Method and device for congestion control in communication network

Abstract

Embodiments of the present invention relate to a method for congestion control in a wireless telecommunication network performed by a UE (800) capable of sidelink communication, wherein one or more resource pools are allocated to the UE, the method comprising: performing (701) CBR / CR measurements on at least one of the resource pools to generate a CBR / CR value; wherein the measurements are performed on a sensing window that is preconfigured or adjusted based on the QoS of at least one packet or at least one service; and selecting (702) a resource pool or at least one resource in the resource pool based on the CBR / value and QoS requirements of the packet or service.

Description

Technical Field

[0001] The present disclosure relates to the field of wireless communications, and more particularly to congestion resolution and latency reduction in sidelink-based wireless telecommunication networks. Background Art

[0002] Admission control in the NR-Uu interface, also known as the new radio air interface between the 3rd Generation Partnership Project (3GPP) User Equipment (3GPP UE) and 5G-RAN (Radio Access Network) of a 5G network, is based on explicit bearer request and configuration signaling.

[0003] When in network control mode, the side link (SL) can use similar prior art mechanisms. In this case, before activating any V2X (Vehicle to Everything) service, the NR SL UE is configured to request the corresponding data radio bearer (DRB) from the radio base station (also called gNB in ​​5G). If the request is accepted by the radio base station, the radio base station will transmit the new bearer configuration to the UE. In the case where the channel becomes congested and there are new bearer requests, the radio base station gNB can prioritize the transmission, which is currently studied in the NR V2X study project of 3GPP Release 16 (Release 16). In this case, preemption is proposed as an extension of the URLLC (Ultra-Reliable Low Latency Communication) mechanism, i.e., URLLC services have strict requirements in terms of, for example, latency, data rate, etc.

[0004] Cellular V2X (C-V2X) will provide the foundation for vehicles to communicate with each other and everything around them, providing 360° non-line-of-sight awareness and greater predictability for enhanced road safety and autonomous driving performance.

[0005] Sidelink is an adaptation of the core 3GPP Long Term Evolution (LTE) standard that allows direct communication between two LTE devices or 5G devices without going through a radio base station or eNB or gNB. Sidelink communication may also be referred to as D2D communication, which stands for device-to-device communication.

[0006] One of the challenges that wireless networks must deal with is the congestion caused by a large number of devices and applications. 3GPP defines metrics to characterize the channel status:

[0007] CBR: (Channel Busy Rate) is defined as the fraction of subchannels in a resource pool whose Received Signal Strength Indicator (RSSI) exceeds a (pre-)configured threshold observed during a CBR measurement period of 100ms. Thus, CBR can be calculated by sensing in a fixed period of 100ms.

[0008] CR: (Channel Occupancy Rate) is evaluated at subframe n and is defined as the total number of subchannels used by the UE for its transmissions divided by the total number of configured subchannels in the transmission pool. In short, CR defines for a UE the percentage of time / frequency that the UE is able to transmit.

[0009] Existing CBR measurements may help the radio base station or gNB to avoid allocating resources to congested channels. However, indicating CBR for autonomous resource allocation mode has been proposed in previous 3GPP releases, without optimization space to enhance performance while facing congested situations. Legacy systems only allow pre-configuration of certain (pre-selected) CBR thresholds and corresponding CRs. This is valid for Mode 1 V2X communications controlled by the gNB, or for Mode 2 V2X communications that can be autonomously scheduled or assisted via network signaling, such as RRC / SIB (Radio Resource Control / System Block Information), etc. In addition, for supervised autonomous mode, i.e. Mode 2 in 3GPP V2X, coverage from network signaling can be considered. Mode 1 V2X and Mode 2 V2X are defined as follows:

[0010] Mode 1: The base station (or gNB) is configured to schedule sidelink resources to be used by the UE for sidelink transmission.

[0011] Mode 2: The UE is configured to determine (ie, the base station does not schedule) sidelink resources within the sidelink resources configured by the network / base station or the pre-configured sidelink resources.

[0012] The autonomous dispatching mode 2V2X communication follows Figure 1 The sensing procedure according to the state of the art (SoTA) is shown. Sensing is a process based on power sensing and measurement and / or based on decoded reservation information in the Sidelink Control Information (SCI). Sensing can be used for resource selection and CBR calculation.

[0013] like Figure 1 As shown, the size of the sensing window is 1000 subframes (sf). The UE continuously monitors the subframes for the duration of the sensing window. The UE checks the decoded SCI in order to check the remaining transmissions. The UE also checks the sidelink RSSI measurement. When a resource is triggered at time n (e.g. due to an incoming packet from an upper layer), potential resources or candidate resources from n+T1 to n+T2 are checked. The time period from n+T1 to n+T2 is called the resource selection window. P is the period for resource reservation.

[0014] The resource allocation granularity is T_slot, where T_slot is the NR slot duration, i.e. based on the numerology and the number of symbols in a slot (i.e. from 1 to 14). The NR slot duration is not necessarily fixed.

[0015] From the PHY layer point of view, the smallest entity that can be allocated is a resource block (RB) (plus control information, which can be distributed across time, e.g. in TDM (Time Division Multiplexing) or across frequency, e.g. in FDM (Frequency Division Multiplexing)).

[0016] Figure 1 The L subchannels in is the number of subchannels allocated for transmission in T_slot. If the MAC layer requests a sensing report from the lower layer at time slot number nth T_slot, the lower layer or PHY layer will extract the sensing window from its channel record buffer:

[0017] The response time of the PHY layer should be less than n+T1 (1 to 4 time slots)

[0018] o After the first transmission in n+T1, another scheduling or reservation may be made in n+T2.

[0019] It should be noted that T2 can be between 0 and 100 milliseconds. In LTE, T2 is between 20 and 100 T_slots.

[0020] According to the 3GPP LTE standardization and ITS standard 802.11p and ETSI (ITS103.175 version 1.1.1), it is recommended to design a mandatory decentralized congestion control (DCC) framework to keep the channel load below a certain level to avoid congestion. DCC algorithms are used to adjust one or more parameters, such as transmit power, message rate, modulation and coding scheme (MCS), and data rate, to avoid congestion. However, they all lead to trade-offs between various application requirements, such as message rate and range, which may have adverse effects on safety applications and reliability.

[0021] For example, a reduction in transmit power results in a shorter communication range and, therefore, reduced awareness of distant neighboring vehicles. It is therefore important that DCC avoids congestion while meeting application requirements.

[0022] There are other types of DCC, such as reducing the message rate; however, this may cause the transmitter side (UE side) to lose important messages (e.g., own UE TX buffer congestion). Another option is to compress more data in the same amount of resources (higher data rate / higher coding rate). This will also affect the reliability of UEs with lower SINR (signal to noise ratio) reception.

[0023] In Release 15 LTE V2X sidelink communications are based on broadcast. Advanced use cases in Release 16 New Radio (NR) require sidelink communications based on multicast. Examples of advanced use cases include vehicle platooning and advanced driving as disclosed in 3GPP Technical Report (TR) 22.886. Summary of the invention

[0024] In view of the problems disclosed previously, the present disclosure and its embodiments provide solutions to at least the following problems:

[0025] o How does the congestion resolution mechanism support NR sidelink communications with high Quality of Service (QoS) (e.g., extremely delay critical services or URLLC services) to avoid increased latency? In Release 15, the congestion resolution mechanism introduces more latency.

[0026] οHow to meet application needs while avoiding congestion?

[0027] οHow to avoid losing important messages on the transmitter side (UE side)?

[0028] o How to ensure reliability at the UE side experiencing lower SINR reception?

[0029] Therefore, the purpose of the embodiments of this document is to provide a congestion resolution mechanism that solves the above problems.

[0030] According to an aspect of the embodiments of this document, a method for congestion control performed by a UE is provided.

[0031] According to one aspect of the embodiment, a method for congestion control in a wireless telecommunication network performed by a UE includes: performing CBR / CR measurements on one or more resource pools to generate CBR / CR values, wherein the measurements are performed within a sensing period preconfigured by a network node and / or UE or adjusted based on at least QoS of at least one data packet or at least one service; based on the CBR / CR value and the QoS requirement of the at least one packet or at least one service, selecting a resource pool or at least one resource in a resource pool for transmitting the at least one packet or the at least one service.

[0032] According to an embodiment, the method comprises classifying the resource pools based on CBR / CR values.The method further comprises mapping the CBR / CR values ​​with respect to different QoS.

[0033] According to an embodiment, the method comprises: if the data packet has a high priority with respect to QoS, selecting a resource pool or a resource within a resource pool having a CBR and / or CR value below a certain threshold.

[0034] According to an embodiment, if packets are transmitted within a low minimum communication range with high QoS requirements, a resource pool or resources in a resource pool with a CBR and / or CR value below a certain threshold is selected; otherwise, if packets are transmitted within a larger and higher minimum communication range, the QoS requirements are lower.

[0035] According to an embodiment, if the data packet has a QoS profile indicating a delay requirement below a threshold, a resource pool having a CBR / CR value below a certain threshold is selected.

[0036] According to an embodiment, if a data packet has high reliability and there are multiple resource pools and the CBR / CR values ​​of the resource pools are higher than a certain threshold, data duplication is performed on the multiple resource pools.

[0037] The CBR / CR values ​​can be sorted from low CBR / CR (slight congestion) to high CBR / CR (high congestion).

[0038] According to an embodiment, if a UE is assigned to a resource pool with a high CBR / CR value and the UE starts to receive data packets or messages with high QoS, a congestion control mechanism is initiated by the following operations: requesting sidelink resource configuration and CBR reports from a network node for multiple resource pools; providing the network node with information of one or more lightly congested resource pools based on the sorted CBR / CR values; if the network node accepts the information provided by the UE, receiving a congestion control message from the network node, the congestion control message indicating information about allocated resources (F), information about allocated time periods (P), and information about time slots or transmission (T) time.

[0039] According to an embodiment, the method includes: starting a timer for extending the allocation period P based on packet QoS and / or based on QoS flow; and reducing the transmission time T if more than one time slot is allocated for each transmission opportunity; if QoS is supported, reducing the allocated frequency band of the allocated resource F by increasing the modulation and coding scheme (MSC) or the transport block size (TBS).

[0040] According to an embodiment, if there are multiple resource pools, the method includes sorting the resource pools in descending order based on CBR / CR values, and if the data packet has a higher QoS, allocating or selecting the first resource pool having the selected lowest CBR value.

[0041] According to an embodiment, the method comprises autonomously performing resource selection from a configured authorization and / or a dedicated configured authorization and / or a pre-configured resource pool.

[0042] According to an embodiment, the method comprises adjusting the sensing duration depending on a QoS profile or a QoS flow of at least one received data packet.

[0043] According to an embodiment, if the UE receives high QoS data packets in its buffer while performing CRB / CR measurements for low QoS data packets during a long sensing window, shorter sensing is triggered and the backoff timer is adjusted based on the start of the short sensing window.

[0044] According to an embodiment, the method includes: for the transmission of data packets, determining whether the medium used to transmit the data packets is busy, and if this is the case, calculating a backoff timer based on the QoS of the data packets and at least one CBR / CR value; switching to a resource pool with the lowest CBR / CR value; calculating a persistence probability P for accessing the medium based on the QoS and CBR / CR values; generating a random variable (P_val) for the persistence probability; if P is equal to P_val, transmitting the packet; otherwise, transmitting the packet with a probability of persistence equal to 100%.

[0045] According to an embodiment, a resource pool is configured for one or more bandwidth parts or one or more component carriers for sidelink transmission to one or more UEs.

[0046] According to another aspect of the embodiments of this document, there is also provided a device in the form of a UE. The UE includes instructions executable by a processor, whereby the UE includes a memory including instructions executable by the processor, so that the UE is operable to perform any subject of the above method.

[0047] A computer program comprising instructions is also provided. When executed on at least one processor of the UE, the instructions cause the at least one processor to perform any one of the above methods.

[0048] A carrier embodying a computer program, wherein the carrier is one of the following computer-readable storage media: an electronic signal, an optical signal or a radio signal.

[0049] A method performed by a radio network node (or radio base station or gNB) and an apparatus in the form of a radio network node for congestion control are also provided, wherein the gNB is configured to allocate resources to a UE to allow the UE to perform some of the steps in the above method. As will be described in detail in the detailed part of the specification, the gNB may use RRC signaling or other specific signaling, etc. to provide the necessary information for allocation including resource information and other information.

[0050] Therefore, the present disclosure includes two embodiments, in which the allocation of resources is done by the UE, or is pre-configured by the network or gNB or any suitable network node. According to the present disclosure, those skilled in the art will easily understand that the described solution is not limited to the subject matter disclosed in the present application.

[0051] An advantage of the embodiments herein is that latency is reduced or at least an increase in latency is avoided, and high reliability services with high requirements for advanced V2X use cases such as those defined in at least 3GPP Release 15 and Release 16 are supported.

[0052] Another advantage of embodiments herein is avoiding congestion while meeting application requirements in terms of QoS.

[0053] Another advantage of the embodiments herein is that it avoids the loss of important messages when transmitting messages on the transmitter side (UE side).

[0054] Another advantage of embodiments herein is to ensure reliability on the UE side with lower SINR reception. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Examples of embodiments herein and advantages of embodiments are described in more detail with reference to the accompanying drawings, in which:

[0056] Figure 1 Depicted is the SoTA sensing process for reporting and transmission.

[0057] Figure 2 Depicted is an example of CBR / CR resource ordering for congestion control according to some embodiments herein.

[0058] Figure 3 An example of QoS sorting for congestion resolution is depicted, where different communication ranges are depicted.

[0059] Figure 4 An example of resource pool access for adaptive time / day length-aware congestion control is shown, and where the CBR is fed back to the gNB by each participating UE.

[0060] Figure 5 Depicted are examples of adaptive sensing for reporting and transmission in accordance with some embodiments.

[0061] Figure 6 A flow diagram is shown relating to persistence probability for accessing a resource pool for transmission in accordance with some embodiments.

[0062] Figure 7 A flow chart of a method performed by a UE according to some exemplary embodiments herein is depicted.

[0063] Figure 8 is a block diagram depicting a UE according to exemplary embodiments herein. DETAILED DESCRIPTION

[0064] In the following, reference Figure 2-8 The detailed description of the exemplary embodiments is presented to enable easier understanding of the solutions described herein.The following abbreviations are used herein.

[0065] NR New Radio DSRC Dedicated short-range communication SLR Service Level Requirements CAM Collaborative Awareness Message DENM Decentralized Environment Notification PSCCH Physical sidelink control channel SCI Sidechain control information HARQ Hybrid Automatic Repeat Request ACK / NACK Confirmation / Negative Confirmation DMRS Demodulation Reference Signal S-RSRP Sidechain-Received Signal Strength SL Sidechain SFCI Sidechain-Feedback-Control Information

[0066] As mentioned before, in 3GPP Release 16, advanced use cases are defined in NR, such as vehicle platooning, advanced driving, and extended sensors, which will benefit from the congestion control mechanism according to the embodiments of this document.

[0067] Some advanced V2X service use cases defined for NR V2X require stringent latency, reliability, and data rates. Congestion control mechanisms are used to maintain system performance in high density scenarios. Channel Busy Rate (CBR) is used as a metric to derive traffic load and can be measured by the UE and used in congestion control mechanisms. The larger the CBR, the more congested the resource. CBR is an example of a congestion metric or congestion level.

[0068] The congestion control mechanism according to the embodiments herein may be UE assisted or controlled by the network or gNB (if available), e.g., in connection with Mode 1.

[0069] Exemplary embodiments can be divided into E1 and E2 as follows:

[0070] 1-(E1) According to an embodiment, resources are allocated to one or more resource pools having different congestion levels, wherein

[0071] a. (E1.1) QoS can be used to select among different resource pools with different congestion levels / parameters (CBR / CR or other congestion metrics).

[0072] Based on different QoS profiles or different QoS values / levels, data can be prioritized and ordered between available resource pools. Examples of QoS profiles include 5QI, which is defined as a scalar used as a reference to the 5G QoS characteristics defined in clause 5.7.4 of 3GPP TS 23.501, i.e., access node-specific parameters that control the QoS forwarding treatment of QoS flows. In clause 5.7.4 of 3GPP TS 23.501, a one-to-one mapping of the standardized 5QI to different QoS characteristics is provided in Table 5.7.4-1.

[0073] An example of a portion of Table 5.7.4-1 is presented below, which describes a one-to-one mapping of 5QI values ​​to different QoS characteristics for different service examples.

[0074]

[0075]

[0076] A QoS flow can include the following QoS profiles or QoS field metrics:

[0077] I - Communication range, step size in meters or radio distance in dB (decibels)

[0078] II-Packet Priority, Packet Delay, Packet Reliability

[0079] III- Link quality CSI / CQI (channel state information / channel quality information), RSSI, RSRP (received signal received power), RSRQ (received signal received quality), UE link establishment quality (provider-based), bearer link quality (network-based), statistical link quality history, etc.

[0080] It should be noted that the resource pool disclosed herein is valid for all broadcast types (ie, broadcast, multicast or unicast).

[0081] b. (E1.2) In case of pre-configuration (or configuration communicated by the network), one or more resource pools may be used for congestion control / resolution using a CBR value appropriate for the congestion situation by modifying the associated CR value with respect to the QoS profile. Thus, when the measured CBR exceeds the CBR threshold, one or more resource pools may be used for congestion resolution. The respective CR that the UE is allowed to access for transmission may depend on the QoS profile associated with the data packets that the UE has in the buffer.

[0082] 2. (E.2) According to an embodiment, a QoS-based sensing method may be used to generate a congestion measurement or to generate a congestion measurement report, wherein:

[0083] The adaptive sensing window and / or selection / reselection window is designed as a parameter of QoS and / or a resource pool congestion parameter. Therefore, for each QoS class based on, for example, a 5QI parameter (e.g., priority), there is an associated sensing window (CBR measurement window) having a specific associated CBR value. For example, for a transmission with a given CBR value, a high QoS may use, for example, a listen-before-talk (LBT) method to perform faster (short) sensing. The CBR measurement window may be configured by the network based at least on a QoS profile. Other factors, such as speed, previous CBR measurement history, may be considered. The CBR measurement window may be pre-configured.

[0084] As will be explained, the adaptive backoff window for the short sensing mechanism with an adaptive size may be a function of QoS and / or resource pool congestion parameters.

[0085] Additionally, CBR-based resource pool scaling may be used. Adaptive transmission or resource pool definition scaling may be a function of QoS and / or resource pool congestion parameters. Thus, once congestion is identified, the UE is configured to scale down the identified resource time / frequency resources to maintain short transmissions. Thus, the resource pool is not fixed in time and frequency. The resource pool may be extended in time and / or frequency based on QoS, may maintain short transmissions if the resource pool is congested, and may be extended in frequency but limited in time.

[0086] The adaptive persistent transmission probability may be a function of QoS and / or resource pool congestion parameters.

[0087] Consider the following assumptions:

[0088] The UE generates data packets for transmission, so the UE has one or more packets in its buffer.

[0089] The UE can receive packets from the gNB and can route these packets to another UE (as a relay or as per application layer requirements) using sidelink communication.

[0090] The UE obtains at least one configuration grant from the gNB via Radio Resource Control (RRC) signaling. The configuration indicates transmission in a certain mode on one or more resource pools.

[0091] The UE is configured to transmit autonomously on one or more resource pools.

[0092] The UE follows the pre-configuration to autonomously transmit on one or more pre-configured resource pools.

[0093] Among the available resource pools, one or more resource pools can be dedicated for congestion control.

[0094] According to an embodiment of the present invention, congestion control may be handled in operation mode 1 or operation mode 2 of the sidelink communication currently defined for NR V2X. As previously described in mode 1, the radio base station or radio network node is configured to schedule one or more sidelink resources to be used by the UE for sidelink transmission. In mode 2, the UE is configured to determine (ie, the base station does not schedule) the sidelink transmission resources among the sidelink resources configured by the base station or the network, or these resources may be pre-configured.

[0095] E1: (E1.1) QoS resource pool selection

[0096] According to this embodiment, resource pool selection is classified based on congestion level to allow for congestion control mechanisms.Examples of congestion levels are CBR and CR measurements of resource pools.

[0097] According to another embodiment, the resource pool may be identified by the network / gNB, or the resource pool may be pre-configured to the UE to handle congestion resolution.

[0098] Assume that there are one or more resource pools for transmission, wherein the UE performs CBR / CR measurements for each resource pool separately. Further assume that one or more resource pools are configured / pre-configured for congestion resolution.

[0099] Resource pools may be configured for one or more bandwidth parts (BWPs) or one or more component carriers for sidelink operation.

[0100] According to this embodiment, the UE (or gNB, if the gNB controls resource allocation) can be configured to sort the resources or resource pools in one or more BWPs in ascending or descending order based on, for example, CBR / CR measurements, as shown in the diagram depicting the groups denoted as P1, P2, P3, P4, P5, P6, ..., n in respective transmission slots. Figure 2 In the example. Figure 2 Resource pool R-Pool1, resource pool R-Pool2, ... resource pool R-Pool-K are also shown. Resource pool R-Pool1 is shown as configured in bandwidth part BWP-1; resource pool R-Pool is configured in BWP-2, and resource pool R-Pool-n is configured in BWP-K. CBR / CR->value 1 / A corresponds to the CBR / CR measurement performed on resource pool R-Pool1, CBR / CR->value 2 / A is the value corresponding to the CBR / CR measurement performed on resource pool R-Pool2, ... CBR / CR->value K / X corresponds to the CBR / CR measurement performed on resource pool R-Pool-K. K and X can take any values ​​and can be design parameters / values.

[0101] Once the data packet arrives at the UE buffer and depending on the QoS type of the data packet, an appropriate resource pool with appropriate CBR and / or CR values ​​is selected for transmission. According to some embodiments, the UE (if the UE performs distributed congestion control) or the gNB (if the gNB performs centralized congestion control) is configured to select or allocate the correct resource or resource pool based on the following metrics:

[0102] 1. Select low CBR: In this embodiment, if the data packet has a high QoS (eg important 5QI or high priority packet or minimum communication range), the data packet gets an identifier for early transmission.

[0103] High QoS packets are assigned to the first available resource pool with the lowest CBR / CR value, where CR is selected based on QoS and CBR. Mapping is required. The mapping can be defined by an upper layer or can be preconfigured. As an example, a CBR value (expressed as CBR_high_priority) less than or equal to a threshold can be assigned to a resource pool. CBR_high_priority can be set to be greater than or equal to 65%. Therefore, according to an embodiment, if a data packet has a high QoS, a resource pool with a CBR / CR value below a certain threshold is selected.

[0104] 2. Select a higher CBR: In this embodiment, if the data packet has a QoS profile for low / ultra-low latency service, or the data has a 5QI for low latency, for example, any or all resource pools with a CBR / CR value above a certain threshold are selected. As an example, a CBR / CR value greater than or equal to 65% (or greater than or equal to 70 or greater than or equal to 80) is selected, where the CR may have a high transmission probability. The latency requirement may be less than 5 milliseconds, less than 1 millisecond, or 2 milliseconds, respectively.

[0105] To this end, one or more CBR values ​​and one or more CR values ​​for different delay requirements may be defined. Examples of possible values ​​may be, for example:

[0106] -CBR_Latency_1ms CR 1

[0107] -CBR_Latency_2ms CR 2

[0108] -…

[0109] This will help ensure that transmission opportunities are available for UEs. The mapping of CBR to different CR values ​​ensures high granularity in meeting different latency requirements and channel access becomes more fairly distributed or separated among UEs.

[0110] For example, for a URLLC service with a latency requirement of, for example, 1 ms, the UE may use the channel for x ms, such as CR1. If latency is not critical, the UE may, for example, access the channel for y ms, such as CR2.

[0111] The delay requirement depends on, for example, the packet delay budget.

[0112] 3. Select multiple pools / carriers for repetition: In this embodiment, if the data packet has high reliability, the following can be applied:

[0113] a. By default, a resource pool with a CBR / CR value below a threshold may be selected. An example of a CBR / CR threshold is 60%.

[0114] b. If the CBR / CR value of a resource pool is above a certain threshold, for example, if the CBR / CR value is higher than the required value, data repetition may be performed on multiple resource pools / carriers. As an example, if the CBR value is above a threshold, such as 80%, the resource pool is almost oversubscribed, so there may be no further transmission on this resource pool. This may trigger packet data repetition on other resources or other carriers. Data repetition may occur simultaneously or continuously on different carriers / pools.

[0115] c. For data duplication, the order of resource (pool) selection can follow the CBR / CR selection criteria in 3.a and 3.b above. This means that a resource pool with a lower CBR is selected compared to other resource pools that trigger duplication.

[0116] 4. For the minimum communication range, an example of a QoS-based stepwise congestion control algorithm is given below:

[0117] The order of the following steps may be configured by the network or pre-configured. Further, the association value between the CBR and the corresponding CR may be calculated by the UE; or configured by the network or pre-configured to the UE.

[0118] For congestion control, the QoS resource pool selection E1 described above is performed in a step-by-step manner based on the QoS described in the following Algorithm I:

[0119] Assume that the UE generates data packets for transmission. Therefore, the UE has one or more data packets in its buffer.

[0120] Algorithm I:

[0121] According to the embodiment:

[0122] 1. The UE may be configured to perform CBR / CR measurements on all TX resource pools 1 to K (see Figure 2 ). Note that this step can be pre-configured or triggered by the gNB / network.

[0123] 2. The UE may be configured to analyze the QoS information of one or more data packets, and the UE may be configured to sort the packets according to the QoS categories stated earlier to assist in later transmission. The QoS categories including QoS field metrics include: communication range (step size in meters or radio distance in meters dBs); packet priority; packet delay, packet reliability; link quality based on CSI / CQI, RSSI, RSRP, RSRQ; UE link establishment quality; bearer quality and statistical link quality history.

[0124] a. If a data packet has high reliability or low latency or high priority, which means the packet has a low packet delay budget, the UE may be configured to select a resource pool specifically for the QoS class according to E1.

[0125] b. If the packet has a destination address or is allocated to a digital radio bearer (DRB) marked with a high QoS value, or is allocated to a sidelink radio bearer (SLRB) marked with a high QoS value, the UE can be configured to select a resource pool congestion resolution using the same method as high priority transmission, which is the same as Algorithm I in a.

[0126] c. If the UE cannot classify the QoS based on a priori information, the UE may be configured to classify the packet selection of the destination UE within certain communication ranges, as shown in Table 1 below:

[0127] Table 1: Example of minimum communication range and priority

[0128]

[0129] As shown in Table 1, the same UE (TX-UE0) can transmit to multiple RX-UEs (UE1, UE2, UE3...). Assume that there are multiple packets with different QoS in the buffer of TX-UE0. The transmission of higher QoS packets is transmitted to the nearest UE (RX-UE1) (shortest minimum communication range), the transmission of medium QoS packets will be transmitted to RX-UE2 (middle minimum communication range), and the data packets with low QoS are transmitted to RX-UE3 with higher minimum communication range.

[0130] Figure 3 A network scenario involving four UEs (TX-UE0, RX-UE1, RX-UE2 and RX-UE3) is shown. The communication range is also shown. Figure 3 Also shown is QoS sequencing for congestion control, which means that a UE (e.g., TX-UE0) adopts the QoS associated with the packets to be transmitted (P1, P2, P3, P4, P5, P6, ...). TX-UE0 compares the associated QoS and the congestion level (CBR), and then TX-UE0 transmits the packets sequentially from high priority to low priority.

[0131] Therefore, reference Figure 3 As shown in Table 1, if a data packet is transmitted by TX-UE0 within a low minimum communication range and the data packet has a high QoS, a resource pool or a resource within a resource pool having a CBR and / or CR value below a certain threshold is selected. Otherwise, if the data packet is transmitted within a higher minimum communication range, the QoS requirement is lower (e.g., medium or low).

[0132] Resource pool selection may be performed according to E1 described previously.

[0133] 3. The duration and period of transmission packets are selected according to the method disclosed below to disclose a resource pool access mechanism to reduce congestion, where resources can be periodically allocated to UEs with different periods, time slots and resources, the size of which depends on the QoS process described below.

[0134] Resource pool access mechanism reduces congestion

[0135] One or more resource pools may be configured, wherein at least one resource pool may be used to transmit data, and optionally, one or more resource pools may be configured to resolve congestion. In an exemplary embodiment, two pools may be only one pool used for transmission and / or for congestion resolution.

[0136] According to an embodiment, the UE is configured to measure the CBR and / or CR on each available resource pool, and the UE is configured to sort them from low CBR / CR (slightly congested) to high CBR / CR (highly congested).

[0137] If a UE is assigned to a high CBR resource pool, and the UE starts receiving high / priority QoS and / or low latency (low packet delay budget) data packets or messages, the UE may be configured to initiate a congestion control mechanism (because of these newly arrived packets) as follows:

[0138] ο In case of Mode 1 and / or Mode 2, the network-assisted congestion solution shall be:

[0139] - Sidelink active TX-UE can request new sidelink (SL) resource configuration from the network using CBR reports for multiple resource pools ordered from low to high (e.g. using CBR / CR congestion thresholds).

[0140] -The UE may suggest to the network or provide information of resource pools with light congestion to the network node by identifying resource pools with CBR / CR / any congestion threshold less than or greater than a determined / specified / (pre-)configured threshold. If the network node (or gNB) accepts the new resource pool suggestion control result, i.e., the gNB accepts the information provided by the UE, the gNB performs the following congestion control mechanism:

[0141] - Resources can be allocated to UEs periodically, which have different: period (P), time slot (T) and resource (F). The size of P, T and F depends on the QoS flow. P is the allocation period; T includes information about the time slot or transmission time, and F indicates information about the allocated resources.

[0142] - Once the UE receives its new congestion control message, i.e. in the downlink control channel information indicating P, T and F, the UE may be configured to start a timer to:

[0143] - For example for non-GBR (non-guaranteed bit rate) or lower GBR values, the period P is extended based on packet / UE QoS and QoS flow (bearer concept), where GBR is a QoS parameter. Therefore, the UE is configured to extend the allocation period P based on packet QoS and / or based on QoS flow.

[0144] - If more than one time slot is allocated per transmission opportunity (TO), the transmission time T is reduced, for example for K receive window transmissions if the reliability metric allows.

[0145] - Reduce the allocated frequency band of the allocated resource F as long as the reference symbol design is suitable, for example by increasing the MCS (Modulation and Coding Scheme) and reducing the TBS (Transport Block Size) if QoS (such as GBR) is still supported.

[0146] In Mode 2 (RRC Assisted (Active (Inactive) or UE out of coverage)) with UE-assisted congestion control / resolution, the UE may be configured to perform sensing and / or Listen Before Talk (LBT) on the existing resource pools, and the UE may be configured to sort packets based on the CBR / CR value.

[0147] Figure 4 Resource pool access for adaptive time / day length aware congestion control is shown.

[0148] Figure 4 It is shown that based on the QoS of the packets to be transmitted, the resource pool size can be adjusted in time and frequency. If the CBR level is higher, the UE will occupy less resources across the frequency and will get fewer transmission opportunities. Since there are fewer opportunities available for transmission, high priority packets are transmitted most of the time. Once the CBR level is reduced, packets can occupy more space on the frequency and can be transmitted more frequently.

[0149] E2: QoS-based sensing and backoff for congestion control (Mode 2 or Mode 1, with authorization / no authorization configured)

[0150] According to an embodiment, if the UE autonomously performs resource selection from a configured grant and / or dedicated configured pool and / or pre-configured resource pool, the following applies:

[0151] QoS-based sensing of CBR measurements can be divided into long sensing windows and short sensing windows (LBT resource selection). Sensing window and sensing interval selection can be a function of previously presented QoS profile / flow / field metrics. As an example, if the UE receives a high QoS data packet in its buffer while performing CBR / CR measurements for a low QoS data packet during a long sensing window, the UE can trigger shorter sensing and start adjusting the backoff timer based on the short sensing window.

[0152] The sensing type (long or short) may be a function of the QoS profile / flow / field identified.

[0153] According to the proposed sensing mechanism, the sensing window according to an exemplary embodiment is different for different QoS, i.e., the window size or sensing duration is a function of the QoS, e.g. for low latency the sensing window is small. This is the case, for example, if the traffic is non-periodic or is an event triggered by a message such as a DENM (Decentralized Environment Message). For high reliability, the sensing window is larger, e.g. if the traffic is regularly repeated or triggered by a CAM (Cooperative Awareness Message), such as a message that is regularly broadcast with nearby vehicles. Sensing is also different for different resource pools based on the priority of the resource pool and whether it is a congested resource pool.

[0154] The following algorithm reference Figure 5 More details about the sensing mechanism are described, Figure 5 Adaptive sensing for reporting and transmission is shown. Sensing windows and selection windows are shown.

[0155] Algorithm 2:

[0156] If packets that can contain control information meet QoS requirements, the following applies:

[0157] - The sensing window denoted as T_sensing_widow is defined based on the QoS and resource pool congestion parameters as follows:

[0158] T_sensing_window=f(QoS, resource pool congestion parameter); wherein f represents a function, and T_sensing_window∈[0…1000]T_slots.

[0159] -T1 (see Figure 5 ) is the start of transmission, i.e. the start of the selection window, which may be shorter than the time slot, based on the support of small time slots.

[0160] - T2 is the end of the selection window, which can be adjusted based on the period boundary P required for the K repetitions and the QoS of the group, i.e.

[0161] T2 = f(QoS [e.g., latency / persistence], CBR [similar to the resource pool access mechanism in Algorithm 1]).

[0162] - Once the CBR is measured or sensed during the sensing window and (re)selection of data transmission is performed / triggered, the following applies:

[0163] If the medium or system is busy and a backoff time is proposed, the backoff timer equal to BF_T is calculated based on equation XX given below:

[0164] BF_T = f(QoS, CBR / CR, Pool(x)_Congestion_Parameters) Equation - XX Otherwise perform XYZ labeling (as shown below)

[0165] If the system or medium is busy, the UE switches to the resource pool with the lowest measured CBR / CR / congestion threshold (i.e. switches to the resource pool with the lowest CBR / CR value)

[0166] If the system is idle, that is, the CBR / CR congestion threshold is less than a certain threshold (f(QoS)), continue to execute the XYZ label,

[0167] The XYZ labels are as follows:

[0168] If the probability of accessing the medium is set to P (as in equation XY), a transmission is performed with probability P, where P is given by:

[0169] P(of_TX_on_Pool(x))=f(QoS, CBR / CR, Pool(x)_Congestion_Parameters) Equation-XY

[0170] Otherwise, transmission is performed with probability P=100%.

[0171] The backoff and access probability of Pool(x) are explained below:

[0172] As shown above, the backoff timer may be calculated as given by equation XX, which is repeated below:

[0173] BF_T = f(QoS, CBR / CR, Pool(x)_Congestion_Parameters) Equation - XX

[0174] For example, for the timeout delay, the backoff timer can be between 0 and 0.5ms*P, where P is the persistence probability of accessing the resource pool for transmission, and P can be 0.25, 0.5, 0.75 or 1, with probabilities of 25% respectively. The backoff time is based on the probability P of the UE accessing the resource pool.

[0175] The backoff timers BF_T (in milliseconds) for the different QoS required by the service are as follows:

[0176] The backoff is (in milliseconds) QoS service requirements ≥0 Ultra-low latency (PDB T_p_0) T1 Low latency service (PDB T_p_1) T2 High priority service (priority, PPPP#x) T3 Short communication range (in meters) T4 High reliability service (BLER, PPPR#x) … …

[0177] The back-off timer BF_T (in milliseconds) for different CBR / CR values ​​is shown below:

[0178] The backoff is (in milliseconds) CBR / CR value, etc. ≥0 For low CBR / CR T1 For medium CBR / CR T2 For high … …

[0179] The backoff timer BF_T (in milliseconds) based on the resource pool congestion parameter is as follows:

[0180] The backoff is (in milliseconds) Resource pool congestion parameters T_max No congestion pool T_normal Normal resource pool T_min Congestion Resolution Pool … …

[0181] As mentioned previously, the probability of accessing a resource pool can be determined or calculated as follows:

[0182] P(of_TX_on_Pool(x))=f(QoS, CBR / CR, Pool(x)_Congestion_Parameters) Equation-XY

[0183] For example: if the CR of a resource pool is high (i.e., collected based on historical information about the resource pool occupancy), packets with a high PER (Packet Error Rate) will be transmitted less often. Figure 6 , which involves calculating the probability of persistent transmission (P) when P is defined or undefined. As shown in the figure, if P is defined in 601, the persistence probability P is calculated in 602 according to the equation -XY. Then, in 603, a random variable P_val is generated based on a uniform distribution. In 604, if P_val is equal to P, transmission is performed in 605, otherwise, a new P_val is generated. Therefore, transmission is performed when P_val is equal to P. Therefore, the channel here is non-contention and non-congested, and if P_val is equal to P, transmission of packets is allowed.

[0184] refer to Figure 7 , shows a flow chart of a method for performing congestion control in a wireless telecommunication network performed by a UE according to the previously described embodiment. One or more resource pools are allocated to the UE, the method comprising:

[0185] (701) performing CBR / CR measurements on the resource pool or resource pools to generate CBR / CR values, wherein the measurements are performed over a sensing window (pre-)configured by a network node (e.g. a radio base station) or the measurements are adjusted based on at least QoS of at least one data packet or at least one service; and

[0186] (702) Selecting a resource pool or at least one resource in a resource pool for transmitting at least one data packet or at least one service based on the CBR / CR value and the QoS requirement of the at least one data packet or at least one service.

[0187] Resource selection may be performed autonomously from a configured grant and / or a dedicated configured grant and / or a dedicated configured grant and / or a pre-configured resource pool.

[0188] According to an embodiment, the method further comprises classifying the resource pools based on CBR / CR values.According to an embodiment, the method comprises mapping the CBR values ​​with respect to different QoS values.

[0189] As previously described, if the data packet has a high priority with respect to QoS, a resource pool or a resource in a resource pool having a CBR and / or CR value below a certain threshold is selected. If the data packet is transmitted within a low minimum communication range with a high QoS requirement, the method includes selecting a resource pool or a resource in a resource pool having a CBR and / or CR value below a certain threshold, otherwise, if the packet is transmitted within a larger or higher communication range, the QoS requirement is lower. If the data packet has a QoS profile indicating a latency requirement below a threshold, the method includes selecting a resource pool having a CBR / CR value below a certain threshold. Examples of thresholds have been given.

[0190] If the data packet has high reliability and there are multiple resource pools allocated and the CBR / CR values ​​of the resource pools are above a certain threshold, the method includes performing or triggering data duplication on the multiple resource pools.

[0191] According to an embodiment, the method comprises ordering the CBR / CR values ​​from low CBR / CR (slight congestion) to high CBR / CR (high congestion).

[0192] According to an embodiment, if a UE is assigned to a resource pool with a high CBR / CR value and the UE starts to receive data packets or messages with high QoS, the method includes starting a congestion control mechanism by: requesting sidelink resource configuration and CBR reports from a network node for multiple resource pools; providing the network node with information of one or more lightly congested resource pools based on the sorted CBR / CR values; if the network node accepts the information provided by the UE, receiving a congestion control message from the network node, the congestion control message indicating information about allocated resources (F), information about allocation time periods (P), and information about time slots or transmission times (T).

[0193] According to an embodiment, the method also includes: starting a timer for extending the allocation period P based on packet-based QoS and / or based on QoS flow; and reducing the transmission time T if more than one time slot is allocated for each transmission opportunity; if QoS is supported, reducing the allocated frequency band of the allocated resource F by increasing the modulation and coding scheme (MSC) or the transport block size (TBS).

[0194] According to an embodiment, if there are multiple resource pools, the method comprises sorting the resource pools in descending order based on CBR / CR values, and if the data packet has a high QoS, assigning or selecting the lowest CBR value for the first available resource pool.

[0195] According to an embodiment, the method comprises adapting the sensing duration or the size of the sensing window depending on a QoS profile or a QoS flow of at least one data packet or at least one service.

[0196] As previously described, if the UE receives high QoS data packets in its buffer while performing CBR / CR measurements for low QoS data packets during a long sensing window, the method includes triggering shorter sensing and starting to adjust the backoff timer based on the short sensing window.

[0197] As described above, for the transmission of data packets, the method performed by the UE includes: determining whether the medium used to transmit the data packet is busy, and if this is the case, calculating a backoff timer based on the QoS of the data packet and at least one CBR / CR value; switching to a resource pool with the lowest CBR / CR value; calculating a persistence probability P for accessing the medium based on the QoS and the CBR / CR value; generating a random variable P_val with a persistence probability; if P is equal to P_val, transmitting the packet; otherwise, transmitting the packet with a probability of persistence equal to 100%.

[0198] According to an embodiment, once transmission begins, a congestion relation mechanism is used to monitor or supervise at least one congestion threshold (e.g., CBR / CR threshold) in order to perform adaptive transmission, which includes one or more of the following: controlling transmission rate / period, power, reducing communication range, and supplemented by QoS value.

[0199] To perform the previously described procedures or method steps in relation to a UE, some embodiments herein include a UE 800 for congestion control in a wireless telecommunication network (see Figure 8 ), wherein at least one resource pool is allocated to / from one or more resource pools for UE 800, and UE 800 includes a processor 810 and a memory 820 containing instructions executable by the processor 810, so that the UE 800 can be operated to perform any subject matter disclosed in the present application.

[0200] like Figure 8 As shown, UE 800 includes a processor 810 or a processing circuit or a processing module or a processor or a device 810; a receiver circuit or a receiver module 840; a transmitter circuit or a transmitter module 850; a memory module 820; a transceiver circuit or a transceiver module 830, which may include a transmitter circuit 850 and a receiver circuit 840. UE 800 also includes an antenna system 860. Antenna system 860 may include an antenna circuit for transmitting and receiving signals to / from at least one gNB. UE 800 is capable of sidelink or D2D communication with an object or UE in, for example, a machine 2 machine (M2M) or V2X scheme or any scheme employing sidelink communication.

[0201] UE 800 may operate in any radio access technology that supports at least sidelink communications, including 2G, 3G, 4G or LTE, LTE-A, 5G, WLAN, and WiMax, among others.

[0202] The processing module / circuit 810 includes a processor, a microprocessor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), etc., and may be referred to as a "processor 810". The processor 810 controls the operation of the UE 800 and its components. The memory (circuit or module) 820 includes a random access memory (RAM), a read-only memory (ROM), and / or another type of memory to store data and instructions that can be used by the processor 810. It should be understood that in one or more embodiments, the network node 800 includes fixed or programmed circuits configured to perform operations in any of the embodiments disclosed herein.

[0203] In at least one such example, the UE 800 includes a microprocessor, microcontroller, DSP, ASIC, FPGA, or other processing circuit configured to execute computer program instructions from a computer program stored in a non-transitory computer-readable medium located in or accessible to the processing circuit. "Non-transitory" does not necessarily mean permanent or unchanging storage, but can include storage in working memory or volatile memory, but the term does imply at least some persistence of storage. Execution of the program instructions specifically adapts or configures the processing circuit to perform the operations disclosed herein, including any of the methods disclosed herein. In addition, it will be appreciated that the UE 800 may include Figure 8 Additional components not shown.

[0204] As previously presented, the UE 800 may be operable to: perform CBR / CR measurements on one or more resource pools to generate CBR / CR values, wherein the measurements are performed over a sensing period preconfigured by the network node and / or the UE or adjusted based on at least QoS of at least one data packet or at least one service. The UE may also be operable to select a resource pool or at least one resource in a resource pool to transmit at least one data packet based on the CBR / CR value and the QoS requirement of the at least one data packet or at least one service.

[0205] The UE is also operable or configured to classify resource pools based on CBR / CR values. The UE is also configured to sort the CBR / CR measurements from low CBR / CR (slight congestion) to high CBR / CR (high congestion); and based on different quality of service, QoS, values ​​or levels.

[0206] According to another embodiment, based on the different QoS values, the UE 800 is operable to prioritize and order resources between available resources or resource pools.The UE is further configured to map CBR / CR values ​​with respect to different QoS.

[0207] If the data packet or service has a high priority with respect to QoS, the UE 00 is configured to select a resource pool or a resource within a resource pool having a CBR and / or CR value below a certain threshold.

[0208] As described above, if the data packet has a high priority with respect to QoS, a resource pool or a resource within a resource pool whose CBR and / or CR value is lower than a certain threshold is selected. If the data packet has high reliability and there are multiple resource pools, the UE 800 is configured to select a resource pool whose CBR and / or CR value is lower than a certain threshold. The UE 800 is also configured to sort the CBR / CR values ​​from low CBR / CR (mild congestion) to high CBR / CR (high congestion). If the UE 800 is assigned to a resource pool with a high CBR / CR value and the UE starts to receive packets or messages with a high QoS, the UE 800 is configured to start a congestion control mechanism by: requesting sidelink resource configuration and CBR reports from a network node for multiple resource pools; providing the network node with information of one or more lightly congested resource pools according to the sorted CBR / CR values; if the network node accepts the information provided by the UE, receiving a congestion control message from the network node, the congestion control message indicating information about allocated resources (F), information about allocated time periods (P), and information about time slots or transmission times (T). The UE 800 is configured to start a timer for extending P based on the QoS of the data packet (or service) and / or based on the QoS flow. The UE 800 is also configured to reduce the transmission time T if more than one time slot is allocated per transmission opportunity, and if QoS is supported, reduce the allocated frequency band of the allocated resource F by increasing the MSC or TBS.

[0209] Additional functions performed by UE 800 have already been disclosed and need not be repeated.

[0210] A computer program comprising instructions is also provided. When executed on at least one processor 810 of the UE, the instructions cause the at least one processor 810 to perform any of the methods disclosed in the present application.

[0211] There is also provided a carrier embodying the computer program, wherein the carrier is one of the following computer-readable storage media: an electronic signal, an optical signal or a radio signal.

[0212] A method for congestion control performed by a radio network node or radio base station or gNB is also provided, wherein the gNB allocates resources to a UE to allow the UE to perform some steps in the method disclosed in the present application. The gNB may use RRC signaling or other high-layer specific signaling, etc. to provide the necessary information, including allocated resource information and other information.

[0213] Therefore, the present disclosure includes two embodiments, wherein the allocation of resources is done or pre-configured by the UE, and / or the allocation is performed by the gNB or any suitable network node. Based on the present disclosure, those skilled in the art will easily understand that the described solution is not limited to the subject matter disclosed in this application.

[0214] There is also provided a computer program comprising instructions which, when executed on at least one processor of a network node or gNB, cause the at least one processor to perform the method steps performed by the gNB, thereby enabling a UE to control congestion in sidelink communications using adaptive resource pool access / usage assistance, such as described above.

[0215] There is also provided a carrier embodying the computer program, wherein the carrier is one of the following computer-readable storage media: an electronic signal, an optical signal or a radio signal.

[0216] As will be apparent from the detailed description, the disclosed embodiments achieve several advantages, as described below:

[0217] An advantage of the embodiments herein is that latency is reduced or at least an increase in latency is avoided, and high reliability services with high requirements for advanced V2X use cases such as those defined in at least 3GPP Release 15 and Release 16 are supported.

[0218] Another advantage of embodiments herein is that congestion is avoided while meeting application requirements.

[0219] Another advantage of embodiments herein is to avoid loss of important messages at, for example, the transmitter side (UE side).

[0220] Another advantage of embodiments herein is to ensure reliability on the UE side with lower SINR reception.

[0221] Throughout this disclosure, the words "comprise" or "comprising" have been used in a non-limiting sense, meaning "consist at least of". Although specific terms may be employed herein, they are used in a general and descriptive sense only and not for purposes of limitation. The embodiments herein may be applied in any wireless system, including GSM, 3G or WCDMA, LTE or 4G, LTE-A (or Advanced LTE), 5G, D2D, sidelink, WiMAX, WiFi, satellite communications, television broadcasting, etc., which may employ sidelink communications.

Claims

1. A method for congestion control in a wireless telecommunications network, performed by a user equipment UE (800), the method comprising: Performing measurements of a channel busy ratio CBR and a channel occupancy rate CR on one or more resource pools to generate CBR and CR values ​​(701), wherein the measurements are performed over a sensing time period preconfigured by a network node and / or the UE, and each of the one or more resource pools is configured for a bandwidth portion for sidelink transmission to one or more UEs; Based on CBR and CR values ​​and quality of service (QoS) requirements of at least one data packet, selecting at least one resource from the one or more resource pools to send the at least one data packet, wherein the at least one resource is selected from a plurality of candidate resources within an adaptive resource selection window, the adaptive resource selection window being a time period having a start time and an end time, and the end time being adaptive according to the QoS requirements of the at least one data packet (702); and If the at least one data packet has a high priority with respect to QoS, resources from the one or more resource pools having CBR and CR values ​​below a certain threshold are selected.

2. The method according to claim 1, comprising: The one or more resource pools are classified based on the CBR and CR values.

3. The method according to claim 1, comprising: The CBR value is mapped with respect to different QoS.

4. The method according to claim 1, comprising: If the packet is sent within a low minimum communication range with high QoS requirements, a resource pool or resources in a resource pool with CBR and CR values ​​below a certain threshold are selected; otherwise, if the data packet is sent within a communication range higher than the low minimum communication range, the QoS requirements are lower.

5. The method according to claim 1, comprising: If the data packet has a QoS profile indicating a latency requirement below a threshold, a resource pool having CBR and CR values ​​below a certain threshold is selected.

6. The method according to claim 1, comprising: If the data packet has high reliability and there are multiple resource pools, a resource pool having CBR and CR values ​​below a certain threshold is selected.

7. The method according to claim 1, comprising: The CBR and CR values ​​are sorted from low CBR and CR (light congestion) to high CBR and CR (heavy congestion).

8. The method according to claim 7, comprising: If the UE is allocated to a resource pool with high CBR and CR values ​​and the UE starts receiving data packets or messages with high QoS, the congestion control mechanism is initiated by the following steps: Request sidechain resource configuration and CBR reports from network nodes for multiple resource pools; providing information about one or more lightly congested resource pools to the network node according to the classified CBR and CR values; if the network node accepts the information provided by the UE, A congestion control message is received from the network node, the congestion control message indicating information about the allocated resources F, information about the allocation time P and information about the time slot or transmission time T.

9. The method according to claim 8, comprising: Start a timer for: Extending the allocated time P based on the QoS of the packet and / or based on the QoS flow; If more than one time slot is allocated to each transmitter, the transmission time T is reduced; as well as If the QoS is supported, the allocated frequency band of the allocated resource F is reduced by increasing the modulation and coding scheme MSC or the transmission block size TBS.

10. The method according to claim 1, comprising: If there are multiple resource pools, the resource pools are sorted in descending order based on the CBR and CR values, and if the data packet has a high QoS, the first available resource pool with the selected lowest CBR value is allocated or selected.

11. The method according to claim 1, further comprising: Resource selection is performed autonomously from configured permissions and / or configured dedicated permissions and / or pre-configured resource pools.

12. The method according to claim 1, comprising: The sensing duration is adapted according to a QoS profile or a QoS flow of at least one received data packet.

13. The method according to claim 1, comprising: If the UE receives high QoS data packets in its buffer while the UE is performing CBR and CR measurements during a long sensing window for low QoS data packets, shorter sensing is triggered and a backoff timer is adjusted based on the start of the short sensing window.

14. A UE (800) for congestion control in a wireless telecommunications network, the UE (800) comprising a processor (810) and a memory (820), the memory (820) containing instructions executable by the processor (810), whereby the UE (800) is operable to perform the following method: The measurement of the channel busy ratio CBR and the channel occupancy rate CR is performed on one or more resource pools to generate CBR and CR values ​​(701), wherein: performing the measurements over a sensing time period preconfigured by a network node and / or the UE, each of the one or more resource pools being configured for a bandwidth portion for sidelink transmission to one or more UEs; Based on CBR and CR values ​​and Quality of Service (QoS) requirements of at least one data packet, selecting at least one resource in one of the one or more resource pools to send the at least one data packet, wherein the at least one resource is selected from a plurality of candidate resources within an adaptive resource selection window, the adaptive resource selection window being a time period having a start time and an end time, and the end time being adaptive according to the QoS requirements of the at least one data packet (702); as well as If the at least one data packet has a high priority with respect to QoS, resources from the one or more resource pools having CBR and CR values ​​below a certain threshold are selected.

15. The UE of claim 14, wherein the UE is further operable to perform the method of any one of claims 2-13.

Images