This application claims the benefit of Swedish Patent Application No. 1930094-6, filed Mar. 25, 2019, and Swedish Patent Application No. 1930095-3, filed Mar. 25, 2019. The entireties of the aforementioned patent applications are incorporated herein by reference.
The technology of the present disclosure relates generally to operations of a network node and/or a wireless communications device in a wireless communications network and, more particularly, to methods and apparatus for positioning of a device.
In existing wireless communications systems (e.g., 3G or 4G-based systems), estimations of a device position are generally considered acceptable when regulatory positioning requirements are satisfied. For example, for emergency calls, a position estimate is only required to be accurate within 50 meters in 4G systems. Positioning is an important feature under consideration of the Third Generation Partnership Project (3GPP) for 5G systems such as New Radio (NR). The specification is targeting use cases beyond emergency call services (i.e. regulatory requirements), such as commercial use-cases and 5G systems may be expected to provide sub-meter positioning accuracy.
Cellular-based positioning may be downlink based or uplink based. In legacy systems, timing measurements and angle measurements are common techniques in downlink-based positioning. For instance, observed time difference of arrival (OTDOA) is a multilateration technique in 4G systems. In this technique, a base station (eNB) transmits positioning reference signals (PRS). A user equipment (UE) estimates time of arrival (TOA) based on the received PRS. The TOA measured from the PRS of multiple base stations are subtracted from a TOA corresponding to a reference base station to generate OTDOA measurements. The UE reports the OTDOA measurements or measured time difference (e.g. Reference Signal Time Difference (RSTD)) to a location server. The location server estimates the position of the UE based on the RSTD report and known coordinates of the base stations. Another technique, such as Enhanced cell ID with LTE systems, involves a base station estimating an angle of arrival (AoA) of a signal transmitted by the UE. The base station exploits phase difference from at least two receive antennas to estimate the AoA, for example.
One approach in legacy systems for uplink-based positioning is uplink time difference of arrival (UTDOA). With this approach, a user equipment (UE) transmits a reference signal, which is received by one or more base stations or dedicated location measurement units (LMUs). The base stations (or LMUs) estimate a time of arrival and report the estimate to a location server to estimate the UE's position (e.g. via multilateration if multiple base stations measure a time of arrival).
With legacy systems, radio access technology (RAT) dependent positioning (e.g. uplink-based or downlink-based positioning) may be performed when a UE is in connected mode. In legacy systems, the use-case for RAT dependent positioning is typically limited to positioning to support emergency calling and, as such, the UE would already in connected mode for the emergency call. In 5G NR systems, use-cases for positioning may not be limited to emergency call support and may include commercial use-cases. In addition, 5G use-cases may demand various parameters for positioning results (e.g. vertical positioning, horizontal positioning, mobility, and/or latency) and various accuracy requirements (e.g. within hundreds of meters, within tens of meters, or sub-meter). These use-cases may not otherwise require the UE to be in connected mode as with emergency calls. In such situations, positioning that is dependent on being in connected mode may cause long latency in getting a position of the UE, incur additional signaling overhead, and increase UE power consumption due to signaling between the UE and a network node to enter and maintain connected mode. While RAT independent techniques (e.g. GPS or other sensors) may be utilized by the UE for positioning, reporting a position acquired with these techniques to the network may still depend on being in connected mode.
The disclosed approach supports positioning of a UE while the UE is in idle mode. The UE may be provided a positioning configuration usable to execute positioning while in idle mode. The positioning configuration may indicate positioning resources usable by the UE while in idle mode. The positioning resources may include uplink resources to support uplink-based positioning and/or downlink resources to support downlink-based positioning. For example, the UE may utilize uplink resources to transmit uplink reference signals to a set of network nodes participating in positioning (e.g. a serving base station and/or one or more neighboring base stations) while in idle mode. Similarly, the UE, while in idle mode, may receive downlink reference signals respectively transmitted by the set of network nodes using the downlink resources. Still further, in another example, the UE may receive downlink reference signals and also transmit uplink reference signals. In either case, a recipient of a reference signal performs a measurement on the received signal. Measurement information associated with uplink-based measurements, downlink-based measurements, or both may be utilized to compute a position of the UE.
According to one aspect of the disclosure, a method for positioning of a wireless communications device performed by a network node includes determining uplink positioning resources dedicated for uplink-based positioning in idle mode, the uplink positioning resources being usable by the wireless communications device to facilitate positioning of the wireless communications device while in idle mode; and transmitting, to the wireless communications device, positioning configuration information indicating at least the uplink positioning resources to be used by the wireless communications device in idle mode.
According to one embodiment of the method, the uplink positioning resources dedicated for uplink-based positioning in idle mode specify at least one of a time/frequency resource allocated to the uplink positioning resources, a time offset relative to a reference time, a periodicity of the uplink positioning resources, a duration of the uplink positioning resources, or a sequence identifier of the uplink positioning resources.
According to one embodiment of the method, the wireless communications device is in connected mode when the network node transmits the positioning configuration information.
According to one embodiment of the method, the positioning resources are specific to the wireless communications device.
According to one embodiment of the method, the positioning resources are assigned to a group of wireless communications devices that includes the wireless communications device.
According to one embodiment of the method, the positioning configuration information further indicates uplink data resources for downlink-based positioning measurement results.
According to one embodiment, the method includes receiving downlink-based measurement information from the wireless communications device using the uplink data resources.
According to one embodiment, the method includes determining downlink positioning resources for use when the wireless communications device is in idle mode.
According to one embodiment of the method, the positioning configuration information indicates a timing relationship between the downlink resources and the uplink resources.
According to one embodiment of the method, determining the downlink resources is based on determining the uplink resources or determining the uplink resources is based on determining the downlink resources.
According to one embodiment of the method, the method includes receiving one or more uplink reference signals transmitted by the wireless communications device using the uplink positioning resources; measuring the one or more uplink reference signals received; and sending a measurement report to a positioning computation node.
According to one embodiment, the method includes sending a measurement report to a positioning computation node, wherein the measurement report is based on the downlink-based measurement information and uplink-based measurement information.
According to one embodiment, the method includes transmitting an activation signal to the wireless communications device to initiate uplink-based positioning of the wireless communications device while in idle mode.
According to one aspect of the disclosure, a method for facilitating positioning of a device performed by a wireless communications device includes receiving positioning configuration information from a network node, the positioning configuration information configures the wireless communications device for uplink-based positioning while in idle mode and includes at least uplink positioning resources dedicated for uplink-based positioning in idle mode; and performing a positioning operation while in idle mode in accordance with the positioning configuration information.
According to one embodiment of the method, the uplink positioning resources dedicated for uplink-based positioning in idle mode specify at least one of a time/frequency resource allocated to the uplink positioning resources, a time offset relative to a reference time, a periodicity of the uplink positioning resources, a duration of the uplink positioning resources, or a sequence identifier of the uplink positioning resources.
According to one embodiment of the method, receiving the positioning configuration information occurs while the wireless communications device is in connected mode
According to one embodiment of the method, performing the positioning operation includes transmitting uplink reference signals, using the uplink positioning resources, to one or more network nodes.
According to one embodiment of the method, the positioning configuration information further indicates downlink positioning resources and wherein performing the positioning operation further includes measuring downlink reference signals transmitted by one or more network nodes in accordance with the downlink positioning resources.
According to one embodiment of the method, the positioning configuration information indicates a timing relationship between resources for the downlink reference signals and resources for the uplink reference signals.
According to one embodiment, the method includes selecting one or more transmit beams for the uplink reference signals.
According to one embodiment of the method, selecting the one or more transmit beams is based on receive beams of the wireless communications device associated with downlink reference signals
According to one embodiment, the method includes transmitting downlink-based measurement information based on measurements of the downlink reference signals received.
According to one embodiment of the method, the positioning configuration information further indicates uplink data resources for transmitting the downlink-based measurement information in idle mode.
According to one embodiment, the method includes using a payload encryption from a previously obtained security context for transmitting the downlink-based measurement information.
According to one embodiment of the method, the positioning configuration information indicates one or more network nodes participating in the positioning operation.
According to one embodiment, the method includes, prior to performing the positioning operation, performing downlink measurements of the one or more network nodes; and identifying a serving network node based on the downlink measurements to verify validity of the positioning configuration information.
According to one embodiment of the method, verifying the validity of the positioning configuration information includes comparing the identity of the identified serving network node with corresponding positioning configuration information.
According to one embodiment, the method includes receiving an activation signal from the network node; and initiating the positioning operation upon receiving the activation signal.
According to another aspect of the disclosure, a wireless communications node configured to operate in a wireless communications network includes a wireless interface over which wireless communications with one or more network nodes are carried out; and a control circuit configured to: receive positioning configuration information from a network node of the one or more network nodes, the positioning configuration information configures the wireless communications device for uplink-based positioning while in idle mode and include at least uplink positioning resources dedicated for uplink-based positioning in idle mode; and; and perform a positioning operation while in idle mode in accordance with the positioning configuration information.
According to one embodiment of the wireless communications device, the uplink positioning resources dedicated for uplink-based positioning in idle mode specify at least one of a time/frequency resource allocated to the uplink positioning resources, a time offset relative to a reference time, a periodicity of the uplink positioning resources, a duration of the uplink positioning resources, or a sequence identifier of the uplink positioning resources.
According to one embodiment of the wireless communications device, the control circuit is further configured to receive the positioning configuration information while in connected mode.
According to one embodiment of the wireless communications device, the control circuit is further configured to transmit uplink reference signals, using the uplink positioning resources, to one or more network nodes.
According to one embodiment of the wireless communications device, the positioning configuration information further indicates downlink positioning resources and the control circuit is further configured to measure downlink reference signals transmitted by the one or more network nodes in accordance with the downlink positioning resources.
According to one embodiment of the wireless communications device, the positioning configuration information indicates a timing relationship between resources for the downlink reference signals and resources for the uplink reference signals.
According to one embodiment of the wireless communications device, the control circuit is further configured to select one or more transmit beams for the uplink reference signals.
According to one embodiment of the wireless communications device, the control circuit is further configured to transmit downlink-based measurement information based on measurements of the downlink reference signals received.
According to one embodiment of the wireless communications device, when in connected mode, the control circuit is further configured to transmit downlink-based measurement information based on measurements of the downlink reference signals received.
According to one embodiment of the wireless communications device, wherein the control circuit is further configured to measure downlink references signals transmitted by the one or more network nodes; and transmit uplink reference signal, using the uplink resources, to the one or more network nodes.
According to one embodiment of the wireless communications device, the positioning configuration information indicates a timing relationship between resources for the downlink reference signals and resources for the uplink reference signals.
According to one embodiment of the wireless communications device, the control circuit is further configured to transmit downlink-based measurement information based on measurements of the downlink reference signals received.
According to one embodiment of the wireless communications device, the positioning configuration information further indicate uplink data resources for transmitting the downlink-based measurement information in idle mode.
According to one embodiment of the wireless communications device, the control circuit is further configured to use a payload encryption from a previously obtained security context to transmit the downlink-based measurement information.
According to one embodiment of the wireless communications device, the positioning configuration information indicates one or more network nodes participating in the positioning operation.
According to one embodiment of the wireless communications device, the control circuit is further configured to: perform downlink measurements of the one or more network nodes; and identify a serving network node based on the downlink measurements to verify validity of the positioning configuration information.
According to one embodiment of the wireless communications device, the control circuit is further configured to verify validity of the positioning configuration information by comparing an identity of the identified serving network node with corresponding positioning configuration information.
According to one embodiment of the wireless communications device, the control circuit is further configured to receive an activation signal from the network node; and initiate the positioning operation upon receiving the activation signal.
According to another aspect of the disclosure, a network node configured to operate in a wireless communications network includes a wireless interface over which wireless communications with a wireless communications device are carried out; an interface over which communications with a core network are carried out; and a control circuit configured to: determine uplink positioning resources dedicated for uplink-based positioning idle mode, the uplink positioning resources being usable by the wireless communications device to facilitate positioning of the wireless communications device while in idle mode; and transmit, to the wireless communications device, positioning configuration information indicating at least the uplink positioning resources to be used by the wireless communications device in idle mode.
According to one embodiment of the network node, the uplink positioning resources dedicated for uplink-based positioning in idle mode specify at least one of a time/frequency resource allocated to the uplink positioning resources, a time offset relative to a reference time, a periodicity of the uplink positioning resources, a duration of the uplink positioning resources, or a sequence identifier of the uplink positioning resources.
According to one embodiment of the network node, the wireless communications device is in connected mode when the network node transmits the positioning configuration information.
According to one embodiment of the network node, the positioning resources are specific to the wireless communications device.
According to one embodiment of the network node, the positioning resources are assigned to a group of wireless communications devices that includes the wireless communications device.
According to one embodiment of the network node, the positioning configuration information further indicates uplink data resources for downlink-based positioning measurements results.
According to one embodiment of the network node, the positioning configuration information indicates a timing relationship between the downlink resources and the uplink resources.
According to one embodiment of the network node, the control circuit is further configured to receive downlink-based measurement information from the wireless communications device using the uplink data resources.
According to one embodiment of the network node, the control circuit is further configured to send a measurement report to a positioning computation node. The measurement report is based on the downlink-based measurement information and/or uplink-based measurement information.
According to one embodiment of the network node, the control circuit is further configured to determine downlink positioning resources for use when the wireless communication device is in idle mode.
According to one embodiment of the network node, the positioning configuration information indicates a timing relationship between the downlink positioning resources and the uplink positioning resources.
According to one embodiment of the network node, the control circuit is further configured to transmit an activation signal to the wireless communications device to initiate uplink-based positioning of the wireless communications device while in idle mode
Embodiments will now be described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. It will be understood that the figures are not necessarily to scale. Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.
The network environment is relative to an electronic device, such as a user equipment (UE) 100. As contemplated by 3GPP standards, the UE may be a mobile radiotelephone (a “smartphone”). Other exemplary types of UEs 100 include, but are not limited to, a gaming device, a media player, a tablet computing device, a computer, a camera, and an internet of things (IoT) device. Since aspects of the disclosed techniques may be applicable to non-3GPP networks, the UE 100 may be more generically referred to as a wireless communications device or a radio communications device.
The network environment includes a wireless communications network 102 that may be configured in accordance with one or more 3GPP standards, such as a 3G network, a 4G network or a 5G network. The disclosed approaches may apply to other types of networks.
In instances where the network 102 is a 3GPP network, the network 102 includes a core network (CN) 104 and a radio access network (RAN) 106. The core network 104 provides an interface to a data network (DN) 108. The DN 108 represents operator services, connection to the Internet, third party services, etc. Details of the core network 104 are omitted for simplicity of description, but it is understood that the core network 104 includes one or more servers that host a variety of network management functions, examples of which include, but are not limited to, a user plane function (UPF), a session management function (SMF), a core access and mobility management function (AMF), an authentication server function (AUSF), a network exposure function (NEF), a network repository function (NRF), a policy control function (PCF), a unified data management (UDM), an application function (AF), and a network slice selection function (NSSF). In addition, the core network 104 may include a positioning computation node 105 configured to estimate a position of UE 100 based on measurements reported by the UE 100 for downlink-based positioning and/or measurements reported by the RAN 106, for example, with uplink-based positioning. As described later, the positioning computation node 105 may request the UE 100 and/or RAN 106 to support positioning in idle mode. Further, while shown in
The RAN 106 includes a plurality of RAN nodes 110. In the illustrated example, there are three RAN nodes 110a, 110b, and 110c. Fewer than or more than three RAN nodes 110 may be present. For 3GPP networks, each RAN node 110 may be a base station such as an evolved node B (eNB) base station or a 5G generation gNB base station. The RAN node 110 may include one or more Tx/Rx points (TRPs). Since aspects of the disclosed techniques may be applicable to non-3GPP networks, the RAN nodes 110 may be more generically referred to as network access nodes, an alternative example of which is a WiFi access point.
A radio link may be established between the UE 100 and one of the RAN nodes 110 for providing wireless radio services to the UE 100. The RAN node 110 to which the radio link is established will be referred to as the serving RAN node 110 or serving base station. Other RAN nodes 110 may be within communication range of the UE 100. The RAN 106 is considered to have a user plane and a control plane. The control plane is implemented with radio resource control (RRC) signaling between the UE 100 and the RAN node 110. Another control plane between the UE 100 and the core network 104 may be present and implemented with non-access stratum (NAS) signaling.
With additional reference to
The RAN node 110 also includes a wireless interface 114 for establishing an over the air connection with the UE 100. The wireless interface 114 may include one or more radio transceivers and antenna assemblies to form the TRP(s). The RAN node 110 also includes an interface 116 to the core network 104. The RAN node 110 also includes an interface (not shown) to one or more neighboring RAN nodes 110 for conducting network coordination in the RAN 106.
In accordance with a further aspect, uplink-based positioning may involve a location measurement unit (LMU). The LMU may be a separate node (e.g. within the RAN 106) or it may be co-located with or a component of the RAN node 110. For example, the LMU may be a computer-based system communicatively coupled with and positioned near the RAN node 110. Alternatively, the LMU may be integrated into the RAN node 110 and may be implemented in by the logical instructions stored in the memory of the control circuit 112.
With additional reference to
The UE 100 includes a wireless interface 122, such as a radio transceiver and antenna assembly, for establishing an over the air connection with the serving base station 110. In some instances, the UE 100 may be powered by a rechargeable battery (not shown). Depending on the type of device, the UE 100 may include one or more other components. Other components may include, but are not limited to, sensors, displays, input components, output components, electrical connectors, etc.
In
The positioning computation node 105 may be implemented as a computer-based system that is capable of executing computer applications (e.g., software programs) that carry out functions of the computation node 105. As is typical for a computer platform, the positioning computation node 105 may include a non-transitory computer readable medium, such as a memory 126 that stores data, information sets and software, and a processor 124 for executing the software. The processor 124 and the memory 126 may be coupled using a local interface 127. The local interface 127 may be, for example, a data bus with accompanying control bus, a network, or other subsystem. The computation node 105 may have various input/output (I/O) interfaces for operatively connecting to various peripheral devices, as well as one or more interfaces 128. The interface 128 may include for example, a modem and/or a network interface card. The communications interface 128 may enable the computation node 105 to send and receive data signals to and from other computing devices in the core network 104, the RAN 106, and/or in other locations as is appropriate.
As described above, legacy positioning techniques are performed during connected mode. The reliance on connected mode may result in situations where a wireless communications network is unable to locate a wireless communications device in, for example, an idle or inactive state for a long period of time, particular with longer durations of discontinuous reception (DRX) being employed. Moreover, there are multiple steps involved to trigger and execute a change from idle mode to connected mode. Such steps include, for example, paging, random access procedure, radio resource control (RRC) message exchange, etc. These steps not only add to the latency in getting a position of the wireless communications device, but also incur additional signaling overhead, and increase power consumption by the wireless communications device. Techniques will be described for supporting positioning of a wireless communications device while in idle mode to enable the wireless communications network to readily locate the wireless communications device while also reducing latency, resource utilization, and power consumption.
A node of the wireless communications network, for example the positioning computation node 105, and/or a wireless communications device may request positioning operations during idle mode. The request may be sent to a set of network nodes selected to participate in idle mode positioning. The network nodes may include a serving network node (e.g. RAN node 110) of a wireless communications device (e.g. UE 100), neighboring network nodes, and/or location measurement units (LMUs), which may be associated or integrated with the network nodes. The request may indicate a required accuracy desired for the positioning, desired parameters for a positioning estimate, and/or may also instruct on a configuration for idle mode positioning. According to various aspects, the configuration may indicate a positioning scheme to be employed (e.g. uplink-based positioning, downlink-based positioning, or both), positioning resources to be used to facilitate positioning (e.g. resources uplink-based positioning, resources for downlink-based positioning, and/or resources for both), a set of network nodes (e.g. RAN nodes) selected to facilitate positioning, and/or measurement intervals for positioning measurements. The configuration may be used by the serving network nodes, neighboring network nodes, and/or the wireless communications device to facilitate positioning of the wireless communications. For instance, the configuration generally guides how a positioning operation is performed for a given wireless communications device within the wireless communications network. In accordance with embodiments described herein, the configuration may be utilized when the wireless communications device is in idle mode or inactive mode. In one example, the configuration may be based on the desired accuracy.
The serving network node may transmit configuration information to wireless communication device in response to the request. For instance, the serving network node may transmit one or more control messages to the wireless communications device. The one or more control messages may include the configuration information, which indicates a configuration of idle mode positioning as described above. Upon receiving the configuration information, the wireless communications device may perform operations to facilitate positioning even after a transition from connected mode to idle mode. In another example, the wireless communications device may trigger activation of idle mode positioning functionality upon receiving the configuration information.
Turning to
As mentioned above, the positioning computation node 105 may send a request for idle mode positioning to a serving network node (e.g. RAN node 110a) and neighboring network nodes (e.g. RAN nodes 110b-c) selected to supported positioning of UE 100. The serving RAN node 110a may transmit positioning configuration information to UE 100 to enable the UE 100 to perform positioning operations while in idle mode. The positioning configuration information may also be shared with neighbor RAN nodes 110b-c. For instance, the positioning configuration information may include a common configuration utilized for idle mode positioning within a group of cells (e.g. for a group of network nodes). Alternatively, each network node may have a specific configuration for UEs served by the network node or located within a cell of the network node. While shown in
In accordance with various examples, idle mode positioning may be uplink-based, downlink-based, or a combination of uplink and downlink-based. The positioning technique employed may be indicated in the positioning configuration information. In addition, the positioning configuration information may indicate positioning resources allocated to support idle mode positioning.
In a first example, uplink-based positioning may be performed while UE 100 is in idle mode. In this example, the positioning resources indicated in the positioning configuration information may include uplink resources for the UE 100 to transmit one or more uplink references signals to RAN nodes 110 (or LMUs). The uplink reference signal may be an uplink positioning reference signal (UL-PRS), a sounding reference signal (SRS), or substantially any other reference signal capable of being measured for positioning purposes. UE 100 may receive one or more resource configurations by which to transmit the one or more uplink reference signals. The resource configurations may indicate time and frequency information allocated for the uplink reference signals, a time offset (relative to a reference point), a periodicity and/or duration of uplink resources for uplink reference signals (e.g. an interval), and/or a sequence ID.
The positioning configuration information may also indicate a set of network nodes (e.g. RAN nodes 110a-c) selected to receive the uplink reference signals transmitted by UE 100. The RAN nodes 110a-c, upon receiving respective uplink reference signals, compute positioning measurements on the received signals. The positioning measurements may be timing-based (e.g., TOA, Relative TOA (RTOA), UTDOA, etc.) and/or signal strength-based (e.g. reference signal received power (RSRP), received signal strength indication (RSSI), etc.). One or more receivers of the uplink reference signal, such as RAN nodes 110, may generate positioning measurements (also generally referred to herein as uplink measurements) and report the measurements to the positioning computation node 105 in a positioning measurement report or uplink measurement report. The RAN nodes 110 may send separate (e.g. individual) reports the positioning computation node 105. Alternatively, neighboring RAN nodes 110b-c may send the measurements to a serving RAN node 110a. The serving RAN node 110a collects the measurements from the neighboring RAN nodes 110b-c and sends an aggregate report to the positioning computation node 105. The positioning computation node 105 may estimate a position of UE 100 based on the reported uplink or positioning measurements.
UE 100 may transmit the uplink reference signals via a specific beam transmission. For instance, UE 100 may transmit the uplink reference signal on transmit beam 101a, 101b, and/or 101c as shown in
In the example depicted in
Prior to transmission of uplink reference signals, UE 100 may perform downlink measurements of signals from RAN nodes 110. The measurements may identify the serving cell of UE 100 so as to verify the positioning configuration information. For instance, prior to entering idle mode, the UE 100 may be provided the positioning configuration information by RAN node 110a to support idle mode positioning. However, while in idle mode, it is possible that the UE 100 has moved to a different serving cell or moved to a different group of cells having a different configuration for idle mode positioning. In such cases, the positioning configuration information received by the UE 100 from the RAN node 110a may be invalid and the UE 100 may need an updated configuration. Thus, by verifying the serving cell identity/status prior to transmitting uplink reference signals, the UE 100 can ensure positioning operations will occur as expected without unintended adverse effects (e.g. interference, etc.).
In addition, the downlink measurements may enable UE 100 to select appropriate transmit beams for the uplink reference signals if beam operations are employed. For example, via downlink measurements the UE 100 may identify a respective UE-side receive beam for each RAN node 110. If beam correspondence is maintained, a corresponding transmit beam may be selected based on the identified receive beam. Beam correspondence refers to a situation where UE 100 may derive an uplink (e.g. transmit) beam based on a downlink beam (and vice versa). For example, if UE 100 receives a downlink signal on beam index 1 (e.g. best received beam is beam index 1), the uplink beam (e.g. transmit beam) may also use beam index 1. If beam correspondence is not maintained, there may be some deviation between a downlink beam direction and an uplink beam direction. Accordingly, UE 100 may select transmit beams to perform sequential beam sweeping, for example, to overcome the deviation.
In another example, downlink-based positioning may be performed while UE 100 is in idle mode. With downlink-based positioning, the RAN nodes 110 transmit downlink reference signals, which are measured by the UE 100. The downlink reference signal may, in one example, may be a positioning reference signal (PRS) similar to PRS in legacy systems. In another example, other existing signals generally utilized to assist data transmissions may be used for positioning purposes. For instance, channel state information reference signal (CSI-RS), tracking reference signal (TRS), and/or synchronization signal block (SSB) may be utilized as downlink reference signals for positioning purposes.
To activate downlink-based positioning in idle mode, the positioning configuration information received by UE 100 may include an indication signal to notify the UE 100 to continue receiving downlink reference signals and computing positioning measurements (e.g. time-based or signal-strength-based) while in idle mode. The positioning configuration information may indicate a set of network nodes (e.g. RAN nodes 110a-c) from which signals are to be measured for positioning. In addition, the positioning configuration information may indicate downlink resources (e.g. time and frequency information, time offset, etc.) for the downlink reference signals to be measured by UE 100. Further, the positioning configuration information may provide an interval (e.g. measurement interval) indicating a periodicity of positioning measurements and a duration of each measurement window. For example, if the desired accuracy indicates a high level of precision, then more frequency measurements may be needed.
UE 100 may compute a positioning estimate based on positioning measurements of received downlink reference signals. For instance, if UE 100 knows the coordinates of RAN nodes 110a-c, then UE 100 may compute the estimate from the positioning measurements. In another embodiment, the UE 100 may report downlink measurement information (e.g. a measurement report) and/or a computed positioning estimate to the positioning computation node 105 (via serving RAN node 110a, for example) when connected mode is established. The downlink measurement information may include a time stamp indicating a time at which the UE 100 performed the measurement.
The UE 100 may include beam information with the positioning measurements. For example, the RAN nodes 110a-c may employ beam sweeping to transmit downlink reference signals on a set of configured beams. The beam information may correspond to UE beams 101a-c and/or RAN node beams 111a-c.
In yet another example, a combination of uplink-based and downlink-based positioning may be performed while UE 100 is in idle mode. With this approach, positioning measurements are acquired on a network node side (e.g. by a RAN node 110 or LMU) and also at the UE 100. Accordingly, UE 100 may receive and measure downlink references signals and also transmit uplink reference signals. The positioning configuration information may indicate uplink resources and downlink resources as described above, as well as the other configuration information described in the context of uplink-based or downlink-based positioning respectively. However, additional information may be indicated to support the combination approach. For example, a timing relationship between resources for uplink reference signals and resources for downlink reference signals may be specified. For instance, the uplink resources may be T subframes before or after a starting time of downlink resources. In another example, for instance, the timing relationship may be utilized to determine the resources for downlink-based positioning based on determining the resources for uplink-based positioning or determine the resources for uplink-based positioning is based on determining the resources for downlink-based positioning. That is, resources for one direction may be determined based on resources for the other direction and the timing relationship.
In the combination approach, results of a first measurement can be transmitted in a second transmission also utilized to transmit reference signals for a second measurement. For example, UE 100 can receive and measure downlink reference signals from RAN nodes 110. Downlink measurement information (e.g. time stamps, signal strength measurements, ToA measurements, etc.) can be transmitted along with the uplink reference signals to be measured by the RAN nodes 110. The downlink measurement information can be provided to the positioning computation node 105 along with measurements reports form the RAN nodes 110. Thus, the positioning computation node 105 may generate a positioning estimate based on both UE-side and network-side measurements.
The uplink resources indicated in the positioning configuration information may include uplink data resources to accommodate the downlink measurement information. Data transmissions often have encrypted payloads. The UE 100 may utilize a payload encryption from a previously obtained security context to transmit the downlink measurement information. Further, the measurement information may include beam information as described above.
Turning to
To activate positioning in idle mode, the positioning computation node 130 may send a positioning request 144 to the serving base station 132 and the neighbor base stations 134 selected to facilitate positioning. The positioning request 144 may indicate a desired accuracy and other requirements for the positioning estimate. In response to the positioning request 144, the serving base station 132 sends positioning configuration information 146 to the UE 136. The positioning configuration information 146 may include positioning resources usable by the UE 136 while in idle mode. Furthermore, base-stations 132, 134 may be configured with common positioning resources in order to receive the signals from UE 136. For example, in the embodiment illustrated in
While in idle mode, UE 136 may perform positioning operations in accordance with the positioning configuration information 146. The configuration information 146 may be serving-cell-specific or specific to a group of cells. Prior to performing such operations, however, UE 136 may confirm a validity of the positioning configuration information 146. For example, the UE 136 may perform downlink measurements 152 to identify a cell in which it is located. When the identified cell corresponds to the positioning configuration information 146, the known configuration is verified. If the UE 136 has moved to a different serving cell or different group of cells since receiving the positioning configuration information 146, the information may no longer be valid and the UE 136 may require a new configuration. The downlink measurements 152 may also provide beam information related to the serving base station 132 and neighbor base stations 134 so that the UE 136 may select appropriate transmit beams for the uplink reference signals. For example, if beam correspondence is maintained, a corresponding transmit beam may be selected based on a receive beam for reference signals from the serving base station 132 and/or neighbor base stations 134.
Transmission of uplink reference signals may commence based on resource and timing information indicated in the positioning configuration information 146. At an appropriate point in time based on the positioning configuration information 146, the serving base station 132 prepares for reception 158, the neighbor base stations 134 prepare for reception 160, and the UE 136 prepares for transmission 156.
Optionally, the serving base station 132 may transmit an activation signal 154 to the UE 136 to trigger transmission of uplink reference signals. The activation signal 154 may also be sent to the neighbor base stations 134 to alert the neighbor base stations 134 to start measuring uplink reference signals. In response to the activation signal 154 and/or at an appropriate point in time based on the positioning configuration information 146, the serving base station 132 prepares for reception 158, the neighbor base stations 134 prepare for reception 160, and the UE 136 prepares for transmission 156.
The UE 136 may utilize one or more transmit beams to transmit uplink reference signals 162 to serving base station 132, neighbor base stations 134 (e.g. selected to facilitate positioning). The neighbor base stations 134 perform respective positioning measurements 164 on the uplink reference signals 162. The serving base station 132 also performs a positioning measurement 166 on the uplink reference signals 162 received. The base stations 132 and 134 send respective measurement reports 168 to the positioning computation 105, which calculates a positioning estimate 170 based on the reports 168. The reports 168 may include positioning measurement values (e.g. a positioning timing measurement or positioning signal strength measurement) along with beam information (e.g. transmit beam information and/or receive beam information).
In
After UE 136 performs downlink measurements 152 to verify a configuration for idle mode positioning, the UE 136 may prepare for reception 172 of downlink reference signals. The serving base station 132 and the neighbor base stations 134 may transmit downlink reference signals 174 to UE 136. The UE 136 performs positioning measurements 176 based on the received downlink reference signals 174.
Optionally, the UE 136 may compute a positioning estimate 178 if coordinates are known for the serving base station 132, the neighbor base stations 134, and other base stations from which measurement are made. In such instances, the UE 136 may not need to perform the remaining steps shown in
Alternatively, if the UE 136 does not compute a positioning estimate, which may be computed by the positioning computation node 130. Accordingly, the UE 136 may store downlink measurements for later transmission to the positioning computation node 130. For example, the UE 136 can establish connected mode at 180 and transmit downlink measurement information 182 to the positioning computation node 130 (via the serving base station 132, for example). The positioning computation node 130 may compute a positioning estimate 184 based on the downlink measurement information 182. The downlink measurement information 182 may include positioning measurement values (e.g. a positioning timing measurement or positioning signal strength measurement) along with beam information (e.g. transmit beam information and/or receive beam information). The downlink measurement information 182 may also comprise time stamps indicating a time when the positioning measurements were performed.
In
After UE 136 performs downlink measurements 152 to verify a configuration for idle mode positioning, the UE 136 may receive downlink reference signals 186. The serving base station 132 and the neighbor base stations 134 may transmit downlink reference signals 186 to UE 136. The UE 136 performs positioning measurements 188 based on the received downlink reference signals 186. Optionally, the UE 136 may computer a positioning estimate 190 if coordinates are known for the serving base station 132 and the neighbor base stations 134. Alternatively, the UE 136 may store downlink measurement information for later transmission. Using uplink resources indicated in the positioning configuration information 146, the UE 136 may utilize one or more transmit beams to transmit uplink reference signals 192 to serving base station 132 and neighbor base stations 134. The neighbor base stations 134 perform respective positioning measurements 194 based on the uplink reference signals 192. The serving base station 132 also performs a positioning measurement 196 on the uplink reference signals 192 received. Using uplink data resources indicated in the positioning configuration information 146, UE 136 may transmit downlink measurement information 198 to the serving base station 132 while in idle mode. The UE 136 may utilize a payload encryption from a previously acquired security context to transmit the downlink measurement information 198 may include positioning measurement values (e.g. a positioning timing measurement or positioning signal strength measurement) along with beam information (e.g. transmit beam information and/or receive beam information).
The base stations 132 and 134 may send respective measurement reports 200 to the positioning computation 130, which calculates a positioning estimate 202 based on the reports 200. The reports 200 may include positioning measurement values (e.g. a positioning timing measurement or positioning signal strength measurement) along with beam information (e.g. transmit beam information and/or receive beam information). In addition, the report 200 from the serving base station 132 may include the downlink measurement information 198 transmitted by the UE 136. Accordingly, the positioning estimate 202 is based on network-side and UE-side measurements of reference signals.
It is to be appreciated that the above sequences described in
Turning to
In block 218, the wireless communications device may switch from connected mode to idle mode. In block 220, while in idle mode, the wireless communications device may perform positioning operations in accordance with the positioning configuration information. Turning to
For uplink-based positioning, the wireless communications device, in block 228, transmits uplink reference signals to the one or more network nodes participating in positioning. The wireless communications device transmit the uplink reference signals using transmit beams determined via the downlink measurements and/or using uplink resources indicated in the positioning configuration information.
For downlink-based positioning, the wireless communications device, in block 230, receives downlink reference signals transmitted by the one or more network nodes participating in positioning. The downlink reference signals may be transmitted using downlink resource indicated in the positioning configuration information. In block 232, the wireless communications device performs positioning measurements based on the downlink reference signals. The positioning measurements may be timing-based and/or signal-strength-based and may also include beam information. In block 234, the wireless communications device may transmit downlink-based measurement information to a positioning computation node (via a serving network node for example). In one example, the wireless communications device may move to connected mode to transmit the downlink-based measurement information.
For UL/DL-based positioning, the wireless communications device, in block 236, receives downlink reference signals transmitted by the one or more network nodes participating in positioning. The downlink reference signals may be transmitted using downlink resource indicated in the positioning configuration information. In block 238, the wireless communications device performs positioning measurements based on the downlink reference signals. The positioning measurements may be timing-based and/or signal-strength-based and may also include beam information. In block 240, transmits uplink reference signals to the one or more network nodes participating in positioning. The wireless communications device transmit the uplink reference signals using transmit beams determined via the downlink measurements and/or using uplink resources indicated in the positioning configuration information. In block 242, the wireless communications device may transmit downlink-based measurement information that includes positioning measurements based on the downlink reference signals. The wireless communications device may transmit the downlink-based measurement information, while in idle mode, using uplink data resources indicated in the positioning configuration information.
Although certain embodiments have been shown and described, it is understood that equivalents and modifications falling within the scope of the appended claims will occur to others who are skilled in the art upon the reading and understanding of this specification.
Number | Date | Country | Kind |
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1930094-6 | Mar 2019 | SE | national |
1930095-3 | Mar 2019 | SE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/US2020/024553 | 3/25/2020 | WO | 00 |