WO2019027495A1 - Commande de puissance de liaison montante multi-utilisateur améliorée pendant une txop - Google Patents

Commande de puissance de liaison montante multi-utilisateur améliorée pendant une txop Download PDF

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Publication number
WO2019027495A1
WO2019027495A1 PCT/US2017/068924 US2017068924W WO2019027495A1 WO 2019027495 A1 WO2019027495 A1 WO 2019027495A1 US 2017068924 W US2017068924 W US 2017068924W WO 2019027495 A1 WO2019027495 A1 WO 2019027495A1
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WO
WIPO (PCT)
Prior art keywords
response
value
rssi
field
target
Prior art date
Application number
PCT/US2017/068924
Other languages
English (en)
Inventor
Ziv AVITAL
Avi MANSOUR
Alexander W. Min
Juan FANG
Laurent Cariou
Ravikumar Balakrishnan
Original Assignee
Intel Corporation
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Intel Corporation filed Critical Intel Corporation
Publication of WO2019027495A1 publication Critical patent/WO2019027495A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/18—TPC being performed according to specific parameters
    • H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
    • H04W52/248—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters where transmission power control commands are generated based on a path parameter
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/06—TPC algorithms
    • H04W52/14—Separate analysis of uplink or downlink
    • H04W52/146—Uplink power control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/18—TPC being performed according to specific parameters
    • H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
    • H04W52/245—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters taking into account received signal strength
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W52/00—Power management, e.g. TPC [Transmission Power Control], power saving or power classes
    • H04W52/04—TPC
    • H04W52/18—TPC being performed according to specific parameters
    • H04W52/24—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters
    • H04W52/247—TPC being performed according to specific parameters using SIR [Signal to Interference Ratio] or other wireless path parameters where the output power of a terminal is based on a path parameter sent by another terminal

Definitions

  • Various embodiments of the invention pertain to controlling transmit power from uplink (UL) wireless communication devices (STAs) to an access point (AP).
  • UL uplink
  • STAs wireless communication devices
  • AP access point
  • each STA may use a different transmission power to achieve this equality of received signal strength at the AP.
  • This transmission power for each STA may be determined by sending a series of 'trigger frames' from the AP (so-called because each trigger frame is intended to trigger a response from the STAs), and receiving a response to each trigger frame from each STA.
  • the TF may include a Target RSSI value that the AP expects to see for responses from the STA, as well as an AP TX power field indicating the transmit power at the AP (common for all STAs).
  • Each STA could then calculate the path loss by determining its measured Received Signal Strength Indication (RSSI) for the received TF. By comparing the Target RSSI; and the estimated path loss, the STA may calculate a transmission strength it should use in its response that would achieve the desired Target RSSI at the AP.
  • RSSI Received Signal Strength Indication
  • estimating the path loss involves inaccurate power measurement errors and normalization instability. So in previous implementations, for a particular STA there may be a variance of several decibels (dBs) from one uplink transmission to the next, even though no actual conditions changed.
  • dBs decibels
  • FIG. 1 shows a diagram of a wireless communications network, according to an embodiment of the invention.
  • FIG. 2 shows a diagram of a wireless communications device, according to an embodiment of the invention.
  • FIG. 3 shows a timing chart of a communications exchange between an AP and multiple STAs, according to an embodiment of the invention.
  • Figs. 4A, 4B, 4C show a format for a trigger frame, according to an embodiment of the invention.
  • Fig. 5 shows a table of mapping for the Target RSSI field, according to an embodiment of the invention.
  • Fig. 6 shows a flow diagram of a method of controlling UL transmit power from a STA to an AP, according to an embodiment of the invention.
  • wireless may be used to describe circuits, devices, systems, methods, techniques, communications channels, etc., that communicate data by using modulated electromagnetic radiation through a non-solid medium.
  • a wireless device may comprise at least one antenna, at least one radio, at least one memory, and at least one processor, where the radio(s) transmits signals through the antenna that represent data and receives signals through the antenna that represent data, while the processor(s) may process the data to be transmitted and the data that has been received. The processor(s) may also process other data which is neither transmitted nor received.
  • an access point is intended to cover devices that schedule and control, at least partially, wireless communications by other devices in the network.
  • An AP may also be known as a network controller (NC), base station (BS), central point (CP), PBSS Control Point (PCP) or any other term that may arise to describe the functionality of a network controller.
  • NC network controller
  • BS base station
  • CP central point
  • PCP PBSS Control Point
  • STA is intended to cover those devices whose wireless communications are at least partially scheduled and controlled by an AP.
  • a STA may also be known as a mobile station (MS), subscriber station (SS), user equipment (UE), or any other term that may arise to describe the functionality of a STA.
  • MS mobile station
  • SS subscriber station
  • UE user equipment
  • STAs may move during such communications, but movement is not required.
  • the term "communicate” is intended to include transmitting and/or receiving. This may be particularly useful in claims when describing the organization of data that is being transmitted by one device and received by another, but the claim can be interpreted to cover the functionality of either one of those devices. Similarly, the bidirectional exchange of data between two devices (both devices transmit and receive during the exchange) may be described as 'communicating', even if only the functionality of one of those devices is being claimed.
  • Various embodiments of the invention may be implemented fully or partially in software and/or firmware.
  • This software and/or firmware may take the form of instructions contained in or on a non-transitory computer-readable storage medium.
  • the instructions may be read and executed by the one or more processors to enable performance of the operations described herein.
  • the instructions may be in any suitable form, such as but not limited to source code, compiled code, interpreted code, executable code, static code, dynamic code, and the like.
  • Such a computer-readable medium may include any tangible non-transitory medium for storing information in a form readable by one or more computers, such as but not limited to read only memory (ROM); random access memory (RAM);
  • the medium may also be external to the device that is to execute the instructions, with the intention that the instructions will eventually be loaded into, and executed by, that device.
  • Fig. 1 shows a diagram of a wireless communications network 100, according to an embodiment of the invention.
  • AP 110 may act as a network controller by coordinating and scheduling communications of the STAs 120, 130, 140, 150, and 160.
  • Five STAs are shown in this network as an example, but other numbers of STAs may also be in the network.
  • Each of devices 110, 120, 130, 140, 150, and 160 may have additional functionality beyond what is described in this document.
  • Fig. 2 shows a wireless communications device, according to an embodiment of the invention.
  • wireless communications device 200 may be an example of any of devices 110, 120, 130, 140, 150, or 160 in Fig. 1.
  • Device 200 may include modules such as, but not limited to, processor 202, memories 204 and 206, sensors 228, network interface 220, antenna(s) 230, graphics display device 210, alphanumeric input device 212 (such as a keyboard), user interface navigation device 214, storage device 216 containing a machine readable medium, power management device 232, and output controller 234.
  • Instructions 224 may be executed to perform the various functions described in this document. They are shown in multiple memories, though this is not a requirement.
  • Communications network 226 may be a wireless network external to the device, through which the device 200 may communicate with other devices.
  • Fig. 3 shows a timing chart of a communications exchange between an AP and multiple STAs, according to an embodiment of the invention.
  • the downlink line indicates transmissions from the AP to the STAs, while the uplink line indicates
  • the sequence may begin with a trigger frame (TF), in which the AP may direct the STAs to respond.
  • TF may contain some common information for all the STAs, as well as some STA-specific information intended for each specific STA.
  • a format for the TF will be shown in Figs. 4A, 4B, 4C.
  • the STAs may each respond simultaneously, using directional transmissions. Each transmission is labeled in Fig. 3 with the STA that it represents (STA 120, STA 130, STA 140, STA 150, STA 160 from Fig. 1). Five transmissions from five STAs are shown, but other embodiments may use other quantities of STAs. After completion of these transmissions from the STAs, a Block
  • Acknowledgement may be transmitted by the AP to indicate successful reception of all transmissions from the STAs.
  • the AP may then transmit another trigger frame to initiate another group of uplink transmissions from the STAs. Upon reception of the uplink responses, the AP may transmit another BA to signify successful reception of those responses.
  • TXOP may contain several of these TF/response/BA sequences, before another TXOP occurs.
  • the first TF in a TXOP may have the STA calculate its uplink power in this way, but subsequent UL transmissions in the same TXOP may have their UL power calculated as a specified variance from the previous UL transmission.
  • the error-prone technique of recalculating path loss for each TF/response exchange may be avoided.
  • Figs. 4A, 4B, 4C show a format for a trigger frame, according to an embodiment of the invention. Numerous fields are shown, but only those directly involved in this process are described.
  • Fig. 4A shows the overall format for the trigger frame.
  • the Common Info field which is shown in more detail in Fig. 4B and includes information of interest to all the STAs.
  • the User Info field (one for each STA) is shown in more detail in Fig. 4C.
  • the Common Info field includes an AP TX Power field, which shows the transmit power from the AP. This value should be the same for all the STAs.
  • the User Info field shows a Target RSSI field, which is intended only for the STA associated with that User and contains an indication of a targeted value for a received signal strength of a response from the STA to the AP.
  • AP TX Power and Target RSSI may be significant in the implementation of embodiments of the invention.
  • Fig. 5 shows a table of mapping for the Target RSSI field, according to an embodiment of the invention.
  • the Target RSSI field has been redefined. With 7 bits, the Target RSSI field may have 127 different values (0 - 127 decimal). In the particular mapping shown, a value in this field of 0-90 may equate to a transmission power of -110 dBm to -20 dBm, with a difference of 1 in this field being the equivalent of 1 dBm. Similarly, a value of 127 in this field may equate to the maximum transmit power for the assigned MCS.
  • a value of 106-126 in this field may equate to a difference of -10 dB to +10 dB from the power of the previous transmission by this same STA.
  • 106 may indicate a change of -10 dB
  • 116 may indicate no change
  • 126 may indicated a change of +10 dB, with a one-to-one distribution of mapping between those points.
  • values 91-105 are not used and are reserved for possible future use. This technique may avoid a calculation of transmit power for any uplink transmission except the first in a TXOP.
  • FIG. 6 shows a flow diagram of a method of adjusting transmit power by a
  • STA in uplink transmissions may transmit simultaneously, but for simplicity only one STA is shown.
  • the other STAs may follow the same procedure.
  • the AP may create a TF.
  • This TF may include a value for the AP's transmit power, a value for the MCS to be used, and an initial value in a Target RSSI field.
  • This TF may then be transmitted at 610. Typically, this transmission may be to multiple STAs, with a separate MCS field and separate Target RSSI field for each STA.
  • a STA may measure the received signal strength of the TF at 615, and subtract that from the AP TX transmit power value to determine path loss at 620.
  • This path loss may then be used to determine the transmit power at 625 that will be used to transmit a response to the TF at 630, with the goal of having the RSSI of that signal, as measured at the AP, be equal to the Target RSSI value indicated in the TF.
  • the AP may measure the actual RSSI of the response received from the STA.
  • this value may be used to determine a new desired RSSI value to send to the STA in the next TF.
  • This desired RSSI may be affected by the actual measured RSSI received from other STAs at the same time as block 635.
  • the AP may calculate a delta based on the difference between the actual measured RSSI at 635 and the Target RSSI of the previous TF as determined at 605. This delta value may then be put into the next TF in the field previously used for Target RSSI, and the TF transmitted to the STA at 650.
  • the STA may adjust its transmit power for the next uplink response by this delta amount. By not using a path loss estimation to determine its transmit power at 655, the STA may avoid the inaccuracies that are inherent in determining path loss.
  • the response may then be transmitted to the AP at 630.
  • the loop of 630-635-640-645-650-655 may be followed for each TF/response exchange (after the first) that take place in the same TXOP.
  • the STA's transmit power may become closer and closer to its optimal value until the delta value equals zero for subsequent TFs in that TXOP.
  • a TXOP only lasts for 5 milliseconds (msec), so external conditions such as movement of the STA, or obstacles moving between the AP and a STA, are not likely to affect the stability of the communications link during a single TXOP.
  • Example 1 includes a wireless communications device having a processor, a memory, and a network interface, wherein: the network interface is to transmit a trigger frame (TF) in a wireless network, the TF to solicit a response from a STA, the TF containing a field to indicate a target value for a received signal strength indication (RSSI) of the response to be measured at the AP; the network interface is to receive the response from the STA and measure an actual RSSI value for the response; the processor and memory are to determine a difference between the target value for the RSSI and the actual RSSI value and place a value indicating the difference in the field; and the network interface is to transmit a second TF to the STA, the second TF containing the value indicating the difference.
  • TF trigger frame
  • RSSI received signal strength indication
  • Example 2 includes the device of example 1, wherein the device is configured to operate as either an OFDMA or MU MEVIO uplink device.
  • Example 3 includes the device of example 1, wherein: the network interface is to receive a second response to the second TF repeat the operation of measuring; the processor and memory are to repeat the operations of determining a difference and placing the difference in the field; and the network interface is to transmit a third TF.
  • Example 4 includes the device of example 1, wherein the TF has a Target
  • Example 5 includes a method of communicating in a wireless network, comprising: transmitting a trigger frame (TF) in a wireless network, wherein the TF is to solicit a response from a STA and the TF contains a field to indicate a target value for a received signal strength indication (RSSI) of the response to be measured at the AP; receiving the response from the STA; measuring an actual RSSI value for the response; determining a difference between the target value for the RSSI and the actual RSSI value; placing a value in the field indicating the difference; and transmitting a second TF to the STA, the second TF containing the value indicating the difference.
  • TF trigger frame
  • RSSI received signal strength indication
  • Example 6 includes the method of example 5, wherein the device is configured to operate as either an OFDMA or MU MEVIO uplink device.
  • Example 7 includes the method of example 5, further comprising: receiving a second response to the second TF; repeating the operations of measuring and determining for the second response; repeating the operation of placing in a third TF; and transmitting the third TF.
  • Example 8 includes the method of example 5, wherein the TF has a Target
  • TXOP Transmit Opportunity
  • Example 9 includes a computer-readable non-transitory storage medium that contains instructions, which when executed by one or more processors result in performing operations comprising: transmitting a trigger frame (TF) in a wireless network, wherein the TF is to solicit a response from a STA and the TF contains a field to indicate a target value for a received signal strength indication (RSSI) of the response to be measured at the AP; receiving the response from the STA; measuring an actual RSSI value for the response; determining a difference between the target value for the RSSI and the actual RSSI value; placing a value in the field indicating the difference; and transmitting a second TF to the STA, the second TF containing the value indicating the difference.
  • TF trigger frame
  • RSSI received signal strength indication
  • Example 10 includes the medium of example 9, wherein the operations further comprise: receiving a second response to the second TF; repeating the operations of measuring and determining for the second response; repeating the operation of placing in a third TF; and transmitting the third TF.
  • Example 11 includes the medium of example 9, wherein the TF has a Target
  • TXOP Transmit Opportunity
  • Example 12 includes a wireless communications device having means to perform the operations of examples 5-8.
  • Example 13 includes a wireless communications device having a processor, a memory, and a network interface, wherein: the network interface is to receive a first trigger frame (TF) from an AP in a wireless network and determine a received signal strength of the received first TF; the processor and memory are to read an AP TX Power field from the first TF, determine a path loss, and determine a first transmit power level for a response to the first TF, the first transmit power level based at least partly on the AP TX Power and the path loss; the network interface is to transmit the response to the AP at the first transmit power level; the network interface is to receive a second TF from the AP, the second TF containing a delta value in a Target RSSI field; the processor and memory are to determine a second transmit power level by combining the delta value with the first transmit power level; and the network interface is to transmit a second response to the AP at the second transmit power level.
  • TF trigger frame
  • Example 14 includes the device of example 13, wherein the device is configured to operate as either an OFDMA or MU MEVIO uplink device.
  • Example 15 includes the device of example 13, wherein the TF has a Target
  • TXOP Transmit Opportunity
  • Example 16 includes a method of communicating in a wireless network, comprising: receiving a first trigger frame (TF) from an AP in a wireless network and determining a received signal strength of the received first TF; reading an AP TX Power field from the first TF, determining a path loss, and determining a first transmit power level for a response to the first TF, the first transmit power level based at least partly on the AP TX Power and the path loss; transmitting the response to the AP at the first transmit power level; receiving a second TF from the AP, the second TF containing a delta value in a Target RSSI field; determining a second transmit power level by combining the delta value with the first transmit power level; and transmitting a second response to the AP at the second transmit power level.
  • TF trigger frame
  • Example 17 includes the method of example 16, wherein said transmitting the response and said transmitting the second response comprise transmitting in a manner compatible with either OFDMA or MU MEVIO uplink.
  • Example 18 includes the method of example 16, wherein the TF has a Target
  • TXOP Transmit Opportunity
  • Example 19 includes a computer-readable non -transitory storage medium that contains instructions, which when executed by one or more processors result in performing operations comprising: receiving a first trigger frame (TF) from an AP in a wireless network and determining a received signal strength of the received first TF; reading an AP TX Power field from the first TF, determining a path loss, and determining a first transmit power level for a response to the first TF, the first transmit power level based at least partly on the AP TX Power and the path loss; transmitting the response to the AP at the first transmit power level; receiving a second TF from the AP, the second TF containing a delta value in a Target RSSI field; determining a second transmit power level by combining the delta value with the first transmit power level; and transmitting a second response to the AP at the second transmit power level.
  • TF trigger frame
  • Example 20 includes the medium of example 19, wherein said transmitting the response and said transmitting the second response comprise transmitting in a manner compatible with either OFDMA or MU MEVIO uplink.
  • Example 21 includes the medium of example 19, wherein the TF has a Target
  • TXOP Transmit Opportunity
  • Example 22 includes a wireless communications device having means to perform the operations of examples 16-18.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

Dans un réseau sans fil multi-utilisateur (par exemple, un réseau conforme à la norme sans fil IEEE 802.11ax), un module de commande de puissance de liaison montante dans un point d'accès peut déterminer des paramètres de RSSI et de MCS cibles pour chaque STA, transmettre ces valeurs dans une trame de déclenchement, et attendre les réponses sollicitées à partir des STA indiquées. Sur la base du RSSI mesuré dans ces réponses à partir de chaque STA, l'AP peut ensuite placer des valeurs dans chaque RSSI cible, en dirigeant la STA afin d'ajuster sa puissance de transmission précédente vers le haut ou vers le bas par une quantité delta spécifiée dans la transmission de liaison montante suivante. Après quelques passages, la puissance transmise peut se stabiliser jusqu'à une valeur d'état stable.
PCT/US2017/068924 2017-08-04 2017-12-29 Commande de puissance de liaison montante multi-utilisateur améliorée pendant une txop WO2019027495A1 (fr)

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US201762541478P 2017-08-04 2017-08-04
US62/541,478 2017-08-04

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017034081A1 (fr) * 2015-08-21 2017-03-02 엘지전자(주) Procédé et dispositif de transmission de données dans un système de communication sans fil
WO2017040788A1 (fr) * 2015-09-03 2017-03-09 Qualcomm Incorporated Régulation de puissance dans des réseaux sans fil
WO2017044696A1 (fr) * 2015-09-10 2017-03-16 Interdigital Patent Holdings, Inc. Procédés et procédures de commande de puissance multi-utilisateur
US20170135046A1 (en) * 2015-11-05 2017-05-11 Ilan Sutskover Transmit power control for uplink transmissions
US20170181102A1 (en) * 2015-12-17 2017-06-22 Qualcomm Incorporated Power control for uplink transmissions

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017034081A1 (fr) * 2015-08-21 2017-03-02 엘지전자(주) Procédé et dispositif de transmission de données dans un système de communication sans fil
WO2017040788A1 (fr) * 2015-09-03 2017-03-09 Qualcomm Incorporated Régulation de puissance dans des réseaux sans fil
WO2017044696A1 (fr) * 2015-09-10 2017-03-16 Interdigital Patent Holdings, Inc. Procédés et procédures de commande de puissance multi-utilisateur
US20170135046A1 (en) * 2015-11-05 2017-05-11 Ilan Sutskover Transmit power control for uplink transmissions
US20170181102A1 (en) * 2015-12-17 2017-06-22 Qualcomm Incorporated Power control for uplink transmissions

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