS is a periodicity (e.g., <NUM>, <NUM>, <NUM>, or <NUM>) of transmissions of the PRS <NUM>, and where ΔPRS is a subframe offset (e.g., a subframe offset of <NUM> to <NUM>). The PRS <NUM> may additionally or alternatively have configuration parameters such as a duration, NPRS; a number, M, of consecutive transmissions defining a measurement period; muting information (e.g., a muting parameter); a variable cell-specific frequency shift parameter, Vshift; a PRS bandwidth; and a number, n, of cells to measure. The duration, NPRS, may define a number of consecutive downlink subframes included in a PRS transmission (e.g., <NUM>, <NUM>, <NUM>, or <NUM>). The number of consecutive PRS transmissions defining a measurement period may depend on an intra-frequency or inter-frequency configuration of the PRS, and may in some cases be <NUM>, <NUM>, or <NUM>. The muting information may mask PRS transmissions with a periodicity of <NUM>, <NUM>, <NUM>, or <NUM>. The variable cell-specific frequency shift parameter, Vshift, may in some examples be a value between <NUM> and <NUM>, enabling a reuse factor of <NUM>. The PRS bandwidth may in some examples be configured as <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> resource blocks. The number of cells to measure, n, may be any number of cells for which PRS measurements may be made.

A UE such as one of the UEs <NUM> described with reference to <FIG> or <FIG> may receive a PRS such as the PRS <NUM> from one or more base stations <NUM>. The UE may additionally or alternatively receive signaling from the base stations that may indicate configuration parameters for an OTDA reference cell and one or more OTDA neighboring cells. In some examples, an OTDA-ReferenceCell Info message may indicate configuration parameters for the OTDA reference cell, and one or more OTDA-NeighborCell Info messages may indicate configuration parameters for one or more OTDA neighboring cells. The OTDA-NeighborCell Info messages may include a slot timing offset and a PRS subframe offset between the reference cell and neighboring cells. The slot timing offset and the PRS subframe offset may be used for inter-frequency PRS transmissions, where base station transmission timing differences may exceed one subframe. An OTDA-NeighborCell Info message additionally or alternatively enables the use of PRS transmissions in inter-frequency and carrier aggregation mode scenarios.

A UE may make multiple PRS measurements and report an RSTD for n - <NUM> neighboring cells within a measurement period, TRSTD, from the start of an initial PRS transmission. A UE may make a particular number of suitable PRS measurements (e.g., M/<NUM> suitable measurements) within the measurement period, TRSTD, before its PRS measurements are deemed useful.

The PRS transmissions of multiple base stations of a single operator may be synchronized across a same frequency to reduce interference. However, in dense deployments of base stations, a base station may mute its PRS transmission in accordance with a muting pattern.

<FIG> shows a downlink channel resource block <NUM> in which a PRS <NUM> may be transmitted in a downlink channel, in accordance with various aspects of the present disclosure. By way of example, the PRS <NUM> shown in <FIG> may be a PRS <NUM> mapped to antenna port <NUM> of the LTE/LTE-A New Carrier Type (NCT). The PRS <NUM> may be transmitted on four PBCH antenna ports.

The downlink channel resource block <NUM> includes a plurality of resource elements <NUM>. Each resource element <NUM> may correspond to one of a number of symbol periods (e.g., OFDM symbol positions <NUM>) and one of a number of frequency sub-carriers <NUM>. By way of example, the downlink channel resource block <NUM> includes resource elements spanning fourteen OFDM symbol positions (or two slots, labeled Slot <NUM> and Slot <NUM>; or one Subframe) and twelve frequency sub-carriers.

By way of an example, the PRS <NUM> may be transmitted in a set of one or more resource elements <NUM> of the downlink channel resource block <NUM>, such as, in the resource elements labeled R<NUM>. But for the locations of the resource elements <NUM> defining the PRS <NUM>, the downlink channel resource block <NUM> and PRS <NUM> may be configured similarly to the downlink channel resource block <NUM> and PRS <NUM>. In the example of <FIG>, PRS <NUM> may not be transmitted within the first three symbol <NUM> of the first slot, as the first three symbol <NUM> may be reserved for control channel transmissions.

As indicated above, PRS <NUM> and PRS <NUM> may, in some examples, be configured over a PRS bandwidth that may span an entire wideband system bandwidth of a base station, or may be configured to span less than the wideband system bandwidth but still more than a narrowband portion of bandwidth that may be used by narrowband communications devices. In some examples, a base station may configure wideband PRS transmissions (e.g., PRS <NUM>, PRS <NUM>), and a narrowband device may be configured in an in-band deployment and may use the wideband PRS transmissions for PRS measurements. In order to determine PRS measurements, the UE may determine an RB index within the PRS bandwidth, in order to determine for PRS sequencing information, and this RB index might be different from an RB index within the total wideband bandwidth and may additionally or alternatively be different from an RB index within the narrowband bandwidth of the narrowband UE. Thus, in some examples, a UE may identify a RB index within the PRS bandwidth that is different than an RB index of the PRS resources within the narrowband transmission bandwidth and determine the PRS sequence of the PRS transmission based at least in part on the RB index within the PRS bandwidth.

In some examples, a narrowband UE may be capable of receiving a single RB in a particular downlink subframe. In some examples, such bandwidth-limited UEs may oversample the received PRS transmission in order to improve resolution and provide more accurate PRS measurements. In other examples, a narrowband UE may be capable of receiving multiple RBs at its RF front end (e.g., <NUM> RBs) and may be capable of processing a single RB at a time. In such examples, the UE may receive and store multiple RBs simultaneously and store the associated PRS signals. The UE may then serially process narrowband (1RB) baseband signals (e.g., take <NUM> milliseconds to process <NUM> RBs. Such a technique may provide enhanced resolution for PRS measurements without oversampling, thus may have reduced processing requirements at the expense of additional RF front-end and storage capabilities.

In some examples, wideband PRS transmissions, if transmitted in MBSFN subframes, will use ECP, but a narrowband UE may not be capable to support ECP. In such examples, such narrowband UEs may not be able to use PRS subframes that are transmitted in MBSFN subframes, and may skip PRS reception and processing in such subframes. In examples where a narrowband UE may be capable of supporting ECP, a base station may provide additional signaling (e.g., SIB signaling, radio resource control (RRC), or combinations thereof) to enable the UE to identify CP length in wideband PRS subframes.

While the downlink channel resource block <NUM> and downlink channel resource block <NUM> may be used for wideband PRS configuration, in some examples a narrowband UE may not be capable of receiving wideband transmissions or may not be configured to receive in-band narrowband transmissions (e.g., a standalone or guard band deployment). In such cases, a dedicated narrowband PRS may be configured by a base station. Such a dedicated narrowband PRS may be configured with one RB bandwidth, and UEs may use oversampling to improve resolution, in some examples. In some examples, a dedicated narrowband PRS may be configured for transmission to avoid any RBs that include CRS transmissions. In other examples, a base station may configure CRS transmissions to avoid any RBs that include PRS transmissions. Additionally or alternatively, in order to reduce interference, muting may be used, or a frequency of muting may be increased. for PRS configured RBs to assist in the detection of base stations having relatively weak signals. In some examples, different base stations may use different RBs for PRS transmission, to accommodate UEs that are not capable of measuring multiple RBs at the same time. In some examples, in order to provide increased positioning measurement accuracy, the periodicity of the dedicated narrowband PRS may be reduced relative to wideband PRS periodicity. In some examples, the number of consecutive DL subframes with PRS transmission is increased relative to a wideband PRS transmission. For example, additional PRS period values (e.g., <NUM>, <NUM>, <NUM>) may be provided to improve accuracy in deep coverage. Additionally or alternatively, one or more resource elements within the first three symbols of the first slot (e.g., symbols <NUM> of downlink channel resource block <NUM> or symbols <NUM> of downlink channel resource block <NUM>) may be configured for PRS transmission in standalone or guard-band deployment.

In some examples, in order to additionally or alternatively enhance positioning measurements, one or more downlink transmissions other than PRS transmissions may be used for positioning measurements. For example, a UE may use PSS or SSS transmissions to aid in positioning measurements. In some examples, PSS of SSS transmissions may be combined with PRS measurements to enhance measurement accurate by providing a weighted combining of timing estimation of PRS measurements from PRS-based estimation and PSS/SSS-based estimation. For example, a PSS/SSS-based measurement may be more reliable than PRS-based measurements from a particular base station, and then the PSS/SSS-based measurement from that particular base station may be weighted more heavily and combined with PRS measurements that particular base station to reach a final timing estimation. In other examples, a UE may reconstruct the PSS/SSS signals and use PSS or SSS transmissions as pilots in the frequency domain, and may use non-coherent combing with PRS subframes to get a PDP and signal timing estimation. In some examples, measurements from PSS or SSS transmissions may be sufficient to perform accurate positioning determination of the UE, and a dedicated PRS may not be necessary. In some examples, the one or more other downlink transmissions that may aid positioning measurements may be PBCH transmissions, SIB transmissions, or combinations thereof. For example, PBCH/SIB transmissions may be used as pilots to improve positioning, through non-coherent combing with PRS subframes to get PDP. In some examples, measurements from PBCH or SIB transmissions may be sufficient to perform accurate positioning determination of the UE, and a dedicated PRS may not be necessary.

<FIG> illustrates an example of a wideband and narrowband resources <NUM> for positioning signals for narrowband devices. In some cases, wideband and narrowband resources <NUM> may represent aspects of techniques performed by a UE <NUM> or base station <NUM> as described with reference to <FIG>. In the example of <FIG>, a system bandwidth <NUM> may be available at a base station for wideband transmissions, and the base station may configure a wideband PRS bandwidth <NUM> to span the entire system bandwidth <NUM>. Narrowband RBs <NUM>, may be configured in a narrowband portion of the system bandwidth <NUM>, and may be used for narrowband communications with one or more narrowband UEs.

In the example, of <FIG>, a UE may be capable of receiving both wideband PRS transmissions, as well as narrowband PRS transmissions, and in some subframes may measure wideband PRS, and measure narrowband PRS transmissions in some subframes.

In some cases, a wideband PRS bandwidth may be less than a system bandwidth, and a base station may use one or more portions of the system bandwidth for special narrowband PRS transmissions in order to enhance PRS measurements at a UE. <FIG> illustrates an example of a wideband and narrowband resources <NUM> for positioning signals for narrowband devices. In some cases, wideband and narrowband resources <NUM> may represent aspects of techniques performed by a UE <NUM> or base station <NUM> as described with reference to <FIG>. In the example of <FIG>, a system bandwidth <NUM> may be available at a base station for wideband transmissions, and the base station may configure a wideband PRS bandwidth <NUM> to span less than the entire system bandwidth <NUM>. Special PRS RBs for narrowband <NUM>-a, <NUM>-b, and <NUM>-c may be configured in narrowband portions of the system bandwidth <NUM> that are non-overlapping with wideband PRS bandwidth <NUM>. A base station may configure, in some examples, the special PRS RBs for narrowband <NUM> to provide additional PRS transmissions to narrowband UEs. In some examples, the special PRS RBs for narrowband <NUM> are not used for other narrowband channels.

<FIG> illustrates an example of wireless resources <NUM> for dedicated narrowband PRS transmissions according to some aspects of the present disclosure. In some cases, wireless resources <NUM> may represent aspects of techniques performed by a UE <NUM> or base station <NUM> as described with reference to <FIG>. Wireless resources <NUM> may include resources configured for PRS <NUM> may be transmitted in a downlink channel, in accordance with various aspects of the present disclosure.

The wireless resources <NUM> includes a plurality of resource elements <NUM>. Each resource element <NUM> may correspond to one of a number of symbol periods (e.g., OFDM symbol positions <NUM>) and one of a number of frequency sub-carriers <NUM>. By way of example, the wireless resources <NUM> includes resource elements spanning fourteen OFDM symbol positions (or two slots, labeled Slot <NUM> and Slot <NUM>; or one Subframe) and twelve frequency sub-carriers.

In the example of <FIG>, the PRS <NUM> may be transmitted in a set of one or more resource elements <NUM> of the wireless resources <NUM>, such as, in the resource elements labeled R<NUM>. In this example, a single tone per symbol <NUM> may be used for PRS <NUM> (thus providing a design similar to a PRACH design used for uplink PRACH transmissions). The PRS <NUM> may be configured with multiple hopping values, such as a first tone hopping value <NUM> that identifies a hopping value to be used in some symbols <NUM>, and a second tone hopping value <NUM> that may be used in some symbols <NUM>. By providing multiple hopping values, increased frequency reuse (e.g., frequency reuse of <NUM>) may be provided relative to frequency reuse that may be available if two PRS tones per symbol <NUM> were to be used. In some examples, first tone hopping value <NUM> provides tone hopping of one tone, and second tone hopping value <NUM> provides tone hopping of six tones. In some examples, additional tone hopping values may be used, in which case the configured PRS <NUM> REs may converge to current PRS-like design (e.g., as discussed in <FIG>) as the number of hopping values increases.

<FIG> illustrates an example of a process flow <NUM> for positioning signals for narrowband devices in accordance with various aspects of the present disclosure. Process flow <NUM> may include first base station <NUM>-c, second base station <NUM>-b, and UE <NUM>-b, which may be examples of the corresponding devices described with reference to <FIG>.

UE <NUM>-b may be a narrowband UE, similarly as discussed above, that may be capable of transmitting and receiving narrowband transmissions within a wideband system bandwidth or in a guard band or standalone deployment. First base station <NUM>-c may communicate channel configuration information <NUM> with UE <NUM>-b, and second base station <NUM>-d may communicate channel configuration information <NUM> with UE <NUM>-b. Based at least in part on the channel configuration information, UE <NUM>-b may identify PRS resources, as indicated at block <NUM>. The first base station <NUM>-c may generate a first PRS as indicated at block <NUM> and transmit the first PRS in transmission <NUM>. The first PRS may be transmitted, in some examples, in-band with a wideband transmission <NUM> of the first base station <NUM>-c, although guard band or standalone transmissions may be used in some examples. The second base station <NUM>-d may generate a second PRS as indicated at block <NUM> and transmit the second PRS in transmission <NUM>. The second PRS may be transmitted, in some examples, in-band with a wideband transmission of the first base station <NUM>-c, although guard band or standalone transmissions may be used in some examples. The UE <NUM>-b, at block <NUM>, may sample and process received signals, in a manner similarly as discussed above with respect to <FIG>. At block <NUM>, the UE may determine positioning parameters, such as timing or signal parameters as discussed above that may be used for position determination. The UE <NUM>-b may optionally transmit the positioning parameters <NUM> to first base station <NUM>-c (or another entity), which may at block <NUM> estimate a position of the UE <NUM>-b. In some examples, UE <NUM>-b may estimate its own position based at least in part on the positioning parameters, as indicated at block <NUM>.

<FIG> shows a block diagram of a wireless device <NUM> that supports positioning signals for narrowband devices in accordance with various aspects of the present disclosure. Wireless device <NUM> may be an example of aspects of a UE <NUM> described with reference to <FIG>. Wireless device <NUM> may include receiver <NUM>, positioning signal manager <NUM> and transmitter <NUM>. Wireless device <NUM> may additionally or alternatively include a processor. Each of these components may be in communication with each other.

The receiver <NUM> may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to positioning signals for narrowband devices, etc.). Information may be passed on to other components of the device. The receiver <NUM> may be an example of aspects of the transceiver <NUM> described with reference to <FIG>.

The positioning signal manager <NUM> may identify PRS resources, and receive, on the PRS resources within a narrowband transmission bandwidth, one or more PRS transmissions in at least one DL subframe among a set of DL subframes. The PRS resources may be PRS resources within a wideband PRS transmission, or may be dedicated PRS resources for narrowband devices. The positioning signal manager <NUM> may, in some examples, identify a plurality of symbols of a DL subframe for PRS reception, identify a single tone configured as a PRS tone within two or more symbols of the plurality of symbols based at least in part on a symbol location of each symbol and a tone hopping value, and receive, on the identified PRS tones, one or more PRS transmissions.

In some examples, the positioning signal manager <NUM> may manage position determination based at least in part on one or more uplink signals from wireless device <NUM>. In such examples, the positioning signal manager <NUM> may receive one or more DL transmissions from a first base station, determine a first DL timing for the first base station, transmit a first UL transmission aligned to the first DL timing and including a first CP having a first CP duration, receive a timing adjustment from the first base station, and transmit a second UL transmission to the first base station, the second UL transmission based at least in part on the timing adjustment and including a second CP having a second CP duration that is less than the first CP duration. The positioning signal manager <NUM> may be an example of aspects of the positioning signal manager <NUM> described with reference to <FIG>.

The transmitter <NUM> may transmit signals received from other components of wireless device <NUM>. In some examples, the transmitter <NUM> may be collocated with a receiver in a transceiver module. The transmitter <NUM> may include a single antenna, or it may include a plurality of antennas.

<FIG> shows a block diagram of a wireless device <NUM> that supports positioning signals for narrowband devices in accordance with various aspects of the present disclosure. Wireless device <NUM> may be an example of aspects of a wireless device <NUM> or a UE <NUM> described with reference to <FIG>. Wireless device <NUM> may include receiver <NUM>, positioning signal manager <NUM> and transmitter <NUM>. Wireless device <NUM> may additionally or alternatively include a processor. Each of these components may be in communication with each other.

The receiver <NUM> may receive information which may be passed on to other components of the device. The receiver <NUM> may additionally or alternatively perform the functions described with reference to the receiver <NUM> of <FIG>. The receiver <NUM> may be an example of aspects of the transceiver <NUM> described with reference to <FIG>.

The positioning signal manager <NUM> may be an example of aspects of positioning signal manager <NUM> described with reference to <FIG>. The positioning signal manager <NUM> may include narrowband (NB) resource component <NUM>, NB PRS component <NUM>, tone hopping component <NUM> and timing alignment component <NUM>. The positioning signal manager <NUM> may be an example of aspects of the positioning signal manager <NUM> described with reference to <FIG>.

The NB resource component <NUM> may identify a PRS bandwidth and PRS resources in one or more DL subframe of a set of DL subframes. In some cases, the PRS bandwidth is greater than the narrowband transmission bandwidth and less than or equal to a wideband system bandwidth of a transmitter that transmits the one or more PRS transmissions. In some cases, the PRS resources within a narrowband transmission bandwidth include resources within a single RB of the narrowband transmission bandwidth. In some cases, the PRS resources include wireless transmission resources in a standalone narrowband transmission bandwidth that is outside of a wideband system bandwidth of one or more transmitters of the PRS transmissions, or wireless transmission resources in a guard band bandwidth that is adjacent to the wideband system bandwidth of one or more transmitters of the PRS transmissions.

In some cases, the single RB of the narrowband transmission bandwidth does not include one or more of a CRS or PRS transmissions from multiple transmitters. In some cases, a periodicity of PRS transmissions within the narrowband transmission bandwidth is reduced relative to a wideband PRS transmission periodicity. In some cases, the number of consecutive DL subframes with PRS transmission is increased relative to a wideband PRS transmission periodicity. In some cases, the PRS resources within the single RB include PRS resources within one or more of a first through third symbol of the single RB.

In some cases, NB resource component <NUM> may identify a first PRS bandwidth in a first DL subframe of the set of DL subframes as being within a wideband system bandwidth of one or more transmitters that transmit the PRS transmissions. In some cases, a PRS bandwidth of the one or more PRS transmissions is different than the narrowband transmission bandwidth, and the identifying includes identifying a RB index within the PRS bandwidth that is different than an RB index of the PRS resources within the narrowband transmission bandwidth.

The NB PRS component <NUM> may receive, on the PRS resources within the narrowband transmission bandwidth, one or more PRS transmissions in at least one DL subframe among a set of DL subframes. In some cases, the receiving includes receiving a set of RBs in a set of narrowband transmission bandwidths in the at least one DL subframe.

The tone hopping component <NUM> may identify a set of symbols of a DL subframe for PRS reception, identify a single tone configured as a PRS tone within each of two or more symbols of the set of symbols based at least in part on a symbol location of each symbol and a tone hopping value, receive, on the identified PRS tones, one or more PRS transmissions, identify a second PRS tone location for a second symbol based at least in part on the first tone hopping value and a first PRS tone location of the first symbol, identify a second tone hopping value for the second symbol, and identify a third PRS tone location for a third symbol based at least in part on the second tone hopping value and the second PRS tone location.

In some cases, the identifying the single tone within each of the two or more symbols includes identifying a first tone hopping value for a first symbol. In some cases, the tone hopping value identifies different tones within consecutive symbols configured as PRS tones.

The timing alignment component <NUM> may receive one or more DL transmissions from a first base station, determine a first DL timing for the first base station, transmit a first UL transmission aligned to the first DL timing and including a first CP having a first CP duration, receive a timing adjustment from the first base station, and transmit a second UL transmission to the first base station, the second UL transmission based at least in part on the timing adjustment and including a second CP having a second CP duration that is less than the first CP duration.

The transmitter <NUM> may transmit signals received from other components of wireless device <NUM>. In some examples, the transmitter <NUM> may be collocated with a receiver in a transceiver module. The transmitter <NUM> may utilize a single antenna, or it may utilize a plurality of antennas.

<FIG> shows a block diagram of a positioning signal manager <NUM> which may be an example of the corresponding component of wireless device <NUM> or wireless device <NUM>. That is, positioning signal manager <NUM> may be an example of aspects of positioning signal manager <NUM> or positioning signal manager <NUM> described with reference to <FIG> and <FIG>. The positioning signal manager <NUM> may additionally or alternatively be an example of aspects of the positioning signal manager <NUM> described with reference to <FIG>.

The positioning signal manager <NUM> may include sampling component <NUM>, serial processing component <NUM>, CP length component <NUM>, control channel component <NUM>, tone hopping component <NUM>, timing alignment component <NUM>, NB resource component <NUM>, PRS sequence component <NUM> and NB PRS component <NUM>. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The sampling component <NUM> may sample signals received in the PRS resources at a higher sampling rate than sampling of other signals received in the set of DL subframes. The serial processing component <NUM> may serially process two or more RBs received at a RF front end to determine one or more positioning parameters associated with the one or more PRS transmissions. In some cases, the one or more positioning parameters include one or more of an RSTD measurement between PRS transmissions of two or more transmitters, an RSSI of one or more of the PRS transmissions, or an OTDA between PRS transmissions of two or more transmitters.

The CP length component <NUM> may in some cases, identify a CP length of the one or more PRS transmissions based at least in part on a type of subframe of the at least one DL subframe. In some cases, the CP length is identified as an extended CP length when the type of subframe is a Multimedia Broadcast Single Frequency Network (MBSFN) subframe.

The downlink channel component <NUM> may identify wireless transmission resources within the narrowband transmission bandwidth for one or more downlink channels, receive, on the one or more downlink channels, one or more downlink signals from one or more transmitters, and process the one or more downlink signals to determine one or more positioning parameters in addition to one or more PRS-based positioning parameters. In some cases, the one or more downlink signals includes one or more of a PSS, a SSS, a PBCH signal, or a SIB signal. In some cases, the processing includes non-coherent combining of the one or more downlink signals with one or more PRS transmissions to determine a PDP. In some cases, the processing includes weighted combining of two or more PRS-based positioning parameters based at least in part on measurements associated with the one or more downlink signals.

The NB resource component <NUM> may identify PRS bandwidths and PRS resources in DL subframes, and identify PRS resources within a wideband or narrowband transmission bandwidth. The PRS sequence component <NUM> may determine a PRS sequence based at least in part on the RB index within the PRS bandwidth.

<FIG> shows a diagram of a system <NUM> including a device that supports positioning signals for narrowband devices in accordance with various aspects of the present disclosure. For example, system <NUM> may include UE <NUM>-c, which may be an example of a wireless device <NUM>, a wireless device <NUM>, or a UE <NUM> as described with reference to <FIG>.

UE <NUM>-c may additionally or alternatively include positioning signal manager <NUM>, memory <NUM>, processor <NUM>, transceiver <NUM>, antenna <NUM> and MTC module <NUM>. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses). The positioning signal manager <NUM> may be an example of a positioning signal manager as described with reference to <FIG>.

The memory <NUM> may include random access memory (RAM) and read only memory (ROM). The memory <NUM> may store computer-readable, computer-executable software including instructions that, when executed, cause the processor to perform various functions described herein (e.g., positioning signals for narrowband devices, etc.). In some cases, the software <NUM> may not be directly executable by the processor but may cause a computer (e.g., when compiled and executed) to perform functions described herein. The processor <NUM> may include an intelligent hardware device, (e.g., a central processing unit (CPU), a microcontroller, an application specific integrated circuit (ASIC), etc.).

The transceiver <NUM> may communicate bi-directionally, via one or more antennas, wired, or wireless links, with one or more networks, as described above. For example, the transceiver <NUM> may communicate bi-directionally with a base station <NUM> or a UE <NUM>. The transceiver <NUM> may additionally or alternatively include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

MTC module <NUM> may enable MTC or internet-of-things (IoT) operations as described above with reference to <FIG>, including narrowband operations.

<FIG> shows a block diagram of a wireless device <NUM> that supports positioning signals for narrowband devices in accordance with various aspects of the present disclosure. Wireless device <NUM> may be an example of aspects of a base station <NUM> described with reference to <FIG>. Wireless device <NUM> may include receiver <NUM>, base station positioning signal manager <NUM> and transmitter <NUM>. Wireless device <NUM> may additionally or alternatively include a processor. Each of these components may be in communication with each other.

The base station positioning signal manager <NUM> may identify PRS resources within a wideband or narrowband transmission bandwidth, generate a PRS based at least in part on the identified PRS resources, and transmit, on the PRS resources within the wideband or narrowband transmission bandwidth, the PRS in at least one DL subframe among a set of DL subframes.

The base station positioning signal manager <NUM> may additionally or alternatively, in some examples, configure a set of symbols of a DL subframe for PRS transmission, configure, within each of the set of symbols, a single tone as a PRS tone within each symbol based at least in part on a symbol location of each symbol and a tone hopping value, and transmit the PRS on the configured tones of the set of symbols.

The base station positioning signal manager <NUM> may additionally or alternatively, in some examples, receive a first UL transmission from a UE, the first UL transmission aligned to DL timing of the UE and including a first CP having a first CP duration, transmit to the UE a timing adjustment for a second UL transmission by the UE, receive the second UL transmission from the UE, the second UL transmission based at least in part on the timing adjustment and including a second CP having a second CP duration that is less than the first CP duration, and determine an RTD for transmissions with the UE based at least in part on a time of receipt of the second UL transmission. The base station positioning signal manager <NUM> may be an example of aspects of the base station positioning signal manager <NUM> described with reference to <FIG>.

<FIG> shows a block diagram of a wireless device <NUM> that supports positioning signals for narrowband devices in accordance with various aspects of the present disclosure. Wireless device <NUM> may be an example of aspects of a wireless device <NUM> or a base station <NUM> described with reference to <FIG>, and <FIG>. Wireless device <NUM> may include receiver <NUM>, base station positioning signal manager <NUM> and transmitter <NUM>. Wireless device <NUM> may additionally or alternatively include a processor. Each of these components may be in communication with each other.

The base station positioning signal manager <NUM> may be an example of aspects of base station positioning signal manager <NUM> described with reference to <FIG>. The base station positioning signal manager <NUM> may include NB resource component <NUM>, PRS component <NUM>, tone hopping component <NUM>, timing alignment component <NUM> and RTD component <NUM>. The base station positioning signal manager <NUM> may be an example of aspects of the base station positioning signal manager <NUM> described with reference to <FIG>.

The NB resource component <NUM> may identify PRS resources within a narrowband transmission bandwidth. In some cases, the narrowband transmission bandwidth is a subset of a wideband transmission bandwidth. In some cases, the PRS resources within the narrowband transmission bandwidth include resources within a single RB of the narrowband transmission bandwidth. In some cases, the PRS resources include wireless transmission resources in a standalone narrowband transmission bandwidth that is outside of a wideband system bandwidth, or wireless transmission resources in a guard band bandwidth that is adjacent to the wideband system bandwidth.

In some cases, the single RB of the narrowband transmission bandwidth does not include a CRS. In some cases, a periodicity of PRS transmissions within the narrowband transmission bandwidth is reduced relative to a wideband PRS transmission periodicity. In some cases, the number of consecutive DL subframes with PRS transmission is increased relative to a wideband PRS transmission.

The PRS component <NUM> may generate a PRS based at least in part on the identified PRS resources, and transmit, on the PRS resources within the narrowband transmission bandwidth, the PRS in at least one DL subframe among a set of DL subframes.

The tone hopping component <NUM> may configure a set of symbols of a DL subframe for PRS transmission, configure, within each of the set of symbols, a single tone as a PRS tone within each symbol based at least in part on a symbol location of each symbol and a tone hopping value, transmit the PRS on the configured tones of the set of symbols, configure a second PRS tone location for a second symbol based at least in part on the first tone hopping value and a first PRS tone location of the first symbol, configure a second tone hopping value for the second symbol, and configure a third PRS tone location for a third symbol based at least in part on the second tone hopping value and the second PRS tone location. In some cases, the configuring the single tone within each symbol includes configuring a first tone hopping value for a first symbol. In some cases, the tone hopping value identifies different tones within consecutive symbols configured as PRS tones.

The timing alignment component <NUM> may receive a first UL transmission from a UE, the first UL transmission aligned to DL timing of the UE and including a first CP having a first CP duration, transmit to the UE a timing adjustment for a second UL transmission by the UE, and receive the second UL transmission from the UE, the second UL transmission based at least in part on the timing adjustment and including a second CP having a second CP duration that is less than the first CP duration.

The RTD component <NUM> may determine an RTD for transmissions with the UE based at least in part on a time of receipt of the second UL transmission, and receive a set of RTDs associated with the UE from two or more other base stations.

<FIG> shows a block diagram of a base station positioning signal manager <NUM> which may be an example of the corresponding component of wireless device <NUM> or wireless device <NUM>. That is, base station positioning signal manager <NUM> may be an example of aspects of base station positioning signal manager <NUM> or base station positioning signal manager <NUM> described with reference to <FIG> and <FIG>. The base station positioning signal manager <NUM> may additionally or alternatively be an example of aspects of the base station positioning signal manager <NUM> described with reference to <FIG>.

The base station positioning signal manager <NUM> may include base station coordinating component <NUM>, PRS measurement component <NUM>, position estimation component <NUM>, tone hopping component <NUM>, timing alignment component <NUM>, RTD component <NUM>, position determining component <NUM>, NB resource component <NUM> and PRS component <NUM>. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses).

The base station coordinating component <NUM> may coordinate with one or more base stations to mute transmissions of the one or more other base stations during the transmission of the single RB.

The PRS measurement component <NUM> may receive a first measurement associated with the PRS from a UE, and receive a second measurement associated with one or more other downlink channel signals received at the UE. In some cases, the one or more other downlink channel signals includes one or more of a PSS, a SSS, a PBCH signal, or a SIB signal. In some cases, the second measurement includes a PDP based at least in part on a non-coherent combining of the one or more other downlink channel signals with the PRS transmission. In some cases, the second measurement may include a weighting factor to be applied when combining PRS measurements. The position estimation component <NUM> may estimate a position of the UE based at least in part on the first measurement and the second measurement.

The tone hopping component <NUM> may configure a set of symbols of a DL subframe for PRS transmission, configure, within each of the set of symbols, a single tone as a PRS tone within each symbol based at least in part on a symbol location of each symbol and a tone hopping value, transmit the PRS on the configured tones of the set of symbols, configure a second PRS tone location for a second symbol based at least in part on the first tone hopping value and a first PRS tone location of the first symbol, configure a second tone hopping value for the second symbol, and configure a third PRS tone location for a third symbol based at least in part on the second tone hopping value and the second PRS tone location.

The RTD component <NUM> may determine an RTD for transmissions with the UE based at least in part on a time of receipt of the second UL transmission, and receive a set of RTDs associated with the UE from two or more other base stations. The position determining component <NUM> may determine a position of the UE based at least in part on the set of RTDs and a known position of the two or more other base stations, and receive one or more PRS-based measurements from the UE, and wherein the determining the position of the UE is additionally or alternatively based at least in part on the PRS-based measurements.

The NB resource component <NUM> may PRS resources within a narrowband transmission bandwidth. The PRS component <NUM> may generate a PRS based at least in part on the identified PRS resources, and transmit, on the PRS resources within the narrowband transmission bandwidth, the PRS in at least one DL subframe among a set of DL subframes.

<FIG> shows a diagram of a wireless system <NUM> including a device configured that supports positioning signals for narrowband devices in accordance with various aspects of the present disclosure. For example, system <NUM> may include base station <NUM>-f, which may be an example of a wireless device <NUM>, a wireless device <NUM>, or a base station <NUM> as described with reference to <FIG>, and <FIG>. Base station <NUM>-f may additionally or alternatively include components for bi-directional voice and data communications including components for transmitting communications and components for receiving communications. For example, base station <NUM>-f may communicate bi-directionally with one or more UEs <NUM>.

Base station <NUM>-f may additionally or alternatively include base station positioning signal manager <NUM>, memory <NUM>, processor <NUM>, transceiver <NUM>, antenna <NUM>, base station communications module <NUM> and network communications module <NUM>. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses). The base station positioning signal manager <NUM> may be an example of a base station positioning signal manager as described with reference to <FIG>.

The memory <NUM> may include RAM and ROM. The memory <NUM> may store computer-readable, computer-executable software including instructions that, when executed, cause the processor to perform various functions described herein (e.g., positioning signals for narrowband devices, etc.). In some cases, the software <NUM> may not be directly executable by the processor but may cause a computer (e.g., when compiled and executed) to perform functions described herein. The processor <NUM> may include an intelligent hardware device, (e.g., a CPU, a microcontroller, an ASIC, etc.).

The transceiver <NUM> may communicate bi-directionally, via one or more antennas, wired, or wireless links, with one or more networks, as described above. For example, the transceiver <NUM> may communicate bi-directionally with a base station <NUM> or a UE <NUM>. The transceiver <NUM> may additionally or alternatively include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

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

The network communications module <NUM> may manage communications with the core network (e.g., via one or more wired backhaul links). For example, the network communications module <NUM> may manage the transfer of data communications for client devices, such as one or more UEs <NUM>.

<FIG> shows a flowchart illustrating a method <NUM> for positioning signals for narrowband devices in accordance with various aspects of the present disclosure. The operations of method <NUM> may be implemented by a device such as a UE <NUM> or its components as described with reference to <FIG>. For example, the operations of method <NUM> may be performed by the positioning signal manager as described herein. In some examples, the UE <NUM> may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the UE <NUM> may perform aspects the functions described below using special-purpose hardware.

At block <NUM>, the UE <NUM> may identify PRS resources within a transmission bandwidth as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the NB resource component as described with reference to <FIG> and <FIG>.

At block <NUM>, the UE <NUM> may receive, on the PRS resources within a narrowband transmission bandwidth, one or more PRS transmissions in at least one DL subframe among a set of DL subframes as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the NB PRS component as described with reference to <FIG> and <FIG>.

At block <NUM>, the UE <NUM> may identify PRS resources as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the NB resource component as described with reference to <FIG> and <FIG>.

At block <NUM>, the UE <NUM> may identify wireless transmission resources within the narrowband transmission bandwidth for one or more downlink channels as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the downlink channel component as described with reference to <FIG> and <FIG>.

At block <NUM>, the UE <NUM> may receive, on the one or more downlink channels, one or more downlink signals from one or more transmitters as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the downlink channel component as described with reference to <FIG> and <FIG>.

At block <NUM>, the UE <NUM> may process the one or more downlink signals to determine one or more positioning parameters in addition to one or more PRS-based positioning parameters as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the downlink channel component as described with reference to <FIG> and <FIG>.

<FIG> shows a flowchart illustrating a method <NUM> for positioning signals for narrowband devices in accordance with various aspects of the present disclosure. The operations of method <NUM> may be implemented by a device such as a base station <NUM> or its components as described with reference to <FIG> and <FIG>. For example, the operations of method <NUM> may be performed by the base station positioning signal manager as described herein. In some examples, the base station <NUM> may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the base station <NUM> may perform aspects the functions described below using special-purpose hardware.

At block <NUM>, the base station <NUM> may PRS resources within a wideband or narrowband transmission bandwidth as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the NB resource component as described with reference to <FIG> and <FIG>.

At block <NUM>, the base station <NUM> may generate a PRS based at least in part on the identified PRS resources as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the PRS component as described with reference to <FIG> and <FIG>.

At block <NUM>, the base station <NUM> may transmit, on the PRS resources within the wideband or narrowband transmission bandwidth, the PRS in at least one DL subframe among a set of DL subframes as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the PRS component as described with reference to <FIG> and <FIG>.

<FIG> shows a flowchart illustrating a method <NUM> for positioning signals for narrowband devices in accordance with various aspects of the present disclosure. The operations of method <NUM> may be implemented by a device such as a base station <NUM> or its components as described with reference to <FIG>. For example, the operations of method <NUM> may be performed by the base station positioning signal manager as described herein. In some examples, the base station <NUM> may execute a set of codes to control the functional elements of the device to perform the functions described below. Additionally or alternatively, the base station <NUM> may perform aspects the functions described below using special-purpose hardware.

At block <NUM>, the base station <NUM> may identify PRS resources within a narrowband transmission bandwidth as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the NB resource component as described with reference to <FIG> and <FIG>.

At block <NUM>, the base station <NUM> may transmit, on the PRS resources within the narrowband transmission bandwidth, the PRS in at least one DL subframe among a set of DL subframes as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the PRS component as described with reference to <FIG> and <FIG>.

At block <NUM>, the base station <NUM> may receive a first measurement associated with the PRS from a UE as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the PRS measurement component as described with reference to <FIG> and <FIG>.

At block <NUM>, the base station <NUM> may receive a second measurement associated with one or more other downlink channel signals received at the UE as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the PRS measurement component as described with reference to <FIG> and <FIG>.

At block <NUM>, the base station <NUM> may estimate a position of the UE based at least in part on the first measurement and the second measurement as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the position estimation component as described with reference to <FIG> and <FIG>.

At block <NUM>, the UE <NUM> may identify a set of symbols of a DL subframe for PRS reception as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the tone hopping component as described with reference to <FIG> and <FIG>.

At block <NUM>, the UE <NUM> may identify a single tone configured as a PRS tone within each of two or more symbols of the set of symbols based at least in part on a symbol location of each symbol and a tone hopping value as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the tone hopping component as described with reference to <FIG> and <FIG>.

At block <NUM>, the UE <NUM> may receive, on the identified PRS tones, one or more PRS transmissions as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the tone hopping component as described with reference to <FIG> and <FIG>.

At block <NUM>, the base station <NUM> may configure a set of symbols of a DL subframe for PRS transmission as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the tone hopping component as described with reference to <FIG> and <FIG>.

At block <NUM>, the base station <NUM> may configure, within each of the set of symbols, a single tone as a PRS tone within each symbol based at least in part on a symbol location of each symbol and a tone hopping value as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the tone hopping component as described with reference to <FIG> and <FIG>.

At block <NUM>, the base station <NUM> may transmit the PRS on the configured tones of the set of symbols as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the tone hopping component as described with reference to <FIG> and <FIG>.

At block <NUM>, the UE <NUM> may receive one or more DL transmissions from a first base station as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the timing alignment component as described with reference to <FIG> and <FIG>.

At block <NUM>, the UE <NUM> may determine a first DL timing for the first base station as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the timing alignment component as described with reference to <FIG> and <FIG>.

At block <NUM>, the UE <NUM> may transmit a first UL transmission aligned to the first DL timing and including a first CP having a first CP duration as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the timing alignment component as described with reference to <FIG> and <FIG>.

At block <NUM>, the UE <NUM> may receive a timing adjustment from the first base station as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the timing alignment component as described with reference to <FIG> and <FIG>.

At block <NUM>, the UE <NUM> may transmit a second UL transmission to the first base station, the second UL transmission based at least in part on the timing adjustment and including a second CP having a second CP duration that is less than the first CP duration as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the timing alignment component as described with reference to <FIG> and <FIG>.

At block <NUM>, the base station <NUM> may receive a first UL transmission from a UE, the first UL transmission aligned to DL timing of the UE and including a first CP having a first CP duration as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the timing alignment component as described with reference to <FIG> and <FIG>.

At block <NUM>, the base station <NUM> may transmit to the UE a timing adjustment for a second UL transmission by the UE as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the timing alignment component as described with reference to <FIG> and <FIG>.

At block <NUM>, the base station <NUM> may receive the second UL transmission from the UE, the second UL transmission based at least in part on the timing adjustment and including a second CP having a second CP duration that is less than the first CP duration as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the timing alignment component as described with reference to <FIG> and <FIG>.

At block <NUM>, the base station <NUM> may determine an RTD for transmissions with the UE based at least in part on a time of receipt of the second UL transmission as described above with reference to <FIG>. In some examples, the operations of block <NUM> may be performed by the RTD component as described with reference to <FIG> and <FIG>.

In some examples, aspects from two or more of the methods <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> may be combined as described with reference to <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, or <FIG>. It should be noted that the methods <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are just example implementations, and that the operations of the methods <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM> may be rearranged or otherwise modified such that other implementations are possible. For example, aspects of each of the methods may include steps or aspects of the other methods, or other steps or techniques described herein. Thus, aspects of the disclosure may provide for positioning signals for narrowband devices.

The description herein is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not to be limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the appended claims.

Other examples and implementations are within the scope of the appended claims. Also, as used herein, including in the claims, "or" as used in a list of items (for example, a list of items prefaced by a phrase such as "at least one of" or "one or more of") indicates a disjunctive list such that, for example, a list of "at least one of A, B, or C" means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

By way of example, and not limitation, non-transitory computer-readable media can include RAM, ROM, electrically erasable programmable read only memory (EEPROM), compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Additionally or alternatively, any connection is properly termed a computer-readable medium. Combinations of the above are additionally or alternatively included within the scope of computer-readable media.

Techniques described herein may be used for various wireless communications systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms "system" and "network" are often used interchangeably. IS-<NUM> Releases <NUM> and A are commonly referred to as CDMA2000 1X, 1X, etc. IS-<NUM> (TIA-<NUM>) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement a radio technology such as (Global System for Mobile communications (GSM)). An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE <NUM>, IEEE <NUM> (WiMAX), IEEE <NUM>, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications system (Universal Mobile Telecommunications System (UMTS)). 3GPP LTE and LTE-advanced (LTE-A) are new releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-a, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). The description herein, however, describes an LTE system for purposes of example, and LTE terminology is used in much of the description above, although the techniques are applicable beyond LTE applications.

In LTE/LTE-A networks, including networks described herein, the term evolved node B (eNB) may be used to describe the base stations. The wireless communications system or systems described herein may include a heterogeneous LTE/LTE-A network in which different types of eNBs provide coverage for various geographical regions. For example, each eNB or base station may provide communication coverage for a macro cell, a small cell, or other types of cell. The term "cell" is a 3GPP term that can be used to describe a base station, a carrier or component carrier (CC) associated with a base station, or a coverage area (e.g., sector, etc.) of a carrier or base station, depending on context.

Base stations may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point (AP), a radio transceiver, a NodeB, eNodeB (eNB), Home NodeB, a Home eNodeB, or some other suitable terminology. The geographic coverage area for a base station may be divided into sectors making up a portion of the coverage area. The wireless communications system or systems described herein may include base stations of different types (e.g., macro or small cell base stations). The UEs described herein may be able to communicate with various types of base stations and network equipment including macro eNBs, small cell eNBs, relay base stations, and the like. There may be overlapping geographic coverage areas for different technologies. In some cases, different coverage areas may be associated with different communication technologies. In some cases, the coverage area for one communication technology may overlap with the coverage area associated with another technology. Different technologies may be associated with the same base station, or with different base stations.

A macro cell covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell is a lower-powered base stations, as compared with a macro cell, that may operate in the same or different (e.g., licensed, unlicensed, etc.) frequency bands as macro cells. A femto cell may additionally or alternatively cover a small geographic area (e.g., a home) and may provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG), UEs for users in the home, and the like). An eNB may support one or multiple (e.g., two, three, four, and the like) cells (e.g., component carriers (CCs)). A UE may be able to communicate with various types of base stations and network equipment including macro eNBs, small cell eNBs, relay base stations, and the like.

The DL transmissions described herein may additionally or alternatively be called forward link transmissions while the UL transmissions may additionally or alternatively be called reverse link transmissions. Each communication link described herein including, for example, wireless communications system <NUM> and <NUM> of <FIG> and <FIG> may include one or more carriers, where each carrier may be a signal made up of multiple sub-carriers (e.g., waveform signals of different frequencies). Each modulated signal may be sent on a different sub-carrier and may carry control information (e.g., reference signals, control channels, etc.), overhead information, user data, etc. The communication links described herein (e.g., communication links <NUM> of <FIG>) may transmit bidirectional communications using frequency division duplex (FDD) (e.g., using paired spectrum resources) or time division duplex (TDD) operation (e.g., using unpaired spectrum resources). Frame structures may be defined for FDD (e.g., frame structure type <NUM>) and TDD (e.g., frame structure type <NUM>).

Thus, aspects of the disclosure may provide for positioning signals for narrowband devices. It should be noted that these methods describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified such that other implementations are possible. In some examples, aspects from two or more of the methods may be combined.

Claim 1:
A method for wireless communication at a narrowband communications device, comprising:
identifying (<NUM>, <NUM>, <NUM>) positioning reference signal, PRS, resources within a standalone narrowband transmission bandwidth that is outside of a wideband system bandwidth or in a guard band bandwidth that is adjacent to the wideband system bandwidth; and
receiving (<NUM>, <NUM>), on the PRS resources within the standalone narrowband transmission bandwidth or the guard band bandwidth, one or more PRS transmissions (<NUM>, <NUM>) in at least one downlink subframe among a plurality of downlink subframes, wherein the PRS resources within the narrowband transmission bandwidth comprise resources within a single resource block, RB, of the narrowband transmission bandwidth, wherein the PRS resources within the single RB comprising PRS resources within each of a first through third symbol of the single RB, and wherein the one or more PRS transmissions are received in the single RB from a base station; and
oversampling the one or more PRS transmissions.