WO2018200257A1

WO2018200257A1 - Positioning techniques in wireless devices

Info

Publication number: WO2018200257A1
Application number: PCT/US2018/027941
Authority: WO
Inventors: Bapineedu Chowdary GUMMADI; Hem AGNIHOTRI; Weihua Gao
Original assignee: Qualcomm Incorporated
Priority date: 2017-04-28
Filing date: 2018-04-17
Publication date: 2018-11-01

Abstract

Disclosed are user equipment (UE) and methods pertaining to one or more transceivers, configured to access assistance data that indicates positioning signal parameters that are associated with a first serving eNodeB (eNB), to which the UE is connected and a second serving eNB, to which the UE is simultaneously connected. Also, the first serving eNB is associated with a first channel condition. A processor is coupled to the one or more transceivers that are configured to determine that the first channel condition prevents an accurate time difference measurement associated with the first serving eNB. Then selecting for measurement, in response to this determination, the second serving eNB. And, in response to this selecting, measuring a time of arrival of a positioning signal corresponding to the selected eNB and including a memory coupled to the processor and configured to store data, instructions, or any combination thereof.

Description

POSITIONING TECHNIQUES IN WIRELESS DEVICES

INTRODUCTION

[0001] Aspects of this disclosure relate generally to wireless communication, and more particularly to improved positioning techniques in wireless devices and the like.

[0002] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, data, multimedia, and so on. Typical wireless communication systems are multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). 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, Orthogonal Frequency Division Multiple Access (OFDMA) systems, and others. These systems are often deployed in conformity with specifications such as Long-Term Evolution (LTE) provided by the Third Generation Partnership Project (3GPP), Ultra Mobile Broadband (UMB) and Evolution Data Optimized (EV-DO) provided by the Third Generation Partnership Project 2 (3GPP2), 802.11 provided by the Institute of Electrical and Electronics Engineers (IEEE), etc.

[0003] As technology advances, these wireless communication systems have increasingly optimized communications between, for example, an eNodeB (sometimes abbreviated as "eNB") and a user equipment (sometimes abbreviated as "UE"). Some techniques used to optimize these communications attempt to determine a position of a particular UE. The determined position is provided to a location server, which uses the UE's known position to improve mobility, increase data throughput, or conserve resources.

[0004] However, UE position determinations can sometimes be inaccurate or resource-intensive, which may limit the system's ability to improve mobility, increase data throughput, or conserve resources. Accordingly, improved positioning techniques may have significant benefits. SUMMARY

[0005] The following summary is an overview provided solely to aid in the description of various aspects of the disclosure and is provided solely for illustration of the aspects and not limitation thereof.

[0006] In accordance with aspects of the disclosure, a user equipment (UE) is disclosed. The UE may comprise one or more transceivers configured to access assistance data that indicates positioning signal parameters associated with at least a first serving eNodeB (eNB) to which the UE is connected and a second serving eNB to which the UE is simultaneously connected, the first serving eNB being associated with a first channel condition, a processor coupled to the one or more transceivers, and memory coupled to the processor and configured to store data, instructions, or a combination thereof. The processor may be configured to configured to determine that the first channel condition prevents an accurate time difference measurement associated with the first serving eNB, in response to the determining, select for measurement the second serving eNB, and in response to the selecting, measure a time of arrival of a positioning signal corresponding to the selected eNB.

[0007] In accordance with other aspects of the disclosure, a method is disclosed. The method may comprise accessing assistance data that indicates positioning signal parameters associated with at least a first serving eNodeB (eNB) to which a user equipment (UE) is connected and a second serving eNB to which the UE is simultaneously connected, the first serving eNB being associated with a first channel condition, determining that the first channel condition prevents an accurate time difference measurement associated with the first serving eNB, in response to the determination that the first channel condition prevents an accurate time difference measurement, selecting for measurement the second serving eNB, and in response to the selecting, measuring a time of arrival of a positioning signal corresponding to the selected eNB.

[0008] In accordance with yet other aspects of the disclosure, another UE is disclosed. The UE may comprise one or more transceivers configured to access assistance data that indicates positioning signal parameters associated with at least a first serving eNodeB (eNB) to which the UE is connected at a first frequency, a second serving eNB to which the UE is simultaneously connected at a second frequency, and one or more neighbor eNBs, a processor coupled to the one or more transceivers, and memory coupled to the processor and configured to store data, instructions, or a combination thereof. The processor may be configured to configured to determine that the one or more neighbor cells operate on the second frequency, in response to the determination that the one or more neighbor cells operate on the second frequency, select for measurement the second serving eNB, and in response to the selecting, measure a time of arrival of a positioning signal corresponding to the selected eNB.

[0009] In accordance with yet other aspects of the disclosure, another method is disclosed. The method may comprise accessing assistance data that indicates positioning signal parameters associated with at least a first serving eNodeB (eNB) to which the UE is connected at a first frequency, a second serving eNB to which the UE is simultaneously connected at a second frequency, and one or more neighbor eNBs, determining that the one or more neighbor cells operate on the second frequency, in response to the determination that the one or more neighbor cells operate on the second frequency, selecting for measurement the second serving eNB, and in response to the selecting, measuring a time of arrival of a positioning signal corresponding to the selected eNB.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings are presented to aid in the description of various aspects of the disclosure and are provided solely for illustration of the aspects and not limitation thereof.

[0011] FIG. 1 generally illustrates a wireless communication system in accordance with conventional techniques.

[0012] FIG. 2 generally illustrates a signal flow diagram for position determination in accordance with conventional techniques.

[0013] FIG. 3 generally illustrates a wireless communication system in accordance with aspects of the disclosure.

[0014] FIG. 4 generally illustrates a UE in accordance with aspects of the disclosure.

[0015] FIG. 5 generally illustrates a signal flow diagram for position determination in accordance with aspects of the disclosure. [0016] FIG. 6 generally illustrates a first method for selecting an eNB in accordance with the signal flow diagram of FIG. 5.

[0017] FIG. 7 generally illustrates a first method for selecting an eNB in accordance with the signal flow diagram of FIG. 6.

DETAILED DESCRIPTION

[0018] As noted above, UE position determinations can sometimes be inaccurate or resource-intensive, which may limit the system's ability to improve mobility, increase data throughput, or conserve resources. Newer wireless communication systems improve mobility by utilizing a technique known as 'dual connectivity'. If a UE is configured for dual connectivity, it may be capable of simultaneously camping on two eNBs rather than a single eNB. In accordance with aspects of the disclosure, these capabilities are further leveraged to improve position determinations.

[0019] For example, OTDOA (Observed Time Difference Of Arrival) is a UE- positioning feature introduced in Release 9 E-UTRA (LTE radio). To perform OTDOA, the UE uses PRS signals (where PRS stands for Positioning Reference Signaling) transmitted from, for example, a serving eNB and two neighbor eNBs. In particular, the UE performs a RSTD measurement (where RSTD stands for Reference Signal Time Difference) corresponding to each of the eNBs.

[0020] However, difficulties may arise when there is excessive interference between the UE and one or more of the eNBs. Moreover, configuration of multiple eNBs - which may not use the same frequency or frequencies - can result in excessive signaling overhead (for example, configuration of measurement gaps). In accordance with aspects of the disclosure, a dual-connectivity UE can mitigate some of these difficulties. As will be discussed in greater detail below, a dual-connectivity UE may communicate with a wider array of eNBs. By dynamically selecting one or more eNBs for measurement purposes based on one or more rules that improve mobility, increase data throughput, or conserve resources, the dual-connectivity UE can improve the accuracy and/or efficiency of the positioning determinations.

[0021] FIG. 1 generally illustrates a wireless communication network 100 in accordance with conventional techniques. The wireless communication network 100 includes a serving eNB 110, a UE 120, a first neighbor cell 130, a second neighbor cell 140, and a location server 150. The serving eNB 1 10 may be associated with an eNB coverage area 11 1, the first neighbor cell 130 may be associated with a first neighbor cell coverage area 131 , and the second neighbor cell 140 may be associated with a second neighbor cell coverage area 141. The UE 120 may receive PRS signals from each of the serving eNB 110, the first neighbor cell 130, and the second neighbor cell 140. For example, the UE 120 may receive a PRS signal 121 from the serving eNB 110, a PRS signal 123 from the first neighbor cell 130, and a 124 from the second neighbor cell 140.

[0022] As will be discussed in greater detail below (in the description of FIG. 2), the location server 150 may configure one or more of the constituents of the wireless communication network 100 to determine a position of the UE 120 using the PRS signal 121 , the PRS signal 123, and the PRS signal 124.

[0023] FIG. 2 generally illustrates a signal flow diagram for position determination in accordance with conventional techniques. In particular, FIG. 2 depicts positioning- related signaling between the serving eNB 1 10, the UE 120, and the location server 150. It will be understood that the first neighbor cell 130 and second neighbor cell 140, although not depicted in FIG. 2, may also participate in the positioning determination, as will be discussed in greater detail below.

[0024] At 230, the location server 150 may exchange eNB configuration data with the serving eNB 110. At 232, the serving eNB 110 may exchange eNB configuration data with the location server 150. In some implementations, the exchange may include an instruction from the location server 150 to generate and transmit the PRS signal 121 such that it has particular PRS signal characteristics and/or PRS signal timing. Additionally or alternatively, the exchange may include a notification from the serving eNB 1 10 to the location server 150 of the particular PRS signal characteristics and/or PRS signal timing used to generate and transmit the PRS signal 121.

[0025] At 240, the serving eNB 1 10 may generate and transmit the PRS signal 121. As noted above, the PRS signal 121 may have a particular PRS signal characteristics and/or PRS signal timing associated with the eNB configuration data exchanged at 230 and 232. Accordingly, the serving eNB 110 may generate the PRS signal 121 having the instructed characteristics and commence transmission of the PRS signal 121 in accordance with the instructed timing. [0026] Although not depicted in FIG. 2, the location server 150 may also exchange eNB configuration data with the first neighbor cell 130 and the second neighbor cell 140. This exchanging may be analogous in some respects to the exchanging 230 and the exchanging 232, but the content of the eNB configuration data may differ. For example, the PRS parameters transmitted to the first neighbor cell 130 and the second neighbor cell 140 may differ from one another and may further differ from the PRS parameters transmitted to the serving eNB 110.

[0027] The first neighbor cell 130 and the second neighbor cell 140 may generate and transmit the PRS signal 123 and the PRS signal 124, respectively. The generating and transmitting may be analogous in some respects to the generating and transmitting 240. However, since the content of the eNB configuration data may differ, the PRS signal 123 and the PRS signal 124 may differ as well. For example, the first neighbor cell 130 may generate the PRS signal 123 having different PRS signal characteristics relative to the PRS signal 121 and/or PRS signal 124. Additionally or alternatively, the first neighbor cell 130 may transmit the PRS signal 123 at a different PRS signal timing than the PRS signal 121 and/or PRS signal 124. Similarly, the second neighbor cell 140 may generate the PRS signal 124 having its own distinctive PRS signal characteristics and/or PRS signal timing.

[0028] At 250, the location server 150 transmits a measurement request to the UE 120. The measurement request may include, for example, assistance data and an instruction to perform RTSD measurements. The assistance data may indicate, for example, the particular PRS parameters of the PRS signal 121 transmitted by the serving eNB 110, the particular PRS parameters of the PRS signal 123 transmitted by the first neighbor cell 130, and the particular PRS parameters of the PRS signal 124 transmitted by the second neighbor cell 140. At 252, the UE 120 receives the measurement request.

[0029] At 270, the UE 120 may perform the requested measurement. For example, the UE 120 may receive each of the PRS signal 121, the PRS signal 123, and the PRS signal 124. Based on the PRS parameters provided in the assistance data received at 252, the UE 120 may be able to distinguish the PRS signal 121, the PRS signal 123, and the PRS signal 124 based on their respective PRS signal characteristics and/or PRS signal timing. [0030] The UE 120 may measure a respective time of arrival τ for each of the PRS signal 121, the PRS signal 123, and the PRS signal 124. The times of arrival x , xm, and xi₂₄ may indicate the respective times of flight associated with the PRS signal 121, the PRS signal 123, and the PRS signal 124. The UE 120 may select a reference time of arrival from among the three respective times of arrival, and may further calculate two observed Reference Signal Time Differences (RSTDs) relative to the reference time of arrival (for example, m - m and xm - xm)- Using these values, the UE 120 may be able to determine a position of the UE 120.

[0031] At 280, the UE 120 transmits the measurement result to the location server 150. As noted above, the measurement result may include two observed RSTDs. Using these values, the location server 150 may be able to determine a position of the UE 120.

[0032] FIG. 3 generally illustrates a wireless communication network 300 in accordance with aspects of the disclosure. The wireless communication network 300 may include a UE 320 that is analogous in some respects to the UE 120 depicted in FIG. 1. However, unlike the UE 120, the UE 320 may be configured for dual connectivity.

[0033] As noted above, a UE configured for dual connectivity may be capable of simultaneously camping on two eNBs rather than a single eNB. The two eNBs may be known as a 'master' eNB and a 'secondary' eNB. In an example of dual-connectivity operations, the UE 320 may exchange control signaling with either or both of the master eNB and the secondary eNB, while simultaneously receiving data on the downlink from both the master eNB and the secondary eNB.

[0034] Accordingly, the wireless communication network 300 may include a master eNB 310, a first master neighbor cell 330, and a second master neighbor cell 340. The master eNB 310, the first master neighbor cell 330, and the second master neighbor cell 340 may be referred to collectively as the master cell group (MCG).

[0035] The master eNB 310, the first master neighbor cell 330, and the second master neighbor cell 340 may be analogous in some respects to the serving eNB 110, the first neighbor cell 130, and the second neighbor cell 140 depicted in FIG. 1. For example, the master eNB 310 may be associated with a master eNB coverage area 311 , the first master neighbor cell 330 may be associated with a first master neighbor cell coverage area 331, and the second master neighbor cell 340 may be associated with a second master neighbor cell coverage area 341. Moreover, the UE 320 may receive a PRS signal 321 analogous to the PRS signal 121, a PRS signal 323 analogous to the PRS signal 123, and a PRS signal 324 analogous to the PRS signal 124.

[0036] The wireless communication network 300 may further include a secondary eNB 360, a first secondary neighbor cell 370, and a second secondary neighbor cell 380. The secondary eNB 360, the first secondary neighbor cell 370, and the second secondary neighbor cell 380 may be referred to collectively as a secondary cell group (SCG).

[0037] The secondary eNB 360 may be associated with a secondary eNB coverage area 361, the first secondary neighbor cell 370 may be associated with a first secondary neighbor cell coverage area 371 , and the second secondary neighbor cell 380 may be associated with a second secondary neighbor cell coverage area 381. Unlike the UE 120, which is not configured for dual connectivity, the UE 320 may be capable of simultaneously camping on both the master eNB 310 and the secondary eNB 360. To camp on, for example, the master eNB 310, the UE 320 may identify the master eNB 310 as a suitable cell for communications and may attach to the master eNB 310 using an attach procedure. The UE 320 may further identify secondary eNB 360 as a suitable cell for communications and attach to the secondary eNB 360 using an attach procedure. The UE 320 may perform the attach procedure with respect to the secondary eNB 360 while it is already camped on the master eNB 310.

[0038] As will be discussed in greater detail below, the UE 320 may be configured to utilize its dual-connectivity capabilities to improve the accuracy of a positioning determination and/or the efficiency of the wireless communication network 300.

[0039] FIG. 4 generally illustrates a detail of the UE 320 depicted in FIG. 3. The UE 320 may include a processing system 410, memory 420, a transceiver 430, and an interconnection 440. The UE 320 may include other suitable components, for example, one or more batteries, one or more interfaces for user input/output, etc (not shown).

[0040] Unless otherwise noted, the term "UE" is not intended to be specific or limited to any particular Radio Access Technology (RAT). As used herein, a UE may be any wireless communication device allowing a user to communicate over a communications network (e.g., a mobile phone, router, personal computer, server, entertainment device, Internet of Things (IOT) / Internet of Everything (IOE) capable device, in-vehicle communication device, etc.), and may be alternatively referred to in different RAT environments as a User Device (UD), a Mobile Station (MS), a Subscriber Station (STA), an Access Terminal (AT), etc. Similarly, an eNB may operate according to one or several RATs in communicating with UEs depending on the network in which the eNB is deployed, and may be alternatively referred to as a Base Station (BS), a Network Node, a NodeB, an Access Point (AP), etc.

[0041] The memory 420 of the UE 320 may be configured to store data, instructions, or any combination thereof. The processing system 410 of the UE 320 may include one or more processors configured to operate the UE 320 based on the data or instructions stored in the memory 420. The data or instructions may include code for performing any function performed by the UE 320 that is described in the present disclosure. The data or instructions may be transmitted to the processing system 410 via the interconnection 440. The processing system 410 may be implemented as a collection of elements, each element configured to perform a different function. For example, the processing system 410 may include a channel condition determiner for determining that a channel condition (for example, a first channel condition associated with a first serving eNB) may prevent an accurate time difference measurement. The processing system 410 may further include a selector for selecting for measurement a second serving eNB in response to the determining of the channel condition. The processing system 410 may further include a measurer configured to measure a time of arrival of a positioning signal corresponding to the selected eNB in response to the selecting of the second serving eNB. As another example, the processing system 410 may include a frequency determiner configured to determine that the one or more neighbor cells operate on a frequency (for example, a second frequency). The processing system 410 may further include a selector for selecting for measurement a second serving eNB in response to the frequency determining. The processing system 410 may further include a measurer configured to measure a time of arrival of a positioning signal corresponding to the selected eNB in response to the selecting of the second serving eNB.

[0042] The transceiver 430 may be configured to transmit and/or receive wireless signals. The transceiver 430 may encode signals for transmission in accordance with one or more RATs or decode signals received in accordance with one or more RATs. The transceiver 430 may include one transceiver configured to perform all of the transmitting and receiving associated with the UE 320. Alternatively, the transceiver 430 may include a plurality of transceivers. In some implementations, the plurality of transceivers may be configured to operate in accordance with different respective RATs.

[0043] In some implementations, the transceiver 430 may include a dedicated processing system and memory configured to perform transceiver-specific operations, and may perform all of the functions, or any combination thereof, described in the present disclosure. Accordingly, a function that is performed autonomously by the transceiver 430 may be considered to be "performed by the transceiver 430". Additionally or alternatively, the transceiver 430 may be configured to operate in accordance with commands that are received from the processing system 410 and/or memory 420. The transceiver 430 may perform all of the functions, or any combination thereof, described in the present disclosure in response to commands received from the processing system 410 and/or memory 420. A function that is performed by the transceiver in response to received commands from the processing system 410 and/or memory 420 may also be considered to be "performed by the transceiver 340". Thus, a disclosure that the transceiver 430 is configured to perform a certain operation may be treated as an implicit disclosure that the processing system 410 is configured to command the transceiver 430 to perform the particular operation and/or that the memory 420 is configured to store the command.

[0044] FIG. 5 generally illustrates a signal flow diagram for position determination in accordance with aspects of the disclosure. In particular, FIG. 5 depicts positioning- related signaling between the master eNB 310, the UE 320, the location server 350, and the secondary eNB 360. It will be understood that the first master neighbor cell 330, the second master neighbor cell 340, the first secondary neighbor cell 370, and the second secondary neighbor cell 380, although not depicted in FIG. 5, may also participate in the positioning determination, as will be discussed in greater detail below.

[0045] At 510, the UE 320 transmits UE capability information to the location server 350. At 512, the location server 350 receives the UE capability information. The transmitting 510 may take the form of a "LPP Provide Capabilities" message (as specified in, for example, 3GPP Technical Specification 36.355 vlO.0, where LPP stands for LTE Positioning Protocol). The transmitting 510 may be responsive to receipt of a "LPP Request Capabilities" message from the location server 350 (as specified in, for example, 3GPP Technical Specification 36.355 vl O.O).

[0046] The transmitting 510 may be performed, for example, by the transceiver 430 depicted in FIG. 4. Accordingly, the transceiver 430 may be considered as means for transmitting UE capability information. The receiving 512 may be performed, for example, by a transceiver or data port associated with the location server 350. Accordingly, the transceiver or data port associated with the location server 350 may be considered as means for receiving UE capability information.

[0047] In accordance with aspects of the disclosure, the UE capability information may include a band combination list. The band combination list may include one or more frequencies on which the UE 320 is configured to operate. For example, the UE 320 may be camped on the master eNB 310 using first frequency fi, and the UE 320 may simultaneously be camped on the secondary eNB 360 using second frequency Accordingly, the band combination list may include the master eNB 310 having the first frequency fi and the secondary eNB 360 having the second frequency The band combination list may be configured to indicate to the location server 350 that the UE 320 is capable of dual connectivity.

[0048] At 520, the location server 350 optionally determines that the UE is a dual- connectivity UE. The determining 520 may be based on the UE capability information received at 512. For example, the determining 520 may be based on a band combination list included in the UE capability information received at 512. In some implementations, only dual-connectivity UEs include the band combination list in the UE capability information transmitted at 510. By contrast, legacy devices not configured for dual- connectivity may transmit UE capability information that does not include a band combination list. Accordingly, the location server 350 may determine that the UE 320 is a dual-connectivity UE by identifying a band combination list in the UE capability information received at 520. In other implementations, the UE capability information may include a flag that explicitly indicates to the location server 350 that the UE 320 is a dual-connectivity UE.

[0049] The determining 520 may be performed, for example, by a processing system included in the location server 350. Accordingly, the processing system associated with the location server 350 may be considered as means for determining that the UE is a dual-connectivity UE.

[0050] At 530, the location server 350 may exchange eNB configuration data with the master eNB 310 and the secondary eNB 360. At 532, the master eNB 310 may exchange eNB configuration data with the location server 350. At 534, the secondary eNB 360 may exchange eNB configuration data with the location server 350. In some implementations, the exchange may include an instruction from the location server 350 to the master eNB 310 instructing the master eNB 310 to generate and transmit the PRS signal 321 with particular PRS parameters. Similarly, the exchange may include an instruction from the location server 350 to the secondary eNB 360 instructing the secondary eNB 360 to generate and transmit the PRS signal 326 with particular PRS parameters. Additionally or alternatively, the exchange may include notifications from the master eNB 310 and/or the secondary eNB 360 to the location server 350 of the particular PRS parameters used to generate and transmit the PRS signal 321 and/or secondary signaling 326, respectively.

[0051] The exchanging 530 may be performed, for example, by a transceiver or data port included in the location server 350. Accordingly, the transceiver or data port associated with the location server 350 may be considered as means for exchanging eNB configuration data. The exchanging 532 may be performed, for example, by a transceiver or data port included in the master eNB 310. Accordingly, the transceiver or data port associated with the master eNB 310 may be considered as means for exchanging eNB configuration data. The exchanging 534 may be performed, for example, by a transceiver or data port included in the secondary eNB 360. Accordingly, the transceiver or data port associated with the secondary eNB 360 may be considered as means for exchanging eNB configuration data.

[0052] At 542, the master eNB 310 may generate and transmit the PRS signal 321. At 544, the secondary eNB 360 may generate and transmit the PRS signal 326. As noted above, the PRS signal 321 may have particular PRS signal characteristics and/or PRS signal timing associated with the eNB configuration data exchanged at 530 and 532. Similarly, the PRS signal 326 may have particular PRS signal characteristics and/or PRS signal timing associated with the eNB configuration data exchanged at 530 and 534. Accordingly, the master eNB 310 may generate the PRS signal 321 having the particular PRS signal characteristics and commence transmission of the PRS signal 321 in accordance with the particular PRS signal timing. Additionally or alternatively, the secondary eNB 360 may generate the PRS signal 326 having the particular PRS signal characteristics and commence transmission of the PRS signal 326 in accordance with the particular PRS signal timing.

[0053] The generating and transmitting 542 may be performed by a transceiver, a data port, a processing system, and/or memory included in the master eNB 310. For example, the generating may be performed by the processing system and/or memory associated with the master eNB 310 and the transmitting may be performed by the transceiver and/or data port associated with the master eNB 310. Accordingly, the transceiver, data port, processing system, and/or memory associated with the master eNB 310 may be considered as means for generating and transmitting a PRS signal. The generating and transmitting 544 may be performed by a transceiver, a data port, a processing system, and/or memory associated with the secondary eNB 360. For example, the generating may be performed by the processing system and/or memory associated with the secondary eNB 360 and the transmitting may be performed by the transceiver and/or data port associated with the secondary eNB 360. Accordingly, the transceiver, data port, processing system, and/or memory associated with the secondary eNB 360 may be considered as means for generating and transmitting a PRS signal.

[0054] Although not depicted in FIG. 5, the location server 350 may also exchange eNB configuration data with the first master neighbor cell 330, the second master neighbor cell 340, the first secondary neighbor cell 370, and the second secondary neighbor cell 380. This exchanging may be analogous in some respects to the exchanging 530, the exchanging 532, and/or the exchanging 534, but the content of the eNB configuration data may differ. For example, the PRS parameters transmitted to the first master neighbor cell 330, the second master neighbor cell 340, the first secondary neighbor cell 370, and the second secondary neighbor cell 380 may differ from each other and may further differ from the PRS parameters transmitted to the master eNB 310 and the secondary eNB 360.

[0055] The first master neighbor cell 330 and the second master neighbor cell 340 may generate and transmit the PRS signal 323 and the PRS signal 324, respectively. The generating and transmitting may be analogous in some respects to the generating and transmitting 542 and/or the generating and transmitting 544. However, since the content of the eNB configuration data may differ, the PRS signal 323 and the PRS signal 324 may differ as well. For example, the first master neighbor cell 330 may generate the PRS signal 323 having different PRS signal characteristics relative to the PRS signal 321 and/or PRS signal 324. Additionally or alternatively, the first master neighbor cell 330 may transmit the PRS signal 323 at a different PRS signal timing than the PRS signal 321 and/or PRS signal 324. Similarly, the second master neighbor cell 340 may generate the PRS signal 324 having its own distinctive PRS signal characteristics and/or PRS signal timing.

[0056] At 550, the location server 350 transmits a measurement request to the UE 320. The measurement request may include, for example, assistance data and an instruction to perform RTSD measurements. The assistance data may indicate, for example, the particular PRS parameters of the PRS signals 321, 323, 324, 326, 327, and 328. At 552, the UE 320 receives the measurement request.

[0057] The transmitting 550 may be performed, for example, by a transceiver or data port included in the location server 350. Accordingly, the transceiver or data port associated with the location server 350 may be considered as means for transmitting a measurement request.

[0058] At 560, the UE 320 selects one or more eNBs for measurement, as will be discussed in greater detail below by reference to FIGS. 6 - 7. Returning briefly to FIG. 1, it will be understood that in accordance with conventional techniques, it is necessary for the UE 120 to receive each of the PRS signals 121, 123, 124 and determine a time of arrival τ for each. However, it will be understood that in accordance with the present disclosure, the UE 320, configured for dual connectivity, has six different PRS signals 321, 323, 324, 326, 327, 328 from which to choose. Accordingly, the UE 320 may be configured to select one or more PRS signals that will best enable the wireless communication network 300 to improve mobility, total throughput, or efficiency. The selecting 560 may be performed in accordance with any aspect of the present disclosure. As illustrative examples, a first detail of the selecting 560 depicted in FIG. 5 is depicted in FIG. 6, and a second detail of the selecting 560 depicted in FIG. 5 is depicted in FIG. 7. [0059] The selecting 560 may be performed, for example, by the processing system 410 and/or memory 420 depicted in FIG. 4. Accordingly, the processing system 410 and/or memory 420 may be considered as means for selecting one or more eNBs for measurement.

[0060] At 570, the UE 320 may perform the requested measurement. For example, the UE 320 may select the first master neighbor cell 330, the second master neighbor cell 340, and the secondary eNB 360 for measurements. Based on the PRS parameters provided in the assistance data received at 552, the UE 320 may be able to distinguish between the received PRS signals 321 , 323, 324, 326, 327, 328 based on their respective PRS signal characteristics and/or PRS signal timing. Accordingly, the UE 320 may isolate the PRS signals 323, 324, 326 and determine a respective time of arrival τ for each.

[0061] The times of arrival x₃₂3, 1324, 1326 may indicate the respective times of flight associated with the PRS signal 323, the PRS signal 324, and the PRS signal 326. The UE 320 may select a reference time of arrival from among the three respective times of arrival, and may further calculate two observed Reference Signal Time Differences (RSTDs) relative to the reference time of arrival (for example, 1326 - 1323 and 1324 - 1323). Using these values, the UE 320 may be able to determine a position of the UE 320.

[0062] The performing 570 may be performed, for example, by the processing system 410, the memory 420, and/or the transceiver 430 depicted in FIG. 4. Accordingly, the processing system 410, the memory 420, and/or the transceiver 430 may be considered as means for performing the requested measurement. The performing 570 may be considered a two-part process in which the transceiver 430 receives the PRS signals and the processing system 410 and/or memory 420 isolate the PRS signals from the selected eNBs, determines a time of arrival x for each, and calculates two observed RSTDs based on the times of arrival x. accordingly, the transceiver 430 may be considered as means for receiving a PRS signal and the processing system 410 and/or memory 420 may be considered as means for isolating a PRS signal from a selected eNB, means for determining a time of arrival for each isolated PRS signal, and/or means for calculating an RSTD based on the determined times of arrival. [0063] At 580, the UE 320 transmits the measurement result to the location server 350. At 582, the location server 350 receives the measurement result transmitted at 580.

[0064] The transmitting 580 may be performed, for example, by the transceiver 430 depicted in FIG. 4. Accordingly, the transceiver 430 may be considered as means for transmitting a measurement result. The receiving 582 may be performed, for example, by a transceiver or data port included in the location server 350. Accordingly, the transceiver or data port associated with the location server 350 may be considered as means for receiving a measurement result.

[0065] As noted above, the measurement result may include two observed RSTDs. Using these values, the location server 350 may be able to determine a position of the UE 320.

[0066] As discussed previously, the wireless communication network 300 may be configured to improve mobility, total throughput, or efficiency based on knowledge of the position of the UE 320. Accordingly, the location server 350 may provide the position data to the wireless communication network 300.

[0067] Turning now to the details of the selecting 560 depicted in FIGS. 6 - 7, it will be understood that different circumstances provide different opportunities for optimal positioning determination.

[0068] FIG. 6 generally illustrates a first detail of the selecting 560A. In the selecting 560A depicted in FIG. 6, the wireless communication network 300 confronts a circumstance where a channel condition within the wireless communication network 300 results in noisy communications between the UE 320 and an eNB, for example, the master eNB 310. If, in this example, the channel condition is poor, then the PRS signal 321 may be noisy, resulting in an inaccurate position determination.

[0069] Because the UE 320 is capable of dual connectivity, as noted above, the UE 320 may not have to rely on the PRS signal 321 to make the position determination. For example, the UE 320 may select some other eNB for measurement, for example, the secondary eNB 360. Accordingly, the UE 320 may select to use PRS signal 326 rather than the PRS signal 321 to make the position determination. By contrast, the UE 120 depicted in FIG. 1, which is incapable of dual connectivity, does not have the opportunity to select the secondary eNB 360 for measurement rather than the master eNB 310. [0070] At 610, the UE 320 determines a channel condition associated with the master eNB 310. The channel condition may be represented as a signal-to-noise ratio (SNR), a reference signal received power (RSRP), a reference signal strength indication (RSSI), a signal-to-interference-plus-noise ratio (SINR), a carrier-to-noise ratio (CNR), an energy per bit to noise density ratio (Et/No), any other suitable measurement, or any combination thereof.

[0071] The determining 610 may be performed, for example, by the transceiver 430 depicted in FIG. 4. Accordingly, the transceiver 430 may be considered as a means for determining a channel condition.

[0072] At 620, the UE 320 determines if the channel condition determined at 610 meets criteria that correspond to an accurate time difference measurement. For example, the UE 320 may compare the SNR associated with the PRS signal 321 to a predetermined threshold SNR that represents the dividing line between a clear channel and a noisy channel. In particular, the UE 320 may determine that if the measured SNR exceeds the threshold SNR, then the criteria are met and the PRS signal 321 enables an accurate time difference measurement. Altematively, the UE 320 may determine that if the measured SNR does not exceed the threshold SNR, then the criteria are not met and the channel condition prevents an accurate time difference measurement.

[0073] As another example, the UE 320 may compare the SNR associated with the PRS signal 321 (SNR₃₂i) to an SNR associated with the PRS signal 326 (SNR₃₂₆). In particular, the UE 320 may determine that if the measured SNR₃₂i exceeds the SNR₃₂₆, then the criteria are met. It will be understood that analogous thresholds may be set and analogous comparisons may be performed if the channel condition is represented as, for example, SINR, CNR, Et,/N₀ or some other suitable measurement.

[0074] The determining 620 may be performed, for example, by the processing system 410 and/or the memory 420 depicted in FIG. 4. Accordingly, the processing system 410 and/or the memory 420 may be considered as means for determining if the channel condition meets criteria.

[0075] If at 620, the UE 320 determines that the channel condition meets criteria ('yes' at 620), then the selecting 560A proceeds to 630. If at 620, the UE 320 determines that the channel condition does not meet criteria ('no' at 620), then the selecting 560A proceeds to 640. [0076] At 630, the UE 320 selects the master eNB 310 for measurement. As will be understood from the foregoing, the selecting 630 may be responsive to a determination at 620 that a channel condition associated with the master eNB 310 meets criteria.

[0077] At 640, the UE 320 selects the secondary eNB 360 for measurement. As will be understood from the foregoing, the selecting 640 may be responsive to a determination at 620 that a channel condition associated with the master eNB 310 does not meet criteria.

[0078] The selecting 630 and/or the selecting 640 may be performed, for example, by the processing system 410 and/or the memory 420 depicted in FIG. 4. Accordingly, the processing system 410 and/or the memory 420 may be considered as means for selecting the master eNB 310 for measurement and/or means for selecting the secondary eNB 360 for measurement.

[0079] Although the foregoing illustration details selection between the master eNB 310 and the secondary eNB 360, it will be understood that the selecting 560A may be extended in any suitable manner. For example, instead of selecting either the master eNB 310 or the secondary eNB 360, the selecting 560A may use a measured channel condition to choose the three best eNBs (i.e., the three least noisy eNBs) from among the six different eNBs in the wireless communication network 300. For example, if the SNRs respectively associated with the PRS signal 321, the PRS signal 327, and the PRS signal 328 are superior to the SNRs respectively associated with the PRS signal 323, the PRS signal 324, and the PRS signal 326, then the selecting 560A may select the PRS signals associated with the superior SNRs.

[0080] FIG. 7 generally illustrates a second detail of the selecting 560B. In the selecting 560B depicted in FIG. 7, the wireless communication network 300 confronts a circumstance where one or more of the six eNBs transmits a PRS signal on two or more different frequencies. In this case, an inter-frequency measurement may be necessary. Accordingly, the wireless communication network 300 must configure a measurement gap. When a measurement gap is defined by the wireless communication network 300 (for example, by the master eNB 310), it may require that all UEs in the master eNB coverage area 31 1 maintain radio silence for the duration of the measurement gap. Accordingly, a measurement gap reduced total throughput of the wireless communication network 300. Moreover, because the definition of the measurement gap must be communicated within the wireless communication network 300, the amount of overhead control signaling is increased.

[0081] The UE 320 may not have to rely on PRS signals associated with different frequencies to make the position determination. For example, if three of the six eNBs depicted in FIG. 3 have a common frequency, then the UE 320 may select these three eNBs for measurement. In this scenario, inter-frequency measurement can be avoided, thereby increasing the throughput of the wireless communication network 300 and reducing the overhead control signaling.

[0082] For the UE 320, which is configured for dual connectivity, the UE 320 may select for measurement from any of the six eNBs depicted in FIG. 3 that happen to share the common frequency. For a UE that is not configured for dual-connectivity, but is otherwise analogous to the UE 320, the UE may determine that a plurality of eNBs associated with a single cell group (for example, the MCG or the SCG) share the common frequency and request a handover to the secondary eNB 360. The handover request may take the form of an explicit request transmitted to the master eNB 310, or a false measurement report provided to the master eNB 310 that is intended to trigger a handoff command.

[0083] At 710, the UE 320 identifies a common frequency associated with one or more eNBs. For example, consider a scenario where the master eNB 310 transmits the PRS signal 321 on a first frequency fi, each of the first master neighbor cell 330, the second master neighbor cell 340, and the secondary eNB 360 transmit the respective PRS signals 323, 324, 326, on a second frequency and the first secondary neighbor cell 370 and second secondary neighbor cell 380 transmit the respective PRS signals 327, 328 on a third frequency fs. The UE 320 may identify at 710 the second frequency as being common to the first master neighbor cell 330, the second master neighbor cell 340, and the secondary eNB 360.

[0084] The identifying 710 may be performed, for example, by the processing system 410 and/or memory 420 depicted in FIG. 4. Accordingly, the processing system 410 and/or memory 420 may be considered as a means for identifying a common frequency associated with one or more eNBs.

[0085] At 720, the UE 320 determines if a particular eNB is transmitting on the common frequency identified at 710. To return to the previous example (in which the PRS signals 323, 324, 326 are each transmitted on the second frequency fi), the UE 320 may determine if, for example, the master eNB 310 transmits on the second frequency

[0086] The determining 720 may be performed, for example, by the processing system 410 and/or the memory 420 depicted in FIG. 4. Accordingly, the processing system 410 and/or the memory 420 may be considered as means for determining if an eNB is transmitting on a common frequency.

[0087] If at 720, the UE 320 determines that the eNB is transmitting on the common frequency ('yes' at 720), then the selecting 560B proceeds to 730. If at 720, the UE 320 determines that the eNB is not transmitting on the common frequency ('no' at 720), then the selecting 560B proceeds to 740.

[0088] At 730, the UE 320 selects the particular eNB for measurement. As will be understood from the foregoing, the selecting 730 may be responsive to a determination at 720 that the particular eNB is transmitting on the common frequency identified at 710.

[0089] At 740, the UE 320 does not select the particular eNB for measurement. As will be understood from the foregoing, the selecting 740 may be responsive to a determination at 720 that the particular eNB is not transmitting on the common frequency identified at 710.

[0090] The selecting 730 and/or the selecting 740 may be performed, for example, by the processing system 410 and/or the memory 420 depicted in FIG. 4. Accordingly, the processing system 410 and/or the memory 420 may be considered as means for selecting an eNB for measurement and/or means for not selecting an eNB for measurement.

[0091] In accordance with the selecting 560B, the determining 720 and the selecting 730 or 740 may be repeated for a plurality of eNBs. In some implementations, the plurality of eNBs may include each of the six eNBs depicted in FIG. 3. To return to the previous example (in which the PRS signals 323, 324, 326 are each transmitted on the second frequency fi), the UE 320 may determine if the master eNB 310 transmits on the second frequency In response to a determination that the master eNB 310 does not transmit on the second frequency, the UE 320 may not select the master eNB 310 for measurement. The UE 320 may further determine if the first master neighbor cell 330 (and subsequently, the second master neighbor cell 340 and the secondary eNB 360) transmit on the second frequency. In response to a determination that the first master neighbor cell 330 (and subsequently, the second master neighbor cell 340 and the secondary eNB 360) does transmit on the second frequency, the UE 320 may select the first master neighbor cell 330 (and subsequently, the second master neighbor cell 340 and the secondary eNB 360) for measurement. The UE 320 may further determine that the first secondary neighbor cell 370 and the second secondary neighbor cell 380 do not transmit on the second frequency and exclude the first secondary neighbor cell 370 and the second secondary neighbor cell 380 from selection along with the master eNB 310.

[0092] Although FIGS. 6 - 7 depict different selection methods 560A and 560B, it will be understood that other selection methods are possible in accordance with any aspect of the present disclosure. Moreover, the selection method 560A, selection method 560B, and/or other suitable selection method may be hybridized so as to make more accurate position determinations and to reduce a number of inter-frequency measurements. For example, if four eNBs each transmit on a common frequency, then the selecting 560 may include selection of three of the four eNBs on the basis of channel condition.

[0093] The functionality described in the present disclosure may be implemented in various ways consistent with the teachings herein. In some designs, the functionality described in the present disclosure may be implemented as one or more electrical components. In some designs, the functionality described in the present disclosure may be implemented as a processing system including one or more processor components. In some designs, the functionality described in the present disclosure may be implemented using, for example, at least a portion of one or more integrated circuits (e.g., an ASIC). As discussed herein, an integrated circuit may include a processor, software, other related components, or any combination thereof. Thus, the different functionalities may be implemented, for example, as different subsets of an integrated circuit, as different subsets of a set of software modules, or a combination thereof. Also, it will be appreciated that a given subset (e.g., of an integrated circuit and/or of a set of software modules) may provide at least a portion of the functionality for more than one function.

[0094] The terminology used herein is for the purpose of describing particular embodiments only and not to limit any embodiments disclosed herein. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising", "includes" and/or "including", when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. Similarly, the phrase "based on" as used herein does not necessarily preclude influence of other factors and should be interpreted in all cases as "based at least in part on" rather than, for example, "based solely on".

[0095] It will be understood that terms such as "top" and "bottom", "left" and "right", "vertical" and "horizontal", etc., are relative terms used strictly in relation to one another, and do not express or imply any relation with respect to gravity, a manufacturing device used to manufacture the components described herein, or to some other device to which the components described herein are coupled, mounted, etc.

[0096] It should be understood that any reference to an element herein using a designation such as "first," "second," and so forth does not generally limit the quantity, order, or priority of those elements. Rather, these designations may be used herein as a convenient method of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not imply that there are only two elements and further does not imply that the first element must precede the second element in some manner. Also, unless stated otherwise a set of elements may comprise one or more elements. In addition, terminology of the form "at least one of A, B, or C" or "one or more of A, B, or C" or "at least one of the group consisting of A, B, and C" used in the description or the claims means "A or B or C or any combination of these elements."

[0097] In view of the descriptions and explanations above, one skilled in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.

[0098] Accordingly, it will be appreciated, for example, that an apparatus or any component of an apparatus may be configured to (or made operable to or adapted to) provide functionality as taught herein. This may be achieved, for example: by manufacturing (e.g., fabricating) the apparatus or component so that it will provide the functionality; by programming the apparatus or component so that it will provide the functionality; or through the use of some other suitable implementation technique. As one example, an integrated circuit may be fabricated to provide the requisite functionality. As another example, an integrated circuit may be fabricated to support the requisite functionality and then configured (e.g., via programming) to provide the requisite functionality. As yet another example, a processor circuit may execute code to provide the requisite functionality.

[0099] Moreover, the methods, sequences, and/or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in Random-Access Memory (RAM), flash memory, Read-only Memory (ROM), Erasable Programmable Read-only Memory (EPROM), Electrically Erasable Programmable Read-only Memory (EEPROM), registers, hard disk, a removable disk, a CD-ROM, or any other form of non-transitory storage medium known in the art. As used herein the term "non-transitory" does not exclude any physical storage medium or memory and particularly does not exclude dynamic memory (e.g., RAM) but rather excludes only the interpretation that the medium can be construed as a transitory propagating signal. An example storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor (e.g., cache memory).

[00100] While the foregoing disclosure shows various illustrative aspects, it should be noted that various changes and modifications may be made to the illustrated examples without departing from the scope defined by the appended claims. The present disclosure is not intended to be limited to the specifically illustrated examples alone. For example, unless otherwise noted, the functions, steps, and/or actions of the method claims in accordance with the aspects of the disclosure described herein need not be performed in any particular order. Furthermore, although certain aspects may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.

Claims

CLAIMS WHAT IS CLAIMED IS:

1. A user equipment (UE), comprising:

one or more transceivers configured to access assistance data that indicates positioning signal parameters associated with at least a first serving eNodeB (eNB) to which the UE is connected and a second serving eNB to which the UE is simultaneously connected, the first serving eNB being associated with a first channel condition;

a processor coupled to the one or more transceivers configured to:

determine that the first channel condition prevents an accurate time difference measurement associated with the first serving eNB; in response to the determining, select for measurement the second serving eNB; and

in response to the selecting, measure a time of arrival of a positioning signal corresponding to the selected eNB; and memory coupled to the processor and configured to store data, instructions, or a combination thereof.

2. The UE of claim 1, wherein to determine that the first channel condition prevents the accurate time difference measurement associated with the first serving eNB, the processor is further configured to:

determine that a signal-to-interference-and-noise ratio (SINR) between the first serving eNB and the UE does not exceed a threshold SINR value; or

determine that a reference signal received power (RSRP) associated with the first serving eNB and the UE does not exceed a threshold RSRP value;

determine that a reference signal strength indication (RSSI) associated with the first serving eNB does not exceed a threshold RSSI value; or

any combination thereof.

3. The UE of claim 1, further comprising receiving a request for Reference Signal Time Difference (RSTD) measurements, wherein the positioning signal parameters are Positioning Reference Signaling (PRS) parameters.

4. The UE of claim 1, wherein the UE is configured for dual connectivity, the first serving eNB is a Master eNodeB (MeNB) associated with a Master Cell Group (MCG) and the second serving eNB is a Secondary eNodeB (SeNB) associated with a Secondary Cell Group (SCG).

5. The UE of claim 4, wherein the MCG includes the MeNB and at least one neighbor eNB, the processor being further configured to:

measure a time of arrival of a positioning signal corresponding to the at least one neighbor eNB; and

determine a position of the UE based on the measured times of arrival of the positioning signal corresponding to the selected eNB and the positioning signal corresponding to the at least one neighbor eNB.

6. The UE of claim 1, wherein the one or more transceivers are further configured to:

transmit UE capability information to a server, wherein the UE capability information includes a dual connectivity band combination that indicates a band combination supported by the UE.

7. The UE of claim 1, wherein:

the processor is further configured to calculate a difference between the time of arrival of the positioning signal corresponding to the selected eNB and another time of arrival to generate a Reference Signal Time Difference (RSTD) measurement; and

the one or more transceivers are further configured to transmit the RSTD measurement to a location server.

8. The UE of claim 1, wherein the UE is further configured to camp on the first serving eNB and the second serving eNB simultaneously, wherein: to camp on the first serving eNB, the processor is further configured to attach to the first serving eNB using a first attach procedure; and

to camp on the second serving eNB simultaneously, the processor is further configured to attach to the second serving eNB using a second attach procedure while attached to the first serving eNB.

9. A method, comprising:

accessing assistance data that indicates positioning signal parameters associated with at least a first serving eNodeB (eNB) to which a user equipment (UE) is connected and a second serving eNB to which the UE is simultaneously connected, the first serving eNB being associated with a first channel condition;

determining that the first channel condition prevents an accurate time difference measurement associated with the first serving eNB;

in response to the determination that the first channel condition prevents an accurate time difference measurement, selecting for measurement the second serving eNB; and

in response to the selecting, measuring a time of arrival of a positioning signal corresponding to the selected eNB.

10. The method of claim 9, wherein determining that the first channel condition prevents the accurate time difference measurement associated with the first serving eNB comprises:

determining that a signal-to-interference-and-noise ratio (SINR) between the first serving eNB and the UE does not exceed a threshold SINR value; or

determining that a reference signal received power (RSRP) associated with the first serving eNB and the UE does not exceed a threshold RSRP value;

determining that a reference signal strength indication (RSSI) associated with the first serving eNB does not exceed a threshold RSSI value; or

any combination thereof.

11. The method of claim 9, further comprising receiving a request for Reference Signal Time Difference (RSTD) measurements, wherein the positioning signal parameters are Positioning Reference Signaling (PRS) parameters.

12. The method of claim 9, wherein the UE is configured for dual connectivity, the first serving eNB is a Master eNodeB (MeNB) associated with a Master Cell Group (MCG) and the second serving eNB is a Secondary eNodeB (SeNB) associated with a Secondary Cell Group (SCG).

13. The method of claim 12, wherein the MCG includes the MeNB and at least one neighbor eNB, the method further comprising:

measuring a time of arrival of a positioning signal corresponding to the at least one neighbor eNB; and

determining a position of the UE based on the measured times of arrival of the positioning signal corresponding to the selected eNB and the positioning signal corresponding to the at least one neighbor eNB.

14. The method of claim 9, further comprising:

transmitting UE capability information to a server, wherein the UE capability information includes a dual connectivity band combination that indicates a band combination supported by the UE.

15. The method of claim 9, further comprising:

calculating a difference between the time of arrival of the positioning signal corresponding to the selected eNB and another time of arrival to generate a Reference Signal Time Difference (RSTD) measurement; and

transmitting the RSTD measurement to a location server.

16. The method of claim 9, further comprising camping on the first serving eNB and the second serving eNB simultaneously, the camping comprising:

attaching to the first serving eNB using a first attach procedure; and attaching to the second serving eNB using a second attach procedure while attached to the first serving eNB.

17. A user equipment (UE) comprising:

one or more transceivers configured to access assistance data that indicates positioning signal parameters associated with at least a first serving eNodeB (eNB) associated with a first frequency, a second serving eNB associated with a second frequency, and one or more neighbor eNBs;

a processor coupled to the one or more transceivers and configured to:

determine that the one or more neighbor cells operate on the second frequency;

in response to the determination that the one or more neighbor cells operate on the second frequency, select for measurement the second serving eNB; and

18. The UE of claim 17, wherein the processor is further configured to:

determine that the one or more neighbor cells operate on the first frequency; in response to the determination that the one or more neighbor cells operate on the first frequency, select for measurement the first serving eNB.

19. The UE of claim 17, further comprising receiving a request for Reference Signal Time Difference (RSTD) measurements, wherein the positioning signal parameters are Positioning Reference Signaling (PRS) parameters.

20. The UE of claim 17, wherein the UE is configured for dual connectivity, the first serving eNB is a Master eNodeB (MeNB) associated with a Master Cell Group (MCG) and the second serving eNB is a Secondary eNodeB (SeNB) associated with a Secondary Cell Group (SCG).

21. The UE of claim 20, wherein the MCG includes the MeNB and at least one neighbor eNB of the one or more neighbor eNBs, the processor being further configured to:

22. The UE of claim 17, wherein the one or more transceivers are further configured to:

23. The UE of claim 17, wherein the UE is further configured to camp on the first serving eNB and the second serving eNB simultaneously, wherein:

to camp on the first serving eNB, the processor is further configured to attach to the first serving eNB using a first attach procedure; and

24. A method comprising:

accessing assistance data that indicates positioning signal parameters associated with at least a first serving eNodeB (eNB) associated with a first frequency, a second serving eNB associated with a second frequency, and one or more neighbor eNBs; determining that the one or more neighbor cells operate on the second frequency;

in response to the determination that the one or more neighbor cells operate on the second frequency, selecting for measurement the second serving eNB; and in response to the selecting, measuring a time of arrival of a positioning signal corresponding to the selected eNB.

25. The method of claim 24, further comprising:

determining that the one or more neighbor cells operate on the first frequency; in response to the determination that the one or more neighbor cells operate on the first frequency, selecting for measurement the first serving eNB.

26. The method of claim 24, further comprising receiving a request for Reference Signal Time Difference (RSTD) measurements, wherein the positioning signal parameters are Positioning Reference Signaling (PRS) parameters.

27. The method of claim 24, wherein the UE is configured for dual connectivity, the first serving eNB is a Master eNodeB (MeNB) associated with a Master Cell Group (MCG) and the second serving eNB is a Secondary eNodeB (SeNB) associated with a Secondary Cell Group (SCG).

28. The method of claim 27, wherein the MCG includes the MeNB and at least one of the one or more neighbor eNBs, the method further comprising:

measuring a time of arrival of a positioning signal corresponding to the at least one neighbor eNB of the one or more neighbor eNBs; and

29. The method of claim 24, further comprising:

30. The method of claim 24, further comprising camping on the first serving eNB and the second serving eNB simultaneously, the camping comprising: attaching to the first serving eNB using a first attach procedure; and

attaching to the second serving eNB using a second attach procedure while attached to the first serving eNB.