WO2023206137A1

WO2023206137A1 - Schemes on new data indicator for disabled harq feedback in iot ntn

Info

Publication number: WO2023206137A1
Application number: PCT/CN2022/089550
Authority: WO
Inventors: Wen Tang
Original assignee: Mediatek Singapore Pte. Ltd.
Priority date: 2022-04-27
Filing date: 2022-04-27
Publication date: 2023-11-02

Abstract

In the IoT scenario with large round-trip delay, in order to ensure the peak rate of information transmission, the disabling HARQ feedback scheme needs to be added to the existing HARQ scheme of IoT. Considering UE may misunderstand the third transmission with NDI 0 as retransmission of the first transmission with NDI 0 when the second transmission is missed by UE. A new data indication scheme for IoT equipment in the NTN scenarios with HARQ feedback disabling is innovatively proposed to ensure the information transmission reliability.

Description

SCHEMES ON NEW DATA INDICATOR FOR DISABLED HARQ FEEDBACK IN IOT NTN

FIELD

This disclosure relates generally to wireless communications, and, more particularly, to methods and apparatus about new data indication for disabled HARQ feedback in IoT NTN.

BACKGROUND

In scenarios with large transmission delay, such as the NTN, in order to increase throughput and save UE power consumption, HARQ feedback disabling is an effective solution for IoT system.

SUMMARY

HARQ is mainly used for scheduling management, such as the initial transmission and retransmission of information. In scenarios with large transmission delay, such as NTN, disabling HARQ feedback can reduce UE power consumption and reduce transmission delay. In addition, disabling HARQ feedback for a DL transmission can improve uplink throughput in large RTT scenarios as more resource would be available in uplink. The new data indicator (NDI) indicates whether the current transmission is new or retransmission. For the same HARQ process with HARQ feedback disabled, if there are three transmission respectively with NDI 0, 1, 0, UE may misunderstand the third transmission with NDI 0 as retransmission of the first transmission with NDI 0 when the second transmission is missed by UE. Based on this, considering the IoT NTN scenario, in the case of disabling HARQ feedback, the invention designs a scheme to help UE decide whether the transmission is new or retransmitted, to increase reliability and benefit 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 DCI, determines the DCI scheduled process is new or retransmitted based on not only NDI field with HARQ feedback disabling.

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

FIG. 1 is a diagram illustrating an example of wrong NDI indication of transmitted information.

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 in 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 the scenario with relatively small transmission delay, such as TN system, using HARQ feedback has many advantages, such as increasing transmission reliability. In scenarios with large transmission delay, such as NTN system, disabling HARQ feedback can reduce UE power consumption and transmission delay. In addition, disabling HARQ feedback for a DL transmission can improve uplink throughput in large RTT scenarios as more resource would be available in uplink.

NDI indicates whether the current transmission is new or retransmission. For the same HARQ process with HARQ feedback disabled, if there are three transmission respectively with NDI 0, 1, 0, UE may misunderstand the third transmission with NDI 0 as retransmission of the first transmission with NDI 0 when the second transmission is missed by UE.

This invention is motivated by, but not limited to, an IoT NTN scenario, in the case of HARQ feedback is disabled for the process. In such a scenario, it is possible to misunderstand the transmission is new or retransmitted and needs to design the scheme of determining the process is new or retransmitted to increase reliability and benefit UE power consumption.

IoT system is mainly divided into NB-IoT and eMTC, based on different system bandwidth and coverage. The bandwidth used by NB-IoT is about 200kHz and supports the transmission of low traffic data at a rate below 100kbps. EMTC technology utilizes 1.4MHz bandwidth and the maximum data transmission rate is 1Mbps. Based on the current spec 36.211 and 36.213, in the NB-IoT scenario, the downlink supports 1 or 2 HARQ processes, In the eMTC scenario, the downlink can support up to 16 HARQ processes for eMTC CEModeA and up to 4 HARQ processes for eMTC CEModeB.

Considering the problem of large transmission delay in NTN system, for example, 3GPP proposes disabling HARQ feedback for NR NTN to improve the system throughput. For NR NTN, the scheme of disabling HARQ feedback is agreed as “disabling of HARQ feedback is per HARQ process via UE specific RRC signaling” . When IoT equipment needs to be used in the scenario with large delay, disabling HARQ feedback is required to reduce the transmission delay and increase the transmission information throughput. In RAN#95e, the revised WID on IoT NTN enhancements has been endorsed for Release 18 and according to the WID, disabling of HARQ feedback for IoT NTN has been agreed in RAN meetings.

At present, for a DCI scheduled transmission, IoT UE decodes the DCI and determines whether the transmission is new or retransmitted based on NDI field in DCI. For the same HARQ process number or without HARQ process (when downlink only supports 1 HARQ process) , if NDI doesn’ t change, then UE thinks this transmission as the retransmitted one, else, as the new one. For the same HARQ process with HARQ feedback disabled, if there are three transmission respectively with NDI 0, 1, 0, UE may misunderstand the third transmission with NDI 0 as retransmission of the first transmission with NDI 0 when the second transmission is missed by UE. Hence, the method utilized in legacy IoT isn't applicable in IoT NTN scenarios with HARQ feedback disabling. The invention innovatively proposes a new data indication scheme for IoT equipment in the NTN scenarios with HARQ feedback disabling.

More specifically, we propose to consider the following new data indication alternatives scheme for IoT equipment in the NTN scenarios with disabling HARQ feedback:

Alternative#1: For NB-IoT NTN

Utilize “New data indicator” field (1 bit) and “HARQ-ACK resource” field (4 bit) in DCI.

When the “New data indicator” field is “0” as the previous process with the same process ID or without process ID.

When the “New data indicator” field is “1” as the previous process with the same process ID or without process ID.

Alternative#2: For eMTC CEModeA NTN

Utilize “New data indicator” field (1 bit) and “TPC command for PUCCH” field (2 bit) in DCI.

Alternative#3: For eMTC NTN

Utilize “New data indicator” field (1 bit) and “HARQ-ACK resource offset” field (2 bit) in DCI.

Alternative#4: For NB-IoT and eMTC NTN

Whatever the “New data indicator” field is, UE always takes the transmission as initial transmission.

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 HARQ feedback disabling indication information;

determining the state of the received information based on the NDI state indication information;

where the HARQ feedback disabling indication information indicates HARQ feedback disabling for the process.
The method of Claim 1, where the NDI state indication information, comprising:

“New data indicator” field (1 bit) and “HARQ-ACK resource” field (4 bit) in DCI;

or “New data indicator” field (1 bit) and “HARQ-ACK resource offset” field (2 bit) in DCI;

or “New data indicator” field (1 bit) and “TPC command for PUCCH” field (2 bit) in DCI.
The method of Claim 2, where the NDI state indication information comprising “New data indicator” field (1 bit) and “HARQ-ACK resource” field (4 bit) :

receiving “New data indicator” field and “HARQ-ACK resource” field in DCI,

determining the state of the received information as new information for “New data indicator” field is ‘0’ and “HARQ-ACK resource” field is ‘0000’ ;

or determining the state of the received information as new information for “New data indicator” field is ‘1’ and no matter what “HARQ-ACK resource” field is;

or determining the state of the received information as retransmitted information for “New data indicator” field is ‘0’ and “HARQ-ACK resource” field is not ‘0000’ ;

or receiving “New data indicator” field and “HARQ-ACK resource” field in DCI,

determining the state of the received information as new information for “New data indicator” field is ‘1’ and “HARQ-ACK resource” field is ‘0000’ ;

or determining the state of the received information as new information for “New data indicator” field is ‘0’ and no matter what “HARQ-ACK resource” field is;

or determining the state of the received information as retransmitted information for “New data indicator” field is ‘1’ and “HARQ-ACK resource” field is not ‘0000’ .
The method of Claim 2, where the NDI state indication information comprising “New data indicator” field (1 bit) and “HARQ-ACK resource offset” field (2 bit) :

receiving “New data indicator” field and “HARQ-ACK resource offset” field in DCI,

determining the state of the received information as new information for “New data indicator” field is ‘0’ and “HARQ-ACK resource offset” field is ‘00’ ;

or determining the state of the received information as new information for “New data indicator” field is ‘1’ and no matter what “HARQ-ACK resource offset” field is;

or determining the state of the received information as retransmitted information for “New data indicator” field is ‘0’ and “HARQ-ACK resource offset” field is not ‘00’ ;

or receiving “New data indicator” field and “HARQ-ACK resource offset” field in DCI,

determining the state of the received information as new information for “New data indicator” field is ‘1’ and “HARQ-ACK resource offset” field is ‘00’ ;

or determining the state of the received information as new information for “New data indicator” field is ‘0’ and no matter what “HARQ-ACK resource offset” field is;

or determining the state of the received information as retransmitted information for “New data indicator” field is ‘1’ and “HARQ-ACK resource offset” field is not ‘00’ .
The method of Claim 2, where the NDI state indication information comprising “New data indicator” field (1 bit) and “TPC command for PUCCH” field (2 bit) :

receiving “New data indicator” field and “HARQ-ACK resource offset” field in DCI,

determining the state of the received information as new information for “New data indicator” field is ‘0’ and “TPC command for PUCCH” field is ‘00’ ;

or determining the state of the received information as new information for “New data indicator” field is ‘1’ and no matter what “TPC command for PUCCH” field is;

or determining the state of the received information as retransmitted information for “New data indicator” field is ‘0’ and “TPC command for PUCCH” field is not ‘00’ ;

or receiving “New data indicator” field and “TPC command for PUCCH” field in DCI,

determining the state of the received information as new information for “New data indicator” field is ‘1’ and “TPC command for PUCCH field is ‘00’ ;

or determining the state of the received information as new information for “New data indicator” field is ‘0’ and no matter what “TPC command for PUCCH” field is;

or determining the state of the received information as retransmitted information for “New data indicator” field is ‘1’ and “TPC command for PUCCH” field is not ‘00’ .
The method of Claim 1, where the NDI state indication information, comprising:

“New data indicator” field (1 bit) ;

receiving “New data indicator” field,

determining the state of the received information as new information whatever “New data indicator” field is.