Rate control

Abstract

The present specification describes a first apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to: receive, from a second apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; receive one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for one or more QoS flows respectively; and apply the respective recommended bit rate indicated in the one or more rate control MAC CE to the one or more QoS flows sequentially in the first ordered list of QoS flows.

Description

[0001] Rate Control

[0002] Field

[0003] Example embodiments relate user equipment, network nodes, methods and / or computer programs for use in mobile communications systems. More particularly, the example embodiments relate to rate control in mobile communications.

[0004] Background

[0005] Some mobile communication applications may dynamically adjust its data rates and / or encoding parameters to ensure a seamless and high-quality user experience, e.g. by modifying frame rates / resolution when the network is congested.

[0006] There remains a need for improvement in this field.

[0007] Summary

[0008] The scope of protection sought for various embodiments of the invention is set out by the independent claims. The embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the invention.

[0009] In a first aspect, there is described a first apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to: receive, from a second apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; receive one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for one or more QoS flows respectively; and apply the respective recommended bit rate indicated in the one or more rate control MAC CE to the one or more QoS flows sequentially in the first ordered list of QoS flows.

[0010] In some examples, the respective recommended bit rate is applied in the first order to the one or more QoS flows of the ordered list respectively.

[0011] In some examples, the first ordered list indicates an order of the QoS flows using respective indices of the QoS flows in the DRB.

[0012] In some examples, the ordered list of QoS flows is ordered based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

[0013] In some examples, the one or more QoS flows of the ordered list comprises a subset of a plurality of QoS flows of the DRB.In some examples, the instructions further cause the first apparatus to: receive an indication of a first time window for receiving the one or more rate control MAC CEs corresponding to the first ordered list of QoS flows.

[0014] In some examples, the first time window indicates a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list. In some examples, the instructions further cause the first apparatus to: start a first timer when a first rate control MAC CE is received; monitor for rate control MAC CEs corresponding to the one or more QoS flows for the duration indicated in the first time window after starting the first timer; end the first timer and stop monitoring for rate control MAC CEs when the first time window is completed. The instructions may further cause the first apparatus to: determine which of the one or more QoS flows is associated with which of the rate control MAC CEs based on a first time resolution within the first time window.

[0015] In some examples, the first time window indicates a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to each of the QoS flows of the ordered list. In some examples, the instructions further cause the first apparatus to: start a second timer when a first rate control MAC CE is received; start a subsequent second timer when a subsequent rate control MAC CE is received. In some examples, a duration of the second timer is longer than a duration of a subsequent second timer.

[0016] In some examples, the one or more rate control MAC CEs are received in one transport block, wherein the one or more rate control MAC CEs in the transport block correspond to indices based on the ordered list of QoS flows.

[0017] According to a second aspect, there is described a method, performed at a first apparatus, comprising: receiving, from a second apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; receiving one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for one or more QoS flows respectively; and applying the respective recommended bit rate indicated in the one or more rate control MAC CE to the one or more QoS flows in the first ordered list of QoS flows.

[0018] In some examples, the respective recommended bit rate is applied in the first order to the one or more QoS flows of the ordered list respectively.

[0019] In some examples, the first ordered list indicates an order of the QoS flows using respective indices of the QoS flows in the DRB.In some examples, the ordered list of QoS flows is ordered based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

[0020] In some examples, the one or more QoS flows of the ordered list comprises a subset of a plurality of QoS flows of the DRB.

[0021] In some examples, the method further comprises receiving an indication of a first time window for receiving the one or more rate control MAC CEs corresponding to the first ordered list of QoS flows.

[0022] In some examples, the first time window indicates a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list. In some examples, the method further comprises: starting a first timer when a first rate control MAC CE is received; monitoring for rate control MAC CEs corresponding to the one or more QoS flows for the duration indicated in the first time window after starting the first timer; ending the first timer and stopping monitoring for rate control MAC CEs when the first time window is completed. The method may further comprise determining which of the one or more QoS flows is associated with which of the rate control MAC CEs based on a first time resolution within the first time window.

[0023] In some examples, the first time window indicates a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to each of the QoS flows of the ordered list. In some examples, the method further comprises: starting a second timer when a first rate control MAC CE is received; starting a subsequent second timer when a subsequent rate control MAC CE is received. In some examples, a duration of the second timer is longer than a duration of a subsequent second timer.

[0024] In some examples, the one or more rate control MAC CEs are received in one transport block, wherein the one or more rate control MAC CEs in the transport block correspond to indices based on the ordered list of QoS flows.

[0025] According to a third aspect, there is provided a computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method of any preceding method definition.

[0026] According to a fourth aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing a method, comprising: receiving, from a second apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; receiving one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for one or more QoS flows respectively;and applying the respective recommended bit rate indicated in the one or more rate control MAC CE to the one or more QoS flows in the first ordered list of QoS flows.

[0027] The program instructions of the fourth aspect may also perform operations according to any preceding method definition of the second aspect.

[0028] According to a fifth aspect, there is provided an apparatus comprising: means for receiving, from a second apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; means for receiving one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for one or more QoS flows respectively; and means for applying the respective recommended bit rate indicated in the one or more rate control MAC CE to the one or more QoS flows in the first ordered list of QoS flows.

[0029] According to a sixth aspect, this specification describes an apparatus configured to perform any method as described with reference to the second aspect.

[0030] According to a seventh aspect, this specification describes an apparatus comprising: at least one processor; and at least one memory including computer program code which, when executed by the at least one processor, causes the apparatus to perform operations according to any preceding method definition of the second aspect.

[0031] According to an eighth aspect, this specification describes an apparatus comprising: a first module configured to receive, from a second apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; a second module configured to receive one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for one or more QoS flows respectively; and a third module configured to apply the respective recommended bit rate indicated in the one or more rate control MAC CE to the one or more QoS flows sequentially in the first ordered list of QoS flows.

[0032] According to a ninth aspect, this specification describes A second apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to: send, to a first apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; in response to detecting a change in one or more network performance parameters , send, to the first apparatus one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for the one or more QoS flows respectively.In some examples, the instructions further cause the second apparatus to: send, to the first apparatus, an indication of a first time window for transmission of one or more rate control MAC CEs corresponding to the first ordered list of QoS flows.

[0033] In some examples, the instructions further cause the second apparatus to configure the first time window based on at least one of network conditions or a number of QoS flows corresponding to the DRB.

[0034] In some examples, the instructions further cause the second apparatus to send information to the first apparatus indicating whether timing of the one or more MAC CEs are distributed evenly within the first time window.

[0035] In some examples, the instructions further cause the second apparatus to determine an order of QoS flows in the ordered list of QoS flows based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

[0036] In some examples, the one or more QoS flows of the ordered list comprises a subset of a plurality of QoS flows of the DRB.

[0037] In some examples, the instructions further cause the second apparatus to send, to the first apparatus, an indication of a first time resolution, wherein the time resolution indicates a duration required for transmitting rate control MAC CEs per QoS flow.

[0038] In some examples, the first time window indicates a duration for transmitting rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list, wherein the second apparatus sends the one or more rate control MAC CEs within the duration of the first time window.

[0039] In some examples, the first time window indicates a duration for transmitting rate control MAC CEs corresponding to each of the QoS flows of the ordered list.

[0040] In some examples, the one or more rate control MAC CEs are sent in one transport block, wherein the one or more rate control MAC CEs in the transport block correspond to indices based on the ordered list of QoS flows.

[0041] In some examples, the first apparatus is a user equipment (UE) and the second apparatus is a base station (gNB).

[0042] In a tenth aspect, this specification provides a method, performed at a second apparatus, comprising: sending, to a first apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; in response to detecting a change in uplink congestion, sending, to the first apparatus one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for the one or more QoS flows respectively.In some examples, the method further comprises sending, to the first apparatus, an indication of a first time window for transmission of one or more rate control MAC CEs corresponding to the first ordered list of QoS flows.

[0043] In some examples, the method further comprises configuring the first time window based on at least one of network conditions or a number of QoS flows corresponding to the DRB.

[0044] In some examples, the method further comprises sending information to the first apparatus indicating whether timing of the one or more MAC CEs are distributed evenly within the first time window.

[0045] In some examples, the method further comprises determining an order of QoS flows in the ordered list of QoS flows based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

[0046] In some examples, the one or more QoS flows of the ordered list comprises a subset of a plurality of QoS flows of the DRB.

[0047] In some examples, the method further comprises sending, to the first apparatus, an indication of a first time resolution, wherein the time resolution indicates a duration required for transmitting rate control MAC CEs per QoS flow.

[0048] In some examples, the first time window indicates a duration for transmitting rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list, wherein the second apparatus sends the one or more rate control MAC CEs within the duration of the first time window.

[0049] In some examples, the first time window indicates a duration for transmitting rate control MAC CEs corresponding to each of the QoS flows of the ordered list.

[0050] In some examples, the one or more rate control MAC CEs are sent in one transport block, wherein the one or more rate control MAC CEs in the transport block correspond to indices based on the ordered list of QoS flows.

[0051] In some examples, the first apparatus is a user equipment (UE) and the second apparatus is a base station (gNB).

[0052] According to a eleventh aspect, there is provided a computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method of any preceding method definition.

[0053] According to a twelfth aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing a method, comprising: sending, to a first apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; in response to detecting achange in uplink congestion, sending, to the first apparatus one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for the one or more QoS flows respectively.

[0054] The program instructions of the twelfth aspect may also perform operations according to any preceding method definition of the tenth aspect.

[0055] According to a thirteenth aspect, there is provided an apparatus comprising: means for sending, to a first apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; and means for, in response to detecting a change in uplink congestion, sending, to the first apparatus one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for the one or more QoS flows respectively.

[0056] According to a fourteenth aspect, this specification describes an apparatus configured to perform any method as described with reference to the tenth aspect.

[0057] According to a fifteenth aspect, this specification describes an apparatus comprising: at least one processor; and at least one memory including computer program code which, when executed by the at least one processor, causes the apparatus to perform operations according to any preceding method definition of the tenth aspect.

[0058] According to an sixteenth aspect, this specification describes an apparatus comprising: a first module configured to send, to a first apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; a second module configured to, in response to detecting a change in one or more network performance parameters, send, to the first apparatus one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for the one or more QoS flows respectively.

[0059] According to a seventeenth aspect, this specification describes a first apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to: receive, from a second apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; determine a first time window for receiving rate control messages corresponding to the first ordered list of QoS flows; receive one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for one or more QoS flows respectively; and apply the respective recommended bit rate indicated in the one or more rate control MAC CE to the one or more QoS flows sequentially in the first ordered list of QoS flows based on the first time window.In some examples, the instructions further cause the first apparatus to determine the first time window based on a function of a first time resolution and a number of the QoS flows in the ordered list, wherein the first time resolution indicates a duration between receiving each of the one or more rate control MAC CEs.

[0060] In some examples, the function is based on the equation:

[0061] time_window = t_res * (num_QFs-1);

[0062] where time_window is the first time window, t_res is the first time resolution; and num_QF is the number of QoS flows in the ordered list.

[0063] In some examples, the respective recommended bit rate is applied in the first order to the one or more QoS flows of the ordered list, respectively.

[0064] In some examples, the first ordered list indicates an order of the QoS flows using respective indices of the QoS flows in the DRB.

[0065] In some examples, the ordered list of QoS flows is ordered based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

[0066] In some examples, the one or more QoS flows of the ordered list comprises a subset of a plurality of QoS flows of the DRB.

[0067] In some examples, the first time window indicates a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list. In some examples, the instructions further cause the first apparatus to: start a first timer when a first rate control MAC CE is received; monitor for rate control MAC CEs corresponding to the one or more QoS flows for the duration indicated in the first time window upon starting the first timer; end the first timer and stop monitoring for rate control MAC CEs when the first time window is completed.

[0068] In some examples, the instructions further cause the first apparatus to: determine which of the one or more QoS flows is associated with which of the rate control MAC CEs based on a first time resolution within the first time window. In some examples, the first time window indicates a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to each of the QoS flows of the ordered list. In some examples, the instructions further cause the first apparatus to: start a second timer when a first rate control MAC CE is received; start a subsequent second timer when a subsequent rate control MAC CE is received.

[0069] In some examples, the one or more rate control MAC CEs are received in one transport block, wherein the one or more rate control MAC CEs in the transport block correspond to indices based on the ordered list of QoS flows.According to an eighteenth aspect, there is described a method, performed at a first apparatus, comprising: receiving, from a second apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; determining a first time window for receiving rate control messages corresponding to the first ordered list of QoS flows; receiving one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for one or more QoS flows respectively; and applying the respective recommended bit rate indicated in the one or more rate control MAC CE to the one or more QoS flows sequentially in the first ordered list of QoS flows based on the first time window.

[0070] In some examples, the method further comprises determining the first time window based on a function of a first time resolution and a number of the QoS flows in the ordered list, wherein the first time resolution indicates a duration between receiving each of the one or more rate control MAC CEs.

[0071] In some examples, the function is based on the equation:

[0072] time_window = t_res * (num_QFs-1);

[0073] where time_window is the first time window, t_res is the first time resolution; and num_QF is the number of QoS flows in the ordered list.

[0074] In some examples, the respective recommended bit rate is applied in the first order to the one or more QoS flows of the ordered list, respectively.

[0075] In some examples, the first ordered list indicates an order of the QoS flows using respective indices of the QoS flows in the DRB.

[0076] In some examples, the ordered list of QoS flows is ordered based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

[0077] In some examples, the one or more QoS flows of the ordered list comprises a subset of a plurality of QoS flows of the DRB.

[0078] In some examples, the first time window indicates a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list. In some examples, the instructions further cause the first apparatus to: start a first timer when a first rate control MAC CE is received; monitor for rate control MAC CEs corresponding to the one or more QoS flows for the duration indicated in the first time window upon starting the first timer; end the first timer and stop monitoring for rate control MAC CEs when the first time window is completed.In some examples, the method further comprises determining which of the one or more QoS flows is associated with which of the rate control MAC CEs based on a first time resolution within the first time window.

[0079] In some examples, the first time window indicates a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to each of the QoS flows of the ordered list. In some examples, the instructions further cause the first apparatus to: start a second timer when a first rate control MAC CE is received; start a subsequent second timer when a subsequent rate control MAC CE is received.

[0080] In some examples, the one or more rate control MAC CEs are received in one transport block, wherein the one or more rate control MAC CEs in the transport block correspond to indices based on the ordered list of QoS flows.

[0081] According to a nineteenth aspect, there is provided a computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method of any preceding method definition.

[0082] According to a twentieth aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing a method, comprising: receiving, from a second apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; determining a first time window for receiving rate control messages corresponding to the first ordered list of QoS flows; receiving one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for one or more QoS flows respectively; and applying the respective recommended bit rate indicated in the one or more rate control MAC CE to the one or more QoS flows sequentially in the first ordered list of QoS flows based on the first time window.

[0083] The program instructions of the twentieth aspect may also perform operations according to any preceding method definition of the eighteenth aspect.

[0084] According to a twenty-first aspect, there is provided an apparatus comprising: means for receiving, from a second apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; means for determining a first time window for receiving rate control messages corresponding to the first ordered list of QoS flows; means for receiving one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for one or more QoS flows respectively; and means for applying the respective recommendedbit rate indicated in the one or more rate control MAC CE to the one or more QoS flows sequentially in the first ordered list of QoS flows based on the first time window.

[0085] According to a twenty-second aspect, this specification describes an apparatus configured to perform any method as described with reference to the eighteenth aspect.

[0086] According to a twenty-third aspect, this specification describes an apparatus comprising: at least one processor; and at least one memory including computer program code which, when executed by the at least one processor, causes the apparatus to perform operations according to any preceding method definition of the eighteenth aspect.

[0087] According to an twenty-fourth aspect, this specification describes an apparatus comprising: a first module configured to receive, from a second apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; a second module configured to determine a first time window for receiving rate control messages corresponding to the first ordered list of QoS flows; a third module configured to receive one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for one or more QoS flows respectively; and a fourth module configured to apply the respective recommended bit rate indicated in the one or more rate control MAC CE to the one or more QoS flows sequentially in the first ordered list of QoS flows based on the first time window.

[0088] According to an twenty-fifth aspect, this specification describes a second apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to: send, to a first apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; in response to detecting a change in uplink congestion, send, to the first apparatus one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for the one or more QoS flows sequentially in the first ordered list of QoS flows respectively.

[0089] In some examples, the instructions further cause the second apparatus to send information to the first apparatus indicating whether timing of the one or more MAC CEs are distributed evenly within the first time window.

[0090] In some examples, the instructions further cause the second apparatus to determine an order of QoS flows in the ordered list of QoS flows based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.In some examples, the one or more QoS flows of the ordered list comprises a subset of a plurality of QoS flows of the DRB.

[0091] In some examples, the instructions further cause the second apparatus to send, to the first apparatus, an indication of a first time resolution, wherein the time resolution indicates a duration required for transmitting rate control MAC CEs per QoS flow.

[0092] In some examples, the first time window indicates a duration for transmitting rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list, wherein the second apparatus sends the one or more rate control MAC CEs within the duration of the first time window.

[0093] In some examples, the first time window indicates a duration for transmitting rate control MAC CEs corresponding to each of the QoS flows of the ordered list.

[0094] In some examples, the one or more rate control MAC CEs are sent in one transport block, wherein the one or more rate control MAC CEs in the transport block correspond to indices based on the ordered list of QoS flows.

[0095] In some examples, the first apparatus is a user equipment (UE) and the second apparatus is a base station (gNB).

[0096] According to a twenty-sixth aspect, this specification describes a method, performed at a second apparatus, comprising: sending, to a first apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; in response to detecting a change in uplink congestion, sending, to the first apparatus one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for the one or more QoS flows sequentially in the first ordered list of QoS flows respectively.

[0097] In some examples, the instructions further cause the second apparatus to send information to the first apparatus indicating whether timing of the one or more MAC CEs are distributed evenly within the first time window.

[0098] In some examples, the method further comprises determining an order of QoS flows in the ordered list of QoS flows based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

[0099] In some examples, the one or more QoS flows of the ordered list comprises a subset of a plurality of QoS flows of the DRB.

[0100] In some examples, the method further comprises sending, to the first apparatus, an indication of a first time resolution, wherein the time resolution indicates a duration required for transmitting rate control MAC CEs per QoS flow.In some examples, the first time window indicates a duration for transmitting rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list, wherein the second apparatus sends the one or more rate control MAC CEs within the duration of the first time window.

[0101] In some examples, the first time window indicates a duration for transmitting rate control MAC CEs corresponding to each of the QoS flows of the ordered list.

[0102] In some examples, the one or more rate control MAC CEs are sent in one transport block, wherein the one or more rate control MAC CEs in the transport block correspond to indices based on the ordered list of QoS flows.

[0103] In some examples, the first apparatus is a user equipment (UE) and the second apparatus is a base station (gNB).

[0104] According to a twenty-seventh aspect, there is provided a computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method of any preceding method definition according to the twenty-sixth aspect.

[0105] According to a twenty-eighth aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing a method, comprising: sending, to a first apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; in response to detecting a change in uplink congestion, sending, to the first apparatus one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for the one or more QoS flows sequentially in the first ordered list of QoS flows respectively.

[0106] The program instructions of the twenty-eighth aspect may also perform operations according to any preceding method definition of the twenty-sixth aspect.

[0107] According to a twenty-ninth aspect, there is provided an apparatus comprising: means for sending, to a first apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; means for, in response to detecting a change in uplink congestion, sending, to the first apparatus one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for the one or more QoS flows sequentially in the first ordered list of QoS flows respectively.

[0108] According to a thirtieth aspect, this specification describes an apparatus configured to perform any method as described with reference to the twenty-sixth aspect.According to a thirty-first aspect, this specification describes an apparatus comprising: at least one processor; and at least one memory including computer program code which, when executed by the at least one processor, causes the apparatus to perform operations according to any preceding method definition of the twenty-sixth aspect.

[0109] According to an thirty-second aspect, this specification describes an apparatus comprising: a first module configured to send, to a first apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; a second module configured to, in response to detecting a change in uplink congestion, send, to the first apparatus one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for the one or more QoS flows sequentially in the first ordered list of QoS flows respectively.

[0110] According to an thirty-third aspect, this specification describes a first apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to: receive, from a second apparatus, a first message indicating a first ordered list of a first plurality of quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; receive a first rate control media access control (MAC) control element (CE), wherein the first rate control MAC CE indicates a plurality of recommended bit rates in a first order for the first plurality of QoS flows respectively; and apply the respective recommended bit rates indicated in the first control MAC CE to the first plurality of QoS flows sequentially in the first ordered list of QoS flows.

[0111] In some examples, the first order corresponds to an order of QoS flows in the first ordered list of QoS flows, and the plurality of recommended bit rates are applied in the first order to the first plurality of QoS flows of the ordered list respectively.

[0112] In some examples, the first ordered list indicates an order of the QoS flows using respective indices of the QoS flows in the DRB.

[0113] In some examples, the ordered list of QoS flows is ordered based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

[0114] In some examples, the first plurality of QoS flows of the ordered list comprises a subset of a second plurality of QoS flows of the DRB.

[0115] In some examples, the instructions further cause the first apparatus to: determine which of the first plurality of QoS flows is associated with which of the plurality of recommended bit rates based on an index of the plurality of recommended bit rates.According to a thirty-fourth aspect, this specification describes a method, performed at a first apparatus, comprising: receiving, from a second apparatus, a first message indicating a first ordered list of a first plurality of quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; receiving a first rate control media access control (MAC) control element (CE), wherein the first rate control MAC CE indicates a plurality of recommended bit rates in a first order for the first plurality of QoS flows respectively; and applying the respective recommended bit rates indicated in the first control MAC CE to the first plurality of QoS flows sequentially in the first ordered list of QoS flows.

[0116] In some examples, the first order corresponds to an order of QoS flows in the first ordered list of QoS flows, and the plurality of recommended bit rates are applied in the first order to the first plurality of QoS flows of the ordered list respectively.

[0117] In some examples, the first ordered list indicates an order of the QoS flows using respective indices of the QoS flows in the DRB.

[0118] In some examples, the ordered list of QoS flows is ordered based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

[0119] In some examples, the first plurality of QoS flows of the ordered list comprises a subset of a second plurality of QoS flows of the DRB.

[0120] In some examples, the method further comprises determining which of the first plurality of QoS flows is associated with which of the plurality of recommended bit rates based on an index of the plurality of recommended bit rates.

[0121] According to a thirty-fifth aspect, there is provided a computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method of any preceding method definition of the thirty-fourth aspect.

[0122] According to a thirty-sixth aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing a method, comprising: receiving, from a second apparatus, a first message indicating a first ordered list of a first plurality of quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; receiving a first rate control media access control (MAC) control element (CE), wherein the first rate control MAC CE indicates a plurality of recommended bit rates in a first order for the first plurality of QoS flows respectively; and applying the respective recommended bit rates indicated in the first control MAC CE to the first plurality of QoS flows sequentially in the first ordered list of QoS flows.

[0123] The program instructions of the thirty-sixth aspect may also perform operations according to any preceding method definition of the thirty-fourth aspect.According to a thirty-seventh aspect, there is provided an apparatus comprising: means for receiving, from a second apparatus, a first message indicating a first ordered list of a first plurality of quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; means for receiving a first rate control media access control (MAC) control element (CE), wherein the first rate control MAC CE indicates a plurality of recommended bit rates in a first order for the first plurality of QoS flows respectively; and means for applying the respective recommended bit rates indicated in the first control MAC CE to the first plurality of QoS flows sequentially in the first ordered list of QoS flows.

[0124] According to a thirty-eighth aspect, this specification describes an apparatus configured to perform any method as described with reference to the thirty-fourth aspect.

[0125] According to a thirty-ninth aspect, this specification describes an apparatus comprising: at least one processor; and at least one memory including computer program code which, when executed by the at least one processor, causes the apparatus to perform operations according to any preceding method definition of the thirty-fourth aspect.

[0126] According to a fortieth aspect, this specification describes an apparatus comprising: a first module configured to receive, from a second apparatus, a first message indicating a first ordered list of a first plurality of quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; a second module configured to receive a first rate control media access control (MAC) control element (CE), wherein the first rate control MAC CE indicates a plurality of recommended bit rates in a first order for the first plurality of QoS flows respectively; and a third module configured to apply the respective recommended bit rates indicated in the first control MAC CE to the first plurality of QoS flows sequentially in the first ordered list of QoS flows.

[0127] According to a forty-first aspect, this specification describes a second apparatus comprising: at least one processor; and at least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to:

[0128] send, to a first apparatus, a first message indicating a first ordered list of a first plurality of quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; in response to detecting a change in uplink congestion, send, to the first apparatus, a first rate control media access control (MAC) control element (CE), wherein the first rate control MAC CE indicates a plurality of recommended bit rates in a first order for the first plurality of QoS flows sequentially in the first ordered list of QoS flows respectively.

[0129] In some examples, the instructions further cause the second apparatus to determine an order of QoS flows in the ordered list of QoS flows based on one or more of: a priority corresponding to theQoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

[0130] In some examples, the first plurality of QoS flows of the ordered list comprises a subset of a second plurality of QoS flows of the DRB.

[0131] In some examples, the first apparatus is a user equipment (UE) and the second apparatus is a base station (gNB).

[0132] According to a forty-second aspect, this specification describes a method, performed at a second apparatus, comprising: sending, to a first apparatus, a first message indicating a first ordered list of a first plurality of quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; in response to detecting a change in uplink congestion, sending, to the first apparatus, a first rate control media access control (MAC) control element (CE), wherein the first rate control MAC CE indicates a plurality of recommended bit rates in a first order for the first plurality of QoS flows sequentially in the first ordered list of QoS flows respectively.

[0133] In some examples, the method further comprises determining an order of QoS flows in the ordered list of QoS flows based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

[0134] In some examples, the first plurality of QoS flows of the ordered list comprises a subset of a second plurality of QoS flows of the DRB.

[0135] In some examples, the first apparatus is a user equipment (UE) and the second apparatus is a base station (gNB).

[0136] According to a forty-third aspect, there is provided a computer program product comprising a set of instructions which, when executed on an apparatus, is configured to cause the apparatus to carry out the method of any preceding method definition of the forty-second aspect.

[0137] According to a forty-fourth aspect, there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing a method, comprising: sending, to a first apparatus, a first message indicating a first ordered list of a first plurality of quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; in response to detecting a change in uplink congestion, sending, to the first apparatus, a first rate control media access control (MAC) control element (CE), wherein the first rate control MAC CE indicates a plurality of recommended bit rates in a first order for the first plurality of QoS flows sequentially in the first ordered list of QoS flows respectively.

[0138] The program instructions of the fourth aspect may also perform operations according to any preceding method definition of the forty-second aspect.According to a forty-fifth aspect, there is provided an apparatus comprising: means for sending, to a first apparatus, a first message indicating a first ordered list of a first plurality of quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; means for, in response to detecting a change in uplink congestion, sending, to the first apparatus, a first rate control media access control (MAC) control element (CE), wherein the first rate control MAC CE indicates a plurality of recommended bit rates in a first order for the first plurality of QoS flows sequentially in the first ordered list of QoS flows respectively.

[0139] According to a forty-sixth aspect, this specification describes an apparatus configured to perform any method as described with reference to the forty-second aspect.

[0140] According to a forty-seventh aspect, this specification describes an apparatus comprising: at least one processor; and at least one memory including computer program code which, when executed by the at least one processor, causes the apparatus to perform operations according to any preceding method definition of the forty-second aspect.

[0141] According to a forty-eighth aspect, this specification describes an apparatus comprising: a first module configured to send, to a first apparatus, a first message indicating a first ordered list of a first plurality of quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied; a second module configured to, in response to detecting a change in uplink congestion, send, to the first apparatus, a first rate control media access control (MAC) control element (CE), wherein the first rate control MAC CE indicates a plurality of recommended bit rates in a first order for the first plurality of QoS flows sequentially in the first ordered list of QoS flows respectively.

[0142] Brief Description of Drawings

[0143] Example embodiments will now be described by way of non-limiting example, with reference to the accompanying drawings, in which:

[0144] FIG. 1 is a block diagram of a system in accordance with an example embodiment;

[0145] FIG. 2 is a block diagram of an example media access control (MAC) control element (CE) in accordance with an example embodiment;

[0146] FIGs. 3 and 4 are flowcharts of algorithms in accordance with example embodiment;

[0147] FIG. 5 is a block diagram of a system in accordance with an example embodiment;

[0148] FIGs. 6 to 11 are flowcharts of algorithms in accordance with example embodiments;

[0149] FIG. 12 is a block diagram of an example media access control (MAC) control element (CE) in accordance with an example embodiment;

[0150] FIG. 13 is a message flow in accordance with an example embodiment;FIG. 14 is a schematic diagram of a system that may be used to implement one or more of the example embodiments; and

[0151] FIG. 15 shows tangible media for storing computer-readable code which when run by a computer may perform methods according to example embodiments described herein.

[0152] Detailed Description

[0153] FIG. 1 is a block diagram of an example system, indicated generally by the reference numeral 10, in accordance with an example embodiment.

[0154] System 10 shows a first apparatus 11, such as a user equipment (UE), and a second apparatus 12, such as a network node (base station or gNB). The first apparatus 11 and the second apparatus 12 may be in communication with each other via a communication channel. The communication channel may be provided by a data radio bearer (DRB) 300 that may be used for transferring various types of data, such as audio, video, files, haptic, or the like. The various types of data may be associated with a separate quality of service (QoS) flow. The DRB 300 may comprise a plurality of QoS flows 301, 302, and 303. For example, the DRB 300 may be associated with an extended reality application, and QoS flow 301 may be associated with audio data, QoS flow 302 may be associated with video data, and QoS flow 303 may be associated with haptic data.

[0155] In 3GPP RAN # 102, radio access network (RAN) involved rate control was proposed, for example, where an extended reality (XR) application may dynamically adjust its data rate and encoding parameters to ensure a seamless and high-quality user experience, e.g. by modifying frame rates / resolution when the network is congested [RP-234013].

[0156] In RAN#105, XR work in Rel-19 is continuing with a new objective on the uplink congestion handling [RP-2417711:

[0157]

[0158] One of the options for QoS flow level rate control indication is using the RRC signalling for QoS flow indication and then legacy MAC CE for rate control. The network may configure, via RRC (radio resource control ) signaling, which QoS flow is subject to rate control while MAC CE only indicates the DRB ID to which the corresponding QoS flow belongs. However, when multiple QoS flows are mapped into a single DRB, the UE may not have clear information about which QoS flow therate control is applied to, and may then apply the rate control to one or more QoS flows based on a UE-side decision. This may not be desirable.

[0159] It may be desirable to allow a gNB to perform rate control, for example, gNB indicates rate control information to the UE for each QoS flow of a DRB. A media access control (MAC) control element (CE) may be used for indicating a recommended bit rate on a DRB level. However, there is a need for further improvement in this field such that an RBR can be indicated for each QoS flow.

[0160] FIG. 2 is a block diagram of an example media access control (MAC) control element (CE), indicated generally by the reference numeral 20, in accordance with an example embodiment. The MAC CE 20 may be a rate control MAC CE comprising, for example a sub-header (not shown in the figure), a logical channel identifier (LCID) field, and a payload comprising a bit rate_1. For example, the bit rate_1 may indicate a recommended bit rate for one or more QoS flows of a DRB. This is discussed in further details below.

[0161] FIG. 3 is a flowchart of an algorithm, indicated generally by the reference numeral 30, in accordance with an example embodiment. The operations of the algorithm 30 may be performed at a first apparatus, such as a UE (e.g. UE 11).

[0162] At operation 31, the first apparatus (e.g. UE 11) may receive, from a second apparatus (e.g. gNB 12), a first message (e.g. RRC reconfiguration message) indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied. In one example, the first ordered list indicates an order of the QoS flows using respective indices of the QoS flows in the DRB. The ordered list of QoS flows may be ordered (by the second apparatus) based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus. For example, a QoS flow corresponding to video data may have a higher impact on congestion in communication between the first apparatus and second apparatus, and therefore, it may be prioritised to apply a rate control to the QoS flow corresponding to video data in order to maximize reducing congestion. In some examples, the one or more QoS flows of the ordered list comprises a subset of a plurality of QoS flows of the DRB (e.g. there may be other QoS flows of the DRB that may not be listed in the ordered list).

[0163] At operation 32, the first apparatus may receive one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate (RBR) for one or more QoS flows respectively. The first order may be an order in which the first apparatus receives the one or more rate control MAC CEs, such that this order may not be predefined, and may correspond to an order in which the second apparatus sends the rate control MAC CEs to the first apparatus. The one or more rate control MAC CEs may be of the sametype, such that only the payload of the MAC CEs may indicate same or different RBRs, while the subheader and / or LCID may remain the same.

[0164] At operation 33, the first apparatus may apply the respective recommended bit rate (RBR) indicated in the one or more rate control MAC CE to the one or more QoS flows sequentially in the first ordered list of QoS flows. The respective recommended bit rate may be applied in the first order to the one or more QoS flows of the ordered list respectively.

[0165] For example, three rate control MAC CEs are received in a first order as follows:

[0166] • MAC CE1

[0167] • MAC CE2

[0168] • MAC CE3

[0169] And the first ordered list of QoS flows is as follows:

[0170] • QoS1

[0171] • QoS3

[0172] • QoS2

[0173] Based on the first order of MAC CEs and the first ordered list of QoS flows, the first apparatus may apply RBRs to QoS flows based on the following mapping:

[0174] • RBR indicated in MAC CE1 is applied to QoS flow #1

[0175] • RBR indicated in MAC CE2 is applied to QoS flow #3

[0176] • RBR indicated in MAC CE3 is applied to QoS flow #2

[0177] In an example embodiment, the one or more rate control MAC CEs are received in one transport block (e.g. protocol data unit (PDU)), where the one or more rate control MAC CEs in the transport block correspond to indices based on the ordered list of QoS flows.

[0178] FIG. 4 is a flowchart of an algorithm, indicated generally by the reference numeral 40, in accordance with an example embodiment. The operations of the algorithm 40 may be performed at a first apparatus, such as a UE. At operation 41, the first apparatus may receive an indication of a first time window for receiving the one or more rate control MAC CEs corresponding to the first ordered list of QoS flows. In some examples, the operation 41 may be optional, such that the first apparatus may be able to determine the first time window for receiving the one or more rate control MAC CEs (determination of the first time window by the first apparatus is described in further detail with reference to FIG. 9).

[0179] For example, the first time window may indicate a duration for which the first apparatus monitors (e.g. is configured to monitor) for receiving rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list. Alternatively, the first time window may indicate a duration forwhich the first apparatus monitors for receiving rate control MAC CEs corresponding to each of the QoS flows of the ordered list. The algorithm 40 may be applied to the embodiment where the first time window indicates a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list.

[0180] Next, at operation 42, the first apparatus may start a first timer when a first rate control MAC CE is received, and may monitor, at operation 43, for rate control MAC CEs corresponding to the one or more QoS flows for the duration indicated in the first time window after starting the first timer. At operation 44, the first apparatus may then end the first timer and stop monitoring for rate control MAC CEs when the first time window is completed.

[0181] In some examples, the first apparatus may determine which of the one or more QoS flows is associated with which of the rate control MAC CEs based on a first time resolution within the first time window. Said determination may be performed based on the first order in which the MAC CEs are received, and the sequential order of the QoS flow indices in the ordered list of QoS flows. The determination or mapping of received rate control MAC CEs may be performed upon receiving the respective rate control MAC CEs. For example, a RBR indicated in a first rate control MAC CE that is received first, may be applied to a QoS flow that is listed first in the first ordered list, while the first apparatus awaits a second rate control MAC CE.

[0182] FIG. 5 is a block diagram, indicated generally by the reference numeral 50, of a system, in accordance with an example embodiment. The block diagram 50 shows a plurality of MAC CEs received with respect to time (horizontal axis).

[0183] The block diagram 50 shows a time window 51, 52, and 53 (e.g. first time window) where the duration of the first time windows are shown to be substantially similar.

[0184] In the example of FIG. 5, mapping of the MAC CEs onto the QoS flows may be as follows:

[0185] • RBR indicated in MAC CE1 is applied to QoS flow #2

[0186] • RBR indicated in MAC CE2 is applied to QoS flow #3

[0187] • RBR indicated in MAC CE3 is applied to QoS flow #1

[0188] For example, when the MAC CE1 51a is received when a first timer is not running, the first apparatus may start the first timer corresponding to the time window 51 , and during the duration of the time window 51, the first apparatus may further receive MAC CE2 51b and MAC CE3 51c. According to an ordered list of QoS flows (ordering the QoS flows as QoS flow #2, QoS flow #3, QoS flow #1) received by the first apparatus, RBRs in the MAC CEs (in the first order of 51a, 51b, 51c) may be applied to QoS flows as QoS flow #2, QoS flow #3, QoS flow #1 respectively. When the time window 51 is finished, the first apparatus may end the timer, and stop monitoring for further MAC CEs. Another time window 52 may start when the first apparatus again receives a MAC CE1 52a, and during theduration of the time window 52, the first apparatus may further receive MAC CE252b and MAC CE3 52c. Similarly, another time window 53 may start when the first apparatus again receives a MAC CE1 53a, and during the duration of the time window 52, the first apparatus may further receive MAC CE2 53b and MAC CE353c.

[0189] In an example embodiment, the UE may determine whether a received rate control MAC CE is a first one of a first order of received MAC CEs based, at least in part, on whether the rate control MAC CE is received while a timer is running, or whether the rate control MAC CE is received while no timer is running.

[0190] If the rate control MAC CE is received while no timer is running, then the rate control MAC CE may be determined to be a first one of the first order of received MAC CEs. The UE may then apply a RBR indicated in the rate control MAC CE to a first QoS flow listed in the first ordered list of QoS flows. In one example if an RBR had already been applied to the first QoS flow in the past or according to a previously received MAC CE, the UE may consider that the new rate control MAC CE is received so that a new RBR may be applied to the first QoS flow. Therefore, as MAC CE1 52a is received while no timer was running, the MAC CE1 52a may be considered to be a first one of the first order of received MAC CEs, such that the MAC CE1 52a is mapped to QoS flow #2 (first QoS flow listed in the ordered list). Similarly, as MAC CE1 53a is received while no timer was running, the MAC CE1 53a may be considered to be a first one of the first order of received MAC CEs, such that the MAC CE1 53a is mapped to QoS flow #2 (first QoS flow listed in the ordered list).

[0191] Alternatively, if the rate control MAC CE is received while a timer is running, then the rate control MAC CE is determined not to be a first one of the first order of received MAC CEs. The UE may then determine the index of the received rate control MAC CE, for example, based on how many rate control MAC CEs have been previously received since the respective timer had been started. Therefore, as MAC CE2 52b is received while a timer corresponding to the time window 52 was running, the MAC CE252b is determined not to be a first one of the first order of received MAC CEs. The index of the MAC CE2 52b is determined to be ‘second’, based on the number of MAC CEs previously received while the timer for time window 52 had been started being equal to one (MAC CE1 52a).

[0192] In one example, a rate control implemented in the time window 51 (e.g. via the rate control MAC CEs) may be applicable for a predefined time period, such that after the predefined time period and / or after receiving MAC CE1 52a, the time window 52 may start and the first apparatus may start monitoring for rate control MAC CEs again and during the duration of the time window 52, the first apparatus may further receive MAC CE2 52b and MAC CE3 52c; and after another predefined time period, and / or after receiving MAC CE1 53a, the time window 53 may start and the first apparatus maystart monitoring for rate control MAC CEs again and during the duration of the time window 53, the first apparatus may further receive MAC CE253b and MAC CE353c.

[0193] In some examples, if the first time window indicates a duration for which the first apparatus monitors (e.g. is configured to monitor) for receiving rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list, the first apparatus may starts the window when receiving a first RBR MAC CE (e.g. MAC CE1 ) and applies the RBR information to the first QoS flow in the ordered list. The first apparatus may not restart the timer corresponding to the first time window, such that a time constraint may be imposed, allowing the gNB to apply rate control to the remaining QoS flows only within a specified time (based on the time window) after initiating the rate control for a first QoS flow.

[0194] In an example embodiment, the first apparatus (UE) may receive an indication from the second apparatus (gNB) about whether timing (e.g. transmission timing) of the one or more MAC CEs are distributed evenly within the first time window. For example, if the timing is evenly distributed, and the first apparatus is aware that the timing is supposed to be evenly distributed, the first apparatus may detect if the second apparatus does not send a MAC CE for any QoS flow in the ordered list of QoS flows. For example, if there are three QoS flows listed in the ordered list, but only two MAC CEs are received, the first apparatus would be able to detect that one QoS flow is missing. For example, if a MAC CE that is supposed to be mapped to a particular QoS flow is missing, the UE may determine that an RBR in a preceding MAC CE corresponding to a QoS flow that precedes the particular QoS flow in the ordered list should be applied to the particular QoS flow.

[0195] As an example, if, in time window 51 , the MAC CE1 51 a is received, but MAC CE251 b and MAC CE351c is not received within the time window 51, the UE may apply an RBR indicated in MAC CE1 51a to QoS flows #2, #3, and #1. As such, the gNB may also utilize fewer resources as MAC CE2 and MAC CE3 may not need to be sent if the corresponding RBR is desired to be the same as that in a preceding MAC CE. Alternatively, or in addition, if, in time window 51, the MAC CE1 51a is received, but MAC CE251 b and MAC CE351 c is not received within the time window 51 , the UE may not apply any rate control to QoS flows #3 and #1, as the gNB may intend to keep the bitrate of the QoS flows #3 and #1 as a default bit rate.

[0196] In one example illustration, for a first time window of 6 milliseconds (ms) with an even time distribution (e.g. timing being evenly distributed), a first MAC CE may be received for a first QoS flow (the first QoS flow index according to the ordered list) at the start of the first time window (0 ms), a second MAC CE may be received for a second QoS flow (the second QoS flow index according to the ordered list) between Oms and 3ms from the start of the first time window, and a third MAC CE may be received for a third QoS flow (the third QoS flow index according to the ordered list) between 3msand 6ms from the start of the first time window, where 6ms from the start of the first time window may signify the end of the first time window.

[0197] In another example, for a first time window of 6 milliseconds (ms) with an even time distribution (e.g. timing being evenly distributed, such that the time resolution is 2ms), if the MAC CEs are received as follows: First MAC CE received at the start of the first time window (Oms); no MAC CEs received between Oms and 3ms; and a second MAC CEs received between 3ms and 6ms; then RBR indicated in the second MAC CE is determined to be applied to a third QoS flow of the ordered list rather than the second QoS flow of the ordered list. As there were no MAC CEs received between Oms and 3ms, the gNB may intend to not apply rate control to the second QoS flow, or may intend to apply RBR of a preceding MAC CE, such as the first MAC CE to the second QoS flow.

[0198] In another example embodiment, the first apparatus (UE) may receive an indication from the second apparatus (gNB) that the timing (e.g. transmission timing) of the one or more MAC CEs are not evenly distributed or there is no explicit or predefined timing distribution for the transmission times of the MAC CEs corresponding to the QoS flows. Alternatively, or in addition, the transmission times may not be evenly distributed, but may be distributed with specified time intervals between each MAC CE transmission. As such, the UE may map each received MAC CE in a first order of receiving sequentially to a QoS flow in the ordered list. In a scenario where the gNB does not require rate control of any QoS flow other than a QoS flow that comes last in the ordered list, the gNB may send a rate control MAC CE any time within the time window indicating a RBR which is same as an existing RBR of a respective QoS flow, such that no changes are made to the actual transmission rate. The gNB may then not need to send any rate control MAC CE for the last QoS flow, such that the transmission rate remains the same.

[0199] FIG. 6 is a flowchart, indicated generally with the reference numeral 60, in accordance with an example embodiment. In some examples, the first time window (as described above) indicates a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to each of the QoS flows of the ordered list. As such, for example, at operation 61 , when a first rate control MAC CE is received while a second timer or any other timer is not running, the first apparatus may start the second timer . At operation 62, the first apparatus may start a subsequent second timer when a subsequent rate control MAC CE is received. As such each time a rate control MAC CE is received, the first apparatus restarts the time window. In some examples, this approach may allow the gNB sufficient time for transmitting a rate control MAC CE if required for each of the QoS flows without a time restraint, as described above. For example, when a new timer starts, the gNB may determine, within the time window, whether the rate control is required for the next QoS flow after initiating the rate control for the previous QoS flow. A rate control may not be required if the RBR is supposed tobe the same as an RBR of a previous QoS flow or if the RBR is supposed to be same as a default RBR. As such, the gNB may have sufficient time to decide whether or not a rate control MAC CE is required to be sent for a particular QoS flow.

[0200] In some examples, a duration of the second timer is longer than a duration of a subsequent second timer. For example, an effect of decreasing a bit rate for a first QoS flow on the ordered list may be higher than an effect of decreasing a bit rate for a subsequent QoS flow, especially in a scenario where a QoS flow (e.g. video) having a higher bit rate is ordered as a first QoS flow in the ordered list. As discussed above, the gNB may set the order of video flow higher than the audio flow since video has a higher bit rate compared to audio flow and there can be greater potential of reduction in the bit rate for video flow. As such, for any subsequent rate control MAC CEs, it may be desirable for the UE to wait a shorted time period for the MAC CEs and save resources accordingly.

[0201] FIG. 7 is a flowchart of an algorithm, indicated generally by the reference numeral 70, in accordance with an example embodiment. The operations of the algorithm 70 may be performed at a second apparatus, such as a base station (gNB).

[0202] At operation 71, the second apparatus may send, to a first apparatus, a first message (e.g. RRC reconfiguration message) indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied. Next, at operation 72, in response to detecting a change in one or more network performance parameters, the second apparatus may send, to the first apparatus one or more rate control MAC CEs in a first order. The one or more rate control MAC CEs may indicate a recommended bit rate for the one or more QoS flows in the first ordered list respectively.

[0203] In an example embodiment, the second apparatus may determine an order of QoS flows in the ordered list of QoS flows based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus. For example, as described above, a QoS flow corresponding to video data may have a higher impact on congestion in communication between the first apparatus and second apparatus, and therefore, a QoS flow corresponding to video data may be highest in order in the ordered list of QoS flows, such that a rate control is applied to the QoS flow corresponding to video data in order to maximize reducing congestion.

[0204] Alternatively, or in addition, the order of QoS flows in the ordered list of QoS flows may be arbitrarily based on QoS flow indexes, and may not be dependent on a priority, type, or impact of the QoS flows on the congestion, no priority for QoS flows is specified by the gNB and instead QoS flows are listed according to the values of their indices in the DRB for example in a descending / ascendingorder. For example, if the ordered list is as follows [QF1, QF2, QF3], and then the rate control MAC CE may be applied accordingly:

[0205] MAC CE1 -> QF1

[0206] MAC CE2 -> QF2

[0207] MAC CE3 -> QF3

[0208] In an example embodiment, the one or more QoS flows of the ordered list comprises a subset of a plurality of QoS flows of the DRB. For example, the DRB may comprise one or more QoS flows that may not be included in the ordered list (e.g. due to no rate control being required or desired to be applied).

[0209] In some examples, the one or more rate control MAC CEs are sent in one transport block (PDU). The one or more rate control MAC CEs in the transport block may correspond to indices based on the ordered list of QoS flows.

[0210] In an example illustration, three QoS flows may be mapped to a single DRB, such that the ordered list of QoS flows may be generated by the gNB such that the existing order of QoS flows in the DRB such as [QF1, QF2, QF3] = [haptic, video, audio] is re-ordered to [QF2, QF3, QF1] = [video, audio, haptic]. For example, the reordering may be based on a priority, a QoS flow type, or an impact of the QoS flow on overall congestion. In this case, QF2 is the first in the QoS flow list since the video flow may have a significantly high bit rate initially, and therefore may offer more reduction of bit rate which may help more with the relieving of congestion. Similarly, haptic feedback is last in the QoS flow list for rate control as its impact on overall rate control may be insubstantial. For example, if no rate control needs to be applied for the QoS flow with the haptic feedback, the gNB may not send a MAC CE for haptic flow. Alternatively, QoS flow list may include only [QF2, QF3], i.e., without QF1, since haptic feedback may not help much in relieving the congestion.

[0211] In some examples, if the gNB determines that the uplink bit rate needs to be adjusted for multiple QoS flows, the UE may receive multiple RBR MAC CEs in one transport block at the same time. In this case, the UE may apply the MAC CEs in the order of the QoS flows listed in the ordered list of QoS flows.

[0212] FIG. 8 is a flowchart of an algorithm, indicated generally by the reference numeral 80, in accordance with an example embodiment. The operations of the algorithm 80 may be performed at a second apparatus, such as a base station (gNB).

[0213] At operation 81 , the second apparatus may configure the first time window based on at least one of network conditions or a number of QoS flows corresponding to the DRB. Next, at operation 82, the second apparatus may send, to the first apparatus, an indication of a first time window for transmission of one or more rate control MAC CEs corresponding to the first ordered list of QoS flows.At operation 83, the second apparatus may send, to the first apparatus, an indication of a first time resolution, wherein the time resolution indicates a duration required for transmitting rate control MAC CEs per QoS flow. Alternatively, or in addition, the second apparatus may send information to the first apparatus indicating whether timing of the one or more MAC CEs are distributed evenly within the first time window. For example, if the timing of the one or more MAC CEs are distributed evenly, then the first apparatus may calculate the time resolution based on the total duration of the time window divided by the number of QoS flows.

[0214] In some examples, the indication of the first time window and / or the indication of the first time resolution may be sent in a same first message (RRC reconfiguration message) as the ordered list of QoS flows, or may be sent separately another message (e.g. RRC reconfiguration message).

[0215] In an example embodiment, as described briefly above, the first time window may indicate a duration for transmitting rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list. In this scenario, the second apparatus may send the one or more rate control MAC CEs within the duration of the first time window.

[0216] In an alternative embodiment, the first time window indicates a duration for transmitting rate control MAC CEs corresponding to each of the QoS flows of the ordered list, such that the first apparatus restarts a timer every time a rate control MAC CE is received.

[0217] FIG. 9 is a flowchart of an algorithm, indicated generally by the reference numeral 90, in accordance with an example embodiment. The operations of the algorithm 90 may be performed at a first apparatus, such as a UE.

[0218] At operation 91 (similar to operation 31), the first apparatus may receive, from a second apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied.

[0219] Next, at operation 92, the first apparatus may determine a first time window for receiving rate control messages corresponding to the first ordered list of QoS flows. For example, the first time window may indicate a duration for which the first apparatus monitors (e.g. is configured to monitor) for receiving rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list. Alternatively, the first time window may indicate a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to each of the QoS flows of the ordered list.

[0220] In an example embodiment, the first apparatus may determine the first time window based on a function of a first time resolution and a number of the QoS flows in the ordered list, wherein the first time resolution indicates a duration between receiving each of the one or more rate control MAC CEs. For example, the function is based on the equation:

[0221] time_window = t_res * (num_QFs-1);where time_window is the first time window, t_res is the first time resolution; and num_QF is the number of QoS flows in the ordered list.

[0222] Next, at operation 93 (similar to operation 32), the first apparatus may receive one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for one or more QoS flows respectively. The first apparatus may then apply, at operation 94 (similar to operation 33), the respective recommended bit rate indicated in the one or more rate control MAC CE to the one or more QoS flows sequentially in the first ordered list of QoS flows based on the first time window.

[0223] In an example embodiment, the equation used for determining the time window may be implemented with the following steps:

[0224] • UE, upon reception for the QoS flow list subtracts one from the total number of QoS flows.

[0225] • It then multiplies the result of step 1 with the pre-known time resolution to determine the time window.

[0226] • Upon reception of a first MAC CE, UE starts the timer for the determined time window.

[0227] • UE then receives further rate control MAC CEs according to the time resolution and applies those to the corresponding QoS flows in the list until the time window expires.

[0228] In some examples, if the first time window indicates a duration for which the first apparatus monitors (e.g. is configured to monitor) for receiving rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list, then the operations of algorithm 40 (excluding operation 41) may be performed by the first apparatus based on a first time window is determined by the first apparatus.

[0229] In some examples, if the first time window (as described above) indicates a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to each of the QoS flows of the ordered list, then the operations of algorithm 60 may be performed by the first apparatus based on a first time window is determined by the first apparatus.

[0230] In some examples, when the UE is configured to determine a time window, the operations of algorithm 80 may be performed (excluding the configuring of the first time window by the second apparatus).

[0231] FIG. 10 is a flowchart of an algorithm, indicated generally by the reference numeral 100, in accordance with an example embodiment. The operations of the algorithm 90 may be performed at a first apparatus, such as a UE.

[0232] At operation 101 (similar to operation 31), the first apparatus may receive, from a second apparatus, a first message indicating a first ordered list of a first plurality of quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied.Next, at operation 102, the first apparatus may receive a first rate control media access control (MAC) control element (CE). The first rate control MAC CE may indicate a plurality of recommended bit rates in a first order for the first plurality of QoS flows respectively. The first control rate MAC CE may therefore be different than a legacy MAC CE.

[0233] The first apparatus may then apply, at operation 103, the respective recommended bit rates indicated in the first control MAC CE to the first plurality of QoS flows sequentially in the first ordered list of QoS flows.

[0234] In some examples, the first order in which the RBRs are comprised in the rate control MAC CEs may correspond to an order of QoS flows in the first ordered list of QoS flows. The plurality of recommended bit rates may then be applied in the first order to the first plurality of QoS flows of the ordered list respectively.

[0235] As described earlier, the first ordered list indicates an order of the QoS flows using respective indices of the QoS flows in the DRB. The ordered list of QoS flows is ordered based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

[0236] In some examples, the first apparatus may determine which of the first plurality of QoS flows is associated with which of the plurality of recommended bit rates based on an index of the plurality of recommended bit rates.

[0237] FIG. 11 is a flowchart of an algorithm, indicated generally by the reference numeral 110, in accordance with an example embodiment. The operations of the algorithm 90 may be performed at a second apparatus, such as a base station (gNB).

[0238] At operation 111 , the second apparatus may send, to a first apparatus, a first message indicating a first ordered list of a first plurality of quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied. Next, at operation 112, in response to detecting a change in uplink congestion, the second apparatus may send, to the first apparatus, a first rate control media access control (MAC) control element (CE). The first rate control MAC CE may indicate a plurality of recommended bit rates in a first order for the first plurality of QoS flows sequentially in the first ordered list of QoS flows respectively. The first control rate MAC CE may therefore be different than a legacy MAC CE.

[0239] In some examples, the first order in which the RBRs are comprised in the rate control MAC CEs may correspond to an order of QoS flows in the first ordered list of QoS flows. The plurality of recommended bit rates may then be applied by the first apparatus in the first order to the first plurality of QoS flows of the ordered list respectively.As described earlier, the first ordered list indicates an order of the QoS flows using respective indices of the QoS flows in the DRB. The ordered list of QoS flows is ordered by the second apparatus based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

[0240] FIG. 12 is a block diagram of an example media access control (MAC) control element (CE), indicated generally by the reference numeral 120, in accordance with an example embodiment. The MAC CE 120 may be a rate control MAC CE comprising, for example a sub-header (not shown in the figure), a logical channel identifier (LCID) field (octet 1), and a payload comprising a plurality of recommended bit rates (RBRs) corresponding to a plurality of QoS flows respectively. The plurality of RBRs are shown to be arranged in a first order as follows: bit rate_1; bit rate_2; bit rate_3. In an example of the first ordered list of QoS flows, the order of the QoS flows are as follows: QoS flow #2 (QF2), QoS flow #3 (QF3), QoS flow #1 (QF1 ). The RBRs in the MAC CE 120 may then be applied as: Bit Rate_1 applied to QF 2, Bit Rate_2 applied to QF 3 and Bit Rate_3 applied to QF 1.

[0241] FIG. 13 is a message flow, indicated by the reference numeral 130, in accordance with an example embodiment. The message flow 130 is between UE 131, gNB 132, and a core network module 133.

[0242] In one example, an RRC connection (e.g. normal RRC connection) may be established at operation 134 between the UE 131 and the GNB 132. Next, the gNB 132 gets information at operation 135, either from the CN 133 or the UE 131 , on which QoS flows can be throttled.

[0243] At operation 136, gNB 132 triggers an RRCReconfiguration, for example by sending a first message to the UE 131 , which may include: a priority-based list of QoS flows to which the rate control is to be applied; and optionally a time-window during which consecutive rate control MAC CEs will be received for rate control of individual QoS flows; and optionally a time resolution per QoS flow . In some examples, instead of a time resolution, the first message may further include an indication (e.g. one bit indication) of whether timing of MAC CEs distributed evenly or whether the timing of MAC CEs not distributed evenly.

[0244] Next, at operation 137, the UE 131 may start UL data transmission for all the QoS flows with initial bit rate values.

[0245] In some examples, the gNB 132 detects, at operation 138, a change of situation related to congestion e.g. congestion starts or stops or an increase / decrease in congestion in the network in the UL direction.

[0246] Next, at operation 139, the gNB 132 sends a rate control MAC CE indicating a specific bit rate value, wherein the specific bit rate an RBR as described above (e.g. RBR may be recommended bit rate that is suitable for alleviating a congestion situation).At operation 140, the UE 131 , in response to receiving the rate control MAC CE from the gNB 132, applies the RBR to the first QoS flow in the list and starts the timer for receiving more MAC CEs for other QoS flows in the list, and applying consecutive RBRs sequentially to the QoS flows in the list of QoS flows (e.g. priority based list).

[0247] At operation 141, the gNB 132 sends further rate control MAC CEs for more QoS flows in the list of QoS flows.

[0248] At operation 142, the UE 131 continues applying the subsequent MAC-CEs to the QoS flows in the list until, for example, a timer (e.g. first timer, second timer) expires (e.g. timer may be based on a time window or time resolution).

[0249] In some examples, if the UE 131 misses a MAC CE in the specified time window (e.g. configured at operation 136), the UE 131 may assumes that there was no rate control for the respective QoS flow. The UE 131 may continue, at operation 143, uplink data transmission for all the QoS flows with the updated bit rate values.

[0250] The example embodiments above propose techniques for performing the rate control of individual QoS flows within a DRB using the legacy recommended bit rate MAC CE, and ensuring overall improvement in congestion.

[0251] The invention provides a solution for QoS flow level rate control of multiple QoS flows in a DRB without any impact to the rate control MAC CE design as one solution and another with minimal impact and without the need for repetitive transmission of MAC CEs for the rate control of multiple QoS flows.

[0252] Example Apparatus

[0253] FIG. 14 shows an apparatus according to some example embodiments, which may comprise the user terminal 150. The user equipment may be, for example a smartphone, or other terminal device. The apparatus may be configured to perform the operations described herein, for example operations described with reference to any disclosed process. The apparatus comprises at least one processor 102 and at least one memory 154 directly or closely connected to the processor. The memory 104 includes at least one random access memory (RAM) and at least one read-only memory (ROM). Computer program code (software) 155 is stored in the ROM. The apparatus may be connected to a transmitter (TX) and a receiver (RX). The apparatus may, optionally, be connected with a user interface (Ul) for instructing the apparatus and / or for outputting data. The at least one processor 152, with the at least one memory 104 and the computer program code 155 are arranged to cause the apparatus to at least perform at least the method according to any preceding process, for example as disclosed in relation to the flow diagrams of FIGS. 3 to 5, 13 to 14 and related features thereof.FIG. 15 shows a non-transitory media 160 according to some embodiments. The non-transitory media 160 is a computer readable storage medium. It may be e.g. a CD, a DVD, a USB stick, a blue ray disk, etc. The non-transitory media 160 stores computer program code, causing an apparatus to perform the method of any preceding process for example as disclosed in relation to the flow diagrams and related features thereof.

[0254] Names of network elements, protocols, and methods are based on current standards. In other versions or other technologies, the names of these network elements and / or protocols and / or methods may be different, as long as they provide a corresponding functionality. For example, embodiments may be deployed in 2G / 3G / 4G / 5G networks and further generations of 3GPP but also in non-3GPP radio networks such as WiFi.

[0255] A memory may be volatile or non-volatile. It may be e.g. a RAM, a SRAM, a flash memory, a FPGA block ram, a DCD, a CD, a USB stick, and a blue ray disk.

[0256] If not otherwise stated or otherwise made clear from the context, the statement that two entities are different means that they perform different functions. It does not necessarily mean that they are based on different hardware. That is, each of the entities described in the present description may be based on a different hardware, or some or all of the entities may be based on the same hardware. It does not necessarily mean that they are based on different software. That is, each of the entities described in the present description may be based on different software, or some or all of the entities may be based on the same software. Each of the entities described in the present description may be embodied in the cloud.

[0257] Implementations of any of the above described blocks, apparatuses, systems, techniques or methods include, as non-limiting examples, implementations as hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof. Some embodiments may be implemented in the cloud.

[0258] It is to be understood that what is described above is what is presently considered the preferred embodiments. However, it should be noted that the description of the preferred embodiments is given by way of example only and that various modifications may be made without departing from the scope as defined by the appended claims.

Claims

- 34 - Claims1. A first apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the first apparatus to:receive, from a second apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied;receive one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for one or more QoS flows respectively; andapply the respective recommended bit rate indicated in the one or more rate control MAC CE to the one or more QoS flows sequentially in the first ordered list of QoS flows.

2. A first apparatus as claimed in claim 1 , wherein the respective recommended bit rate is applied in the first order to the one or more QoS flows of the ordered list respectively.

3. A first apparatus as claimed in any one of the preceding claims, wherein the first ordered list indicates an order of the QoS flows using respective indices of the QoS flows in the DRB.

4. A first apparatus as claimed in any one of the preceding claims, wherein the ordered list of QoS flows is ordered based on one or more of: a priority corresponding to the QoS flows, a type of QoS flows, or impact of the QoS flows on congestion in communication between the first apparatus and the second apparatus.

5. A first apparatus as claimed in any one of the preceding claims, wherein the instructions further cause the first apparatus to: receive an indication of a first time window for receiving the one or more rate control MAC CEs corresponding to the first ordered list of QoS flows.

6. A first apparatus as claimed in claim 5, wherein the first time window indicates a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to all of the one or more QoS flows of the ordered list.- 35 - 7. A first apparatus as claimed in claim 6, wherein the instructions further cause the first apparatus to:start a first timer when a first rate control MAC CE is received;monitor for rate control MAC CEs corresponding to the one or more QoS flows for the duration indicated in the first time window after starting the first timer;end the first timer and stop monitoring for rate control MAC CEs when the first time window is completed.

8. A first apparatus as claimed in claim 7, wherein the instructions further cause the first apparatus to: determine which of the one or more QoS flows is associated with which of the rate control MAC CEs based on a first time resolution within the first time window.

9. A first apparatus as claimed in claim 5, wherein the first time window indicates a duration for which the first apparatus monitors for receiving rate control MAC CEs corresponding to each of the QoS flows of the ordered list.

10. A first apparatus as claimed in claim 9, wherein the instructions further cause the first apparatus to:start a second timer when a first rate control MAC CE is received;start a subsequent second timer when a subsequent rate control MAC CE is received.

11. A first apparatus as claimed in claim 10, wherein a duration of the second timer is longer than a duration of a subsequent second timer.

12. A first apparatus as claimed in any one of the preceding claims, wherein the one or more rate control MAC CEs are received in one transport block, wherein the one or more rate control MAC CEs in the transport block correspond to indices based on the ordered list of QoS flows.

13. A second apparatus comprising:at least one processor; andat least one memory storing instructions that, when executed by the at least one processor, cause the second apparatus to:send, to a first apparatus, a first message indicating a first ordered list of one or more quality of service (QoS) flows of a data radio bearer (DRB) to which a rate control is to be applied;in response to detecting a change in one or more network performance parameters , send, to the first apparatus one or more rate control media access control (MAC) control element (CE) in a first order, wherein the one or more rate control MAC CE indicates a recommended bit rate for the one or more QoS flows respectively.

14. A second apparatus as claimed in claim 13, wherein the instructions further cause the second apparatus to: send, to the first apparatus, an indication of a first time window for transmission of one or more rate control MAC CEs corresponding to the first ordered list of QoS flows.

15. A second apparatus as claimed in claim 14, wherein the instructions further cause the second apparatus to configure the first time window based on at least one of network conditions or a number of QoS flows corresponding to the DRB.

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