WO2025030479A1

WO2025030479A1 - Additional scheduling restriction for disabling harq feedback and harq a and b in iot ntn

Info

Publication number: WO2025030479A1
Application number: PCT/CN2023/112231
Authority: WO
Inventors: Yaohua CAI; Wen Tang
Original assignee: MediaTek Singapore Pte Ltd
Current assignee: MediaTek Singapore Pte Ltd
Priority date: 2023-08-10
Filing date: 2023-08-10
Publication date: 2025-02-13
Anticipated expiration: 2026-02-10

Abstract

Because of the large round-trip delay in the 3GPP IoT NTN scenario, HARQ feedback significantly decreases the data throughput. To improve the data throughput, and to save power consumption, in DL, disabling HARQ feedback was introduced; in UL, HARQ mode A and Mode B was introduced. When the HARQ mode A/B and disabling HARQ feedback are adopted, the scheduling restrictions need to be enhanced accordingly. The invention includes the enhancement of when UE starts and stops monitor PDCCH after the UL/DL transmission; enhancement of the DL/UL HARQ RTT timer or DRX-Inactivity timer if the DRX mode is configured in connected mode. The present invention considers the power consumption while maximizing the data through put.

Description

ADDITIONAL SCHEDULING RESTRICTION FOR DISABLING HARQ FEEDBACK AND HARQ A AND B IN IOT NTN

FIELD

This disclosure relates generally to wireless communications and, more particularly, to methods and apparatus for scheduling restriction for disabling HARQ feedback and HARQ A and B in IoT NTN.

BACKGROUND

NB-IoT/eMTC was specified in 3GPP Rel-13 in the purpose of providing a new access system with low complexity and low throughput to address the requirements of cellular internet of things (IoT) . In 3GPP Rel-17, to enable IoT operation in remote areas with low/no cellular connectivity for many different industries, NB-IoT/eMTC support for Non-Terrestrial Networks (NTN) were studied and specified.

Because of the large round-trip delay in the NTN scenario, HARQ feedback significantly decreases the data throughput. To improve the data throughput, and to save power consumption, in DL, disabling HARQ feedback was introduced; in UL, HARQ mode A and HARQ Mode B was introduced. The scheduling restrictions of PDCCH monitoring and the DL/UL HARQ RTT timer or DRX-inactivity timer are no longer valid when the HARQ mode A/B or disabling HARQ feedback are adopted. It is necessary to enhance the scheduling restrictions accordingly.

SUMMARY

The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

Various aspects of the present disclosure relate to scheduling restriction for disabling HARQ feedback and HARQ mode A/B in IoT NTN.

In an aspect of the disclosure, when a HARQ process configured as HARQ feedback disabled by per-HARQ process bitmap signaling and further reversed to HARQ feedback enabled by DCI, for NB-IoT the scheduling restriction is enhanced according and the HARQ RTT timer is refined in this case.

In an aspect of the disclosure, when the multiple TBs are scheduled for the interleaved case when HARQ-ACK bundling is configured; and when 2 HARQ processes configured as HARQ feedback disabled by per-HARQ process bitmap signaling and further reversed to HARQ feedback enabled by DCI, for NB-IoT the scheduling restriction is enhanced according and the HARQ RTT timer is refined in this case.

In an aspect of the disclosure, when the multiple TBs are scheduled for the non-interleaved case or for the interleaved case when HARQ-ACK bundling is not configured; and when 2 HARQ processes configured as HARQ feedback disabled by per-HARQ process bitmap signaling and further reversed to HARQ feedback enabled by DCI, for NB-IoT the scheduling restriction is enhanced according and the HARQ RTT timer is refined in this case.

In an aspect of the disclosure, when the HARQ process identifier 0 is configured as UL HARQ mode B, Msg3 of random access procedure in RRC_CONNECTED mode applies UL HARQ mode. The start time point of mac-ContentionResolutionTimer is enhanced accordingly.

In an aspect of the disclosure, when the HARQ process identifier 0 is configured as UL HARQ mode B, Msg3 of random access procedure in RRC_CONNECTED mode does not apply UL HARQ mode.

In an aspect of the disclosure, for NB-IoT UE, when the multi-TB is configured, solutions of UL HARQ mode configuration for multi-TB are proposed.

In an aspect of the disclosure, for NB-IoT UE, when the multi-TB is configured, solutions of DL HARQ feedback disabling configuration for multi-TB are proposed.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure. 1 is a diagram illustrating the relationship of no PDCCH monitoring restriction, UL HARQ RTT timer and DRX-Inactivity timer.

Figure. 2 is a diagram illustrating the relationship of DL HARQ RTT timer and DRX-Inactivity timer.

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.

The described invention operates in the context of 3GPP IoT NTN. The IoT system was specified in 3GPP Rel-13 in the purpose of provide new access system towards low complexity and low throughput to address the requirement of cellular internet of things (IoT) . IoT system is mainly divided into NB-IoT and eMTC, based on different system bandwidth and coverage. In 3GPP Rel-17, to enable IoT operation in remote areas with low/no cellular connectivity for many different industries, NB-IoT/eMTC support for Non-Terrestrial Networks (NTN) was studied and specified.

Because of the large round-trip delay in the NTN scenario, HARQ feedback significantly decreases the data throughput. To improve the data throughput, and to save power consumption, in DL, disabling HARQ feedback was introduced; in UL, HARQ mode A and Mode B was introduced. When the DL HARQ feedback is disabled, network can directly schedule the next transmission without waiting for the HARQ feedback. For UL transmission configured with HARQ mode A, likes the legacy, network will schedule the UE again after receiving the previous UL transmission. Network can indicate UE to retransmit the last UL packet or transmit a new UL packet depends on the decode result. However, for UL transmission configured with HARQ mode B, network does not need to schedule the UE after receiving the previous UL transmission, so that the long interval between the DCI N0 and NPUSCH format 1 can be to scheduling the next UL transmission of the same HARQ process. When the HARQ mode A/B and disabling HARQ feedback are adopted, the scheduling restrictions like when to start and stop monitor PDCCH after the UL/DL transmission and when to start DL/UL HARQ RTT timer or DRX-inactivity timer need to be enhanced accordingly. More specifically, we propose to consider the following alternatives:

Alternative #1: when a HARQ process configured as HARQ feedback disabled by per-HARQ process bitmap signaling and further reversed to HARQ feedback enabled by DCI, the NB-IoT UE does not wait for an RTT+3ms before monitoring NPDCCH for the same HARQ process. In this case, the HARQ RTT timer is set to k+1+N +deltaPDCCH, where k is the interval between the last subframe of the downlink transmission and the first subframe of the associated HARQ feedback transmission and N is the transmission duration in subframes of the associated HARQ feedback, and deltaPDCCH is the interval starting from the subframe following the last subframe of the associated HARQ feedback transmission plus 1 subframes to the first subframe of the next PDCCH occasion.

Alternative #2: when the multiple TBs are scheduled for the interleaved case when HARQ-ACK bundling is configured; and when 2 HARQ processes configured as HARQ feedback disabled by per-HARQ process bitmap signaling and further reversed to HARQ feedback enabled by DCI, the NB-IoT UE does not wait for an RTT+3ms before monitoring NPDCCH. The HARQ RTT timer is set to k+1+N +deltaPDCCH, where k is the interval between the last subframe of the downlink transmission and the first subframe of the associated HARQ feedback transmission and N is the transmission duration in subframes of the associated HARQ feedback, and deltaPDCCH is the interval starting from the subframe following the last subframe of the associated HARQ feedback transmission plus 1 subframes to the first subframe of the next PDCCH occasion.

Alternative #3: when the multiple TBs are scheduled for the non-interleaved case or for the interleaved case when HARQ-ACK bundling is not configured; and when 2 HARQ processes configured as HARQ feedback disabled by per-HARQ process bitmap signaling and further reversed to HARQ feedback enabled by DCI, the NB-IoT UE does not wait for an RTT+3ms before monitoring NPDCCH. The HARQ RTT timer is set to k+1+2*N +deltaPDCCH, where k is the interval between the last subframe of the downlink transmission and the first subframe of the associated HARQ feedback transmission and N is the transmission duration in subframes of the associated HARQ feedback, and deltaPDCCH is the interval starting from the subframe following the last subframe of the associated HARQ feedback transmission plus 1 subframes to the first subframe of the next PDCCH occasion.

Alternative #4: when the HARQ process identifier 0 is configured as UL HARQ mode B, Msg3 of random access procedure in RRC_CONNECTED mode applies UL HARQ mode. The HARQ mode configuration can be via RRC dedicated signaling or RRC broadcasted signaling. Or a sperate RRC configuration controls whether Msg3 of random access procedure in RRC_CONNECTED mode applies UL HARQ mode. UE starts mac-ContentionResolutionTimer and restarts mac-ContentionResolutionTimer at each HARQ retransmission of the bundle in the subframe containing the last repetition of the corresponding PUSCH transmission. UE is not required to monitor NPDCCH in 1 subframe after the last subframe of NPUSCH of Msg3.

Alternative #5: when the HARQ process identifier 0 is configured as UL HARQ mode B, Msg3 of random access procedure in RRC_CONNECTED mode does not apply UL HARQ mode.

Alternative #6: for NB-IoT UE, when the multi-TB is configured, RRC configuration of UL HARQ mode for HARQ process 0 applies for both HARQ processes.

Alternative #7: for NB-IoT UE, when the multi-TB is configured, UL HARQ mode for HARQ process 0 and HARQ process 1 must be configured with same value.

Alternative #8: when the multi-TB is configured, there is an additional RRC configuration besides the HARQ mode configuration that controls the HARQ mode of HARQ processes for multi-TB.

Alternative #9: for NB-IoT UE, when the multi-TB is configured, RRC configuration of DL HARQ feedback disabling for HARQ process 0 applies for both HARQ processes.

Alternative #10: for NB-IoT UE, when the multi-TB is configured, DL HARQ feedback disabling for HARQ process 0 and HARQ process 1 must be configured with same value.

Alternative #11: when the multi-TB is configured, there is an additional RRC configuration besides the HARQ feedback disabling configuration that controls the HARQ feedback disabling for multi-TB.

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, ” “UE, ” 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. ”

While aspects of the present disclosure have been described in conjunction with the specific embodiments thereof that are proposed as examples, alternatives, modifications, and variations to the examples may be made. Accordingly, embodiments as set forth herein are intended to be illustrative and not limiting. There are changes that may be made without departing from the scope of the claims set forth below.

Claims

A method of wireless communication comprising: scheduling restriction and HARQ RTT timer when HARQ processes configured as HARQ feedback disabled by per-HARQ process bitmap signaling and further reversed to HARQ feedback enabled by DCI.
The method of Claim 1, wherein scheduling restriction and HARQ RTT timer includes: when a HARQ process configured as HARQ feedback disabled by per-HARQ process bitmap signaling and further reversed to HARQ feedback enabled by DCI, the NB-IoT UE does not wait for an RTT+3ms before monitoring NPDCCH for the same HARQ process, in this case, the HARQ RTT timer is set to k+1+N +deltaPDCCH, where k is the interval between the last subframe of the downlink transmission and the first subframe of the associated HARQ feedback transmission and N is the transmission duration in subframes of the associated HARQ feedback, and deltaPDCCH is the interval starting from the subframe following the last subframe of the associated HARQ feedback transmission plus 1 subframes to the first subframe of the next PDCCH occasion.
The method of Claim 1, wherein scheduling restriction and HARQ RTT timer includes: when the multiple TBs are scheduled for the interleaved case when HARQ-ACK bundling is configured; and when 2 HARQ processes configured as HARQ feedback disabled by per-HARQ process bitmap signaling and further reversed to HARQ feedback enabled by DCI, the NB-IoT UE does not wait for an RTT+3ms before monitoring NPDCCH, the HARQ RTT timer is set to k+1+N +deltaPDCCH, where k is the interval between the last subframe of the downlink transmission and the first subframe of the associated HARQ feedback transmission and N is the transmission duration in subframes of the associated HARQ feedback, and deltaPDCCH is the interval starting from the subframe following the last subframe of the associated HARQ feedback transmission plus 1 subframes to the first subframe of the next PDCCH occasion.
The method of Claim 1, wherein scheduling restriction and HARQ RTT timer includes: when the multiple TBs are scheduled for the non-interleaved case or for the interleaved case when HARQ-ACK bundling is not configured; and when 2 HARQ processes configured as HARQ feedback disabled by per-HARQ process bitmap signaling and further reversed to HARQ feedback enabled by DCI, the NB-IoT UE does not wait for an RTT+3ms before monitoring NPDCCH, the HARQ RTT timer is set to k+1+2*N +deltaPDCCH, where k is the interval between the last subframe of the downlink transmission and the first subframe of the associated HARQ feedback transmission and N is the transmission duration in subframes of the associated HARQ feedback, and deltaPDCCH is the interval starting from the subframe following the last subframe of the associated HARQ feedback transmission plus 1 subframes to the first subframe of the next PDCCH occasion.
The method of Claim 1, wherein when the HARQ process identifier 0 is configured as UL HARQ mode B, Msg3 of random access procedure in RRC_CONNECTED mode applies UL HARQ mode, the HARQ mode configuration can be via RRC dedicated signaling or RRC broadcasted signaling, or a sperate RRC configuration controls whether Msg3 of random access procedure in RRC_CONNECTED mode applies UL HARQ mode, UE starts mac-ContentionResolutionTimer and restarts mac-ContentionResolutionTimer at each HARQ retransmission of the bundle in the subframe containing the last repetition of the corresponding PUSCH transmission, UE is not required to monitor NPDCCH in 1 subframe after the last subframe of NPUSCH of Msg3.
The method of Claim 1, wherein when the HARQ process identifier 0 is configured as UL HARQ mode B, Msg3 of random access procedure in RRC_CONNECTED mode does not apply UL HARQ mode.
The method of Claim 1, wherein when the multi-TB is configured, new methods of UL HARQ mode configuration and DL HARQ feedback disabling configuration for multi-TB.
The method of Claim 7, wherein UL HARQ mode configuration includes: RRC configuration of UL HARQ mode for HARQ process 0 applies for both HARQ processes.
The method of Claim 7, wherein UL HARQ mode configuration includes: UL HARQ mode for HARQ process 0 and HARQ process 1 must be configured with same value.
The method of Claim 7, wherein UL HARQ mode configuration includes: there is an additional RRC configuration besides the HARQ mode configuration that controls the HARQ mode of HARQ processes for multi-TB.
The method of Claim 7, wherein DL HARQ feedback disabling configuration includes: RRC configuration of DL HARQ feedback disabling for HARQ process 0 applies for both HARQ processes.
The method of Claim 7, wherein DL HARQ feedback disabling configuration includes: DL HARQ feedback disabling for HARQ process 0 and HARQ process 1 must be configured with same value.
The method of Claim 7, wherein DL HARQ feedback disabling configuration includes: there is an additional RRC configuration besides the HARQ feedback disabling configuration that controls the HARQ feedback disabling for multi-TB.