Patent Publication Number: US-10334476-B2

Title: Single MPDU frame signaling

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of, claims the benefit of and priority to, previously filed U.S. patent application Ser. No. 14/987,706 filed on Jan. 4, 2016, which is a continuation of U.S. patent application Ser. No. 14/055,804 filed on Oct. 16, 2013, entitled “SINGLE MPDU FRAME SIGNALING”, which is a continuation of previously filed U.S. patent application Ser. No. 12/977,522 filed on Dec. 23, 2010, and subsequently issued as U.S. Pat. No. 8,665,843 on Mar. 4, 2014; the subject matter of all of the above is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This application relates to wireless systems and, more particularly, to systems and methods for media access control (MAC) protocol data unit (MPDU) signaling in a wireless environment. 
     BACKGROUND 
     An increased throughput, e.g., above 1 Gigabit-per-second (Gbps) per wireless communication can be necessary to transfer data within wireless communication networks, such as, for example, wireless local area networks (WLAN) and/or wireless personal area networks (WPAN). The increased throughput may be achieved by using a communication link having a wide bandwidth. For example, a bandwidth of 80 Mega-Hertz (MHz) or more may be required to provide a throughput greater than 1 Gbps, e.g., in a network operating over a frequency band of 5 Giga-Hertz (GHz) in accordance with the IEEE 802.11 standards. 
     Increased throughput may also be supported by reducing signaling requirements and decreasing an amount of overhead used for the transmission and reception of data in the wireless communication network. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is illustrated by way of example and not as a limitation in the figures of the accompanying drawings, in which: 
         FIG. 1  is an schematic block diagram illustration of neighboring wireless communication networks, in accordance with some demonstrative embodiments; 
         FIG. 2  is a schematic block diagram illustration of a system, in accordance with some demonstrative embodiments; 
         FIG. 3  is a block diagram illustration of an aggregate MPDU (A-MPDU) frame structure, in accordance with some demonstrative embodiments; 
         FIG. 4  is a block diagram illustration of an A-MPDU frame comprising multiple MPDUs, in accordance with some demonstrative embodiments; 
         FIG. 5  is a block diagram illustration of an A-MPDU frame comprising a single MPDU, in accordance with some demonstrative embodiments; and 
         FIG. 6  is a block diagram illustration of methods for single MPDU frame signaling, in accordance with some demonstrative embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, numerous specific details are set forth to provide a thorough understanding of embodiments of the invention. However it will be understood by those skilled in the art that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure embodiments of the invention. 
     Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as “processing,” “computing,” “calculating,” “determining,” “selecting,” “decoding,” or the like, may refer to the action and/or processes of a computer or computing system, or similar electronic computing device, that manipulate and/or transform data represented as physical, such as electronic, quantities within the computing system&#39;s registers and/or memories into other data similarly represented as physical quantities within the computing system&#39;s memories, registers or other such information storage, transmission or display devices. In addition, the term “plurality” may be used throughout the specification to describe two or more components, devices, elements, parameters and the like. Furthermore, the term “and/or” may mean “and”, it may mean “or”, it may mean “exclusive-or”, it may mean “one”, it may mean “some, but not all”, it may mean “neither”, and/or it may mean “both”, although the scope of claimed subject matter is not limited in this respect. 
     The following detailed description describes various embodiments for communicating over a number of channels in wireless networks to communicate packets, such as Physical Layer Convergence Protocol (PLCP) protocol data units (PPDUs) using a wireless device, platform, user equipment (UE), station (STA), subscriber station (SS), mobile station (MS), advanced mobile station (AMS), high throughput (HT) station (STA), or very HT STA (VHT STA). The various forms of devices described above such as the platform, UE, SS, MS, HT STA, and VHT STA may be interchanged and reference to a particular device does not preclude other devices from being substituted in various embodiment(s). The device may communicate in a network with one or more other devices such as a base station (BS), access point (AP), node, node B, or enhanced node B (eNB). Further, these terms may be conceptually interchanged, depending on which wireless protocol is being used in a particular wireless network, so a reference to BS herein may also be seen as a reference to either of ABS, eNB, or AP as one example. Similarly, a reference to a STA or MS herein may also be seen as a reference to either of HT STA, VHT STA, or SS as another example. Reference to a particular device does not preclude other devices from being substituted in various embodiment(s). 
     Some embodiments may be used in conjunction with various fixed and/or mobile devices, for example, a Personal Computer (PC), a desktop computer, a mobile computer, a laptop computer, a notebook computer, a tablet computer, a server computer, a handheld computer, a handheld device, a Personal Digital Assistant (PDA) device, a handheld PDA device, an onboard device, an off-board device, a hybrid device, and a vehicular device. 
     Further, embodiments of the invention may be used in one or more wired or wireless networks, a wireless area network, a Wireless Video Area Network (WVAN), a Local Area Network (LAN), a Wireless LAN (WLAN), a Wireless Metropolitan Area Network (WMAN) communication system, a Personal Area Network (PAN), a Wireless PAN (WPAN), devices and/or networks operating in accordance with existing IEEE 802.11 (IEEE Standard for Information technology—Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific requirements, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications—June 2007), 802.11n, 802.11 task group ac (TGac), 802.11ac, 802.11 task group ad (TGad) (“the 802.11 standards”), 802.16 (IEEE-Std 802.16, 2004 Edition, Air Interface for Fixed Broadband Wireless Access Systems), 802.16d, 802.16e (IEEE-Std 802.16e, 2005 Edition, Physical and Medium Access Control Layers for Combined Fixed and Mobile Operation in Licensed Bands), 802.16f, 802.16m standards (“the 802.16 standards”) and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing Wireless-Gigabit-Alliance (WGA) and/or WirelessHDTM specifications and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing cellular specifications and/or protocols, e.g., 3rd Generation Partnership Project (3GPP), 3GPP Long Term Evolution (LTE), and/or future versions and/or derivatives thereof, units and/or devices which are part of the above networks. 
     In the field of communications, including wireless communications, it would be helpful to provide devices and methods for the use of wideband transmissions in wireless environments, wherein the wideband transmissions use reduced overhead signaling to enable more efficient transmission of data in the wireless environment. As an example, wireless communications using IEEE 802.11n as the communications protocol includes a frame that is formatted with an aggregate bit in a HT-signal (SIG) field set to 0 (zero), wherein the frame comprises a single MPDU. Alternately, the 802.11n protocol also includes a frame that is formatted with the aggregate bit in the HT-SIG field set to one which carries an A-MPDU payload comprising a number of MPDUs. The format differences in the frames of 802.11n affect acknowledgement rules, wherein a quality of service (QoS) data MPDU with an acknowledgment (Ack) policy field set to “normal Ack” solicits an Ack response if the MPDU is carried in a frame with the aggregate bit set to 0 (zero), but solicits a block Ack (BA) response if the MPDU is carried in a frame with the aggregate bit set to one. 
     The use of a separate bit to prompt an acknowledgement type in response to a transmission can impact space limitations within the transmission, thereby making it undesirable to add a bit to prompt a desired response behavior. It would be helpful to prompt a desired response or acknowledgement behavior without using an additional bit, such as by implementing a signaling protocol based at least in part on a structure of a frame. In embodiments, a signaling method is proposed for signaling that a single MPDU is carried in an A-MPDU, as indicated by a frame structure or frame characteristics. The signaling method can then be used to solicit or prompt a desired acknowledgement behavior. 
     Turning now to the figures,  FIG. 1  illustrates neighboring wireless communication networks in accordance with some embodiments. The neighboring wireless communication networks include two or more basic service sets (BSS), such as very-high throughput (VHT) BSS  100  and high-throughput (HT) BSS  110 . VHT BSS  100  may include VHT access point (AP)  104  and one or more VHT communication stations (STA)  102 , and HT BSS  110  may include neighboring HT AP  114  and one or more HT communication stations (STA)  112 . In an embodiment, VHT BSS  100  is configured to operate in accordance with IEEE 802.11ac and the HT BSS  110  is configured to operate in accordance with IEEE 802.11n. Other wireless protocols may be used in additional embodiments. 
     VHT BSS  100  may utilize a primary channel and up to three or more secondary channels. HT BSS  110 , on the other hand, may be limited to using a primary channel and a single secondary channel. In accordance with some embodiments, VHT communication station  102  may be configured to communicate a data unit, such as a physical layer convergence procedure (PLCP) protocol data unit (PPDU), on a primary channel and up to three or more secondary channels, and HT communication station  112  may be configured to communicate a PPDU on a primary channel and up to one secondary channel. 
     Reference is now made to  FIG. 2 , which schematically illustrates a block diagram of a system  200  in accordance with some demonstrative embodiments. In some demonstrative embodiments, system  200  may include one or more wireless communication devices, e.g., wireless communication devices  202  and/or  206 , capable of communicating content, data, information and/or signals over a wireless communication link  216 . One or more elements of system  200  may optionally be capable of communicating over any suitable wired communication links. 
     In some demonstrative embodiments, wireless communication devices  202  and/or  206  may include embodiments of the various devices described earlier including the VHT STA  102 , the VHT AP  104 , the HT STA  112 , and the HT AP  114 . In some demonstrative embodiments, device  202  may include a wireless communication unit  208  to transmit, via one or more antennae  212 , a wireless transmission to device  206  over wireless communication link  216 . Device  206  may include a wireless communication unit  240  to receive the wireless transmission via one or more antennae  214 . Types of antennae that may be used for antennae  212  and/or  214  may include but are not limited to internal antenna, dipole antenna, omni-directional antenna, a monopole antenna, an end fed antenna, a circularly polarized antenna, a micro-strip antenna, a diversity antenna and other antenna types known to one skilled in the art. 
     In some demonstrative embodiments, wireless communication devices  202  and/or  206  may also include, for example, one or more of a processor  226 , an input unit  218 , an output unit  220 , a memory unit  222 , and a storage unit  224 . Wireless communication devices  202  and/or  206  may optionally include other suitable hardware components and/or software components. In some demonstrative embodiments, some or all of the components of each of wireless communication devices  202  and/or  206  may be enclosed in a common housing or packaging, and may be interconnected or operably associated using one or more wired or wireless links. In other embodiments, components of each of wireless communication devices  202  and/or  206  may be distributed among multiple or separate devices. 
     Processor  226  includes, for example, a Central Processing Unit (CPU), a Digital Signal Processor (DSP), one or more processor cores, a single-core processor, a dual-core processor, a multiple-core processor, a microprocessor, a host processor, a controller, a plurality of processors or controllers, a chip, a microchip, one or more circuits, circuitry, a logic unit, an Integrated Circuit (IC), an Application-Specific IC (ASIC), or any other suitable multi-purpose or specific processor or controller. Processor  226  executes instructions, for example, of an Operating System (OS) of wireless communication devices  202  and/or  206  and/or of one or more suitable applications. 
     Input unit  218  includes, for example, a touchscreen, a keyboard, a keypad, a mouse, a touch-pad, a track-ball, a stylus, a microphone, or other suitable pointing device or input device. Output unit  220  includes, for example, an audio system and/or a video display. 
     Memory unit  222  includes, for example, a Random Access Memory (RAM), a Read Only Memory (ROM), a Dynamic RAM (DRAM), a Synchronous DRAM (SD-RAM), a flash memory, a volatile memory, a non-volatile memory, a cache memory, a buffer, a short term memory unit, a long term memory unit, or other suitable memory units. Storage unit  224  includes, for example, a hard disk drive, a floppy disk drive, a Compact Disk (CD) drive, a CD-ROM drive, a DVD drive, or other suitable removable or non-removable storage units. Memory unit  222  and/or storage unit  224 , for example, may store data processed by wireless communication device  202  and/or  206 . 
     In some demonstrative embodiments, wireless communication unit  208  may include a plurality of transmit (Tx) chains  211  to transmit the wireless transmission over the plurality of wireless communication channels. Wireless communication unit  240  may include a plurality of receive (Rx) chains  244  to receive the wireless transmission over the plurality of wireless communication channels. In some demonstrative embodiments, Tx chains  211  and/or Rx chains  244  may include any suitable Physical-layer (PHY) chains and/or components; any suitable Radio-Frequency (RF) chains and/or components; and/or any other suitable elements. 
     In some demonstrative embodiments, wireless communication unit  208  may include a media-access-controller (MAC)  210 , e.g., a single MAC, to commonly control the transmissions via Tx chains  211 ; and/or wireless communication unit  240  may include a MAC  242 , e.g., a single MAC, to commonly control the reception via Rx chains  244 , e.g., as described in detail below. 
     In some demonstrative embodiments, MAC  210  may control Tx chains  211  to simultaneously transmit symbols of a wireless communication packet over the number of wireless communication channels of wireless communication link  216 . MAC  242  may control Rx chains  244  to simultaneously receive the symbols of the wireless communication packet over the number of wireless communication channels of wireless communication link  216 . 
       FIG. 3  is a block diagram illustration of an A-MPDU  300  frame used, for example, in an 802.11ac communication link comprising a sequence of a number of A-MPDU subframes including A-MPDU subframe  1   302 , A-MPDU subframe  2   304 , through and including A-MPDU subframe n  306 , along with an end of frame (EOF) pad  308 . The number of subframes used in a particular communication is variable and can include one or more subframes per A-MPDU  300  frame. An aggregate bit is not needed to signal a format of a payload in the A-MPDU  300  frame that is consistent with an 802.11ac communications protocol. 
     The EOF pad  308  may contain bits to fill-out the A-MPDU  300  frame, for example 0 to 3 octets in length, wherein each octet represents 8 bits. The A-MPDU subframe  1   302  is detailed further in  FIG. 3  to show a subframe structure, wherein in this embodiment the A-MPDU  302  comprises an MPDU delimiter  310 , an MPDU  312 , and a pad  314 . The A-MPDU  302  is illustrated having one MPDU  312 , however the embodiment is not so limited and alternately may contain none or more than one MPDU  312 . The MPDU  312  may comprise data having a variable length and may be subject to a maximum length measured in octets depending on applicable wireless protocol limitations. 
     The pad  314  is appended to the A-MPDU subframe  1   302  and is 0 to 3 octets in length in one embodiment. The pad  314  may contain additional octects or the A-MPDU subframe  1   302  may not comprise a pad  314  in other embodiments. The MPDU delimiter  310  is also illustrated further to detail a delimiter structure, wherein in this embodiment the MPDU delimiter  310  comprises an EOF field  316 , a reserved field  318 , an MPDU length  320 , a cyclic redundancy check (CRC) field  322 , and a delimiter signature  324 . 
     The EOF field  316  is an indication field that may contain a number of bits, wherein in an embodiment a bit is set to 1 (one) in all zero length A-MPDU subframes following a last non-zero length A-MPDU subframe in a VHT PPDU. The EOF field  316  may be set to 1 (one) in a single A-MPDU subframe such as A-MPDU subframe  1   320  in an embodiment having a non-zero length. The EOF field  316  is set to 0 (zero) otherwise. The reserved field  318  is left available for a number of bits to indicate a status or for signaling purposes. The MPDU length  320  indicates a length of the MPDU  312 , wherein the length may be expressed in octets and may be 14 bits in length, wherein a number of the 14 bits may be high order bits and a number of the 14 bits are low order bits in an embodiment. The CRC field  322  is a field having a length in bits, such as 8 bits, to provide a CRC 322 of one or more preceding bits. The delimiter signature  324  in an embodiment is a pattern, which may be a unique pattern that can be used to detect an MPDU delimiter  310 , such as when a wireless communication device  202  is scanning for an MPDU delimiter  310 . 
       FIG. 4  is a block diagram illustration of an A-MPDU frame  300  comprising multiple MPDUs  312  of  FIG. 3 , in accordance with some demonstrative embodiments. An A-MPDU  300 , described earlier in embodiments in reference to  FIG. 3 , comprises a number of MPDUs  312  and MPDU delimiters  310 . The A-MPDU  300  of  FIG. 4  comprises MPDU  404  and MPDU  412 , an EOF pad  420 , and a plurality of MPDU delimiters  310 . Delimiter  402  is followed by MPDU  404 , so the delimiter  402  is configured with the MPDU length  320  greater than 0 (zero) to signal the payload of MPDU  404 , and the EOF field  316  in the delimiter  402  is set to 0 (zero). The MPDU  404  is followed by delimiters  406 ,  408  and  410 . As an example, delimiter  408  is configured with the MPDU length  320  set to 0 (zero) since the delimiter  408  is followed by another delimiter  410 , and the EOF field  316  in delimiter  408  is also set to 0 (zero). MPDU  412  is followed by delimiters  414 ,  416 , and  418  wherein delimiter  416  and delimiter  418  is, for example, configured with the MPDU length  320  set to 0 (zero) and the EOF field  316  set to 1 (one). 
       FIG. 5  is a block diagram illustration of an A-MPDU frame comprising a single MPDU  312 , in accordance with some demonstrative embodiments. The A-MPDU  300  in these embodiments comprise a single MPDU  312 , a plurality of MPDU delimiters  310 , and an EOF pad  512  as described in reference to  FIG. 3 . Delimiter  502  is followed by a single MPDU  504  in the A-MPDU  300 , so the delimiter  502  is configured with the MPDU length  320  greater than 0 (zero) to signal the payload of MPDU  504  and the EOF field  316  set to 1 (one). The MPDU  504  is followed by delimiter  506 , delimiter  508  and delimiter  510 . As an example, delimiters  508  and  510  are configured with the MPDU length  320  set to 0 (zero) and the EOF field  316  is set to 1 (one). 
     As described in reference to  FIG. 5 , an A-MPDU  300  frame structure is provided to prompt or solicit a desired acknowledgement behavior from a receiver such as the wireless communication device  206  of  FIG. 2  based at least in-part on the frame structure. In embodiments, the EOF field  316  is used in combination with the MPDU length  320  to signal characteristics of the A-MPDU  300 , which may be used to solicit a desired acknowledgement behavior. 
     In an embodiment, when the EOF field  316  is set to 1 (one) and the MPDU length is greater than 0 (zero) in an MPDU delimiter  310  of delimiter  502 , this configuration is used to indicate that the A-MPDU  300  has only one MPDU  312  and that no other MPDUs  312  are present in the A-MPDU  300 . Further, where the EOF field  316  is set to 1 (one) and the MPDU length is greater than 0 (zero) in an MPDU delimiter  310 , wherein an Ack policy is set to “normal ack,” then an ACK response is expected from a receiving device such as the wireless communication device  206 . The MPDU  312  in this embodiment may be a quality of service (QoS) Data MPDU, however the embodiment is not so limited. In an alternate embodiment where the EOF field  316  is set to 0 (zero) and the MPDU length is greater than 0 (zero) in an MPDU delimiter  310 , wherein an Ack policy is set to “normal ack,” then a block Ack (BA) response is expected from the receiving device. 
     For the embodiment having the EOF field  316  is set to 1 (one) and the MPDU length is greater than 0 (zero) in an MPDU delimiter  310  to represent a single MPDU  312  in the A-MPDU  300 , the EOF field  316  in combination with MPDU length  320  greater than 0 (zero) structure is used to signal that there are no additional MPDUs  312  in the A-MPDU  300  frame. No additional signaling bits, such as aggregate bits, are necessary to indicate that A-MPDU  300  contains a single MPDU  312 . 
     In embodiments, the EOF field  316  can be established based on a number of criteria. For example, a padding delimiter is a delimiter with a length=0 (zero) and an EOF field  316  in a padding delimiter that occurs between MPDUs  312  can be set to 0 (zero). The EOF field  316  in a padding delimiter at the end of the A-MPDU  300 , following all MPDUs  312  in the A-MPDU  300 , can be set to 1 (one). Further an MPDU delimiter  310  that delimits, or immediately precedes an MPDU  312  has a length greater than 0 (zero) if the MPDU  312  is greater than 0 (zero). Also, for an A-MPDU  300  that has more than one MPDU  312 , delimiters that precede an MPDU  312  can have the EOF field  316  set to 0 (zero). For an A-MPDU  300  that carries a single MPDU  312 , an MPDU delimiter  310  in the A-MPDU  300  may have the EOF field  316  set to one. A transmitter such as the VHT AP  104  or the VHT communication station  102  of  FIG. 1  may set the EOF field  316  to 1 (one) to solicit an Ack response to a QoS data frame with an Ack policy equal to “normal ack.” The EOF field  316  may be set to 0 (zero) if a block acknowledgement (BA) response is expected. 
       FIG. 6  is a block diagram illustration of methods for single MPDU  312  frame signaling of an A-MPDU  300 , in accordance with some demonstrative embodiments. The methods include assembling the A-MPDU  300 , for example using a wireless communication unit  208 , by combining a single MPDU  312  with an MPDU delimiter  310  in element  602 , wherein the MPDU delimiter  310  comprises an end of frame (EOF) field  316  and a MPDU length  320  field, wherein the MPDU length is greater than zero. An EOF bit is set to one in the EOF field  316  in element  604 . The A-MPDU  300  is transmitted over an antenna  212  in element  606 . An acknowledgement (ACK) response is received in element  608  based at least in-part on a structure of the A-MPDU  300  frame, wherein the structure comprises an EOF field  316  set to one and an MPDU length  320  field having a length greater than zero. In these embodiments, an aggregate bit is not used to signal a format of the A-MPDU. 
     In some embodiments, the MPDU delimiter  310  may further comprise one or more of a reserved field  318 , a cyclic redundancy check  322  field, and a delimiter signature  324  field. Also, the single MPDU  312  may be a quality of service data MPDU with an acknowledgement policy set to normal acknowledgement and the A-MPDU  312  may be transmitted by a VHT STA  102  using an 802.11ac communication protocol in some embodiments. 
     The operations discussed herein may be generally facilitated via execution of appropriate firmware or software embodied as code instructions on tangible media as applicable. Thus, embodiments of the invention may include sets of instructions executed on some form of processing core or otherwise implemented or realized upon or within a machine-readable medium. A machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, a machine-readable medium can include an article of manufacture such as a read only memory (ROM); a random access memory (RAM); a magnetic disk storage media; an optical storage media; and a flash memory device, etc. In addition, a machine-readable medium may include propagated signals such as electrical, optical, acoustical or other form of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.). 
     While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within embodiments of the invention.