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EP-4360369-B1 - CONFIGURING TIMING OFFSETS IN INTEGRATED ACCESS BACKHAUL (IAB) NETWORKS WITH MULTIPLE AVAILABLE TIMING MODES

EP4360369B1EP 4360369 B1EP4360369 B1EP 4360369B1EP-4360369-B1

Inventors

  • DORTSCHY, BORIS
  • ÅSTRÖM, Magnus

Dates

Publication Date
20260506
Application Date
20220525

Claims (13)

  1. A method for a first integrated access backhaul, IAB, network node configured to operate as a child node of a second IAB network node in an IAB network, the method comprising: receiving (1110), from the second IAB network node, an indication, TΔ-mode, of a timing offset between the second IAB network node's downlink, DL, transmission timing and the second IAB network node's uplink, UL, reception timing, wherein the indication includes a first portion and a second portion, the first portion indication indicates a particular timing offset, TΔ, and at least one of the first and second portions indicates a particular timing mode, Tmode; determining (1120) the particular timing mode, Tmode, used for communication between the first and second network nodes based on the at least one of the first portion and the second portion of the indication TΔ-mode, wherein Tmode is one of a plurality of available timing modes comprising a Case-1, a Case-6 and a Case-7; and determining the particular timing offset, TΔ, that is applicable to Tmode based on the first portion of the indication TΔ-mode; wherein determining Tmode comprises: i) determining (1121) that Tmode is a first one of the available timing modes when a function of TΔ, f(TΔ), is less than a threshold, or determining (1122) that Tmode is a second one of the available timing modes when f(TΔ) is not less than the threshold, or ii) determining Tmode based on the second portion of the indication TΔ-mode; and adjusting (1130) the first IAB network node's DL transmission timing based on the particular timing offset TΔ and the particular timing mode Tmode, comprising: determining a timing advance value, TAmode, associated with the particular timing mode Tmode, for the first IAB network node's UL transmission timing relative to the first IAB network node's DL reception timing; and setting the first IAB network node's DL transmission timing in advance of the first IAB network node's DL reception timing based on the timing advance value TAmode.
  2. The method of claim 1, wherein the first and second portions are disjoint.
  3. The method of any of claims 1-2, wherein: the plurality of available timing modes include the first available timing mode and at least two other available timing modes; and determining (1120) Tmode comprises: determining (1123) that Tmode is the first available timing mode when a function of TΔ, f(TΔ), is less than a threshold; and when f(TΔ) is not less than the threshold, determining (1124) that Tmode is one of the at least two other available timing modes and selecting Tmode from the at least two other available timing modes based on the second portion of the indication.
  4. The method of claim 3, wherein one of the following applies: the first available timing mode is Case-1 and the at least two other available timing modes include Case-6 and Case-7; or the first available timing mode is Case-6 and the at least two other available timing modes include Case-1 and Case-7
  5. The method of any of claims 1-4, wherein f(TΔ) is equal to TΔ.
  6. A method for a second integrated access backhaul, IAB, network node configured to operate as a parent node of a first IAB network node in an IAB network, the method comprising: sending (1220), to the first IAB network node, an indication, TΔ-mode, of a timing offset between the second IAB network node's downlink, DL, transmission timing and the second IAB network node's uplink, UL, reception timing, wherein the indication includes a first portion and a second portion, the first portion indication indicates a particular timing offset, TΔ, and at least one of the first and second portions indicates a particular timing mode, Tmode; wherein the indication indicates the particular timing mode, Tmode, used for communication between the first and second IAB network nodes based on the at least one of the first portion and the second portion of the indication TΔ-mode, wherein Tmode is one of a plurality of available timing modes comprising a Case-1, a Case-6 and a Case-7; and the indication indicates a particular timing offset, TΔ, that is applicable to Tmode based on the first portion of the indication TΔ-mode; wherein the indication indicates: i) that Tmode is a first one of the available timing modes based on a function of TΔ, f(TΔ), being less than a threshold, or Tmode is a second one of the available timing modes based on f(TΔ) being not less than the threshold, or ii) Tmode based on the second portion.
  7. The method of claim 6, further comprising performing (1230) at least one DL transmission to the first IAB network node and receiving at least one UL transmission from the first IAB network node based on TΔ and Tmode.
  8. The method of claim 6 or 7, wherein the first and second portions are disjoint.
  9. The method of any of claims 6-8, wherein: the plurality of available timing modes include a first available timing mode and at least two other available timing modes; when a function of TΔ, f(TΔ), is less than a threshold, the first portion indicates that Tmode is the first available timing mode; and when f(TΔ) is not less than the threshold, the second portion indicates one of the at least two other available timing modes as Tmode.
  10. The method of claim 9, wherein one of the following applies: the first available timing mode is Case-1 and the at least two other available timing modes include Case-6 and Case-7; or the first available timing mode is Case-6 and the at least two other available timing modes include Case-1 and Case-7
  11. The method of any of claims 6-10, wherein f(TΔ) is equal to TΔ.
  12. A first an integrated access backhaul, IAB, network node (311-315, 510, 520, 610, 1500) configured to operate as a child node of a second IAB network node (312, 321, 322, 520, 530, 620, 1500) in an IAB network (399, 500), the first IAB network node being further configured to: receive, from the second IAB network node, an indication, TΔ-mode, of a timing offset between the second IAB network node's downlink, DL, transmission timing and the second IAB network node's uplink, UL, reception timing, wherein the indication includes a first portion and a second portion, the first portion indication indicates a particular timing offset, TΔ, and at least one of the first and second portions indicates a particular timing mode, Tmode; determine the particular timing mode, Tmode, used for communication between the first and second IAB network nodes based on the at least one of the first portion and the second portion of the indication TΔ-mode, wherein Tmode is one of a plurality of available timing modes comprising a Case-1, a Case-6 and a Case-7; and determine the particular timing offset, TΔ, that is applicable to Tmode based on the first portion of the indication TΔ-mode; wherein determining Tmode comprises: i) determining (1121) that Tmode is a first one of the available timing modes when a function of TΔ, f(TΔ), is less than a threshold, or determining (1122) that Tmode is a second one of the available timing modes when f(TΔ) is not less than the threshold, or ii) determining Tmode based on the second portion of the indication TΔ-mode; and adjust the first IAB network node's DL transmission timing based on the particular timing offset TΔ and the particular timing mode Tmode, comprising: determining a timing advance value, TAmode, associated with the particular timing mode Tmode, for the first IAB network node's UL transmission timing relative to the first IAB network node's DL reception timing; and setting the first IAB network node's DL transmission timing in advance of the first IAB network node's DL reception timing based on the timing advance value TAmode.
  13. A second integrated access backhaul, IAB, network node (312, 321, 322, 520, 530, 620, 1500) configured to operate as a parent node of a first IAB network node (311-315, 510, 520, 610, 1500) in an IAB network (399, 500), the second IAB network node being further configured to: send, to the first IAB network node, an indication, TΔ-mode, of a timing offset between the second IAB network node's downlink, DL, transmission timing and the second IAB network node's uplink, UL, reception timing, wherein the indication includes a first portion and a second portion, the first portion indication indicates a particular timing offset, TΔ, and at least one of the first and second portions indicates a particular timing mode, Tmode; wherein the indication indicates the particular timing mode, Tmode, used for communication between the first and second IAB network nodes based on the at least one of the first portion and the second portion of the indication TΔ-mode, wherein Tmode is one of a plurality of available timing modes comprising a Case-1, a Case-6 and a Case-7; and the indication indicates a particular timing offset, TΔ, that is applicable to Tmode based on the first portion of the indication TΔ-mode; wherein the indication indicates: i) that Tmode is a first one of the available timing modes based on a function of TΔ, f(TΔ), being less than a threshold, or Tmode is a second one of the available timing modes based on f(TΔ) being not less than the threshold, or ii) Tmode based on the second portion.

Description

TECHNICAL FIELD The present application relates generally to the field of wireless communication networks, and more specifically to integrated access backhaul (IAB) networks in which the available wireless communication resources are shared between user access to the network and backhaul of user traffic within the network (e.g., to/from a core network). BACKGROUND Densification via the deployment of many macro or micro base stations is one way to satisfy the increasing demand for bandwidth and/or capacity in mobile networks, which is mainly driven by the increasing use of video streaming services. Due to the availability of more spectrum in the millimeter wave (mmW) band, deploying small cells that operate in this band is an attractive deployment option for these purposes. However, the normal approach of connecting the small cells to the operator's backhaul network with optical fiber can be expensive and impractical. Employing wireless links for connecting the small cells to the operator's network is a cheaper and more practical alternative. One such approach is an integrated access backhaul (IAB) network where the operator can utilize part of the radio resources for the backhaul link. Document WO 2021/106160 A1 (NTT DOCOMO INC [JP]) 3 June 2021 (2021-06-03) addresses the DL/UL timing alignment in an IAB network between parent and child nodes. In the IAB architecture, each IAB node includes both base station and a mobile terminal (MT) functionality. The base station functionality is used for downlink (DL) and uplink (UL) commutations with downstream nodes, such as other IAB nodes and user equipment (UEs, e.g., wireless devices). For example, if the downstream node is another IAB node, the base station functionality of the IAB node communicates with the MT functionality of the downstream node. More generally, MT functionality is used for communication with upstream nodes in the IAB network, including parent nodes. In general, an IAB node can derive the DL transmission timing of its parent node from the timing advance (TA) configuration used in the IAB node, together with information about the timing offset between the parent node's DL transmission and UL reception. Such timing offset information can be signalled by the parent node to the (child) IAB node. SUMMARY However, there are many different timing configurations (also referred as "modes" or "cases") that can be employed by IAB nodes, each of which may use a different type of timing offset. This can cause an IAB node various problems, difficulties, and/or issues in relation to its timing for communication with its parent node and with UEs or child IAB nodes. Accordingly, embodiments of the present disclosure address these and other problems, difficulties, and/or issues in wireless networks (e.g., 5G networks) comprising IAB nodes, thereby facilitating the otherwise-advantageous deployment of IAB solutions. The independent claims concerning methods for timing configuration in IAB networks (claims 1 and 6) and corresponding network nodes (claims 12 and 13) describe the invention. Some embodiments of the present disclosure include methods (e.g., procedures) for a first network node configured to operate as a child node of a second network node in an IAB network. These exemplary methods can include receiving, from the second network node, an indication (TΔ-mode) of a timing offset between the second network node's downlink (DL) transmission timing and the second network node's uplink (UL) reception timing. For example, the indication can be received in a medium access control (MAC) control element (CE). These exemplary methods can also include determining the following based on the indication: a particular timing mode (Tmode) used for communication between the first and second network nodes, wherein Tmode is one of a plurality of available timing modes; anda particular timing offset (TΔ) that is applicable to Tmode. These exemplary methods can also include adjusting the first network node's DL transmission timing based on TΔ. In some embodiments, determining Tmode includes determining that Tmode is a first one of the available timing modes when a function of TΔ, f(TΔ), is less than a threshold. In some of these embodiments, determining Tmode also includes determining that Tmode is a second one of the available timing modes when f(TΔ) is not less than the threshold. In some of these embodiments, the first available timing mode is Case-1 and the second available timing mode is either Case-6 or Case-7. In other of these embodiments, the first available timing mode is Case-6 and the second available timing mode is either Case-1 or Case-7. In other embodiments, the indication includes first and second portions, the first portion indication indicates TΔ, and at least one of the first and second portions indicates Tmode. In some cases, the first and second portions can be disjoint. In some of these embodiments, the plurality of available timing modes include the f