Classifications

• • 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
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/02—Arrangements for detecting or preventing errors in the information received by diversity reception
  • H04L1/06—Arrangements for detecting or preventing errors in the information received by diversity reception using space diversity
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/1607—Details of the supervisory signal
  • H04L1/1614—Details of the supervisory signal using bitmaps
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L1/00—Arrangements for detecting or preventing errors in the information received
  • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
  • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
  • H04L1/1607—Details of the supervisory signal
  • H04L1/1685—Details of the supervisory signal the supervisory signal being transmitted in response to a specific request, e.g. to a polling signal
• • 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
  • H04L5/0001—Arrangements for dividing the transmission path
  • H04L5/0003—Two-dimensional division
  • H04L5/0005—Time-frequency
  • H04L5/0007—Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT
  • H04L5/001—Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT the frequencies being arranged in component carriers
• • 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
  • H04L5/0032—Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
• • 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
  • H04L5/0037—Inter-user or inter-terminal allocation
• • 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
  • H04L5/0058—Allocation criteria
  • H04L5/0064—Rate requirement of the data, e.g. scalable bandwidth, data priority
• • 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
  • H04L5/0091—Signaling for the administration of the divided path
  • H04L5/0094—Indication of how sub-channels of the path are allocated
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
  • H04L69/30—Definitions, standards or architectural aspects of layered protocol stacks
  • H04L69/32—Architecture of open systems interconnection [OSI] 7-layer type protocol stacks, e.g. the interfaces between the data link level and the physical level
  • H04L69/322—Intralayer communication protocols among peer entities or protocol data unit [PDU] definitions
  • H04L69/324—Intralayer communication protocols among peer entities or protocol data unit [PDU] definitions in the data link layer [OSI layer 2], e.g. HDLC
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W84/00—Network topologies
  • H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
  • H04W84/10—Small scale networks; Flat hierarchical networks
  • H04W84/12—WLAN [Wireless Local Area Networks]
• • 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
  • H04L5/0001—Arrangements for dividing the transmission path
  • H04L5/0014—Three-dimensional division
  • H04L5/0023—Time-frequency-space
• • 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

Definitions

• This disclosure relates to wireless communication systems, such as Wireless
• WLANs Local Area Networks
• Wireless communication systems can include multiple wireless
• a wireless communication device When operating in an infrastructure mode, a wireless communication device called an access point (AP) provides connectivity with a network, such as the Internet, to other wireless communication devices, e.g., client stations or access terminals (AT).
• AP access point
• AT access terminal
• Various examples of wireless communication devices include mobile phones, smart phones, wireless routers, and wireless hubs.
• wireless communication electronics are integrated with data processing equipment such as laptops, personal digital assistants, and computers.
• Wireless communication systems can use one or more wireless communication technologies, such as orthogonal frequency division multiplexing (OFDM).
• OFDM orthogonal frequency division multiplexing
• a data stream is split into multiple data substreams.
• Such data substreams are sent over different OFDM subcarriers, which can be referred to as tones or frequency tones.
• WLANs such as those defined in the Institute of Electrical and Electronics Engineers (IEEE) wireless communications standards, e.g., IEEE 802.1 la, IEEE 802.11 ⁇ , or IEEE 802.1 lac, can use OFDM to transmit and receive signals.
• IEEE Institute of Electrical and Electronics Engineers
• Wireless communication devices in a WLAN can use one or more protocols for medium access control (MAC) and physical (PHY) layers.
• MAC medium access control
• PHY physical
• a wireless communication device can use a Carrier Sense Multiple Access (CSMA) with Collision Avoidance (CA) based protocol for a MAC layer and OFDM for the PHY layer.
• CSMA Carrier Sense Multiple Access
• CA Collision Avoidance
• Some wireless communication systems use a single-in-single-out (SISO) communication approach, where each wireless communication device uses a single antenna.
• SISO single-in-single-out
• MIMO multiple-in-multiple-out
• a MIMO-based wireless communication device can transmit and receive multiple spatial streams over multiple antennas in each of the tones of an OFDM signal.
• the present disclosure includes systems and techniques for wireless communications.
• a technique for wireless communications includes obtaining data for a transmission to a wireless communication device(s) via a physical (PHY) frame, including one or more medium access control (MAC) data units, such as MAC protocol data units (MPDUs), that encapsulate the data in a physical (PHY) frame, determining a length of a MAC layer pad based on a number of symbols associated with the PHY frame, including, in response to the length of the MAC layer pad being greater than zero, the MAC layer pad in the PHY frame after the one or more MAC data units, determining a length of a PHY layer pad based on remaining available bits in the PHY frame, including, in response to the length of the PHY layer pad being greater than zero, the PHY layer pad in the frame after the MAC layer pad, and transmitting the PHY frame to the wireless communication device(s).
• MAC medium access control
• MPDUs MAC protocol data units
• the described systems and techniques can be implemented in electronic circuitry, computer hardware, firmware, software, or in combinations of them, such as the structural means disclosed in this specification and structural equivalents thereof.
• This can include at least one computer-readable medium embodying a program operable to cause one or more data processing apparatus (e.g., a signal processing device including a programmable processor) to perform operations described.
• program implementations can be realized from a disclosed method, system, or apparatus, and apparatus implementations can be realized from a disclosed system, computer-readable medium, or method.
• method implementations can be realized from a disclosed system, computer-readable medium, or apparatus, and system implementations can be realized from a disclosed method, computer- readable medium, or apparatus.
• one or more disclosed embodiments can be implemented in various systems and apparatus, including, but not limited to, a special purpose data processing apparatus (e.g., a wireless communication device such as a wireless access point, a remote environment monitor, a router, a switch, a computer system component, a medium access unit), a mobile data processing apparatus (e.g., a wireless client, a cellular telephone, a smart phone, a personal digital assistant (PDA), a mobile computer, a digital camera), a general purpose data processing apparatus such as a computer, or combinations of these.
• a special purpose data processing apparatus e.g., a wireless communication device such as a wireless access point, a remote environment monitor, a router, a switch, a computer system component, a medium access unit
• a mobile data processing apparatus e.g., a wireless client, a cellular telephone, a smart phone, a personal digital assistant (PDA), a mobile computer, a digital camera
• PDA personal digital assistant
• FIG. 1 shows an example of a communication process based on a frame padding technique.
• FIG. 2 shows an example of a wireless network with two wireless
• FIG. 3 shows an example of a wireless communication device architecture.
• FIG. 4 shows an example of a spatial communication flow layout that includes
• FIG. 5 shows an example of a transmission layout that includes MAC and
• FIG. 6 shows an example of a transmission layout that includes MAC and
• FIG. 7 shows an example of a spatial communication flow with long data unit signaling and acknowledgements.
• FIGS. 8A, 8B, and 8C show an example of communication flow layout associated with reduced block acknowledgement overhead.
• FIGS. 9A and 9B show examples of a multi-user frame transmission layout and associated acknowledgement responses.
• FIG. 10 shows another example of a spatial communication flow layout.
• FIG. 1 1 shows another example of a spatial communication flow layout.
• This disclosure provides details and examples of technologies for wireless local area networks, including systems and techniques for including frame padding in wireless transmissions and processing received transmissions that include frame padding.
• An example of a frame padding technique includes operating a wireless communication device to determine MAC layer padding and PHY layer padding based on the number of symbols required to transmit the frame.
• Potential advantages of one or more of the described technologies can include an increased system bandwidth, backwards compatibility with older standards, or both.
• the techniques and architectures presented herein can be implemented in a variety of wireless communication systems such as ones based on IEEE 802.1 lac.
• FIG. 1 shows an example of a communication process based on a frame padding technique.
• a communication process implemented by a device such an access point device or a client device can selectively include frame padding in a transmission. The inclusion of frame padding can be determined based on a number of symbols required for transmission.
• the communication process obtains data for a transmission to a wireless communication device(s). Obtaining the data for a transmission can include receiving data for two or more wireless communication devices from two or more sources such as applications, servers via a network, or storage devices.
• the communication process arranges obtained data for transmission based on a Space Division Multiple Access (SDMA) technique to concurrently transmit data to multiple devices.
• SDMA Space Division Multiple Access
• the process includes one or more MPDUs that encapsulate the data in a PHY frame.
• a MAC layer can generate an aggregated MPDU (A-MPDU) that includes the one or more MPDUs and associated one or more MPDU delimiters.
• a PHY layer can include the A-MPDU into the PHY frame.
• the size of a MPDU delimiter is 4 octets.
• the PHY frame can include two or more spatially steered frames, with respective A- MPDUs, that are intended for two or more devices.
• the communication process determines a length of a MAC layer pad based on a number of symbols associated with the PHY frame.
• a MAC layer can generate the one or more MPDUs and the MAC layer pad.
• a PHY layer can reduce the length of the MAC layer pad to reduce a number of symbols required for the PHY frame.
• a MAC layer can determine a MAC layer pad based on a 4- octet boundary.
• a PHY layer if required, can adjust the MAC layer pad based on a symbol boundary associated with the PHY frame.
• the PHY layer can add additional PHY layer bits such as PHY pad bits and convolutional code (CC) tail bits.
• CC convolutional code
• the process includes, in response to the length of the MAC layer pad being greater than zero, the MAC layer pad in the PHY frame after the one or more MPDUs.
• the MAC layer includes the MAC layer pad into an A-MPDU.
• Including the MAC layer pad in a frame can include including one or more padding delimiters after the one or more MPDUs in an A-MPDU.
• a padding delimiter can be based on a MPDU delimiter format.
• Including the MAC layer pad in a frame can include including a MAC pad after the one or more padding delimiters.
• a MAC pad can be an integer number of octets in length that is less than four octets (e.g., 1, 2, or 3 octets in length, or 0 if not required).
• a MAC layer pad can include the one or more padding delimiters and the MAC pad.
• a padding delimiter can include an end-of-frame (EOF) flag to inform a wireless communication device to stop receiving a PHY frame after a corresponding padding delimiter. Based on the EOF flag, a receiving wireless communication device can shut-off receiver circuitry to reduce power consumption.
• EEF end-of-frame
• the communication process determines a length of a PHY layer pad based on remaining available bits in the PHY frame. Determining the remaining available bits in the PHY frame can include accessing a length of the PHY frame, and accessing the length of an A-MPDU and the length of PHY tail bits to determine a length of a portion of the PHY frame to be filed with a PHY layer pad.
• the process includes, in response to the length of the PHY layer pad being greater than zero, the PHY layer pad in the frame after the MAC layer pad.
• the communication process limits the length of the PHY layer pad to less than 32 bits. In some other implementations, the communication process limits the length of the PHY layer pad to less than 8 bits. Tail bits can be appended after the PHY layer pad.
• the communication process transmits the PHY frame to the wireless communication device(s).
• Transmitting a PHY frame can include transmitting two or more spatially steered frames that concurrently provide data to two or more devices.
• the ends of the steered frames can be aligned to facilitate transmissions of acknowledgements.
• One or more of the steered frames can include MAC layer padding, PHY layer padding, or both.
• An amount of padding can be based on a maximum length that is determined by lengths of the steered frames.
• ends of the steered frames are aligned to have the same length, which is signaled by an omni-directional PHY signaling field that is common to the steered frames.
• a transmitting device can include one or more padding delimiters after a last non-zero-length A-MPDU subframe of the A-MPDU, where each of the one or more padding delimiters are four octets in length.
• the transmitting device can include a MAC pad after the one or more padding delimiters.
• a padding delimiter can indicate a MPDU length of zero.
• the MAC pad is an integer number of octets in length, which is less than four octets.
• a MAC pad can be a partial EOF padding delimiter.
• the MAC layer pad can include the one or more padding delimiters and the MAC pad.
• the one or more padding delimiters include an end-of-frame flag to inform a recipient device to stop receiving a remaining portion of the PHY frame.
• a MAC layer pad can include a dword pad.
• a transmitting device includes a dword pad in the last non-zero-length A-MPDU subframe of the A-MPDU.
• a dword pad, padding delimiters, and the MAC byte pad can be added one by one whenever there are still available bytes left in the PHY frame, exclusive of the tail bits.
• the device can add a dword pad, byte by byte, until the last A-MPDU subframe reaches a 4-byte boundary or reaches the last byte of the PHY frame.
• the device can add one or more padding delimiters, one-by-one, whenever the remaining bytes are larger than 4 bytes.
• a MAC pad can be added to fill in one or more remaining bytes.
• a RX PHY processes the received PHY frame till the last byte of the frame, excluding tail bits, and passes the received data to a RX MAC.
• the RX MAC processes the received A-MPDU subframe one-by-one until detecting the EOF padding delimiter or until the remaining data after the last processed A-MPDU subframe is less than 4 bytes.
• a transmitting device makes a MAC layer pad reach to a last 8-bit boundary of the PHY frame, exclusive of PHY tail bits in the PHY frame, and limits the length of the PHY layer pad to less than 8 bits. In some other implementations, a transmitting device makes a MAC layer pad reach to the last 32-bit boundary of the PHY frame, exclusive of PHY tail bits in the PHY frame, and limits the length of the PHY layer pad to less than 32 bits.
• a wireless communication device can include circuitry to access a wireless communication interface and processor electronics configured to perform one or more techniques described herein.
• a wireless communication interface can include circuitry to transmit and receive wireless communication signals.
• FIG. 2 shows an example of a wireless network with two wireless communication devices.
• Wireless communication devices 205, 207 such as an access point (AP), base station (BS), wireless headset, access terminal (AT), client station, or mobile station (MS) can include circuitry such as processor electronics 210, 212.
• Processor electronics 210, 212 can include one or more processors that implement one or more techniques presented in this disclosure.
• Wireless communication devices 205, 207 include circuitry such as transceiver electronics 215, 217 to send and receive wireless signals over one or more antennas 220a, 220b, 222a, 222b.
• Wireless communication devices 205, 207 can communicate with one or more types of devices (e.g., devices based on different wireless communication standards) such as a high-throughout (HT) device (e.g., IEEE 802.1 In based device) or a very high-throughout (VHT) device (e.g., IEEE 802.1 lac based device).
• HT high-throughout
• VHT very high-throughout
• transceiver electronics 215, 217 include integrated transmitting and receiving circuitry. In some implementations, transceiver electronics 215, 217 include multiple radio units. In some implementations, a radio unit includes a baseband unit (BBU) and a radio frequency unit (RFU) to transmit and receive signals. Transceiver electronics 215, 217 can include one or more of: detector, decoder, modulator, and encoder. Transceiver electronics 215, 217 can include one or more analog circuits.
• Wireless communication devices 205, 207 include one or more memories 225, 227 configured to store information such as data, instructions, or both. In some implementations, wireless communication devices 205, 207 include dedicated circuitry for transmitting and dedicated circuitry for receiving. In some implementations, a wireless communication device 205, 207 is operable to act as a serving device (e.g., an access point), or a client device.
• a first wireless communication device 205 can transmit data to one or more devices via two or more spatial wireless communication channels such as orthogonal spatial subspaces, e.g., orthogonal SDMA subspaces.
• the first wireless communication device 205 can concurrently transmit data to a second wireless communication device 207 using a spatial wireless channel and can transmit data to a third wireless communication device (not shown) using a different spatial wireless channel.
• the first wireless communication device 205 implements a space division technique to transmit data to two or more wireless communication devices using two or more spatial multiplexing matrices to provide spatially separated wireless channels in a single frequency range.
• Wireless communication devices such as a MIMO enabled access point
• a MIMO enabled access point can participate in sounding to obtain channel state information for each of the client wireless communication devices.
• the access point can compute spatial multiplexing matrices, such as spatial steering matrices, based on the different channel state information to spatially separate signals to different client devices.
• FIG. 3 shows an example of a wireless communication device architecture, which can include the various implementation details described herein.
• a wireless communication device 350 can produce signals for different clients that are spatially separated by respective spatial multiplexing matrices W e.g., steering matrices. Each W l is associated with a subspace.
• the wireless communication device 350 includes a MAC module 355.
• the MAC module 355 can include one or more MAC control units (MCUs) (not shown).
• the wireless communication device 350 includes three or more encoders 360a, 360b, 360c that receive data streams, from the MAC module 355, for N respective client devices.
• the encoders 360a-c can perform encoding, such as a forward error correction (FEC) encoding technique to produce respective encoded streams.
• FEC forward error correction
• Modulators 365a, 365b, 365c can perform modulation on respective encoded streams to produce modulated streams provided to spatial mapping modules 370a, 370b, 370c.
• the spatial mapping modules 370a-c can access a memory (not shown) to retrieve a spatial multiplexing matrix W t associated with a data stream's intended client device. In some implementations, the spatial mapping modules 370a-c access the same memory, but at different offsets to retrieve different matrices.
• An adder 375 can sum spatially steered outputs from the spatial mapping modules 370a-c.
• An Inverse Fast Fourier Transform (IFFT) module 380 can perform an IFFT on an output of the adder 375 to produce a time domain signal.
• a digital filtering and radio module 385 can filter the time domain signal and amplify the signal for transmission via an antenna module 390.
• An antenna module 390 can include multiple transmit antennas and multiple receive antennas. In some implementations, an antenna module 390 is a detachable unit that is external to a wireless communication device 350.
• a wireless communication device 350 includes one or more integrated circuits (ICs).
• a MAC module 355 includes one or more ICs.
• a wireless communication device 350 includes an IC that implements the functionality of multiple units and/or modules such as a MAC module, MCU, BBU, or RFU.
• a wireless communication device 350 includes a host processor that provides a data stream to a MAC module 355 for transmission.
• a wireless communication device 350 includes a host processor that receives a data stream from the MAC module 355.
• a host processor includes a MAC module 355.
• a MAC module 355 can generate a MAC Service Data Unit (MSDU) based on data received from higher level protocols such a Transmission Control Protocol over Internet Protocol (TCP/IP).
• a MAC module 355 can generate a MAC Protocol Data Unit (MPDU) based on a MSDU.
• MPDU MAC Protocol Data Unit
• a MAC module 355 can generate a Physical Layer Service Data Unit (PSDU) based on a MPDU.
• PSDU Physical Layer Service Data Unit
• a wireless communication device can generate a data unit (e.g., a MPDU or a PSDU) that is intended for a single wireless communication device recipient.
• a Physical Layer Protocol Data Unit (PPDU) can encapsulate a PSDU.
• a wireless communication device 350 can perform omni-directional transmissions that are intended for multiple client devices.
• the MAC module 355 can operate a single data pathway between the MAC module 355 and the IFFT module 380.
• the device 350 can perform steered transmissions that concurrently provide separate data to multiple client devices.
• the device 350 can alternate between omni-directional transmissions and steered transmissions.
• the device 350 can transmit a first PPDU to a first client via a first spatial wireless channel and concurrently transmit a second PPDU to a second client via a second spatial wireless channel.
• transmission signals can include one or more legacy training fields (L-TFs) such as a Legacy Short Training Field (L-STF) or Legacy Long Training Field (L-LTF).
• L-STF Legacy Short Training Field
• L-LTF Legacy Long Training Field
• Transmission signals can include one or more Legacy Signal Fields (L-SIGs).
• L-SIGs Legacy Signal Fields
• VHT- SIGs VHT Signal Fields
• Transmission signals can include one or more VHT training fields (VHT-TFs).
• VHT-STF VHT Short Training Field
• VHT-LTF VHT Long Training Field
• Transmission signals can include different types of data fields such as VHT -Data fields.
• FIG. 4 shows an example of a spatial communication flow layout that includes
• VHT-Data segments include respective aggregated MPDUs (A- MPDUs) 415a, 415b, and 415c.
• A-MPDUs 415a-c each include one or more subframes.
• the SDMA enabled device Prior to transmitting the A-MPDUs 415a-c, the SDMA enabled device transmits a L-SIG 405 and one or more VHT-SIGs 410 to the recipient devices.
• the L-SIG 405 includes information that indicates a remaining duration of a PHY frame 401 (e.g., the number of symbols from the end of the L-SIG 405 to the end of a PPDU).
• a client device can determine the end of the frame 401 based on a length field and rate field included in the L-SIG 405.
• the end of the frame 401 is based on the longest VHT-Data segments in the SDMA based transmission. Note that shorter VHT-Data segments align with the length of the longest VHT-Data segment by including padding.
• a VHT-SIG 410 includes information that indicates a remaining duration of the PHY frame 401 (e.g. from the end of the VHT-SIGs 410 to the end of a PPDU). Based on the depicted communication layout, the remaining duration indicated by the VHT-SIGs 410 is shorter than the remaining duration indicated by the L-SIG 405. In some other implementations, a VHT- SIG 410 steered to a destination device indicates the length of the useful data, exclusive of the MAC layer padding, included in the A-MPDU transmitted to the destination device.
• An amount of padding can be based on a remaining symbol duration, which is indicated by the L-SIG 405, the VHT-SIGs 410, or both.
• the transmitting device if required, inserts MAC padding 420a, 420b after an end of an A-MPDU 415b, c.
• An A-MPDU can include MAC padding.
• MAC padding 420a, b can include end-of-frame (EOF) signaling such as one or more EOF padding delimiters.
• a padding delimiter can be based on a MPDU delimiter format.
• an EOF padding delimiter includes an EOF flag, a MPDU length field that is set to zero, a checksum, and a delimiter signature.
• the AP device inserts PHY padding 425a, 425b, 425c after an end of the A-MPDU 415a-c, or, if present, after an end of the MAC padding 420a, b.
• the AP inserts tail bits such as convolutional code (CC) tail bits 430a, 430b, 430c.
• CC convolutional code
• the position of the point can be different for each client device communication.
• the amounts of MAC padding 420a, b for respective client device communications in the frame 401 can be different.
• Determining whether to add padding can include checking whether the end of the last subframe of an A-MPDU, exclusive of MAC layer padding 420a, 420b, plus CC tail bits 430b, 430c is within the end of a last symbol boundary determined by a L-SIG 405 duration field, a VHT-SIG 410 duration field, or both.
• a TX MAC layer can pad an A-MPDU to a 32-bit boundary, e.g. pad the last A-MPDU subframe to a 32- bit boundary, keep adding padding delimiters until no more padding delimiters can be added, or both.
• the TX PHY layer Based on the A-MPDU, which may include padding, the TX PHY layer appends a PHY pad, which is less than 32 bits, and PHY tail bits to extend the data to the last symbol boundary.
• a TX MAC layer can pad the last A-MPDU subframe of the A-MPDU to a 32-bit boundary, keep adding padding delimiters until all available bits in the corresponding PPDU are filled, or both.
• the A-MPDU plus PHY tail bits may exceed the last symbol boundary.
• the TX PHY layer can reduce the size of MAC layer padding until MAC layer padding, a PHY pad, and PHY tail bits 430 fit in the last symbol boundary of a frame.
• FIG. 5 shows an example of a transmission layout that includes MAC and
• a device can produce a transmission, which includes a PPDU 500 which was generated via multiple protocol layers, including a MAC layer and a PHY layer.
• the PPDU 500 includes an A-MPDU, which contains multiple subframes 515a, 515b, 515n.
• a TX MAC layer appends a MAC layer pad such as a MAC byte pad 520 to the end of the last subframe 515n of the A-MPDU to pad to the end of the last byte boundary 530 in the PPDU exclusive of the tail bits.
• the last subframe 515n of the A-MPDU can include a padding delimiter; and, in some cases, one or more subframes preceding the last subframe 515n can include a padding delimiter.
• a TX PHY layer Based on a TX MAC layer output, a TX PHY layer appends data bits to the end of the MAC byte pad 520 to fill to the end of a symbol boundary 540, which is determined by a VHT-SIG 505 duration field. In this example, the TX PHY layer appends a PHY pad 535 after the end of the MAC byte pad 520 and appends tail bits 545 after the end of the PHY pad 535.
• the size of the PHY pad 535 can be up to 7 bits in length (e.g., less than one byte in length); note that the A-MPDU, together with a service field 507 and tail bits 545, can occupy all available bytes in a PHY payload. In another example based on a different ordering, the TX PHY layer appends tail bits after the end of the MAC byte pad and appends a PHY pad after the end of the tail bits.
• the combined size of the MAC byte pad 520 and the PHY pad 535 can be less than 32 bits.
• the size of the MAC pad 520 can be 1, 2, or 3 octets in length.
• a transmitting device can determine whether to add padding based on one or more conditions. Determining whether to add padding can include checking whether the end of the last subframe 515n of an A-MPDU, exclusive of MAC layer padding, plus tail bits 545 is within the end of the last symbol boundary 540 determined by a L-SIG 503 duration field or a VHT-SIG 505 duration field.
• a TX MAC layer can pad the last A-MPDU subframe 515n to a 32-bit boundary and pass the A-MPDU to a TX PHY layer.
• the TX PHY layer can reduce the size of MAC byte pad 520 until the MAC byte pad 520, PHY pad 535, and tail bits 545 extend to the last symbol boundary 540. In some other implementations, the TX PHY layer removes one or more padding bits that extend past the end of the last symbol boundary 540 less the length of the tail bits 545, and then adds the tail bits 545.
• a RX PHY layer passes transmission data to a RX MAC layer until the last byte boundary 530.
• the RX PHY layer disregards the remaining content of the transmission 500, e.g., PHY pad 535 and tail bits 545.
• the end of the last A-MPDU subframe 515n can be determined by the length in the delimiter of the last A-MPDU subframe 515n. Based on the determined end, the RX MAC layer removes the remaining content e.g., MAC byte pad 520.
• a RX PHY layer passes received data to a RX MAC layer in 32-bit units until the remaining bits (excluding tail bits) are less than 8 bits or until the bits in the last symbol are exhausted.
• a RX MAC layer identifies the end of the last A-MPDU subframe based on the length in the delimiter of the last subframe 515n.
• FIG. 6 shows an example of a transmission layout that includes MAC and
• a device can produce a transmission 600 that includes a MAC layer pad that contains EOF padding delimiters 610a, 610b and a MAC byte pad 620.
• the transmission 600 includes an A-MPDU, which contains multiple subframes 615a, 615b, 615n.
• a TX MAC layer appends one or more EOF padding delimiters 610a, 610b and a MAC byte pad 620 after the end of the last subframe 615n of the A-MPDU to pad to the end of the last byte boundary 630, exclusive of PHY tail bits 645.
• the MAC byte pad 620 is included after the last padding delimiter 610b.
• an EOF flag is added to a delimiter of the last A-MPDU subframe 615n.
• each subframe 615a, 615b, including the last subframe 615n, in an A- MPDU is padded to a 32-bit boundary; this padding is called a dword pad, which can be 0, 1, 2, or 3 bytes in length.
• the dword pad added to the end of the last A-MPDU subframe 615n can be considered as a part of the MAC layer pad.
• the TX PHY layer appends a PHY pad 635, which is typically less than one byte, to the end of the MAC byte pad 620 and appends tail bits 645 after the end of the PHY pad 635.
• the size of the PHY pad 635 is based on the symbol boundary 640 determined by a PHY signaling duration field, such as a L-SIG 603 duration field or a VHT-SIG 605 duration field, and additional PHY layer bits such as tail bits that are to be included into the transmission 600.
• a PHY signaling duration field such as a L-SIG 603 duration field or a VHT-SIG 605 duration field
• additional PHY layer bits such as tail bits that are to be included into the transmission 600.
• a RX PHY layer Based on a reception of the transmission 600, a RX PHY layer passes transmission data to a RX MAC layer until the last byte boundary 630.
• the RX PHY layer removes the remaining content of the transmission 600, e.g., PHY pad 635 and tail bits 645, before passing data to the RX MAC layer.
• the RX MAC layer detects and removes the EOF padding delimiters 610a, 610b. For example, once the RX MAC layer detects an EOF padding delimiter, the RX MAC layer can discard the remaining received data after the EOF padding delimiter and can signal the RX PHY layer to stop receiving immediately to save power. In some cases, the RX MAC layer removes the MAC byte pad 620.
• a received A-MPDU is processed, in multiples of 32-bits, until a remaining part is less than 32 bits. If the remaining part is not covered by either an A-MPDU subframe or a padding delimiter, the remaining part (e.g., MAC byte pad 620) is removed.
• the last A-MPDU subframe in an A-MPDU can include a dword pad and one or more EOF padding delimiters.
• the MAC pad extends the A-MPDU to a 32-bit boundary.
• a device can determine the size of a MAC pad based on one or more MAC padding rules.
• the MAC pad is added to extend the last A-MPDU subframe to the last 32-bit boundary.
• a RX PHY layer can pass received bits, excluding received tail bits, to a RX MAC layer using a 32-bit interface.
• the RX MAC layer based on detecting an EOF delimiter in a MPDU, or detecting a padding delimiter, can remove the bits that follow the MPDU or the padding delimiter. If an EOF delimiter is not detected, the RX MAC layer can disregard the last received 32-bit not covered by an A-MPDU subframe.
• a MAC pad is added to extend the last A-MPDU subframe to the last 8-bit boundary.
• the device can include an EOF flag in the last subframe based on the last A-MPDU subframe (including the last EOF padding delimiter) not reaching a 32-bit boundary.
• a RX PHY layer can pass received bits till the last 8-bit boundary to a RX MAC layer.
• the RX MAC layer can process bits received from a RX PHY layer until the remaining bits are less than 8-bits.
• the RX MAC layer can disregard the remaining bits.
• a device can signal the presence of an extended length PHY frame based on a combination of fields in different locations in a PHY frame.
• a device can include, in a first PHY signaling field (e.g., a L-SIG field), information to indicate a first length of the PHY frame, and include, in a second PHY signaling field (e.g., a VHT-SIG field), information to indicate a second length of the PHY frame.
• the second PHY signaling field can be used to indicate an end of useful data in a PHY frame for a recipient device.
• FIG. 7 shows an example of a spatial communication flow with long data unit signaling and acknowledgements.
• a L-SIG 705 includes a rate field and a length field (L_LENGTH). Based on the L-SIG 705 rate field indicating a data rate of 6Mbps, binary phase-shift keying (BPSK) modulation, and 1 ⁇ 2 code rate, there are 3 octets per symbol, which provides for a max L-SIG duration of 5.464 ms.
• a VHT transmission can include a VHT-SIG-A 710 that signals a presence of a PPDU longer than 5.464 ms, e.g., a VHT PPDU 701.
• a VHT-SIG-A 710 in some implementations, includes an extended length
• E_LENGTH (E_LENGTH) subfield to indicate a presence of a PPDU longer than 5.464 ms. Based on a L_LENGTH and E_LENGTH, a VHT PPDU duration can be expressed by: ⁇ L LENGTH + E LENGTH
• the length signaling bits of a PPDU are extended to 14 bits, which can indicate a max duration of 21.85 ms.
• a legacy device may be only able to decode the L-SIG 705 of the transmission. If the PPDU duration is larger than 5.464 ms, a clear-to-send (CTS) message can be transmitted before the long PPDU transmission (e.g., longer than 5.464 ms) to prevent legacy devices from transmitting during the long PPDU transmission.
• CTS clear-to-send
• VHT-SIG-A 710 includes a "Long PPDU” subfield, which can be 1-bit, to indicate a long PPDU.
• the "Long PPDU” subfield can be set to indicate a long PPDU duration (e.g., a PPDU duration being greater than 5.464 ms).
• a length field in the L-SIG 705 can be set based on a rate lower than 6Mbps (e.g. 2Mbps or 1Mbps), while the rate field in L-SIG 705 is set as 6Mbps.
• a VHT device which is capable of processing a long PPDU, can calculate a PPDU duration based on the L-SIG 705 length field. For example, the VHT device can calculate a VHT PPDU duration based on (l + L_LENGTH ) x 4//s , where
• L_LENGTH denotes a value in the L-SIG 705 length field.
• a message such as a CTS-to-Self can be transmitted before the long PPDU transmission (e.g., longer than 5.464 ms) to prevent legacy devices from transmitting during the long PPDU transmission.
• Other long PPDU signaling techniques are possible.
• An AP can use an implicit ACK policy to cause a first client (e.g., STA 1) to transmit an acknowledgement response 730 (e.g. block acknowledgement (BA) or an acknowledgement (ACK)) based on successfully receiving, via a spatial wireless channel, a VHT -Data segment 720a, which can include a MAC header and a MAC payload.
• An AP can transmit a block acknowledgement request (BAR) 740 to a second client (e.g., STA 2).
• BA block acknowledgement
• ACK acknowledgement request
• the second client Based on the BAR 740 and successfully receiving, via a spatial wireless channel, a VHT-Data segment 720b, which can include a MAC header and a MAC payload, the second client sends an acknowledgement response such as a block acknowledgement 750.
• an acknowledgement response such as a block acknowledgement 750.
• an AP can initiate a BA with multiple Block ACK capable SDMA clients by using an Add Block Acknowledgement (ADDBA) request and response exchange.
• ADDBA Add Block Acknowledgement
• a wireless communication system can use BA for acknowledgement of one or more received MPDUs.
• a BA agreement setup and BA management can be required.
• a BA queue is used for an active BA stream.
• a scoreboard and reordering buffer are used for an active BA stream.
• communication system can provide one or more mechanisms to reduce BA overhead for frames such as management frames and A-MPDUs with a single MPDU.
• FIG. 8A shows an example of communication flow layout associated with reduced BA overhead.
• a VHT device can transmit two or more VHT A-MPDUs to two or more respective VHT devices via two or more spatial wireless channels.
• a VHT-SIG 815a, 815b can include a field that indicates whether a VHT A- MPDU is an A-MPDU with a single MPDU (SM-A-MPDU).
• some implementations can configure a device to detect a SM-A-MPDU based on a lack of detecting a delimiter before detecting a MAC pad.
• FIG. 8B shows an example of an A-MPDU layout associated with reduced BA overhead.
• a device includes one or more null subframes 845, such as an EOF padding delimiter, after a single A-MPDU subframe 835 to indicate that the A-MPDU 830 has a single non-zero length MPDU (e.g., SM-A-MPDU).
• the device can include a first MAC pad 840 after the A-MPDU subframe 835 to make the A-MPDU subframe 835 reach a 32-bit boundary and before the one or more null subframes 845, e.g., padding delimiters.
• the device can include a second MAC pad 841 after the one or more null subframes 845.
• the MAC pads 840, 841 if present, can be 1, 2, or 3 octets in length.
• MAC layer padding can include the first and second MAC pads 840, 814, and the one or more null subframes 845.
• FIG. 8C shows an example of an A-MPDU subframe layout associated with reduced BA overhead.
• A-MPDU subframe 850 can include signaling to indicate that the A-MPDU 830 has a single MPDU (e.g., SM-A-MPDU).
• SM-A-MPDU e.g., SM-A-MPDU
• SM-A-MPDU signaling uses a 1-bit field in a leading field 855 of an A-MPDU subframe 850.
• SM-A-MPDU signaling can reuse the EOF bit in the delimiter to indicate that an A-MPDU is a SM-A-MPDU, with the EOF flag being set to 1 and the MPDU length being greater than 0.
• SM-A-MPDU signaling uses a delimiter signature 860.
• SM-A-MPDU signaling uses a subfield in a MAC header 865 to indicate a SM-A-MPDU.
• a SM-A-MPDU can be transmitted without a previously established BA agreement, e.g., an ADDBA exchange is not required. Queues other than BA queues can be used to buffer SM-A-MPDUs.
• An acknowledgement policy of a SM-A-MPDU can be set as Normal ACK.
• a SM-A-MPDU can be accepted without an associated and active BA stream. Scoreboard and BA reorder buffering are not required for a SM-A-MPDU requesting Normal ACK. Based on successfully receiving a SM-A-MPDU requesting Normal ACK, an ACK can be transmitted.
• FIG. 9A shows an example of a multi-user frame transmission layout and associated acknowledgement responses. In this example, only one SM-A-MPDU 905 is included in a multi-user (MU) frame 910 transmission.
• MU multi-user
• the SM-A-MPDU 905 can be a management A-MPDU frame.
• the MU frame 910 can include two or more A-MPDUs with multiple MPDUs (MM-A-MPDUs 915a, 915b).
• the SM-A-MPDU 905 indicates a request for a single acknowledgement, instead of a BA. Therefore, the SM-A-MPDU's ACK 925 cannot be polled by a BAR frame.
• the recipient of the SM-A-MPDU 905 can transmit an ACK 925 immediately after a SIFS duration from the MU frame 910 without explicit polling.
• a MU frame 910 can include at most one SM-A-MPDU 905 because only one recipient can transmit immediately after the MU frame 910.
• the recipients of the respective BAR frames 920a, 930b can transmit BAs 935a, 935b for respective MM-A- MPDUs 915a, 915b.
• the recipients of the MM-A-MPDUs 915a, 915b can transmit respective BAs 935a, 935b based on a MU response schedule after the
• a poll frame can be used to poll a single acknowledgement from a recipient of the SM-A-MPDU 905 after the MU frame 910.
• An Immediate Response Request (IRR) frame can be used to poll
• FIG. 9B shows a different example of a multi-user frame transmission layout and associated acknowledgement responses.
• two or more SM-A-MPDUs 955, 960 are included in a MU frame 970.
• the MU frame 970 can include one or more MM- A-MPDUs 965.
• An IRR frame 985a, 985b can be transmitted to poll immediate ACKs 990a, 990b from devices receiving the SM-A-MPDUs 955, 960.
• the recipients of SM-A-MPDUs 955, 960 do not send an ACK based on a SIFS duration after the MU frame.
• a BAR frame 975 can be transmitted to poll a BA 980 from a device receiving the MM-A- MPDU 965.
• Response types such as scheduled or sequential response can be used, e.g., a device receiving a SM-A-MPDU can send an ACK based on response schedules or sequences.
• FIG. 10 shows another example of a spatial communication flow layout.
• a device can add a PHY pad 1010 to a PPDU to ensure that PPDUs, in a SDMA transmission 1005, have the same duration (e.g., the same number of symbols).
• the device can add the PHY pad 1010 to extend PHY data to the end of the last symbol boundary.
• L-SIG 1020 length and rate fields can be used to indicate the common end (e.g. the number of symbols from the end of the L-SIG 1020 to the end of the PPDUs) of a group of PPDUs in the SDMA transmission 1005.
• a steered VHT-SIG 1050a, 1050b can be set based on a size of a corresponding PSDU to assist a receiving device to determine the end of the PSDU and remove the PHY pad 1010. Based on the PSDU length, the receiving device can stop receiving at the end of the PSDU and disregard the remaining PHY pad 1010 to save power. Note that in this case, the PSDU includes the useful data, and is not required to include a MAC pad.
• the PHY pad 1010 covers the remaining available bits, exclusive of the tail bits, in the PPDU till the end of the last symbol boundary.
• the tail bits (not shown) are appended. In some implementations, tail bits can be added after the PSDU and before PHY pad.
• Length and duration information of steered data units can be included in one or more fields of a SDMA transmission 1005.
• a steered VHT-SIG 1050a, 1050b field can include a field for the number of 4-octets of a steered PSDU, a field for the number of symbols of the steered PSDU, or both.
• a service field can include a field for the number of octets of a steered PSDU, a field for the number of 4-octets of the steered PSDU, a field for the number of symbols of the steered PSDU, or a
• An extended service field includes a field for the number of octets of a steered PSDU, a field for the number of 4-octets of the steered PSDU, a field for the number of symbols of the steered PSDU, or a combination thereof.
• the service field can include a checksum to protect against signal corruption and can include a full or partial destination address (e.g., AID, MAC address, or BSSID) for a receiving device to decide whether to process the remaining frame.
• length and duration information of steered data units can be included in a MAC frame element such as a MAC header, a delimiter, or a MPDU subframe.
• one or more PSDUs, in a MU frame can be padded to a 4-octet boundary.
• the steered PSDU length indicates the PSDU 4-octet boundary.
• a receiver decodes until a PSDU's 4-octet boundary and stops receiving the MU frame.
• An A-MPDU format can be used, and the last A-MPDU subframe can be padded to a 4-octet boundary.
• the PSDU Based on a PSDU with a Qword pad not exceeding the last symbol, the PSDU can be padded to a 4-octet boundary, which is indicated by the steered PSDU length field.
• the PSDU can be padded to the last octet; however, the steered PSDU length indicates the PSDU length plus the Qword pad.
• a recipient device can detect that a PSDU is padded to the last octet when finding that the steered PSDU length exceeds the last symbol boundary.
• a steered data unit length indicates a length of a PSDU plus Qword pad.
• a steered data unit length indicates a position of the last 4-octet boundary.
• FIG. 1 1 shows another example of a spatial communication flow layout.
• a steered VHT-SIG field 1 105 can indicate the end of useful data in a corresponding PSDU (e.g., end of useful data in an A-MPDU). After the end of useful data in a PSDU, there can be padding such as a MAC pad, PHY pad, or both.
• a steered VHT- SIG field 1 105 includes the length (e.g., number of octets, or number of 4-octets) of useful data in a corresponding PSDU.
• a steered VHT-SIG field 1 105 includes the duration (e.g.
• the L-SIG 11 10 can include a length field, a rate field, or both to indicate the duration of a PPDU.
• multiple PPDUs have the same ending point, which is indicated by the L-SIG 11 10.
• a length field can be included in a steered VHT-SIG 1105 to indicate the number of octets or number of 4-octets of useful data included in a corresponding PSDU, exclusive of the padding and tail bits. Based on the length field, a receiving device can stop receiving at the end of the indicated useful data to save power and disregard the remaining data. In some implementations that are based on a length that represents the number of 4- octets, the length may indicate a 4-octet boundary which exceeds the last symbol boundary; in this case, a receiving device processes till the last byte of a PPDU and discards the remaining data such as a PHY pad and tail bits.
• a duration field can be included in a steered VHT-
• SIG 1 105 to indicate the number of symbols required to cover the useful data in a corresponding PSDU. Based on this duration field, the receiving PHY can stop receiving at the end of the indicated duration and discard the remaining data.
• the receiving MAC can determine the end of the useful data based on the last A-MPDU subframe passed from the receiving PHY. In some implementations, a receiving MAC can determine the end of the useful data based on a detected EOF padding delimiter.
• data processing apparatus encompasses all apparatus, devices, and machines for processing data, including by way of example a programmable processor, a computer, or multiple processors or computers.
• the apparatus can include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of them.
• a program (also known as a computer program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, or declarative or procedural languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.
• a program does not necessarily correspond to a file in a file system.
• a program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more modules, sub programs, or portions of code).
• a program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network.

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