Patent Description:
In many telecommunication systems, 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). 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.).

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.

In order to address the issue of increasing bandwidth requirements that are demanded for wireless communications systems, different schemes are being developed to allow multiple user terminals to communicate with a single access point by sharing the channel resources while achieving high data throughputs, as for example described in <CIT>. However, with an increased amount of data transmitted to a user terminal, additional processing time may be necessary for the user terminal to adequately process the data it receives. Thus, there is a need for an improved protocol for single and multi-user signal extensions or padding.

The invention is solely defined by the claims and is disclosed in the embodiments related to <FIG>. Embodiments and aspects that do not fall within the scope of the claims are merely examples used for explanation of the invention. Wording such as "may" and "for example" used in the description in conjunction with features of the independent claims should not be interpreted to mean that those features are merely optional.

Various aspects of the novel systems, apparatuses, and methods are described more fully hereinafter with reference to the accompanying drawings. The teachings disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Based on the teachings herein one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the novel systems, apparatuses, and methods disclosed herein, whether implemented independently of or combined with any other aspect of the invention. In addition, the scope of the invention is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the invention set forth herein. It should be understood that any aspect disclosed herein may be embodied by one or more elements of a claim.

Although particular aspects are described herein, many variations and permutations of these aspects fall within the scope of the disclosure. Although some benefits and advantages of the preferred aspects are mentioned, the scope of the disclosure is not intended to be limited to particular benefits, uses, or objectives. Rather, aspects of the disclosure are intended to be broadly applicable to different wireless technologies, system configurations, networks, and transmission protocols, some of which are illustrated by way of example in the figures and in the following description of the preferred aspects. The detailed description and drawings are merely illustrative of the disclosure rather than limiting, the scope of the disclosure being defined by the appended claims and equivalents thereof.

Wireless network technologies may include various types of a wireless local area network (WLAN). 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 Institute of Electrical and Electronics Engineers (IEEE) <NUM> family of wireless protocols.

In some aspects, wireless signals may be transmitted according to a high-efficiency <NUM> protocol using orthogonal frequency-division multiplexing (OFDM), direct sequence spread spectrum (DSSS) communications, MIMO, some combination thereof, or other schemes. Implementations of the high-efficiency <NUM> protocol may be used for Internet access, sensors, metering, smart grid networks, or other wireless applications. Advantageously, 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.

In some implementations, a WLAN includes various devices which are the components that access the wireless network. For example, there may be two types of devices: access points ("APs") and clients (also referred to as stations, or "STAs"). In general, an AP serves as a hub or base station for the WLAN and an STA serves as a user of the WLAN. For example, a STA may be a laptop computer, a personal digital assistant (PDA), a mobile phone, etc. In an example, an STA connects to an AP via a Wi-Fi (e.g., IEEE <NUM> protocol such as <NUM>. 11ah) compliant wireless link to obtain general connectivity to the Internet or to other wide area networks. In some implementations an STA may also be used as an AP.

The teachings herein may be incorporated into (e.g., implemented within or performed by) a variety of wired or wireless apparatuses (e.g., nodes). In some aspects, a wireless node implemented in accordance with the teachings herein may comprise an access point or an access terminal.

An access point ("AP") may comprise, be implemented as, or known as a NodeB, Radio Network Controller ("RNC"), eNodeB, Base Station Controller ("BSC"), Base Transceiver Station ("BTS"), Base Station ("BS"), Transceiver Function ("TF"), Radio Router, Radio Transceiver, Basic Service Set ("BSS"), Extended Service Set ("ESS"), Radio Base Station ("RBS"), or some other terminology.

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. In some implementations 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. Accordingly, one or more aspects taught herein may be incorporated into a phone (e.g., a cellular phone or smartphone), a computer (e.g., a laptop), a portable communication device, 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), a gaming device or system, a global positioning system device, or any other suitable device that is configured to communicate via a wireless medium.

<FIG> is a diagram that illustrates a multiple-access multiple-input multiple-output (MIMO) system <NUM> with access points and user terminals. For simplicity, only one access point <NUM> is shown in <FIG>. An access point is generally a fixed station that communicates with the user terminals, and a user terminal or STA may be fixed or mobile, and may be referred to herein as simply a wireless communication device. The access point <NUM> may communicate with one or more wireless communication device <NUM> (illustrated as UTs 120a-i) at any given moment on the downlink and uplink. The downlink (i.e., forward link) is the communication link from the access point <NUM> to the wireless communication devices <NUM>, and the uplink (i.e., reverse link) is the communication link from the wireless communication devices <NUM> to the access point <NUM>. A wireless communication device <NUM> may also communicate peer-to-peer with another wireless communication device <NUM>. A system controller <NUM> couples to and provides coordination and control for the access points <NUM>.

While portions of the following disclosure will describe wireless communication device <NUM> capable of communicating via Spatial Division Multiple Access (SDMA), for certain aspects, the wireless communication devices <NUM> may also include some wireless communication devices <NUM> that do not support SDMA. Thus, for such aspects, the AP <NUM> may be configured to communicate with both SDMA and non-SDMA user terminals. This approach may conveniently allow older versions of wireless communication devices <NUM> ("legacy" stations) that do not support SDMA to remain deployed in an enterprise, extending their useful lifetime, while allowing newer SDMA wireless communication devices to be introduced as deemed appropriate.

The system <NUM> employs multiple transmit and multiple receive antennas for data transmission on the downlink and uplink. The access point <NUM> is equipped with Nap antennas and represents the multiple-input (MI) for downlink transmissions and the multiple-output (MO) for uplink transmissions. A set of K selected wireless communication devices <NUM> collectively represents the multiple-output for downlink transmissions and the multiple-input for uplink transmissions. For pure SDMA, it is desired to have Nap ≤ K ≤ <NUM> if the data symbol streams for the K wireless communication devices are not multiplexed in code, frequency or time by some means. K may be greater than Nap 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 wireless communication device may transmit user-specific data to and/or receive user-specific data from the access point. In general, each selected wireless communication device may be equipped with one or multiple antennas (i.e., Nut ≥ <NUM>). The K selected wireless communication devices can have the same number of antennas, or one or more wireless communication devices may have a different number of antennas.

The system <NUM> may be a SDMA system according to a time division duplex (TDD) or a frequency division duplex (FDD). For a TDD system, the downlink and uplink share the same frequency band. For an FDD system, the downlink and uplink use different frequency bands. The system <NUM> may also be a MIMO system utilizing a single carrier or multiple carriers for transmission. Each wireless communication device <NUM> 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 <NUM> may also be a TDMA system if the wireless communication devices <NUM> share the same frequency channel by dividing transmission/reception into different time slots, where each time slot may be assigned to a different wireless communication device <NUM>.

<FIG> illustrates a block diagram of the access point <NUM> and two wireless communication devices (illustrated as user terminal <NUM> and user terminal 120x) in system <NUM> (illustrated as a MIMO system). The access point <NUM> is equipped with Nt antennas 224a and 224ap. The user terminal <NUM> is equipped with Nut,m antennas 252ma and 252mu, and the user terminal 120x is equipped with Nut,x antennas 252xa and 252xu. The access point <NUM> is a transmitting entity for the downlink and a receiving entity for the uplink. The wireless communication devices <NUM> are transmitting entities for the uplink and a receiving entity for the downlink. As used herein, a "transmitting entity" is an independently operated apparatus or device capable of transmitting data via a wireless channel, and a "receiving entity" is an independently operated apparatus or device capable of receiving data via a wireless channel. In the following description, the subscript "dn" denotes the downlink, the subscript "up" denotes the uplink, Nup wireless communication devices <NUM> are selected for simultaneous transmission on the uplink, and Ndl wireless communication devices <NUM> are selected for simultaneous transmission on the downlink. Nup may or may not be equal to Ndn, and Nup and Ndn 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 <NUM> and/or the wireless communication devices <NUM>.

On the uplink, at each wireless communication device <NUM> selected for uplink transmission, a TX data processor <NUM> receives traffic data from a data source <NUM> and control data from a controller <NUM>. The TX data processor <NUM> processes (e.g., encodes, interleaves, and modulates) the traffic data for the wireless communication device <NUM> based on the coding and modulation schemes associated with the rate selected for the wireless communication device <NUM> and provides a data symbol stream. A TX spatial processor <NUM> performs spatial processing on the data symbol stream and provides Nut,m transmit symbol streams for the Nut,m antennas. Each transmitter unit <NUM> receives and processes (e.g., converts to analog, amplifies, filters, and frequency upconverts) a respective transmit symbol stream to generate an uplink signal. Nut,m transmitter/receiver units <NUM> provide Nut,m uplink signals for transmission from Nut,m antennas <NUM>, for example to transmit to the access point <NUM>.

Nup wireless communication devices <NUM> may be scheduled for simultaneous transmission on the uplink. Each of these wireless communication devices <NUM> 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 <NUM>.

At the access point <NUM>, Nup antennas 224a through 224ap receive the uplink signals from all Nup wireless communication device <NUM> transmitting on the uplink. Each antenna <NUM> provides a received signal to a respective receiver unit <NUM>. Each transmitter/receiver unit <NUM> performs processing complementary to that performed by transmitter/receiver unit <NUM> and provides a received symbol stream. A receive spatial processor <NUM> performs receiver spatial processing on the Nup received symbol streams from Nup transmitter/receiver units <NUM> and provides Nup 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. A receive data processor <NUM> 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 wireless communication device <NUM> may be provided to a data sink <NUM> for storage and/or a controller <NUM> for further processing.

On the downlink, at the access point <NUM>, a TX data processor <NUM> receives traffic data from a data source <NUM> for Ndn wireless communication devices <NUM> scheduled for downlink transmission, control data from a controller <NUM>, and possibly other data from a scheduler <NUM>. The various types of data may be sent on different transport channels. TX data processor <NUM> processes (e.g., encodes, interleaves, and modulates) the traffic data for each wireless communication device <NUM> based on the rate selected for that wireless communication device <NUM>. The TX data processor <NUM> provides Ndn downlink data symbol streams for the Ndn wireless communication devices <NUM>. A TX spatial processor <NUM> performs spatial processing (such as a precoding or beamforming) on the Ndn downlink data symbol streams, and provides Nup transmit symbol streams for the Nup antennas. Each transmitter/receiver unit <NUM> receives and processes a respective transmit symbol stream to generate a downlink signal. Nup transmitter/receiver units <NUM> may provide Nup downlink signals for transmission from Nup antennas <NUM>, for example to transmit to the wireless communication devices <NUM>.

At each wireless communication device <NUM>, Nut,m antennas <NUM> receive the Nup downlink signals from the access point <NUM>. Each transmitter/receiver unit <NUM> processes a received signal from an associated antenna <NUM> and provides a received symbol stream. An receive spatial processor <NUM> performs receiver spatial processing on Nut,m received symbol streams from Nut,m transmitter/receiver units <NUM> and provides a recovered downlink data symbol stream for the wireless communication device <NUM>. The receiver spatial processing may be performed in accordance with the CCMI, MMSE, or some other technique. A receive data processor <NUM> processes (e.g., demodulates, deinterleaves and decodes) the recovered downlink data symbol stream to obtain decoded data for the wireless communication device <NUM>.

At each wireless communication device <NUM>, a channel estimator <NUM> estimates the downlink channel response and provides downlink channel estimates, which may include channel gain estimates, signal to noise ratio (SNR) estimates, noise variance and so on. Similarly, a channel estimator <NUM> estimates the uplink channel response and provides uplink channel estimates. Controller <NUM> for each user terminal typically derives the spatial filter matrix for the wireless communication device <NUM> based on the downlink channel response matrix Hdn,m for that wireless communication device <NUM>. Controller <NUM> derives the spatial filter matrix for the access point <NUM> based on the effective uplink channel response matrix Hup,eff. The controller <NUM> for each wireless communication device <NUM> may send feedback information (e.g., the downlink and/or uplink eigenvectors, eigenvalues, SNR estimates, and so on) to the access point <NUM>. The controllers <NUM> and <NUM> may also control the operation of various processing units at the access point <NUM> and wireless communication devices <NUM>, respectively.

<FIG> illustrates various components that may be utilized in a wireless communication device <NUM> that may be employed within the wireless communication system <NUM>. The wireless communication device <NUM> is an example of a device that may be configured to implement the various methods described herein. The wireless communication device <NUM> may implement an access point <NUM> or a wireless communication device <NUM>.

The wireless communication device <NUM> may include an electronic hardware processor <NUM> which controls operation of the wireless communication device <NUM>. The processor <NUM> may also be referred to as a central processing unit (CPU). Memory <NUM>, which may include both read-only memory (ROM) and random access memory (RAM), provides instructions and data to the processor <NUM>. A portion of the memory <NUM> may also include non-volatile random access memory (NVRAM). The processor <NUM> may perform logical and arithmetic operations based on program instructions stored within the memory <NUM>. The instructions in the memory <NUM> may be executable to implement the methods described herein.

The processor <NUM> 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 wireless communication device <NUM> may also include a housing <NUM> that may include a transmitter <NUM> and a receiver <NUM> to allow transmission and reception of data between the wireless communication device <NUM> and a remote location. The transmitter <NUM> and receiver <NUM> may be combined into a transceiver <NUM>. A single or a plurality of transceiver antennas <NUM> may be attached to the housing <NUM> and electrically coupled to the transceiver <NUM>. The wireless communication device <NUM> may also include (not shown) multiple transmitters, multiple receivers, and multiple transceivers.

The wireless communication device <NUM> may also include a signal detector <NUM> that may be used in an effort to detect and quantify the level of signals received by the transceiver <NUM>. The signal detector <NUM> may detect such signals as total energy, energy per subcarrier per symbol, power spectral density and other signals. The wireless communication device <NUM> may also include a digital signal processor (DSP) <NUM> for use in processing signals.

The various components of the wireless communication device <NUM> may be coupled together by a bus system <NUM>, which may include a power bus, a control signal bus, and a status signal bus in addition to a data bus.

Certain aspects of the present disclosure support transmitting data packets from multiple STAs to an AP. In some embodiments, the data packets may be transmitted in a multi-user MIMO (MU-MIMO) system. Alternatively, the data packets may be transmitted in a multi-user-FDMA (MU-FDMA), multi-user OFDMA (MU-OFDMA) or similar Frequency Division Multiple Access (FDMA) system. In these embodiments, uplink MU-MIMO, uplink OFDMA, or similar uplink FDMA system transmissions can be sent simultaneously from multiple STAs to an AP and may create efficiencies in wireless communication.

<FIG> illustrates an exemplary data packet <NUM>, in accordance with one embodiment. In some aspects, one or more of the wireless communication devices <NUM> may transmit data packet <NUM> to AP <NUM>. In some aspects, AP <NUM> may transmit data packet <NUM> to one or more of the wireless communication devices <NUM>. In various aspects, data packet <NUM> is transmitted over a plurality of symbols. The number of symbols used to transmit data packet <NUM> can vary greatly depending on the contents thereof. As illustrated, data packet <NUM> comprises legacy preamble <NUM>, high efficiency (HE) preamble <NUM>, and HE data <NUM> through <NUM>.

In various aspects, data packet <NUM> may include data transmitted in accordance with an IEEE <NUM>. 11ax format. In accordance with these aspects, the amount of information transmitted in data packet <NUM> can be approximately four times more than the information transmitted in accordance with other protocols (e.g., <NUM>. In various embodiments, multiple data packets <NUM> may be transmitted in series to a receiving device (e.g., wireless communication device <NUM> or AP <NUM>). In accordance with these embodiments, there may only be a SIFS (Short Interframe Space) between consecutive transmissions of the multiple data packets <NUM>. However, a SIFS time period between packets may not be a sufficient amount of processing time for a device receiving the packet <NUM> to completely process the packet before a second packet arrived. This may especially be the case when the packet <NUM> has four times the information than, for example, an <NUM>. 11a packet. Accordingly, various systems and methods for providing the receiving device with additional processing time are described.

<FIG> illustrates various final symbols with signal extension (SE) of an exemplary data packet, in accordance with one embodiment. In some aspects, a transmitting device (e.g., wireless communication device <NUM> or AP <NUM>) may append a SE to the end of the final symbol of a data transmission to afford a receiving device with additional processing time. If a receiving device is not receiving any "useful" information in at least a portion of the final symbol of a data transmission, the receiving device is not required to process those bits that are not "useful". This enables the receiver to process a smaller number of bits in the last symbol which can be completed in a smaller amount of time (within SIFS+the signaling extension (SE) time when the SE is added to the last symbol or within SIFS alone if SE is not added).

Useful bits may include, for example, data bits encoding user data included in the data packet, and, in some aspects, bits necessary to properly decode the data bits from the packet. In some aspects, useful bits may be a first type of bits, while other bits may be a second type of bits. In some aspects, useful bits may be bits associated with a first layer in a layered protocol architecture. For example, in some aspects using <NUM>, the <NUM> protocol may utilize one or more bits in each packet for signaling purposes. Other bits in a packet may be provided by a higher layer, for example, an application layer. In some aspects, the bits provided by the higher layer, i.e. above the <NUM> layer, may be considered useful bits. These higher layer bits may be considered a first type of bits, while bits utilized for <NUM> signaling may be considered a second type of bits. In some aspects, useful bits may be utilized for encoding data bits received from a higher level protocol or application layer.

Accordingly, in some aspects the amount, length, or size of the SE can depend on how much information is remaining (also referred to as "excess") in the final symbol. In various aspects, four different sizes of SE may be used based on how much information is remaining in the final symbol. In some aspects, each size may correspond to a percentage (e.g., <NUM>%, <NUM>%, <NUM>%, <NUM>%), but may be represented by an integer (e.g., <NUM>-<NUM>) or a two bit indication (e.g., <NUM>, <NUM>, <NUM>, or <NUM>). In accordance with these aspects, various cut-offs may be utilized (also referred to as "a," the "a factor," or the "a value") by the transmitting and receiving devices. For example, "a = <NUM>" may refer to the first quarter of the final symbol, "a = <NUM>" may refer to the second quarter of the final symbol, "a = <NUM>" may refer to the third quarter of the final symbol, and "a = <NUM>" may refer to the fourth quarter of the final symbol. Although four values for the a value are discussed herein, it will be appreciated that other numbers may be used. In some aspects, the a value may refer to a fraction of "useful bits" in the final symbol of the data transmission (e.g., an a value of <NUM> can indicate that the first quarter of bits convey information to the receiving device, and an a value of <NUM> can indicate that the first half of the bits convey information that may be used by the receiving device).

In various aspects, a device transmitting this data may be able to determine the length of the excess information bits in the final symbol, and in turn, what value 'a' to include in a packet, a priori, based on information about the entire transmission (e.g., data packet <NUM>). Thereafter, a device receiving this data may be able to determine what a value to use based on information about the data (e.g., the length of the packet).

Illustrated in <FIG>, packet 512a is shown with a = <NUM>. Packet 512a includes excess information bits 502a remaining within the first quarter of the final symbol 510a of packet 512a. In some aspects, a transmitting device may add pre-FEC (frame-error checking) padding bits 504a up to the boundary corresponding to the first quarter (<NUM>%) of the symbol 510a. When processing the symbol 510a, a receiving device may only process the bits untilthe end of pre-FEC padding bits 504a. Thus, bits included in the Post-FEC padding field 506a and the SE1 field 508a may be received but not processed by a device receiving the packet 512a.

In some aspects, a transmitting device may add post-FEC padding bits 506a at the end of the symbol 510a, in some cases after pre-FEC padding bits, and may add SE 508a of a first length to the end of the packet 512a. In accordance with these aspects, a receiving device may use the time corresponding to the time it would normally require to process received bits, to instead of processing or decoding the post-FEC padding bits 506a and SE 508a, the device may process the other information received in the packet 512a. After a SIFS time period after the end of the symbol 510a and SE 508a have been transmitted, a transmitting device of packet 512a may transmit another data packet.

Packet 512b may include SE 508b of a second length when a = <NUM> (excess info bits 502b within the first half of symbol 510b). Packet 512b may also be generated to include Pre-FEC padding bits 504b and Post-FEC Padding Bits 506b within the symbol 510b. Note <FIG> not to scale.

Turning to <FIG>, packet 512c may include SE 508c of a third length when a = <NUM> (excess info bits 502c within the first three quarters of symbol 510c). Packet 512c may also be generated to include Pre-FEC padding bits 504c and Post-FEC Padding Bits 506c within the symbol 510c.

Packet 512d may include SE 508d of a fourth length when a = <NUM> (excess info bits 502d within all four quarters of symbol 510d). Packet 512d may include pre-FEC padding bits 504d and post-FEC-padding bits 506d within the symbol 510d. In various aspects, the first length may be <NUM>, the second length may be <NUM>, the third length may be <NUM>, and the fourth length may be <NUM>. In some aspects, one or more of packets 512a-d may not include SE field 508a-d.

<FIG> illustrates an exemplary transmission of a data packet <NUM> with SE, in accordance with one embodiment of the claimed invention. As illustrated, packet <NUM> comprises a legacy preamble and HE preamble <NUM>, HE data <NUM>-N transmitted over a plurality of symbols <NUM>, and SE <NUM> appended to the end. Each of the individual symbols within <NUM> has a data symbol duration (not shown). In some aspects, a device receiving packet <NUM> may calculate the number of symbols required to receive the packet <NUM>, based at least in part upon a transmission length.

In some aspects, a transmission length of the packet <NUM> is provided in the legacy preamble or the HE preamble <NUM>. However, a quantization of the transmission length may create ambiguities due to a "rounding error" Δ. Accordingly, in various aspects, a transmitting or receiving device may determine that an applied SE will cause processing inefficiencies based on the rounding error Δ. For example, in one aspect, a transmitting or receiving device of packet <NUM> may determine that the length of the applied SE <NUM> plus a length of the rounding error Δ is greater than the data symbol duration discussed above.

Accordingly, a transmitting device may transmit a "SE disambiguation indication" (or bit) as part of the packet <NUM> to indicate to a receiving device whether or not this issue is present. Accordingly, in some aspects, a transmitting device can set the SE disambiguation indication to a value of '<NUM>' when this issue is present, and the receiving device may, based at least in part on this indication, reduce a calculated number symbols within the packet <NUM> (e.g., calculated by the receiving device when receiving the transmission) by one.

<FIG> illustrates an exemplary transmission 700a of data packets 705a-b with SE in a multi-user scenario, in accordance with one embodiment. As described above, an AP <NUM> may transmit packets to more than one wireless communication device <NUM> at a time. In accordance with these aspects, the data within each of the packets transmitted to each wireless communication device <NUM> may vary. In some aspects, it may be desirable to add information (e.g., padding bits) to the packets including less data such that a length of the multiple packets is the same. As discussed above, in some aspects, it may be beneficial to add SE to the packets to afford the receiving device with additional processing time. In various aspects, if SE is needed at the end of one of the packets, SE is added to the end of all of the packets, so that all of the transmissions are of the same size. For example, as illustrated, the packet 705a received by a first station STA1 (e.g., wireless communication device <NUM>) may comprise SE 706a based upon the processing needs of a second station STA2. When the first station STA1 receives the packet 705a with SE 706a, the first station STA1 may ignore the SE 706a.

<FIG> illustrates an exemplary transmission 700b of data packets 710a-b with SE in a multi-user scenario, in accordance with one embodiment. In various aspects, a signaling extension (SE) 711a-b may be added to the end of a data transmission (e.g., after the last symbol of the last data packet). In some aspects, a receiving device may receive communications in accordance with a modulation and coding scheme (MCS). For example, the first station STA1 in <FIG> may receive communications in accordance with MCS2 while the second station STA2 may receive communications in accordance with MCS7. Accordingly, in various embodiments, multi-user transmissions may utilize SEs that are specialized for each different MCS of the receiving devices. In various embodiments, the SE may be added to the end of a data transmission to extend the amount of processing time a receiving device has to process the communication before another data transmission is sent. In one aspect, a SE may be any one of <NUM>, <NUM>, or <NUM>.

In some aspects, a receiving device may signal its MCS capabilities (e.g., thresholds) upon association. These thresholds may indicate, based on the MCS a receiving device is using, whether the receiving device is capable of receiving a communication without additional processing time, and otherwise, if additional processing time is required, how much. In one aspect, during association procedure, a wireless communication device <NUM> may use eight bits to signal two thresholds to an AP <NUM>. The first four of the bits can correspond to the first MCS threshold, and the latter four bits can correspond to the second MCS threshold. One embodiment of these thresholds is provided below in Table <NUM>. For example, wireless communication device <NUM> may signal "<NUM>" during association to signal that it requires <NUM> of processing time for MCS0 through MCS3, <NUM> of processing time for MCS4 through MCS7, and <NUM> of processing time for MCS8 and up.

<FIG> illustrates another exemplary transmission 700c of data packets 720a-b with SE in a multi-user scenario, in accordance with one embodiment. In some aspects, although the entire last data symbol may contain useful bits for the first station STA1, the first station STA1 may not need any additional processing time, based on the MCS the first station STA1 is utilizing to receive its portion of the transmission 700c. Further, in some aspects, the second station STA2 may have indicated that it requires <NUM> of additional processing time based on the MCS utilized, and the last data symbol for the second station STA2 may not contain any useful bits. Accordingly, rather than automatically adding a SE of <NUM> to the end of the transmission 700c based on the second station's STA2 thresholds indicated at association, the transmitting device may pad the final data symbol of the transmission for the second station STA2 so that the second station STA2 may still be afforded the <NUM> it needs. In some other aspects, a signaling extension of <NUM> may be added. Methods and apparatuses for providing this solution are described in further detail below.

<FIG> is a flow chart of an aspect of an exemplary process <NUM> of wireless communication. Process <NUM> may also be considered a method of wireless communication. Process <NUM> may be performed, in some aspects, by the device <NUM> discussed above with respect to <FIG>. For example, in some aspects, instructions stored in the memory <NUM> may configure the processor <NUM> to perform one or more of the functions discussed above with respect to process <NUM>.

In some aspects, process <NUM> may be utilized to transmit data with SE from an AP <NUM> to a wireless communication device <NUM>. Prior to the start of process <NUM>, the content of the data to be transmitted and the wireless communication devices <NUM> to which the data is to be transmitted may be known.

Block <NUM> of process <NUM> determines a corresponding a value (au) and a corresponding number of symbols required (Nsym,u) to transmit a corresponding plurality of data bits to each STA. This determination may be made, at least in part upon a first initial packet size of the transmission including the data bits for each STA. Further, the a value may be one of <NUM>, <NUM>, <NUM>, or <NUM>, and may correspond to one of the four boundaries described above. In some aspects, the a value for each STA may be based on a corresponding fraction of useful bits in a final symbol of the symbols required to transmit the corresponding plurality of data bits to the corresponding STA. In some aspects, the fraction of useful bits may be a fraction of bits encoding the corresponding plurality of data bits.

In block <NUM>, a maximum number of symbols (Nsym,init) and a maximum fraction of bits (a value (ainit)) for the plurality of data bits is determined based on the determined number of symbols and the a values for all STAs. In some aspects, the maximum fraction of bits may be a maximum fraction of useful bits. In some aspects, the maximum number of symbols may be determined separately from the maximum a value. In other aspects, the maximum a value is associated with an STA having the maximum number of symbols to be transmitted. This determination may be made according to the following formulas. <MAT><MAT> -> selects the kth user that has the maximum number of symbols to be transmitted.

ainit = ak -> select ainit as the a value corresponding to the user that has the maximum number of symbols to be transmitted.

In block <NUM>, pre-FEC padding is applied for the STAs until the data fills the total number of the maximum number of symbols (Nsym, init) up until a boundary identified by the maximum a value (ainit). As a result, the length of each of the data packets including the padding can be the same. The pre-FEC padding is applied by the media access control (MAC) layer and is considered to be part of the information bits to be decoded by the STA.

Block <NUM> determines whether any of the wireless communication devices (STAs) require an additional symbol, such as an additional short symbol. In some aspects, a STA may require an additional short symbol due to an encoding method of a data packet transmitted to the STA. For example, low density parity check (LDPC) encoded packets may require an additional short symbol in some aspects. In one aspect, a short symbol corresponds to one fourth of the length of the symbol. In accordance with this aspect, some aspects of block <NUM> may including altering one or more of the fraction of useful bits or the number of symbols required if any one of the plurality of wireless communication devices requires an additional short system. For example, the maximum a value and the maximum number of symbols required may be altered. If the maximum a value is less than <NUM>, then the value of <NUM> is added thereto in some aspects. However, if the maximum a value is <NUM>, then the value thereof is changed to <NUM>, and the value of <NUM> is added to the maximum number of symbols required. For example:
<MAT>
<MAT>.

Block <NUM> determines, for each of the plurality of wireless communication devices, a corresponding signaling extension length of extension bits (SE) for each STA (PEu) based at least in part on the corresponding fraction of useful bits (a value) and a modulation and coding scheme (MCS) capability of each of the plurality of wireless communication devices. For example, as described above, a wireless communications device <NUM> may have indicated that it requires <NUM> of processing time for MCS0 through MCS3, <NUM> of processing time for MCS4 through MCS7, and <NUM> of processing time for MCS8 and up. Accordingly, AP <NUM> may determine what MCS the device is currently using, and compare this to the thresholds set during association. For example, if the wireless communications device <NUM> is currently using MCS4, the AP <NUM> can determine that a <NUM> SE is necessary for this device. In some aspects, AP <NUM> may determine that some or all of this additional processing time is already available to the wireless communications device <NUM>, based at least in part on the a value. For example, if the a value is <NUM>, then the wireless communications device <NUM> may have <NUM> free after the end of the last symbol to process the received data. However, if the a value is <NUM>, for example, the wireless communications device <NUM> may only have <NUM> of time to process the data after the end of the symbol. Accordingly, in some aspects, AP <NUM> may determine that the wireless communications device <NUM> requires a SE of <NUM> to properly process the transmission. Similarly, if a wireless communications device <NUM> requires <NUM> of processing time, and the a value is <NUM>, the AP <NUM> may determine that the wireless communications device <NUM> requires a SE of <NUM> to be added to the end of the transmission. AP <NUM> may utilize the a value of the particular wireless communications device <NUM>, or may utilize the maximum a value for this purpose. AP <NUM> may perform this process for each of the wireless communications devices <NUM> receiving data in order to determine the maximum PE. Next, process <NUM> entails applying the maximum SE to the frame for all STAs. At this point, the transmission length for all of the STAs can be the same.

Block <NUM> may include generating a plurality of data packets, each data packet including the corresponding data bits and extension bits of the corresponding signaling extension length after the final symbol for each of the plurality of data bits. In some aspects, the plurality of data packets are generated to include the padding bits after the data bits discussed above. The padding bits may be included in the data packet until a bit location indicated by the maximum fraction of useful bits in the maximum number of symbols, based at least in part upon a length of the corresponding data bits.

Block <NUM> transmits the plurality of data packets to each of the plurality of wireless communication devices respectively. Each of the plurality of data packets may include one or more of the corresponding indication of the a value (e.g. or a corresponding first indication of the fraction of useful bits), SE disambiguation indication as described above with reference to <FIG>, and a second indication of whether an additional short symbol indication was added or is contained in the data packet based on the requirements of at least one of the wireless communications devices <NUM>.

In some aspects, one or more of the a values may be indicated by two bits, the SE disambiguation indication may be one bit, and the additional short symbol indication may be one bit (for a total of four bits). In one aspect, these bits may be provided in the header of the packet being transmitted, such as in an L-SIG or an HE-SIG of the packet header. It should be appreciated that additional functions may be present in process <NUM>, and that not all of the functions discussed above with respect to process <NUM> may be necessary. In some aspects, the transmitter <NUM> may be configured to perform the transmission described with respect to block <NUM>.

<FIG> is a flow chart of an aspect of an exemplary process <NUM> of wireless communication. In some aspects, process <NUM> may be utilized by a wireless communications device <NUM> to receive data with SE from an AP <NUM>. In some aspects, the process <NUM> may be performed by the device <NUM>, discussed above with respect to <FIG>. For example, in some aspects, instructions stored in the memory <NUM> may configure the processor <NUM> to perform one or more of the functions discussed below with respect to process <NUM>.

Block <NUM> determines a number of symbols and an applied SE based on packet length information and a SE disambiguation indication. As described above, this information may be indicated in a header of a packet that a device, performing process <NUM>, such as the device <NUM>, receives. The packet may be received, in some aspects, by the receiver <NUM>.

In block <NUM>, the a value is updated based on the additional short symbol indication. This updating may be the reverse of the process performed by the AP <NUM>. For example, if the a value is greater than <NUM>, then a value of <NUM> may be subtracted from the a value. However, if the a value is <NUM>, then the a value may be set to <NUM>, and the calculated number of symbols may be reduced by one. For example, if LDPC additional short symbol bit = <NUM>:
<MAT>
<MAT>.

In block <NUM>, a data symbol is decoded utilizing the applied PE. For example, the data symbol may be decoded from the received packet discussed above based on the PDPC decoding process, and the wireless communication device <NUM> may utilize the processing time provided by SE as a buffer to complete processing of the data transmission. Block <NUM> may include processing the decoded data symbol. For example, the decoded data symbol may be utilized to form byte values of the received packet.

<FIG> is a flow chart of an aspect of an exemplary process <NUM> of wireless communication. In some aspects, process <NUM> may be utilized to transmit data with SE from an AP <NUM> to a wireless communication device <NUM>. Process <NUM> may be similar to process <NUM> of <FIG>, but may provide additional or alternative processing efficiencies. Prior to the start of process <NUM>, the content of the data to be transmitted and the wireless communication devices <NUM> to which the data is to be transmitted may be known. As illustrated, process <NUM> first involves determining the a value and the number of symbols required for each STA based on the packet size for each STA. This determination may be made, at least in part upon the packet size of the transmission for each STA. Further, the a value may be one of <NUM>, <NUM>, <NUM>, or <NUM>, and may correspond to one of the four boundaries described above.

Next, process <NUM> entails determining the maximum number of symbols and an a value from among the determined number of symbols and a values for all STAs. In some aspects, the maximum number of symbols may be determined separately from the maximum a value. In other aspects, the maximum a value corresponds to the a value associated with the STA that has the maximum number of symbols to be transmitted. Next, process <NUM> entails determining SE for each STA based on the device capability (e.g., <NUM>, <NUM>, or <NUM> based on the current MCS as compare to the thresholds indicated by the wireless communications device <NUM> at association).

Next, process <NUM> entails determining whether any STA has a SE that is greater than all other STAs, a number of symbols that is less than the maximum, and an a value that is less than <NUM>. This STA is referred to below as an "identified" STA. For example, AP <NUM> may utilize the following formulas:
<MAT>
<MAT>
<MAT>.

Next, process <NUM> entails reducing the number of symbols for the identified STA by one and setting the STA's a value to <NUM>, unless an additional short symbol is required, then set the STA's a value to <NUM>. This process will be performed for each of the identified STAs. For example:
<MAT>.

If LDPC extra short symbol is required for that STA (or any other STA): au = <NUM>.

Next, process <NUM> entails applying pre-FEC padding for all STAs until the data fills the total number of the maximum number of symbols (Nsym, init), up until the boundary identified by the maximum a value (ainit). At this point, the length of each of the data packets including the padding can be the same. However, for identified STAs, a different padding may be used. In some aspects, pre-FEC padding is applied until the boundary indicated by the STA's own a value (au), and post-FEC padding is applied for the last symbol.

Next, process <NUM> entails determining whether any STA requires an additional short symbol. In some aspects, a device may require an additional short symbol due to LDPC encoding. In one aspect, a short symbol corresponds to one fourth of the length of the symbol. In accordance with this aspect, the maximum a value and the maximum number of symbols required may be altered. For example, if the maximum a value is less than <NUM>, then the value of <NUM> is added thereto. However, if the maximum a value is <NUM>, then the value thereof is changed to <NUM>, and the value of <NUM> is added to the maximum number of symbols required. For example:
<MAT>
<MAT>.

If the maximum number of symbols increases by <NUM> (as shown in the above example), then the LDPC encoding process is repeated taking the extra symbol and the new a value into account. Pre-FEC padding is applied to each STA in accordance with the new a value. For some STAs (identified earlier as satisfying the conditions) the number of symbols is increased but the a value does not change.

Next, process <NUM> entails determining SE for each STA based on each STA's capability and the a value, similar to process <NUM> described above with reference to <FIG>. AP <NUM> may utilize the a value of the particular wireless communications device <NUM>, or may utilize the maximum a value for this purpose. AP <NUM> may perform this process for each of the wireless communications devices <NUM> receiving data in order to determine the maximum PE. However, for the identified STAs, a different determination may be made. In one aspect, the entire last symbol may be used as the SE for the device, and therefore no additional SE may be required. Therefore, AP <NUM> may rule the identified STAs out in making the determination of the maximum SE to apply. Next, process <NUM> entails applying the maximum SE to the frame for all STAs. At this point, the transmission length for all of the STAs can be the same.

Next, process <NUM> entails transmitting the a value, a SE disambiguation indication as described above with reference to <FIG>, and additional short symbol indication that may indicate whether an additional short symbol was added based on the requirements of at least one of the wireless communications devices <NUM>. In some aspects, the a value may be indicated by two bits, the SE disambiguation indication may be one bit, and the additional short symbol indication may be one bit (for a total of four bits). In one aspect, these bits may be provided in the header of the packet being transmitter, such as in an L-SIG or an HE-SIG of the packet header. It should be appreciated that additional steps may be present in process <NUM>, and that not all of the steps of process <NUM> may be necessary.

<FIG> is a flow chart of an aspect of an exemplary process <NUM> of wireless communication. In some aspects, process <NUM> discussed below with respect to <FIG> may be performed by the device <NUM>. For example, instructions in the memory <NUM> may configure the processor <NUM> to perform one or more of the functions discussed below with respect to process <NUM>.

In some aspects, process <NUM> may be utilized by a wireless communications device <NUM> to receive data with SE from an AP <NUM>.

Block <NUM> determines a number of symbols and an applied SE based on packet length information and a SE disambiguation indication. As described above, this information may be indicated in the header of a packet received by a device performing process <NUM>. For example, this information may be in a packet that the wireless communications device <NUM> is receiving.

Block <NUM> determines whether to adjust the determined a value and the number of symbols based on a device capability. For example, in one aspect, a receiving device may determine whether the applied SE is less than an amount of SE required for the receiving device based on the a value provided and a device capability indicated at association. Alternatively, an indication may be provided to each of the wireless communication devices <NUM> that satisfy this criteria, and each of the receiving devices would check this indication to determine whether it is one of the identified devices.

Block <NUM> updates the a value based on the device capability and the additional short symbol indication. This updating may be the reverse of the process performed by the AP <NUM>. For example, for devices not identified in the prior step, if the a value is greater than <NUM>, then a value of <NUM> may be subtracted from the a value. However, if the a value is <NUM>, then the a value may be set to <NUM>, and the calculated number of symbols may be reduced by one. For example, if LDPC additional short symbol bit = <NUM>: <MAT>is unchanged <MAT>.

However, for devices identified by the prior step, the devices may decrease or decrement the number of symbols by a value of <NUM>, and if the additional short symbol indication is set to the value of <NUM>, then set a equal to the value of <NUM>, but if the additional short symbol indication is set to the value of <NUM>, then set a equal to the value of <NUM>.

Block <NUM> decodes the data symbol utilizing the applied PE. For example, the data symbol may be decoded based on the PDPC decoding process, and the wireless communication device <NUM> may utilize the processing time provided by SE as a buffer to complete processing of the data transmission.

For certain bandwidths (BW), MCS, and number of spatial streams (NSS), certain MCS may be "excluded. " This MCS exclusion may be based, at least in part, on when a combination of the above yields values for NCBPS,short (number of coded bits per short symbol), NDBPS,short (number of data bits in a short symbol) or NDBPS,Short/NES (number of binary convolutional codes (BCC) encoders required) that are not integers. In one aspect, the following formulas may be used:
<MAT>
<MAT>.

Accordingly, in order to avoid MCS exclusion, all three of the parameters are required to be integers. In some aspects, the value of NSD,short should be such that it is one fourth of that of NSD,long. In one aspect, the values identified in Table <NUM> below may be used.

For example, in the <NUM> BW, each boundary indicated by the a values <NUM>-<NUM> will be <NUM> tones apart. In other words, when data in the last symbol of a transmission is only within the first <NUM> tones, then a = <NUM>, when data in the last symbol of a transmission is outside of the first <NUM> tones but within the first <NUM> tones, then a = <NUM>, when data in the last symbol of a transmission is outside the first <NUM> tones but within the first <NUM> tones, then a = <NUM>, and when data in the last symbol of a transmission is outside of the first <NUM> tones but within the available <NUM> tones, then a = <NUM>. When the value of NSD,short is not exactly one fourth of NSD in Table <NUM>, the first three boundaries indicated by the a values of <NUM>, <NUM>, and <NUM>, will be NSD tones apart, and the remaining a value of <NUM> will correspond to the remaining balance of tones. For example, in the <NUM> BW, when data in the last symbol of a transmission is only within the first <NUM> tones, then a = <NUM>, when data in the last symbol of a transmission is outside of the first <NUM> tones but within the first <NUM> tones, then a = <NUM>, when data in the last symbol of a transmission is outside the first <NUM> tones but within the first <NUM> tones, then a = <NUM>, and when data in the last symbol of a transmission is outside of the first <NUM> tones but within the available <NUM> tones, then a = <NUM>. Although NSD is listed as <NUM> for the BW of <NUM>, <NUM> tones may be alternatively used. However, this alternative choice may not satisfy 1024QAM with a code rate of <NUM>/<NUM>.

<FIG> is a flowchart of a method of receiving a data packet of the format disclosed here. In some aspects, process <NUM> may be performed by the wireless device <NUM>. For example, in some aspects, the receiver <NUM> may be configured to receive the packet and the processor <NUM> may be configured to decode the packet as described above. In some aspects, the reception of the packet may be controlled by the processor <NUM>. For example, the processor <NUM> may indicate to the receiver that it should configure itself to receive a packet, and then may copy data from the receiver <NUM> to the memory <NUM> after the packet has been received.

In block <NUM>, a data packet is received. The data packet includes an indication of a fraction of useful data bits, and the data bits. In some aspects, the data packet may include an indication of whether an additional short symbol is contained in the data packet, and/or a signaling extension after a final symbol of the data packet.

In block <NUM>, the data packet is processed based at least in part on the fraction of useful bits. In some aspects, processing the data packet may include decoding the data packet based on one or more of the indications in the data packet. In some aspects, the data packet may be processed based on the indication of whether the additional short symbol is contained in the data packet. For example, in some aspects, the data bits may be extracted from the packet based on the useful data bits indication. For example, the indicated useful bits may be copied to a buffer and processed based on a predetermined packet format. For example, in some aspects, a frame check sequence may be extracted from the end of the packet based on the number of useful bits indication. The frame check sequence may then be used to verify an integrity of the packet.

In some embodiments an apparatus for wireless communication may perform any of the processes <NUM>-<NUM> described in <FIG>. In an exemplary embodiment, the apparatus for wireless communication is similar to the wireless communication device <NUM> of <FIG>. In some embodiments, the apparatus comprises means for generating a first message requesting channel state information from one or more wireless communication devices. The generated first message may comprise a header and a payload. The header of the first message may comprise a plurality of fields of a first field type which are useable to determine the requested channel state information, and the payload of the first message may comprise channel state information parameters. The apparatus may further comprise means for transmitting the first message to the one or more wireless communication devices.

A person/one having ordinary skill in the art would understand that information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that can be referenced throughout the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The disclosure is not intended to be limited to the implementations shown herein, but is to be accorded the widest scope consistent with the claims. The word "exemplary" is used exclusively herein to mean "serving as an example, instance, or illustration.

As an example, "at least one of: A, B or C" is intended to cover A or B or C or A and B or A and C or B and C or A, B and C or 2A or 2B or 2C and so on.

Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable sub-combination. Moreover, although features can be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination can be directed to a sub-combination or variation of a sub-combination.

The various operations of methods described above may be performed by any suitable means capable of performing the operations, such as various hardware and/or software component(s), circuits, and/or module(s). Generally, any operations illustrated in the Figures may be performed by corresponding functional means capable of performing the operations.

As used herein, the term interface may refer to hardware or software configured to connect two or more devices together. For example, an interface may be a part of a processor or a bus and may be configured to allow communication of information or data between the devices. The interface may be integrated into a chip or other device. For example, in some aspects, an interface may comprise a receiver configured to receive information or communications from a device at another device. The interface (e.g., of a processor or a bus) may receive information or data processed by a front end or another device or may process information received. In some aspects, an interface may comprise a transmitter configured to transmit or communicate information or data to another device. Thus, the interface may transmit information or data or may prepare information or data for outputting for transmission (e.g., via a bus).

The various illustrative logical blocks, modules and circuits described in connection with the present disclosure may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components or any combination thereof designed to perform the functions described herein. 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.

In one or more aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. A storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, 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. Disk and disc, as used herein, 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. Thus, in some aspects computer readable medium may comprise non-transitory computer readable medium (e.g., tangible media). In addition, in some aspects computer readable medium may comprise transitory computer readable medium (e.g., a signal).

Claim 1:
A method of extending a first message (<NUM>) in a wireless communication network operating according to an IEEE <NUM> protocol, comprising:
determining a modulation and coding scheme capability of a destination device of the first message (<NUM>);
determining a number of bits in a final symbol of the first message (<NUM>);
determining a length of a signaling extension, SE, (<NUM>) based on the modulation and coding scheme capability and the number of bits, wherein the SE (<NUM>) follows the final symbol in the first message (<NUM>); and
transmitting the first message (<NUM>) with a transmission length, TXTIME, of the first message (<NUM>) in a legacy preamble/HE preamble (<NUM>) of the first message (<NUM>), with the SE (<NUM>) of the determined length, and with an SE disambiguation indication to the destination device, wherein the SE disambiguation indication indicates whether the length of the SE (<NUM>) plus a length of a rounding error, Δ, is greater than a data symbol duration, Tsym, wherein the rounding error, Δ, is a difference between the end of the SE (<NUM>) and the end of the first message (<NUM>) according to the quantized transmission length, TXTIME.