WO2024124371A1

WO2024124371A1 - Mechanism and procedure for discovering ue pose of xr service on ran side

Info

Publication number: WO2024124371A1
Application number: PCT/CN2022/138347
Authority: WO
Inventors: Yonggang Wang; Tao Tao
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2022-12-12
Filing date: 2022-12-12
Publication date: 2024-06-20

Abstract

Various example embodiments relate to devices, methods, apparatuses and computer readable media for discovering pose of user equipment of an extended reality service on a radio access network side. A terminal device may comprise at least one processor and at least one memory storing instructions. The instructions, when executed by the at least one processor, may cause the terminal device at least to register a tracking source device for a service with a network device. The tracking source device may be selected from a server providing the service, the terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.

Description

MECHANISM AND PROCEDURE FOR DISCOVERING UE POSE OF XR SERVICE ON RAN SIDE

TECHNICAL FIELD

Various example embodiments described herein generally relate to communication technologies, and more particularly, to devices, methods, apparatuses and computer readable media for discovering pose of user equipment (UE) of an extended reality (XR) service on a radio access network (RAN) side.

BACKGROUND

Certain abbreviations that may be found in the description and/or in the figures are herewith defined as follows:

3GPP Third Generation Partnership Project

AR Augmented Reality

CN Core Network

eMBB Enhanced Mobile Broadband

gNB next Generation Node-B

HMD Head Mounted Display

LMF Location Management Function

MR Mixed Reality

NR New Radio

PDU Protocol Data Unit

RAN Radio Access Network

RRC Radio Resource Control

SPS Semi-Persistent Scheduling

UPF User Plane Function

URLLC Ultra Reliable Low Latency Communications

VR Virtual Reality

XR eXtended Reality

5G system has been designed to efficiently support high data rate eMBB (enhanced mobile broadband) services and high reliability and low latency URLLC (ultra-reliable low latency communication) services. Extended reality (XR) , which refers to various real and virtual combined environments and interactions generated by computer technologies including for example augmented reality (AR) , mixed reality (MR) and virtual reality (VR) , is a mixture of both eMBB and URLLC features with omni-present high data rate as well as high reliability low latency requirements.

SUMMARY

A brief summary of exemplary embodiments is provided below to provide basic understanding of some aspects of various embodiments. It should be noted that this summary is not intended to identify key features of essential elements or define scopes of the embodiments, and its sole purpose is to introduce some concepts in a simplified form as a preamble for a more detailed description provided below.

In a first aspect, an example embodiment of a terminal device is provided. The terminal device may comprise at least one processor and at least one memory storing instructions. The instructions may, when executed by the at least one processor, cause the terminal device at least to register a tracking source device for a service with a network device. The tracking source device may be selected from a server providing the service, the terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.

In a second aspect, an example embodiment of a network device is provided. The network device may comprise at least one processor and at least one memory storing instructions. The instructions may, when executed by the at least one processor, cause the network device at least to receive, from a terminal device receiving a service, registration of a tracking source device for the service, send to the tracking source device a request for tracking information of the terminal device, and receive, from the tracking source device, the tracking information of the terminal device. The tracking information may comprise pose information of the terminal device and an indication of the service received by the terminal device.

In a third aspect, an example embodiment of a tracking source device is provided. The tracking source device may comprise at least one processor and at least one memory storing instructions. The instructions may, when executed by the at least one processor, cause the tracking source device at least to receive from a network device a request for tracking information of a terminal device receiving a service, and send to the network device the tracking information of the terminal device. The tracking information may comprise pose information of the terminal device and an indication of the service received by the terminal device.

In a fourth aspect, an example embodiment of a method is provided. The method may comprise registering a tracking source device for a service with a network device. The tracking source device may be selected from a server providing the service, a terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.

In a fifth aspect, an example embodiment of a method is provided. The method may comprise receiving at a network device from a terminal device receiving a service registration of a tracking source device for the service, sending to the tracking source device a request for tracking information of the terminal device, and receiving from the tracking source device the tracking information of the terminal device. The tracking information may comprise pose information of the terminal device and an indication of the service received by the terminal device.

In a sixth aspect, an example embodiment of a method is provided. The method may comprise receiving, at a tracking source device from a network device, a request for tracking information of a terminal device receiving a service, and sending to the network device the tracking information of the terminal device. The tracking information may comprise pose information of the terminal device and an indication of the service received by the terminal device.

In a seventh aspect, an example embodiment of an apparatus is provided. The apparatus may comprise means for registering a tracking source device for a service with a network device. The tracking source device may be selected from a server providing the service, a terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.

In an eighth aspect, an example embodiment of an apparatus is provided. The apparatus may comprise means for receiving, at a network device from a terminal device receiving a service, registration of a tracking source device for the service, means for sending to the tracking source device a request for tracking information of the terminal device, and means for receiving from the tracking source device the tracking information of the terminal device. The tracking information may comprise pose information of the terminal device and an indication of the service received by the terminal device.

In a ninth aspect, an example embodiment of an apparatus is provided. The apparatus may comprise means for receiving, at a tracking source device from a network device, a request for tracking information of a terminal device receiving a service, and means for sending to the network device the tracking information of the terminal device. The tracking information may comprise pose information of the terminal device and an indication of the service received by the terminal device.

In a tenth aspect, an example embodiment of a computer readable medium is provided. The computer readable medium may comprise instructions which may, when executed by an apparatus, cause the apparatus at least to register a tracking source device for a service with a network device. The tracking source device may be selected from a server providing the service, a terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.

In an eleventh aspect, an example embodiment of a computer readable medium is provided. The computer readable medium may comprise instructions which may, when executed by an apparatus, cause the apparatus at least to receive, at a network device from a terminal device receiving a service, registration of a tracking source device for the service, send to the tracking source device a request for tracking information of the terminal device, and receive from the tracking source device the tracking information of the terminal device. The tracking information may comprise pose information of the terminal device and an indication of the service received by the terminal device.

In a twelfth aspect, an example embodiment of a computer readable medium is provided. The computer readable medium may comprise instructions which may, when executed by an apparatus, cause the apparatus at least to receive at a tracking source device from a network device a request for tracking information of a terminal device receiving a service, and send to the network device the tracking information of the terminal device. The tracking information may comprise pose information of the terminal device and an indication of the service received by the terminal device.

Other features and advantages of the example embodiments of the present disclosure will also be apparent from the following description of specific embodiments when read in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of example embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Some example embodiments will now be described, by way of non-limiting examples, with reference to the accompanying drawings.

Fig. 1A is a schematic diagram illustrating downlink video frame transmissions of an extended reality (XR) service.

Fig. 1B is a schematic diagram illustrating downlink video frame transmissions of an XR service.

Fig. 2 is a schematic diagram illustrating a communication system in which example embodiments of the present disclosure may be implemented.

Fig. 3 is a schematic message sequence chart illustrating a procedure according to an example embodiment of the present disclosure.

Fig. 4 is a schematic message sequence chart illustrating a procedure according to an example embodiment of the present disclosure.

Fig. 5 is a schematic flowchart illustrating a method according to an example embodiment of the present disclosure.

Fig. 6 is a schematic flowchart illustrating a method according to an example embodiment of the present disclosure.

Fig. 7 is a schematic flowchart illustrating a method according to an example embodiment of the present disclosure.

Fig. 8 is a schematic block diagram illustrating an apparatus according to an example embodiment of the present disclosure.

Fig. 9 is a schematic block diagram illustrating an apparatus according to an example embodiment of the present disclosure.

Fig. 10 is a schematic block diagram illustrating an apparatus according to an example embodiment of the present disclosure.

Fig. 11A is a schematic block diagram illustrating devices in a communication network according to an example embodiment of the present disclosure.

Fig. 11B is a schematic block diagram illustrating a tracking source device according to an example embodiment of the present disclosure.

Throughout the drawings, same or similar reference numbers indicate same or similar elements. A repetitive description on the same elements would be omitted.

DETAILED DESCRIPTION

Herein below, some example embodiments are described in detail with reference to the accompanying drawings. The following description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known circuits, techniques and components are shown in block diagram form to avoid obscuring the described concepts and features.

As used herein, the term “network device” may refer to a radio access network (RAN) device or a core network (CN) device. The RAN device may refer to any suitable entities or devices that can provide cells or coverage, through which the terminal device can access the network or receive services. The network device may be commonly referred to as a base station. The term “base station” used herein can represent a node B (NodeB or NB) , an evolved node B (eNodeB or eNB) , a next generation eNB (ng-eNB) , a gNB, or a beyond 5G base station. The base station may be embodied as a macro base station, a relay node, or a low power node such as a pico base station or a femto base station. The base station may consist of several distributed network units, such as a central unit (CU) , one or more distributed units (DUs) , one or more remote radio heads (RRHs) or remote radio units (RRUs) . The number and functions of these distributed units depend on the selected split RAN architecture. The CN device may refer to functions and nodes implemented in LTE (Long Term Evolution) core network (also known as Evolved Packet Core, EPC) , or functions and nodes implemented in 5G core network (5GC) . Examples of functions and nodes implemented in EPC may include but not limited to Mobility Management Entity (MME) , Home Subscriber Server (HSS) , Serving Gateway (SGW) , PDN (Packet Data Network) Gateway (PGW) and other functions and nodes specified in 3GPP specifications. Examples of functions and nodes implemented in 5GC may include but not limited to Access and Mobility Management Function (AMF) , Session Management Function (SMF) , Location Management Function (LMF) , User Plane Function (UPF) , and other functions and nodes specified in 3GPP specifications. In some example embodiments, the network device may further comprise devices deployed in a data network e.g. the internet, examples of which may include application servers that provide various services such as XR services to users.

As used herein, the term “terminal device” or “user equipment” (UE) refers to any entities or devices that can wirelessly communicate with the network devices or with each other. Examples of the terminal device can include a mobile phone, a mobile terminal, a mobile station, a subscriber station, a portable subscriber station, an access terminal, a computer, a wearable device, a head mounted device (HDM) , an on-vehicle communication device, a machine type communication (MTC) device, an internet of things (IoT) device, an internet of everything (IoE) device, a device-to-device (D2D) communication device, a vehicle to everything (V2X) communication device, a sensor and the like. The term “terminal device” can be used interchangeably with UE, a user terminal, a mobile terminal, a mobile station, or a wireless device.

3GPP has studied use cases and deployment scenarios of XR applications and evaluated achievable performance of XR traffic modelling in the 5G system during the Rel-17 XR study item (SI) phase. The characteristics of XR traffic and challenges are summarized below:

· high data rate, data rate up to 60 Mbps;

· low latency, latency up to 10 ms;

· high reliability, reliability up to 10 ^-4; and

· high power consumption.

An essential element in XR applications is the use of positional tracking, i.e. the process of tracing the XR scene coordinates of moving objects in real-time, such as head mounted devices (HMDs) or motion controller peripherals. The positional tracking allows to derive the XR viewer’s pose, i.e. a combination of position and orientation of the viewer, and motion consisting of a sequence of poses, based on which content is rendered to simulate a view of virtual scene. The contents of the viewer are not limited to head mounted device, but also include glasses, bodies, limbs, and extended objects, such as weapons. The positional tracking adds the concept of continuous localization over time.

The positional tracking can be performed in two typical ways, i.e. outside-in tracking and inside-out tracking. The outside-in tracking is a method of optical tracking where tracking sensors, for example monocular, stereo and/or depth cameras, may be placed in a stationary location and oriented towards the tracked object to take pictures of the tracked object. Image recognition algorithms may be applied to determine pose of the tracked object. On the contrary, the inside-out tracking refers to a process where tracking sensors are located on the device being tracked, and the pose of the device being tracked is derived from output of the sensors. Multiple sensors such as camera, proximity sensor, inertial measurement unit (IMU) , gyroscope, radio beacon and other sensors may be used in combination to get a better localization accuracy.

The pose of the tracked device (i.e., the pose of the XR viewer) is reported to an application server which provides the XR service, and the XR application server would transmit 3D video/audio flow to XR user equipment (UE) e.g. the HMD based on the received pose of the XR viewer. Figs. 1A and 1B illustrates relationship between the uplink (UL) pose frames and downlink (DL) video/audio frames (hereinafter referred to as “video frame” for convenience) . The rate of UL pose frames is usually higher than the rate of DL video frames. In the examples shown in Figs. 1A and 1B, the rate of UL pose frames is 250 Hz, which is about 4 times of the rate 60 Hz of DL video frames.

Referring to Fig. 1A, the DL video frames may include an intra frame (I-frame) and a number of predictive frames (P-frames, only one is shown) within a group of pictures (GOP) . The I-frame, which is usually the first frame in the GOP, represents a key frame which can be decoded without reference to other frames because it contains a complete picture. The P-frame represents difference between this frame and the previous I-frame or P-frame, and it is decoded by superimposing the difference onto the previously decoded picture to obtain the final picture. The GOP may further include a bidirectional frame (B-frame, not shown) , of which decoding refers to frames that occur both before and after it. For convenience of description, the B-frame is not shown in Figs. 1A-1B, but it would be appreciated that description relating to the P-frame here is also applicable to the B-frame.

As shown in Fig. 1A, since the rate of UL pose frames is 4 times of the rate of DL video frames, it is possible to capture 4 different head positions if the XR viewer’s head moves fast. The high sample rate of the pose frames helps to obtain the accurate pose of the XR viewer, and it can also ensure reliability of the uplink transmissions. The P-frame is encoded based on the I-frame in the GOP and the vision (or picture) related to the latest received pose in the pose frame, e.g. the pose frame #4 in the example shown in Fig. 1A taking into consideration of the transmission and encoder delay. The P-frame may have a size depending on the vision difference between the pose corresponding to the I-frame and the latest pose. Generally, the size of the P-frame varies between 20%and 50%of the size of the I-frame.

If the XR viewer’s pose changes greatly, the next picture could be very different from the I-frame, and it may be encoded as a second I-frame adopting intra-frame prediction, as shown in Fig. 1B, even it is in the middle of the GOP for example in the video encoding format H. 264 and H. 265. At this time, the amount of DL transmission of the XR service will increase doubly as compared with the P-frame (Fig. 1A) , and the required radio resources will also reach the maximum.

The XR traffic flow is also observed to be quasi-periodic in the sense that the arrival time of the video frames is varying from the expected time due to rendering, encoding, packet segmentation as well as core network processing of the traffic flow. The arrival time varying is also referred to as jitter, which may be in a certain range for example from -4 ms to +4 ms. Due to the non-negligible jitter and the quite large size of the DL video frames, conventional semi-persistent scheduling (SPS) is not directly applicable for XR applications. For example, if one or more video frames arrive too early before an SPS occasion, the frames have to be delayed until the SPS occasion, which would increase the latency of the traffic flow and negatively affect the radio access network (RAN) performance given the tight propagation delay budget (PDB) in downlinks of e.g. 10 ms. On the other hand, if one or more video frames arrive later than a starting symbol of an SPS occasion or the network has no time to process the frames, the frames will miss the SPS occasion.

3GPP has discussed SPS enhancement to match the XR traffic characteristics. The possible SPS enhancement may include for example multiple SPS configurations and SPS combined with dynamic scheduling. For example, two or more SPS configurations may be configured for the XR traffic flow, and the two or more SPS configurations may have the same periodicity matching the XR traffic flow but different offset/timing. When a DL video frame arrives, it may be transmitted on one or more subsequent SPS occasions. The SPS combined with dynamic scheduling is to configure one SPS configuration for the XR traffic flow, and if a DL video frame does not arrive before a corresponding SPS occasion, the network may force the XR user equipment (UE) e.g. the HMD into an "ON-duration" mode by transmitting a discontinuous reception (DRX) command MAC CE. During the ON-duration period, the XR UE would keep monitoring a physical downlink control channel (PDCCH) to receive the belated DL video frame on a physical downlink shared channel (PDSCH) .

It is evident that payloads coming with the XR service are quite large. For example, if the average XR data rate is 45 Mbps with 60 fps, the average payload size per video frame would be around 750 kbits, which is a great burden for the air interface transmission. It is important to reserve sufficient radio resources for multiple SPS configurations for the XR traffic flow. On the other hand, XR applications may use adaptive encoding schemes where the XR data rate may change a lot from time to time. If the radio resources are reserved at the maximum data rate and activated at all times, it is a waste of air interface resources.

An approach to reduce the resource waste is to predict the size of the next arriving frame (i.e., the future frame) and deactivate or activate partial SPS configurations based on the future frame size prediction. For example, if the future frame is small, partial SPS configurations may be deactivated, and the released resources may be used for other transmissions to achieve resource utilization efficiency and network capacity improvements. The future frame size prediction may be performed using algorithms such as linear regression prediction, Markov prediction, neural network or other mathematical models. However, the future frame size prediction algorithms are based on the continuous regularity of development of objects in the previous frames. If there is a large change in the outside world, such as a large excitation input, the prediction often has a large deviation from the actual future frame. For example, in XR applications, the viewer’s pose change will directly affect the visual field and thus the encoded size of subsequent frames, which may lead to a large deviation between the predicted future frame size and the actual future frame size. Therefore, how to reserve resources for the XR traffic flow is still a problem.

Hereinafter, example embodiments of a mechanism and procedure for discovering UE pose of XR service on the radio access network (RAN) side will be described in detail with reference to the accompanying drawings. As mentioned above, the XR applications may use adaptive encoding schemes where the XR data rate may change according to not only the previous vision but also the viewer’s pose change, so that the discovering of the UE pose on the RAN side can help the RAN device e.g., the base station to evaluate the accurate traffic of the XR service. With the knowledge of the UE pose, the RAN device can apply more accurate algorithms, which consider not only the previous frames but also the viewer’s pose or pose change, to predict size of future frames. The RAN device can optimize the XR service downlink transmissions based on at least the predicted future frame size. Although the example embodiments are described in the context of XR applications/services, it would be appreciated that the example embodiments are also applicable in use cases where the UE receives other services in which the UE pose is taken into consideration.

Fig. 2 illustrates a schematic diagram of a communication system 100 in which example embodiments of the present disclosure may be performed. Referring to Fig. 2, the communication system 100, which may be a part of a larger communication network or system, may include a user equipment (UE) 110, a radio access network (RAN) 120, and a core network (CN) 130.

The UE 110, the RAN 120 and the CN 130 may constitute a cellular communication network e.g. a 5G New Radio (NR) network. The UE 110 may be implemented as an NR-enabled UE, and the RAN 120 may include a base station 122 which provides access to the network for the UE 110. The base station 122 may be implemented as for example a next generation Node-B (gNB) as shown or a next generation eNB (ng-eNB) . The UE 110 may establish a radio resource control (RRC) connection with the base station 122 to receive/transmit data from/to the base station 122. It would be appreciated that the RAN 120 may include a plurality of base stations 122, and each base station 122 may serve a plurality of UEs 110. In some example embodiments, the RAN 120 may also include the plurality of UEs 110.

The CN 130 may be implemented as a 5G core network (5GC) and connected to a plurality of base stations 122 to provide coordination and control for the base stations 122. The CN 130, when implemented as the 5GC, may include for example a location management function (LMF) 132, a user plane function (UPF) 134 and other functions or nodes. The LMF 132 can provide positioning functionality to determine a geographic position of the UE 110 based on downlink and/or uplink radio signal measurements. In an example embodiment, partial location management component (LMC) may be implemented in the RAN 120, e.g. as a component in the base station 122, to provide partial positioning functionality. The UPF 134 can support packet routing and quality of service (QoS) handling, and it can act as a protocol data unit (PDU) session anchor (PSA) point to provide interconnection to a data network (DN) 140.

Although the 5G NR network is described here, it would be appreciated that the example embodiments of the present disclosure are also applicable to other networks, for example an 4G LTE network or a beyond 5G network.

The DN 140, which may be a public data network such as the internet or a private data network such as an enterprise intranet, is connected to the CN 130 via a wireless or wired connection. A plurality of application servers 142 (only one is shown) may be deployed in the DN 140 to provide various services to customers. The application server 142 may be operated by a service provider (SP) such as an entertainment company that provides for example extended reality (XR) service to the customers. For example, the XR application running at the application server 142 may generate video, audio and/or haptic contents representing various real and virtual combined environments and distribute the contents to the customers via the cellular communication network 100. The XR application may also collect from the customers for example real environmental data and/or user interaction data, including for example the user’s pose, which may be used to create the video, audio and/or haptic contents.

The UE 110 may receive the XR service from the application server 142 via the cellular communication network 100, specifically via the core network 130 and the RAN 120. The UE 110 may be implemented as for example a head mounted device (HMD) , XR glasses, an XR cabin, a handheld device or other multimedia devices that include one or more display panels, one or more speakers or earphones, and/or one or more haptic actuators so that it can reproduce a real and virtual combined environment by playing the video, audio and/or haptic contents provided from the XR service. In some example embodiments, the UE 110 may also transmit video, audio, haptic and interaction data to the application server 142. For example, the UE 110 may include one or more cameras, one or more microphones or microphone arrays, one or more haptic sensors and other sensors to capture environmental and interaction data. The UE 110 may also process, for example encode, edit, combine and/or compress, the captured data before transmitting it to the application server 142.

As mentioned above, outside-in tracking or inside-out tracking may be performed to track pose of the UE 110. The UE pose will be reported to the XR application server 142 so that the XR application server 142 can create XR service contents for the user. In the outside-in tracking, a tracking server 150, which may include one or more tracking sensors such as monocular, stereo and/or depth cameras or other suitable sensors, may be placed in a stationary location and oriented towards the UE 110 to capture pose of the UE 110. The tracking server 150 may act as a separate UE connected to the RAN 120 and report the captured pose of the UE 110 to the XR application server 142, or it may act as a component of the UE 110 or connect to the UE 110, and report the captured pose of the UE 110 via the UE 110 to the XR application server 142.

In the inside-out tracking, one or more tracking sensors, which may include for example camera, proximity sensor, inertial measurement unit (IMU) , gyroscope, radio beacon and other sensors, may be disposed on the UE 110 to capture pose of the UE 110. The UE 110 may transmit the captured pose to the XR application server 142.

In example embodiments, the base station 122 may be enabled to be aware of information of instance pose or pose change of the UE 110 so that the base station 122 can evaluate the accurate traffic of the XR service, which may be used to optimize downlink transmission of the XR service. It could provide more efficient resource allocation and scheduling for XR service characteristics and achieve network capacity improvement. In an example embodiment, the UE 110, the tracking server 150 or the XR application server 142 may send pose information of the UE 110 to the base station 122. The pose information may be carried in an application layer message, and the base station 122 may parse the application layer message to obtain the pose information and map the pose information to a certain XR service. In another example embodiment, the UE 110, the tracking server 150 or the XR application server 142 may send the pose information of the UE 110 via an application layer message to a function or node deployed in the CN 130, e.g. the LMF 132 or other functions or nodes. The CN function or node may parse the application layer message to obtain the pose information of the UE 110 and then send the pose information to the base station 120 via a network inner signaling. Unlike the application layer message that is defined in the XR application, the network inner signaling refers to signaling or messages defined in the cellular communication network, examples of which may include RRC signaling, MAC CE, physical layer messages, or other messages interacting between nodes of communication system which are defined in 3GPP specifications. The base station 122 may directly process the network inner signaling without running an XR application to parse it. Therefore, this scheme would not increase complexity of the base station 122.

Fig. 3 is a schematic message sequence chart illustrating a procedure 200 according to an example embodiment of the present disclosure. The procedure 200 may be implemented at a user equipment (UE) like the UE 110, a base station (BS) like the base station 122, a core network (CN) device like the LMF 132, an application server like the XR application server 142, and a tracking server like the tracking server 150. In the procedure 200, the CN device like the LMF 132 would collect pose information of the UE 110 and forward the pose information to the base station 122.

Referring to Fig. 3, at 202, the UE 110 may send a tracking source registration message to the LMF 132 to register a tracking source device for a service with the LMF 132. The service may be for example but not limited to an extended reality (XR) service received at the UE 110, and the tracking source device refers to a device which is aware of pose information of the UE 110 and can send the pose information of the UE 110 to the LMF 132. For example, the tracking source device may be the UE 110 itself if the inside-out tracking scheme is employed, the tracking server 150 if the outside-in tracking scheme is employed, or the XR application server 142 which receives the pose information of the UE 110 from the UE 110 or the tracking server 150. It is assumed that when the XR service is configured for the UE 110, the UE 110 is aware of whether the separate tracking server 150 is configured for tracking pose of the UE 110 and thus the UE 110 is capable of selecting the tracking source device from the UE 110 itself, the tracking server 150, and the XR application server 142.

In an example embodiment, the tracking source registration message may include an indication of the XR service and information of the tracking source device associated with the XR service. The indication of the XR service may comprise for example a service flow identity (ID) such as a quality of service (QoS) flow ID of the XR service, and the information of the tracking source device may comprise an internet protocol (IP) address of the tracking source device. Optionally, the information of the tracking source device may further comprise a communication port of the tracking source device for transmitting the pose information of the UE 110 to the LMF 132.

In an example embodiment, the tracking source registration message may be an application layer message. The LMF 132 may parse the application layer message based on application layer protocols to extract the indication of the XR service e.g. the QoS flow ID and the information of the tracking source device e.g. the IP address and port. It would be appreciated that the LMF 132 may receive the tracking source registration message from a plurality of UEs 110 receiving various XR services. In an example, the LMF 132 may establish a lookup table to store the QoS flow IDs of the XR services and the IP addresses and ports of the tracking source devices associated with the XR services.

At 204, the LMF 132 may send a request for tracking information of the UE 110 to the tracking source device registered in the step 202. The LMF 132 may send the tracking information request in response to the received tracking source registration message. Depending on the tracking source device registered in the step 202, the LMF 132 may send the tracking information request to the XR server 142 at 204a, to the tracking server 150 at 204b, or to the UE 110 at 204c. The tracking information request may also be transmitted via an application layer message. In an example, the tracking information request may include information of the UE 110 of which the tracking information is requested, and the indication of the XR service received at the UE 110. In an example, when the UE 110 is registered as the tracking source device, the UE 110 can report the pose information and the XR service associated with the pose information to the LMF 132 when the XR service starts.

During the XR service, the UE 110 may receive downlink (DL) service flow from the XR application server 142 at 206a. If the inside-out tracking scheme is employed, the UE 110 may also send uplink (UL) tracking information for example pose frames to the XR application server 142 at 206a. On the other hand, if the outside-in tracking scheme is employed, the tracking server 150 may send the UL tracking information for example the pose frames to the XR application server 142 at 206b. The UE 110 or the tracking server 150 may determine six degrees of freedom (6DoFs) parameters of the UE 110 based on inputs of various sensors deployed at the UE 110 or the tracking server 150. If one or more cameras are used at the UE 110 or the tracking server 150, image recognition algorithms or neural network models may be applied to determine the 6DoFs parameters of the UE 110. The UE 110 or the tracking server 150 may encode the 6DoFs parameters in the pose frame and send it to the XR application server 142. In an example embodiment, the UE 110 or the tracking server 150 may calculate the pose change of the UE 110 (i.e., differences of the 6DoFs parameters between adjacent frames) and report the pose change of the UE 110 to the XR application server 142.

At 208, the tracking source device may send the tracking information of the UE 110 to the LMF 132. In response to the tracking information request received from the LMF 132 at 204a, 204b or 204c, the XR application server 142, the tracking server 150 or the UE 110 may send the tracking information to the LMF 132 at 208a, 208b or 208c. As discussed above, the tracking information may comprise pose or pose change of the UE 110. The tracking information may further comprise the indication, e.g. the QoS flow ID, of the XR service received at the UE 110. In an example embodiment, the tracking source device may send the tracking information to the LMF 132 in a frequency of the UL pose frame reporting from the UE 110 or the tracking server 150 to the XR application server 142.

The tracking information may be transmitted to the LMF 132 via an application layer message at the step 208. Then the LMF 132 may parse the application layer message to determine the pose information of the UE 110 at 210. Based on the tracking information received at the step 208, the LMF 132 may determine pose or pose change of the UE 110, and the XR service received at the UE 110. In an example, the LMF 132 may record the received 6DoFs pose parameters in the time series and calculate the 6DoFs pose parameters change of the UE 110. In another example, the tracking information received at the step 208 may already contain the pose change of the UE 110.

At 212, the LMF 132 may send the determined pose information, which may comprise the pose or pose change of the UE 110, to the base station 122 serving the UE 110. The LMF 132 may send the pose information to the base station 122 in the frequency of the UL pose frame reporting from the UE 110 or the tracking server 150 to the XR application server 142, so that the base station 122 can be aware of the accurate pose or pose change of the UE 110. In an example, the pose information may further comprise the indication (e.g., the QoS flow ID) of the XR service received at the UE 110. Unlike the application layer messages transmitted in the steps 202 to 208, the LMF 132 may send the pose information via a network inner signaling. As discussed above, the network inner signaling refers to signaling or messages defined in the cellular communication network, examples of which may include RRC signaling, MAC CE, physical layer messages, or other messages interacting between nodes of communication system which are defined in 3GPP specifications. In an example, the LMF 132 may send the pose information via an NR Positioning Protocol A (NRPPa) message to the base station 122. NRPPa is a protocol defined by 3GPP for positioning information exchange between the RAN 120 and the LMF 132. In the example embodiment, since the base station 122 does not need to parse an application layer message, it can reduce complexity of the base station 122.

At 214, the base station 122 may predict size of a next downlink frame of the XR service based on at least the pose information of the UE 110. When the XR service is configured, the CN 130 would inform the base station 122, in a similar way as time sensitive communication assistance information (TSCAI) , about the traffic pattern of the XR service, for example XR frame periodicity, I/P-frame pattern and I/P-frame size statistics (e.g., maximum or medium size) . The base station 122 can learn from the traffic pattern whether the next frame is an I-frame or a P-frame. If the next frame is the I-frame, the base station 122 may determine that it would have the maximum size. If the next frame is the P-frame, the base station 122 may run an algorithm such as linear regression prediction, Markov prediction, neural network or other mathematical models to predict the size of the next frame. The algorithm would take the previous downlink frames, the pose information (pose or pose change) and optionally other factors as inputs. As discussed above, the pose information of the UE 110 can help the base station 122 to evaluate the accurate size of the next XR service frame.

At 216, the base station 122 may optimize radio resource configuration for downlink transmissions of the XR service based on at least the predicted size of the next frame of the XR service. For example, the base station 122 may re-arrange the radio resources or change some radio resource configurations for the purpose of providing more efficient resource allocation for the XR traffic flow.

In an example embodiment where multiple semi-persistent scheduling (SPS) configurations are configured for the XR service, if the UE 110 has a dramatical pose change and thus the predicted next frame size is large, the base station 122 may activate more SPS configurations for transmission of the next frame. It would increase PDSCH (physical downlink shared channel) transmission occasions provided by the SPS configurations in a period. In an example embodiment, since the large frame would incur a large processing delay, the SPS configurations may be shifted a certain period to accommodate the large delay. On the other hand, if the UE 110 has a small pose change and thus the predicted next frame size is small, the base station 122 may deactivate one or more SPS configurations and release these radio resources for other services in advance.

In an example embodiment where dynamic scheduling is employed for the XR service, if the UE 110 has a dramatical pose change and thus the predicted next frame size is large, the delay would be large because the large frame requires more encoding time. Then the base station 122 may send an instruction to the UE 110 to enable PDCCH (physical downlink control channel) skipping for a certain period when the UE 110 wakes up in the discontinuous reception (DRX) cycle so that the UE 110 will monitor the PDCCH after the certain period. It can cancel out the increasing delay and avoid ineffective PDCCH monitoring, thereby saving power consumption of the UE 110. On the other hand, if the UE 110 has a small pose change and thus the predicted next frame size is small, the base station 122 may send an instruction to the UE 110 to reduce the inactive timer after the ON-duration because the delay would be small.

Here some examples of the XR downlink transmission optimization have been described, but it would be appreciated that, depending on the SPS enhancement schemes employed for the XR traffic flow, other optimization solutions are also conceivable. With the accurate next frame size prediction, the base station 122 can reserve and allocate an appropriate amount of radio resources for the XR service traffic flow, and the saved radio resources may be allocated to other services, thereby achieving resource utilization efficiency and network capacity improvements.

Fig. 4 is a schematic message sequence chart illustrating a procedure 300 according to an example embodiment of the present disclosure. The procedure 300 may be implemented at a user equipment (UE) like the UE 110, a base station (BS) like the base station 122, an application server like the XR application server 142, and a tracking server like the tracking server 150. Unlike the procedure 200 where the CN device e.g. the LMF 132 collects pose information of the UE 110 and provides the collected pose information to the base station 122, in the procedure 300 the base station 122 can directly collect the pose information of the UE 110 from the tracking source device. It can reduce complexity of the CN device e.g. the LMF 132 and reduce at least the signaling between the LMF 132 and the base station 122. Since steps in the procedure 300 are similar to those in the procedure 200, the procedure 300 will be described briefly here and details thereof may refer to the procedure 200 discussed above.

Referring to Fig. 4, at 302, the UE 110 may register a tracking source device for a service with the base station 122 by sending a tracking source registration message to the base station 122. The service may be for example but not limited to an extended reality (XR) service received at the UE 110, and the tracking source device may be selected from for example the UE 110 if the inside-out tracking scheme is employed, the tracking server 150 if the outside-in tracking scheme is employed, or the XR application server 142 which receives the pose information of the UE 110 from the UE 110 or the tracking server 150. The tracking source registration message may be an application layer message and it may include an indication of the XR service and information of the tracking source device associated with the XR service. The indication of the XR service may comprise for example a service flow identity (ID) such as a quality of service (QoS) flow ID of the XR service, and the information of the tracking source device may comprise an internet protocol (IP) address of the tracking source device. Optionally, the information of the tracking source device may further comprise a communication port of the tracking source device for transmitting the pose information of the UE 110 to the base station 122. The base station 122 may parse the application layer message based on application layer protocols and extract the indication of the XR service e.g. the QoS flow ID and the information of the tracking source device e.g. the IP address and port. It would be appreciated that the base station 122 may receive the tracking source registration message from a plurality of UEs 110 receiving various XR services. In an example, the base station 122 may establish a lookup table to store the QoS flow IDs of the XR services and the IP addresses and ports of the tracking source devices associated with the XR services.

At 304, the base station 122 may send a request for tracking information of the UE 110 to the tracking source device registered in the step 302. Depending on the tracking source device registered in the step 302, the base station 122 may send the tracking information request to the XR server 142 at 304a, to the tracking server 150 at 304b, or to the UE 110 at 304c. The tracking information request may also be transmitted via an application layer message and it may include information of the UE 110 of which the tracking information is requested, and the indication of the XR service received at the UE 110. In an example, when the UE 110 is registered as the tracking source device, the UE 110 can report the pose information and the XR service associated with the pose information to the base station 122 when the XR service starts.

During the XR service, the UE 110 may receive downlink (DL) service flow from the XR application server 142 at 306a. If the inside-out tracking scheme is employed, the UE 110 may also send uplink (UL) tracking information for example pose frames to the XR application server 142 at 306a. On the other hand, if the outside-in tracking scheme is employed, the tracking server 150 may send the UL tracking information for example the pose frames to the XR application server 142 at 306b. In an example embodiment, the pose frames may indicate pose or pose change of the UE 110.

At 308, the tracking source device may send the tracking information of the UE 110 to the base station 122. In response to the tracking information request received from the base station 122 at 304a, 304b or 304c, the XR application server 142, the tracking server 150 or the UE 110 may send the tracking information to the base station 122 at 308a, 308b or 308c. As discussed above, the tracking information may comprise pose or pose change of the UE 110. The tracking information may further comprise the indication, e.g. the QoS flow ID, of the XR service received at the UE 110. In an example embodiment, the tracking source device may send the tracking information to the base station 122 in a frequency of the UL pose frame reporting from the UE 110 or the tracking server 150 to the XR application server 142, so that the base station 122 can be aware of accurate pose or pose change of the UE 110.

The tracking information may be transmitted to the base station 122 via an application layer message at the step 308. Then the base station 122 may parse the application layer message to determine the pose information of the UE 110 at 310. Based on the tracking information received at the step 308, the base station 122 may determine pose or pose change of the UE 110, and the XR service associated with the UE 110. In an example, the base station 122 may calculate the pose change of the UE 110 based on the tracking information received at the step 308. In another example, the tracking information received at the step 308 may already contain the pose change of the UE 110.

At 314, the base station 122 may predict size of a next downlink frame of the XR service based on at least the pose information (pose or pose change) of the UE 110. If the next frame is the I-frame, the base station 122 may determine that it would have the maximum size. If the next frame is the P-frame, the base station 122 may run an algorithm such as linear regression prediction, Markov prediction, neural network or other mathematical models to predict the size of the next frame. The algorithm would take the previous downlink frames, the pose information and optionally other factors as inputs. As discussed above, the pose information of the UE 110 can help the base station 122 to evaluate the accurate size of the next XR service frame.

At 316, the base station 122 may optimize radio resource configuration for downlink transmissions of the XR service based on at least the predicted size of the next frame of the XR service. For example, the base station 122 may re-arrange the radio resources or change some radio resource configurations for the purpose of providing more efficient resource allocation for the XR traffic flow. The XR transmission optimization may be similar to those discussed above with respect to the step 216, and a repetitive description thereof is omitted here. With the accurate next frame size prediction, the base station 122 can reserve and allocate an appropriate amount of radio resources for the XR service traffic flow, and the saved radio resources may be allocated to other services, thereby achieving resource utilization efficiency and network capacity improvements.

Fig. 5 is a schematic flowchart illustrating a method 400 according to an example embodiment of the present disclosure. The method 400 may be performed at a terminal device like the UE 110 discussed above. Since steps of the method 400 have been discussed above with reference to the

procedures

200, 300, the method 400 will be described briefly here.

Referring to Fig. 5, at 402, the UE 110 may register a tracking source device for a service with a network device. The tracking source device may be selected from for example the application server 142 providing the service, the UE 110 receiving the service, or the tracking server 150 configured to track pose of the UE 110. In an example, the UE 110 may indicate an IP address and port of the tracking source device and a QoS flow ID of the service to the network device in the step 402.

In an example embodiment, the service provided by the application server 142 may be an extended reality (XR) service. The UE 110 may be configured to receive the XR service.

In an example embodiment, the network device may be a CN device e.g. the LMF 132 or a RAN device e.g. the base station 122. For convenience of description, herein the network device is denoted by a reference numeral “160” .

If the UE 110 is registered with the network device 160 as the tracking source device for the service (i.e., inside-out tracking) , the UE 110 may further receive a request for tracking information from the network device 160 at 404. The network device 160 may transmit the tracking information request in response to the tracking source registration message received at 402.

At 406, the UE 110 may send tracking information to the network device 160. In an example, the UE 110 may send the tracking information in response to the tracking information request received at the step 404. The tracking information may comprise pose information of the UE 110 and an indication of the service received at the UE 110, e.g., the QoS flow ID of the service.

In an example embodiment, the UE 110 may send the tracking information via an application layer message to the network device 160.

Fig. 6 is a schematic flowchart illustrating a method 500 according to an example embodiment of the present disclosure. The method 500 may be performed at a network device 160, for example a CN device such as the LMF 132 discussed above or a RAN device such as the base station 122 discussed above. Since steps of the method 500 have been discussed above with reference to the

procedures

200, 300, the method 500 will be described briefly here.

Referring to Fig. 6, at 502, the network device 160 may receive registration of a tracking source device for the service from the UE 110. The UE 110 may be configured to receive the service. In an example, the service may be an extended reality (XR) service provided from the application server 142. The tracking source device may be selected from for example the application server 142 providing the service, the UE 110 receiving the service, or the tracking server 150 configured to track pose of the UE 110. In an example, the network device 160 may receive the registration of the tracking source device via an application layer message, and the network device 160 may parse the application layer message to extract information of the tracking source device and an indication of the service associated with the tracking source device.

At 504, the network device 160 may send a request for tracking information of the UE 110 to the registered tracking source device. The request may also be carried via an application layer message.

At 506, the network device 160 may receive the tracking information of the UE 110 from the tracking source device. The tracking information may comprise pose information of the UE 110 and an indication of the service received by the UE 110. The network device 160 may receive the tracking information via an application layer message.

If the network device 160 is implemented as a CN device like the LMF 132, the LMF 132 may further determine pose information of the UE 110 based on the received tracking information at 507, and inform the base station 122 serving the UE 110 of the pose information of the UE 110. In an example embodiment, the determined pose information may include pose or pose change of the UE 110. The LMF 132 may send the pose information of the UE 110 to the base station 122 via a network inner signaling.

If the network device 160 is implemented as a radio access network device like the base station 122, the base station 122 may further determine pose information of the UE 110 based on the received tracking information at 508 and predict size of a next frame of the service based on at least the determined pose information of the UE 110 at 510. In an example embodiment, the determined pose information may include pose or pose change of the UE 110. At 512, the base station 122 may optimize radio resource configuration for transmission of the service based on the predicted size of the next frame of the service.

Fig. 7 is a schematic flowchart illustrating a method 600 according to an example embodiment of the present disclosure. The method 600 may be performed at a tracking source device which is aware of the pose of a UE receiving a service. For convenience of description, the tracking source device is denoted by a reference numeral “170” . As discussed above, the tracking source device 170 may be selected from for example the application server 142 providing the service, the UE 110 receiving the service, or the tracking server 150 configured to track the pose of the UE 110. Since steps of the method 600 have been discussed above with reference to the

procedures

200, 300, the method 600 will be described briefly here.

Referring to Fig. 7, the tracking source device 170 may receive a request for tracking information of the UE 110 from a network device 160 at 602, and send to the network device 160 the tracking information of the UE 110 at 604. The tracking information may comprise pose information of the UE 110 and an indication of the service received at the UE 110.

In an example embodiment, the network device 160 may be for example a CN device such as the LMF 132 associated with the UE 110, or a RAN device such as the base station 122 serving the UE 110.

In an example embodiment, the indication of the service received at the UE 110 may comprise a QoS flow ID of the service. The tracking source device 170 may receive the QoS flow ID of the service in the tracking information request.

In an example embodiment, the tracking source device 170 may send the tracking information of the UE 110 to the network device 160 via an application layer message.

In an example embodiment, the service received at the UE 110 may be an extended reality (XR) service.

Fig. 8 is a schematic block diagram illustrating an apparatus 700 according to an example embodiment of the present disclosure. The apparatus 700 may be implemented to comprise or to form at least a part of the UE 110 so as to perform operations of the UE 110. Since the operations of the UE 110 have been discussed above with reference to Figs. 1A-7, the blocks of the apparatus 700 will be described briefly here and details thereof may refer to the above description.

Referring to Fig. 8, the apparatus 700 may comprise a first means 702 for registering a tracking source device for a service with a network device. The tracking source device may be selected from a server providing the service, a terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.

In an example embodiment, the terminal device is registered as the tracking source device for the service, and the apparatus 700 may further comprise a second means 704 for receiving a request for tracking information from the network device, and a third means 706 for sending tracking information to the network device. The tracking information may comprise pose information of the terminal device and an indication of the service received by the terminal device.

In an example embodiment, the tracking information may be sent via an application layer message.

In an example embodiment, the network device may comprise a radio access network device or a core network device.

In an example embodiment, the service may be an extended reality service.

Fig. 9 is a schematic block diagram illustrating an apparatus 800 according to an example embodiment of the present disclosure. The apparatus 800 may be implemented to comprise or to form at least a part of the network device 160 so as to perform operations of the network device 160 discussed above. Since the operations of the network device 160 have been discussed above with reference to Figs. 1A-7, the blocks of the apparatus 800 will be described briefly here and details thereof may refer to the above description.

Referring to Fig. 9, the apparatus 800 may comprise a first means 802 for receiving, at the network device 160 from a terminal device receiving a service, registration of a tracking source device for the service, a second means 804 for sending, to the tracking source device, a request for tracking information of the terminal device, and a third means 806 for receiving, from the tracking source device, the tracking information of the terminal device. The tracking information may comprise pose information of the terminal device and an indication of the service received by the terminal device.

In an example embodiment, the network device 160 may be a core network device. The apparatus 800 may further comprise a fourth means 807 for determining pose information of the terminal device based on the received tracking information, and a fifth means 809 for informing a radio access network device serving the terminal device of the pose information of the terminal device.

In an example embodiment, the core network device may receive the tracking information via an application layer message and informs the pose information of the terminal device to the radio access network device via a network inner signaling.

In an example embodiment, the network device 160 may be a radio access network device. The apparatus 800 may further comprise a sixth means 808 for determining pose information of the terminal device based on the received tracking information, a seventh means 810 for predicting size of a next frame of the service based on at least the pose information of the terminal device, and an eighth means 812 for optimizing radio resource configuration for transmission of the service based on the predicted size of the next frame of the service.

In an example embodiment, the pose information of the terminal device may indicate at least one of the following: pose of the terminal device, or pose change of the terminal device.

In an example embodiment, the tracking source device may be selected from a server providing the service, the terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.

In an example embodiment, the service may be an extended reality (XR) service.

Fig. 10 is a schematic block diagram illustrating an apparatus 900 according to an example embodiment of the present disclosure. The apparatus 900 may be implemented to comprise or to form at least a part of tracking source device 170 so as to perform operations of the tracking source device 170 discussed above. Since the operations of the tracking source device 170 have been discussed above with reference to Figs. 1A-7, the blocks of the apparatus 900 will be described briefly here and details thereof may refer to the above description.

Referring to Fig. 10, the apparatus 900 may comprise a first means 902 for receiving, at the tracking source device 170 from a network device, a request for tracking information of a terminal device receiving a service, and a second means 904 for sending, to the network device, the tracking information of the terminal device. The tracking information may comprise pose information of the terminal device and an indication of the service received by the terminal device.

In an example embodiment, the indication of the service received by the terminal device may comprise a QoS flow ID of the service. The tracking source device 170 may receive the QoS flow ID of the service in the tracking information request.

In an example embodiment, the tracking source device 170 may comprise a server providing the service, the terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.

In an example embodiment, the tracking information of the terminal device may be sent to the network device via an application layer message.

In an example embodiment, the service may be an XR service.

Fig. 11A is a schematic block diagram illustrating devices in a communication network 1000 according to an example embodiment of the present disclosure. As shown in Fig. 11A, the communication network 1000 may comprise a terminal device 1010 which may be implemented as the UE 110 discussed above, a RAN device 1020 which may be implemented as the base stations 122 discussed above, and a CN device 1030 which may be implemented as the LMF 132 discussed above.

Referring to Fig. 11A, the terminal device 1010 may comprise one or more processors 1011, one or more memories 1012 and one or more transceivers 1013 interconnected through one or more buses 1014. The one or more buses 1014 may be address, data, or control buses, and may include any interconnection mechanism such as series of lines on a motherboard or integrated circuit, fiber, optics or other optical communication equipment, and the like. Each of the one or more transceivers 1013 may comprise a receiver and a transmitter, which are connected to one or more antennas 1016. The terminal device 1010 may wirelessly communicate with the RAN device 1020 through the one or more antennas 1016. The one or more memories 1012 may include instructions 1015 which, when executed by the one or more processors 1011, may cause the terminal device 1010 to perform operations and procedures relating to the UE 110 as described above.

The RAN device 1020 may comprise one or more processors 1021, one or more memories 1022, one or more transceivers 1023 and one or more network interfaces 1027 interconnected through one or more buses 1024. The one or more buses 1024 may be address, data, or control buses, and may include any interconnection mechanism such as a series of lines on a motherboard or integrated circuit, fiber, optics or other optical communication equipment, and the like. Each of the one or more transceivers 1023 may comprise a receiver and a transmitter, which are connected to one or more antennas 1026. The RAN device 1020 may wirelessly communicate with terminal device 1010 through the one or more antennas 1026. The one or more network interfaces 1027 may provide wired or wireless communication links through which the RAN device 1020 may communicate with other network devices, entities, elements or functions. For example, the RAN device 1020 may communicate with the CN device 1030 via backhaul connections 1028. The one or more memories 1022 may include instructions 1025 which, when executed by the one or more processors 1021, may cause the RAN device 1020 to perform operations and procedures relating to the base stations 122 as described above.

The CN device 1030 may comprise one or more processors 1031, one or more memories 1032, and one or more network interfaces 1037 interconnected through one or more buses 1034. The one or more buses 1034 may be address, data, or control buses, and may include any interconnection mechanism such as a series of lines on a motherboard or integrated circuit, fiber, optics or other optical communication equipment, and the like. The CN device 1030 may operate as a core network function node and wired or wirelessly communicate with the RAN device 1020 through one or more links. The one or more network interfaces 1037 may provide wired or wireless communication links through which the CN device 1030 may communicate with other network devices, entities, elements or functions. The one or more memories 1032 may include instructions 1035 which, when executed by the one or more processors 1031, may cause the CN device 1030 to perform operations and procedures relating to the LMF 132 as described above.

Fig. 11B is a schematic block diagram illustrating a tracking source device 1040 according to an example embodiment of the present disclosure. The tracking source device 1040 may be implemented as the UE 110 discussed above, the XR application server 142 discussed above, or the tracking server 150 discussed above.

Referring to Fig. 11B, the tracking source device 1040 may comprise one or more processors 1041 and one or more memories 1042 interconnected through one or more buses 1044. The one or more buses 1044 may be address, data, or control buses, and may include any interconnection mechanism such as series of lines on a motherboard or integrated circuit, fiber, optics or other optical communication equipment, and the like. The one or more memories 1042 may include instructions 1045 which, when executed by the one or more processors 1041, may cause the tracking source device 1040 to perform operations and procedures relating to the UE 110, the application server 142 or the tracking server 150 as described above.

The one or

more processors

1011, 1021, 1031 and 1041 discussed above may be of any appropriate type that is suitable for the local technical network, and may include one or more of general purpose processors, special purpose processor, microprocessors, a digital signal processor (DSP) , one or more processors in a processor based multi-core processor architecture, as well as dedicated processors such as those developed based on Field Programmable Gate Array (FPGA) and Application Specific Integrated Circuit (ASIC) . The one or

more processors

1011, 1021, 1031 and 1041 may be configured to control other elements of the UE/network device/network element and operate in cooperation with them to implement the procedures discussed above.

The one or

more memories

1012, 1022, 1032 and 1042 may include at least one storage medium in various forms, such as a transitory memory and/or a non-transitory memory. The transitory memory may include, but not limited to, for example, a random access memory (RAM) or a cache. The non-transitory memory may include, but not limited to, for example, a read only memory (ROM) , a hard disk, a flash memory, and the like. The term “non-transitory, ” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM) . Further, the one or

more memories

1012, 1022, 1032 and 1042 may include but not limited to an electric, a magnetic, an optical, an electromagnetic, an infrared, or a semiconductor system, apparatus, or device or any combination of the above.

It would be understood that blocks in the drawings may be implemented in various manners, including software, hardware, firmware, or any combination thereof. In some embodiments, one or more blocks may be implemented using software and/or firmware, for example, machine-executable instructions stored in the storage medium. In addition to or instead of machine-executable instructions, parts or all of the blocks in the drawings may be implemented, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-Programmable Gate Arrays (FPGAs) , Application-Specific Integrated Circuits (ASICs) , Application-Specific Standard Products (ASSPs) , System-on-Chip systems (SOCs) , Complex Programmable Logic Devices (CPLDs) , etc.

Some exemplary embodiments further provide program code or instructions which, when executed by one or more processors, may cause a device or apparatus to perform the procedures described above. The program code or instructions for carrying out procedures of the exemplary embodiments may be written in any combination of one or more programming languages. The program code or instructions may be provided to one or more processors or controllers of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program code or instructions, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code or instructions may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

Some exemplary embodiments further provide a computer program product or a computer readable medium having the program code or instructions stored therein. The computer readable medium may be any tangible medium that may contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. The machine readable medium may be a machine readable signal medium or a machine readable storage medium. A machine readable medium may include but is not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the machine readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

As used herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” and similar wording, where the list of two or more elements are joined by “and” or “or” , mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the subject matter has been described in a language that is specific to structural features and/or method actions, it is to be understood the subject matter defined in the appended claims is not limited to the specific features or actions described above. On the contrary, the above-described specific features and actions are disclosed as an example of implementing the claims.

Claims

A terminal device comprising:

at least one processor; and

at least one memory storing instructions which, when executed by the at least one processor, cause the terminal device at least to:

register a tracking source device for a service with a network device, the tracking source device being selected from a server providing the service, the terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.
The terminal device of claim 1, wherein, in a case where the terminal device is registered as the tracking source device for the service with the network device, the at least one memory further stores instructions which, when executed by the at least one processor, cause the terminal device at least to:

receive a request for tracking information from the network device; and

send tracking information to the network device, the tracking information comprising pose information of the terminal device and an indication of the service received by the terminal device.
The terminal device of claim 2, wherein the tracking information is sent via an application layer message.
The terminal device of any one of claims 1-3, wherein the network device comprises a radio access network device or a core network device.
The terminal device of any one of claim 1-4, wherein the service is an extended reality service.
A network device comprising:

at least one processor; and

at least one memory storing instructions which, when executed by the at least one processor, cause the network device at least to:

receive, from a terminal device receiving a service, registration of a tracking source device for the service;

send, to the tracking source device, a request for tracking information of the terminal device; and

receive, from the tracking source device, the tracking information of the terminal device, the tracking information comprising pose information of the terminal device and an indication of the service received by the terminal device.
The network device of claim 6, wherein the network device is a core network device, the at least one memory further stores instructions which, when executed by the at least one processor, cause the core network device at least to:

determine pose information of the terminal device based on the received tracking information; and

inform a radio access network device serving the terminal device of the pose information of the terminal device.
The network device of claim 7, wherein the core network device receives the tracking information via an application layer message and informs the pose information of the terminal device to the radio access network device via a network inner signaling.
The network device of claim 6, wherein the network device is a radio access network device, the at least one memory further stores instructions which, when executed by the at least one processor, cause the radio access network device at least to:

determine pose information of the terminal device based on the received tracking information;

predict size of a next frame of the service based on at least the pose information of the terminal device; and

optimize radio resource configuration for transmission of the service based on the predicted size of the next frame of the service.
The network device of any one of claims 6-9, wherein, the pose information of the terminal device indicates at least one of the following:

pose of the terminal device; or

pose change of the terminal device.
The network device of any one of claims 6-10, wherein the tracking source device is selected from a server providing the service, the terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.
The network device of any one of claims 6-11, wherein the service is an extended reality service.
A tracking source device comprising:

at least one processor; and

at least one memory storing instructions which, when executed by the at least one processor, cause the tracking source device at least to:

receive, from a network device, a request for tracking information of a terminal device receiving a service; and

send, to the network device, the tracking information of the terminal device, the tracking information comprising pose information of the terminal device and an indication of the service received by the terminal device.
The tracking source device of claim 13, wherein the indication of the service received by the terminal device comprises an identity of a quality of service flow for the service, and the tracking source device receives the identity of the quality of service flow for the service in the request for tracking information.
The tracking source device of claim 13 or 14, wherein the tracking source device comprises a server providing the service, the terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.
The tracking source device of any one of claims 13-15, wherein the tracking information of the terminal device is sent to the network device via an application layer message.
The tracking source device of any one of claim 13-16, wherein the service is an extended reality service.
A method comprising:

registering a tracking source device for a service with a network device, the tracking source device being selected from a server providing the service, a terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.
The method of claim 18, wherein in a case where the terminal device is registered as the tracking source device for the service, the method further comprises:

receiving a request for tracking information from the network device; and

sending tracking information to the network device, the tracking information comprising pose information of the terminal device and an indication of the service received by the terminal device.
The method of claim 19, wherein the tracking information is sent via an application layer message.
The method of any one of claims 18-20, wherein the network device comprises a radio access network device or a core network device.
The method of any one of claim 18-21, wherein the service is an extended reality service.
A method comprising:

receiving, at a network device from a terminal device receiving a service, registration of a tracking source device for the service;

sending, to the tracking source device, a request for tracking information of the terminal device; and

receiving, from the tracking source device, the tracking information of the terminal device, the tracking information comprising pose information of the terminal device and an indication of the service received by the terminal device.
The method of claim 23, wherein the network device is a core network device, and the method further comprises:

determining pose information of the terminal device based on the received tracking information; and

informing a radio access network device serving the terminal device of the pose information of the terminal device.
The method of claim 24, wherein the core network device receives the tracking information via an application layer message and informs the pose information of the terminal device to the radio access network device via a network inner signaling.
The method of claim 23, wherein the network device is a radio access network device, and the method further comprises:

determining pose information of the terminal device based on the received tracking information;

predicting size of a next frame of the service based on at least the pose information of the terminal device; and

optimizing radio resource configuration for transmission of the service based on the predicted size of the next frame of the service.
The method of any one of claims 23-26, wherein, the pose information of the terminal device indicates at least one of the following:

pose of the terminal device; or

pose change of the terminal device.
The method of any one of claims 23-27, wherein the tracking source device is selected from a server providing the service, the terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.
The method of any one of claims 23-28, wherein the service is an extended reality service.
A method comprising:

receiving, at a tracking source device from a network device, a request for tracking information of a terminal device receiving a service; and

sending, to the network device, the tracking information of the terminal device, the tracking information comprising pose information of the terminal device and an indication of the service received by the terminal device.
The method of claim 30, wherein the indication of the service received by the terminal device comprises an identity of a quality of service flow for the service, and the tracking source device receives the identity of the quality of service flow for the service in the request for tracking information.
The method of claim 30 or 31, wherein the tracking source device comprises a server providing the service, the terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.
The method of any one of claims 30-32, wherein the tracking information of the terminal device is sent to the network device via an application layer message.
The method of any one of claims 30-33, wherein the service is an extended reality service.
An apparatus comprising:

means for registering a tracking source device for a service with a network device, the tracking source device being selected from a server providing the service, a terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.
An apparatus comprising:

means for receiving, at a network device from a terminal device receiving a service, registration of a tracking source device for the service;

means for sending, to the tracking source device, a request for tracking information of the terminal device; and

means for receiving, from the tracking source device, the tracking information of the terminal device, the tracking information comprising pose information of the terminal device and an indication of the service received by the terminal device.
An apparatus comprising:

means for receiving, at a tracking source device from a network device, a request for tracking information of a terminal device receiving a service; and

means for sending, to the network device, the tracking information of the terminal device, the tracking information comprising pose information of the terminal device and an indication of the service received by the terminal device.
A computer readable medium comprising instructions which, when executed by an apparatus, cause the apparatus at least to:

register a tracking source device for a service with a network device, the tracking source device being selected from a server providing the service, a terminal device receiving the service, or a tracking server configured to track pose of the terminal device receiving the service.
A computer readable medium comprising instructions which, when executed by an apparatus, cause the apparatus at least to:

receive, at a network device from a terminal device receiving a service, registration of a tracking source device for the service;

send, to the tracking source device, a request for tracking information of the terminal device; and

receive, from the tracking source device, the tracking information of the terminal device, the tracking information comprising pose information of the terminal device and an indication of the service received by the terminal device.
A computer readable medium comprising instructions which, when executed by an apparatus, cause the apparatus at least to:

receive, at a tracking source device from a network device, a request for tracking information of a terminal device receiving a service; and

send, to the network device, the tracking information of the terminal device, the tracking information comprising pose information of the terminal device and an indication of the service received by the terminal device.