WO2024000469A1

WO2024000469A1 - Schemes on gnss validity duration extension in iot ntn

Info

Publication number: WO2024000469A1
Application number: PCT/CN2022/102977
Authority: WO
Inventors: Wen Tang; Gilles Charbit
Original assignee: Mediatek Singapore Pte. Ltd.
Priority date: 2022-06-30
Filing date: 2022-06-30
Publication date: 2024-01-04
Also published as: WO2024001686A1

Abstract

Methods for obtaining GNSS validity duration extension and decrease frequency for GNSS fix with time and frequency correction enhancements, so that save UE power consumption and needs to design the scheme to make network and UE have same understanding of updated GNSS validity duration, to ensure the normal operation of IoT NTN system.

Description

SCHEMES ON GNSS VALIDITY DURATION EXTENSION IN IOT NTN

FIELD

This disclosure relates generally to wireless communications, and, more particularly, to methods and apparatus about time and frequency correction enhancements and GNSS validity duration extension in IoT NTN.

BACKGROUND

In scenarios with large transmission delay, such as the IoT NTN, in order to obtain GNSS validity duration extension and decrease frequency for GNSS fix, so that increase throughput and save UE power consumption, time and frequency correction enhancements are effective solutions.

SUMMARY

In NTN (Non-Terrestrial Network) system, due to large time delay and Doppler frequency shift, UE needs to do pre-compensation of time delay and frequency offset based on UE GNSS and ephemeris related parameters. For GNSS position fix, hot start requires about 1～2 seconds, warm start requires several seconds, and cold start requires about 30 seconds. The power consumption and throughput decrease for UE is enormous when UE needs to operate GNSS position fix in connected. Based on this, considering the IoT NTN scenario, the invention designs schemes to do time and frequency correction enhancements and GNSS validity duration extension, to ensure decreased frequency for GNSS fix, so that save UE power consumption.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. The UE receives the first information to do uplink time and frequency correction. The first information indicates time and /or frequency correction information. The UE determines GNSS status and reports GNSS status periodically or event trigged.

To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed, and this description is intended to include all such aspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a diagram illustrating an example of the first information indication between UE and network.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed 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 structures and components are shown in block diagram form in order to avoid obscuring such concepts.

Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described i the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements” ) . These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

In scenarios with large transmission delay, such as NTN system, UE GNSS is necessary for time and frequency synchronization. At present, the method proposed in 3GPP R17 to do GNSS position fix is that UE needs to have a valid GNSS fix before going to connected and when the GNSS fix becomes outdated in RRC_CONNECTED mode, the UE goes to IDLE mode. However, in R18, there is conclusion that IoT NTN UE may need to re-acquire a valid GNSS position fix in long connection time. Depending on UE mobility, UE in RRC-connected state will need a new GNSS position fix in order to accommodate the accumulated time and frequency errors to reduce the possible radio link failure. UEs especially with high speed may need frequent GNSS position fix during long-term connections, which will introduce large power consumption.

This invention is motivated by, but not limited to, an IoT NTN scenario. In such a scenario, it is beneficial to obtain GNSS validity duration extension and decrease frequency for GNSS position fix with time and frequency correction enhancements, so that save UE power consumption and needs to design the scheme to make network and UE have same understanding of updated GNSS validity duration, to ensure the normal operation of NTN system.

NTN refers to a network that uses radio frequency and information processing resources carried on high, medium and low orbit satellites or other high-altitude communication platforms to provide communication services for UEs. According to the load capacity on the satellite, there are two typical scenarios: transparent payload and regenerative payload. The transparent payload mode means that the satellite will not process the signal and waveform in the communication service, but only forward the data as an RF amplifier. Regenerative payload mode refers to the satellite, besides RF amplification, also has the processing capabilities of modulation/demodulation, coding/decoding, switching, routing and so on.

In order to ensure the normal operation of IoT NTN system, UE needs to do pre-compensation of time delay and frequency offset based on UE GNSS and ephemeris related parameters. In 3GPP R17 for short sporadic transmission, the GNSS acquire and GNSS validity duration reported has been discussed and relevant agreements have been obtained.

In 3GPP R18 for long-term connection, the GNSS related discussion has been made and relevant agreements have been obtained in RAN1 109e.

Depending on UE mobility, UE in RRC-connected state may need a new GNSS position fix in order to accommodate the accumulated time and frequency errors to reduce the possible radio link failure. UEs especially with high speed may need frequent GNSS position fix during long-term connections, which will introduce large power consumption. As the velocity of UE may differ in a wide range, the impact of GNSS operation to IoT devices’ battery lives will be also quite different. For worst cases, the battery life of an IoT device will reduce from more than ten years to less than one year.

The GNSS validity duration reported by UE is mainly evaluated by its speed and RAN4 requirement on TA error. However, close loop time correction, which is an agreed operation, can partially compensate the TA error caused by UE’s movement. The actual validity duration of GNSS position fix can be longer than the one reported by UE without considering close loop time correction. With more correction on time and frequency, less GNSS position fix is needed.

Hence, further scheme design needs to be carried out to obtain GNSS validity duration extension and decrease frequency for GNSS fix with time and frequency correction enhancements, so that save UE power consumption and needs to design the scheme to make network and UE have same understanding of updated GNSS validity duration, to ensure the normal operation of IoT NTN system.

More specifically, we propose to consider the following alternatives for IoT NTN:

Alternative#1: time and frequency correction enhancements

UE can receive closed loop time and frequency correction

●in the legacy UL Compensation Gap (UCG) of length 40 ms.

●in new scheduling gap where the gap is scheduled for UE to re-acquire GNSS position fix

●the closed loop frequency correction can be indicated with MAC CE or RRC signaling.

Note 1: The unit of the value (corresponding to closed loop frequency correction) is 100Hz or 50Hz. The range of the value (corresponding to closed loop frequency correction) is -1500Hz to +1500Hz.

Alternative#2: GNSS validity duration extension

UE can report GNSS status (periodic report/event trigger) .

□ When GNSS status is 00, trigger GNSS measurement (request the scheduling gap from network to do GNSS measurement) and the length for GNSS measurement is less than X seconds, where X is predefined value or reported GNSS position fix measurement length (which means the length for GNSS measurement is shorter than the one reported) .

□ When GNSS status is 01, trigger GNSS measurement (request the scheduling gap from network to do GNSS measurement) and the length for GNSS measurement is more than X seconds, where X is predefined value or reported GNSS position fix measurement length (which means the length for GNSS measurement is more than the one reported) .

□ When GNSS status is 10, new valid GNSS remaining validity duration can be prolonged Ys compared to current valid remaining GNSS validity duration, where Y is predefined value.

□ When GNSS status is 11, new valid GNSS remaining validity duration can be prolonged Zs compared to current valid remaining GNSS validity duration, where Z is predefined value.

Network can configure a scheduling gap for UE to do GNSS measurement when received GNSS status is 00 or 01.

Network can know the updated remaining GNSS validity duration when received GNSS status is 10 or 11.

Alternative#3: UE operation for GNSS measurement during C_DRX off duration

Based on the valid remaining GNSS validity duration, if it is longer than C_DRX periodicity duration, UE keeps same GNSS position fix without trigger a GNSS measurement to save power consumption; else, UE triggers new GNSS measurement.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” The word “exemplary” is used herein to mean “serving as an example, instance, or illustration. ” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C, ” “one or more of A, B, or C, ” “at least one of A, B, and C, ” “one or more of A, B, and C, ” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words “module, ” “mechanism, ” “element, ” “device, ” and the like may not be a substitute for the word “means. ” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for. ”

Claims

A method performed by a UE, comprising:

receiving the first information;

reporting GNSS status or reporting GNSS measurement request; and

triggering GNSS measurement.
The method of Claim 1, wherein the first information indicates closed loop time and frequency correction information, received in the legacy UL Compensation Gap (UCG) of length 40 ms, or received in the new scheduling gap where the gap is scheduled for UE to re-acquire GNSS position fix.
The method of Claim 2, the first information for closed loop frequency correction is indicated with MAC CE, or the first information for closed loop frequency correction is indicated with RRC signaling, where the unit of the first information for closed loop frequency correction is at least 100Hz or 50Hz, and the range of the first information for closed loop frequency correction is -1500Hz to +1500Hz.
The method of Claim 1, wherein GNSS status comprises at least one or more of the following:

GNSS measurement triggering information,

GNSS measurement length information, and

new valid remaining GNSS validity duration information.
The method of Claim 4, where GNSS status is M bits, corresponding to predefined information, where M is predefined value; when GNSS status is 2 bits, corresponding to predefined information with:

if GNSS status is 00, trigger GNSS measurement and the length for GNSS measurement is less than X seconds, where X is predefined value or X is reported GNSS position fix measurement length,

else if GNSS status is 01, trigger GNSS measurement and the length for GNSS measurement is more than X seconds, where X is predefined value or X is reported GNSS position fix measurement length,

else if GNSS status is 10, new valid GNSS remaining validity duration can be prolonged Y seconds compared to current valid remaining GNSS validity duration, where Y is predefined value,

else if GNSS status is 11, new valid GNSS remaining validity duration can be prolonged Z seconds compared to current valid remaining GNSS validity duration, where Z is predefined value.
The method of Claim 1, wherein reporting GNSS status periodically, or reporting GNSS status event trigged: based on the valid remaining GNSS validity duration, if it is longer than C_DRX periodicity duration, UE keeps same GNSS position without trigger a GNSS measurement to save power consumption; else if it is not longer than C_DRX periodicity duration, UE triggers new GNSS measurement.
The method of Claim 6, where UE triggers new GNSS measurement via reporting UE GNSS measurement request, where requesting the scheduling gap from network to make GNSS measurement.
A method performed by network, comprising:

transmitting the first information;

receiving GNSS status or GNSS measurement request; and

transmitting the scheduling gap for UE making GNSS measurement.
The method of Claim 1, wherein the first information indicates closed loop time and frequency correction information, transmits in the legacy UL Compensation Gap (UCG) of length 40 ms, or transmits in the new scheduling gap where the gap is scheduled for UE to re-acquire GNSS position fix.
The method of Claim 9, the first information for closed loop frequency correction is indicated with MAC CE, or the first information for closed loop frequency correction is indicated with RRC signaling, where the unit of the first information for closed loop frequency correction is at least 100Hz or 50Hz, and the range of the first information for closed loop frequency correction is -1500Hz to +1500Hz.
The method of Claim 8, wherein GNSS status comprising at least one or more of the following:

GNSS measurement triggering information,

GNSS measurement length information,

new valid remaining GNSS validity duration information.
The method of Claim 11, where GNSS status is M bits, corresponding to predefined information, where M is predefined value; when GNSS status is 2 bits, corresponding to predefined information with:

if GNSS status is 00, network configures a scheduling gap for UE to do GNSS measurement and the length for GNSS measurement is less than X seconds, where X is predefined value or X is reported GNSS position fix measurement length,

else if GNSS status is 01, network configures a scheduling gap for UE to do GNSS measurement and the length for GNSS measurement is more than X seconds, where X is predefined value or X is reported GNSS position fix measurement length,

else if GNSS status is 10, new valid GNSS remaining validity duration can be prolonged Y seconds compared to current valid remaining GNSS validity duration, where Y is predefined value,

else if GNSS status is 11, new valid GNSS remaining validity duration can be prolonged Z seconds compared to current valid remaining GNSS validity duration, where Z is predefined value.
The method of Claim 8, wherein receiving GNSS status periodically, or receiving GNSS status event trigged.
The method of Claim 8, where network configures a scheduling gap for UE to do GNSS measurement: when receives GNSS measurement request.