WO2016085440A1 - Détermination de période de rétroaction d'informations d'état de canal en fonction d'un état de mobilité de dispositif de communication sans fil - Google Patents

Détermination de période de rétroaction d'informations d'état de canal en fonction d'un état de mobilité de dispositif de communication sans fil Download PDF

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Publication number
WO2016085440A1
WO2016085440A1 PCT/US2014/067009 US2014067009W WO2016085440A1 WO 2016085440 A1 WO2016085440 A1 WO 2016085440A1 US 2014067009 W US2014067009 W US 2014067009W WO 2016085440 A1 WO2016085440 A1 WO 2016085440A1
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Prior art keywords
wireless communication
communication device
wap
csi feedback
csi
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PCT/US2014/067009
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English (en)
Inventor
Souvik SEN
Li Sun
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Hewlett Packard Enterprise Development Lp
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Priority to PCT/US2014/067009 priority Critical patent/WO2016085440A1/fr
Publication of WO2016085440A1 publication Critical patent/WO2016085440A1/fr

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/10—Scheduling measurement reports ; Arrangements for measurement reports
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0621—Feedback content
    • H04B7/0626—Channel coefficients, e.g. channel state information [CSI]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/06—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station
    • H04B7/0613—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission
    • H04B7/0615—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal
    • H04B7/0619—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas at the transmitting station using simultaneous transmission of weighted versions of same signal using feedback from receiving side
    • H04B7/0636—Feedback format
    • H04B7/0645—Variable feedback
    • H04B7/0647—Variable feedback rate
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W24/00—Supervisory, monitoring or testing arrangements
    • H04W24/02—Arrangements for optimising operational condition
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
    • H04W88/08—Access point devices

Definitions

  • Wireless communication devices such as certain smartphones, tablets, laptops, and other wireless clients can connect to a Wireless Access Point (WAP) of a wired network via Wi-Fi, cellular, or other wireless communication techniques and standards.
  • WAP Wireless Access Point
  • CSI Channel State Information
  • CSI of a wireless channel connecting a wireless communication device to a WAP, such as channel metrics for a given frequency domain, can be recorded and analyzed in order to determine operating parameters of the wireless communication device and WAP.
  • FIG. 1 illustrates a wireless access point, according to an example.
  • FIG. 2 illustrates a bar graph that illustrates changes to throughput for various mobility states at different feedback periods under single user (SU) beamforming, according to an example.
  • FIG. 3 illustrates a line graph that compares throughput based on different mobility states under SU-beamforming, according to an example.
  • FIG. 4 illustrates a bar graph that illustrates changes to throughput for various mobility states at different feedback periods under multiple user multiple input multiple output (MU-MIMO) beamforming, according to an example.
  • MU-MIMO multiple user multiple input multiple output
  • FIG. 5 illustrates a line graph that compares throughput based on different mobility states under MU-MIMO beamforming, according to an example.
  • FIG. 6 illustrates a method, according to an example.
  • FIG. 7 illustrates a computing system, according to an example.
  • FIG. 8 illustrates a wireless access point in communication with a wireless communication device using a wireless channel, according to an example.
  • Channel State Information (CSI) of a wireless channel connecting a wireless communication device to a WAP can be recorded and analyzed in order to determine operating parameters of the wireless communication device and WAP.
  • communication parameters for wireless transmission can be determined based on changes to CSI based on changes in antenna placement, nearby obstructions, nearby interfering electronic devices, weather conditions, operating radio frequency, etc.
  • Infrequent CSI feedback may result in stale CSI and consequent performance loss.
  • overly frequent CSI feedback may be disadvantageous because such feedback is typically transmitted at a low bit-rate and may consume significant channel airtime.
  • managing the CSI feedback period between a wireless communication device and a WAP can be important to achieving a desired performance of a wireless link.
  • CSI for a wireless channel can change rapidly based on the mobility state of the wireless communication device.
  • a stationary device can have a more "stable" wireless channel compared to a device being moved from room to room in a building.
  • it can be advantageous to tune a CSI feedback period based on the mobility state of the wireless communication device— for example, polling a stationary wireless communication device for CSI feedback less frequently than a moving wireless communication device.
  • Certain implementations of the present disclosure are directed to such techniques. It has been found that by using certain techniques described herein, a median throughput for a wireless communication device can be improved by 33% compared to a default scheme that uses a statically configured CSI feedback period.
  • FIG. 1 illustrates a WAP 10 according to an example.
  • WAP 10 includes a mobility determination module 12 to periodically determine a mobility state of a wireless communication device in wireless communication with WAP 10, a CSI feedback period determination module 14 to determine a CSI feedback period based on the determined mobility state of the wireless communication device, and a CSI feedback polling module 16 to periodically poll the wireless communication device for CSI feedback according to the determined CSI feedback period.
  • wireless communication device as used herein is intended to broadly refer to any suitable device that can be subject to multiple mobility states (e.g., static, environmental, macro-, and micro-mobility states, etc., as further described herein).
  • Such wireless communication devices can include, for example, suitable smartphones, tablets, PCs, laptops, etc.
  • Suitable wireless communication devices can, for example, include hand-held devices that can be carried by an operator, as well as devices that can be subject to changing mobility states through other means, examples of which are described below.
  • WAP 10 can, for example, be in the form of a fixed or stationary device that allows one or more wireless communication devices to connect to a wired network using Wi-Fi, or other wireless transmission protocols, such as cellular transmission protocols.
  • WAP 10 can, for example, connect to a router (e.g., via a wired network) as a standalone device.
  • WAP 10 can be combined with a router in a single housing.
  • WAP 10 can be in the form of a cellular base station, such as a Macrocell, Microcell, Picocell, or Femtocell.
  • FIG. 1 illustrates WAP 10 in the form of functional modules that can, for example, be operative to execute one or more steps of methods described above.
  • module refers to a combination of hardware (e.g., a processor such as an integrated circuit or other circuitry) and software (e.g., machine- or processor- executable instructions, commands, or code such as firmware, programming, or object code).
  • a combination of hardware and software can include hardware only (i.e., a hardware element with no software elements), software hosted at hardware (e.g., software that is stored at a memory and executed or interpreted at a processor), or at hardware and software hosted at hardware.
  • modules are intended to mean one or more modules or a combination of modules.
  • Each module of WAP 10 can include one or more machine-readable storage mediums (such as one or more storage mediums described below with respect to FIG. 7) and one or more computer processors (such as one or more processors described below with respect to FIG.7).
  • software that provides the functionality of modules on WAP 10 can be stored on a memory of a computer to be executed by a processor of the computer.
  • mobility determination module 12 can be used to periodically determine a mobility state of a wireless communication device in wireless communication with WAP 10. In some implementations, mobility determination module 12 can be used to determine whether the wireless communication device is in a static mobility state, an environmental mobility state, a micro-mobility state, or a macro-mobility state. It is appreciated that fewer or additional potential mobility states can be supported and determined.
  • static mobility state may refer to a state in which there is no movement between the wireless communication device and WAP 10 that affects a wireless channel between the wireless communication device and WAP 10.
  • An example of a static state may include a user that is working on a laptop in a home environment.
  • the term "environmental mobility state" as used herein may refer to movement of an object and/or a person that is external to the wireless communication device and/or WAP 10 that affects the wireless channel between the wireless communication device and WAP 10.
  • the wireless communication device and WAP 10
  • An example of environmental mobility may include an airport terminal in which movement of an object (e.g., various machines and luggage) and/or a person that is external to the wireless communication device and/or WAP 10 affects a wireless channel between the wireless communication device and WAP 10.
  • micro-mobility state may refer to a relatively smaller amount of movement or constrained movement between the wireless communication device and WAP 10 compared to the macro-mobility.
  • micro-mobility and macro- mobility may include movement of the wireless communication device and/or WAP 10 that affects the wireless channel between the wireless communication device and WAP 10.
  • the wireless communication device may be considered to be moving without extensive change in the location of the wireless communication device. For example, when a user that is sitting uses a smartphone to make a call, the smartphone may include limited movement. The limited movement may nevertheless be sufficient to affect (i.e., change) the wireless channel between the wireless communication device and WAP 10.
  • the term "macro-mobility state" as used herein may refer to a situation in which the wireless communication device may be considered to be moving with extensive change in the location of the wireless communication device. For example, when a user that is walking uses a smartphone to make a call, the smartphone may include relatively extensive movement. The relatively extensive movement will likely affect (i.e., change) the wireless channel between the wireless communication device and WAP 10.
  • the various mobility states are intended to refer to the relationship between the wireless communication device, WAP 10 and their environment, and not only the wireless communication device.
  • this description may informally refer to the "wireless communication device being in a macro-mobility state" it is appreciated that this is intended to mean that the relationship between the wireless communication device, WAP 10, and the environment can include: (1) the wireless communication device being moved relative to a static WAP 10, (2 ⁇ WAP 10 being moved relative to a static wireless communication device, and (3) both WAP 10 and the wireless communication device being moved with relative movement therebetween.
  • references to the "wireless communication device being in the static mobility state” can include situations in which the wireless communication device is being moved, but with little or no movement relative to WAP 10 (e.g., a laptop in a moving vehicle in wireless communication with a WAP that is also in the moving vehicle).
  • mobility determination module 12 can include a movement determination module to determine movement between the wireless communication device and WAP 10.
  • Information regarding movement between the wireless communication device and WAP 10 can, for example, be recorded using one or more sensors integrated in or connected to the wireless communication device.
  • sensors can include Global Positioning System (GPS) sensors, accelerometers, and gyroscopes.
  • PHY physical
  • CSI between the wireless communication device and WAP 10 can be used to determine whether the wireless communication device is in a static state or in a mobile state (e.g., under environmental mobility, or under micro-mobility or macro-mobility).
  • time-of-flight (ToF) measurements may be used to distinguish between mobility states of a wireless communication device.
  • mobility determination module 12 can include a correlation value comparison module to compare a correlation value (i.e., a CSI correlation value) to a static state value threshold and to an environmental state value threshold in order to distinguish between static and environmental mobility states.
  • a correlation value i.e., a CSI correlation value
  • CSI can be considered a measure of a wireless channel between a WAP and a wireless communication device, if the wireless channel changes relatively quickly, the correlation of the current CSI and a past CSI can be relatively low. If the wireless channel remains stable because the wireless communication device is in a static mode, the correlation value can be relatively high.
  • mobility determination module 12 can compare information regarding the wireless communication device and/or the wireless channel between the wireless communication device and WAP 10. For example, in response to a determination that the correlation value is greater than a static value threshold, mobility determination module 12 can designate the wireless communication device as being in the static mobility state relative to WAP 10. In response to a determination that the correlation value is less than the static value threshold and greater than the environmental value threshold, mobility determination module 12 can designate the wireless communication device as being under environmental mobility relative to WAP 10. Likewise, in response to a determination that the correlation value is less than the environmental value threshold, the movement designation module may designate the wireless communication device as being under micro-mobility or macro-mobility relative to WAP 10.
  • WAP 10 includes a CSI feedback period determination module 14 to determine a CSI feedback period based on the determined mobility state of the wireless communication device.
  • the CSI feedback period can, for example, indicate a period for WAP 10 to poll the wireless communication device for CSI between WAP 10 and the wireless communication device.
  • CSI feedback period determination module 14 can, for example, determine a longer CSI feedback period for a more predictable mobility state of the wireless communication device and can, for example, determine a shorter CSI feedback period for a less predictable mobility state of the wireless communication device.
  • CSI feedback period determination module 14 can assign a CSI feedback period of about 200 ms when it is determined that the wireless communication device is in a static mobility state, a CSI feedback period of about 50 ms when it is determined that the wireless communication device is in an environmental mobility state, a CSI feedback period of about 10 ms when it is determined that the wireless communication device is in a micro-mobility state, and a CSI feedback period of about 5 ms when it is determined that the wireless communication device is in a macro-mobility state.
  • CSI feedback polling module 16 of WAP 10 is configured to periodically poll, according to the CSI feedback period, the wireless communication device for CSI feedback regarding the wireless communication channel between WAP 10 and the wireless communication device.
  • CSI feedback polling module 16 can include one or more antennae 40 to wirelessly poll the wireless communication device.
  • CSI feedback polling module 16 can include a transmitter, which can, for example, be in the form of a first antenna, to transmit signals to the wireless communication device and a receiver, which can, for example, be in the form of a second antenna, to receive signals from the wireless communication device.
  • a combined transmitter-receiver (e.g., a transceiver) can be used to transmit signals to and receive signals from the wireless communication device. It is appreciated that other suitable wireless communication polling technologies can be used.
  • CSI can be considered a measurement of the wireless channel between WAP 10 and the wireless communication device.
  • the CSI feedback packet may consist of a real and imaginary value (e.g., quantized into a value up to 8 bits) for each sub-carrier and transmit-receive antenna pair.
  • CSI can, for example, include information directed to channel metrics for a wireless channel in the frequency domain.
  • CSI can, for example, represent PHY layer information that reports channel metrics for a wireless channel between the wireless communication device and WAP 10 in the frequency domain.
  • CSI can, for example, capture the delay and attenuation of different signal paths traversing from the wireless communication device to WAP 10.
  • a quality "Y" of the received symbol at WAP 10 can depend on the CSI "H” as follows:
  • CSI can represent the channel matrix for the wireless channel, and n may represent a noise vector.
  • CSI may be represented as a vector which includes complex numbers representing channel gain for every subcarrier (e.g., sub-channel) and for every transmit-receive antenna pair. For example, assuming WAP 10 includes 52 subcarriers (i.e., m subcarriers) and 3 antennas (i.e., p antennas), in this example, CSI may be represented as a complex vector of size 52 x 3 (i.e., m x p). This is but one example of CSI being determined as a function of a number of subcarriers and antennas supported by WAP 10.
  • WAP 10 can use the determined mobility state of the wireless communication device in order to select parameters for communication with the wireless communication device.
  • the wireless channel may be predicted to remain stable, and hence, wireless protocol selection instructions can utilize past transmission history to select an appropriate wireless protocol.
  • wireless protocol selection instructions can limit the length of past history that a wireless protocol may refer to based on the intensity of movement of the wireless communication device (and/or WAP 10).
  • WAP 10 can supplemental CSI feedback received from the wireless communication device with other data, such as feedback determined by WAP 10 itself or independent feedback sensors.
  • CSI acted upon by WAP 10 can be combined data from multiple sources, such as the wireless communication device, WAP 10 itself, and other wireless communication devices in wireless communication with WAP 10.
  • FIG. 2 is a bar graph that illustrates an average throughput in megabits per second (Mbps) for different mobility states and different CSI feedback periods for Single User (SU) beamforming.
  • Beamforming is a wireless communication technique that can, for example, be used to improve a performance of a wireless link by exploiting multiple antennas of a WAP.
  • SU beamforming in IEEE 802.11 ⁇ can be used to precode a single packet across multiple antennas at the WAP so that the signals from different antennas combine coherently at the wireless communication device.
  • the bar graph of FIG. 2 illustrates that in static scenarios, a shorter CSI feedback period can be detrimental to overall throughput. This is because the wireless channel can be predicted to generally remain stable in static scenarios. As a result, frequent CSI feedback only adds to the overhead without necessarily resulting in better CSI estimates. In contrast, if the wireless communication device is mobile (as shown for example for the micro- and macro-mobility state values in FIG. 2), the wireless channel can change quickly and CSI feedback should be provided more frequently.
  • the values in the graph of FIG. 2 were attained during experimental testing using 802.1 la/b/g/n protocols.
  • CSI traces at three locations were collected using laptops containing Atheros 9390 chipset and a single receiving antenna.
  • the Wi-Fi driver at the WAP was modified to vary the feedback period based on the mobility state of the wireless communication device— 200 ms for static, 50 ms for environmental mobility, 10 ms for micro-, and 5 ms for macro-mobility.
  • An Atheros driver of the laptop was configured to report the CSI values for every transmitter-receiver antenna pair for each data packet received from the WAP.
  • Transmitter-receiver antenna pairs were provided for four wireless communication devices in four different mobility states— static, environmental, micro- and macro- mobility states. Thereafter, data packets were sent from the WAP to each laptop every 500 micro-second. The series of CSI values were fed to an emulator written in C. The emulator simulates constant bit rate (CBR) traffic between the WAP and the wireless communication devices and reports the throughput for each wireless communication device.
  • CBR constant bit rate
  • SU-beamforming was evaluated using adaptive CSI feedback in a testbed at 300 different mobile links by injecting download Transfer Control Protocol (TCP) traffic from the WAP.
  • TCP download Transfer Control Protocol
  • FIG. 3 is a line graph that illustrates cumulative distribution functions (CDF) of throughput gain for 300 different links subjected to a variety of mobility states using transmit beamforming.
  • CDF cumulative distribution functions
  • the description of the bar graph of FIG. 2 provides further information regarding this configuration.
  • the line graph of FIG. 3 compares values attained when adaptive CSI feedback is used versus using a static feedback period (200 ms) scheme. Performance gain is evident for all varieties of mobility states. For example, FIG. 3 shows that by selecting a CSI feedback period based on mobility, it is possible to improve the median throughput by 33% over a default Atheros scheme which uses a statically configured 200 ms CSI feedback period.
  • FIG.4 is a bar graph that illustrates an average throughput in Mbps for different mobility states and different CSI feedback periods for Multi-User Multiple-Input Multiple-Output (MU-MIMO) beamforming.
  • MU-MIMO beamforming under IEEE 802.1 lac can be used to precode packets for different wireless communication devices so that the packets can be transmitted simultaneously to multiple wireless communication devices.
  • FIG.4 shows that MU-MIMO is also sensitive to stale CSI values. As illustrated in FIG. 4, mobility only affects the performance of the mobile wireless communication device and does not impact the static wireless communication devices noticeably.
  • MU-MIMO precoding is used to ensure that signals from all the transmit antennas combine coherently at each intended wireless communication device, which is only related to the channel between the WAP and the respective wireless communication device. Therefore it is possible to improve MU-MIMO performance by using different CSI feedback periods that are commensurate to the mobility states of individual wireless communication devices.
  • the MU-MIMO emulator sampled the CSI traces every feedback period.
  • the CSI feedback period was chosen on a per-wireless communication device basis depending on the wireless communication device's mobility state— 200 ms for static, 50 ms for environmental mobility, 10 ms for micro-, and 2 ms for macro-mobility, compared to a default scheme of 200 ms CSI feedback period for all states.
  • the emulator used Atheros RA for rate control and does not employ aggregation.
  • FIG. 5 is a line graph that illustrates a cumulative distribution functions (CDF) of throughput gain subjected to a variety of mobility states for MU-MIMO. Further details regarding the configuration used to attain the values of FIG. 5 is provided with respect to the description of FIG. 4. The graph compares values attained when adaptive CSI feedback is used versus when a static feedback period (200 ms) scheme is used. Performance gain is evident for all varieties of mobility, with the most gains for wireless communication devices under macro-mobility. For example, on average, the adaptive CSI feedback scheme was shown to improve MU-MIMO' s network throughput by close to 40%.
  • CDF cumulative distribution functions
  • FIG. 6 is a flowchart for a method 18 of operating a WAP in accordance with the disclosure herein.
  • the description of method 18 and its component steps make reference to elements of WAP 10 and an example wireless communication device for illustration, however, it is appreciated that this method can be used or otherwise applicable for any suitable devices.
  • one or more steps of method 18 can be applied to an alternative WAP or a device that can remotely control a WAP.
  • one or more determination steps of method 18 can be performed by a remote computer that is in wired (or wireless) communication with WAP 10.
  • Method 18 includes a step 20 of periodically determining, with a processor of WAP 10, a mobility state of a wireless communication device in wireless communication with WAP 10. This determination can, for example, be based on movement between the wireless communication device and WAP 10 as described above with respect to mobility determination module 12 of WAP 10. As but one example described above with respect to mobility determination module 12 of FIG. 1, a mobility state of the wireless communication device can be determined using accelerometer values of the wireless communication device. As another example described above with respect to mobility determination module 12 of FIG. 1, a mobility state of the wireless communication device can be determined based on CSI of the wireless channel between the wireless communication device and WAP 10. It is appreciated that any suitable aspects of mobility determination module 12 can be applied to step 20 of method 18.
  • Method 18 includes a step 22 of determining, with the processor of WAP 10, a CSI feedback period based on the determined mobility state of the wireless communication device.
  • the CSI feedback period indicates a period for WAP 10 to poll the wireless communication device for CSI between WAP 10 and the wireless communication device.
  • the period to determine the mobility state of the wireless communication device can be assigned or determined separately from the CSI feedback period.
  • the period to determine the mobility state of the wireless communication device can, in some implementations, be more frequent than the CSI feedback period.
  • the period to determine the mobility state of the wireless communication device can be less frequent than the CSI feedback period.
  • the period to determine the mobility state of the wireless communication device is about 512 ms and the CSI feedback period can range from about 5 ms to about 200 ms. It is appreciated that any suitable aspects of CSI feedback period determination module 14 can be applied to step 22 of method 18.
  • determining the CSI feedback period based on the determined mobility state of the wireless communication device includes: (1) assigning a CSI feedback period of about 200 ms when it is determined that the wireless communication device is in a static mobility state, (2) assigning a CSI feedback period of about 50 ms when it is determined that the wireless communication device is in an environmental mobility state, (3) assigning CSI feedback period of about 10 ms when it is determined that the wireless communication device is in a micro-mobility state, and (4) assigning a CSI feedback period of about 5 ms when it is determined that the wireless communication device is in a macro-mobility state.
  • Method 18 includes a step 24 of periodically polling, with WAP 10, the wireless communication device for CSI between WAP 10 and the wireless communication device according to the CSI feedback period.
  • the wireless communication device can be polled using an antenna of WAP 10. It is appreciated that any suitable aspects of CSI feedback polling module 16 can be applied to step 24 of method 18.
  • FIG. 7 illustrates an example of a computing system 26 that can execute WAP-related instructions in accordance with the present disclosure.
  • Computing system 26 can, for example, be used to provide WAP functionality by executing one or more steps of method 18 described above with respect to FIG. 6 and/or to provide functionality of WAP 10 described above with respect to FIG. 1.
  • the description of computing system 26 refers to WAP 10 and an example wireless communication device for illustration, however, it is appreciated that computing system 26 can be used with any suitable devices.
  • Computing system 26 includes a processor 28 and machine-readable storage medium 30 as described further below. It is appreciated that computing system 26 can include additional elements, such as input/output (I/O) devices, a communication interface, etc.
  • I/O input/output
  • Computing system 26 can be in the form of a WAP or other suitable wireless transmitter.
  • WAP 10 any suitable wireless transmitter.
  • one or hardware or software elements for WAP 10 described herein may be implemented in computing system 26.
  • software that provides the functionality of WAP 10 can be stored on machine-readable storage medium 30 of computing system 26 to be executed by processor 28 of computing system 26.
  • Processor 28 of computing system 26 can, for example, be in the form of a central processing unit (CPU), a semiconductor-based microprocessor, a digital signal processor (DSP) such as a digital image processing unit, other hardware devices or processing elements suitable to retrieve and execute instructions stored in medium 30, or suitable combinations thereof.
  • processor 28 can, for example, include single or multiple cores on a chip, multiple cores across multiple chips, multiple cores across multiple devices, or suitable combinations thereof.
  • Processor 28 can be functional to fetch, decode, and execute instructions as described herein.
  • processor 28 can, for example, include at least one integrated circuit (IC), other control logic, other electronic circuits, or suitable combination thereof that include a number of electronic components for performing the functionality of instructions stored on medium 30.
  • IC integrated circuit
  • Processor 28 can, for example, be implemented across multiple processing units and instructions may be implemented by different processing units in different areas of computing system 26.
  • Medium 30 of computing system 26 can, for example, be in the form of a non-transitory machine-readable storage medium, such as a suitable electronic, magnetic, optical, or other physical storage apparatus to contain or store information such as CSI feedback period determination instructions 32 and CSI polling instructions 34.
  • Such instructions can be machine readable instructions executable by processor 28 such that computing system 26 is operative to perform one or more functions described herein, such as those described above with respect to method 18.
  • Medium 30 can, for example, be housed within the same housing as processor 28 for computing system 26, such as within a computing tower case for computing system 26. In some implementations, medium 30 and processor 28 are housed in different housings.
  • the term "machine-readable storage medium” can, for example, include Random Access Memory (RAM), flash memory, a storage drive (e.g., a hard disk), any type of storage disc (e.g., a Compact Disc Read Only Memory (CD-ROM), any other type of compact disc, a DVD, etc.), and the like, or a combination thereof.
  • medium 30 can correspond to a memory including a main memory, such as a Random Access Memory (RAM), where software may reside during runtime, and a secondary memory.
  • RAM Random Access Memory
  • the secondary memory can, for example, include a nonvolatile memory where a copy of machine-readable instructions are stored. It is appreciated that instructions and data can be stored on separate machine-readable storage mediums and multiple mediums can be treated as a single medium 30 for purposes of description.
  • CSI feedback period determination instructions 32 can, for example, instruct computing system 26 to determine a CSI feedback period based on a pre-determined mobility state of a wireless communication device in wireless communication with computing system 26.
  • the CSI feedback period can, for example, indicate a period for computing system 26 to poll the wireless communication device for CSI between computing system 26 and the wireless communication device. It is appreciated that any suitable aspects of CSI feedback period determination module 14 of FIG. 1 or step 22 of method 18 can be incorporated in CSI feedback period determination instructions 32.
  • CSI polling instructions 34 can, for example, instruct computing system 26 to periodically poll the wireless communication device for CSI between the computing system 26 and the wireless communication device according to the CSI feedback period. It is appreciated that any suitable aspects of CSI feedback polling module 16 of FIG. 1 or step 24 of method 18 can be incorporated in CSI polling instructions 34.
  • FIG. 8 illustrates an example WAP 10 in wireless communication with a wireless communication device 36 via wireless channel 38.
  • the WAP of FIG. 8 and representative components thereof are labelled using the same numbers as the WAP of FIG. 1.
  • the WAP of FIG. 8 can include additional, alternative, or fewer components compared to the WAP of FIG. 1.
  • the specific parameter selection functionality of the WAP of FIG. 8 may not necessarily be included in the WAP of FIG. 1.
  • both WAPs may include such functionality.
  • WAP 10 includes an antenna 40, a processor 28, machine-readable storage medium 30, CSI feedback period determination instructions and CSI polling instructions 34. These components and their functionality are described in further detail above with respect to FIGs 1 and 7.
  • WAP 10 can include parameter selection instructions 42 to select appropriate parameters based on the mobility state of wireless communication device 36.
  • parameter selection instructions 42 can be in the form of wireless protocol selection instructions to select an appropriate wireless protocol for wireless channel 38 based on whether wireless communication device 36 is in the static mobility state relative to WAP 10, whether there is environmental mobility between wireless communication device 36 and WAP 10, and whether there is micro-mobility or macro-mobility between wireless communication device 36 and WAP 10.
  • parameter selection instructions 42 can be applied by a corresponding module incorporating a combination of hardware (e.g., a processor such as an integrated circuit or other circuitry) and software (e.g., machine- or processor-executable instructions, commands, or code such as firmware, programming, or object code).
  • hardware e.g., a processor such as an integrated circuit or other circuitry
  • software e.g., machine- or processor-executable instructions, commands, or code such as firmware, programming, or object code.
  • Parameter selection instructions 42 can execute a precoding operation for beamforming that combines outgoing packets and carefully choose weights based on CSI between WAP 10 and wireless communication device 36.
  • movement between wireless communication device 36 and WAP 10 may result in variations in the quality of wireless channel 38 between the wireless communication device and WAP 10, data transmission loss, and the need to load balance due to roaming of wireless communication device 36.
  • different wireless networking protocols may be used for communication between wireless communication device 36 and WAP 10.
  • static scenarios historical information may be leveraged to select appropriate protocols for communication between wireless communication device 36 and WAP 10.
  • some of the historical information may not be useful, and different protocols may be used to avoid transmission loss.
  • the mobility state of wireless communication device 36 may be classified in a variety of mobility states to thus provide for selection of an appropriate wireless networking protocol for communication between wireless communication device 36 and WAP 10.
  • wireless communication device 36 is under macro-mobility and is moving towards WAP 10, quality of wireless channel 38 is likely to improve, and hence a more aggressive transmission bit-rate control (e.g., a transmission bit-rate control that provides for transmission of a higher number of bits for a given time duration) may be employed. If wireless communication device 36 is under macro-mobility and is moving away from WAP 10, a more conservative bit-rate control (e.g., a transmission bit-rate control that provides for transmission of a lower number of bits for a given time duration) may be employed. Under macro-mobility, wireless protocol selection instructions may also roam wireless communication device 36 to WAP 10 (or another nearby WAP) with higher wireless channel quality. If wireless communication device 36 is in the static state relative to WAP 10, the wireless protocol selection instructions may prevent consideration of roaming under the assumption that it is unlikely to result in discovery of a WAP with a higher wireless channel quality.
  • a more aggressive transmission bit-rate control e.g., a transmission bit-rate control that provides for transmission of a higher number of bits
  • wireless protocol selection instructions may similarly select an appropriate wireless protocol for wireless channel 38 based on whether wireless communication device 36 is in the static state relative to WAP 10, under environmental mobility, under micro-mobility, or under macro- mobility relative to WAP 10.
  • the selection of the appropriate wireless protocol during movement of wireless communication device 36 relative to WAP 10 may be specified in order of (e.g., from aggressive to conservative in order of transmission of a number of bits for a given time duration) the static state, the environmental mobility state, the micro-mobility state, and followed by the macro-mobility state.
  • wireless communication device 36 can be in the form of any suitable device that can be subject to multiple mobility states (e.g., static, environmental, macro-, and micro-mobility states).
  • suitable forms of wireless communication device 36 can include, for example, suitable smartphones, tablets, PCs, laptops, etc.
  • wireless communication device 36 includes a processor 44 and a machine-readable storage medium 46 that stores CSI feedback instructions.
  • processor 44 of wireless communication device 36 can include one or more aspects or functionality of processor 44 of WAP 10 described above.
  • machine-readable storage medium 46 of wireless communication device 36 can include one or more aspects or functionality of machine-readable storage medium 46 of WAP 10 described above.
  • Wireless communication device 36 can, for example, include an antenna 48 for wireless communication with WAP 10. It is appreciated that additional or alternative wireless technologies can be used for communication with WAP 10. It is further appreciated that antenna 40 of WAP and antenna 48 of WCD can be in the form of multiple antenna arrays or single antenna on each device.
  • Wireless communication device 36 includes CSI feedback instructions 50 which instruct wireless communication device 36 to provide CSI feedback to WAP 10 according to a CSI feedback polling period determined by WAP 10.
  • the CSI feedback can be packaged in the form of an 8-bit value to provide a measurement of wireless channel 38 between WAP 10 and wireless communication device 36. It is appreciated that CSI feedback can be determined by wireless communication device 36 and provided to WAP 10 using one or more other suitable techniques.

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

Abstract

La présente invention concerne une période de rétroaction d'informations d'état de canal qui peut, dans certains exemples, être déterminée en fonction d'un état de mobilité d'un dispositif de communication sans fil en communication sans fil avec un point d'accès sans fil. Un point d'accès sans fil peut avoir pour instruction de sonder sans fil le dispositif de communication sans fil concernant des informations d'état de canal en fonction de la période déterminée de rétroaction d'informations d'état de canal.
PCT/US2014/067009 2014-11-24 2014-11-24 Détermination de période de rétroaction d'informations d'état de canal en fonction d'un état de mobilité de dispositif de communication sans fil WO2016085440A1 (fr)

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