WO2020134215A1

WO2020134215A1 - Method for network node to switch format of medium access control subheader, and network node apparatus

Info

Publication number: WO2020134215A1
Application number: PCT/CN2019/106697
Authority: WO
Inventors: Jinhua Liu; Min Wang
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2018-12-29
Filing date: 2019-09-19
Publication date: 2020-07-02

Abstract

The present disclosure relates to a method for a network node to switch format of medium access control subheader, and a network node apparatus. The method may include: carrying (S101) a first format of MAC subheader when initiating a random access to an upstream node of the network node; receiving (S102), from the upstream node, a message indicating a switch to a second format of MAC subheader; and using (S103) the second format of MAC subheader, to communicate with the upstream node. There will be no ambiguity during switching the format of MAC subheader.

Description

METHOD FOR NETWORK NODE TO SWITCH FORMAT OF MEDIUM ACCESS CONTROL SUBHEADER, AND NETWORK NODE APPARATUS

TECHNICAL FIELD

The present disclosure relates generally to the technology of wireless communication, and in particular, to a method for a network node to switch format of medium access control subheader, and a network node apparatus.

BACKGROUND

In a communication network, different parameters for quality of service (QoS) management may be assigned to different apparatus. For example, a first apparatus and a second apparatus may have different configuration parameters corresponding to data transmission management in radio interface, such as Logic Channel Identifier/Logic Channel Group Identifier (LCID/LCGID) spaces.

These configuration parameters may be carried in Medium Control Access (MAC) subheader in a radio message, under the MAC protocol. Thus, one format of the Medium Control Access (MAC) subheader may be not enough for different apparatus.

However, more than one formats of MAC subheader for different apparatus would lead to an ambiguity that affects the performance of network communication between peer apparatus.

SUMMARY

Certain aspects of the present disclosure and their embodiments may provide solutions to these or other challenges. There are, proposed herein, various embodiments which address one or more of the issues disclosed herein.

A first aspect of the present disclosure provides a method for a network node to switch a format of Medium Access Control (MAC) subheader, including: carrying a first format of MAC subheader when initiating a random access to an upstream node of the network node; receiving, from the upstream node, a message indicating a switch to a second format of MAC subheader; and using the second format of MAC subheader, to communicate with the upstream node.

In embodiments of the present disclosure, using the second format of MAC subheader includes: using the second format of MAC subheader, following an Acknowledgement (ACK) message to a contention resolution message received from the upstream node.

In embodiments of the present disclosure, the message indicating the switch to the second format of MAC subheader is a Radio Resource Control (RRC) signaling message.

In embodiments of the present disclosure, the RRC signalling includes: a System Frame Number (SFN) , to indicate in which radio frame to start using the second format of MAC subheader.

In embodiments of the present disclosure, the message indicating the switch to the second format of MAC subheader includes a Medium Access Control Control Element (MAC CE) , so as to indicate the switch.

In embodiments of the present disclosure, using the second format of MAC subheader includes: using the second format of MAC subheader, following an ACK message to the message indicating the switch to the second format of MAC subheader.

In embodiments of the present disclosure, the message indicating the switch to the second format of MAC subheader includes a Physic Downlink Control Channel (PDCCH) order, so as to indicate the switch.

In embodiments of the present disclosure, using the second format of MAC subheader includes: using the second format of MAC subheader following an end of a transmission window of the PDCCH order.

In embodiments of the present disclosure, the PDCCH order includes a predefined Radio Network Temporary Identifier (RNTI) , so as to indicate the switch to the second format of MAC subheader; or a predefined format of the PDCCH order indicates the switch to the second format of MAC subheader.

In embodiments of the present disclosure, the PDCCH order is transmitted repeatedly within the transmission window, e.g. during a radio frame or half radio frame.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a first time point to switch. The first time point is before an initial transmission of a Transport Block (TB) in a data transmission period. The network node uses the second format of MAC subheader for the initial transmission, if the initial transmission of the TB is implemented after a first predetermined time period from the first time point. The first predetermined time period includes x time units, wherein x is a natural value and the time units can be but not limited by Orthogonal Frequency Division Multiplexing (OFDM) symbol, slot, radio frame, millisecond or micro second.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a second time point to switch. If the second time point is between an initial transmission of a TB and a Hybrid Automatic Repeat Request (HARQ) retransmission of the TB in a data transmission period, the network node uses the second format of MAC subheader for the HARQ retransmission.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a second time point to switch. If the second time point is between an initial transmission of a TB and a Hybrid Automatic Repeat Request (HARQ) retransmission of the TB in a data transmission period, the network node uses the first format of MAC subheader for the HARQ retransmission of the TB, and uses the second format of MAC subheader following an end of a transmission period of the TB.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a third time point to switch. If the third time point is in a data transmission period, the network node resets a HARQ entity.

In embodiments of the present disclosure, the HARQ entity returns a MAC Service Data Unit (SDU) of an unacknowledged MAC Protocol Data Unit (PDU) to a layer higher than a MAC layer, before being reset.

In embodiments of the present disclosure, the method further includes: receiving a broadcast about a specific Physical Random Access Channel (PRACH) resource pool preconfigured for the downstream node; and using the second format of MAC subheader during a random access procedure to the upstream node.

In embodiments of the present disclosure, a difference between the first format of MAC subheader and the second format of MAC subheader includes a change in a format of a field.

In embodiments of the present disclosure, the change relates to a field of Logical Channel Identifier (LCID) and/or Logical Channel Group Identifier (LCG ID) .

In embodiments of the present disclosure, the network node includes: a child Integrated Access Backhaul (IAB) node; and the upstream node includes: a parent IAB node, or a base station.

A second aspect of the present disclosure provides a method for a network node to switch a format of MAC subheader, including: receiving, from a downstream node of the network node, a request carrying a first format of MAC subheader to initiate a random access; and sending, to the downstream node, a message indicating a switch to a second format of MAC subheader.

In embodiments of the present disclosure, sending, to the downstream node, a message indicating a switch to a second format of MAC subheader including: sending, to the downstream node, a contention resolution message carrying the second format of MAC subheader.

In embodiments of the present disclosure, the message indicating the switch to the second format of MAC subheader is a Radio Resource Control (RRC) signalling.

In embodiments of the present disclosure, the method further includes: using the second format of MAC subheader, following an action of receiving, from the downstream node, an ACK message to the message indicating the switch to the second format of MAC subheader.

In embodiments of the present disclosure, the method further includes: using the second format of MAC subheader following an end of a transmission period of the PDCCH order.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a fourth time point to switch. The fourth time point is before an initial transmission of a Transport Block (TB) in a data transmission period. The network node uses the second format of MAC subheader for the initial transmission, if the initial transmission of the TB is implemented after a second predetermined time period from the fourth time point. The second predetermined time period includes y time units, wherein y is a natural value and the time units can be but not limited by Orthogonal Frequency Division Multiplexing (OFDM) symbol, slot, radio frame, millisecond or micro second.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a fifth time point to switch. If the fifth time point is between an initial transmission of a TB and a Hybrid Automatic Repeat Request (HARQ) retransmission of the TB in a data transmission period, the network node uses the second format of MAC subheader for the HARQ retransmission.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a fifth time point to switch. If the fifth time point is between an initial transmission of a TB and a Hybrid Automatic Repeat Request (HARQ) retransmission of the TB in a data transmission period, the network node uses the first format of MAC subheader for the HARQ retransmission of the TB, and uses the second format of MAC subheader following an end of a transmission period of the TB.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a sixth time point to switch. If the sixth time point is in a data transmission period, the network node resets a HARQ entity.

In embodiments of the present disclosure, the method further includes: broadcasting about a specific Physical Random Access Channel (PRACH) resource pool preconfigured for the downstream node; and receiving a request, carrying the second format of MAC subheader, to initiate a random access to the network node.

In embodiments of the present disclosure, the change relates to a field of Logical Channel Identifier (LC ID) and/or Logical Channel Group Identifier (LCG ID) .

In embodiments of the present disclosure, the downstream node includes: a child Integrated Access Backhaul (IAB) node. The network node includes: a parent IAB node, or a base station.

A third aspect of the present disclosure provides a network node, including: a processor; and a memory, containing instructions executable by the processor. The network node is operative to: carry a first format of MAC subheader when initiating a random access to an upstream node of the network node; receive, from the upstream node, a message indicating a switch to a second format of MAC subheader; and use the second format of MAC subheader to communicate with the upstream node.

In embodiments of the present disclosure, the network node is further operative to implement the any above mentioned method.

A fourth aspect of the present disclosure provides a network node, including: a processor; and a memory, containing instructions executable by the processor. The network node is operative to: receive, from a downstream node of the network node, a request carrying a first format of MAC subheader to initiate a random access; and send, to the downstream node, a message indicating a switch to a second format of MAC subheader.

A fifth aspect of the present disclosure provides computer readable storage medium having a computer program stored thereon, the computer program executable by an apparatus to cause the apparatus to carry out any above mentioned method.

BRIEF DESCRIPTION OF DRAWINGS

Through the more detailed description of some embodiments of the present disclosure in the accompanying drawings, the above and other objects, features and advantages of the present disclosure will become more apparent, wherein the same reference generally refers to the same components in the embodiments of the present disclosure.

Figure 1 is an exemplary block diagram showing network nodes to implement a method according to embodiments of the present disclosure;

Figure 2 is an exemplary flow chart showing a method for a network node to switch format of medium access control subheader according to embodiments of the present disclosure;

Figure 3 is an exemplary flow chart showing exemplary substeps of method as shown in figure 2;

Figure 4 is an exemplary time line showing switching of MAC subheader during data transmission;

Figure 5 is another exemplary time line showing switching of MAC subheader during data transmission;

Figure 6 is another exemplary flow chart showing a method for a network node to switch format of medium access control subheader according to embodiments of the present disclosure;

Figure 7 is a block diagram showing the network node in accordance with embodiments of the present disclosure;

Figure 8 is a block diagram showing a computer readable storage medium in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION

Some of the embodiments contemplated herein will now be described more fully with reference to the accompanying drawings. Other embodiments, however, are contained within the scope of the subject matter disclosed herein, the disclosed subject matter should not be construed as limited to only the embodiments set forth herein; rather, these embodiments are provided by way of example to convey the scope of the subject matter to those skilled in the art.

Generally, all terms used herein are to be interpreted according to their ordinary meaning in the relevant technical field, unless a different meaning is clearly given and/or is implied from the context in which it is used. All references to a/an/the element, apparatus, component, means, step, etc. are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any methods disclosed herein do not have to be performed in the exact order disclosed, unless a step is explicitly described as following or preceding another step and/or where it is implicit that a step must follow or precede another step. Any feature of any of the embodiments disclosed herein may be applied to any other embodiment, wherever appropriate. Likewise, any advantage of any of the embodiments may apply to any other embodiments, and vice versa. Other objectives, features and advantages of the enclosed embodiments will be apparent from the following description.

Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present disclosure should be or are in any single embodiment of the disclosure. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Furthermore, the described features, advantages, and characteristics of the disclosure may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the disclosure may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the disclosure.

As used herein, the term “network” , or “communication network/system” refers to a network/system following any suitable communication standards, such as new radio (NR) , long term evolution (LTE) , LTE-Advanced, wideband code division multiple access (WCDMA) , high-speed packet access (HSPA) , and so on. Furthermore, the communications between a terminal device and a network node in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , 4G, 4.5G, 5G communication protocols, and/or any other protocols either currently known or to be developed in the future.

The term “network node” or “network side node” refers to a network device with accessing function in a communication network via which a terminal device accesses to the network and receives services therefrom. The network node may include a base station (BS) , an access point (AP) , a multi-cell/multicast coordination entity (MCE) , a controller or any other suitable device in a wireless communication network. The BS may be, for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a next generation NodeB (gNodeB or gNB) , a remote radio unit (RRU) , a radio header (RH) , a remote radio head (RRH) , a relay, a low power node such as a femto, a pico, and so forth.

Yet further examples of the network node comprise multi-standard radio (MSR) radio equipment such as MSR BSs, network controllers such as radio network controllers (RNCs) or base station controllers (BSCs) , base transceiver stations (BTSs) , transmission points, transmission nodes, positioning nodes and/or the like. More generally, however, the network node may represent any suitable device (or group of devices) capable, configured, arranged, and/or operable to enable and/or provide a terminal device access to a wireless communication network or to provide some service to a terminal device that has accessed to the wireless communication network.

Further, term “network node” or “network side node” may also refer to a network device with core network function. The network node may refer to a mobility management entity (MME) , or a mobile switching center (MSC) .

The term “terminal device” refers to any end device that can access a communication network and receive services therefrom. By way of example and not limitation, the terminal device may refer to a user equipment (UE) , or other suitable devices. The UE may be, for example, a subscriber station, a portable subscriber station, a mobile station (MS) or an access terminal (AT) . The terminal device may include, but not limited to, portable computers, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, a mobile phone, a cellular phone, a smart phone, a tablet, a wearable device, a personal digital assistant (PDA) , a vehicle, and the like.

As yet another specific example, in an Internet of things (IoT) scenario, a terminal device may also be called an IoT device and represent a machine or other device that performs monitoring, sensing and/or measurements etc., and transmits the results of such monitoring, sensing and/or measurements etc. to another terminal device and/or a network equipment. The terminal device may in this case be a machine-to-machine (M2M) device, which may in a 3rd generation partnership project (3GPP) context be referred to as a machine-type communication (MTC) device.

As one particular example, the terminal device may be a UE implementing the 3GPP narrow band Internet of things (NB-IoT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances, e.g. refrigerators, televisions, personal wearables such as watches etc. In other scenarios, a terminal device may represent a vehicle or other equipment, for example, a medical instrument that is capable of monitoring, sensing and/or reporting etc. on its operational status or other functions associated with its operation.

As used herein, the terms “first” , “second” and so forth refer to different elements. The singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” as used herein, specify the presence of stated features, elements, and/or components and the like, but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. The term “based on” is to be read as “based at least in part on” . The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment” . The term “another embodiment” is to be read as “at least one other embodiment” . Other definitions, explicit and implicit, may be included below.

Figure 1 is an exemplary block diagram showing network nodes to implement a method according to embodiments of the present disclosure.

An Integrated Access Backhaul (IAB) structure is taken as an example. For a new radio (NR) system with IAB capability, an access point can setup a radio connection to another access point in order to reach a donor access point which has wireline backhaul, wherein an access point is also referred to as IAB node. The said radio connection between IAB nodes (IAB-N) is referred to as wireless backhaul or self-backhaul.

As shown in figure 1, the network node may be IAB node. An IAB node (IABN/IAB-N) 102 may be scheduled by its parent IAB-N 103 and this IAB-N 102 may also schedule the connected User Equipment (UE) 1020 or its child IAB-N 101. Scheduling based on Scheduling Request (SR) /Buffer Status Report (BSR) is supported. The parent IAB-N 103 may be a donor node which has wireline/cable backhaul 104.

The donor IAB-N (IAB-N x) 103 has a cable backhaul 104 to the gateway, IAB-N 102 acts as a bridge node between the IAB-N 103 and IAB-N 101, where IAB-N 102 is referred to as the parent IAB-N of IAB 101 and IAB-N 101 is referred to as the child IAB-N of IAB-N 102. Each IAB-N may also have terminal devices, such as UEs, connected to it. For example, the UE 1020 is connected to IAB-N 102, and the UEs 1010, 1011 are connected to IAB-N 101.

From a perspective of a network node under IAB structure, there can be three types of links: (1) upstream link to/from its parent IAB-N; (2) downstream link to/from its child IAB-N; and (3) a number of downlink/uplink access links to a couple of terminal devices served by the node. The first two types of links are also referred to as backhaul links.

The IAB node may be configured with different MAC subheader format than the existing MAC subheader in Release 15 of the 3rd generation partnership project (3GPP) technical specifications/standards (TS) , such as extended logical channel/logical channel group (LC/LCG) to transfer information from the downstream child IAB or the served UEs to the upstream parent IAB. These new MAC subheader uses an extension of configuration parameters, such as logical channel identifier/logical channel group identifier (LCID/LCGID) carried in a MAC subheader in a message. A normal UE may belong to a first apparatus and intends to use a first format (i.e. MAC subheader of Release 15) of MAC subheader. The IAB node may belong to a second apparatus and intends to use a second format of MAC subheader, which may be extended based on the first format of MAC subheader.

However, for initial access of an IAB node, the IAB node shall proceed the random access procedure in the same way as that a normal UE performs. In the random access channel (RACH) procedure, the IAB node would use the same MAC functionality while with the increased LCID/LCGID spaces which would affect the format of the MAC subheader. While at the same time, the gNB/IAB node may receive RA accesses initiated by normal UEs where the ordinary LCID/LCGID space is applied.

For example, in case contention based random access (CBRA) is applied, the IAB node 101 and UE 1020 may share a same Physical Random Access Channel (PRACH) preamble pool, so that its parent gNB/IAB node 102 would not be able to distinguish random accesses (RA) initiated by a UE 1020 from ones that are initiated by the IAB node 101. Therefore, the gNB may not be aware of which LCGID/LCHID space that the current RA procedure is taking, therefore, the gNB may not know which format of MAC subheader shall be applied in the RA messages. This would lead to an ambiguity that affects the performance of RA procedure.

Figure 2 is an exemplary flow chart showing a method for a network node to switch format of medium access control subheader according to embodiments of the present disclosure.

As shown in figure 2, for example, a network node 101 is a downstream node to initiate the RA procedure, and the network node 102 is an upstream node to accept the request of initiating the RA procedure.

The method implemented at the downstream node, network node 101, includes: step S101, carrying a first format of MAC subheader when initiating a random access to an upstream node of the network node; step S102, receiving, from the upstream node, a message indicating a switch to a second format of MAC subheader; and step S103, using the second format of MAC subheader, to communicate with the upstream node.

Accordingly, the method implemented at the upstream node, network node 102, includes: step S201, receiving, from a downstream node of the network node, a request carrying a first format of MAC subheader to initiate a random access; and step S202, sending, to the downstream node, a message indicating a switch to a second format of MAC subheader.

In embodiments of the present disclosure, the IAB node and the UE may carry the same first format of the MAC subheader to initiate the RA procedure. Then, after the upstream node, such as a gNB, identifies the IAB node from the UE, the upstream node may send a message indicating a switch to a second format of MAC subheader to the IAB node. Thus, the switch to the second format of MAC subheader is determined and notified by the upstream node. There will be no ambiguity, and the performance of RA procedure will be improved.

Figure 3 is an exemplary flow chart showing exemplary substeps of method as shown in figure 2.

As shown in figure 3, at the upstream node, namely network node 102, the step S202, sending, to the downstream node, a message indicating a switch to a second format of MAC subheader includes: substep S302, sending, to the downstream node, a contention resolution message carrying the second format of MAC subheader.

Accordingly, at the downstream node, namely network node 101, the step S103, using the second format of MAC subheader includes: substep S301, using the second format of MAC subheader, following an Acknowledgement (ACK) message to a contention resolution message received from the upstream node.

In embodiments of the present disclosure, the upstream node may switch to a second format of MAC subheader, by sending a contention resolution message carrying the second format of MAC subheader. As soon as the downstream node sends an ACK message to the contention resolution message, the downstream node switches to use the second format of the MAC subheader. No extra step or message is needed during switching the format of MAC subheader in a RA procedure. Further, as soon as the RA procedure finishes, the upstream node and the downstream node may communicate with each other using the second format of the MAC subheader. There will be no ambiguity either during RA or communication procedure, and the performance of RA procedure and communication procedure will be improved.

In embodiments of the present disclosure, the upstream node may identify the downstream node, based on a C-RNTI (Cell-Radio Network Temporary Identifier) , or any other unique identifier for a network node, such as Inactive Radio Network Identifier (I-RNTI) . Namely, the upstream node identifies whether a downstream node is an IAB node or just a normal UE, based on an identifier obtained from the downstream node during RA procedure. Then the upstream node will send contention solution message with the second format of MAC subheader to the IAB node, or send contention solution message with the first format of MAC subheader to the normal UE.

In embodiments of the present disclosure, the message indicating the switch of format may be not limited to the contention resolution message.

For example, in embodiments of the present disclosure, the message indicating the switch to the second format of MAC subheader is a Radio Resource Control (RRC) signaling message. Further, the RRC signalling includes: a System Frame Number (SFN) , to indicate in which radio frame to start using the second format of MAC subheader.

In embodiments of the present disclosure, as a specific indicator in the message, the message may include a Medium Access Control Control Element (MAC CE) , so as to indicate the switch. For such message with the specific MAC CE, the step S103 of the method implemented at the downstream node, namely network node 101, may include: using the second format of MAC subheader, following an ACK message to such message indicating the switch to the second format of MAC subheader.

In embodiments of the present disclosure, as another specific kind of message, the message indicating the switch to the second format of MAC subheader includes a Physic Downlink Control Channel (PDCCH) order, so as to indicate the switch.

In embodiments of the present disclosure, the step S103 of the method implemented at the downstream node, network node 101, may include: using the second format of MAC subheader following an end of a transmission window of the PDCCH order.

According to such embodiments, any kind of message, and any kind of specific indicator may be utilized to indicate the switch of the MAC subheader, and there will be no ambiguity.

Figure 4 is an exemplary time line showing switching of MAC subheader during data transmission.

As shown in figure 4, an uplink transmission is taken as an example, namely, the network node 101 transmits data to the network node 102. In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a first time point T1 to switch. The first time point T1 is before an initial transmission of a Transport Block (TB) in a data transmission period. The network node uses the second format of MAC subheader for the initial transmission, if the initial transmission of the TB is implemented after a first predetermined time period TP1 from the first time point T1. The first predetermined time period TP1 includes x time units, wherein x is a natural value and the time units can be but not limited by Orthogonal Frequency Division Multiplexing (OFDM) symbol, slot, radio frame, millisecond or micro second. The time unit may be slot, or millisecond. The first predetermined time period TP1 allows the network node to prepare the initial transmission of a Transport Block (TB) . Namely, if the network node can prepare the initial transmission of a Transport Block (TB) with in the first predetermined time period TP1, the second format will be utilized in this initial transmission, and following possible retransmissions.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a second time point T2 to switch. If the second time point is T2 between an initial transmission of a TB and a Hybrid Automatic Repeat Request (HARQ) retransmission of the TB in a data transmission period, as an option, the network node uses the second format of MAC subheader for the HARQ retransmission.

Namely, the MAC subheader for the HARQ retransmission will be different with previous transmissions of the TB with the first format MAC subheader, such as an initial transmission and/or a previous retransmission. Then in another node which receives the transmission, the received HARQ retransmission with the second format of MAC subheader is not combined with the previous transmission of the TB with the first format MAC subheader. A plurality of retransmissions with the second format of MAC subheader will be implemented to recover the TB, if necessary.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a second time point to switch. If the second time point is between an initial transmission of a TB and a Hybrid Automatic Repeat Request (HARQ) retransmission of the TB in a data transmission period, as another option, the network node uses the first format of MAC subheader for the HARQ retransmission of the TB, and uses the second format of MAC subheader following an end of a transmission period of the TB. Therefore, the number of the retransmissions needs not to be increased.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a third time point to switch. If the third time point is in a data transmission period, the network node resets a HARQ entity. The third time point may be any time point during the data transmission, including T1, T2, as shown in the figure 4.

Namely, upon the switch of the format of the MAC subheader, the HARQ entity is reset, and new format of the MAC subheader is applied after the HARQ entity resets. Further, in embodiments of the present disclosure, the HARQ entity returns a MAC Service Data Unit (SDU) of an unacknowledged MAC Protocol Data Unit (PDU) to a layer higher than a MAC layer, before being reset. The higher layer can deliver the SDUs for new transmissions after switching the format of MAC subheader.

According to such embodiments, even a switch is implemented during a data transmission, there will be no ambiguity, and the performance of the data transmission procedure is improved.

Figure 5 is another exemplary time line showing switching of MAC subheader during data transmission.

As shown in figure 5, the technical principle of the embodiments of the present disclosure is also applicable to the downlink transmission.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a fourth time point T4 to switch. The fourth time point T4 is before an initial transmission of a Transport Block (TB) in a data transmission period. The network node uses the second format of MAC subheader for the initial transmission, if the initial transmission of the TB is implemented after a second predetermined time period from the fourth time point T4. The second predetermined time period includes y time units, wherein y is a natural value and the time units can be but not limited by Orthogonal Frequency Division Multiplexing (OFDM) symbol, slot, radio frame, millisecond or micro second. The time unit may be slot, or millisecond. The second predetermined time period TP2 allows the network node to prepare the initial transmission of a Transport Block (TB) . Namely, if the network node can prepare the initial transmission of a Transport Block (TB) with in the second predetermined time period TP2, the second format will be utilized in this initial transmission, and following possible retransmissions. Since the upstream node, such as a base station, may have much powerful computing ability, the second predetermined time period TP2 may be shorter than the first predetermined time period TP1. Particularly, the parameter “y” may be equal to “0” , which means the upstream node will do not need extra preparation time period, since the preparation time for an initial transmission is short enough to be ignored.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a fifth time point T5 to switch. If the fifth time point T5 is between an initial transmission of a TB and a Hybrid Automatic Repeat Request (HARQ) retransmission of the TB in a data transmission period, as an option, the network node uses the second format of MAC subheader for the HARQ retransmission.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a fifth time point T5 to switch. If the fifth time point T5 is between an initial transmission of a TB and a Hybrid Automatic Repeat Request (HARQ) retransmission of the TB in a data transmission period, as another option, the network node uses the first format of MAC subheader for the HARQ retransmission of the TB, and uses the second format of MAC subheader following an end of a transmission period of the TB.

In embodiments of the present disclosure, the message indicating a switch to the second format of MAC subheader further indicates a sixth time point to switch. If the sixth time point is in a data transmission period, the network node resets a HARQ entity. The sixth time point may be any time point during the data transmission, including T4, T5, as shown in the figure 5.

Figure 6 is another exemplary flow chart showing a method for a network node to switch format of medium access control subheader according to embodiments of the present disclosure.

As shown in figure 6, the method implemented at the network node 101 may include: step S501, receiving a broadcast about a specific Physical Random Access Channel (PRACH) resource pool preconfigured for the downstream node; and step S502, using the second format of MAC subheader during a random access procedure to the upstream node. Specifically, the network node 101 may send a request carrying the second format of MAC subheader to initiate a random access.

Accordingly, the method implemented at the network node 102 may include: step S601, broadcasting about a specific Physical Random Access Channel (PRACH) resource pool preconfigured for the downstream node; and step S602, receiving a request, carrying the second format of MAC subheader, to initiate a random access to the network node.

Namely, when the specific Physical Random Access Channel (PRACH) resource pool is already configured for the IAB node, the upstream node will identify an IAB node at the initiation of the RA procedure. There will be no ambiguity, and the performance of RA procedure will be improved.

It should be understood that an apparatus may only selectively implement the methods shown in figure 2 or 6, or implement all of these methods in both figures 2 and 6, according to network configuration policy.

In embodiments of the present disclosure, a difference between the first format of MAC subheader and the second format of MAC subheader includes a change in a format of a field. In embodiments of the present disclosure, the change relates to a field of Logical Channel Identifier (LC ID) and/or Logical Channel Group Identifier (LCG ID) .

In embodiments of the present disclosure, the methods are illustrated separately with the

network nodes

101, 102, for clarity. However, it should be understood, any network node may implement both of the methods for downstream node and upstream node. For example, the network node 102 will function as upstream node when communicating with the network node 101, and will function as downstream node when commutating with the network node 103. The network node 102 will implement any of the steps as shown in figures 2 to 6.

Figure 7 is a block diagram showing the management node in accordance with embodiments of the present disclosure.

As shown in figure 7, a network node 101/102, including: a processor 701; and a memory 702, containing instructions executable by the processor 701. The network node 101 is operative to: carry (S101) a first format of MAC subheader when initiating a random access to an upstream node of the network node; receive (S102) , from the upstream node, a message indicating a switch to a second format of MAC subheader; and use (S103) the second format of MAC subheader to communicate with the upstream node.

The network node 102 is operative to: receive (S201) , from a downstream node of the network node, a request carrying a first format of MAC subheader to initiate a random access; and send (S202) , to the downstream node, a message indicating a switch to a second format of MAC subheader.

According to embodiments of the present disclosure, there will be no ambiguity either during RA or communication procedure when switching the format of the MAC subheader, and the performance of RA procedure and communication procedure will be improved.

The network node 101/102 is further operative to any other methods described above, such as further shown in figures 3-6.

For example, referring to figure 3 again, in embodiments of the present disclosure, the network node 101 is operative to, use (S301) the second format of MAC subheader, following an Acknowledgement (ACK) message to a contention resolution message received from the upstream node.

The network node 102 is operative to send (S302) , to the downstream node, a contention resolution message carrying the second format of MAC subheader.

For example, referring to figure 6 again, in embodiments of the present disclosure, the network node 101 is operative to, receive (S501) a broadcast about a specific Physical Random Access Channel (PRACH) resource pool preconfigured for the downstream node; and use (S502) the second format of MAC subheader during a random access procedure to the upstream node. Specifically, the network node 101 may send a request carrying the second format of MAC subheader to initiate a random access.

The network node 102 is operative to broadcast (S601) about a specific Physical Random Access Channel (PRACH) resource pool preconfigured for the downstream node; and receive (S602) a request, carrying the second format of MAC subheader, to initiate a random access to the network node.

The processor 701 may be any kind of processing component, such as one or more microprocessor or microcontrollers, as well as other digital hardware, which may include digital signal processors (DSPs) , special-purpose digital logic, and the like. The memory 702 may be any kind of storage component, such as read-only memory (ROM) , random-access memory, cache memory, flash memory devices, optical storage devices, etc.

The computer readable storage medium 800 has a computer program 801 stored thereon. The computer program 801 is executable by an apparatus to cause the apparatus to carry out the method described above, such as shown in figures 2-6.

The computer readable storage medium 800 may be configured to include memory such as RAM, ROM, programmable read-only memory (PROM) , erasable programmable read-only memory (EPROM) , electrically erasable programmable read-only memory (EEPROM) , magnetic disks, optical disks, floppy disks, hard disks, removable cartridges, or flash drives.

Due to embodiments in the present disclosure, there will be no ambiguity either during RA or communication procedure, and the performance of RA procedure and communication procedure will be improved.

It should be understood although an IAB structure is illustrated as an example, the method of embodiments of the present disclosure may be applicable to any situation which needs switching format of MAC subheader. For example, MAC subheader may be extended to cause different format of MAC subheader for access radio interface of NR network, and then the above method will be applicable.

In general, the various exemplary embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software that may be executed by a controller, microprocessor or other computing device, although the disclosure is not limited thereto. While various aspects of the exemplary embodiments of this disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

As such, it should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be practiced in various components such as integrated circuit chips and modules. It should thus be appreciated that the exemplary embodiments of this disclosure may be realized in an apparatus that is embodied as an integrated circuit, where the integrated circuit may include circuitry (as well as possibly firmware) for embodying at least one or more of a data processor, a digital signal processor, baseband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the exemplary embodiments of this disclosure.

It should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be embodied in computer-executable instructions, such as in one or more program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types when executed by a processor in a computer or other device. The computer executable instructions may be stored on a computer readable medium such as a hard disk, optical disk, removable storage media, solid state memory, RAM, etc. As will be appreciated by those skilled in the art, the functionality of the program modules may be combined or distributed as desired in various embodiments. In addition, the functionality may be embodied in whole or in part in firmware or hardware equivalents such as integrated circuits, field programmable gate arrays (FPGA) , and the like.

The present disclosure includes any novel feature or combination of features disclosed herein either explicitly or any generalization thereof. Various modifications and adaptations to the foregoing exemplary embodiments of this disclosure may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications will still fall within the scope of the non-limiting and exemplary embodiments of this disclosure.

Claims

A method for a network node to switch a format of Medium Access Control (MAC) subheader, comprising:

carrying (S101) a first format of MAC subheader when initiating a random access to an upstream node of the network node;

receiving (S102) , from the upstream node, a message indicating a switch to a second format of MAC subheader; and

using (S103) the second format of MAC subheader, to communicate with the upstream node.
The method according to claim 1, wherein using the second format of MAC subheader comprises:

using (S301) the second format of MAC subheader, following an Acknowledgement (ACK) message to a contention resolution message received from the upstream node.
The method according to claim 1, wherein the message indicating the switch to the second format of MAC subheader is a Radio Resource Control (RRC) signaling message.
The method according to claim 3, wherein the RRC signalling comprises: a System Frame Number (SFN) , to indicate in which radio frame to start using the second format of MAC subheader.
The method according to claim 1 or 2, wherein the message indicating the switch to the second format of MAC subheader comprises a Medium Access Control Control Element (MAC CE) , so as to indicate the switch.
The method according to claim 5, wherein using the second format of MAC subheader comprises:

using the second format of MAC subheader, following an ACK message to the message indicating the switch to the second format of MAC subheader.
The method according to claim 1 or 2, wherein the message indicating the switch to the second format of MAC subheader comprises a Physic Downlink Control Channel (PDCCH) order, so as to indicate the switch.
The method according to claim 7, wherein using the second format of MAC subheader comprises:

using the second format of MAC subheader following an end of a transmission window of the PDCCH order.
The method according to claim 7 or 8,

wherein the PDCCH order comprises a predefined Radio Network Temporary Identifier (RNTI) , so as to indicate the switch to the second format of MAC subheader; or

wherein a predefined format of the PDCCH order indicates the switch to the second format of MAC subheader.
The method according to any of claims 7 to 9, wherein the PDCCH order is transmitted repeatedly during a radio frame or half radio frame.
The method according to claim 1,

wherein the message indicating a switch to the second format of MAC subheader further indicates a first time point to switch;

wherein the first time point is before an initial transmission of a Transport Block (TB) in a data transmission period;

wherein the network node uses the second format of MAC subheader for the initial transmission, if the initial transmission of the TB is implemented after a first predetermined time period from the first time point; and

wherein the first predetermined time period comprises x time units, x is a natural value.
The method according to claim 1,

wherein the message indicating a switch to the second format of MAC subheader further indicates a second time point to switch; and

wherein if the second time point is between an initial transmission of a TB and a Hybrid Automatic Repeat Request (HARQ) retransmission of the TB in a data transmission period, the network node uses the second format of MAC subheader for the HARQ retransmission.
The method according to claim 1,

wherein the message indicating a switch to the second format of MAC subheader further indicates a second time point to switch; and

wherein if the second time point is between an initial transmission of a TB and a Hybrid Automatic Repeat Request (HARQ) retransmission of the TB in a data transmission period, the network node uses the first format of MAC subheader for the HARQ retransmission of the TB, and uses the second format of MAC subheader following an end of a transmission period of the TB.
The method according to claim 1,

wherein the message indicating a switch to the second format of MAC subheader further indicates a third time point to switch; and

wherein if the third time point is in a data transmission period, the network node resets a HARQ entity.
The method according to claim 14,

wherein the HARQ entity returns a MAC Service Data Unit (SDU) of an unacknowledged MAC Protocol Data Unit (PDU) to a layer higher than a MAC layer, before being reset.
The method according to any of claims 1 to 15, further comprising:

receiving (S501) a broadcast about a specific Physical Random Access Channel (PRACH) resource pool preconfigured for the downstream node;

using (S502) the second format of MAC subheader during a random access procedure to the upstream node.
The method according to any of claims 1 to 16, wherein a difference between the first format of MAC subheader and the second format of MAC subheader comprises a change in a format of a field.
The method according to any of claims 1 to 17, wherein the change relates to a field of Logical Channel Identifier (LC ID) and/or Logical Channel Group Identifier (LCG ID) .
The method according to any of claims 1 to 18,

wherein the network node comprises: a child Integrated Access Backhaul (IAB) node; and

wherein the upstream node comprises: a parent IAB node, or a base station.
A method for a network node to switch a format of MAC subheader, comprising:

receiving (S201) , from a downstream node of the network node, a request carrying a first format of MAC subheader to initiate a random access;

sending (S202) , to the downstream node, a message indicating a switch to a second format of MAC subheader.
The method according to claim 20,

wherein sending, to the downstream node, a message indicating a switch to a second format of MAC subheader comprising:

sending (S302) , to the downstream node, a contention resolution message carrying the second format of MAC subheader.
The method according to claim 20, wherein the message indicating the switch to the second format of MAC subheader is a Radio Resource Control (RRC) signalling.
The method according to claim 22, wherein the RRC signalling comprises: a System Frame Number (SFN) , to indicate in which radio frame to start using the second format of MAC subheader.
The method according to claim 20, wherein the message indicating the switch to the second format of MAC subheader comprises a Medium Access Control Control Element (MAC CE) , so as to indicate the switch.
The method according to claim 24, further comprising:

using the second format of MAC subheader, following an action of receiving, from the downstream node, an ACK message to the message indicating the switch to the second format of MAC subheader.
The method according to claim 20, wherein the message indicating the switch to the second format of MAC subheader comprises a Physic Downlink Control Channel (PDCCH) order, so as to indicate the switch.
The method according to claim 26, further comprising:

using the second format of MAC subheader following an end of a transmission period of the PDCCH order.
The method according to claim 26 or 27,

wherein the PDCCH order comprises a predefined Radio Network Temporary Identifier (RNTI) , so as to indicate the switch to the second format of MAC subheader; or

wherein a predefined format of the PDCCH order indicates the switch to the second format of MAC subheader.
The method according to any of claims 26 to 28, wherein the PDCCH order is transmitted repeatedly during a radio frame or half radio frame.
The method according to claim 20,

wherein the message indicating a switch to the second format of MAC subheader further indicates a fourth time point to switch;

wherein the fourth time point is before an initial transmission of a Transport Block (TB) in a data transmission period;

wherein the network node uses the second format of MAC subheader for the initial transmission, if the initial transmission of the TB is implemented after a second predetermined time period from the fourth time point; and

wherein the second predetermined time period comprises y time units, y is a natural value.
The method according to claim 20,

wherein the message indicating a switch to the second format of MAC subheader further indicates a fifth time point to switch;

wherein if the fifth time point is between an initial transmission of a TB and a Hybrid Automatic Repeat Request (HARQ) retransmission of the TB in a data transmission period, the network node uses the second format of MAC subheader for the HARQ retransmission.
The method according to claim 20,

wherein the message indicating a switch to the second format of MAC subheader further indicates a fifth time point to switch;

wherein if the fifth time point is between an initial transmission of a TB and a Hybrid Automatic Repeat Request (HARQ) retransmission of the TB in a data transmission period, the network node uses the first format of MAC subheader for the HARQ retransmission of the TB, and uses the second format of MAC subheader following an end of a transmission period of the TB.
The method according to claim 20,

wherein the message indicating a switch to the second format of MAC subheader further indicates a sixth time point to switch;

wherein if the sixth time point is in a data transmission period, the network node resets a HARQ entity.
The method according to claim 33,

wherein the HARQ entity returns a MAC Service Data Unit (SDU) of an unacknowledged MAC Protocol Data Unit (PDU) to a layer higher than a MAC layer, before being reset.
The method according to any of claims 20 to 34, further comprising:

broadcasting (S601) about a specific Physical Random Access Channel (PRACH) resource pool preconfigured for the downstream node;

receiving (S602) a request, carrying the second format of MAC subheader, to initiate a random access to the network node.
The method according to any of claims 20 to 35, wherein a difference between the first format of MAC subheader and the second format of MAC subheader comprises a change in a format of a field.
The method according to any of claims 20 to 36, wherein the change relates to a field of Logical Channel Identifier (LC ID) and/or Logical Channel Group Identifier (LCG ID) .
The method according to any of claims 20 to 37,

wherein the downstream node comprises: a child Integrated Access Backhaul (IAB) node; and

wherein the network node comprises: a parent IAB node, or a base station.
A network node (101) , comprising:

a processor (701) ; and

a memory (702) , containing instructions executable by the processor (701) ;

wherein the network node (101) is operative to:

carry a first format of MAC subheader when initiating a random access to an upstream node of the network node;

receive, from the upstream node, a message indicating a switch to a second format of MAC subheader;

use the second format of MAC subheader to communicate with the upstream node.
The network node (101) according to claim 39, further operative to implement the method according to any of claims 2 to 19.
A network node (102) , comprising:

a processor (701) ; and

a memory (702) , containing instructions executable by the processor (701) ;

wherein the network node (102) is operative to:

receive, from a downstream node of the network node, a request carrying a first format of MAC subheader to initiate a random access;

send, to the downstream node, a message indicating a switch to a second format of MAC subheader.
The network node (102) according to claim 41, further operative to implement the method according to any of claims 21 to 38.
A computer readable storage medium (800) having a computer program (801) stored thereon, the computer program (801) executable by an apparatus to cause the apparatus to carry out the method according to any of claims 1 to 38.