WO2021028548A1

WO2021028548A1 - User device for wireless communication

Info

Publication number: WO2021028548A1
Application number: PCT/EP2020/072799
Authority: WO
Inventors: Thomas Fehrenbach; Baris GÖKTEPE; Cornelius Hellge; Thomas Wirth; Thomas Schierl; Nithin SRINIVASAN
Original assignee: Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Current assignee: Fraunhofer Gesellschaft zur Foerderung der Angewandten Forschung eV
Priority date: 2019-08-14
Filing date: 2020-08-13
Publication date: 2021-02-18
Anticipated expiration: 2022-02-14
Also published as: KR20220071188A; US20220232634A1; CN114342544A

Abstract

A user device, UE, for a wireless communication system according to an embodiment is provided. A backoff rule is stored within a storage of a base station and within a storage of the user device. Or, the user device is to transmit the backoff rule to the base station. Or, the user device is to receive the backoff rule from the base station. The user device is to determine a random backoff counter depending on the backoff rule. Moreover, the user device is to decrement the random backoff counter if a transmission channel is not occupied for a certain duration. Furthermore, the user device is to transmit a data packet via the transmission channel, if the random backoff counter reaches a predefined value.

Description

USER DEVICE FOR WIRELESS COMMUNICATION

Description

The present application concerns the field of wireless communication systems or networks, more specifically, enhancements or improvements in the communication among entities of the wireless communication network. Embodiments concern enhancements or improvements for NR-U (New Radio in Unlicensed Spectrum) which are random number generator related according to the provided new and inventive concepts.

Fig. 1 is a schematic representation of an example of a terrestrial wireless network 100 including, as is shown in Fig. 1(a), a core network 102 and one or more radio access networks RANi, RAN₂, ... RANN. Fig. 1(b) is a schematic representation of an example of a radio access network RAN_n that may include one or more base stations gNBi to gNBs, each serving a specific area surrounding the base station schematically represented by respective cells 106i to 106d. The base stations are provided to serve users within a cell. The one or more base stations may serve users in licensed and/or unlicensed bands. The term base station, BS, refers to a gNB in 5G networks, an eNB in UMTS/LTE/LTE-A/ LTE- A Pro, or just a BS in other mobile communication standards. A user may be a stationary device or a mobile device. The wireless communication system may also be accessed by mobile or stationary loT devices which connect to a base station or to a user. The mobile devices or the loT devices may include physical devices, ground based vehicles, such as robots or cars, aerial vehicles, such as manned or unmanned aerial vehicles (UAVs), the latter also referred to as drones, buildings and other items or devices having embedded therein electronics, software, sensors, actuators, or the like as well as network connectivity that enables these devices to collect and exchange data across an existing network infrastructure. The example is not limited to terrestrial wireless networks, but network entities can involve non-terrestrial networks (NTN), where a parts of a BS, and/or BS and/or core network can be payload of a satellite (LEO, GEO, MEO) or high altitude platform (HAPs), e.g. balloon or special airplane.

Fig. 1(b) shows an exemplary view of five cells, however, the RAN_n may include more or less such cells, and RAN_n may also include only one base station. Fig. 1(b) shows two users UEi and UE2, also referred to as user equipment, UE, that are in cell 106₂ and that are served by base station gNB₂. Another user UE₃ is shown in cell 106₄ which is served by base station gNB₄. The arrows IO8₁, 108₂ and IO8₃ schematically represent uplink/downlink connections for transmitting data from a user UEi, UE₂ and UE₃ to the base stations gNB₂, gNB₄ or for transmitting data from the base stations gNB₂, gNB to the users UEi, UE₂, UE₃. This may be realized on licensed bands or on unlicensed bands. Further, Fig. 1(b) shows two loT devices 110i and 110₂ in cell IO6₄, which may be stationary or mobile devices. The loT device 110i accesses the wireless communication system via the base station gNB4 to receive and transmit data as schematically represented by arrow 112i. The loT device 11O2 accesses the wireless communication system via the user UE3 as is schematically represented by arrow 112₂. The respective base station gNBi to gNBs may be connected to the core network 102, e.g. via the S1 interface, via respective backhaul links 114i to 114s, which are schematically represented in Fig. 1(b) by the arrows pointing to “core”. The core network 102 may be connected to one or more external networks. Further, some or all of the respective base station gNBi to gNBs may connected, e.g. via the S1 or X2 interface or the XN interface in NR, with each other via respective backhaul links 1161 to 1165, which are schematically represented in Fig. 1(b) by the arrows pointing to “gNBs”. The network can also contain UEs communicating in direct mode, also referred to as device-to- device (D2D) communication. This interface is often referred to as PC5 interface.

For data transmission a physical resource grid may be used. The physical resource grid may comprise a set of resource elements to which various physical channels and physical signals are mapped. For example, the physical channels may include the physical downlink, uplink and sidelink shared channels (PDSCH, PUSCH, PSSCH) carrying user specific data, also referred to as downlink, uplink and sidelink payload data, the physical broadcast channel (PBCH) carrying for example a master information block (MIB) and a system information block (SIB), the physical downlink, uplink and sidelink control channels (PDCCH, PUCCH, PSCCH) carrying for example the downlink control information (DCI), the uplink control information (UCI) and the sidelink control information (SCI). For the uplink, the physical channels may further include the physical random access channel (PRACH or RACH) used by UEs for accessing the network once a UE synchronized and obtained the MIB and SIB. The sidelink can also comprise the physical sidelink feedback channel (PSFCH). The physical signals may comprise reference signals or symbols (RS), synchronization signals and the like. The resource grid may comprise a frame or radio frame having a certain duration in the time domain and having a given bandwidth in the frequency domain. The frame may have a certain number of subframes of a predefined length, e.g. 1ms. Each subframe may include one or more slots of 12 or 14 OFDM symbols depending on the cyclic prefix (CP) length. A frame may also consist of a smaller number of OFDM symbols, e.g. when utilizing shortened transmission time intervals (sTTI) or a mini-slot/nonslot-based frame structure comprising just a few OFDM symbols.

The wireless communication system may be any single-tone or multicarrier system using frequency-division multiplexing, like the orthogonal frequency-division multiplexing (OFDM) system, the orthogonal frequency-division multiple access (OFDMA) system, or any other IFFT-based signal with or without CP, e.g. DFT-s-OFDM. Other waveforms, like non- orthogonal waveforms for multiple access, e.g. filter-bank multicarrier (FBMC), generalized frequency division multiplexing (GFDM) or universal filtered multi carrier (UFMC), may be used. The wireless communication system may operate, e.g., in accordance with the LTE- Advanced pro standard, or the 5G or NR, New Radio, standard, or the NR-U, New Radio Unlicensed, standard, or the 802.11 ax, or the 802.11 be. rules

The wireless network or communication system depicted in Fig. 1 may by a heterogeneous network having distinct overlaid networks, e.g., a network of macro cells with each macro cell including a macro base station, like base station gNBi to gNBs, and a network of small cell base stations (not shown in Fig. 1), like femto or pico base stations.

In addition to the above described terrestrial wireless network also non-terrestrial wireless communication networks exist including spaceborne transceivers, like satellites, and/or airborne transceivers, like unmanned aircraft systems. The non-terrestrial wireless communication network or system may operate in a similar way as the terrestrial system described above with reference to Fig. 1 , for example in accordance with the LTE-Advanced Pro standard or the 5G or NR, new radio, standard.

In mobile communication systems or networks, like those described above with reference to Fig. 1 , for example in a LTE or 5G/NR network, the respective entities may communicate using one of more frequency bands. A frequency band includes a start frequency, an end frequency and all intermediate frequencies between the start and end frequencies. In other words, the start, end and intermediate frequencies may define a certain bandwidth, e.g., 20MHz. A frequency band may also be referred to as a carrier, a bandwidth part, BWP, a subband, and the like.

When using a single frequency band, the communication may be referred to as a singleband operation, e.g., a UE transmits/receives radio signals to/from another network entity on frequencies being within the 20MHz band.

When using two or more frequency bands, the communication may be referred to as a multiband operation or as a wideband operation or as a carrier aggregation operation. The frequency bands may have different bandwidths or the same bandwidth, like 20MHz. For example, in case of frequency bands having the same bandwidths a UE may transmit/receive radio signals to/from another network entity on frequencies being within two or more of the 20MHz bands so that the frequency range for the radio communication may be a multiple of 20MHz. The two or more frequency bands may be continuous/adjacent frequency bands or some or all for the frequency bands may be separated in the frequency domain.

The multi-band operation may include frequency bands in the licensed spectrum, or frequency bands in the unlicensed spectrum, or frequency bands both in the licensed spectrum and in the unlicensed spectrum.

Carrier aggregation, CA, is an example using two or more frequency bands in the licensed spectrum and/or in the unlicensed spectrum.

5G New Radio (NR) may support an operation in the unlicensed spectrum so that a multiband operation may include frequency bands in the unlicensed spectrum bands. This may be as NR-based access to unlicensed spectrum, NR-U, and the frequency bands may be referred to as subbands. The unlicensed spectrum may include bands with a potential IEEE 802.11 coexistence, such as the 5GHz and the 6GHz bands. NR-U may support bandwidths that are an integer multiple of 20 MHz, for example due to regulatory requirements. The splitting into the subbands is performed so as to minimize interference with coexisting systems, like IEE 802.11 systems, which may operate in one or more of the same bands with the same nominal bandwidth channels, like 20 MHz channels. Other examples, of coexisting systems may use subbands having subband sizes and nominal frequencies different from the above-described IEEE 802.11 systems. For example, the unlicensed spectrum may include the 5GHz band, the 6GHz band, the 24GHz band or the 60GHz band or even higher frequency bands. Examples of such unlicensed bands include the industrial, scientific and medical, ISM, radio bands reserved internationally for the use of radio frequency energy for industrial, scientific and medical purposes other than telecommunications.

During an operation using unlicensed subbands regulations may define that a Listen-beforetalk, LBT, is to be performed separately per subband. This may lead to a situation in which one or more of the subbands are busy or occupied due to an interference, for example, from other communication systems coexisting on the same band, like other public land mobile networks, PLMNs or systems operating in accordance with the IEEE 802.11 specification. In such a situation, the transmitter, either the transmitting gNB or the transmitting UE, is only allowed to transmit on the subbands which are detected to be not busy, also referred to as subbands being free or non-occupied, as is determined by the LBT algorithm. For example for a transmission spanning more than 20MHz in the 5GHz operational unlicensed band, the transmitter, like the gNB or the UE, performs Listen-Before-Talk, LBT, separately on each subband. Once the LBT results are available for each subband, the devices, for example, the gNB in the downlink, DL, or the UE in the uplink, UL, are allowed to transmit on these subbands which are determined to be free or unoccupied, i.e., to transmit on the “won” subband(s). No transmission is allowed on the occupied, busy or “non-won” subbands.

It is noted that the information in the above section is only for enhancing the understanding of the background of the invention and therefore it may contain information that does not form prior art that is already known to a person of ordinary skill in the art.

In the 3GPP New Radio unlicensed (NR-U) and legacy standards, the transmission from a UE as well as a gNB is also dependent on the outcome of the listen before talk (LBT) procedure.

This procedure uses a random backoff to limit collisions during channel access. This randomness limits scheduler efficiency as the backoff time may not be known by other transmitters in the network.

Starting from a prior art as described above, there may be a need for improvements for the devices and for methods in a wireless communication system.

Moreover, a base station, gNB, for a wireless communication system according to an embodiment is provided. A backoff rule is stored within a storage of the base station and within a storage of a user device. Or, the base station is to receive the backoff rule from the user device. Or, the base station is to transmit the backoff rule to the user device. The user device is to determine a random backoff counter depending on the backoff rule and is to start a transmission of a data packet via a transmission channel depending on the backoff counter and depending on whether or not the transmission channel is occupied. Furthermore, a method for operating a wireless communication system according to an embodiment is provided. The method comprises:

Storing a backoff rule within a storage of a base station and within a storage of a user device; or transmitting the backoff rule from the user device to the base station; or receiving the backoff rule at the user device from the base station.

Determining, by the user device, a random backoff counter depending on the backoff rule.

Decrementing, by the user device, the random backoff counter if a transmission channel is not occupied for a certain duration.

- Transmitting, by the user device, a data packet via the transmission channel, if the random backoff counter reaches a predefined value.

Moreover, a method for operating a wireless communication system according to an embodiment is provided. The method comprises:

Storing a backoff rule within a storage of a base station and storing the backoff rule within a storage of a user device; or receiving the backoff rule from the user device at the base station; or transmitting the backoff rule from the base station to the user device.

The user device determines a random backoff counter depending on the backoff rule and starts a transmission of a data packet via a transmission channel depending on the backoff counter and depending on whether or not the transmission channel is occupied.

Furthermore, a computer program product comprising instructions which, when the program is executed by a computer, causes the computer to carry out one or more of the above- described methods is provided.

Embodiments of the present invention are now described in further detail with reference to the accompanying drawings:

Fig. 1 illustrates a schematic representation of an example of a wireless communication system. Fig. 2 illustrates a schematic representation of a wireless communication system including a transceiver, like a base station, and one or more transceivers, like user devices, UEs.

Fig. 3 illustrates an example of a computer system on which units or modules as well as the steps of the methods described in accordance with the inventive approach may execute.

Fig. 4 illustrates to user devices, UEs, having a random backoff timer and a base station according to an embodiment.

Embodiments of the present invention are now described in more detail with reference to the accompanying drawings in which the same or similar elements have the same reference signs assigned.

Embodiments of the present invention may be implemented in a wireless communication system as depicted in Fig. 1 including base stations and users, like mobile terminals or loT devices. Fig. 2 is a schematic representation of a wireless communication system including a transceivers 300, like a base station, and one or more other transceivers 302i to 302_n, like user devices, UEs. The base station 300 and the user devices 302 may communicate via one or more wireless communication links or channels 304a, 304b, 304c, like a radio link. The base station 300 may include one or more antennas ANTT or an antenna array having a plurality of antenna elements, a signal processor 300a and a transceiver unit 300b, coupled with each other. The user devices 302 include one or more antennas ANTR or an antenna array having a plurality of antennas, a signal processor 302ai, 302a_n, and a transceiver unit 302bi, 302b_n coupled with each other. The base station 300 and the UEs 302 may communicate via respective first wireless communication links 304a and 304b, like a radio link using the Uu interface, while the UEs 302 may communicate with each other via a second wireless communication link 304c, like a radio link using the PC5 interface. When the UEs 302 are not served by the base station 300, are not be connected to a base station, for example, they are not in an RRC connected state wrt. the network, or, more generally, when no resource allocation configuration or assistance is provided by the base station 300, the UEs 302 may communicate with each other over the sidelink directly. The system, the one or more UEs 302 and the base stations 300 may operate in accordance with the inventive teachings described herein. A user device, UE, for a wireless communication system according to an embodiment is provided. The user device may, e.g., be one of the user devices 302i, ... 302_n of Fig. 2, for example, user device 302i.

A backoff rule is stored within a storage of a base station 300 and within a storage of the user device. Or, the user device transmits the backoff rule to the base station 300. Or, the user device receives the backoff rule from the base station 300.

The user device 302i determines a random backoff counter depending on the backoff rule. (For example, the signal processor 302ai of the user device 302i may determine the random backoff counter.)

Moreover, the user device 302i decrements the random backoff counter if a transmission channel is not occupied for a certain duration.

Furthermore, the user device 302i transmits a data packet via the transmission channel (e.g., using its transceiver unit 302bi), if the random backoff counter reaches a predefined value.

Embodiments are based on the finding that it is useful that the base station is in possession of the backoff rule according to which the user device determines the random backoff counter. Being in possession of the backoff rule of the user device allows to enhance the capabilities of the base station. For example, the base station can (at least roughly) estimate the duration of the time period during which the user device defers a transmission in case of an occupied. Or, the base station can, for example, estimate an average delay of a planned transmission at the user devices, etc. On the other hand, with respect to the user device, it is necessary that the user device obeys the backoff rule which is known by the base station so that the base station can conduct proper estimations/determinations of backoff times.

According to an embodiment, the user device 302i does not change the random backoff counter while the transmission channel is occupied.

In an embodiment, the predefined value is zero.

According to an embodiment, the certain duration may depend on a transmission priority for transmitting the data packet. For example, the transmission priority may, e.g., be a priority value, e.g., an integer value between 1 and 4 (1; 2; 3; 4). Priority value 1 may indicate highest priority; priority value 4 may, e.g., indicate lowest priority. If a transmission has, e.g., priority value 4, the user device may, e.g., decrement the random backoff counter after determining that four listen-before- talk slots of the transmission channel have not been occupied. If a transmission has, e.g., priority value 3, the user device may, e.g., decrement the random backoff counter after determining that three listen-before-talk slots of the transmission channel have not been occupied. If a transmission has, e.g., priority value 2, the user device may, e.g., decrement the random backoff counter after determining that two listen-before-talk slots of the transmission channel have not been occupied. And, if a transmission has, e.g., priority value 1 , the user device may, e.g., decrement the random backoff counter after determining that one listen-before-talk slot of the transmission channel has not been occupied.

In some embodiments, the random backoff counter may, e.g., be determined pre-backoff. That means, when the user device 302 intends to transmit, the random backoff counter is determined, then backoff and sensing takes place, wherein the duration depends on the random backoff counter and the priority of the transmission, and then, the transmission is conducted by the user equipment.

In other embodiments, the random backoff counter may, e.g., be determined post-backoff. That means, after backoff, channel sensing and transmission has been conducted, the random backoff counter is immediately been determined, even without that the user device intends to immediately transmit a further data packet. Then the backoff counter is decremented, if the channel is determined to be free for a certain duration, up to reaching a another predefined value which is larger than the predefined value at which the user device would start transmitting. When later on, the user device 302 intends to transmit a further data packet, sensing takes place, wherein the duration depends on the remaining value of the already determined random backoff counter, and then, the transmission of the further packet is conducted by the user equipment.

According to an embodiment, the user device 302i may transmit the data packet via the transmission channel to the base station 300, if the random backoff counter reaches the predefined value.

In an embodiment, the backoff rule may comprise a pseudo random number generator algorithm. The pseudo random number generator algorithm is stored within the storage of the base station 300 and is stored within the storage of the user device 302i. Or, the user device 302i is may transmit the pseudo random number generator algorithm or an algorithm indication indicating the pseudo random number generator algorithm to the base station 300. Or, the user device 302i may receive the pseudo random number generator algorithm or the algorithm indication indicating the pseudo random number generator algorithm from the base station 300.

The pseudo random number algorithm may, e.g., be specified or may, e.g., be preconfigured.

According to an embodiment, the pseudo random number generator algorithm may e.g., be a Gold sequence generator algorithm. Or, the pseudo random number generator algorithm may e.g., be a Mersenne-Twister algorithm. Or, the pseudo random number generator algorithm may e.g., be a xorshift generator algorithm. Or, the pseudo random number generator algorithm may e.g., be a WELL generator algorithm.

In an embodiment, the backoff rule comprises a seed. The seed may e.g., be stored within the storage of the base station 300 and may e.g., be stored within the storage of the user device 302i. Or, the user device may transmit the seed to the base station 300. Or, the user device 302i may receive the seed from the base station 300.

In embodiments, at least parts of the seed may, e.g., need to be dynamic.

According to an embodiment, the user device 302i may e.g., be preconfigured with the pseudo random number generator algorithm and/or with seed information, wherein the seed depends on the seed information.

In general, different user devices within a wireless network may, e.g., have different seeds.

In an embodiment, the seed may depend on information that is available at the user device 302i and the base station 300, or on information that the user device 302i may transmit to the base station 300, or on information that the user device 302i may receive from the base station 300.

According to an embodiment, the seed may depend on one or more of: o a user identifier, user ID, and/or a user device specific radio network temporary identifier, RNTI, o a cell identifier, cell ID , o timing information, which, for example, depends on an OFDM symbol number and/or a slot number and/or a subframe number and/or a frame number, o the seed, wherein the user device 302i is to receive the seed from the base station 300, o the seed, wherein the seed is user-device-generated, and the user device 302i is to transmit the seed to the base station 300.

In an embodiment, the user device 302i may communicate over a sidelink or over a D2D interface, wherein, for example, the base station 300 is another user device. The other user device may, e.g., be a RSU road side unit or a Group leader UE (V2X), or a Master UE, or a iPhone® communication with watch, or a loT master (loT node with good connectivity).

Moreover, a base station 300, gNB, for a wireless communication system according to an embodiment is provided.

A backoff rule is stored within a storage of the base station 300 and within a storage of a user device 302i. Or, the base station 300 receives the backoff rule from the user device 302-1. Or, the base station 300 transmits (e.g., using its transceiver unit 300b) the backoff rule to the user device 302i. The user device 302i determines a random backoff counter depending on the backoff rule and is to start a transmission of a data packet via a transmission channel depending on the backoff counter and depending on whether or not the transmission channel is occupied.

According to an embodiment, the backoff rule may, e.g., comprise a pseudo random number generator algorithm. The pseudo random number generator algorithm is stored within the storage of the base station 300 and is stored within the storage of the user device 302i. Or, the base station 300 may receive the pseudo random number generator algorithm or an algorithm indication indicating the pseudo random number generator algorithm from the user device 302Ί. Or, the base station 300 may transmit the pseudo random number generator algorithm or the algorithm indication indicating the pseudo random number generator algorithm to the user device 302i.

In an embodiment, the pseudo random number generator algorithm may e.g., be a Gold sequence generator algorithm. Or, the pseudo random number generator algorithm may e.g., be a Mersenne-Twister algorithm. Or, the pseudo random number generator algorithm may e.g., be a xorshift generator algorithm. Or the pseudo random number generator algorithm may e.g., be a WELL generator algorithm.

According to an embodiment, the backoff rule comprises a seed. The seed may e.g., be stored within the storage of the base station 300 and may e.g., be stored within the storage of the user device 302i. Or, the base station 300 may receive the seed from the base station 300. Or, the base station 300 may transmit the seed to the user device 302i.

In an embodiment, the base station 300 may e.g., be preconfigured with the pseudo random number generator algorithm and/or with seed information, wherein the seed depends on the seed information.

According to an embodiment, the seed may e.g., depend on information that is available at the user device 302i and the base station 300, or on information that the base station 300 may transmit to the user device 302i, or on information that the base station 300 may receive from the user device 302i.

In an embodiment, the seed may e.g., depend on one or more of: o a user identifier, user ID, and/or a user device specific radio network temporary identifier, RNTI, o a cell identifier, cell ID , o timing information, which, for example, depends on an OFDM symbol number and/or a slot number and/or a subframe number and/or a frame number, o the seed, wherein the user device 302i is to receive the seed from the base station 300, o the seed, wherein the seed is user-device-generated, and the user device 302i is to transmit the seed to the base station 300.

According to an embodiment, the user device 302i is one of a plurality of user devices 302i_, ... 302_n, and the backoff rule is one of a plurality of backoff rules. For each user device of the plurality of user devices 302i, .. 302_n, one of the plurality of backoff rules is assigned to said user device. The plurality of backoff rules may e.g., be stored within a storage of a base station 300, and each backoff rule of the plurality of backoff rules may e.g., be stored within one of the plurality of user devices 302i_, .._. 302_n to which said backoff rule is assigned. Or, the base station 300 may receive the plurality of backoff rules from the plurality of user devices 302i_, 302_n. Or, for each of the plurality of backoff rules, the base station 300 may transmit said backoff rule to one of the plurality of user devices 302i, ._. 302_n to which said backoff rule is assigned.

In an embodiment, the base station 300 may conduct scheduling depending on the plurality of backoff rules. For example, scheduling may, e.g., be conducted by the signal processor 300a of the base station 300.

According to an embodiment, for a user device 302i of the plurality of user devices 302i,

... , 302_n, the base station 300 may estimate, depending on the backoff rule being assigned to the user device 302i, a time period during which the user device 302i is not expected to transmit via the transmission channel, and the base station does not monitor whether or not the user device 302i transmits via the transmission channel during the time period. For example, the base station 300 may, e.g., determine the backoff counter value depending on the backoff rule and may estimate the time period during which it does not expect the user device 302i to transmit via the transmission channel from the determined backoff counter value.)

(E.g., before at least the time corresponding to the backoff counter value that has been drawn from the random number generator.)

In an embodiment, the base station 300 may determine a channel business at the user device depending on the plurality of backoff rules.

According to an embodiment, the base station 300 may determine the channel business by determining a channel business ratio CBR according to

CBR = (NJx - N_bo) / N_tx,

N_tx is a number of Listen-before-talk, LBT, slots from the beginning of a grant till an actual transmission. N_bo is the number of Listen-before-talk slots which was drawn by a pseudo random number generator as backoff. Furthermore, a wireless communication system according to an embodiment is provided. The wireless communication system comprises one or more user devices, 302i, ..., 302_n as described above and a base station 300 as described above.

In the following, embodiments of the present invention are described in more detail.

In embodiments, to overcome the issue of not knowing the backoff time while still fulfilling the required random backoff a pseudo random number generator (PRNG) with a seed which is known/derivable for both parties, is proposed. This way any transceiver in the network can calculate the current backoff timer of any other UE, if it knows the seed being used.

The seed can either be signaled or derived from known user specific as well as global properties.

Embodiment-1 : The PRNG algorithm as well as the information used to calculate the seed is preconfigured or configured to the UE.

For example, The PRNG algorithm may be a Gold sequence generator, such as in 36.211 or 38.211, Mersenne-Twister, xorshift generators, WELL generators, or any other pseudo random number generator which is used for calculating the random backoff value.

The seed is also calculated based on a pre-configured or configured formula which includes information which is available to both sides, such as:

• User ID, UE-specific RNTI

• Cell ID

^• Timing information, e.g. slot, subframe, frame number

In this way the gNB can calculate the current minimum random backoff values of all UEs in the network making better scheduling decisions, since it knows the earliest point in time when the UE will start.

Furthermore, the gNB does not have to monitor the channel for the transmission of that specific UE which saves power at the gNB side. In a further embodiment, we propose to exploit the information on the difference of the calculated random backoff and the actual transmission time to derive information on the channel occupation at the UE side. Since the delay compared to the calculated random backoff is caused by a busy channel at the UE, the gNB implicitly knows the channel busy ratio (CBR) by the following relation:

CBR = (N_tx - N_bo) / N_tx, where N_tx is the number of LBT slots from the beginning of the grant till the actual transmission and N_bo is the number of LBT slots which was drawn by the PRNG as backoff.

For example, by scheduling 2 UEs that have a random backoff timer of 6 and 7 leads to minimal pauses between uplink transmissions as shown in Fig. 4.

Alternatively, the RNG (random number generator) can be configured by the network during connection setup.

This can for example be done using RRC (radio resource control) signaling to initialize the RNG with a given seed.

Embodiments of the present invention have been described in detail above, and the respective embodiments and aspects may be implemented individually or two or more of the embodiments or aspects may be implemented in combination.

With regard to the above-described embodiments of the various aspects of the present invention, it is noted that they have been described in an environment in which a communication is between a transmitter, like a gNB or a UE, and a receiver, like a UE and a gNB. However, the invention is not limited to such a communication, rather, the above- described principles may equally be applied for a device-to-device communication, like a D2D, V2V, V2X communication. In such scenarios, the communication is over a sidelink between the respective devices. The transmitter is a first UE and the receiver is a second UE communicating using the sidelink resources. In accordance with embodiments, the wireless communication system may include a terrestrial network, or a non-terrestrial network, or networks or segments of networks using as a receiver an airborne vehicle or a spaceborne vehicle, or a combination thereof.

In accordance with embodiments, a UE may comprise one or more of a mobile or stationary terminal, an loT device, a ground-based vehicle, an aerial vehicle, a drone, a building, or any other item or device provided with network connectivity enabling the item/device to communicate using the wireless communication system, like a sensor or actuator, or a Wifi non-AP STA (AP = Access Point; STA = Station, user device in IEEE 802.11), e.g. 802.11 ax or 802.11be. In accordance with embodiments, a base station may comprise one or more of a macro cell base station, or a small cell base station, or a spaceborne vehicle, like a satellite or a space, or an airborne vehicle, like a unmanned aircraft system (UAS), e.g., a tethered UAS, a lighter than air UAS (LTA), a heavier than air UAS (HTA) and a high altitude UAS platforms (HAPs), or any transmission/reception point (TRP) enabling an item or a device provided with network connectivity to communicate using the wireless communication system, or a Wifi AP STA, e.g. 802.11 ax or 802.11 be.

Although some aspects of the described concept have been described in the context of an apparatus, it is clear that these aspects also represent a description of the corresponding method, where a block or a device corresponds to a method step or a feature of a method step. Analogously, aspects described in the context of a method step also represent a description of a corresponding block or item or feature of a corresponding apparatus.

Various elements and features of the present invention may be implemented in hardware using analog and/or digital circuits, in software, through the execution of instructions by one or more general purpose or special-purpose processors, or as a combination of hardware and software. For example, embodiments of the present invention may be implemented in the environment of a computer system or another processing system.

Fig. 3 illustrates an example of a computer system 500. The units or modules as well as the steps of the methods performed by these units may execute on one or more computer systems 500. The computer system 500 includes one or more processors 502, like a special purpose or a general-purpose digital signal processor. The processor 502 is connected to a communication infrastructure 504, like a bus or a network. The computer system 500 includes a main memory 506, e.g., a random-access memory (RAM), and a secondary memory 508, e.g., a hard disk drive and/or a removable storage drive. The secondary memory 508 may allow computer programs or other instructions to be loaded into the computer system 500. The computer system 500 may further include a communications interface 510 to allow software and data to be transferred between computer system 500 and external devices. The communication may be in the from electronic, electromagnetic, optical, or other signals capable of being handled by a communications interface. The communication may use a wire or a cable, fiber optics, a phone line, a cellular phone link, an RF link and other communications channels 512.

The terms “computer program medium” and “computer readable medium” are used to generally refer to tangible storage media such as removable storage units or a hard disk installed in a hard disk drive. These computer program products are means for providing software to the computer system 500. The computer programs, also referred to as computer control logic, are stored in main memory 506 and/or secondary memory 508. Computer programs may also be received via the communications interface 510. The computer program, when executed, enables the computer system 500 to implement the present invention. In particular, the computer program, when executed, enables processor 502 to implement the processes of the present invention, such as any of the methods described herein. Accordingly, such a computer program may represent a controller of the computer system 500. Where the disclosure is implemented using software, the software may be stored in a computer program product and loaded into computer system 500 using a removable storage drive, an interface, like communications interface 510.

The implementation in hardware or in software may be performed using a digital storage medium, for example cloud storage, a floppy disk, a DVD, a Blue-Ray, a CD, a ROM, a PROM, an EPROM, an EEPROM or a FLASH memory, having electronically readable control signals stored thereon, which cooperate (or are capable of cooperating) with a programmable computer system such that the respective method is performed. Therefore, the digital storage medium may be computer readable.

Some embodiments according to the invention comprise a data carrier having electronically readable control signals, which are capable of cooperating with a programmable computer system, such that one of the methods described herein is performed.

Generally, embodiments of the present invention may be implemented as a computer program product with a program code, the program code being operative for performing one of the methods when the computer program product runs on a computer. The program code may for example be stored on a machine readable carrier.

Other embodiments comprise the computer program for performing one of the methods described herein, stored on a machine readable carrier. In other words, an embodiment of the inventive method is, therefore, a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer.

A further embodiment of the inventive methods is, therefore, a data carrier (or a digital storage medium, or a computer-readable medium) comprising, recorded thereon, the computer program for performing one of the methods described herein. A further embodiment of the inventive method is, therefore, a data stream or a sequence of signals representing the computer program for performing one of the methods described herein. The data stream or the sequence of signals may for example be configured to be transferred via a data communication connection, for example via the Internet. A further embodiment comprises a processing means, for example a computer, or a programmable logic device, configured to or adapted to perform one of the methods described herein. A further embodiment comprises a computer having installed thereon the computer program for performing one of the methods described herein.

In some embodiments, a programmable logic device (for example a field programmable gate array) may be used to perform some or all of the functionalities of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor in order to perform one of the methods described herein. Generally, the methods are preferably performed by any hardware apparatus.

The above described embodiments are merely illustrative for the principles of the present invention. It is understood that modifications and variations of the arrangements and the details described herein are apparent to others skilled in the art. It is the intent, therefore, to be limited only by the scope of the impending patent claims and not by the specific details presented by way of description and explanation of the embodiments herein.

List of Acronyms and Symbols:

RNG Random Number Generator

PRNG Pseudo Random Number Generator eNB Evolved Node B (3G base station)

LTE Long-Term Evolution

UE User Equipment (User Terminal)

RSU Road Side Unit

Uu eNB-UE link

PC5 UE-UE link / Interface using Sidelink Channel for D2D communication

D2D Device-to-device

IE Information Element

V2V Vehicular-to-vehicular communications

V2X Vehicular-to-everything communications

HARQ Hybrid Automatic Repeat Request

NR-U New Radio in unlicensed spectrum

BS Base Station gNB Generation Node B (base station)

RAN Radio Access Network

FDM Frequency Division Multiplexing

RA Resource Allocation

SCI Sidelink Control Information

SL Sidelink sTTI Short(end) Transmission Time Interval

PUCCH Physical Uplink Control Channel

PDCCH Physical Downlink Control Channel

DMRS Demodulation Reference Signal

CBR Channel Busy Ratio

COT Channel occupancy time

CWS Contention Window Size

RtoTx Ready to Transmit

RtoRx Ready to Receive

LBT Listen-before-T alk

LBR Listen-before-Receive

Claims

Claims:

1. A user device, UE, for a wireless communication system, wherein a backoff rule is stored within a storage of a base station and within a storage of the user device; or the user device is to transmit the backoff rule to the base station; or the user device is to receive the backoff rule from the base station, wherein, the user device is to determine a random backoff counter depending on the backoff rule, wherein the user device is to decrement the random backoff counter if a transmission channel is not occupied for a certain duration, wherein the user device is to transmit a data packet via the transmission channel, if the random backoff counter reaches a predefined value.

2. The user device according to claim 1, wherein the user device is to not change the random backoff counter while the transmission channel is occupied.

3. The user device according to claim 1 or 2, wherein the predefined value is zero.

4. The user device according to one of the preceding claims, wherein the certain duration depends on a transmission priority for transmitting the data packet.

5. The user device according to one of the preceding claims, wherein the user device is to transmit the data packet via the transmission channel to the base station, if the random backoff counter reaches the predefined value.

6. The user device according to one of the preceding claims, wherein the backoff rule comprises a pseudo random number generator algorithm, wherein the pseudo random number generator algorithm is stored within the storage of the base station and is stored within the storage of the user device; or the user device is to transmit the pseudo random number generator algorithm or an algorithm indication indicating the pseudo random number generator algorithm to the base station; or the user device is to receive the pseudo random number generator algorithm or the algorithm indication indicating the pseudo random number generator algorithm from the base station.

7. The user device according to claim 6, wherein the pseudo random number generator algorithm is a Gold sequence generator algorithm, or wherein the pseudo random number generator algorithm is a Mersenne-Twister algorithm, or wherein the pseudo random number generator algorithm is a xorshift generator algorithm, or wherein the pseudo random number generator algorithm is a WELL generator algorithm.

8. The user device according to claim 6 or 7, wherein the backoff rule comprises a seed, wherein the seed is stored within the storage of the base station and is stored within the storage of the user device; or the user device is to transmit the seed to the base station; or the user device is to receive the seed from the base station.

9. The user device according to claim 8, wherein the user device is preconfigured with the pseudo random number generator algorithm and/or with seed information, wherein the seed depends on the seed information.

10. The user device according to claim 8 or 9, wherein the seed depends on information that is available at the user device and the base station, or on information that the user device is to transmit to the base station, or on information that the user device is to receive from the base station.

11. The user device according to one of claims 8 to 10, wherein the seed depends on one or more of: o a user identifier, user ID, and/or a user device specific radio network temporary identifier, RNTI, o a cell identifier, cell ID , o timing information, which, for example, depends on an OFDM symbol number and/or a slot number and/or a subframe number and/or a frame number, o the seed, wherein the user device is to receive the seed from the base station, o the seed, wherein the seed is user-device-generated, and the user device is to transmit the seed to the base station.

12. The user device according to one of the preceding claims, wherein the user device is to communicate over a sidelink or over a D2D interface, wherein, for example, the base station is another user device.

13. A base station, gNB, for a wireless communication system, wherein a backoff rule is stored within a storage of the base station and within a storage of a user device; or the base station is to receive the backoff rule from the user device; or the base station is to transmit the backoff rule to the user device, wherein, the user device is to determine a random backoff counter depending on the backoff rule and is to start a transmission of a data packet via a transmission channel depending on the backoff counter and depending on whether or not the transmission channel is occupied.

14. The base station according to claim 13, wherein the backoff rule comprises a pseudo random number generator algorithm, wherein the pseudo random number generator algorithm is stored within the storage of the base station and is stored within the storage of the user device; or the base station is to receive the pseudo random number generator algorithm or an algorithm indication indicating the pseudo random number generator algorithm from the user device; or the base station is to transmit the pseudo random number generator algorithm or the algorithm indication indicating the pseudo random number generator algorithm to the user device.

15. The base station according to claim 14, wherein the pseudo random number generator algorithm is a Gold sequence generator algorithm, or wherein the pseudo random number generator algorithm is a Mersenne-Twister algorithm, or wherein the pseudo random number generator algorithm is a xorshift generator algorithm, or wherein the pseudo random number generator algorithm is a WELL generator algorithm.

16. The base station according to claim 14 or 15, wherein the backoff rule comprises a seed, wherein the seed is stored within the storage of the base station and is stored within the storage of the user device; or the base station is to receive the seed from the base station; or the base station is to transmit the seed to the user device.

17. The base station according to claim 16, wherein the base station is preconfigured with the pseudo random number generator algorithm and/or with seed information, wherein the seed depends on the seed information.

18. The base station according to claim 16 or 17 wherein the seed depends on information that is available at the user device and the base station, or on information that the base station is to transmit to the user device, or on information that the base station is to receive from the user device.

19. The base station according to one of claims 16 to 18, wherein the seed depends on one or more of: o a user identifier, user ID, and/or a user device specific radio network temporary identifier, RNTI, o a cell identifier, cell ID , o timing information, which, for example, depends on an OFDM symbol number and/or a slot number and/or a subframe number and/or a frame number, o the seed, wherein the user device is to receive the seed from the base station, o the seed, wherein the seed is user-device-generated, and the user device is to transmit the seed to the base station.

20. The base station according to one of claims 13 to 19, wherein the user device is one of a plurality of user devices, wherein the backoff rule is one of a plurality of backoff rules, wherein for each user device of the plurality of user devices, one of the plurality of backoff rules is assigned to said user device, wherein the plurality of backoff rules is stored within a storage of a base station, and each backoff rule of the plurality of backoff rules is stored within one of the plurality of user devices to which said backoff rule is assigned; or the base station is to receive the plurality of backoff rules from the plurality of user devices; or wherein for each of the plurality of backoff rules, the base station is to transmit said backoff rule to one of the plurality of user devices to which said backoff rule is assigned.

21. The base station according to claim 20, wherein the base station is to conduct scheduling depending on the plurality of backoff rules.

22. The base station according to claim 20 or 21, wherein, for a user device of the plurality of user devices, the base station is to estimate, depending on the backoff rule being assigned to the user device, a time period during which the user device is not expected to transmit via the transmission channel, and wherein the base station is to not monitor whether or not the user device transmits via the transmission channel during the time period.

23. The base station according to one of claims 20 to 22, wherein the base station is to determine a channel business at the user device depending on the plurality of backoff rules.

24. The base station according to claim 23, wherein the base station is to determine the channel business by determining a channel business ratio CBR according to

CBR = (N Jx - N_bo) / N x, wherein NJx is a number of Listen-before-talk, LBT, slots from the beginning of a grant till an actual transmission, and wherein N_bo is the number of Listen-before-talk slots which was drawn by a pseudo random number generator as backoff.

25. A wireless communication system, comprising: one or more user devices, wherein each of the one or more user devices is a user device according to one of claims 1 to 12, and a base station according to one of claims 13 to 24.

26. A method for operating a wireless communication system, wherein the method comprises:

Storing a backoff rule within a storage of a base station and within a storage of a user device; or transmitting the backoff rule from the user device to the base station; or receiving the backoff rule at the user device from the base station, determining, by the user device, a random backoff counter depending on the backoff rule, decrementing, by the user device, the random backoff counter if a transmission channel is not occupied for a certain duration, transmitting, by the user device, a data packet via the transmission channel, if the random backoff counter reaches a predefined value.

27. A method for operating a wireless communication system, wherein the method comprises:

Storing a backoff rule within a storage of a base station and storing the backoff rule within a storage of a user device; or receiving the backoff rule from the user device at the base station; or transmitting the backoff rule from the base station to the user device, wherein, the user device determines a random backoff counter depending on the backoff rule and starts a transmission of a data packet via a transmission channel depending on the backoff counter and depending on whether or not the transmission channel is occupied.

28. A computer program product comprising instructions which, when the program is executed by a computer, causes the computer to carry out one or more methods in accordance with claim 26 or 27.