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WO2023033688A1 - Procédés et appareils de détermination de paramètres de transmission - Google Patents

Procédés et appareils de détermination de paramètres de transmission Download PDF

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Publication number
WO2023033688A1
WO2023033688A1 PCT/SE2021/050846 SE2021050846W WO2023033688A1 WO 2023033688 A1 WO2023033688 A1 WO 2023033688A1 SE 2021050846 W SE2021050846 W SE 2021050846W WO 2023033688 A1 WO2023033688 A1 WO 2023033688A1
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WIPO (PCT)
Prior art keywords
wireless device
base station
correction
bandwidth
transmissions
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/SE2021/050846
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English (en)
Inventor
Petter ERSBO
Karl Werner
David Astely
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Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
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Priority to PCT/SE2021/050846 priority Critical patent/WO2023033688A1/fr
Publication of WO2023033688A1 publication Critical patent/WO2023033688A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/04—Wireless resource allocation
    • H04W72/044—Wireless resource allocation based on the type of the allocated resource
    • H04W72/0457—Variable allocation of band or rate
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B17/00—Monitoring; Testing
    • H04B17/30—Monitoring; Testing of propagation channels
    • H04B17/309—Measuring or estimating channel quality parameters
    • H04B17/336—Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0002—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate
    • H04L1/0003—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate by switching between different modulation schemes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0009—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the channel coding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0015—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/20—Arrangements for detecting or preventing errors in the information received using signal quality detector
    • H04L1/203—Details of error rate determination, e.g. BER, FER or WER
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/16—Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]
    • H04W28/18—Negotiating wireless communication parameters
    • H04W28/20—Negotiating bandwidth
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/50—Allocation or scheduling criteria for wireless resources
    • H04W72/54—Allocation or scheduling criteria for wireless resources based on quality criteria
    • H04W72/542—Allocation or scheduling criteria for wireless resources based on quality criteria using measured or perceived quality

Definitions

  • Embodiments of the present disclosure relate to wireless communications networks and, in particular, to methods and apparatus for determining one or more transmission parameters for transmissions from a wireless device to a base station in a wireless communications network.
  • transmissions may be scheduled by assigning radio-frequency resources for a device to use when transmitting. Scheduling may take into account how much data is to be sent or received, as well as channel and interference conditions. Transport blocks may be scheduled for transmission on a per-slot basis, in which a slot has a duration of one millisecond or less. Scheduling can also involve link adaptation, in which one or more transmission parameters are set.
  • the transmission parameters may include, for example, rank (e.g. a number of spatially multiplexed layers), a modulation scheme, a channel code rate and transmit power.
  • the transmit power per resource block is typically kept constant, whilst the number of resource blocks assigned to a device can vary. This means that the total transmit power typically depends on the total number of allocated resource elements.
  • the total transmit power is often lower and the situation can be more complicated.
  • the transmit power per resource block typically depends on the number of resource blocks used for transmission.
  • UEs closer to the base station may not need to transmit at their maximum transmit power. Instead, the transmit power of these UEs can be controlled so that the received power per resource block at the base station is at a desirable level.
  • the total transmit power scales linearly with the number of resource blocks up to a certain limit, beyond which the transmit power per resource block depends on the number of resource blocks.
  • the total transmit power may scale linearly with the number of resource blocks whilst the total transmit power is below a maximum power limit. Once the maximum power limit is reached, the transmit power per resource block decreases as increasing numbers of resource blocks are used.
  • the transmit power per resource block can depend on the number of resource blocks used, and the number of resource blocks used depends on bandwidth, the probability of a transmission being successfully received can be improved by determining the transmission bandwidth based on channel conditions.
  • channel conditions may be used to determine not only rank, modulation order and channel code rate (e.g. a modulation and coding scheme, MCS), but also the bandwidth.
  • Bandwidth selection can be particularly important for cell edge terminals which transmit with their maximum allowed transmit power.
  • the process of determining of rank, MCS and/or bandwidth can be referred to as link adaptation.
  • the transmit power per resource block is P/M. Since the signal-to-noise ratio (SNR) is proportional to the transmit power, if the data rate was proportional to the SNR, then the number of resource blocks M could be chosen in order to reach the desired data rate. However, in practice, data rates tend to be proportional to the logarithm of the SNR, which suggests that the largest bandwidth possible should be used.
  • SNR signal-to-noise ratio
  • the bandwidth should be neither too high (relative to the lowest code rate), nor too low (relative to the diminishing “logarithmic” returns from increasing SNR).
  • One way to select rank, MCS and/or bandwidth is to compare the expected throughput for different combinations of these parameters for the estimated channel.
  • the combinations to be compared may be subject to a constraint on an expected error rate (e.g. the block error rate, BLER), which indicates how likely it is that a transmission will fail.
  • BLER block error rate
  • a target BLER of 0.1 for initial transmissions is commonly used for mobile broadband applications.
  • OLLA outer loop link adaptation
  • SNR estimate a channel quality estimate
  • An integrating controller can be used to implement OLLA, for example. This approach can be used to achieve an error rate that is comparable to, or better than the target BLER. Further information regarding OLLA can be found in “Selection of MOS levels in HSDPA”, 3GPP TSG RAN WG1 Technical document, R1-01-0589, May 2001.
  • the present disclosure provides an apparatus for determining one or more transmission parameters for transmissions from a wireless device to a base station in a wireless communications network.
  • the apparatus comprises a processor and a machine- readable medium, in which the machine-readable medium contains instructions which, when executed by the processor, cause the apparatus to obtain a channel quality estimate based on one or more signals transmitted between the base station and the wireless device, and apply a correction to the channel quality estimate to obtain an adjusted channel quality estimate.
  • the correction is determined based on a transmission bandwidth of the wireless device and a decoding result for one or more first transmissions received by the base station.
  • the apparatus is further caused to determine one or more transmission parameters for the transmission bandwidth based on the adjusted channel quality estimate and configure the wireless device to perform one or more second transmissions with the transmission bandwidth according to the one or more transmission parameters.
  • a method for determining one or more transmission parameters for transmissions from a wireless device to a base station in a wireless communications network comprises obtaining a channel quality estimate based on one or more signals transmitted between the base station and the wireless device and applying a correction to the channel quality estimate to obtain an adjusted channel quality estimate.
  • the correction is determined based on a transmission bandwidth of the wireless device and a decoding result for one or more first transmissions received by the base station.
  • the method further comprises determining one or more transmission parameters for the transmission bandwidth based on the adjusted channel quality estimate and configuring the wireless device to perform one or more second transmissions with the transmission bandwidth according to the one or more transmission parameters.
  • an apparatus configured to perform the aforementioned method is provided.
  • a computer program comprises instructions which, when executed on at least one processor of an apparatus, cause the apparatus to carry out the aforementioned method.
  • a carrier containing the computer program is provided, in which the carrier is one of an electronic signal, optical signal, radio signal, or non-transitory machine-readable storage medium.
  • a computer program product is provided. The computer program product comprises non transitory computer readable media having the computer program stored thereon.
  • Figure 1 shows an illustration of a wireless communications network according to aspects of the disclosure
  • Figure 2 shows the change in throughput for signal-to-noise values in a simulation of transmissions from a wireless device to a base station
  • Figure 3 shows an example of an apparatus according to aspects of the disclosure
  • Figure 4 shows the change in throughput for signal-to-noise values in a simulation of transmissions from a wireless device to a base station according to aspects of the disclosure
  • Figure 5 shows a flowchart of a method according to aspects of the disclosure
  • Figure 6 shows a signalling diagram according to aspects of the disclosure.
  • Figure 7 show an example of an apparatus according to aspects of the disclosure. Detailed description
  • FIG. 1 shows a wireless communications network 100 according to embodiments of the disclosure.
  • the wireless communications network 100 may implement any suitable wireless communications protocol or technology, such as Global System for Mobile communication (GSM), Wide Code-Division Multiple Access (WCDMA), Long Term Evolution (LTE), New Radio (NR), WiFi, WiMAX, or Bluetooth wireless technologies.
  • GSM Global System for Mobile communication
  • WCDMA Wide Code-Division Multiple Access
  • LTE Long Term Evolution
  • NR New Radio
  • WiFi WiMAX
  • Bluetooth wireless technologies such as Bluetooth wireless technology.
  • the wireless communications network 100 forms part of a cellular telecommunications network, such as the type developed by the 3 rd Generation Partnership Project (3GPP).
  • 3GPP 3 rd Generation Partnership Project
  • the wireless communications network 100 comprises a base station 102 which is operable to connect a user equipment (UE) 104 to a core network 106 via a backhaul network 108.
  • the base station 102 may thus act as a radio access node, connecting the UE 104 to the rest of the communications network 100.
  • the base station 102 may be any suitable base station such as, for example, a Node B, an evolved Node B (eNB), or an NR NodeB (gNB).
  • Figure 1 shows the base station 102 as one integral unit, the skilled person will appreciate that in general the base station 102 may comprise one or more units which may be distributed over one or more sites.
  • the UE 104 may be any suitable wireless device which is connectable to the wireless communications network 100 by a radio access node such as the base station 102.
  • the UE 104 may be, for example, a wireless terminal device or a mobile device.
  • the UE 104 may support any suitable form of communication such as, for example, device-to-device (D2D) communication, machine-to-machine (M2M) communication and/or communications according to the 3GPP narrow band internet of things (NB-loT) standard.
  • D2D device-to-device
  • M2M machine-to-machine
  • NB-loT 3GPP narrow band internet of things
  • Link adaptation can be used to adaptively adjust transmission parameters, such as rank, the modulation and coding scheme (MCS) and/or bandwidth, based on channel conditions.
  • MCS modulation and coding scheme
  • the effectiveness of link adaptation techniques depends on the accuracy of channel quality estimates. Inaccuracies in channel quality estimates can be mitigated by adjusting channel quality estimates based on historic decoding performance for signals received at the base station 102 from the UE 104, in a process which may be referred to as outer loop link adaptation.
  • this can still result in sub-optimal bandwidths being selected. For example, higher bandwidths may be preferentially selected, even when a lower (smaller) bandwidth would give a higher throughput.
  • Figure 2 shows the throughput for simulations of transmissions from a UE to a base station, in which the base station comprises 64 receiving antennas.
  • the dashed lines show the throughput that would be achieved for various bandwidths that are quantified in terms of a number of physical resource blocks (PRBs).
  • the solid black lines shows the throughput that is achieved using an existing outer link loop adaptation technique, in which the transmission parameters is selected based on an adjusted signal-to-noise ratio (SNR) estimate.
  • SNR signal-to-noise ratio
  • Embodiments of the disclosure seek to address these and other problems by providing an apparatus for determining one or more transmission parameters for transmissions from a wireless device to a base station in a wireless communication network (e.g. for uplink transmissions).
  • the apparatus adjusts a channel quality estimate for a channel between the base station and the wireless device based on a bandwidth of the wireless device and the decoding performance for transmissions received by the base station.
  • the apparatus determines one or more transmission parameters for the transmission bandwidth based on the adjusted channel quality estimate and configures the wireless device to perform transmissions with the transmission bandwidth according to the determined one or more transmission parameters.
  • the present disclosure thus provides a link adaptation method in which channel quality estimates are adjusted based on the bandwidth with which the wireless device is to transmit. Applying a bandwidth-specific adjustment to the channel quality estimate accounts for bandwidth-dependent channel estimation error, in which the increased power per resource block with a lower bandwidth may lead to a smaller estimation error.
  • the present disclosure provides a more accurate channel quality estimate for determining transmission parameters, which leads to improvements in uplink throughput.
  • the base station 102 may obtain a channel quality estimate for one or more signals sent between the UE 104 and the base station 102.
  • the channel quality estimate may comprise, for example, a signal-to- interference-and-noise (SI NR) or SNR estimate.
  • SI NR signal-to- interference-and-noise
  • a correction for the channel quality estimate is determined based on a transmission bandwidth of the UE 104 and a decoding result for one or more first transmissions received by the base station 102.
  • the correction may be a bandwidth-specific correction.
  • the one or more first transmissions may be received by the base station 102 at the transmission bandwidth such that the correction is determined based on decoding result(s) for transmissions made at that transmission bandwidth only.
  • the base station 102 applies the correction to the channel quality estimate to determine an adjusted channel quality estimate.
  • the base station 102 determines one or more transmission parameters for the UE 104 using the adjusted channel quality estimate.
  • the base station 102 may thus, for example, determine one or more of: a modulation and coding scheme (MCS), bandwidth and rank for the UE 104 based on the adjusted channel quality estimate.
  • MCS modulation and coding scheme
  • the base station 102 configures the UE 104 to transmit using the one or more transmission parameters. For example, the base station 102 may determine an uplink grant scheduling one or more second transmissions to be performed by the UE 104 and send the uplink grant to the UE 104. In another example, the base station 102 may send the one or more transmission parameters to the UE 104. The UE 104 may transmit according to the transmission parameters received from the base station 102 (e.g. in one or more autonomous transmissions).
  • the base station 102 is described as determining the transmission parameters for the UE 104, the skilled person will appreciate that the present disclosure is not limited as such.
  • the transmission parameters may be determined by another node in the network 100, such as a node in the core network 106, for example.
  • the actions described as being performed by the base station 102 may be performed by any suitable apparatus.
  • the process of determining and applying the correction to the channel quality estimate is described in more detail in respect of Figure 3, which shows an example of an apparatus 300 in a wireless communication network according to embodiments of the disclosure.
  • the wireless communication network may be the wireless communication network 100 described above in respect of Figure 1 , for example.
  • the apparatus 300 is operable to store a plurality of corrections (or adjustments), in which each correction is specific to a respective bandwidth and a respective UE in a plurality of UEs.
  • the apparatus 300 may thus be operable to store M corrections, in which each correction corresponds to a respective bandwidth of M bandwidths.
  • the apparatus may store corrections for different bandwidths (and/or different numbers of bandwidths) for different UEs.
  • the correction for a particular UE and a particular bandwidth is determined by setting the correction to an initial value and updating the correction based on one or more decoding results for transmissions sent by the UE to the base station with the bandwidth.
  • the UE may be the UE 104 described above in respect of Figure 1 , for example.
  • the base station may be the base station 102 described above in respect of Figure 1 , for example.
  • the initial value may be any suitable value.
  • the initial value may be a non-zero value.
  • the same initial value may be used for all UEs and/or bandwidths.
  • the initial value may be specific to a UE and/or bandwidth.
  • the apparatus 300 is operable to receive decoding performance information 302 for transmissions sent by the UE 104 to the base station 102.
  • the decoding performance information 302 comprises a UE identifier which identifies the UE 104, a decoding result for a transmission sent by the UE 104 to the base station 102 and an indication of the bandwidth of the transmission.
  • the decoding performance information 302 may thus, for example, comprise the bandwidth itself or an indicator which identifies the bandwidth.
  • the decoding result indicates whether or not the transmission was successfully decoded by the base station 102.
  • an error detecting code may be included in the transmission, in which the error detecting code is based on the other contents (e.g. data) of the transmission.
  • the base station 102 can compare the error detecting code to the decoded data to determine whether or not there is a match (e.g. whether or not they are consistent). If there is no match, then decoding is deemed to have failed and the decoding result may thus indicate that a failure has occurred. If there is a match, then decoding is deemed to have succeeded and the decoding result may thus indicate that a success has occurred.
  • Any suitable error detecting code may be used, such as for example, a cyclic redundancy check (CRC) code.
  • the apparatus 300 is operable to update the correction for the UE 104 and the bandwidth identified in the decoding performance information 302 based on the decoding result included in the decoding performance information 302. For example, the apparatus 300 may be operable to increase the correction when the decoding result indicates that a decoding attempt failed and decrease the correction when the decoding result indicates that a decoding attempt succeeded.
  • the apparatus 300 may increase the correction by adding a first value to the correction.
  • the apparatus 300 may decrease the correction by subtracting a second value from the correction.
  • the apparatus 300 may, equivalently, increase the correction by subtracting a first value from the correction if the first value is negative.
  • the apparatus 300 may decrease the correction by adding the second value to the correction if the second value is negative.
  • the first and second value may be related to one another.
  • the first value, A CK may be related to the second value, L NACK by:
  • ACK BLER X N A CK> in which BLER is a target Block Error Rate.
  • the apparatus 300 may update the correction one or more times as new decoding performance information 302 for the UE and bandwidth are received. In this way, the apparatus 300 can iteratively adapt the correction for a particular UE and bandwidth based on decoding results for that UE and bandwidth. This allows for adjusting the correction for the SI NR estimate over time, thereby accounting for changes in channel conditions which may affect channel estimation accuracy. Determining a bandwidthspecific adjustment for the channel quality estimate enables accounting for bandwidthdependent channel estimation error, which can lead to more accurate channel quality estimates.
  • the apparatus 300 is thus operable to determine bandwidth-specific channel quality estimate corrections for UEs based on decoding results for transmissions sent by the UEs at the bandwidths. In the aforementioned description, the apparatus 300 is operable to update the correction for a UE and bandwidth when decoding results for that UE and bandwidth are received.
  • the apparatus 300 may be operable to update the correction for the UE and any bandwidths that are similar to the bandwidth of the transmissions for which the decoding results were received.
  • the apparatus 300 may update the corrections for any other bandwidths that differ from the first bandwidth by less than a predetermined threshold. This means that more corrections are updated each time decoding results are received, which can cause the corrections converge more quickly.
  • the difference between the first bandwidth and the other bandwidth is small, the corrections for the first bandwidth and other bandwidths may be expected to be similar.
  • the apparatus 300 may be operable to update the correction for the UE and all bandwidths that are equal to or higher (larger) than the bandwidth of the transmissions for which the decoding results were received. This can make the corrections converge more quickly and reduce the error rate after retransmission.
  • one correction may be used for multiple UEs.
  • the apparatus 300 may, for example, group UEs into one or more groups according to one or more criteria and use a same correction for all UEs in a group.
  • the apparatus 300 may thus update the correction for a group of UEs when decoding results for any of the UEs in that group are received.
  • the UEs may be grouped according to any suitable criteria such as, for example, one or more criteria relating to: a property of a channel between the base station and the respective UE; a capability of the respective UE; a category of the UE; and a mobility of the UE.
  • the skilled person will appreciate that there are many channel properties according to which UEs may be grouped such as, for example, a delay spread of the channel, a spatial correlation of the channel and/or a coherence time of the channel.
  • UEs may be grouped such as, for example, a number of transmit antennas at the UE and/or a maximum transmission power of the UE.
  • the categories according to which the UEs may be grouped may be define in a 3GPP specification, for example.
  • the UEs may grouped according to two or more of the UE categories described in TS 36.306 v 16.5.0.
  • the mobility of the UE may indicate if or how quickly the UE moves.
  • UEs may be grouped into categories based on whether or not they are moving (e.g. into a stationary category and a moving category) and/or how quickly they are moving (e.g. whether a UE is moving with a speed below a threshold value or moving with a speed above the threshold value).
  • the apparatus 300 may use the same correction for all UEs that are transmitting to a same base station.
  • the base station-side channel estimation which is common to all UE transmitting to the base station, may be the main source of inaccuracies in the channel quality estimate that are to be compensated by the correction.
  • the corrections can be updated more often, leading to better performance.
  • the apparatus 300 is further operable to apply one of the corrections to an SI NR estimate.
  • the apparatus 300 may receive a request 304 to determine an adjusted SINR estimate for a UE (such as the UE 104), in which the request comprises a UE identifier, an associated SINR estimate and a bandwidth.
  • the SINR estimate may be for a channel between the identified UE 104 and a base station, such as the base station 102, for example.
  • the request may be received from the base station 102.
  • the apparatus 300 selects the correction corresponding to the UE 104 and the bandwidth. Thus, for example, if the request 304 indicates that the adjustment is for UE 1 and BW (bandwidth) 2, the apparatus 300 may select the correction associated with UE 1 and BW 2. The apparatus 300 applies (e.g. adds) the selected correction to the SINR estimate comprised in the request 304 to obtain the adjusted SINR 306. The apparatus 300 may send the adjusted SINR 306 to the sender of the request 304 (e.g. to the base station 102).
  • the apparatus 300 is operable to store, update and apply a plurality of corrections for a plurality of UEs and bandwidths. Since the decoding performance information indicates both the UE and bandwidth to which it corresponds, the apparatus 300 can selectively update the correction for a particular UE and bandwidth based on decoding results for that UE and bandwidth only. The apparatus is thus operable to determine UE and bandwidth-specific corrections for SINR estimates.
  • Figure 4 shows the throughput of simulated transmissions from a UE to a base station.
  • the solid line shows the throughput when an existing (legacy) approach for adjusting channel quality estimates is used to determine an adjusted SINR and thus the rank, MCS and bandwidth for uplink transmissions.
  • the dashed line shows the throughput when a bandwidthspecific correction is used to determine the adjusted SINR in accordance with aspects of the present disclosure.
  • using bandwidth-specific corrections to adjust the SNR for link adaptation increases throughput when the SNR is between approximately - 25dB and -15dB. Outside of this range, the new approach provides at least the same performance as existing techniques.
  • the present disclosure thus provides an improved approach for adjusting channel quality estimates that are used for link adaptation for uplink transmissions.
  • bandwidthspecific corrections as described herein, the throughput of uplink transmissions can be increased.
  • a situation may arise in which the apparatus 300 receives a request for a correction for a bandwidth, but the apparatus 300 does not have a correction for that bandwidth.
  • the apparatus 300 may store corrections for fewer bandwidths than could be requested.
  • the correction for a first bandwidth may be determined based on one or more other corrections determined based on decoding results for transmissions with other second bandwidths.
  • the apparatus 300 may determine a correction for a first bandwidth by interpolating between a correction for a second bandwidth and a correction for a third bandwidth, in which the first bandwidth is between the second and third bandwidths.
  • the apparatus 300 may use a linear interpolator, for example.
  • the apparatus 300 may extrapolate from one or more corrections for one or more second bandwidths to determine the correction for the first bandwidth.
  • the apparatus 300 can effectively use the bandwidthspecific corrections which have already been determined to infer the correction for another bandwidth.
  • the apparatus 300 may use the same correction for bandwidths that are similar. This may be advantageous when, for example, the apparatus 300 stores a correction for a second bandwidth, but not a first bandwidth, and the first and second bandwidth differ by less than a predetermined value.
  • the apparatus 300 may thus apply the correction for the second bandwidth to the SINR estimate to obtain the adjusted SINR estimate.
  • the adjusted SINR estimate for a first bandwidth may depend on a decoding result for transmissions made with the second bandwidth, in which the difference between the first and second bandwidth is less than a predetermined value.
  • the apparatus 300 is described as being operable to obtain corrections for a SINR estimate and apply the corrections to SINR estimates, the skilled person will appreciate that, in general, the operation of the apparatus 300 described above may be applied to any channel quality estimate. Thus the apparatus 300 may, in general, be operable to obtain and apply corrections for channel quality estimates.
  • FIG 5 shows a flowchart of a method 500 performed by a base station for determining transmission parameters for transmissions from a wireless device to the base station in a wireless communications network according to examples of the disclosure.
  • the wireless communications network may be the wireless communications network 100 described above in respect of Figure 1 , for example.
  • the base station may be the base station 102 described above in respect of Figure 1 , for example.
  • the wireless device may be any suitable wireless device such as, for example, a UE or a base station.
  • the wireless device may be the UE 104 described above in respect of Figure 1.
  • the wireless device may be another base station in the wireless communications network 100.
  • the method 500 begins in step 502, in which a channel quality estimate is obtained.
  • the channel quality estimate is based on one or more signals transmitted between the base station 102 and the wireless device 104.
  • the channel quality estimate is thus indicative of the quality of a channel between the base station 102 and the wireless device 104.
  • the channel quality estimate may comprise, for example, an SNR or SINR estimate, a mutual information metric, a line of sight metric, or a channel capacity.
  • the skilled person will appreciate that there are various ways of measuring the quality of a channel.
  • the channel quality estimate may be determined based on measurements of one or more reference signals transmitted between the base station 102 and the wireless device 104.
  • the one or more reference signals may, for example, be transmitted from the wireless device 104 to the base station 102 such that measurements of those reference signals indicate the quality of an uplink channel between the wireless device 104 and the base station 102.
  • the one or more reference signals may be transmitted from the base station 102 to the wireless device 104.
  • the channel quality estimate may be based, at least partially, on measurements of one or more downlink reference signals.
  • the one or more reference signals may comprise any suitable reference signals such as, for example, one or more sounding reference signals and/or one or more demodulation reference signals.
  • the channel quality estimate may comprise a channel capacity associated with an SINR or SNR estimate, such as, for example log 2 (l + SINR) in which S/NR is an SINR estimate. More generally, the channel quality estimate may comprise a non-linear function of an SINR or SNR estimate. In another example, the channel quality estimate may be determined by summing a plurality of channel capacities, in which each channel capacity is determined based on an SNR or SINR estimate. This may be appropriate when more than one SNR or SINR estimate is available for a particular bandwidth, for example.
  • the base station 102 may determine the channel quality estimate. For example, the base station 102 may determine the channel quality estimate based on one or more reference signals received from the wireless device 104. Alternatively, the channel quality estimate may be determined elsewhere and sent to the base station 102. For example, the base station 102 may receive the channel quality estimate from the wireless device 104.
  • the base station applies a correction to the channel quality estimate to obtain an adjusted channel quality estimate.
  • the base station 102 may thus, for example, add the correction to the channel quality estimate.
  • the correction may comprise a factor by which the channel quality estimate is to be scaled.
  • the base station 102 may alternatively apply the correction to the channel quality estimate by multiplying the channel quality estimate by the correction.
  • the correction is based on a transmission bandwidth of the wireless device 104 and a decoding result for one or more first transmissions received by the base station 102.
  • the base station 102 may, for example, store a plurality of corrections for the UE for different bandwidths and select a correction from the plurality of corrections based on the transmission bandwidth.
  • the corrections may be determined and selected as described above in respect of Figure 3, for example.
  • the base station 102 may receive the correction from elsewhere.
  • the base station 102 may send a request to another node for a correction for the wireless device 104 and the transmission bandwidth.
  • the other node may be a node in a core network, such as the core network 106.
  • the other node may, as described above in respect of the apparatus 300 for example, store a plurality of corrections.
  • the other node may send the requested correction to the base station 102.
  • the base station 102 may send a request for an adjusted channel quality estimate to another node (e.g. a node in a core network such as the core network 106).
  • the other node may comprise the apparatus 300, for example.
  • the request may include the channel quality estimate, an indication of the wireless device 104 and the transmission bandwidth.
  • the request may correspond to the request 304 described above in respect of Figure 3, for example.
  • the other node may select the correction corresponding to the indicated wireless device 104 and transmission bandwidth and apply the correction to the channel quality estimate to obtain the adjusted channel quality estimate.
  • the other node may send the adjusted channel quality estimate to the base station 102.
  • the base station 102 obtains an adjusted channel quality estimate in step 504.
  • the base station 102 determines one or more transmission parameters for the transmission bandwidth based on the adjusted channel quality estimate.
  • the one or more transmission parameters may comprise one or more of: a rank, a modulation and coding scheme and a bandwidth.
  • the skilled person will be familiar with ways for determining transmission parameters based on a channel quality estimate and thus this will not be discussed in detail here.
  • the one or more transmission parameters may be determined by calculating, based on the adjusted channel quality estimate, Shannon channel capacities of the channel for various combinations of the transmission parameters and selecting a combination of the transmission parameters based on the calculated Shannon channel capacities. For example, the transmission parameters which are expected to result in the highest or largest channel capacity may be selected.
  • the one or more transmission parameters may be determined by comparing the adjusted channel quality estimate with a table of simulation results indicating preferred values of the transmission parameters for respective values of the channel quality estimate.
  • determining the one or more transmission parameters may comprise selecting the transmission bandwidth from a plurality of candidate bandwidths.
  • the candidate bandwidths comprise one or more further bandwidths in addition to the transmission bandwidth.
  • the base station 102 determines a respective adjusted channel quality estimate for each of the candidate bandwidths.
  • the base station 102 also determines respective adjusted channel quality estimates for each of the further bandwidths (e.g. using the same or similar methods as described in respect of step 504).
  • the base station 102 also determines one or more respective transmission parameters for each of the candidate bandwidths based on the respective adjusted channel quality estimates.
  • the base station 102 determines, for each of the candidate bandwidths, a value of one or more metrics based on the transmission parameters determined for that candidate bandwidth.
  • the base station 102 selects the transmission bandwidth from the candidate bandwidths based on the one or more metrics.
  • the base station 102 may compare the metrics for the candidate bandwidths to identify an optimal or best bandwidth.
  • the base station 102 may select the transmission bandwidth from the candidate bandwidths in response to determining that the transmission bandwidth has the highest estimated throughput.
  • the base station 102 may select the transmission bandwidth from the candidate bandwidths in response to determining that the transmission bandwidth has the lowest block error rate.
  • the base station 102 may select the transmission bandwidth in response to determining that the transmission bandwidth has the highest estimated throughput whilst having a block error rate below a threshold value (e.g. a block error rate below 10% or 0.1).
  • a threshold value e.g. a block error rate below 10% or 0.1
  • the base station 102 configures the wireless device 104 to perform one or more second transmissions with the transmission bandwidth according to the transmission parameters determined in step 506.
  • the base station 102 may schedule an uplink grant for the wireless device 104.
  • the uplink grant may comprise one or more resources for the wireless device 104 to use when performing the one or more second transmissions.
  • the base station 102 may send the uplink grant to the wireless device 104.
  • the base station 102 may send the one or more transmissions to the wireless device 104.
  • the wireless device 104 may be operable to perform autonomous transmissions such that the wireless device 104 can transmit without a scheduling grant from the base station 102.
  • the wireless device 104 may perform one or more (autonomous) transmissions in accordance with the one or more transmission parameters received from the base station 102.
  • the base station 102 determines an adjusted channel quality estimate based on a transmission bandwidth of the wireless device 104 and configures the wireless device 104 to transmit according to one or more transmission parameters for the transmission bandwidth.
  • the method 500 can account for bandwidth-dependent errors in the channel quality estimate, providing a more accurate channel quality estimate.
  • Using a more accurate adjusted channel quality estimate enables more effective link adaptation which increases throughput.
  • the method 500 may be performed by any suitable apparatus.
  • the method 500 may be performed by the wireless device 104.
  • the wireless device 104 may, for example, obtain the channel quality estimates by receiving the channel quality estimates from the base station 102.
  • the wireless device 104 may perform measurements on one or more reference signals received from the base station 102 to determine the channel quality estimates.
  • the wireless device 104 may determine the decoding result for one or more first transmissions sent by the wireless device 104 to the base station 102 based on one or more acknowledgements that are received or not received from the base station 102.
  • the wireless device 104 may determine that a decoding attempt has succeeded in response to receiving an acknowledgement from the base station 102.
  • the wireless device 104 may determine that a decoding attempt has failed when no acknowledgement is received within a predefined period of time, for example.
  • the method 500 may be performed by another node (e.g. another apparatus) in the network 100, such as a node in a core network (e.g. the core network 106).
  • the node may receive the channel quality estimate from the base station 102.
  • the node may, for example, configure the wireless device 104 to perform the one or more second transmissions by, for example, sending the one or more transmission parameters to the base station 102.
  • the base station 102 may schedule the second transmission(s) for the wireless device 104 or send the transmission parameters to the wireless device.
  • Figure 6 shows a signalling diagram illustrating signalling between a base station 602 and a wireless device 604 according to aspects of the disclosure.
  • the base station 602 may be the base station 102 described above in respect of Figure 1 , for example.
  • the wireless device 604 may be the UE 104 described above in respect of Figure 1 , for example.
  • the base station 602 determines one or more transmission parameters (e.g. rank, MCS and/or bandwidth) for the wireless device 604 based on an adjusted channel estimate.
  • the adjusted channel estimate comprises a channel quality estimate for the channel between the base station 602 and the wireless device 604 to which a correction has been applied.
  • the correction is based on a transmission bandwidth of the wireless device 604 and a decoding result for one or more transmissions from the wireless device 604 to the base station 602.
  • the one or more transmission parameters may be determined in accordance with steps 502-506 described above in respect of Figure 5, for example.
  • the base station 602 sends an uplink grant to the wireless device 604, scheduling the wireless device to perform one or more first transmissions in accordance with the one or more transmission parameters.
  • the uplink grant may indicate one or more time-frequency resources that the wireless device is to use when performing the one or more first transmissions.
  • the uplink grant may, for example, indicate a particular rank, MCS and/or bandwidth that the wireless device 604 is to use when performing the one or more first transmissions.
  • Step 608 may be performed in accordance with step 508 described above in respect of Figure 5, for example.
  • the wireless device 604 transmits the one or more first transmissions to the base station 602.
  • the base station 602 attempts to decode the first transmissions 612 and determines whether or not the first transmissions are decoded successfully.
  • the base station 602 may use an error check code (e.g. a CRC code) comprised in the one or more first transmissions to determine if there are any decoding errors.
  • the base station updates the correction stored at the base station 602 (e.g. the correction associated with the transmission bandwidth) based on the decoding result.
  • the base station 602 may store a correction for the wireless device 604 and the transmission bandwidth, and update the correction based on the decoding results for transmissions from the wireless device 604 with the transmission bandwidth.
  • the base station 602 may store a plurality of corrections for a plurality of bandwidths.
  • the base station 602 may store a plurality of corrections for a plurality of wireless devices such that, for each wireless device, the base station 602 stores corrections for one or more bandwidths in the plurality of bandwidths.
  • the base station 602 may, for example, store and update the corrections in the same or a similar manner to the apparatus 300 described above in respect of Figure 3, for example.
  • Figure 7 shows a schematic diagram of an apparatus 700 for determining one or more transmission parameters for transmissions from a wireless device to a base station in a wireless communications network according to aspects of the disclosure.
  • the base station may comprise the base station 102 described above in respect of Figure 1.
  • the wireless device may comprise the UE 104 described above in respect of Figure 1 , for example.
  • the apparatus 700 may be, for example, the base station or the wireless device.
  • the apparatus 700 may comprise the apparatus 300 described above in respect of Figure 3, for example.
  • the apparatus may comprise the base station 602 described above in respect of Figure 6, for example.
  • the apparatus 700 comprises processing circuitry (or logic) 702.
  • the processing circuitry 702 controls the operation of the apparatus 700 and can implement the method 500 described above with respect to Figure 5, for example.
  • the processing circuitry 702 can comprise one or more processors, processing units, multi-core processors or modules that are configured or programmed to control the apparatus in the manner described herein.
  • the processing circuitry 702 can comprise a plurality of software and/or hardware modules that are each configured to perform, or are for performing, individual or multiple steps of the method described herein in relation to the apparatus 700.
  • the processing circuitry 702 of the apparatus 700 is operable to obtain a channel quality estimate based on one or more signals transmitted between the base station and the wireless device and apply a correction to the channel quality estimate to obtain an adjusted channel quality estimate, wherein the correction is determined based on a transmission bandwidth of the wireless device and a decoding result for one or more first transmissions received by the base station.
  • the apparatus 700 is further operable to determine one or more transmission parameters for the transmission bandwidth based on the adjusted channel quality estimate and configure the wireless device to perform one or more second transmissions with the transmission bandwidth according to the one or more transmission parameters.
  • the apparatus 700 may comprise a machine-readable storage medium (e.g. a memory) 704.
  • the memory 704 of the apparatus 700 can be configured to store instructions (e.g. program code) that can be executed by the processing circuitry 702 of the apparatus 700 to perform the method described herein in relation to the apparatus 700.
  • the memory 704 of the apparatus 700 can be configured to store any requests, resources, information, data, signals, or similar that are described herein.
  • the processing circuitry 702 of the apparatus 700 may be configured to control the memory 704 of the apparatus 700 to store any requests, resources, information, data, signals, or similar that are described herein.
  • the apparatus 700 may optionally comprise a communications interface 706.
  • the communications interface 706 of the apparatus 700 can be for use in communicating with other nodes, such as other virtual nodes.
  • the communications interface 706 of the apparatus 700 can be configured to transmit to and/or receive from other nodes requests, resources, information, data, signals, or similar.
  • the processing circuitry 702 of the apparatus 700 may be configured to control the communications interface 706 of the apparatus 700 to transmit to and/or receive from other nodes requests, resources, information, data, signals, or similar.
  • the processing circuitry 702, the machine-readable medium 704 and the interfaces 706 are operatively coupled to each other in series.
  • these components may be coupled to each other in a different fashion, either directly or indirectly.
  • the components may be coupled to each other via a system bus or other communication line.
  • the apparatus 700 may comprise a plurality of separate units over which its functionality is distributed.
  • the apparatus 700 may comprise a base station comprising a plurality of units over which the functionality of the base station is distributed.
  • the base station may thus be a distributed (e.g. modular) base station such as, for example, an Open Radio Access Network (O- RAN) node.
  • O- RAN Open Radio Access Network
  • the apparatus 700 may comprise a radio equipment controller (e.g. a baseband processing unit) and one or more remote radio equipment nodes (e.g. radio frequency transceivers).
  • the radio equipment nodes are not co-located with the radio equipment controller and, in particular, the radio equipment nodes may be positioned at a significant distance from the radio equipment controller such that the radio equipment controller can centrally serve a large number of remote radio equipment nodes.
  • the radio equipment controller may be directly or indirectly connected to the remote radio equipment nodes.
  • the radio equipment nodes may be connected to the radio equipment controller via one or more fibre links (e.g. lossless fibre links).
  • the interface between the units in a distributed base station be defined by the Common Public Radio Interface (CPRI), which standardizes the protocol interface between a radio equipment controller and radio equipment nodes in wireless distributed base stations to enable interoperability of equipment from different vendors.
  • CPRI Common Public Radio Interface
  • the radio equipment nodes may be connected to a common CPRI concentrator, for example.
  • the processing circuitry 702 and the machine-readable medium 704 may be comprised in, for example, a radio equipment controller which is configured to control one or more radio equipment nodes forming part of the apparatus 700.
  • the methods described herein e.g. the method 500
  • the processing circuitry 702 and the machine-readable medium 704 may be comprised in one of the radio equipment nodes (e.g. at a transceiver).

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Quality & Reliability (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un appareil de détermination d'un ou de plusieurs paramètres de transmission en liaison montante. L'appareil comprend un processeur et un support lisible par machine, dans lequel le support lisible par machine contient des instructions qui, lorsqu'elles sont exécutées par le processeur, amènent l'appareil à obtenir une estimation de qualité de canal sur la base d'un signal transmis entre une station de base et un dispositif sans fil et à appliquer une correction à l'estimation de qualité de canal pour obtenir une estimation de qualité de canal ajustée. La correction est déterminée sur la base d'une largeur de bande de transmission du dispositif sans fil et d'un résultat de décodage correspondant à une ou plusieurs premières transmissions reçues par la station de base. L'appareil est en outre amené à déterminer un ou plusieurs paramètres de transmission correspondant à la largeur de bande de transmission sur la base de l'estimation de qualité de canal ajustée et à configurer le dispositif sans fil pour effectuer une ou plusieurs secondes transmissions avec la largeur de bande de transmission selon le ou les paramètres de transmission.
PCT/SE2021/050846 2021-08-31 2021-08-31 Procédés et appareils de détermination de paramètres de transmission Ceased WO2023033688A1 (fr)

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PCT/SE2021/050846 WO2023033688A1 (fr) 2021-08-31 2021-08-31 Procédés et appareils de détermination de paramètres de transmission

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110128930A1 (en) * 2008-05-23 2011-06-02 Anders Furuskar Method for Link Adaptation with a Signal Quality Margin on the Bandwidth
EP3314794A1 (fr) * 2015-06-26 2018-05-02 Telefonaktiebolaget LM Ericsson (publ) Procédé et station de base permettant de sélectionner un format de transport
US20190349789A1 (en) * 2017-01-25 2019-11-14 Huawei Technologies Co., Ltd. Outer loop link adaptation adjustment method and apparatus
US20200266918A1 (en) * 2019-02-19 2020-08-20 Samsung Electronics Co., Ltd. System and method for setting link parameters in a wifi link
WO2020192889A1 (fr) * 2019-03-25 2020-10-01 Telefonaktiebolaget Lm Ericsson (Publ) Configuration d'une pluralité d'équipements utilisateurs
US20210036804A1 (en) * 2018-03-13 2021-02-04 Telefonaktiebolaget Lm Ericsson (Publ) Method and network node, for handling link adaption of a channel

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20110128930A1 (en) * 2008-05-23 2011-06-02 Anders Furuskar Method for Link Adaptation with a Signal Quality Margin on the Bandwidth
EP3314794A1 (fr) * 2015-06-26 2018-05-02 Telefonaktiebolaget LM Ericsson (publ) Procédé et station de base permettant de sélectionner un format de transport
US20190349789A1 (en) * 2017-01-25 2019-11-14 Huawei Technologies Co., Ltd. Outer loop link adaptation adjustment method and apparatus
US20210036804A1 (en) * 2018-03-13 2021-02-04 Telefonaktiebolaget Lm Ericsson (Publ) Method and network node, for handling link adaption of a channel
US20200266918A1 (en) * 2019-02-19 2020-08-20 Samsung Electronics Co., Ltd. System and method for setting link parameters in a wifi link
WO2020192889A1 (fr) * 2019-03-25 2020-10-01 Telefonaktiebolaget Lm Ericsson (Publ) Configuration d'une pluralité d'équipements utilisateurs

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