Patent Publication Number: US-2022229145-A1

Title: Bandwidth parts for positioning signals

Description:
TECHNICAL FIELD 
     Various examples of the invention generally relate to positioning of wireless communication devices using positioning signals transmitted by multiple access nodes. Various examples specifically relate to using bandwidth parts to transmit the positioning signals. 
     BACKGROUND 
     To facilitate positioning of wireless communication devices (sometimes also referred to as user equipment, UE), multilateration and multiangulation techniques can be employed. An example of multiangulation is triangulation. Here, multiple access nodes (AN)—having a well-defined position in a reference coordinate system—transmit positioning signals (also referred to as positioning reference signals, PRSs). A UE can receive the PRSs and then trigger a multilateration or multiangulation. One particular technique is observed time-difference of arrival (OTDOA). 
     OTDOA is, in particular, deployed in Third Generation Partnership (3GPP) cellular networks, such as the Long Term Evolution (LTE) 4G or New Radio (NR) 5G protocols. Here, the UE receives PRSs from multiple base stations (BSs) implementing the ANs and then performs a timing difference of arrival (TDOA) measurement. Results of the TDOA measurements are transmitted from the UE to a location server (LS) using a positioning protocol (PP). This is via the 3GPP radio access network (RAN). The LS then performs the positioning estimation based on multilateration and/or multiangulation of at least two or at least three results of the TDOA measurements. See 3GPP Technical specification (TS) 36.305, V15.0.0 (2018-07), section 4.3.2. 
     In the 3GPP LTE protocol, the PRSs have a defined resource mapping to time-frequency resource elements of a resource grid. For example, reference is made to 3GPP TS 36.211, section 6.10.4, FIG. 6.10.4.2-1 (here reproduced as  FIG. 16 ): here, the resource mapping is illustrated for both one or two transmit antenna ports, and four antenna ports. The resource mapping has a diagonal pattern. The resource mapping allocates time-frequency resources for the PRSs every sixth subcarrier and therefore, it supports a reuse factor of up to 6: up to six BSs could transmit using respective complimentary resource mappings. The complimentary resource mappings use time-frequency resources for the PRS transmission that are shifted in frequency domain and/or time domain within a common resource grid of a timeslot or subframe, so that the UE can receive all PRSs according to the complimentary resource mappings. The complimentary resource mappings implement time domain and frequency domain multiplexing within a common resource grid and common timeslot. A given subframe including two timeslots is dedicated, i.e., exclusively reserved, for PRS transmission. There are no other signals/channels within that subframe (except common reference signal (CRS)) to avoid interference. The PRS transmission is reconfigurable. It can be transmitted in the whole LTE system bandwidth. The PRS can be transmitted in N consecutive subframes with M PRS periodicity. N varies from 1 to 6 ms and M is from 160-1280 ms. The PRS is used by the UE to estimate time of arrival (TOA). 
     For PRSs transmission in 3GPP NR, see 3GPP R1-1905703. 
     Such techniques face certain restrictions and drawbacks. For example, a flexibility of transmitting the PRSs in view of a variable configuration of a wireless link supported by the 3GPP RAN can be limited. Then, the flexible configuration of the wireless link can be impaired by the need to accommodate for the PRSs. 
     In further detail, 3GPP NR supports multiple numerologies and thus subcarrier spacings. While 3GPP LTE only uses 15 kHz subcarrier spacing, different numerologies can be used in 3GPP NR depending on the use cases (e.g., eMBB, URLLC, mMTC). Since PRSs are received from multiple BSs for multilateration and/or multiangulation, the different numerologies can make it difficult to implement multiplexing in frequency domain and/or time domain across the multiple BSs. 
     SUMMARY 
     Therefore, a need exists for advanced techniques of transmitting PRSs. In particular, a need exists for advanced techniques which overcome or mitigate at least some of the above-identified restrictions or drawbacks. In particular, there is a need for techniques which facilitate PRSs transmission in communication systems supporting multiple numerologies. 
     This need is met by the features of the independent claims. The features of the dependent claims define embodiments. 
     A method of operating a UE includes receiving a configuration of multiple bandwidth parts. Each bandwidth part of the multiple bandwidth parts is associated with a respective access node of multiple access nodes. The method also includes receiving positioning signals on each bandwidth part of the multiple bandwidth part from the respectively associate access node of the multiple access nodes. Said receiving is in accordance with the configuration. The method also includes participating in positioning of the UW based on said receiving of the positioning signals. 
     A computer program or a computer-program product or a computer-readable storage medium includes program code to be executed by at least one processor. Executing the program code causes the at least one processor to perform a method of operating a UE. The method includes receiving a configuration of multiple bandwidth parts. Each bandwidth part of the multiple bandwidth parts is associated with a respective access node of multiple access nodes. The method also includes receiving positioning signals on each bandwidth part of the multiple bandwidth part from the respectively associate access node of the multiple access nodes. Said receiving is in accordance with the configuration. The method also includes participating in positioning of the UW based on said receiving of the positioning signals. 
     A UE includes control circuitry, the control circuitry being configured to: receive a configuration of multiple bandwidth parts, each bandwidth part of the multiple bandwidth parts being associated with a respective access node of multiple access nodes; and to receive, in accordance with the configuration, positioning signals on each bandwidth part of the multiple bandwidth parts from the respectively associated access node of the multiple access nodes; and to participate in positioning of the wireless communication device based on said receiving of the positioning signals. 
     A method of operating a network node of a network includes determining a configuration of one or more bandwidth parts for positioning signals. The positioning signals are to be transmitted by one or more access nodes of the network. The method also includes providing the configuration of the one or more bandwidth parts to one or more UEs. The method also includes triggering transmission of the positioning signals on the one or more bandwidth parts in accordance with the configuration. 
     A computer program or a computer-program product or a computer-readable storage medium includes program code to be executed by at least one processor. Executing the program code causes the at least one processor to perform a method of operating a network node of a network includes determining a configuration of one or more bandwidth parts for positioning signals. The positioning signals are to be transmitted by one or more access nodes of the network. The method also includes providing the configuration of the one or more bandwidth parts to one or more UEs. The method also includes triggering transmission of the positioning signals on the one or more bandwidth parts in accordance with the configuration. 
     A network node of a network includes control circuitry, the control circuitry being configured to: determine a configuration of one or more bandwidth parts for positioning signals to be transmitted by one or more access nodes of the network; and to provide the configuration of the one or more bandwidth parts to one or more wireless communication devices; and to trigger transmission of the positioning signals on the one or more bandwidth parts in accordance with the configuration. 
     For example, the network node could be a location server or one of the one or more access nodes. 
     It is to be understood that the features mentioned above and those yet to be explained below may be used not only in the respective combinations indicated, but also in other combinations or in isolation without departing from the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically illustrates a cellular network according to various examples. 
         FIG. 2  schematically illustrates a resource mapping of various channels implemented on a wireless link of the cellular network according to various examples. 
         FIG. 3  schematically illustrates bandwidth parts implemented on the wireless link of the cellular network according to various examples. 
         FIG. 4  schematically illustrates subcarriers of a carrier of the wireless link implementing Orthogonal Frequency Division Multiplexing. 
         FIG. 5  schematically illustrates transmission of PRSs according to various examples. 
         FIG. 6  schematically illustrates a BS according to various examples. 
         FIG. 7  schematically illustrates a UE according to various examples. 
         FIG. 8  schematically illustrates an LS according to various examples. 
         FIG. 9  is a flowchart of a method according to various examples. 
         FIG. 10  is a flowchart of a method according to various examples. 
         FIG. 11  is a schematic illustration of a mapping of BSs to bandwidth parts and UEs to bandwidth prats according to various examples. 
         FIG. 12  schematically illustrates multiple, complementary resource mappings according to various examples. 
         FIG. 13  is a signaling diagram according to various examples. 
         FIG. 14  schematically illustrates a timing of transmission of PRSs on bandwidth parts according to various examples. 
         FIG. 15  schematically illustrates a timing of transmission of PRSs on bandwidth parts according to various examples. 
         FIG. 16  schematically illustrates multiple, complementary resource mappings according to the prior art. 
         FIG. 17  schematically illustrates a configuration of multiple positioning bandwidth parts according to various examples. 
         FIG. 18  schematically illustrates a configuration of multiple positioning bandwidth parts according to various examples. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Some examples of the present disclosure generally provide for a plurality of circuits or other electrical devices. All references to the circuits and other electrical devices and the functionality provided by each are not intended to be limited to encompassing only what is illustrated and described herein. While particular labels may be assigned to the various circuits or other electrical devices disclosed, such labels are not intended to limit the scope of operation for the circuits and the other electrical devices. Such circuits and other electrical devices may be combined with each other and/or separated in any manner based on the particular type of electrical implementation that is desired. It is recognized that any circuit or other electrical device disclosed herein may include any number of microcontrollers, a graphics processor unit (GPU), integrated circuits, memory devices (e.g., FLASH, random access memory (RAM), read only memory (ROM), electrically programmable read only memory (EPROM), electrically erasable programmable read only memory (EEPROM), or other suitable variants thereof), and software which co-act with one another to perform operation(s) disclosed herein. In addition, any one or more of the electrical devices may be configured to execute a program code that is embodied in a non-transitory computer readable medium programmed to perform any number of the functions as disclosed. 
     In the following, embodiments of the invention will be described in detail with reference to the accompanying drawings. It is to be understood that the following description of embodiments is not to be taken in a limiting sense. The scope of the invention is not intended to be limited by the embodiments described hereinafter or by the drawings, which are taken to be illustrative only. 
     The drawings are to be regarded as being schematic representations and elements illustrated in the drawings are not necessarily shown to scale. Rather, the various elements are represented such that their function and general purpose become apparent to a person skilled in the art. Any connection or coupling between functional blocks, devices, components, or other physical or functional units shown in the drawings or described herein may also be implemented by an indirect connection or coupling. A coupling between components may also be established over a wireless connection. Functional blocks may be implemented in hardware, firmware, software, or a combination thereof. 
     Hereinafter, techniques which facilitate positioning of UEs are described. The techniques described herein generally rely on the transmission of PRSs. These PRSs are transmitted by multiple ANs and can be received by a target UE to be positioned. The ANs can have a well-defined position within a reference coordinate system and the target UE can be positioned within the reference coordinate system. 
     According to various examples described herein, transmission of the PRSs may be implemented on a wireless link on which also transmission of further signals is implemented. In particular, the further signals may encode, e.g., control messages or payload messages. The wireless link may operate according to a transmission protocol. For example, the transmission protocol may employ Orthogonal Frequency Division Multiplex (OFDM) modulation. Here, a carrier comprises multiple subcarrier and one or more associated time-frequency resource grids are defined. For example, the transmission protocol may be associated with a RAN of a cellular network; here, the ANs can be implemented by BSs of the RAN. 
     According to the various techniques described herein, the positioning may employ a multilateration and/or multiangulation based on one or more receive properties of the PRSs transmitted by multiple ANs. It would be possible that the logic for implementing said positioning partly or fully resides at the UE to be positioned, and/or partly or fully resides at a LS. For example, it would be possible that the UE reports raw measurement data associated with the one or more receive properties of the PRSs to the LS and that the multilateration and/or multiangulation is implemented at the LS. It would also be possible that at least a part of the processing of the multilateration and/or multiangulation etc. is implemented at the UE. The positioning may generally comprise OTDOA. 
     In the techniques described herein, the concepts of PRS transmission are combined with concepts of bandwidth parts (BWPs). In general, different BWPs may be employed, depending on the payload size and traffic or signal type, for power saving purposes. For example, the UE can use a narrow BWP for monitoring control channels and only open the full bandwidth of the carrier when a large amount of data is scheduled. 
     Various techniques herein are based on the finding that it can be helpful to implement transmission of PRSs on one or more associated BWPs (hereinafter, positioning BWPs, P-BWPs). As a general rule, it would be possible that the one or more P-BWPs are exclusively reserved for the transmission of the PRSs; or that the one or more P-BWPs are shared between the transmission of the PRSs and the transmission of one or more further signals. 
     According to various examples, a UE receives PRSs on multiple P-BWPs from multiple BSs. Each P-BWP is associated with a respective one of the multiple BSs. Thus, the P-BWPs are cell specific for the cell supported by the respective BSs. A corresponding configuration of the multiple P-BWPs may be provided to the UE. As a general rule, P-BWPs are characterized with respect to their numerology, i.e., subcarrier spacing (SCS). Thus, the configuration can be indicative of the numerologies of the P-BWPs. 
     Alternatively or additionally, the configuration could also be indicative of further configuration parameters of the P-BWPs. To name a few examples: frequency; transmission timing; puncturing of PRS transmission on a given P-BWP; activation or deactivation of a given P-BWP. 
     Next, details with respect to the relationship between the multiple P-BWPs will be explained: 
     As a general rule, it would be possible that the configuration of the multiple P-BWPs is indicative of common configuration parameters for at least some of the multiple P-BWPs, i.e., shared P-BWPs can be defined. For example, shared P-BWPs that are associated with the multiple BSs may use the same common frequency, the same common numerology, the same common transmission timing, and the same common antenna port. 
     It would also be possible that the configuration of the multiple P-BWPs is indicative of at least partially different configuration parameters for at least some of the multiple P-BWPs. For example, where two P-BWPs have at least partially different configuration parameters, the may use different frequency, different numerologies, different transmission timings, and/or different antenna ports. Hence, other P-BWPs may be used. 
     In the various examples described herein, the P-BWPs may be flexibly adapted. In other words, it becomes possible to flexibly determine and set the configuration of the P-BWPs. For example, at least one of a numerology (e.g., subcarrier spacing, SCS, of subcarriers of an OFDM carrier), frequency bandwidth or frequency position, and/or transmission timing of the P-BWPs can be flexibly set, to give just a few examples of possible configuration parameters that are subject to a respective configuration of the P-BWPs. It would also be possible to activate/deactivate a given P-BWP. For example, A BS can deactivate P-BWP and use it for other purposes, such as data communication or just simply not transmit at all to transmit lean carrier. The UE is expected to use P-BWP from other BSs. 
     Such use of P-BWPs helps to facilitate supporting a flexible transmission settings and, in particular, flexible numerology for different BSs of a cellular network. For example, the following scenario would be possible: There are six BSs and two BSs use numerology A and four BSs use numerology B. Then, the two BSs can use first shared P-BWPs having numerology A and the four BSs can use second shared BWPs having numerology B. The PRSs are transmitted by the two BSs on the respective first shared P-BWPs using complimentary resource mappings, i.e., using time-frequency resources that are offset within the same resource grid in the same timeslots. Likewise, the PRSs are transmitted by the four BSs on the respective second shared P-BWPs using further complimentary resource mappings. In such a scenario, once a UE in a cell knows the P-BWP(s) used by that cell, it can expect the availability of PRS or P-BWPs from multiple cells. 
       FIG. 1  schematically illustrates a cellular network  100 . The example of  FIG. 1  illustrates the network  100  according to the 3GPP 5G architecture. Details of the 3GPP 5G architecture are described in 3GPP TS 23.501, version 1.3.0 (2017-09). While  FIG. 1  and further parts of the following description illustrate techniques in the 3GPP 5G framework of a cellular network, similar techniques may be readily applied to other communication networks. Examples include e.g., an IEEE Wi-Fi technology. 
     In the scenario of  FIG. 1 , a UE  101  is connectable to the cellular network  100 . For example, the UE  101  may be one of the following: a cellular phone; a smart phone; and IOT device; a MTC device; a sensor; an actuator; etc. 
     The UE  101  is connectable to the network  100  via a RAN  111 , typically formed by one or more BSs  112  (only a single BS  112  is illustrated in  FIG. 1  for sake of simplicity; the BSs implement ANs). A wireless link  114  is established between the RAN  111 —specifically between one or more of the BSs  112  of the RAN  111 —and the UE  101 . The wireless link  114  is defined by one or more OFDM carriers. 
     The RAN  111  is connected to a core network (CN)  115 . The CN  115  includes a user plane (UP)  191  and a control plane (CP)  192 . Application data is typically routed via the UP  191 . For this, there is provided a UP function (UPF)  121 . The UPF  121  may implement router functionality. Application data may pass through one or more UPFs  121 . In the scenario of  FIG. 1 , the UPF  121  acts as a gateway towards a data network  180 , e.g., the Internet or a Local Area Network. Application data can be communicated between the UE  101  and one or more servers on the data network  180 . 
     The network  100  also includes an Access and Mobility Management Function (AMF)  131 ; a Session Management Function (SMF)  132 ; a Policy Control Function (PCF)  133 ; an Application Function (AF)  134 ; a Network Slice Selection Function (NSSF)  134 ; an Authentication Server Function (AUSF)  136 ; a Unified Data Management (UDM)  137 ; and a Location Management Function (LMF)  139 .  FIG. 1  also illustrates the protocol reference points N 1 -N 22  between these nodes. 
     The AMF  131  provides one or more of the following functionalities: registration management; NAS termination; connection management; reachability management; mobility management; access authentication; and access authorization. A data connection  189  is established by the AMF  131  if the respective UE  101  operates in a connected mode. 
     The SMF  132  provides one or more of the following functionalities: session management including session establishment, modify and release, including bearers set up of UP bearers between the RAN  111  and the UPF  121 ; selection and control of UPFs; configuring of traffic steering; roaming functionality; termination of at least parts of NAS messages; etc. As such, the AMF  131  and the SMF  132  both implement CP mobility management needed to support a moving UE. 
     The data connection  189  is established between the UE  101  via the RAN  111  and the data plane  191  of the CN  115  and towards the DN  180 . For example, a connection with the Internet or another packet data network can be established. To establish the data connection  189 , it is possible that the respective UE  101  performs a random access (RACH) procedure, e.g., in response to reception of a paging indicator or paging message and, optionally, a preceding WUS. A server of the DN  180  may host a service for which payload data is communicated via the data connection  189 . The data connection  189  may include one or more bearers such as a dedicated bearer or a default bearer. The data connection  189  may be defined on the RRC layer, e.g., generally Layer 3 of the OSI model of Layer 2. 
     The LMF  139  is implemented by LS. The LMF  139  handles location service requests. This may include transferring assistance data to the target UE  101  to be positioned to assist with UE-based and/or UE-assisted positioning and/or may include positioning of the target UE. See 3GPP TS 38.305 V15.3.0 (2019-03), section 5.1. For downlink (DL) positioning using PRSs, the LMF  139  may instigate location procedures using a positioning protocol with the UE  101 —e.g. to obtain a location estimate or positioning measurements or to transfer location assistance data to the UE  101 . The LMF  139  can transmit a configuration regarding BWPs to the UE  101 . 
       FIG. 2  illustrates aspects with respect to channels  261 - 263  implemented on the wireless link  114 . The wireless link  114  implements a plurality of channels  261 - 263 . The resources of the channels  261 - 263  are offset from each other, e.g., in frequency domain and/or time domain, in accordance with a respective resource mapping. The resources may be defined in a time-frequency grid defined by the symbols and subcarriers of the OFDM modulation of the carrier. 
     A first channel  261  may carry PRSs. 
     A second channel  262  may carry further reference signals, e.g., Channel State Indication reference signals (CSI-RS), Demodulation reference signals (DMRS), or synchronization reference signals (PSS/SSS), etc. 
     Further, a third channel  263  is associated with a payload messages carrying higher-layer user-plane data packets associated with a given service implemented by the UE  101  and the BS  112  (payload channel  263 ). User-data messages may be transmitted via the payload channel  263 . Alternatively, control messages may be transmitted via the channel  263 , e.g., control messages of a positioning protocol. For example, a configuration of BWPs used for PRS transmission may be included in the control messages of the PP. 
       FIG. 3  illustrates aspects in connection with a carrier  370  of the wireless link  114 .  FIG. 3  schematically illustrates a bandwidth  380  of the carrier  370 . For example, the carrier  370  can operate according to OFDM and can include multiple subcarriers (not illustrated in  FIG. 3 ). 
       FIG. 3  further illustrates aspects of BWPs  371 - 372 . The BWPs  371 - 372 , respectively, occupy an associated subfraction of the overall bandwidth  380 . The BWP  372  includes a sub-BWP  373 , having a smaller BW and being associated with the BWP  372 . 
     For example, allocation of resource elements of the time-frequency grid for transmission of various signals, including PRSs, can be relatively defined with respect to the respective BWP  371 - 373 . Each BWP  371 - 373  can be defined as a subset of continuous and contiguous common physical resource blocks (PRBs), each PRB defining a set of resources in the time-frequency grid. A receiver of the UE  101 , if configured to monitor, e.g., the BWP  371 , can limit its receive bandwidth correspondingly. As a general rule, each BWP  371 - 372  and sub-BWP  373  each can have a unique OFDM numerology. As illustrated in  FIG. 3 , the BWP  371  implements a first numerology  801 ; while the BWP  372  and the sub-BWP  373  implement a second numerology  802 . By switching between different BWPs, the wireless system can dynamically switch between different frequency bandwidths being utilized for communicating with the different UEs or different channels. Also, by the use of different numerologies in different BWPs, different QoS levels may be achieved due to the numerology relation to the OFDM symbol length. 
     As a general rule, there are various parameters conceivable that are affected by the respective setting of the OFDM numerology  801 ,  802 . To give a few examples, the SCS of subcarriers of the carrier  370  can vary. Also, the number of time slots per subframe can depend on the setting of the OFDM numerology  801 ,  802 . For example, the number of OFDM symbols per time slot can thereby vary along with the change of the settings of the OFDM numerology  801 ,  802 . The cyclic prefix length can vary with the change of SCS. In a further example, the time division duplex (TDD) partitioning can vary, depending on the setting of the numerology  801 ,  802 . To give an example, the SCS may vary between 15 kHz and 120 kHz, e.g., in four different numerology settings. 
       FIG. 4  illustrates aspects with respect to communicating on the wireless link  114 . Specifically,  FIG. 4  illustrates aspects with respect to modulation of signals to be communicated on the wireless link  114 . 
     Specifically,  FIG. 4 , upper part, illustrates multiple subcarriers  811 - 813  in frequency domain used for OFDM modulation. Different subcarriers  811 - 813  are orthogonal with respect to each other and thus can each encode specific information with reduced interference. As a general rule, OFDM modulation may employ a variable count of subcarriers  811 - 813 , e.g., between twenty and two thousand subcarriers. The count of subcarriers can carry as a setting of the OFDM numerology  801 ,  802 .  FIG. 4  also illustrates the SCS  805  of the current setting of the OFDM numerology  801 ,  802 . 
     As will be appreciated from  FIG. 4 , different SCSs  805  result in different time-frequency resource grids. Accordingly, where different BSs employ different SCS  805 , it is sometimes difficult to obtain complimentary resource mappings that allow frequency reuse across the multiple BSs for transmission of PRSs. The techniques described herein mitigate these problems by using P-BWPs for the transmission of PRSs and by assigning a specific numerology to each P-BWP. Shared P-BWPs may use the same numerology; while multiple P-BWPs may be used to accommodate for different numerologies. Next, details with respect to such downlink (DL) positioning techniques using PRSs are explained in connection with  FIG. 5 . 
       FIG. 5  schematically illustrates aspects with respect to DL positioning techniques for a target UE  101  to be positioned. Multiple BSs  112 - 1 - 112 - 4  transmit DL PRSs  150  and the UE  101  receives the PRSs  150 . Then, the UE  101  can participate in positioning. This can include determining one or more receive properties of the PRSs  150 , determining a TOA of the PRSs  150 , determining a TDOA of the PRSs  150 , and/or performing multilateration and/or multiangulation based on the TDOA. At least some of these tasks can also be performed by the LMF  139  or, more generally, an LS. 
       FIG. 6  schematically illustrates the BS  112 . For example, the BSs  112 - 1 - 112 - 4  could be configured accordingly. The BS  112  includes an interface  1121 . For example, the interface  1121  may include an analog front end and a digital front end. The interface  1121  can support multiple signal designs, e.g., different modulation schemes, coding schemes, modulation numerologies, and/or multiplexing schemes, etc. Multiple BWPs are supported. The BS  112  further includes control circuitry  1122 , e.g., implemented by means of one or more processors and software. For example, program code to be executed by the control circuitry  1122  may be stored in a non-volatile memory  1123 . 
     In the various examples disclosed herein, various functionality may be implemented by the control circuitry  1122 , e.g.: determining a configuration of one or more BWPs including one or more P-BWPs; adapting one or more BWPs, in particular P-BWPs; transmitting PRS on the one or more P-BWPs in accordance with the configuration; etc. 
       FIG. 7  schematically illustrates the UE  101 . The UE  101  includes an interface  1011 . For example, the interface  1011  may include an analog front end and a digital front end. The UE  101  further includes control circuitry  1012 , e.g., implemented by means of one or more processors and software. The control circuitry  1012  may also be at least partly implemented in hardware. For example, program code to be executed by the control circuitry  1012  may be stored in a non-volatile memory  1013 . In the various examples disclosed herein, various functionality may be implemented by the control circuitry  1012 , e.g.: receiving a configuration of one or more BWPs, including one or more P-BWPs; switching between different BWPs including P-BWPs; implementing measurement gaps for receiving PRSs; receiving PRSs on the P-BWPs in accordance with the configuration; participating in a positioning of the UE  101  based on one or more receive properties of the PRSs, e.g., including determining TOAs of the PRSs, determining TDOA, multilateration and/or multiangulation. A receive bandwidth with which the PRSs are received may depend on at least one of an accuracy of said positioning or a receiver bandwidth capability of the UE  101 . 
       FIG. 8  schematically illustrates an LS that implements, in the example of  FIG. 8 , the LMF  139 . The LMF  139  includes an interface  1391  for communicating with other nodes of the CN  115  or with the RAN  111  of the cellular network  100 . The LMF  139  further includes control circuitry  1392 , e.g., implemented by means of one or more processors and software. For example, program code to be executed by the control circuitry  1392  may be stored in a non-volatile memory  1393 . In the various examples disclosed herein, various functionality may be implemented by the control circuitry  1392 , e.g.: determining a configuration of one or more BWPs including one or more P-BWPs; providing the configuration to one or more UEs  101 ; providing the configuration to one or more BSs  112 ,  112 - 1 - 112 - 4  of the RAN  111 ; participating in positioning of a UE  101 , e.g., based on one or more receive properties of the PRSs such as TOA or TDOA, etc. 
       FIG. 9  is a flowchart of a method according to various examples. The method of  FIG. 9  can be executed by a node of a communication network, e.g., by a node of the cellular network  100  (cf.  FIG. 1 ). For example, the method of  FIG. 9  could be implemented by a BS  112 ,  112 - 1 - 112 - 4  of the RAN  111 ; however, it would also be possible that the method of  FIG. 9  is implemented by the LMF  139  or another node of the cellular network  100 . For example, the method of  FIG. 9  may be executed by the control circuitry  1122  of the BS  112  or the control circuitry  1392  of the LMF  139  upon loading program code from the memory  1123  or  1393 , respectively. 
     Initially, at box  1001 , a configuration of one or more P-BWP that are associated with a respective BS is determined. The one or more P-BWPs are for PRSs transmission by the respective BS to one or more UEs. Thus, the one or more P-BWPs are cell-specific for the cell associated with the respective BS. 
     For example, if the BS is capable of wideband transmission, multiple P-BWPs can be associated with that BS, wherein the multiple P-BWPs can be in multiple component carriers (CC). 
     As a general rule, the one or more P-BWPs could be exclusively reserved for the transmission of the PRSs. I.e., in a scenario in which a P-BWP exclusively reserved for the transmission of the PRSs, no further signals are allocated to time-frequency resources of the P-BWP. 
     In some examples, to determine the configuration, it would be possible that one or more further configurations of one or more further P-BWPs of one or more further BSs are taken into account. For example, core network control signaling or inter-BS control signaling can be used to obtain the one or more further configurations. Then, it would be possible that the configuration of the one or more P-BWPs is determined such that the P-BWP is compatible with the one or more further P-BWPs. This facilitates reception of the PRSs from the various BS at the UE and hence facilitates accurate positioning. For example, shared P-BWPs could be determined that use common configuration parameters, e.g., the same numerology, transmission timing, frequency, antenna port configuration, beam configuration, etc. In other examples, different P-BWPs could be determined that use different configuration parameters. These findings are explained in detail below: 
     As a general rule, it would be possible that the one or more further P-BWPs used for PRS transmission by the one or more further BSs are different if compared to the one or more P-BWPs used for PRS transmission by the BS. For example, the one or more further P-BWPs may have a different bandwidth if compared to the one or more P-BWPs. For example, frequency multiplexing and/or time multiplexing may be used: i.e., the transmission timing and/or the frequency of the one or more P-BWPs may be offset, but aligned accordingly with the transmission timing and/or frequency of the one or more further P-BWPs. The one or more further P-BWPs and the one or more P-BWPs may use different numerologies. 
     Alternatively, it would also be possible that the one or more further P-BWPs used for PRS transmission by the one or more further BSs are the same than the one or more P-BWPs used for PRS transmission by the BS. In other words, in some examples, it would be possible that a reuse of a common time-frequency grid of P-BWP is implemented (shared P-BWPs), by using a common numerology, a common frequency and a common transmission timing. Here, complimentary resource mappings can be used for the PRS transmission on the shared P-BWPs. 
     As a general rule, where complimentary resource mappings are used, the time-frequency resources allocated to the transmission of the PRSs on different P-BWPs can be defined offset with respect to each other in the same time-frequency resource grid of a given time slot or subframe. I.e., a reuse factor of two, three, etc. could be defined. The multiple resource mappings can have the same starting position, i.e., the beginning of the same timeslot or subframe. This also facilitates receiving PRSs on multiple P-BWPs. The complimentary resource mapping is explained later on in detail with respect to  FIG. 12 . 
     Further options for aligning the PRS transmission between shared P-BWPs include: PRSs can be transmitted on the one or more P-BWPs using a common antenna port configuration if compared to the PRSs transmitted on the one or more further P-BWPs of the one or more further BSs. 
     As a general rule, different antenna ports can be associated with different time-frequency resource grids. For example, different antenna ports may be associated with different resource element mappings. By using the same antenna port for different P-BWPs, the UE can receive the PRSs across the different P-BWPs with a single OFDM demodulation process at the wireless interface. Thus, the UE can receive PRSs on multiple P-BWPs and utilize said receiving for positioning, e.g., using OTDOA. 
     Further options for aligning the PRS transmission between multiple P-BWPs include: using a common beam configuration. Here, similar propagation characteristics can be defined for the PRS transmission across the various P-BWPs. 
     Sometimes, a BS may need to transmit PRSs on multiple beams, e.g., to provide larger coverage. Different beams may be associated with different resource element mappings, e.g., within a shared P-BWP. In case, there are multiple shared P-BWP in different frequency allocation, having common beam configuration would be beneficial for the UE so that it can simultaneously process the received multiple shared P-BWP in order to obtain higher accuracy. 
     Next, at box  1002 , the configuration of the one or more P-BWPs is provided to the UE. This may involve control signaling between the BS and the LMF  139 . For example, the configuration may be forwarded to the LMF  139  and the LMF  139  may then pass the configuration onwards to the UE  101 , via the RAN  111  using the channel  263 , e.g., including PP control messages. 
     At box  1003 , transmission of PRSs on the one or more P-BWPs is triggered. This can include controlling the wireless interface appropriately. The LMF may instruct the BS to transmit the PRSs. The transmission of the PRSs is in accordance with the configuration determined at box  1001 . The PRSs may be transmitted on the channel  261 . 
       FIG. 10  is a flowchart of a method according to various examples. The method of  FIG. 10  can be executed by a UE. For example, the method of  FIG. 10  could be implemented by the UE  101  connected or connectable to the RAN  111 . For example, the method of  FIG. 10  may be executed by the control circuitry  1012  of the UE  101  upon loading program code from the memory  1013 . 
     At box  1011 , a configuration of multiple P-BWPs is received. The multiple P-BWPs are associated with multiple BSs, i.e., with multiple cells of the multiple BSs. The P-BWPs are thus cell-specific. 
     For example, a single BS may transmit PRSs on multiple P-BWPs or on a single P-BWP. It would also be possible that multiple BSs use shared P-BWPs, e.g., by using complimentary resource mappings with a reuse factor corresponding to the count of BSs. It would also be possible that multiple BSs transmit PRSs on different P-BWPs. 
     The configuration can be generally indicative of a mapping of the multiple P-BWPs to identities of the BSs. I.e., the UE can determine which one of the one or more BSs uses which one of the multiple P-BWPs. This can be used in the positioning and when monitoring for the PRSs. In other words, the configuration can be generally indicative of a mapping of the multiple P-BWPs to identities of one or more cells associated with a respective one of the one or more BSs. 
     For example, at box  1011 , a respective control message may be received on the channel  263 . For example, the control message may include an information element according to the positioning protocol. The configuration may be generally received from the LMF  139  via control signaling on the RAN  111 . 
     Box  1011  is interrelated to box  1002  (cf.  FIG. 9 ). 
     Next, at box  1012 , PRSs are received on the P-BWPs in accordance with the configuration received at box  1011 . By receiving the PRSs on the multiple P-BWPs associated with multiple BSs, it becomes possible to receive PRSs from multiple BSs and, thereby, increase the accuracy of the positioning. For example, the accuracy of the multilateration and/or multiangulation can benefit if a larger count of reference positions, corresponding to the BSs transmitting the PRSs, is considered. 
     Next, at box  1013 , the UE participates in positioning. This can include determining a TOA, TDOA, OTDOA. This can include performing or triggering a multilateration and/or multiangulation. Box  1013  can include control signaling between the UE and the LMF  139 . For example, the LMF  139  can assist the UE in the task of multilateration and/or multiangulation or other tasks of the positioning. 
     The techniques of  FIG. 9  and  FIG. 10  thus enable support PRS transmission with multiple numerologies—i.e., on the multiple P-BWPs—and an efficient way to multiplex the PRS transmissions—i.e., on the multiple P-BWPs—so that a UE can receive the PRSs and utilize them for positioning. By using P-BWPs, further BWPs not used for PRS transmission can be flexibly configured. In particular, multiple BSs may use shared P-BWPs or time/frequency aligned P-BWPs which imposes certain constraints on the configuration of the P-BWPs. These constraints could otherwise conflict with the transmission of further signals other than the PRS. By using the P-BWPs, it is possible to obey these constraints and, at the same time, flexibly transmit the further signals. Details with such inter-working of multiple BSs in terms of P-BWPs are described in connection with  FIG. 11 . 
       FIG. 11  is a schematic illustration of a mapping between BSs  112 - 1 - 112 - 3  and P-BWPs  601 - 604 . Each of the P-BWPs  601 - 604  can be implemented as explained for the BWPs  371 - 372  in  FIG. 3 , but for the purpose of transmitting PRSs. 
     In the example of  FIG. 11 , the BS  112 - 1  is mapped to the P-BWP  601 ; the BS  112 - 2  is mapped to, both, the P-BWP  602 ,  603 , and the BS  112 - 3  is mapped to the P-BWP  604 . As will be appreciated, in the example of  FIG. 11 , the BWPs  601 - 604  are cell-specific. Thus, the BSs  112 - 1 - 112 - 4  need to interwork to agree on these BWPs  601 - 604 , e.g., their frequency position and frequency bandwidth (frequencies) and transmission timing, etc. 
     The P-BWPs  601 ,  602  have the same numerology  801  and frequency. For example, they may also have the same transmission timing (not illustrated in  FIG. 11 ) and thus be shared P-BWPs. Similar observations apply to the P-BWPs  603 ,  604 . 
     Now assuming that the P-BWPs  601 ,  602  are shared: to avoid collision of the transmission of the PRSs on the shared P-BWPs  601 ,  602 , the PRSs are transmitted by the BS  112 - 1  and the BS  112 - 2  using a common antenna port configuration and using complimentary resource mappings. This is illustrated in  FIG. 12 .  FIG. 12  is comparable with  FIG. 16  (prior art).  FIG. 12  illustrates a simplified version of  FIG. 16 .  FIG. 12  illustrates time-frequency resource elements for two timeslots  298 ,  299 , the two timeslots forming a subframe. 
     In the concrete case of  FIG. 12 , a reuse factor of two is implemented: the BS  112 - 1  and the BS  112 - 2  use the same time-frequency resource grid within the timeslots  298 ,  299 ; the resource elements  271 ,  272  used by each one of the BSs  112 - 1 ,  112 - 2 , respectively, to transmit the PRSs  150  are offset in frequency domain by a single time-frequency resource element. As already specified above, the reuse factor specifies the count of BSs accessing the same time-frequency resource grid with complimentary resource mappings to transit the PRSs. The allocation used by the shared P-BWPs  601 ,  602  could accommodate for a reuse factor of, e.g., five—if further BSs were mapped to the allocation of the P-BWPs  601 ,  602 . Note that the diagonal pattern of the resource elements  271 ,  272  is repeated every fifth symbol. Thus, up to five BSs could use complimentary resource mappings. 
     Referring again to  FIG. 11 , different ones of the UEs  101 - 1 - 101 - 4  receive PRSs on different ones of the BWPs  601 - 604 . For example, this can include checking, at the UEs  101 - 1 - 101 - 4 , whether a respective BSs  112 - 1 - 112 - 3  is in coverage. 
     As a general rule, the various UEs  101 - 1 - 101 - 4  can be configured individually by the LMF  139 ; or using broadcast control signaling. 
     Next, details with respect to such signaling between the various participating entities—e.g., the BS  112 , the UE  101 , and the LMF  139 —are explained in connection with  FIG. 13 . 
       FIG. 13  is a signaling flowchart illustrating communication between the BSs  112 - 1 - 112 - 3  (cf.  FIG. 11 ) of the RAN  111 , the LMF  139  and the UEs  101 - 1 - 101 - 4  (cf.  FIG. 11 ). For example, the signaling of  FIG. 13  could implement the methods according to  FIG. 9  and  FIG. 10 . 
     Initially, at  4001 , the BSs  112 - 1 - 112 - 4  provide a configuration  3001  of the P-BWPs  601 - 604  to the LMF  139 . Each BSs  112 - 1 - 112 - 4  may provide its respective part of the configuration  3001 . To facilitate the UE  101  listening for the PRSs  150  transmitted by a given BS  112 - 1 - 112 - 4 , the configuration  3001  can be indicative of a mapping of the multiple P-BWPs  601 - 604  to the identities of the BSs  112 - 1 - 112 - 3 . Details of the mapping have been explained in connection with  FIG. 11 . 
     Optionally, the BSs  112 - 1 - 112 - 4  could also provide a setting  3002  of the PRSs  150  to be transmitted on the one or more P-BWPs  601 - 604  to the LMF  139 . Examples of such setting  3002  include: transmission power; resource mapping of PRSs; antenna port; and/or transmission beam. 
     Next, at  4002 , the LMF  139  provides the configuration  3001  and, optionally, the setting  3002  to the UEs  101 - 1 - 101 - 4 .  4002  could include broadcast signaling. 
     For example, the control signaling at  4002  may be implemented using a positioning protocol. Examples include an LTE positioning protocol Protocol Data Unit (LPP PDU) transmitted between the LMF  139  and the UE  101  according to 3GPP TS 38.305 V15.3.0 (2019-03), section 6.4.2. In further detail, a NR PP A PDU (NRPPa PDU) according to 3GPP TS 38.305 V15.3.0 (2019-03), section 6.5.2 may be used to implement the control signaling at  4002 . 
     As a general rule, various options are available for implementing the configuration  3001 . For example, the configuration  3001  could be indicative of modulation numerologies  801 ,  802 —e.g., SCS—of the P-BWPs  601 - 604 . Different P-BWPs  601 - 604  can have the same or different numerologies  801 ,  802 . 
     Also, the configuration  3001  could be used to indicate whether a P-BWP  601 - 604  is activated or deactivated. As a general rule, P-BWPs can be disabled and enabled by a BS: in  FIG. 11 , the BS  112 - 4  disables all P-BWPs and thus does not transmit PRSs  150 . Such techniques are based on the finding that, in reference implementations, PRS  150  are periodically transmitted by the BS with no option to disable PRS transmission. This may not be efficient particularly in a case where there is no demand for positioning services. The techniques described herein support a lean carrier where the target is to minimize any periodic/broadcast signal from a BS. For this, a BS may disable/enable the PRS transmission. The BS can provide information on the activation/deactivation as part of the configuration  3001  to the LMF  139  which can then inform the UE  101  accordingly. In the context of OTDOA: in case the configured reference cell deactivates PRS transmission, the LMF  139  can provide a new reference to the UE or the UE can provide suggested reference cell, e.g. the cell which produces smallest TDOA. 
     Multiple P-BWPs can be multiplexed in both time domain and frequency domain (cf.  FIG. 11  where frequency multiplexing of the P-BWPs  601 ,  602  with the P-BWPs  603 ,  604  in frequency domain is depicted). To this respect, it would be possible that the configuration  3001  is indicative of a frequency of the multiple positioning bandwidth parts  601 - 604 . Such frequency multiplexing can facilitate simultaneous transmission timings of the P-BWPs: the UE  101  can receive the PRS on the frequency-multiplexed P-BWPs simultaneously. This helps to shorten the time required for PRS transmission. Also, a temporal resolution of the positioning is high. 
     As a general rule, the transmission timings may be expressed in a common time base or reference time base. For example, system frame number (SFN), subframe numbers could be used to specify the transmission timing. 
     The transmission timing of the P-BWPs may also configure a time multiplexing: here, transmission of the PRSs on the multiple P-BWPs may be offset in time domain. Thus, alternatively or additionally, it would be possible that the configuration is indicative of a transmission timing of the multiple P-BWPs  601 - 604 . This means that the PRSs may be transmitted in accordance with a certain timing on the P-BWPs  601 - 604 . To give an example, it would be possible that the transmission timing is in accordance with a repetitive measurement gaps of a transmission protocol implemented on the wireless link  114  of the RAN  111 . This is illustrated in  FIG. 14 : here, the measurement gap  390  is defined and the PRSs are transmitted on the P-BWPs  605 ,  606  time-sequentially, i.e., time multiplexed (on the other hand, the P-BWPs  605 ,  607  have a synchronized transmission timing; the P-BWPs  605 - 607  illustrated in time-domain in  FIG. 14  and  FIG. 15  can correspond to the P-BWPs  601 - 604  illustrated in frequency-domain in  FIG. 11 . 
     As a general rule, to accommodate the PRS transmission on the multiple, time-multiplexed P-BWPs  605 - 606 , a duration of the measurement gap  390  can be dimensioned sufficiently long, e.g., including multiple consecutive subframes. 
     If the P-BWPs  605 - 606  employ different numerologies  801 ,  802 , it is possible to switch between different receiver settings or receiver bandwidths at the receiving UE  101  during a switching time  395 . Thus, a respective time-offset may be provisioned between the transmission timings of the P-BWPs  605 - 606 . 
     Outside the measurement gap  390 , further signals—e.g., on the channel  262  or the channel  263 —are transmitted; these further signals are not transmitted during the measurement gap  390 . During the measurement gaps  390 , the further signals—different from PRSs and, e.g., encoding control messages or payload data—are not be transmitted, to mitigate interference and increase positioning accuracy. Thus, there may be reserved timeslots or subframes—implementing the measurement gap  390 —during which the transmission of the PRSs on the P-BWPs is activated. In case there are further signals to be transmitted during the measurement gap  390 , the measurement gaps  390  may be punctured by an intermittent time gap  391  during which further signals are transmitted, but PRSs transmission on the P-BWPs  605 - 607  is temporarily suspended (cf.  FIG. 15 ). This information on such puncturing can also be included in the configuration  3001 . 
     The duration of the measurement gap  390  can generally depend on an accuracy requirement of the positioning. For example, if a higher accuracy is required, then a longer measurement gap  390  can be used. The transmission timings of the P-BWPs  605 - 607  can be adjusted: longer transmission of PRSs becomes possible. The accuracy may be signaled to a BS by a UE; or may be defined by the BS. In another example, the measurement gap  390  may be UE specific. In this case, a UE with higher accuracy requirement is configured with longer measurement gap. The transmission timings of the P-BWPs  605 - 607  can be fixed/limited. Thus, UEs with a shorter measurement gap  390  may only listen to a fraction of the overall PRS transmission. Some BSs can be configured to extend PRS transmission within that measurement gap. Such techniques help to conserve energy at the UE. 
     Similar considerations also apply to the frequency domain: e.g., the frequency bandwidth of the P-BWPs ca depend on the accuracy requirement of the positioning. If a higher accuracy is required, then a wider bandwidth can be used. Some BSs can be configured to extend bandwidth of PRS transmission. It would be possible that UEs only listen for PRSs on a fraction of the overall bandwidth of the P-BWPs. Such techniques help to conserve energy at the UE. 
     Summarizing, various techniques are based on the finding that—in order to support positioning measurements at the UE—, the UE needs to receive PRSs from multiple BSs. 3GPP NR supports multiple numerologies, i.e., SCSs, and sometimes it may become problematic to multiplex PRSs from multiple BSs. Above, an efficient scheme to multiplex PRSs that may have different numerologies so that the UE can utilize those PRS simultaneously to enhance positioning accuracy. Different P-BWPs can be used to implement different numerologies. Furthermore, the proposed scheme can also support lean-carrier operation where the PRS transmission can be disabled/enabled by the network. 
     The techniques described above facilitate introducing P-BWPs that support multiple numerologies. In case of the availability of multiple P-BWPs, the P-BWP share some parameters—e.g., alignment in time domain and frequency domain—and thus the can utilize more PRSs received on more than one P-BWP. A BS can enable/disable transmission of PRSs on a P-BWP or can even enable/disable a P-BWP altogether. The UE can be generally informed on the P-BWP configuration by control signaling of a positioning protocol and/or broadcast messages. For example, the UE can be informed whether there is a collision of PRS transmission on a P-BWP with other signals/channels. Then, the PRS transmission can be punctured accordingly. 
       FIG. 17  and  FIG. 18  illustrate aspects with respect to the configuration  3001 . In  FIG. 17  and  FIG. 18  two possible implementations for providing the configuration  3001  for the P-BWPs  601 ,  602  (cf.  FIG. 11 ). 
     In  FIG. 17 , two separate information elements  3501 ,  3502  are used for the P-BWPs  601 ,  602  of the BSs  112 - 1 ,  112 - 2 . Because the P-BWPs are shared—i.e., use similar configuration parameters such as frequency position, bandwidth, transmission timing, and numerology in the non-limiting illustrated example—similar values for the configuration parameters are included in the information elements  3501 ,  3502 . Differently, in the example of  FIG. 18 , the configuration  3001  includes a single information element  3503  that includes the mapping  3510  to both BSs  112 - 1 ,  112 - 2 . 
     Although the invention has been shown and described with respect to certain preferred embodiments, equivalents and modifications will occur to others skilled in the art upon the reading and understanding of the specification. The present invention includes all such equivalents and modifications and is limited only by the scope of the appended claims. 
     For instance, various examples have been described in which a LS implements a LMF to facilitate positioning of a UE. The techniques described herein can also be used in connection with other implementations of the LS. 
     For further illustration, various examples have been described in connections with implementations of ANs by BSs of a cellular network, the techniques can also be applied to other types of communication systems. 
     Still further, while various examples have been described in connection with OTDOA or TDOA positioning, other kinds and types of positioning techniques using PRSs may benefit from the techniques described herein. For example, the techniques described herein can also be applied to other measurement method, such as signal strength measurements (e.g., Reference Signal Receive Power, RSRP; or Signal to Interference plus Noise Ratio, SINR).