Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P17/00—Drugs for dermatological disorders
  • A61P17/02—Drugs for dermatological disorders for treating wounds, ulcers, burns, scars, keloids, or the like
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/12—Wireless traffic scheduling
  • H04W72/1263—Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows
  • H04W72/1268—Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows of uplink data flows
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L5/00—Arrangements affording multiple use of the transmission path
  • H04L5/003—Arrangements for allocating sub-channels of the transmission path
  • H04L5/0053—Allocation of signalling, i.e. of overhead other than pilot signals
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W28/00—Network traffic management; Network resource management
  • H04W28/02—Traffic management, e.g. flow control or congestion control
  • H04W28/06—Optimizing the usage of the radio link, e.g. header compression, information sizing, discarding information
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/20—Control channels or signalling for resource management
  • H04W72/23—Control channels or signalling for resource management in the downlink direction of a wireless link, i.e. towards a terminal
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W74/00—Wireless channel access
  • H04W74/002—Transmission of channel access control information

Definitions

• Certain aspects of the present disclosure generally relate to wireless communications, and more particularly, to methods and apparatus for multiple user uplink communication in a wireless network.
• communications networks are used to exchange messages among several interacting spatially-separated devices.
• Networks may be classified according to geographic scope, which could be, for example, a metropolitan area, a local area, or a personal area. Such networks may be designated respectively as a wide area network (WAN), metropolitan area network (MAN), local area network (LAN), or personal area network (PAN).
• WAN wide area network
• MAN metropolitan area network
• LAN local area network
• PAN personal area network
• Networks also differ according to the switching/routing technique used to interconnect the various network nodes and devices (e.g., circuit switching vs. packet switching), the type of physical media employed for transmission (e.g., wired vs. wireless), and the set of communication protocols used (e.g., Internet protocol suite, SONET (Synchronous Optical Networking), Ethernet, etc.).
• SONET Synchronous Optical Networking
• Wireless networks are often preferred when the network elements are mobile and thus have dynamic connectivity needs, or if the network architecture is formed in an ad hoc, rather than fixed, topology.
• Wireless networks employ intangible physical media in an unguided propagation mode using electromagnetic waves in the radio, microwave, infra-red, optical, etc. frequency bands. Wireless networks advantageously facilitate user mobility and rapid field deployment when compared to fixed wired networks.
• One aspect of the disclosure provides a method for wireless communication.
• the method comprises receiving, at a user terminal, a trigger frame from an access point indicating a target transmission duration for transmission of a physical layer (PHY) service data unit (PSDU) to the access point.
• the method further comprises generating an aggregated medium access control (MAC) packet data unit (A-MPDU) frame comprising at least one A-MPDU subframe, the A-MPDU frame having a first length.
• the method further comprises determining whether an additional A-MPDU subframe having a second length may be added to the A-MPDU frame based at least in part on the first length, the second length, and the target transmission duration.
• MAC medium access control
• the method further comprises including one or more padding subframes in the A-MPDU frame based at least in part on a comparison between the first length and the target transmission duration.
• the method further comprises generating the PSDU, the PSDU including the A-MPDU frame.
• the method further comprises transmitting the generated PSDU from the user terminal over the target transmission duration.
• Another aspect of the disclosure provides a user terminal for wireless communication.
• the user terminal comprises a receiver configured to receive a trigger frame from an access point indicating a target transmission duration for transmission of a physical layer (PHY) service data unit (PSDU) to the access point.
• the user terminal further comprises a processor configured to generate an aggregated medium access control (MAC) packet data unit (A- MPDU) frame comprising at least one A-MPDU subframe, the A-MPDU frame having a first length, determine whether an additional A-MPDU subframe having a second length may be added to the A-MPDU frame based at least in part on the first length, the second length, and the target transmission duration, and include one or more padding subframes in the A-MPDU frame based at least in part on a comparison between the first length and the target transmission duration.
• the user terminal further comprises a transmitter configured to transmit the generated PSDU over the target transmission duration.
• Another aspect of the disclosure provides a user terminal for wireless communication.
• the user terminal comprises means for receiving a trigger frame from an access point indicating a target transmission duration for transmission of a physical layer (PHY) service data unit (PSDU) to the access point.
• the user terminal further comprises means for generating an aggregated medium access control (MAC) packet data unit (A-MPDU) frame comprising at least one A-MPDU subframe, the A-MPDU frame having a first length.
• the user terminal further comprises means for determining whether an additional A-MPDU subframe having a second length may be added to the A-MPDU frame based at least in part on the first length, the second length, and the target transmission duration.
• MAC medium access control
• the user terminal further comprises means for including one or more padding subframes in the A-MPDU frame based at least in part on a comparison between the first length and the target transmission duration.
• the user terminal further comprises means for generating the PSDU, the PSDU including the A-MPDU frame.
• the user terminal further comprises means for transmitting the generated PSDU over the target transmission duration.
• Another aspect of the disclosure provides a non-transitory computer readable medium comprising instructions that, when executed, perform a method of communication.
• the method comprises receiving, at a user terminal, a trigger frame from an access point indicating a target transmission duration for transmission of a physical layer (PHY) service data unit (PSDU) to the access point.
• PHY physical layer
• PSDU service data unit
• the method further comprises generating an aggregated medium access control (MAC) packet data unit (A-MPDU) frame comprising at least one A-MPDU subframe, the A-MPDU frame having a first length.
• the method further comprises determining whether an additional A-MPDU subframe having a second length may be added to the A-MPDU frame based at least in part on the first length, the second length, and the target transmission duration.
• MAC medium access control
• the method further comprises including one or more padding subframes in the A-MPDU frame based at least in part on a comparison between the first length and the target transmission duration.
• the method further comprises generating the PSDU, the PSDU including the A-MPDU frame.
• the method further comprises transmitting the generated PSDU from the user terminal over the target transmission duration.
• FIG. 1 illustrates a multiple-access multiple-input multiple-output system with access points and user terminals.
• FIG. 2 illustrates a block diagram of the access point 110 and two user terminals
• FIG. 3 illustrates various components that may be utilized in a wireless device that may be employed within a wireless communication system.
• FIG. 4 shows a time diagram of an example frame exchange of an uplink multi-user multiple-input multiple-output communication.
• FIG. 5 shows a time sequence diagram of another example frame exchange of an uplink multi-user multiple-input multiple-output communication.
• FIG. 6 shows a time sequence diagram of another example frame exchange of an uplink multi-user multiple-input multiple-output communication.
• FIG. 7 shows a time sequence diagram of another example frame exchange of an uplink multi-user multiple-input multiple-output communication.
• FIG. 8 shows a time sequence diagram of uplink multi-user multiple-input multiple- output communication.
• FIG. 9 shows a diagram of a request to transmit frame.
• FIG. 10 shows a diagram of a clear to transmit frame.
• FIG. 11 shows a diagram of another embodiment of a clear to transmit frame.
• FIG. 12 shows a diagram of another embodiment of a clear to transmit frame.
• FIG. 13 shows a diagram of another embodiment of a clear to transmit frame.
• FIG. 14 is a time sequence diagram that shows a user terminal fragmenting its data for transmission to fit a target transmission duration for an uplink multi-user multiple-input multiple-output transmission during a transmission opportunity.
• FIG. 15 is a time sequence diagram that shows a user terminal decreasing its transmission data rate to fit a target transmission duration for an uplink multi-user multiple- input multiple-output transmission during a transmission opportunity.
• FIG. 16 is a time sequence diagram that shows a user terminal increasing its transmission data rate to fit a target transmission duration for an uplink multi-user multiple- input multiple-output transmission during a transmission opportunity.
• FIG. 17 is a time sequence diagram that shows a user terminal decreasing its level of aggregation to fit a target transmission duration for an uplink multi-user multiple-input multiple-output transmission during a transmission opportunity.
• FIG. 18 is a time sequence diagram that shows a user terminal increasing its level of aggregation to fit a target transmission duration for an uplink multi-user multiple-input multiple-output transmission during a transmission opportunity.
• FIG. 19 is a time sequence diagram that shows a user terminal adding fill data 1908 to fit a target transmission duration for an uplink multi-user multiple-input multiple-output transmission during a transmission opportunity.
• FIG. 20 is a time sequence diagram that shows a user terminal decreasing its transmission data rate, decreasing its level of aggregation, and adding fill data to fit a target transmission duration for an uplink multi-user multiple-input multiple-output transmission during a transmission opportunity.
• FIG. 21 is a time sequence diagram that shows a user terminal increasing its transmission data rate, increasing its level of aggregation, and adding fill data to fit a target transmission duration for an uplink multi-user multiple-input multiple-output transmission during a transmission opportunity.
• FIG. 22 is a time sequence diagram that shows user terminals concurrently transmitting data during a transmission opportunity for a duration that fits a target transmission duration.
• FIG. 23 is another time sequence diagram that shows user terminals utilizing fill subframes to fill a target transmission duration.
• FIG. 24 is a flow chart of a method for selecting data for transmission or operating parameters such that a duration of an uplink multi-user multiple-input multiple-output transmission fills a target transmission duration.
• FIG. 25 is a flowchart illustrating a method for wireless communication involving the generation of an A-MPDU for transmission.
• FIG. 26 is another flowchart illustrating a method for wireless communication including multiple alternative embodiments of generating padding.
• Wireless network technologies may include various types of wireless local area networks (WLANs).
• WLAN wireless local area networks
• a WLAN may be used to interconnect nearby devices together, employing widely used networking protocols.
• the various aspects described herein may apply to any communication standard, such as Wi-Fi or, more generally, any member of the IEEE 802.11 family of wireless protocols.
• wireless signals may be transmitted according to a high-efficiency
• 802.11 protocol using orthogonal frequency-division multiplexing (OFDM), direct-sequence spread spectrum (DSSS) communications, a combination of OFDM and DSSS communications, or other schemes.
• OFDM orthogonal frequency-division multiplexing
• DSSS direct-sequence spread spectrum
• Implementations of the high-efficiency 802.11 protocol may be used for Internet access, sensors, metering, smart grid networks, or other wireless applications.
• aspects of certain devices implementing this particular wireless protocol may consume less power than devices implementing other wireless protocols, may be used to transmit wireless signals across short distances, and/or may be able to transmit signals less likely to be blocked by objects, such as humans.
• a WLAN includes various devices which are the components that access the wireless network.
• access points APs
• clients also referred to as stations, or "STAs”
• an AP serves as a hub or base station for the WLAN and an STA serves as a user of the WLAN.
• a STA may be a laptop computer, a personal digital assistant (PDA), a mobile phone, etc.
• PDA personal digital assistant
• an STA connects to an AP via a Wi-Fi (e.g., IEEE 802.11 protocol such as 802.11 ah) compliant wireless link to obtain general connectivity to the Internet or to other wide area networks.
• Wi-Fi e.g., IEEE 802.11 protocol such as 802.11 ah
• an STA may also be used as an AP.
• the techniques described herein may be used for various broadband wireless communication systems, including communication systems that are based on an orthogonal multiplexing scheme.
• Examples of such communication systems include Spatial Division Multiple Access (SDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single-Carrier Frequency Division Multiple Access (SC-FDMA) systems, and so forth.
• SDMA Spatial Division Multiple Access
• TDMA Time Division Multiple Access
• OFDMA Orthogonal Frequency Division Multiple Access
• SC-FDMA Single-Carrier Frequency Division Multiple Access
• An SDMA system may utilize sufficiently different directions to simultaneously transmit data belonging to multiple user terminals.
• a TDMA system may allow multiple user terminals to share the same frequency channel by dividing the transmission signal into different time slots, each time slot being assigned to different user terminal.
• a TDMA system may implement GSM or some other standards known in the art.
• An OFDMA system utilizes orthogonal frequency division multiplexing (OFDM), which is a modulation technique that partitions the overall system bandwidth into multiple orthogonal sub-carriers. These sub-carriers may also be called tones, bins, etc. With OFDM, each sub-carrier may be independently modulated with data.
• An OFDM system may implement IEEE 802.11 or some other standards known in the art.
• An SC-FDMA system may utilize interleaved FDMA (IFDMA) to transmit on sub-carriers that are distributed across the system bandwidth, localized FDMA (LFDMA) to transmit on a block of adjacent sub-carriers, or enhanced FDMA (EFDMA) to transmit on multiple blocks of adjacent sub- carriers.
• IFDMA interleaved FDMA
• LFDMA localized FDMA
• EFDMA enhanced FDMA
• modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDMA.
• a SC-FDMA system may implement 3GP
• a wireless node implemented in accordance with the teachings herein may comprise an access point or an access terminal.
• An access point may comprise, be implemented as, or known as a NodeB,
• Radio Network Controller eNodeB
• BSC Base Station Controller
• BTS Base Transceiver Station
• BS Base Station
• TF Transceiver Function
• RNC Radio Network Controller
• BSC Base Station Controller
• TF Transceiver Function
• BSS Basic Service Set
• ESS Extended Service Set
• RBS Radio Base Station
• a station “STA” may also comprise, be implemented as, or known as a user terminal, an access terminal ("AT”), a subscriber station, a subscriber unit, a mobile station, a remote station, a remote terminal, a user agent, a user device, user equipment, or some other terminology.
• an access terminal may comprise a cellular telephone, a cordless telephone, a Session Initiation Protocol ("SIP”) phone, a wireless local loop (“WLL”) station, a personal digital assistant (“PDA”), a handheld device having wireless connection capability, or some other suitable processing device connected to a wireless modem.
• SIP Session Initiation Protocol
• WLL wireless local loop
• PDA personal digital assistant
• a phone e.g., a cellular phone or smartphone
• a computer e.g., a laptop
• a portable communication device e.g., a headset
• a portable computing device e.g., a personal data assistant
• an entertainment device e.g., a music or video device, or a satellite radio
• gaming device or system e.g., a gaming console, a global positioning system device, or any other suitable device that is configured to communicate via a wireless medium.
• FIG. 1 is a diagram that illustrates a multiple-access multiple-input multiple-output
• MIMO multiple access point
• An access point is generally a fixed station that communicates with the user terminals and may also be referred to as a base station or using some other terminology.
• a user terminal or STA may be fixed or mobile and may also be referred to as a mobile station or a wireless device, or using some other terminology.
• the access point 110 may communicate with one or more user terminals 120 at any given moment on the downlink and uplink.
• the downlink i.e., forward link
• the uplink i.e., reverse link
• a user terminal may also communicate peer-to-peer with another user terminal.
• a system controller 130 couples to and provides coordination and control for the access points.
• the user terminals 120 may also include some user terminals that do not support SDMA.
• the AP 110 may be configured to communicate with both SDMA and non- SDMA user terminals. This approach may conveniently allow older versions of user terminals (“legacy" stations) that do not support SDMA to remain deployed in an enterprise, extending their useful lifetime, while allowing newer SDMA user terminals to be introduced as deemed appropriate.
• the system 100 employs multiple transmit and multiple receive antennas for data transmission on the downlink and uplink.
• the access point 110 is equipped with N ap antennas and represents the multiple-input (MI) for downlink transmissions and the multiple- output (MO) for uplink transmissions.
• a set of K selected user terminals 120 collectively represents the multiple-output for downlink transmissions and the multiple-input for uplink transmissions.
• MI multiple-input
• MO multiple-output
• K may be greater than N ap if the data symbol streams can be multiplexed using TDMA technique, different code channels with CDMA, disjoint sets of sub-bands with OFDM, and so on.
• Each selected user terminal may transmit user-specific data to and/or receive user- specific data from the access point.
• each selected user terminal may be equipped with one or multiple antennas (i.e., N ui ⁇ 1).
• the K selected user terminals can have the same number of antennas, or one or more user terminals may have a different number of antennas.
• the SDMA system 100 may be a time division duplex (TDD) system or a frequency division duplex (FDD) system.
• TDD time division duplex
• FDD frequency division duplex
• the MFMO system 100 may also utilize a single carrier or multiple carriers for transmission.
• Each user terminal may be equipped with a single antenna (e.g., in order to keep costs down) or multiple antennas (e.g., where the additional cost can be supported).
• the system 100 may also be a TDMA system if the user terminals 120 share the same frequency channel by dividing transmission/reception into different time slots, where each time slot may be assigned to a different user terminal 120.
• FIG. 2 illustrates a block diagram of the access point 110 and two user terminals
• the access point 110 is equipped with N t antennas 224a through 224ap.
• the user terminal 120m is equipped with N ut;m antennas 252 ⁇ through 252 mu
• the user terminal 120x is equipped with N ut;X antennas 252 xa through 252 ⁇ .
• the access point 110 is a transmitting entity for the downlink and a receiving entity for the uplink.
• the user terminal 120 is a transmitting entity for the uplink and a receiving entity for the downlink.
• a "transmitting entity” is an independently operated apparatus or device capable of transmitting data via a wireless channel
• a “receiving entity” is an independently operated apparatus or device capable of receiving data via a wireless channel.
• N up user terminals are selected for simultaneous transmission on the uplink
• N dn user terminals are selected for simultaneous transmission on the downlink.
• N U p may or may not be equal to ⁇
• N up and N dn may be static values or may change for each scheduling interval. Beam-steering or some other spatial processing technique may be used at the access point 110 and/or the user terminal 120.
• a TX data processor 288 receives traffic data from a data source 286 and control data from a controller 280.
• the TX data processor 288 processes (e.g., encodes, interleaves, and modulates) the traffic data for the user terminal based on the coding and modulation schemes associated with the rate selected for the user terminal and provides a data symbol stream.
• a TX spatial processor 290 performs spatial processing on the data symbol stream and provides N ut,m transmit symbol streams for the N ut,m antennas.
• Each transmitter unit (“TMTR") 254 receives and processes (e.g., converts to analog, amplifies, filters, and frequency upconverts) a respective transmit symbol stream to generate an uplink signal.
• N ut,m transmitter units 254 provide N ut,m uplink signals for transmission from N ut,m antennas 252, for example to transmit to the access point 110.
• N U p user terminals may be scheduled for simultaneous transmission on the uplink.
• Each of these user terminals may perform spatial processing on its respective data symbol stream and transmit its respective set of transmit symbol streams on the uplink to the access point 110.
• N up antennas 224a through 224 ap receive the uplink signals from all N up user terminals transmitting on the uplink.
• Each antenna 224 provides a received signal to a respective receiver unit ("RCVR") 222.
• Each receiver unit 222 performs processing complementary to that performed by transmitter unit 254 and provides a received symbol stream.
• An RX spatial processor 240 performs receiver spatial processing on the N up received symbol streams from N up receiver units 222 and provides N up recovered uplink data symbol streams.
• the receiver spatial processing may be performed in accordance with the channel correlation matrix inversion (CCMI), minimum mean square error (MMSE), soft interference cancellation (SIC), or some other technique.
• Each recovered uplink data symbol stream is an estimate of a data symbol stream transmitted by a respective user terminal.
• An RX data processor 242 processes (e.g., demodulates, deinterleaves, and decodes) each recovered uplink data symbol stream in accordance with the rate used for that stream to obtain decoded data.
• the decoded data for each user terminal may be provided to a data sink 244 for storage and/or a controller 230 for further processing.
• a TX data processor 210 receives traffic data from a data source 208 for Ndn user terminals scheduled for downlink transmission, control data from a controller 230, and possibly other data from a scheduler 234.
• the various types of data may be sent on different transport channels.
• TX data processor 210 processes (e.g., encodes, interleaves, and modulates) the traffic data for each user terminal based on the rate selected for that user terminal.
• the TX data processor 210 provides Ndn downlink data symbol streams for the Ndn user terminals.
• a TX spatial processor 220 performs spatial processing (such as a precoding or beamforming) on the Ndn downlink data symbol streams, and provides N up transmit symbol streams for the N up antennas.
• Each transmitter unit 222 receives and processes a respective transmit symbol stream to generate a downlink signal.
• N Up transmitter units 222 may provide N up downlink signals for transmission from N up antennas 224, for example to transmit to the user terminals 120.
• N utj m antennas 252 receive the N up downlink signals from the access point 110.
• Each receiver unit 254 processes a received signal from an associated antenna 252 and provides a received symbol stream.
• An RX spatial processor 260 performs receiver spatial processing on N ut;m received symbol streams from N ut;m receiver units 254 and provides a recovered downlink data symbol stream for the user terminal 120.
• the receiver spatial processing may be performed in accordance with the CCMI, MMSE, or some other technique.
• An RX data processor 270 processes (e.g., demodulates, deinterleaves and decodes) the recovered downlink data symbol stream to obtain decoded data for the user terminal.
• a channel estimator 278 estimates the downlink channel response and provides downlink channel estimates, which may include channel gain estimates, SNR estimates, noise variance and so on.
• a channel estimator 228 estimates the uplink channel response and provides uplink channel estimates.
• Controller 280 for each user terminal typically derives the spatial filter matrix for the user terminal based on the downlink channel response matrix Hd n,m for that user terminal.
• Controller 230 derives the spatial filter matrix for the access point based on the effective uplink channel response matrix H uP; eff.
• the controller 280 for each user terminal may send feedback information (e.g., the downlink and/or uplink eigenvectors, eigenvalues, SNR estimates, and so on) to the access point 110.
• the controllers 230 and 280 may also control the operation of various processing units at the access point 110 and user terminal 120, respectively.
• FIG. 3 illustrates various components that may be utilized in a wireless device 302 that may be employed within the wireless communication system 100.
• the wireless device 302 is an example of a device that may be configured to implement the various methods described herein.
• the wireless device 302 may implement an access point 110 or a user terminal 120.
• the wireless device 302 may include a processor 304 which controls operation of the wireless device 302.
• the processor 304 may also be referred to as a central processing unit (CPU).
• Memory 306 which may include both read-only memory (ROM) and random access memory (RAM), provides instructions and data to the processor 304.
• a portion of the memory 306 may also include non-volatile random access memory (NVRAM).
• the processor 304 may perform logical and arithmetic operations based on program instructions stored within the memory 306.
• the instructions in the memory 306 may be executable to implement the methods described herein.
• the processor 304 may comprise or be a component of a processing system implemented with one or more processors.
• the one or more processors may be implemented with any combination of general-purpose microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate array (FPGAs), programmable logic devices (PLDs), controllers, state machines, gated logic, discrete hardware components, dedicated hardware finite state machines, or any other suitable entities that can perform calculations or other manipulations of information.
• the processing system may also include machine-readable media for storing software.
• Software shall be construed broadly to mean any type of instructions, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Instructions may include code (e.g., in source code format, binary code format, executable code format, or any other suitable format of code). The instructions, when executed by the one or more processors, cause the processing system to perform the various functions described herein.
• the wireless device 302 may also include a housing 308 that may include a transmitter 310 and a receiver 312 to allow transmission and reception of data between the wireless device 302 and a remote location.
• the transmitter 310 and receiver 312 may be combined into a transceiver 314.
• a single or a plurality of transceiver antennas 316 may be attached to the housing 308 and electrically coupled to the transceiver 314.
• the wireless device 302 may also include (not shown) multiple transmitters, multiple receivers, and multiple transceivers.
• the wireless device 302 may also include a signal detector 318 that may be used in an effort to detect and quantify the level of signals received by the transceiver 314.
• the signal detector 318 may detect such signals as total energy, energy per subcarrier per symbol, power spectral density and other signals.
• the wireless device 302 may also include a digital signal processor (DSP) 320 for use in processing signals.
• DSP digital signal processor
• the various components of the wireless device 302 may be coupled together by a bus system 322, which may include a power bus, a control signal bus, and a status signal bus in addition to a data bus.
• a bus system 322 may include a power bus, a control signal bus, and a status signal bus in addition to a data bus.
• the UL signal may be transmitted in a multi-user MIMO (MU-MIMO) system.
• the UL signal may be transmitted in a multi-user FDMA (MU-FDMA) or similar FDMA system.
• FIGs. 4-8 illustrate uplink MU-MIMO (UL-MU-MFMO) transmissions 410A and 410B that would apply equally to UL-OFDMA transmissions.
• UL-MU-MIMO or UL-OFDMA transmissions can be sent simultaneously from multiple STAs to an AP and may create efficiencies in wireless communication.
• FIG. 4 is a time sequence diagram 400 showing an example of an UL-MU-MIMO protocol 400 that may be used for UL communications.
• the AP 110 may transmit a clear to transmit (CTX) message 402 to the user terminals 120 indicating which user terminals 120 may participate in the UL-MU-MFMO scheme, such that a particular UT 120 knows to start an UL-MU-MFMO transmission.
• CTX message 402 may be transmitted in a payload portion of a physical layer convergence protocol (PLCP) protocol data units (PPDUs).
• PLCP physical layer convergence protocol
• PPDUs protocol data units
• a user terminal 120 may transmit the UL-MU-MFMO transmission 410.
• STA 120A and STA 120B transmit UL-MU-MIMO transmissions 410A and 410B, respectively, containing physical layer convergence protocol (PLCP) protocol data units (PPDUs).
• PLCP physical layer convergence protocol
• PPDUs protocol data units
• the AP 110 may transmit block acknowledgments (BAs) 470 to the user terminals 120A and 120B.
• BAs block acknowledgments
• Not all APs 110 or user terminals 120 may support UL-MU-MFMO or UL-OFDMA operation.
• a capability indication from a user terminal 120 may be indicated in a high efficiency wireless (HEW) capability element that is included in an association request or probe request and may include a bit indicating capability, the maximum number of spatial streams a user terminal 120 can use in a UL-MU- MFMO transmission, the frequencies a user terminal 120 can use in a UL-OFDMA transmission, the minimum and maximum power and granularity in the power backoff, and the minimum and maximum time adjustment a user terminal 120 can perform.
• HAW high efficiency wireless
• a capability indication from an AP 110 may be indicated in a HEW capability element that is included in an association response, beacon or probe response and may include a bit indicating capability, the maximum number of spatial streams a single user terminal 120 can use in a UL-MU-MFMO transmission, the frequencies a single user terminal 120 can use in a UL-OFDMA transmission, the required power control granularity, and the required minimum and maximum time adjustment a user terminal 120 should be able to perform.
• capable user terminals 120 may request to a capable AP to be part of the UL-MU-MIMO (or UL-OFDMA) protocol.
• the request may be included in a management frame, a request to send (RTS) message, a quality of service (QoS) frame, a power save (PS) poll, or an RTX frame.
• RTS request to send
• QoS quality of service
• PS power save
• an AP 110 may respond by granting the user terminal 120 the use of the UL-MU-MIMO feature or the AP 110 may deny the user terminal's request.
• the AP 110 may grant the use of the UL-MU-MIMO and the user terminal 120 may expect a CTX message 402 at a variety of times.
• the user terminal 120 may be subject to following a certain operation mode.
• the user terminal 120 and the AP 110 may support multiple operation modes and the AP 110 may indicate to the user terminal 120 which mode to use in a HEW capability element, a management frame, or in an operation element.
• a user terminal 120 may change the operation mode and parameters dynamically during operation by sending a different operating element to the AP 110.
• the AP 110 may switch the operation mode dynamically during operation by sending an updated operating element or a management frame to the user terminal 120, or by sending the updated operating element or the updated management frame in a beacon.
• the operation mode may be determined by the AP 110 in the setup phase and may be determined per user terminal 120 or for a group of user terminals 120.
• the operation mode may be specified per traffic identifier (TID).
• a user terminal 120 may receive a CTX message from an AP 110 and immediately send a response to the AP 110.
• the response may be in the form of a clear to send (CTS) message or another type of message.
• CTS clear to send
• the requirement to send the CTS message may be indicated in the CTX message or the requirement may be indicated in the setup phase of the communication between the AP 110 and the user terminal 120.
• FIG. 5 is a time sequence diagram 500 that, in conjunction with FIG. 1, shows an example of an operation mode of UL-MU-MTMO transmissions between an AP 110 and user terminals 120A and 120B.
• UT 120A may transmit a CTS message 408A
• UT 120B may transmit a CTS message 408B in response to receiving the CTX message 402 from the AP 110.
• the modulation and coding scheme (MCS) of the CTS message 408A and the CTS message 408B may be based on the MCS of the CTX message 402.
• the CTS message 408A and the CTS message 408B contain the same amount of bits and the same scrambling sequence so that they may be transmitted to the AP 110 at the same time.
• a duration field of the CTS messages 408A and 408B may be based on a duration field in the CTX by removing the time for the CTX PPDU.
• the user terminal 120 A may send an UL-MU-MIMO transmission 41 OA to the AP 110 according to the CTX message 402 and the user terminal 120B may also send an UL-MU-MFMO transmission 410B to the AP 110 according to the CTX message 402.
• the AP 110 may then send an acknowledgment (ACK) message 475 to the user terminals 120A and 120B.
• ACK acknowledgment
• the ACK message 475 may include serial ACK messages sent to each user terminal 120 or the ACK message 475 may include BAs. In some aspects the ACKs 475 may be polled.
• the embodiment of FIG. 5 may improve transmission efficiency by providing concurrent transmission of CTS messages 408 from multiple user terminals 120 to an AP 110, compared to sequential transmission, thereby saving time and reducing the possibility of interference.
• FIG. 6 is a time sequence diagram 600 that, in conjunction with FIG. 1, shows an example of an operation mode of UL-MU-MFMO transmissions.
• user terminals 120A and 120B may receive a CTX message 402 from an AP 110.
• the CTX message 402 may indicate a time (T) 406 after the end of the PPDU carrying the CTX message 402 for the user terminals 120 A and 120B to transmit UL-MU-MIMO transmissions.
• the T 406 may be a short interframe space (SIFS), a point interframe space (PIFS), or another time.
• the T may include time offsets as indicated by the AP 110 in the CTX message 402 or via a management frame.
• the SIFS and PIFS time may be fixed in a standard or may be indicated by the AP 110 in the CTX message 402 or in a management frame.
• the T 406 may improve synchronization between the AP 110 and the user terminals 120 A and 120B and it may allow the user terminals 120 A and 120B sufficient time to process the CTX message 402, or other messages, before sending their UL-MU-MIMO transmissions.
• a user terminal 120 may have data to upload to the AP 110 but the user terminal 120 may not have received a CTX message 402 or another message indicating that the user terminal 120 may start an UL-MU-MIMO transmission.
• the user terminals 120 may not transmit data outside of an UL-MU-MIMO transmission opportunity (TXOP) (e.g., after CTX message).
• TXOP UL-MU-MIMO transmission opportunity
• user terminals 120 may transmit frames to the AP 110 to initialize a UL-MU-MFMO transmission and may then transmit during the UL-MU-MIMO TXOP, if for example, they are instructed to do so in a CTX message.
• the frame to initialize a UL-MU-MIMO transmission may be a request to transmit (RTX), a frame specifically designed for this purpose (an example of a RTX frame structure is described more fully below with reference to FIG. 9).
• RTX frames may be the only frame type a user terminal 120 may use to initiate a UL-MU-MIMO TXOP.
• the user terminal 120 may not transmit outside of an UL-MU-MIMO TXOP other than by sending an RTX.
• MIMO transmission may be any frame which indicates to an AP 110 that a user terminal 120 has data to send.
• the AP 110 and the user terminal 120 may determine during setup that such frames may indicate an UL-MU-MIMO TXOP request.
• the following may be used to indicate that a user terminal 120 has data to send and is requesting an UL- MU-MFMO TXOP: an RTS, a data frame or QoS Null set to indicate more data, or a PS poll.
• the data frame or QoS null frame may have bits 8-15 of the QoS control frame set to indicate more data.
• the user terminal 120 may not transmit outside an UL-MU-MIMO TXOP other than by sending frames to trigger this TXOP, where this frame may be an RTS, PS poll, or QOS null.
• the user terminal 120 may send single user uplink data as usual, and may indicate a request for an UL-MU-MFMO TXOP by setting bits in the QoS control frame of its data packet.
• FIG. 7 is a time sequence diagram 700 showing, in conjunction with FIG. 1, an example of UL-MU-MFMO communications including a user terminal 120A sending an RTX message 701 to the AP 110 to request and initialize an UL-MU-MIMO transmission.
• the RTX message 701 sent to the AP 110 by the user terminal 120A includes information regarding UL-MU-MIMO transmissions.
• an RTX message may be sent by the user terminal 120B. As shown in FIG.
• the AP 110 may respond to the RTX message 701 with a CTX message 402 granting an UL-MU-MIMO TXOP 730 to the user terminal 120A for sending a UL-MU-MIMO transmission 410A immediately following the CTX message 402.
• the CTX message 402 may also grant the UL-MU-MIMO TXOP 730 to the user terminal 120B for concurrently sending a UL-MU- MIMO transmission 410B with the UL-MU-MIMO transmission 41 OA, both transmissions 41 OA and 410B immediately following the CTX message 402.
• the user terminal 120A may send the UL-MU-MIMO transmission 410A for a duration indicated by the AP 110 in the CTX 402 and the user terminal 120B may also send the UL-MU-MIMO transmission 410B for the same duration.
• the AP 110 may respond with a CTS that grants a single-user (SU)
• the AP 110 may respond with a frame (e.g., ACK or CTX with a special indication) that acknowledges the reception of the RTX 701 but does not grant an immediate UL-MU-MIMO TXOP.
• the AP 110 may respond with a frame that acknowledges the reception of the RTX 701, does not grant an immediate UL-MU- MIMO TXOP, but grants a delayed UL-MU-MFMO TXOP and may identify the time that the TXOP is granted.
• the AP 110 may send a CTX message 402 to start the UL-MU-MIMO at the granted time.
• the AP 110 may respond to the RTX 701 with an ACK or other response signal which does not grant the user terminal 120 an UL-MU-MIMO transmission but indicates that the user terminal 120 shall wait for a time (T) before attempting another transmission (e.g., sending another RTX).
• the time (T) may be indicated by the AP 110 in the setup phase or in the response signal.
• an AP 110 and a user terminal 120 may agree on a time which the user terminal 120 may transmit a RTX 701, RTS, PS-poll, or any other request for a UL-MU- ⁇ TXOP.
• user terminals 120 may transmit requests for UL-MU-
• the contention parameters for user terminals 120 using UL-MU-MIMO are set to a different value than for other user terminals that are not using the UL-MU-MIMO feature.
• the AP 110 may indicate the value of the contention parameters in a beacon, in an association response or through a management frame.
• the AP 110 may provide a delay timer that prevents a user terminal 120 from transmitting for a certain amount of time after each successful UL-MU-MFMO TXOP or after each RTX, RTS, PS-poll, or QoS null frame. The timer may be restarted after each successful UL-MU-MTMO TXOP.
• the AP 110 may indicate the delay timer to user terminals 120 in the setup phase or the delay timer may be different for each user terminal 120. In another aspect, the AP 110 may indicate the delay timer in the CTX message 402 or the delay timer may be dependent on the order of the user terminals 120 in the CTX message 402, and may be different for each terminal.
• the AP 110 may indicate a time interval during which the user terminals 120 are allowed to transmit a UL-MU-MIMO transmission.
• the AP 110 indicates a time interval to the user terminals 120 during which the user terminals are allowed to send a RTX or RTS or other request to the AP 110 to ask for an UL-MU- MIMO transmission.
• the user terminals 120 may use regular contention protocol.
• the user terminals may not initiate a UL-MU-MFMO transmission during the time interval but the AP 110 may send a CTX or other message to the user terminals to initiate the UL-MU-MIMO transmission.
• a user terminal 120 enabled for UL-MU-MIMO may indicate to an AP 110 that it requests an UL-MU-MIMO TXOP because it has data pending for UL.
• the user terminal 120 may send a RTS or a PS-poll to request a UL-MU- MIMO TXOP.
• the user terminal 120 may send any data frame, including a quality of service (QoS) null data frame, where the bits 8-15 of the QoS control field indicate a non-empty queue.
• QoS quality of service
• the user terminal 120 may determine during the setup phase which data frames (e.g., RTS, PS-poll, QoS null, etc.) will trigger a UL-MU-MIMO transmission when the bits 8-15 of the QoS control field indicate a nonempty queue.
• the RTS, PS-poll, or QoS null frames may include a 1 bit indication allowing or disallowing the AP 110 to respond with a CTX message 402.
• the QoS null frame may include TX power information and a per TID queue information.
• the TX power information and per TID queue information may be inserted in the two bytes of the sequence control and QoS controls fields in a QoS null frame and the modified QoS null frame may be sent to the AP 110 to request a UL-MU-MFMO TXOP.
• the user terminal 120 may send a RTX 701 to request a UL-MU-MIMO TXOP.
• an AP 110 may send a CTX message 402.
• the TXOP may return to the user terminals 120A and 120B which may decide on how to use the remaining TXOP.
• the TXOP may return to the AP 110 and the AP 110 may use the remaining TXOP for additional UL-MU-MIMO transmissions by sending another CTX message 402 to either UTs 120A and 120B or to other UTs.
• FIG. 8 is a message timing diagram 800 showing multi-user uplink communication.
• the message exchange shows communication of wireless messages between an AP 110 and three user terminals 120A-C.
• the message exchange may indicate that each of the user terminals 120A-C may transmit a request-to-transmit (RTX) message 802A-C to the AP 110.
• RTX request-to-transmit
• Each of the RTX messages 802 A-C may indicate that the transmitting user terminal 120A-C has data available to be transmitted to the AP 110.
• the AP 110 may respond with a message indicating that the AP 110 has received the each of the RTX messages 802 A-C from the user terminals 120A-C. As shown in FIG. 8, the AP 110 may transmit ACK messages 803 A-C in response to each RTX messages 802A-C. In some embodiments, the AP 110 may transmit a message (e.g., a CTX message) indicating that each of the RTX messages 802A-C has been received but that the AP 110 has not granted a transmission opportunity for the user terminals 120 A-C to uplink data.
• a message e.g., a CTX message
• the AP 110 may transmit a CTX message 804.
• the CTX message 804 is transmitted to at least the user terminals 120A-C.
• the CTX message 804 is a broadcast message.
• the CTX message 804 may indicate which user terminals are granted permission to transmit data to the AP 110 during a transmission opportunity.
• the CTX message 804 may also indicate a starting time of the transmission opportunity and a duration of the transmission opportunity. For example, the CTX message 804 may indicate that the user terminals 120A-C should set their network allocation vectors to be consistent with NAV 812.
• the three user terminals 120A-C transmit data 806A-C to the AP 110.
• the data 806A-C are transmitted at least partially concurrently during the transmission opportunity.
• the transmissions of data 806A-C may utilize uplink multi-user multiple input, multiple output transmissions (UL-MU-MFMO) or uplink frequency division multiple access (UL-OFDMA).
• UL-MU-MFMO uplink multi-user multiple input, multiple output transmissions
• UL-OFDMA uplink frequency division multiple access
• user terminals 120A-C may transmit padded data such that the transmissions of each user terminal transmitting during a transmission opportunity are of equal duration or approximately equal duration.
• the user terminal 120 A may transmit pad data 808 A, the user terminal 120C may not transmit pad data, and the user terminal 120C may transmit pad data 808C.
• the transmission of pad data ensures that the transmissions from each of the UTs 120A-C complete at approximately the same time. This may provide for a more equalized transmission power over the entire duration of the transmission, thereby optimizing AP 110 receiver efficiencies.
• the AP 110 may transmit acknowledgment messages 810A-C to each of the user terminals 120A-C.
• the acknowledgments messages 810A-C may be transmitted at least partially concurrently using either DL-MU-MIMO or DL-FDMA.
• FIG. 9 is a diagram of one embodiment of an RTX frame 900.
• the RTX frame 900 may include a frame control (FC) field 910, an optional duration field 915, a transmitter address/allocation identifier (TA/AID) field 920, a receiver address/basic service set identifier (RA/BSSID) field 925, a TID field 930, an estimated transmission (TX) time field 950, and a TX power field 970.
• the FC field 910 may indicate a control subtype or an extension subtype.
• the duration field 915 may indicate to any receiver of the RTX frame 900 to set the network allocation vector ( AV). In one aspect, the RTX frame 900 may not have a duration field 915.
• the TA/AID field 920 may indicate a source address, which may be an AID or a full MAC address.
• the RA/BSSID field 925 may indicate the RA or BSSID.
• the RTX frame 900 may not contain a RA/BSSID field 925.
• the TID field 930 may indicate an access category (AC) for which a user terminal has data.
• the estimated TX time field 950 may indicate a time requested for a UL-TXOP based on an amount of time required for a user terminal 120 to send all the data in its buffer at the current planned MCS.
• the TX power field 970 may indicate the power at which the RTX frame 900 is being transmitted and may be used by the AP 110 to estimate the link quality and adapt the power backoff indication in a CTX frame.
• an UL-MU-MIMO communication before an UL-MU-MIMO communication can take place, an
• the AP 110 may collect information from the user terminals 120 that are participating in the UL- MU-MTMO communication.
• the AP 110 may optimize the collection of information from the user terminals 120 by scheduling the UL transmissions from the user terminals 120.
• FIG. 10 is a diagram of an example of a CTX frame 1000 structure.
• the CTX frame 1000 is a control frame that includes a frame control (FC) field 1005, a duration field 1010, a receiver address field 1014, a transmitter address (TA) field 1015, a control (CTRL) field 1020, a PPDU duration field 1025, a UT info field 1030, and a frame check sequence (FCS) field 1080.
• the FC field 1005 indicates a control subtype or an extension subtype.
• the duration field 1010 indicates to any receiver of the CTX frame 1000 to set the network allocation vector (NAV).
• NAV network allocation vector
• the RA 1014 field identifies a group of UTs through a multicast MAC address.
• the TA field 1015 indicates the transmitter address or a BSSID.
• the CTRL field 1020 is a generic field that may include information regarding the format of the remaining portion of the frame (e.g., the number of UT info fields and the presence or absence of any subfields within a UT info field), indications for rate adaptation for the user terminals 120, indication of allowed TID, and indication that a CTS must be sent immediately following the CTX frame 1000.
• the CTRL field 1020 may also indicate if the CTX frame 1000 is being used for UL-MU-MIMO or for UL FDMA or both, indicating whether a Nss or Tone allocation field is present in the UT Info field 1030.
• the indication of whether the CTX is for UL-MU-MIMO or for UL FDMA can be based on the value of the subtype.
• UL-MU-MIMO and UL FDMA operations can be jointly performed by specifying to a UT both the spatial streams to be used and the channel to be used, in which case both fields are present in the CTX; in this case, the Nss indication is referred to a specific tone allocation.
• the PPDU duration 1025 field indicates the duration of the following UL-MU-MIMO PPDU that the user terminals 120 are allowed to send.
• the AP 110 may determine the duration of the following Mu- MIMO PPDU that the user terminals 120 are allowed to send based on estimated TX time fields received in at least one RTX message from the user terminals 120.
• the UT Info 1030 field contains information regarding a particular UT and may include a per-UT (per user terminal 120) set of information (see UT Info 1 1030 and UT Info N 1075).
• the UT Info 1030 field may include an AID or MAC address field 1032 which identifies a UT, a number of spatial streams field (Nss) 1034 field which indicates the number of spatial streams a UT may use (in an UL-MU-MIMO system), a Time Adjustment 1036 field which indicates a time that a UT should adjust its transmission compared to the reception of a trigger frame (the CTX in this case), a Power Adjustment 1038 field which indicates a power backoff a UT should take from a declared transmit power, a Tone Allocation 1040 field which indicates the tones or frequencies a UT may use (in a UL-OFDMA system), an Allowed TID 1042 field which indicates the allowable TID, an Allowed TX Mode 1044 field which indicates the allowed TX modes, and a MCS 1046 field which indicates the MCS the UT should use.
• Nss spatial streams field
• a user terminal 120 receiving a CTX with a Allowed TID 1042 indication may be allowed to transmit data only of that TID, data of the same or higher TID, data of the same or lower TID, any data, or only data of that TID first, then if no data is available, data of other TIDs.
• the FCS 1080 field indicates the carries an FCS value used for error detection of the CTX frame 1000.
• FIG. 1 1 is a diagram of another example of a CTX frame 1100 structure.
• the UT Info 1030 field does not contain the AID or MAC Address 1032 field and instead the CTX frame 1000 includes a group identifier (GID) 1026 field which identifies the UTs by a group identifier rather than an individual identifier.
• FIG. 12 is a diagram of another example of a CTX frame 1200 structure. In this embodiment and in conjunction with FIG. 11, the GID 1026 field is replaced with a RA 1014 field which identifies a group of UTs through a multicast MAC address.
• FIG. 13 is a diagram of an example of a CTX frame 1300 structure.
• the CTX frame 1300 is a management frame that includes a Management MAC Header 1305 field, a Body 1310 field, and a FCS 1380 field.
• the Body 1310 field includes an IE ID 1315 field which identifies an information element (IE), a LEN 1320 field which indicates the length of the CTX frame 1300, a CTRL 1325 field which includes the same information as the CTRL 1020 field, a PPDU Duration 1330 field which indicates the duration of the following UL-MU-MFMO PPDU that the user terminals 120 are allowed to send, a UT Info 1 1335 field and a MCS 1375 field which can indicate the MCS for all the UTs to use in the following UL-MU-MIMO transmission, or an MCS backoff for all the UTs to use in the following UL-MU-MFMO transmission.
• IE ID 1315 field which identifies an information element (IE)
• IE information element
• LEN 1320 field which indicates the length of the CTX frame 1300
• CTRL 1325 field which includes the same information as the CTRL 1020 field
• a PPDU Duration 1330 field which indicates the duration of the following UL-MU-MFMO
• the UT Info 1 1335 (along with UT Info N 1370) field represent a per UT field that includes AID 1340 field which identifies a UT, a number of spatial streams field (Nss) 1342 field which indicates the number of spatial streams a UT may use (in an UL-MU-MIMO system), a Time Adjustment 1344 field which indicates a time that a UT should adjust its transmission compared to the reception of a trigger frame (the CTX in this case), a Power Adjustment 1346 field which indicates a power backoff a UT should take from a declared transmit power, a Tone Allocation 1348 field which indicates the tones or frequencies a UT may use (in a UL-OFDMA system), an Allowed TID 1350 field which indicates the allowable TID, and a TX start time field 1352 which indicates a start time for the UT to transmit uplink data.
• AID 1340 field which identifies a UT
• Nss spatial streams field
• Nss
• the CTX frame 1000 or the CTX frame 1300 may be aggregated in an A-MPDU to provide time to a user terminal 120 for processing before transmitting the UL signals.
• padding or data may be added after the CTX to allow a user terminal 120 additional time to process the forthcoming packet.
• One benefit to padding a CTX frame may be to avoid possible contention issues for the UL signals from other user terminals 120, as compared to increasing the interframe space (IFS) as described above.
• IFS interframe space
• additional padding information elements IEs
• additional A-MPDU padding delimiters may be included.
• Padding delimiters may be end-of-frame (EOF) delimiters (e.g., 4 bytes) or other padding delimiters.
• the padding may be achieved by adding data, control or Management MPDPUs, as long as they do not require to be processed within the IFS response time.
• the MPDUs may include an indication indicating to the receiver that no immediate response is required and will not be required by any of the following MPDUs.
• the user terminals 120 may request to an AP 110 a minimum duration or padding for the CTX frame.
• the padding may be achieved by adding PHY OFDMA symbols, which may include undefined bits not carrying information, or may include bit sequences that carry information, as long as they do not need to be processed within the IFS time.
• an AP 110 may initiate a CTX transmission.
• an AP 110 may send a CTX message 402 in accordance with regular enhanced distribution channel access (EDCA) contention protocol.
• EDCA enhanced distribution channel access
• an AP 110 may send a CTX message 402 at scheduled times.
• the scheduled times may be indicated by the AP 110 to the user terminals 120 by using a restricted access window (RAW) indication in a beacon which indicates a time reserved for a group of user terminals 120 to access the medium, a target wake time (TWT) agreement with each user terminal 120 which indicates to multiple user terminals 120 to be awake at the same time to take part in a UL-MU-MIMO transmission, or information in other fields.
• RAW restricted access window
• TWT target wake time
• a user terminal 102 may be allowed to transmit any frame, or only a subset of frames (e.g., non-data frames). It may also be forbidden to transmit certain frames (e.g., it may be forbidden to transmit data frames).
• the user terminal 120 may also indicate that it is in sleep state.
• One advantage to scheduling a CTX is that multiple user terminals 120 may be indicated the same TWT or the same RAW time and may receive a transmission from an AP 110.
• the user terminals 120 may plan to transmit data and may send a message (e.g., an RTX) to the AP 110 requesting to transmit their data.
• a message (e.g., CTX message 402) from the AP 110 may indicate a target transmission duration for the UL-MU-MIMO transmissions 410 from user terminals 120 utilizing the UL- MU-MIMO feature.
• the target transmission duration may also be determined by the AP 110 and the user terminals 120 in the setup phase.
• the user terminal 120 may determine a planned transmission duration of the planned data for transmission that it has for transmission based on a number of bits in the planned data and the operating and transmission parameters of the user terminal 120 (e.g., level of aggregation and MCS). The user terminal 120 may determine whether the planned transmission duration of the data for transmission fits, exceeds, or falls shown of the target transmission duration. In some circumstances, the user terminal 120 may have planned data for transmission that, when transmitted, will have a planned transmission duration that fits (e.g., is equal to) the target transmission duration such that the user terminal 120 may transmit its data without modification. In other circumstances, the user terminal 120 may have planned data for transmission that, when transmitted, would have a planned transmission duration that exceeds the target transmission duration.
• a planned transmission duration of the planned data for transmission that it has for transmission based on a number of bits in the planned data and the operating and transmission parameters of the user terminal 120 (e.g., level of aggregation and MCS). The user terminal 120 may determine whether the planned transmission duration of the data for transmission fits
• the user terminal 120 may change the planned data or its operating and transmission parameters such that the planned transmission duration of the data is decreased to fit the target transmission duration.
• the user terminal 120 may have planned data for transmission that, when transmitted, would have a planned transmission duration that falls short of the target transmission duration. In such circumstances the user terminal 120 may change the planned data or its operating or transmission parameters such that the planned transmission duration of the data is increased to fit the target transmission duration.
• the AP 110 may restrict the parameters that the user terminals 120 may change.
• the AP 110 may indicate such restrictions in a trigger frame.
• the AP 110 may specify a target transmission duration for the user terminals 120 and the user terminals 120 may each determine their UL PPDU duration, data payload size, MCS, and amount of fill data.
• the AP 110 may specify a target transmission duration and a UL PPDU duration for the user terminals 120 and the user terminals 120 may each determine their data payload size, MCS, and amount of fill data.
• the AP 110 may specify a target transmission duration, UL PPDU duration, and MCS for the user terminals 120 and the user terminals 120 may each adjust their data payload size and amount of fill data.
• the user terminals 120 may send information to the AP 110 indicating their data payload size.
• the AP 110 may determine an amount of fill data for each user terminal 120 based on the data payload sizes of the user terminals 120 and the AP 110 may indicate an amount of fill data to use, a target transmission duration, a UL PPDU duration, and an MCS for each of the user terminals 120 in the trigger frame.
• each of the user terminals 120 may determine their data payload size.
• the AP 110 may indicate a target transmission duration, a UL PPDU duration, data payload size, MCS, and an amount of fill data for each of the user terminals 120.
• the AP 110 may indicate a level of data aggregation for each user terminal 120 to use as discussed further discussed below. Accordingly, the user terminals 120 may determine operating and transmission parameter adjustments which are not specified by the AP 1 10 in the trigger frame.
• FIGs. 14-22 show examples of changes that user terminals 120 may make to their data for transmission or their operating and transmission parameters in order to fit the target transmission duration.
• FIG. 14 is a time sequence diagram 1400 that shows a user terminal 120 fragmenting its planned data for transmission to fit a target transmission duration 1420 for a UL-MU- MIMO transmission during a transmission opportunity.
• the dashed arrows in FIG. 14 indicate that a duration of a first PPDU 141 OA as transmitted by the user terminal 120 remains the same as a planned transmission duration of a first portion of the data for transmission 1406A.
• an AP 110 may indicate the target transmission duration 1420 in a message granting a transmission opportunity (e.g., a CTX message) to the user terminal 120.
• a transmission opportunity e.g., a CTX message
• the user terminal 120 may have planned data for transmission 1406 that, when transmitted, has a planned transmission duration that exceeds the target transmission duration 1420.
• the user terminal 120 may change the planned data 1406 to fit the target transmission duration 1420 by fragmenting the planned data 1406 into a first portion of data 1406 A and a second portion of data 1406B.
• the first PPDU 141 OA including the first portion data 1406 A may, when transmitted by the user terminal 120 according to a UL-MU-MIMO operating mode, have a transmission duration that fits the target transmission duration 1420.
• the second portion of the data 1406B may be transmitted by the user terminal 120 in a second PPDU 1410B at a later time (e.g., during a subsequent transmission opportunity).
• the user terminal 120 may build the first PPDU 1410A such that the length of the PPDU matches the target transmission duration indicated by the AP 110.
• FIG. 15 is a time sequence diagram 1500 that shows a user terminal 120 decreasing its transmission data rate to fit a target transmission duration 1520 for a UL-MU-MIMO transmission during a transmission opportunity.
• the dashed arrows in FIG. 15 indicate an increase in transmission duration resulting from the user terminal 120 decreasing its planned transmission data rate.
• an AP 110 may indicate the target transmission duration 1520 in a message granting a transmission opportunity (e.g., trigger frame or CTX message) to the user terminal 120.
• the user terminal 120 may have planned data for transmission 1506 that, when transmitted according to planned operating and transmission parameters, has a planned transmission duration that falls short of the target transmission duration 1520.
• the user terminal 120 may change its operating and transmission parameters to fit the target transmission duration 1520.
• the user terminal 120 may transmit the data 1506 at a lower data rate (e.g., slower MCS) to fit the target transmission duration 1520.
• the user terminal 120 may also adjust a coding scheme and a guard interval for the transmission of uplink data.
• the AP 110 may determine and indicate the MCS adjustment for each the user terminal 120 in the trigger frame or each user terminal 120 may determine its MCS adjustment itself.
• a PPDU 1510 including the data 1506 may, when transmitted by the user terminal 120 at the lower data rate according to a UL-MU-MIMO operating mode, have a transmission duration that fits the target transmission duration 1520.
• FIG. 16 is a time sequence diagram 1600 that shows a user terminal 120 increasing its transmission data rate to fit a target transmission duration 1620 for a UL-MU-MIMO transmission during a transmission opportunity.
• the dashed arrows in FIG. 16 indicate a decrease in transmission duration resulting from the user terminal 120 increasing the transmission data rate of the data for transmission 1606 to produce the PPDU 1610 as transmitted by the user terminal 120.
• an AP 110 may indicate the target transmission duration 1620 in a message granting a transmission opportunity (e.g., a CTX message) to the user terminal 120.
• the user terminal 120 may have planned data for transmission 1606 that, when transmitted, would have a planned transmission duration that exceeds the target transmission duration 1620.
• the user terminal 120 may transmit the data 1606 at a higher data rate (e.g., faster MCS) to fit the target transmission duration 1620.
• the user terminal 120 may also adjust a coding scheme and a guard interval for the transmission of uplink data.
• the AP 110 may determine and indicate the MCS adjustment for each the user terminal 120 in the trigger frame or each user terminal 120 may determine its MCS adjustment itself.
• a PPDU 1610 including the data 1606 may, when transmitted by the user terminal 120 at the higher data rate according to a UL-MU-MFMO operating mode, have a transmission duration that fits the target transmission duration 1620. [00101] FIG.
• FIG. 17 is a time sequence diagram 1700 that shows a user terminal 120 decreasing its level of aggregation to fit a target transmission duration 1720 for a UL-MU-MIMO transmission during a transmission opportunity.
• the dashed arrows in FIG. 17 indicate an increase in transmission duration resulting from the user terminal 120 decreasing the level of aggregation for the data for transmission 1706 to produce the PPDU 1710 as transmitted by the user terminal 120.
• an AP 110 may indicate the target transmission duration 1720 in a message granting a transmission opportunity (e.g., a CTX message) to the user terminal 120.
• the user terminal 120 may have planned data for transmission 1706 that, when transmitted, would have a planned transmission duration that falls short of the target transmission duration 1720.
• the user terminal 120 may decrease a level of data aggregation in a medium access control (MAC) protocol data unit (A-MPDU) or a level of data aggregation in a MAC service data unit (A-MSDU) to fit the target transmission duration 1720.
• the AP 110 may determine and indicate the level of aggregation for each the user terminal 120 in the trigger frame or each user terminal 120 may determine its level of aggregation itself.
• a PPDU 1710 including the data 1706 may, when transmitted by the user terminal 120 at the lower level of data aggregation according to a UL-MU-MFMO operating mode, have a transmission duration that fits the target transmission duration 1720.
• FIG. 18 is a time sequence diagram 1800 that shows a user terminal 120 increasing its level of aggregation to fit a target transmission duration 1820 for a UL-MU-MIMO transmission during a transmission opportunity.
• the dashed arrows in FIG. 18 indicate a decrease in transmission duration resulting from the user terminal 120 increasing the level of aggregation for the planned data for transmission 1806 to produce the PPDU 1810 as transmitted by the user terminal 120.
• an AP 110 may indicate the target transmission duration 1820 in a message granting a transmission opportunity (e.g., a CTX message) to the user terminal 120.
• a transmission opportunity e.g., a CTX message
• the user terminal 120 may have data for transmission 1806 that, when transmitted, would have a planned transmission duration that exceeds the target transmission duration 1820.
• the user terminal 120 may increase a level of data aggregation in an A-MPDU or a level of data aggregation in an A-MSDU to fit the target transmission duration 1820.
• the AP 110 may determine and indicate the level of aggregation for each the user terminal 120 in the trigger frame or each user terminal 120 may determine its level of aggregation itself.
• a PPDU 1810 including the data 1806 may, when transmitted by the user terminal 120 at the higher level of data aggregation according to a UL-MU-MIMO operating mode, have a transmission duration that fits the target transmission duration 1820.
• FIG. 19 is a time sequence diagram 1900 that shows a user terminal 120 adding fill data 1908 to fit a target transmission duration 1920 for a UL-MU-MIMO transmission during a transmission opportunity.
• the dashed arrows in FIG. 19 indicate that the transmission duration of a PPDU 1910 as transmitted by the user terminal 120 remains the same as the data for transmission 1906, except for the fill data 1908.
• an AP 110 may indicate the target transmission duration 1920 in a message granting a transmission opportunity (e.g., a CTX message) to the user terminal 120.
• the user terminal 120 may have planned data for transmission 1906 that, when transmitted, would have a planned transmission duration that falls short of the target transmission duration 1920.
• the user terminal 120 may transmit a PPDU 1910 including base data (e.g., the data for transmission 1906) and may also transmit fill data 1908 according to a UL-MU-MIMO operating mode during the transmission opportunity to fit the target transmission duration 1920.
• the AP 110 may determine and indicate the amount of fill data for each the user terminal 120 in the trigger frame or each user terminal 120 may determine the amount of fill data itself.
• the fill data 1908 may be transmitted before the PPDU 1910.
• the fill data 1908 may include, for example, end-of-frame (EOF) padding delimiters, subframe pad octets, or A-MPDU EOF subframes.
• the fill data 1908 may also be transmitted before the PPDU 1910.
• the fill data 1908 may be added to the beginning of an A-MPDU.
• a combined transmission duration of the PPDU 1910 including the base data and the fill data 1908 may fit the target transmission duration 1920.
• FIG. 20 is a time sequence diagram 2000 that shows a user terminal 120 decreasing its transmission data rate, decreasing its level of aggregation, and adding fill data 2008 to fit a target transmission duration 2020 for a UL-MU-MFMO transmission during a transmission opportunity.
• the dashed arrows in FIG. 20 indicate the change in transmission duration resulting from the user terminal 120 increasing the level of aggregation and increasing the data rate for the data for transmission 2006 to produce the PPDU 2010 as transmitted by the user terminal 120.
• an AP 110 may indicate the target transmission duration 2020 in a message granting a transmission opportunity (e.g., a CTX message) to the user terminal 120.
• a transmission opportunity e.g., a CTX message
• the user terminal 120 may have planned data for transmission 2006 that, when transmitted, would have a planned transmission duration that falls short of the target transmission duration 2020.
• the user terminal 120 may decrease a level of data aggregation in an A-MPDU or an A-MSDU and may transmit the data 2006 and fill data 2008 at a lower data rate (e.g., by adjusting its MCS) to fit the target transmission duration 2020.
• the AP 110 may determine and indicate the level of data aggregation and the MCS for each the user terminal 120 in the trigger frame or each user terminal 120 may determine the level of data aggregation and the MCS itself.
• a combined transmission duration of the PPDU 2010 and the fill data 2008 may fit the target transmission duration 2020.
• FIG. 21 is a time sequence diagram 2100 that shows a user terminal 120 increasing its transmission data rate, increasing its level of aggregation, and adding fill data 2108 to fit a target transmission duration 2120 for a UL-MU-MTMO transmission during a transmission opportunity.
• the dashed arrows in FIG. 21 indicate the change in transmission duration resulting from the user terminal 120 decreasing the level of aggregation and decreasing the data rate for the data for transmission 2106 to produce the PPDU 21 10 as transmitted by the user terminal 120.
• an AP 110 may indicate the target transmission duration 2120 in a message granting a transmission opportunity (e.g., a CTX message) to the user terminal 120.
• a transmission opportunity e.g., a CTX message
• the user terminal 120 may have planned data for transmission 2106 that, when transmitted, would have a planned transmission duration that exceeds the target transmission duration 2120.
• the user terminal 120 may increase a level of data aggregation in an A-MPDU or an A-MSDU and may transmit the data 2006 and fill data 2008 at a higher data rate (e.g., by adjusting its MCS) to fit the target transmission duration 2120.
• the AP 110 may determine and indicate the level of data aggregation and the MCS for each the user terminal 120 in the trigger frame or each user terminal 120 may determine the level of data aggregation and the MCS itself.
• a combined transmission duration of a PPDU 2110, including the data 2106, and the fill data 2008 may fit the target transmission duration 2120.
• FIG. 22 is a time sequence diagram 2200 that shows user terminals 120A-D concurrently transmitting data during a transmission opportunity for a duration that fits a target transmission duration 2220.
• an AP 110 may indicate the target transmission duration 2220 in a message granting a transmission opportunity (e.g., a CTX message) to the user terminals 120A-D.
• the user terminals 120A-D may transmit data (e.g., a PPDU or fill data) to fit the target transmission duration 2220.
• the user terminal 120 A may decrease a level of data aggregation in an A-MPDU or an A-MSDU as described above and may transmit fill data 2208 A and a PPDU 221 OA to fit the target transmission duration 2220.
• the user terminal 120B may increase a level of data aggregation in an A-MPDU or an A-MSDU as described above and may transmit fill data 2208B and a PPDU 2210B to fit the target transmission duration 2220.
• the user terminal 120C may have data for transmission that when transmitted in a PPDU 22 IOC, fits the target transmission duration 2220 without modifying a level of data aggregation or adding fill data.
• the user terminal 120D may transmit a PPDU 2210D and fill data 2208D to fit the target transmission duration 2220.
• the user terminals 120 may use any combination of the changes in data or operating and transmission parameters shown in FIGs. 14-21 in order to fit the target transmission duration.
• One of the benefits of having all of the UL-MU-MIMO transmissions from user terminals 120A-D be the same length is that the power level of the transmissions will remain constant, thereby reducing the negative effects of power fluctuations on the receivers.
• FIG. 23 is another time sequence diagram 2300 that shows user terminals utilizing fill subframes to fill a target transmission duration.
• user terminals 120A-D may each transmit a PSDU that is of a target transmission duration 2320.
• Each PSDU may comprise an A-MPDU frame 2310A-D, and one or more of the A-MPDU frames 2310A-D may include padding (illustrated as "fill" 2308A, 2308B, and 2308D).
• the PSDU may be included in a high-efficiency (HE) trigger based (TB) PPDU.
• HE high-efficiency
• TB trigger based
• one or more transmission parameters may be transmitted by an AP 110 to each of the user terminals 120A-D.
• MCS Mobility Management Function
• duration duration
• transmission power or other PHY parameters
• these parameters can be included in a trigger frame, which can be similar to the CTX 402.
• the AP 110 may transmit the target transmission duration 2320 itself.
• the UTs 120A-D may determine the target transmission duration 2320 based on one or more of the transmission parameters communicated by the AP 110. Once the UTs 120 know the value of the target transmission duration 2320, they may utilize the value to generate their respective A-MPDU frames 2310A-D.
• a UT 120 may start by creating an A-MPDU frame that contains one A-MPDU data "subframe.” Thereafter, the UT 120 may determine whether additional A-MPDU data subframes or A-MPDU delimiter subframes may be added to the A-MPDU frame based at least upon the value of the target transmission duration 2320.
• a UT 120 may only add an A-MPDU data subframe to the A-MPDU frame if the length of the A-MPDU data subframe is greater than zero and if adding the A-MPDU data subframe to the A-MPDU frame will not cause a length of the A-MPDU frame to exceed the target transmission duration 2320.
• a UT 120 may only add an A-MPDU delimiter subframe to the A-MPDU frame if the length of the A-MPDU delimiter subframe is equal to zero and if an EOF field of the A-MPDU delimiter subframe is set to zero.
• the length of an A-MPDU subframe may be indicated in a length field of each MPDU (e.g., an A-MPDU data subframe or an A-MPDU delimiter subframe).
• a UT 120 may be restricted on the contents, the length, or the start spacing of MPDUs contained in the A-MPDU frame or the A-MPDU frame itself. In some aspects, one or more of these restrictions may be determined during association between a UT 120 and an AP 110. In various aspects, one or more of these restrictions may be communicated to the UTs 120 through the use of trigger frames or other messages. Restricting the contents, length, or start spacing may insure that a receiving device is able to properly receive and interpret each MPDU in the A-MPDU frame. In some aspects, a UT 120 may not add an A-MPDU subframe with an EOF field equal to '0' after any A-MPDU subframe with the EOF field set to T.
• a UT 120 may not add an A-MPDU subframe with the EOF field set to T and an MPDU length field set to '0' before an A- MPDU subframe that contains a very high throughput (VHT) single MPDU.
• VHT very high throughput
• a UT 120 has added as many MPDUs to the A-MPDU frame as desired, a UT
• padding information may comprise a sequence of bits set to T or ' ⁇ ', one or more A-MPDU padding subframes, and/or some other information which an AP 110 may understand as padding.
• a UT 120 may determine whether the sum of the current length of the A-MPDU frame plus four is less than the target transmission duration 2320. If the value of the current length is at least four less than the target transmission duration 2320, the UT 120 may add an EOF padding subframe to an EOF padding subframe field in the A-MPDU frame. In certain implementations, the UT increments the current value of the A-MPDU frame length by four. In an aspect, the length of an EOF padding subframe may be four octets. The UT 120 may repeat this process until the current length is less than four (octets) smaller than the target transmission duration 2320.
• A-MPDU frame 2310A + 4 is less than the target transmission duration 2320. Therefore, an EOF padding subframe may be added to an EOF padding subframe field of the A-MPDU frame 231 OA.
• a UT 120 may determine the last subframe in an A-MPDU frame 2310 which has a delimiter with a length greater than zero, and may set an EOF bit of the identified delimiter to be equal to T .
• the following subframes, if any, can be delimiter subframes, each with a length equal to zero and an EOF bit equal to T.
• a UT 120 may determine whether the current length of the A-MPDU frame is less than the target transmission duration 2320. If the value of the current length is less than the target transmission duration 2320, the UT 120 may add an octet of padding to an EOF padding octets subfield in the A-MPDU frame, and increment the current value of the A-MPDU frame length by one. The UT 120 may repeat this process until the current length equal to the target transmission duration 2320. For example, as illustrated, the length of A-MPDU frame 2310B is less than the target transmission duration 2320. Therefore, an octet of padding may be added to an EOF padding octets subfield of the A-MPDU frame 2310B.
• FIG. 24 is a flow chart of a method 2400 for changing data for transmission or operating parameters such that a duration of an UL-MU-MIMO transmission fits a target transmission duration.
• a user terminal 120 may send a request to transmit (e.g., an RTX) to an AP 110 as described herein.
• the user terminal 120 may receive a wireless message from the AP 110 (e.g., a CTX) indicating an uplink transmission opportunity and a target transmission duration for each of a plurality of user terminals 120 as described herein.
• the user terminal 120 may fragment the data for transmission as described herein.
• the user terminal 120 may adjust its transmission data rate to fit the target transmission duration as described herein.
• the user terminal 120 may adjust a level of data aggregation to fit the target transmission duration as described herein.
• the user terminal 120 may add fill data to fit the target transmission duration as described herein.
• the steps at blocks 2403, 2404, 2405, and 2406 are optional and the user terminal 120 may perform any combination of these steps to fit the target transmission duration as described herein.
• the user terminal 120 may transmit a message over the target transmission duration.
• FIG. 25 is a flowchart illustrating a method 2500 for wireless communication involving the generation of an A-MPDU for transmission.
• method 2500 may be implemented by a UT 120.
• the UT 120 receives a message from an AP 110 indicating a target transmission duration for transmission of a physical layer (PHY) service data unit (PSDU) to the AP 110.
• PHY physical layer
• PSDU service data unit
• the message from the AP 110 further indicates a modulation or coding rate and a transmission power level.
• the UT 120 for example, generates an aggregated medium access control (MAC) packet data unit (A-MPDU) frame comprising at least one A-MPDU subframe, the A-MPDU frame having a first length.
• MAC medium access control
• the UT 120 determines whether an additional A-MPDU subframe having a second length may be added to the A-MPDU frame based at least in part on the first length, the second length, and the target transmission duration. For example, if the first length plus the second length is less than the target transmission duration, the UT 120 may add the A-MPDU subframe to the A-MPDU frame.
• the UT 120 for example, includes one or more padding subframes in the A- MPDU frame based at least in part on a comparison between the first length and the target transmission duration. For example, the UT 120 may add a plurality of bits to the A-MPDU frame sufficient to increase the first length to be equal to the target transmission duration.
• the plurality of bits can comprise padding within an A-MPDU subframe' s padding field, an end-of-frame padding delimiter, a subframe padding octet, and/or an A- MPDU end-of-frame subframe.
• the UT 120 may determine whether a remainder of the first length divided by four is equal to zero.
• the UT 120 may include an octet of padding in the A-MPDU frame when the first length is less than the target transmission duration and the remainder is not equal to zero.
• the UT 120 may increment the first length by one for each octet of padding included in the A-MPDU frame.
• the UT 120 may determine whether a difference between the target transmission duration and the first length is greater than four.
• the UT 120 may include an end-of-frame padding subframe in the A- MPDU frame when the difference is greater than four. In some implementations, the UT 120 may increment the first length by four for each end-of-frame padding subframe included in the padding information. Additionally or alternatively, as part of the method 2500, the UT 120, for example, may include a final end-of-frame padding subframe in the A-MPDU frame. In some implementations, the UT 120 may include an octet of padding in the final end-of- frame padding subframe when the first length is less than the target transmission duration. In some implementations, the UT 120 may increment the first length by one for each octet of padding included in the final end-of-frame padding subframe.
• the UT 120 for example, generates the PSDU, the PSDU including the A-MPDU frame and the one or more padding subframes.
• the UT 120 transmits the generated PSDU from over the target transmission duration.
• the UT 120 for example, can transmit the PSDU concurrently with a plurality of UTs 120 (e.g., UTs 120A-D) over the target transmission duration.
• a transmission power level of the transmitted PSDU is substantially constant during the target transmission duration.
• the UT 120 for example, may utilize a transmission data rate, indicated in the message, for transmitting the PSDU.
• the UT 120 may utilize a level of aggregation, indicated in the message, for transmitting the PSDU.
• the UT 120 may utilize an uplink transmission opportunity, determined by the user terminal during a setup phase, for transmitting the PSDU.
• the PSDU can be transmitted within a PHY convergence protocol data unit (PPDU).
• PPDU PHY convergence protocol data unit
• FIG. 26 is another flowchart illustrating another method 2600 for wireless communication including multiple alternative embodiments of generating padding.
• method 2600 may be implemented by a UT 120.
• the UT 120 receives a message from an AP 110 indicating a target transmission duration for transmission of a physical layer (PHY) service data unit (PSDU) to the AP 110.
• the message from the AP 110 further indicates a modulation or coding rate and a transmission power level.
• the UT 120 for example, generates an aggregated medium access control (MAC) packet data unit (A-MPDU) frame having a first length.
• MAC medium access control
• A-MPDU aggregated medium access control
• the UT 120 for example, generates the PSDU, the PSDU including the A-MPDU frame.
• the UT 120 transmits the generated PSDU over the target transmission duration.
• MAC medium access control
• the UT 120 may optionally proceed to one of blocks 2630, 2640, 2650, or 2660.
• the UT 120 determines whether an A-MPDU subframe having a second length may be added to the A-MPDU frame based at least in part on the first length, the second length, and the target transmission duration. For example, if the first length plus the second length is less than the target transmission duration, the UT 120 may add the A-MPDU subframe to the A-MPDU frame.
• the method 2600 may proceed to block 2640 from block 2610 or 2630, where the UT 120, for example, may determine whether a remainder of the first length divided by four is equal to zero. Thereafter, method 2600 may proceed to block 2645, where the UT 120 may include an octet of padding in the A-MPDU frame when the first length is less than the target transmission duration and the remainder is not equal to zero. Optionally, the UT 120 can increment the first length by one for each octet of padding included in the A-MPDU frame. After block 2645, the method 2600 may return to block 2640. Optionally, after block 2640, the method 2600 may return to block 2610.
• the method 2600 may proceed to block 2650 where, the UT 120, for example, may determine whether a difference between the target transmission duration and the first length is greater than four. Thereafter, the method 2600 may proceed to block 2655, where the UT 120 can include an end-of-frame padding subframe in the A-MPDU frame when the difference is greater than four. Optionally, the UT 120 can increment the first length by four for each end-of-frame padding subframe included in the padding information. After block 2655, the method 2600 may return to block 2650. Optionally, after block 2650, the method 2600 may return to block 2610.
• the method 2600 may proceed to block 2660, where the UT 120, for example, may determine whether the first length is less than the target transmission duration. Thereafter, the method 2600 may proceed to block 2665, where the UT 120 can include a final end-of-frame padding subframe in the A-MPDU frame. In some implementations, the UT 120 can include an octet of padding in the final end-of-frame padding subframe when the first length is less than the target transmission duration. Optionally, the UT 120 can increment the first length by one for each octet of padding included in the final end-of-frame padding subframe. After block 2665, the method 2600 may return to block 2660. Optionally, after block 2660, the method 2600 may return to block 2610.
• the UT 120 can transmit the
• a transmission power level of the transmitted PSDU is substantially constant during the target transmission duration.
• the UT 120 may utilize a transmission data rate, indicated in the message, for transmitting the PSDU.
• the UT 120 may utilize a level of aggregation, indicated in the message, for transmitting the PSDU.
• the UT 120 for example, may utilize an uplink transmission opportunity, determined by the user terminal during a setup phase, for transmitting the PSDU.
• the PSDU can be transmitted within a PHY convergence protocol data unit (PPDU).
• PPDU PHY convergence protocol data unit
• a UT 120 for wireless communication may perform one or more of the functions of methods 2400, 2500, 2600, in accordance with certain embodiments described herein.
• the UT 120 may comprise means for receiving a message.
• the means for receiving can be implemented by the receiver 312, the processor 304, the antenna 316, the DSP 320, and/or the signal detector 318 (FIG. 3).
• the UT 120 may comprise means for generating an aggregated medium access control (MAC) packet data unit (A-MPDU) frame.
• the means for generating can be implemented by the transmitter 310, the processor 304, the antenna 316, the DSP 320, and/or the signal detector 318 (FIG. 3).
• the UT 120 may further comprise means for determining whether an additional A-
• the MPDU subframe having a second length may be added to the A-MPDU frame.
• the means for generating for transmission to the plurality of receiving devices can be implemented by the receiver 312, the processor 304, the antenna 316, the DSP 320, and/or the signal detector 318 (FIG. 3).
• the UT 120 may further comprise means for including one or more padding subframes in the A-MPDU frame.
• the means for including can be implemented by the receiver 312, the transmitter 310, the processor 304, the antenna 316, the DSP 320, and/or the signal detector 318 (FIG. 3).
• the UT 120 may comprise means for generating the PSDU.
• the means for generating can be implemented by the transmitter 310, the processor 304, the antenna 316, the DSP 320, and/or the signal detector 318 (FIG. 3).
• the UT 120 may comprise means for transmitting the generated PSDU.
• the means for transmitting can be implemented by the transmitter 310, the processor 304, the antenna 316, the DSP 320, and/or the signal detector 318 (FIG. 3).
• DSP digital signal processor
• ASIC application specific integrated circuit
• FPGA field programmable gate array signal
• PLD programmable logic device
• a general purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller or state machine.
• a processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
• the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored on or transmitted over as one or more instructions or code on a computer- readable medium.
• Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another.
• a storage media may be any available media that can be accessed by a computer.
• such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer.
• any connection is properly termed a computer-readable medium.
• the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave
• DSL digital subscriber line
• wireless technologies such as infrared, radio, and microwave
• Disk and disc includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu- ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers.
• computer readable medium may comprise non- transitory computer readable medium (e.g., tangible media).
• computer readable medium may comprise transitory computer readable medium (e.g., a signal). Combinations of the above should also be included within the scope of computer- readable media.
• the methods disclosed herein comprise one or more steps or actions for achieving the described method.
• the method steps and/or actions may be interchanged with one another without departing from the scope of the claims.
• the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims.
• modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by a user terminal and/or base station as applicable.
• a user terminal and/or base station can be coupled to a server to facilitate the transfer of means for performing the methods described herein.
• various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.), such that a user terminal and/or base station can obtain the various methods upon coupling or providing the storage means to the device.
• storage means e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.
• CD compact disc
• floppy disk etc.
• any other suitable technique for providing the methods and techniques described herein to a device can be utilized.

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• 2016
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