Patent Publication Number: US-10785777-B2

Title: Apparatus and method for receiving data frames

Description:
CROSS-REFERENCE TO A RELATED APPLICATION 
     The present Application for Patent is a continuation application of Non-Provisional application Ser. No. 15/009,733 filed in the U.S. Patent and Trademark Office on Jan. 28, 2016, the entire content of which is incorporated herein by reference as if fully set forth below in its entirety and for all applicable purposes. Non-Provisional application Ser. No. 15/009,733 claims priority to and the benefit of provisional patent application No. 62/147,479 filed in the U.S. patent office on Apr. 14, 2015, the entire content of which is incorporated herein by reference. 
    
    
     FIELD 
     Certain aspects of the present disclosure generally relate to wireless communications and, more particularly, to transmitting and receiving enhanced frames for transmission of orthogonal frequency division multiplexing (OFDM) signals, single carrier wideband (SC WB) signals, aggregated single carrier (SC) signals, OFDM MIMO (spatial) signals, SC WB MIMO (spatial) signals, and aggregated SC MIMO (spatial) signals. 
     BACKGROUND 
     This document is a Concept Design of suggested Frame Format for a currently-developed new protocol, which is being referred to as NG60 (Next Generation 60 GHz), or also known as Institute of Electrical and Electronics Engineers (IEEE) 802.11ay. It is a development on top of the existing standard IEEE 802.11ad (in the past also known as “WiGig”). 
     The main goal of the new standard or protocol is to increase the throughput, and extend coverage as well as lower power consumption (e.g., average energy per bit). It is also clear that the new standard shall be backward compatible and should allow 802.11ad (legacy) devices to coexist in the same environment. 
     SUMMARY 
     Certain aspects of the present disclosure provide an apparatus for wireless communications. The apparatus comprises a processing system configured to generate a frame comprising a preamble, a first header, and a second header, wherein the preamble and the first header are configured to be decoded by a first device operating according to a first protocol, the second header not being configured to be decoded by the first device, and wherein the preamble, the first header, and the second header are configured to be decoded by a second device operating according to a second protocol; and an interface configured to output the frame for transmission by way of the at least one antenna. 
     Certain aspects of the present disclosure provide a method for wireless communications. The method comprises generating a frame comprising a preamble, a first header, and a second header, wherein the preamble and the first header are configured to be decoded by a first device operating according to a first protocol, the second header not being configured to be decoded by the first device, and wherein the preamble, the first header, and the second header are configured to be decoded by a second device operating according to a second protocol; and outputting the frame for transmission. 
     Certain aspects of the present disclosure provide an apparatus for wireless communications. The apparatus comprises means for generating a frame comprising a preamble, a first header, and a second header, wherein the preamble and the first header are configured to be decoded by a first device operating according to a first protocol, the second header not being configured to be decoded by the first device, and wherein the preamble, the first header, and the second header are configured to be decoded by a second device operating according to a second protocol; and means for outputting the frame for transmission. 
     Certain aspects of the present disclosure provide a computer readable medium having instructions stored thereon for generating a frame comprising a preamble, a first header, and a second header, wherein the preamble and the first header are configured to be decoded by a first device operating according to a first protocol, the second header not being configured to be decoded by the first device, and wherein the preamble, the first header, and the second header are configured to be decoded by a second device operating according to a second protocol; and outputting the frame for transmission. 
     Certain aspects of the present disclosure provide a wireless node. The wireless node comprises at least one antenna, a processing system configured to generate a frame comprising a preamble, a first header, and a second header, wherein the preamble and the first header are configured to be decoded by a first device operating according to a first protocol, the second header not being configured to be decoded by the first device, and wherein the preamble, the first header, and the second header are configured to be decoded by a second device operating according to a second protocol; and an interface configured to output the frame for transmission by way of the at least one antenna. 
     Aspects of the present disclosure also provide various methods, means, and computer program products corresponding to the apparatuses and operations described above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of an exemplary wireless communications network in accordance with certain aspects of the present disclosure. 
         FIG. 2A  is a block diagram of an exemplary access point or user device in accordance with certain aspects of the present disclosure. 
         FIG. 2B  illustrates a block diagram of an access point (generally, a first wireless node) and a user device (generally, a second wireless node) in accordance with certain aspects of the present disclosure. 
         FIG. 3A  illustrates an exemplary frame or frame portion in accordance with certain aspects of the present disclosure. 
         FIG. 3B  illustrates an exemplary Extended Directional Multigigabit (EDMG) Header in accordance with certain aspects of the present disclosure. 
         FIGS. 4A-4B  illustrate exemplary frames for transmission via an orthogonal frequency division multiplexing (OFDM) signal in accordance with certain aspects of the present disclosure. 
         FIGS. 5A-5D  illustrate exemplary frames for transmission via a single carrier wideband (SC WB) signal in accordance with certain aspects of the present disclosure. 
         FIG. 5E  illustrates an exemplary transmit power profile for an exemplary frame for transmission via a single carrier wideband (SC WB) signal in accordance with certain aspects of the present disclosure. 
         FIGS. 6A-6D  illustrate exemplary frames for transmission via an aggregated single carrier (SC) signal in accordance with certain aspects of the present disclosure. 
         FIG. 7  illustrates an exemplary frame for transmission via a plurality (e.g., three (3)) of spatial multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) signal in accordance with certain aspects of the present disclosure. 
         FIGS. 8A-8C  illustrate exemplary frames for transmission via a plurality (e.g., two (2), four (4), and eight (8)) of spatial multiple input multiple output (MIMO) single carrier wideband (SC WB) signal in accordance with certain aspects of the present disclosure. 
         FIGS. 9A-9B  illustrate exemplary frames for transmission via a plurality (e.g., two (2) and three (3)) of spatial multiple input multiple output (MIMO) aggregated single carrier (SC) signal in accordance with certain aspects of the present disclosure. 
         FIG. 10  illustrates a block diagram of an exemplary wireless device in accordance with certain aspects of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Aspects of the present disclosure provide techniques for performing channel estimation of a bonded channel formed by bonding a plurality of channels by using channel estimation training sequences transmitted in each of the plurality of channels. 
     Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This 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. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. 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 disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure 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 disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim. 
     The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. 
     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. 
     An Example Wireless Communication System 
     The techniques described herein may be used for various broadband wireless communication systems, including communication systems that are based on an orthogonal multiplexing scheme. Examples of such communication systems include Spatial Division Multiple Access (SDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single-Carrier Frequency Division Multiple Access (SC-FDMA) systems, and so forth. An SDMA system may utilize sufficiently different directions to simultaneously transmit data belonging to multiple user terminals. A TDMA system may allow multiple user terminals to share the same frequency channel by dividing the transmission signal into different time slots, each time slot being assigned to different user terminal. An OFDMA system utilizes orthogonal frequency division multiplexing (OFDM), which is a modulation technique that partitions the overall system bandwidth into multiple orthogonal sub-carriers. These sub-carriers may also be called tones, bins, etc. With OFDM, each sub-carrier may be independently modulated with data. An SC-FDMA system may utilize interleaved FDMA (IFDMA) to transmit on sub-carriers that are distributed across the system bandwidth, localized FDMA (LFDMA) to transmit on a block of adjacent sub-carriers, or enhanced FDMA (EFDMA) to transmit on multiple blocks of adjacent sub-carriers. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDMA. 
     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 Node B, a Radio Network Controller (“RNC”), an evolved Node B (eNB), a Base Station Controller (“BSC”), a Base Transceiver Station (“BTS”), a Base Station (“BS”), a Transceiver Function (“TF”), a Radio Router, a Radio Transceiver, a Basic Service Set (“BSS”), an Extended Service Set (“ESS”), a Radio Base Station (“RBS”), or some other terminology. 
     An access terminal (“AT”) may comprise, be implemented as, or known as a subscriber station, a subscriber unit, a mobile station, a remote station, a remote terminal, a user terminal, a user agent, a user device, user equipment, a user station, 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, a Station (“STA”), 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 smart phone), a computer (e.g., a laptop), a portable communication device, 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 global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium. In some aspects, the node is a wireless node. Such wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as the Internet or a cellular network) via a wired or wireless communication link. 
     With reference to the following description, it shall be understood that not only communications between access points and user devices are allowed, but also direct (e.g., peer-to-peer) communications between respective user devices are allowed. Furthermore, a device (e.g., an access point or user device) may change its behavior between a user device and an access point according to various conditions. Also, one physical device may play multiple roles: user device and access point, multiple user devices, multiple access points, for example, on different channels, different time slots, or both. 
       FIG. 1  illustrates a block diagram of an exemplary wireless communications network  100  in accordance with certain aspects of the present disclosure. The communications network  100  comprises an access point  102 , a backbone network  104 , a legacy user device  106 , an updated legacy user device  108 , and a new protocol user device  110 . 
     The access point  102 , which may be configured for a wireless local area network (LAN) application, may facilitate data communications between the user devices  106 ,  108 , and  110 . The access point  102  may further facilitate communications data communications between devices coupled to the backbone network  104  and any one or more of the user devices  106 ,  108 , and  110 . 
     In this example, the access point  102  and the legacy user device  106  data communicate between each other using a legacy protocol. One example of a legacy protocol includes Institute of Electrical and Electronics Engineers (IEEE) 802.11ad. According to this protocol, data communications between the access point  102  and the legacy user device  106  are effectuated via transmission of data frames that comply with the 802.11ad protocol. As discussed further herein, an 802.11ad data frame includes a preamble consisting of a short training field (STF) sequence and a channel estimation (CE) sequence, a header, a payload data, and an optional beamforming training field. 
     The STF sequence includes a plurality of concatenated Golay sequences (Ga 128 ) followed by a negative Golay sequence (−Ga 128 ) to signify the end of the STF sequence. The STF sequence may assist a receiver in setting up its automatic gain control (AGC), timing, and frequency setup for accurately receiving the rest of the frame and subsequent frames. 
     In the case of a single carrier (SC) transmission mode, the CEF includes a Gu 512  sequence (consisting of the following concatenated Golay sequences (−Gb 128 , −Ga 128 , Gb 128 , −Ga 128 ) followed by a Gv 512  sequence (consisting of the following concatenated Golay sequences (−Gb 128 , Ga 128 , −Gb 128 , −Ga 128 ), and ending with a Gv 128  (same as −Gb 128 ) sequence. In the case of an orthogonal frequency division multiplexing (OFDM) transmission mode, the CEF includes a Gv 512  sequence followed by a Gu 512  sequence, and ending with a Gv 128  sequence. The CEF assists the receiver in estimating the transfer function or frequency response to a channel through which the 802.11ad data frame is transmitted. 
     The header 802.11ad data frame includes information about the frame. Such information includes a scrambler initiation field, which specifies a seed for the scrambling applied to the remainder of the header and the payload data for data whitening purposes. The header also includes the modulation and coding scheme (MCS) field to indicate one out of 12 defined MCS used for transmitting the payload data portion of the transmitted signal. The header includes a length field to indicate the length of the payload data in octets. The header further includes a training length field to indicate a length of the optional beam forming training sequence at the end of the frame. Additionally, the header includes a packet type field to indicate whether the optional beam forming field pertains to transmission or reception. Further, the header includes a header checksum (HCS) field to indicate a cyclic redundancy code (CRC) (e.g., CRC-32) checksum over the header bits. 
     Referring again to  FIG. 1 , the legacy user device  106  is capable of decoding the entire 802.11ad data frame. The new frame disclosed herein, which may be subsequently adopted for a new standard or protocol, such as the currently-in-development IEEE 802.11ay, provides some backward compatibility feature. As discussed in more detail herein, the new frame includes the preamble (the STF and the CEF) and the header of the 802.11ad, but one or more additional portions pertaining to the proposed new protocol. Accordingly, the legacy user device  106  is configured to decode the 802.11ad preamble and header portion of the new frame, but is not configured to decode the remaining portion of the new frame. The legacy user device  106  may decode the data in the length field of the legacy header portion of the new frame in order to calculate a network allocation vector (NAV) to determine the length of the new frame for transmission collision avoidance purposes. 
     The updated legacy user device  108  also operates under the legacy 802.11ad protocol, and is able to communicate with the access point  102  using 802.11ad data frames. However, the frame processing capability of the updated legacy user device  108  has been updated to interpret certain bits in the legacy header of the new frame that indicate an attribute of the new frame, as discussed further herein. In accordance with the legacy 802.11ad protocol, these bits are allocated to one or more least significant bits (LSB) of the data length in the legacy header. That is, in accordance with the new frame, the allocated LSB of the data length field of the legacy header portion are used to indicate a transmission power difference between a first portion of the new frame and a second portion of the new frame in accordance with a certain transmission mode associated with the new frame. These bits allow the updated legacy user device to anticipate the power difference (an increase) for signal interference management purposes. Although in this example, the allocation of the LSB length bits signify the aforementioned power difference, it shall be understood that these bits may be allocated for other purposes. 
     The new protocol user device  110  is capable of communicating with the access point  102  using the new data frame, which some or all features of the new frame may be adopted for the currently-under-development 802.11ay protocol. As discussed further herein, the new data frame includes the legacy 802.11ad preamble and header, with the legacy header slightly modified to indicate the transmission mode associated with the new frame and, as previously discussed, a transmission power difference between a first portion of the new frame and a second portion of the new frame. The slight modification to the legacy header portion of the new frame may not impact the decoding of the legacy header by the legacy user device  106  and the updated legacy user device  108 . For instance, the bits in the legacy header portion of the new frame to indicate the transmission mode are reserved bits in the standard 802.11ad legacy header. 
     In addition to the legacy preamble and header portion, the new frame further comprises an extended header. As discussed in more detail herein, the extended header comprises a plurality of fields for indicating various attributes for the new frame. Such attributes includes payload data length, number of low density parity check (LDPC) data blocks appended to the extended header, the number of spatial streams, the number of bonded channels, the leftmost (lowest frequency) channel of the bonded channels, the MCS for the payload data of the new frame, the transmit power difference between different portion of the frame, and other information. As mentioned above, the extended header may further be appended with payload data that is not in the payload portion of the new frame. For short messages, all of the payload data may appended to the extended header, thereby avoiding the need for transmitting the “separate” payload data portion of the new frame, which adds significant overhead to the frame. 
     The new data frame is configured to provide additional features to improve data throughput by employing higher data modulation schemes, channel bonding, channel aggregation, and improved spatial transmission via multiple input multiple output (MIMO) antenna configurations. For instance, the legacy 802.11ad protocol includes BPSK, QPSK, and 16QAM available modulation schemes. According to the new protocol, higher modulation schemes, such as 64QAM, 64APSK, 128APSK, 256QAM, and 256APSK are available. Additionally, a plurality of channels may be bonded or aggregated to increase data throughput. Further, such bonded or aggregated channels may be transmitted by way of a plurality of spatial transmissions using a MIMO antenna configuration. 
       FIG. 2A  illustrates a block diagram of an exemplary apparatus  200  for wireless communications in accordance with certain aspects of the present disclosure. The apparatus  200  may be an exemplary implementation of the access point  102 , legacy user device  106 , updated legacy user device  108 , and new protocol user device  110 , previously discussed. The apparatus  200  comprises a transmit (Tx) frame processing system  202 , a receive (Rx) frame processing system  206 , and an interface  208  coupled to one or more antennas. 
     The Tx frame processing system  202  receives data for transmission to a remote device, and parameters for specifying the Tx frame supporting the data. Based on the Tx frame parameters, the Tx frame processing system  202  generates a transmit frame including the data intended for the remote device. The interface  208  is configured to output the transmit frame for transmission to a remote device by way of one or more antennas. In the case of multiple antennas, the interface  208  may output the transmit frame for transmission via spatial transmissions with the antennas being in a MIMO configuration. 
     The interface  208  is also configured to receive a signal including a data frame transmitted by a remote device. The interface  208  receives the signal by way of the one or more antennas. In the case of multiple antennas, the signal may be received in a spatial or directional manner with the antennas being in a MIMO configuration. The interface  208  outputs the data frame to the Rx frame processing system  206 . The Rx frame processing system  206  receives frame parameters associated with the received data frame, and processes the frame to produce the data included in the frame. 
     In the case where the apparatus  200  is an exemplary implementation of the of the access point  102 , which, in this example, is capable of communicating with user devices using the 802.11ad legacy protocol and the new 802.11ay protocol, the Tx frame processing system  202  and Rx frame processing system  206  are configured to process both 802.11ad legacy and the new 802.11ay protocol transmit and receive frames. 
     Similarly, in the case where the apparatus  200  is an exemplary implementation of the new protocol user device  110 , which, in this example, is capable of communicating with the access point  102  using the 802.11ad legacy protocol and the new 802.11ay protocol, the Tx frame processing system  202  and Rx frame processing system  206  are configured to process both 802.11ad legacy and the new 802.11ay protocol transmit and receive frames. It shall be understood that the new protocol user device  110  need not be configured for processing the legacy 802.11ad frames, but may be done so that the user device  110  is capable of communicating with 802.11ad access points or other 11ad devices. 
     In the case where the apparatus  200  is an exemplary implementation of the of the legacy 802.11ad user device  106 , which, in this example, is capable of only communicating with the access point  102  using the 802.11ad legacy protocol, the Tx frame processing system  202  and Rx frame processing system  206  are configured to process 802.11ad legacy transmit and receive frames for transmitting and receiving data, and not the new 802.11ay protocol frame. However, the legacy 802.11ad user device  106  may be configured to receive and decode the legacy header portions of the new protocol frame to, for example, calculate a network allocation vector (NAV) to determine a duration of the new protocol frame for the purpose of avoiding transmission collision and determining when the communication medium is available for transmission of a legacy 802.11ad frame. 
     The description in previous paragraph applies to the updated legacy user device  108 . However, as previously discussed, the updated legacy user device  108  may be configured to decode certain bits in the legacy header portion of the new protocol frame. Such bits may be reserved bits and reallocated bits in the legacy 802.11ad frame. These bits indicate the transmission mode of the new frame and the transmit power difference between a first portion of the new frame (e.g., the legacy preamble and header, and an extended header per the new frame protocol) and a second portion of the new frame (e.g., a new protocol preamble, payload data, and optional beam training sequence (TRN)) in a single carrier wideband (SC WB) transmission mode in accordance with the new protocol, as discussed in more detail herein. The update legacy user device  108  uses the information in those bits to anticipate a power increase for interference management purposes. 
       FIG. 2B  illustrates a block diagram of a wireless communication network  210  including an access point  212  (generally, a first wireless node) and a user device  250  (generally, a second wireless node). The access point  212  is a transmitting entity for the downlink and a receiving entity for the uplink. The user device  250  is a transmitting entity 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. 
     It shall be understood that the access point  212  may alternatively be a user device, and the user device  250  may alternatively be an access point. 
     For transmitting data, the access point  212  comprises a transmit data processor  220 , a frame builder  222 , a transmit processor  224 , a plurality of transceivers  226 - 1  to  226 -N, and a plurality of antennas  230 - 1  to  230 -N. The access point  212  also comprises a controller  234  for controlling operations of the access point  212 . 
     In operation, the transmit data processor  220  receives data (e.g., data bits) from a data source  215 , and processes the data for transmission. For example, the transmit data processor  220  may encode the data (e.g., data bits) into encoded data, and modulate the encoded data into data symbols. The transmit data processor  220  may support different modulation and coding schemes (MCSs). For example, the transmit data processor  220  may encode the data (e.g., using low-density parity check (LDPC) encoding) at any one of a plurality of different coding rates. Also, the transmit data processor  220  may modulate the encoded data using any one of a plurality of different modulation schemes, including, but not limited to, BPSK, QPSK, 16QAM, 64QAM, 64APSK, 128APSK, 256QAM, and 256APSK. 
     In certain aspects, the controller  234  may send a command to the transmit data processor  220  specifying which modulation and coding scheme (MCS) to use (e.g., based on channel conditions of the downlink), and the transmit data processor  220  may encode and modulate data from the data source  215  according to the specified MCS. It is to be appreciated that the transmit data processor  220  may perform additional processing on the data such as data scrambling, and/or other processing. The transmit data processor  220  outputs the data symbols to the frame builder  222 . 
     The frame builder  222  constructs a frame (also referred to as a packet), and inserts the data symbols into a payload data of the frame. The frame may include a legacy (first) preamble (e.g., STF and CEF), a legacy header, an extended header, a new protocol (second) preamble (e.g., second STF and CEF), a payload data, and an optional beam training sequence (TRN). The preamble may include a short training field (STF) sequence and a channel estimation field (CEF) to assist the user device  250  in receiving the frame. The legacy and extended header may include information related to the data in the payload such as the length of the data and the MCS used to encode and modulate the data. This information allows the user device  250  to demodulate and decode the data. The data in the payload may be divided among a plurality of blocks, wherein each block may include a portion of the data and a guard interval (GI) to assist the receiver with phase tracking. The frame builder  222  outputs the frame to the transmit processor  224 . 
     The transmit processor  224  processes the frame for transmission on the downlink. For example, the transmit processor  224  may support different transmission modes such as an orthogonal frequency-division multiplexing (OFDM) transmission mode and a single-carrier (SC) transmission mode. In this example, the controller  234  may send a command to the transmit processor  224  specifying which transmission mode to use, and the transmit processor  224  may process the frame for transmission according to the specified transmission mode. The transmit processor  224  may apply a spectrum mask to the frame so that the frequency constituent of the downlink signal meets certain spectral requirements. 
     In certain aspects, the transmit processor  224  may support multiple-output-multiple-input (MIMO) transmission. In these aspects, the access point  212  may include multiple antennas  230 - 1  to  230 -N and multiple transceivers  226 - 1  to  226 -N (e.g., one for each antenna). The transmit processor  224  may perform spatial processing on the incoming frames and provide a plurality of transmit frame streams for the plurality of antennas. The transceivers  226 - 1  to  226 -N receive and processes (e.g., converts to analog, amplifies, filters, and frequency upconverts) the respective transmit frame streams to generate distinct spatially-diverse transmit signals for transmission via the antennas  230 - 1  to  230 -N, respectively. 
     For transmitting data, the user device  250  comprises a transmit data processor  260 , a frame builder  262 , a transmit processor  264 , a plurality of transceivers  266 - 1  to  266 -M, and a plurality of antennas  270 - 1  to  270 -M (e.g., one antenna per transceiver). The user device  250  may transmit data to the access point  212  on the uplink, and/or transmit data to another user device (e.g., for peer-to-peer communication). The user device  250  also comprises a controller  274  for controlling operations of the user device  250 . 
     In operation, the transmit data processor  260  receives data (e.g., data bits) from a data source  255 , and processes (e.g., encodes and modulates) the data for transmission. The transmit data processor  260  may support different MCSs. For example, the transmit data processor  260  may encode the data (e.g., using LDPC encoding) at any one of a plurality of different coding rates, and modulate the encoded data using any one of a plurality of different modulation schemes, including, but not limited to, BPSK, QPSK, 16QAM, 64QAM, 64APSK, 128APSK, 256QAM, and 256APSK. In certain aspects, the controller  274  may send a command to the transmit data processor  260  specifying which MCS to use (e.g., based on channel conditions of the uplink), and the transmit data processor  260  may encode and modulate data from the data source  255  according to the specified MCS. It is to be appreciated that the transmit data processor  260  may perform additional processing on the data. The transmit data processor  260  outputs the data symbols to the frame builder  262 . 
     The frame builder  262  constructs a frame, and inserts the received data symbols into a payload data of the frame. The frame may include a legacy preamble, a legacy header, an extended header, a new protocol preamble, a payload data, and an optional beam training sequence (TRN). The legacy and the new protocol preamble may each include an STF and a CEF to assist the access point  212  and/or other user device in receiving the frame. The legacy and extended header may include information related to the data in the payload such as the length of the data and the MCS used to encode and modulate the data. The data in the payload may be divided among a plurality of blocks where each block may include a portion of the data and a guard interval (GI) assisting the access point and/or other user device with phase tracking. The frame builder  262  outputs the frame to the transmit processor  264 . 
     The transmit processor  264  processes the frame for transmission. For example, the transmit processor  264  may support different transmission modes such as an OFDM transmission mode and an WB SC transmission mode. In this example, the controller  274  may send a command to the transmit processor  264  specifying which transmission mode to use, and the transmit processor  264  may process the frame for transmission according to the specified transmission mode. The transmit processor  264  may apply a spectrum mask to the frame so that the frequency constituent of the uplink signal meets certain spectral requirements. 
     The transceivers  266 - 1  to  266 -M receive and processes (e.g., converts to analog, amplifies, filters, and frequency upconverts) the output of the transmit processor  264  for transmission via the one or more antennas  270 - 1  to  270 -M. For example, the transceiver  266 - 1  to  266 -M may upconvert the output of the transmit processor  264  to a transmit signal having a frequency in the 60 GHz range. 
     In certain aspects, the transmit processor  264  may support multiple-output-multiple-input (MIMO) transmission. In these aspects, the user device  250  may include multiple antennas  270 - 1  to  270 -M and multiple transceivers  266 - 1  to  266 -M (e.g., one for each antenna). The transmit processor  264  may perform spatial processing on the incoming frame and provide a plurality of transmit frame streams for the plurality of antennas  270 - 1  to  270 -M. The transceivers  266 - 1  to  266 -M receive and process (e.g., converts to analog, amplifies, filters, and frequency upconverts) the respective transmit frame streams to generate distinct spatially-diverse transmit signals for transmission via the antennas  270 - 1  to  270 -M. 
     For receiving data, the access point  212  comprises a receive processor  242 , and a receive data processor  244 . In operation, the transceivers  226 - 1  to  226 -N receive a signal (e.g., from the user device  250 ), and spatially process (e.g., frequency downconverts, amplifies, filters and converts to digital) the received signal. 
     The receive processor  242  receives the outputs of the transceivers  226 - 1  to  226 -N, and processes the outputs to recover data symbols. For example, the access point  212  may receive data (e.g., from the user device  250 ) in a frame. In this example, the receive processor  242  may detect the start of the frame using the legacy STF sequence in the preamble of the frame. The receiver processor  242  may also use the STF for automatic gain control (AGC) adjustment. The receive processor  242  may also perform channel estimation (e.g., using the legacy and/or new protocol CEF in the preamble of the frame) and perform channel equalization on the received signal based on the channel estimation. 
     Further, the receiver processor  242  may estimate phase noise using the guard intervals (GIs) in the payload, and reduce the phase noise in the received signal based on the estimated phase noise. The phase noise may be due to noise from a local oscillator in the user device  250  and/or noise from a local oscillator in the access point  212  used for frequency conversion. The phase noise may also include noise from the channel. The receive processor  242  may also recover information (e.g., MCS scheme) from the header of the frame, and send the information to the controller  234 . After performing channel equalization and/or phase noise reduction, the receive processor  242  may recover data symbols from the frame, and output the recovered data symbols to the receive data processor  244  for further processing. 
     The receive data processor  244  receives the data symbols from the receive processor  242  and an indication of the corresponding MSC scheme from the controller  234 . The receive data processor  244  demodulates and decodes the data symbols to recover the data according to the indicated MSC scheme, and outputs the recovered data (e.g., data bits) to a data sink  246  for storage and/or further processing. 
     As discussed above, the user device  250  may transmit data using an OFDM transmission mode or a WB SC transmission mode. In this case, the receive processor  242  may process the receive signal according to the selected transmission mode. Also, as discussed above, the transmit processor  264  may support multiple-output-multiple-input (MIMO) transmission. In this case, the access point  212  includes multiple antennas  230 - 1  to  230 -N and multiple transceivers  226 - 1  to  226 -N (e.g., one for each antenna). Each transceiver receives and processes (e.g., frequency downconverts, amplifies, filters, frequency upconverts) the signal from the respective antenna. The receive processor  242  may perform spatial processing on the outputs of the transceivers  226 - 1  to  226 -N to recover the data symbols. 
     For receiving data, the user device  250  comprises a receive processor  282 , and a receive data processor  284 . In operation, the transceivers  266 - 1  to  266 -M receive a signal (e.g., from the access point  212  or another user device) via the respective antennas  270 - 1  to  270 -M, and process (e.g., frequency downconverts, amplifies, filters and converts to digital) the received signal. 
     The receive processor  282  receives the outputs of the transceivers  266 - 1  to  266 -M, and processes the outputs to recover data symbols. For example, the user device  250  may receive data (e.g., from the access point  212  or another user device) in a frame, as discussed above. In this example, the receive processor  282  may detect the start of the frame using the legacy STF sequence in the preamble of the frame. The receive processor  282  may also perform channel estimation (e.g., using the legacy and/or the new protocol CEF of the frame) and perform channel equalization on the received signal based on the channel estimation. 
     Further, the receive processor  282  may estimate phase noise using the guard intervals (GIs) in the payload, and reduce the phase noise in the received signal based on the estimated phase noise. The receive processor  282  may also recover information (e.g., MCS scheme) from the header of the frame, and send the information to the controller  274 . After performing channel equalization and/or phase noise reduction, the receive processor  282  may recover data symbols from the frame, and output the recovered data symbols to the receive data processor  284  for further processing. 
     The receive data processor  284  receives the data symbols from the receive processor  282  and an indication of the corresponding MSC scheme from the controller  274 . The receive data processor  284  demodulates and decodes the data symbols to recover the data according to the indicated MSC scheme, and outputs the recovered data (e.g., data bits) to a data sink  286  for storage and/or further processing. 
     As discussed above, the access point  212  or another user device may transmit data using an OFDM transmission mode or a SC transmission mode. In this case, the receive processor  282  may process the receive signal according to the selected transmission mode. Also, as discussed above, the transmit processor  224  may support multiple-output-multiple-input (MIMO) transmission. In this case, the user device  250  may include multiple antennas and multiple transceivers (e.g., one for each antenna). Each transceiver receives and processes (e.g., frequency downconverts, amplifies, filters, frequency upconverts) the signal from the respective antenna. The receive processor  282  may perform spatial processing on the outputs of the transceivers to recover the data symbols. 
     As shown in  FIG. 2B , the access point  212  also comprises a memory  236  coupled to the controller  234 . The memory  236  may store instructions that, when executed by the controller  234 , cause the controller  234  to perform one or more of the operations described herein. Similarly, the user device  250  also comprises a memory  276  coupled to the controller  274 . The memory  276  may store instructions that, when executed by the controller  274 , cause the controller  274  to perform the one or more of the operations described herein. 
     Frame Format Common to the Enhanced Frames 
       FIG. 3A  illustrates a diagram of an exemplary frame or frame portion  300  in accordance with certain aspects of the disclosure. As described herein, all of the frame formats described herein start with the legacy (e.g., 802.11ad) fields: L-STF+L-CEF+L-Header. These fields may be decodable by legacy user devices and new protocol devices (e.g., access points and user devices). After the legacy fields, the transmission includes one or more various fields that may be part of the new protocol (e.g., the currently-being-developed 802.11ay protocol, also known as “NG60”). According to the new protocol, several options may be used: transmission of the frames using orthogonal frequency division multiplexing (OFDM), single carrier wideband (SC WB), single carrier (SC)-Aggregate, wherein each one has various options and formats. All the aforementioned new protocol options start with an Extended Directional Multigigabit (EDMG) Header with optional appended payload data. Legacy devices may not able to decode the EDMG Header, but new protocol devices are able to decode the EDMG Header. 
     According to the diagram, the x- or horizontal axis represents time, and the y- or vertical axis represents frequency. As per the legacy (e.g., 802.11ad) protocol for backwards compatibility purposes, the legacy L-STF portion of the frame  300  may have a duration of 1.16 microseconds (μs), the legacy L-CEF portion may have a duration of 0.73 μs, and the legacy L-Header portion may have a duration of 0.58 μs. The EDMG Header may have a duration of 0.29 μs or more. In the case that the frame  300  is a full frame (not a frame portion), the frame  300  may be transmitted via a single frequency legacy channel and include payload data appended to the EDMG Header. Such configuration may be useful for short messages because there is no need for a separate payload data according to the new frame format, which may consume overhead for the transmission. 
     The legacy L-Header specifies various parameters and may be decoded by all stations (legacy devices, updated legacy devices, new protocol devices, and access points) that are in range. These stations listen when they are waiting to receive a message or prior to transmission. The legacy L-Header specifies the modulation coding scheme (MCS) used in the data transmission and the amount of data that is transmitted. Stations use these two values to compute the entire duration length of any of the new frames described herein (e.g., including the L-STF, L-CES, L-Header, EDMG Header, STF (if included), CEF (if included), and payload data (if included), but excluding the TRN field) to update the network allocation vector (NAV). This is a mechanism that allows stations to know that the medium is going to be used by another device (e.g., an access point or user device), even if they cannot decode the data itself, or even if they are not the intended receiver of the message. The use of NAV is one of the mechanisms to avoid transmitted signal collisions. 
     In the legacy 802.11ad frame format, data is placed in low density parity check (LDPC) blocks, where the size is according to the code rate, then encoded to a fixed length blocks (e.g., 672 bits). The outcome is concatenated and then split into Fast Fourier Transform (FFT) blocks (blocks of modulation symbols) according to the selected MCS (mainly modulation). At a receiver, the process is reversed. It should be noted that in low data MCSs, one LDPC block will require one or more FFT blocks, while in high data MCSs, one FFT block may host more than one LDPC blocks. This discussion is relevant to the placing of LDPC data appended to the EDMG Header, as described in more detail herein. 
       FIG. 3B  illustrates an exemplary EDMG Header  350  of the frame or frame portion  300  in accordance with certain aspects of the present disclosure. The EDMG Header specifies the transmission frame parameters (MCS, Data length, modes, etc.) that are used by a receiver to be able to receive and decode the transmission frame. There is no need for other stations (not the destination station) to demodulate the EDMG Header. Hence, the EDMG Header and appended data can be transmitted at high MCS that is suitable for the destination station. 
     The EDMG Header  350  comprises: (1) a Payload data Length field that may include 24 bits to specify the length of the payload data in octets in all concurrent channels, regardless of whether the payload data is appended to the EDMG Header or in the separate payload data portion; (2) an EDMG Header Number of LDPC blocks field that may include 10 bits to specify the number of LDPC data blocks appended to the EDMG Header. When this value is zero (0), it means there is one (1) LDPC block of data in the EDMG Header; (3) a Spatial streams field that may include 4 bits to represent the number (e.g., 1 to 16) of spatial streams that are being transmitted; (4) a Channels field that may include 3 bits to specify the number of bonded channels (e.g., one (1) to (8) 802.11ad frequency channels (as well as additional channels not available in 802.11ad)); and (5) a Channel offset field that may include 3 bits to specify the offset of the first channel of the bonded channels. In other words, the Channel offset identifies the lowest frequency channel among the bonded channels. This value is set to zero (0) when the first channel is the lowest frequency channel among all the available channels, or when only one channel is used (i.e., no channel bonding). 
     The EDMG Header  350  further comprises: (6) an 11ay MCS field that may include 6 bits to specify the MCS used in the payload data portion of a frame. Note that the data appended to the EDMG Header uses only the legacy 802.11ad MCS (and not the higher MCS that are only available in accordance with the new protocol). The new protocol MCS may include higher throughput modulation schemes beyond those available in 802.11ad, such as 64QAM, 64APSK, 256QAM, and 256 APSK; (7) a GI (Guard Interval) mode field that may include 1 bit to indicate short or long GI. (8) an FFT mode field that may include 1 bit to indicate short or long FFT block. (9) an LDPC mode field that may include 1 bit to signal short or long LDPC block. And (10) a Long CEF field that may include 1 bit that, when set, indicates the use of a long channel estimation sequence for MIMO; in the case that the number of spatial streams is one, this bit is reserved. 
     The EDMG Header  350  further comprises: (11) a Power difference field that may include 4 bits to indicate a difference in average power between the aggregated transmitted power of the legacy portion (L-STF, L-CEF, and L-Header) and EDMG Header of the new frame, and the SC WB transmission portion of the frame (STF+CEF+payload data). This difference may be vendor specific. Some transmitters will need power backoff between the aggregated portion and the SC WB portion due to PA non-linearity. This value will inform the receiver about the expected power difference to assist the automatic gain control (AGC) setup. For example, the value is coded in dB (e.g., 0000: 0 dB, 0100: 4 dB, 1111: 15 dB or above). 
     The EDMG Header  350  further comprises: (12) Reserved bits that may include 22 bits that are reserved at this time. Transmitters should set them to 0 at this time. In the future, these bits may be allocated to various needs; (13) Proprietary bits that may include 8 spare bits that can be used by the vendor and do not require interoperability. Receivers should discard these bits unless they know what they are; and (14) a CRC field that may include 16 bits to sign the EDMG Header. This field is to be used by a receiver to validate the correctness of the received EDMG Header. All bits (except the CRC) shall be used to compute the CRC. 
     The EDMG Header  350  may be sent on each concurrently-transmitted channel having exactly the same content. This duplication can be used by a receiver to increase the correct detection probability. A receiver may use different algorithms: Option1: receiver decodes only one channel (simples but lowest performance); Option2: receiver decodes only one channel at the time. If CRC passes then cease CRC processing for additional channel(s), if not attempt CRC processing for additional channel(s). Option 2 is better at performance than Option 1, but requires serial processing; and Option3: receiver decodes all channels and selects one that has the corrected CRC. Option 3 has the same performance as Option 2, but is faster. 
     Data Appended to the Extended Header 
     Receivers, according to the new protocol, need, from a practical aspect, decode the EDMG Header before samples for the second STF, second CEF, and separate payload data can be received. The reason is that the receiver may need to perform some adjustments. For instance, in SC WB transmission mode, the second STF is transmitted in wideband (WB) mode and the receiver front-end needs to be re-configured with new filters and other parameters. The use of the new protocol modulations require some overhead to be used in some cases (e.g., for processing the second STF and/or second CEF). This overhead reduces the efficiency especially in short messages. 
     Efficient support of the above lead us to suggest to: (1) Use the “spare” period following the EDMG Header to start transmit a particular quantity of payload data to allow the receiver to setup for receiving the SC WB transmission section of the frame; (2) Extend the Data appended to the EDMG Header to at least 2 LDPC blocks and 2 FFT blocks before modulation is changed to the new protocol fields (including the STF and/or the CEF); and an option to extend the data appended to the EDMG Header beyond the minimum (specified above) for improving efficiency for short payload data. 
     EDMG Header shall be sent on each channel used for any transmission, using the legacy 802.11ad MCS specified in the legacy L-header. The EDMG Header may be appended with payload data (if data is to be sent). The data appended to the EDMG Header may be split (distinct) over all used channels. 
     If payload data using the new protocol modulations are used in the transmission, then the EDMG Header and appended data should occupy at least two FFT blocks and at least two LDPC blocks (all this is using the legacy MCS). All LDPC blocks may be fully populated in the EDMG Header. Transmitter may extend this portion to more LDPC blocks, up to 1024 LDPC blocks (per channel, all channels use same legacy MCS). The Length of the data appended to the EDMG Header is according to the number of LDPC blocks (specified in the EDMG Header Number of LDPC blocks field in the EDMG Header per channel) multiplied by number of channels, and amount of bits per LDPC blocks. The length of data in the new protocol payload data field is the rest of the data according to the Length specified in the EDMG Header. 
     If the new protocol modulation is not used in the transmission (e.g., in a short message application), then the EDMG Header and appended payload data (if data is to be sent) should occupy at least one FFT block and at least one LDPC block (all this using the legacy MCS). The payload data should fill the LDPC blocks starting from lowest channel index (e.g., the LDPC block of the lowest-frequency channel is filled first, then the LDPC block of the second lowest-frequency channel is filled, and so on). The Length specified in the EDMG Header refers to the appended payload data that is transmitted following the EDMG Header when no new protocol modulation is used. 
     The transmitter may select more numbers of LDPC blocks in order to optimize the transmission for short packets (avoiding the new protocol sections, such as the second STF and second CEF overhead). Receiver should compare the data length from these LDPC blocks with the Data Length in the EDMG Header to deduce if there is a new protocol payload data section at all, and if yes, to compute the exact amount of data in the new protocol payload data section alone. Note that the LDPC blocks including the EDMG Header and data are fully populated with data if the new protocol payload data exists. 
     The FFT block(s) and LDPC block(s) are per channel. The payload data appended to the EDMG Header is split between the channels evenly starting from lowest channel in a round-robin manner per byte. If the entire payload data cannot be confined to the portion appended to the EDMG Header, then this portion first completely filled before data is sent via new protocol payload data section. The data length in the EDMG Header specifies the actual number of octets, regardless of where they are located (e.g., appended to the EDMG Header or in the new protocol payload data section). 
     The following provides a few non-limiting examples regarding the amount of data available in the data section attached to the EDMG Header for 2 LDPC blocks or 2 FFT blocks: 
     Case 1: 1 channel &amp; legacy MCS-1 (this may be the case of the least data). In MCS-1, two LDPC blocks may be used. These two blocks host 336 bits and will take three FFT blocks to be transmitted. In this example, the information fields (header data) in the EDMG Header occupy 104 bits. Thus, the payload data appended to the EDMG Header is 232 bits (29 bytes) (i.e., 336 bits−104 bits). 
     Case 2: 4 channels and legacy MCS-12 (this may be the case of the most data). In MCS-12, two FFT blocks host 3584 coded bits per channel, that can host 5 LDPC blocks. At this code rate, there are 2520 information bits in the 5 LDPC blocks, out of which 104 header bits will be used for EDMG Header. This leaves 2416 bits for payload data in the EDMG Header per channel Hence, in this case, a total of 1214 payload bytes of data may be transmitted via the EDMG Header of the 4 channels. 
     Case 3: 2 channels and legacy MCS-8 (this may be the case of an intermediate data amount). In MCS-8, two FFT blocks host 1792 coded bits per channel that can hold 2 LDPC blocks. In the two LDPC blocks, there are 1008 information bits, out of which 104 are dedicated to the header information of the EDMG Header. This leaves a total of 904 bits for payload data in the EDMG Header of each channel. For the two channel case, a total of 228 bytes of payload data in the EDMG Headers may be transmitted. 
     Legacy Header Change to Indicate Transmission Mode 
     Bits 44 to 46, which are reserved bits in the legacy (e.g., 802.11ad) L-Header, may be used in the legacy L-Header portion of the new protocol frame to signal transmission mode for the new protocol frame. For example, the legacy L-Header portion signals this as a new protocol frame by setting the 3 bits (e.g., bits 44-46) to any value other than all zeros. An example of the bit values and corresponding modes are indicated in the following table: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Bits 
                 Mode 
               
               
                   
                   
               
             
            
               
                   
                 000 
                 802.11ad (legacy Frame) 
               
               
                   
                 001 
                 SC-WB (New Protocol Frame) 
               
               
                   
                 010 
                 SC-Aggregate (New Protocol Frame) 
               
               
                   
                 011 
                 SC-Duplicate (New Protocol Frame) 
               
               
                   
                 100 
                 OFDM (New Protocol Frame) 
               
               
                   
                 Other 
                 Reserved 
               
               
                   
                   
               
            
           
         
       
     
     Frame Format for OFDM 
       FIGS. 4A-4B  illustrates exemplary frames  400  and  450  for transmission in accordance with an orthogonal frequency division multiplexing (OFDM) transmission mode per another aspect of the disclosure. The OFDM frame format should maintain the legacy 802.11ad preamble (L-STF and L-CEF) and L-Header as prefix in order to be backwards compliant. In addition, OFDM frames  400  and  450  are usually transmitted with some backoff to reduce peak to average power ratio (PARP), which needs to be applied to the legacy preambles themselves. 
     In this example, frame  400  is an example of a two bonded channel OFDM frame in accordance with the new protocol. The frame  400  comprises a first (e.g., 802.11ad) frequency channel (lower channel as shown) for transmitting the legacy preamble (L-STF and L-CEF), the legacy L-Header, and the EDMG Header with the optional appended payload data. The first channel may have a bandwidth of substantially 1.76 GHz. The frame  400  further comprises a second channel (upper channel as shown) for transmitting the legacy preamble (L-STF and L-CEF), legacy L-Header, and the EDMG Header. The transmission of the legacy preamble (L-STF and L-CEF) and legacy L-Header in the first and second channels is for 802.11ad backward compatibility. The payload data appended to the EDMG Header of the first channel may be different than the payload data appended to the EDMG Header of the second channel. The second channel may also have a bandwidth of substantially 1.76 GHz. 
     Additionally, the frame  400  comprises a gap filling (GF) channel situated in frequency between the first and second channels. The GF channel may have a bandwidth of substantially 0.44 GHz. Since the total bandwidth for the transmission is 3.92 GHz, the high frequency portion of the first channel overlaps with the low frequency portion of the GF channel by 20 MHz. Similarly, the high frequency portion of the GF channel overlaps with the low frequency portion of the second channel by 20 MHz. The preamble (STF-GF and CEF-GF) and Header-GF transmitted by way of the GF channel may be configured substantially the same as the legacy preamble (L-STF and L-CEF) and legacy L-Header, but the EDMG Header and appended optional data may not be redundantly transmitted. Legacy devices may not be able to decode the preamble (STF-GF and CEF-GF) and Header-GF transmitted by way of the GF channel, but new protocol devices may decode such fields. The transmission of the legacy preamble and legacy L-Header by way of the first, GF, and second channels are substantially time aligned. Likewise, the transmission of the EDMG Headers by way of the first and second channels is substantially time aligned. 
     The payload data of the frame  400  is transmitted by way of a bonded channel having a frequency band that includes a combination of the frequency bands of the first, GF, and second channels bonded together in frequency. As previously discussed, the transmission of the legacy preamble (L-STF and L-CEF), legacy L-Header, and EDMG Header are transmitted using an MCS specified in the legacy 802.11ad protocol. The data in the payload data field is transmitted using one of the MCS specified in accordance with the new protocol. Since the new protocol includes additional MCS beyond those specified in the legacy 802.11ad, the payload data may be transmitted using an MCS different than the MCS used to transmit the legacy preamble (L-STF and L-CEF), legacy L-Header, and EDMG Header. However, it shall be understood that the MCS used for transmitting the protocol payload data may be the same as the MCS used for transmitting the legacy preamble (L-STF and L-CEF), legacy L-Header, and EDMG Header, as the new protocol may include MCS common with those specified in the legacy protocol (e.g., 802.11ad). 
     The frame  450  is an example of a three channel bonded OFDM frame that is structurally the same as the two channel bonded OFDM frame, but includes an additional third channel and an additional GF channel situated in frequency between the second and third channels. The payload data is transmitted by way of a bonded channel having a frequency band that includes a combination of the frequency bands of the first, first GF, second, second GF, and third channels bonded together. 
     The EDMG Header for the OFDM frames  400  and  450  may be essentially the same as the EDMG Header  350  previously discussed, except that the Power difference field bits are indicated as reserved bits. This may be because OFDM frame may be transmitted with a substantially uniform average power throughout the duration of the frame. 
     Although frames  400  and  450  are examples of two-channel and three-channel bonding, it shall be understood that a frame may be configured in a similar manner to provide more than three bonded channels. 
     Frame Format for SC WB 
       FIGS. 5A-5D  illustrates exemplary frames  500 ,  510 ,  520 , and  530  for transmission using a single carrier wideband (SC WB) transmission mode in accordance with an aspect of the disclosure. 
     The SC WB transmission section includes three (3) subsections that may be present STF, CEF and payload data, and an optional beam training sequence (TRN). The STF is built on Golay codes (as in the legacy L-STF). During this period, a receiver is expected to complete: AGC, timing and frequency acquisition. The STF uses Golay sequences Ga and Gb in the same order as the 802.11ad STF. Optionally, the STF Golay sequence may have a length of 128 (as in 802.11ad) or 256 or 512. 
     The second CEF sequence uses similar Golay sequence construction as the legacy L-CEF of 802.11ad, only replacing the 128-length sequences with 256-length sequences for the two-bonded channel frame  510 , with 512-length sequences for the three-bonded channel frame  520 , and with 1024-length sequences for four (or more)-bonded channel frame  530 . The formats of the Golay sequences of length 256, 512 and 1024 are as follows, using concatenated (II) Ga 128  and Gb 128  sequences from the 802.11ad standard: 
     Ga 256 =[Ga 128 ∥Gb 128 ] and Gb 256 =[Ga 128 ∥−Gb 128 ] 
     Ga 512 =[Ga 256 ∥Gb 256 ] and Gb 512 =[Ga 256 ∥−Gb 256 ] 
     Ga 1024 =[Ga 512 ∥Gb 512 ] and Gb 1024 =[Ga 512 ∥−Gb 512]   
     The payload data is modulated using MSC similar to the 802.11ad with the following changes: (1) In addition to BPSK, QPSK and 16QAM, higher modulations are defined (and can be used): 64QAM, 64APSK, 128APSK, 256QAM, 256APSK; (2) FFT block can be 512 (as in 802.11ad) or 768, 1024, 1536 or 2048; and (3) guard interval (GI) (situated between adjacent FFT blocks) may also be based on Golay code as in 802.11ad, with more length options supported: 32, 64 (as in 802.11ad), 128 or 256. 
     As previously discussed, the beam training sequence (TRN) is optional in all cases. Note that if the SC WB transmission section (second STF, second CEF, payload data, and TRN) is not used, then a TRN field in accordance with 802.11ad may be provided. When the SB WB transmission section is used, then it uses the new protocol (e.g., 802.11ay) TRN options. The new protocol TRN field is built in the same way as the 802.11ad, with options to increase the Golay codes by factor of 2 or 4 (e.g., use Golay sequences of length 256 or 512, instead of 128). 
     With regard to exemplary frame  500 , this case is the extension of the new protocol frame for a single channel. The frame  500  comprises the legacy preamble (L-STF and L-CEF), legacy L-Header, and EDMG Header. The frame  500  facilitates the new MCSs of the new protocol for the transmission of the STF and payload data. Note that second CEF is not present since for a single channel there is no need for re-estimating the channel. The STF is present since a receiver may improve the receiver chain setup for the higher constellations of the new protocol modulation. 
     With regard to exemplary frame  510 , this case is the extension of the new protocol for a two-bonded channel frame. The frame  510  comprises a first frequency channel (lower channel) for transmitting the legacy preamble (L-STF and L-CEF), legacy L-Header, and EDMG Header. The frame  510  further comprises a second frequency channel (upper channel) for transmitting the legacy preamble (L-STF and L-CEF), legacy L-Header, and EDMG Header. Note, that the data appended to the EDMG Header of the first channel may be different than the data appended to the EDMG Header of the second channel. The information fields of the EDMG Header may be configured as per EDMG Header  350  previously discussed. The SC WB transmission section of the frame  510 , namely the STF, CEF, payload data, and optional TRN, are transmitted via a bonded channel having a frequency band comprising at least a portion of each of the frequency bands of the first and second channels. As previously discussed, the transmission of the legacy preamble (L-STF and L-CEF), legacy L-Header, and EDMG Header uses an MCS specified in legacy 802.11ad, and the transmission of the SC WB transmission section uses an MCS specified in the new protocol, both of which may be different. 
     With regard to exemplary frame  520 , this case is the extension of the new protocol frame for a three (3) bonded channel case. With regard to exemplary frame  530 , this case is the extension of new protocol frame for the four (4) bonded channel case. Based on this discussion, it shall be understood that a frame may be configured to have any number of bonded channels. 
     When a station transmits on more than one channel, it may shift the symbol time between channels by any amount of time with the only constrain that the maximum difference between the earliest and latest will not exceed 1 symbol time in 1.76 GHz sampling rate. It means that the maximum difference may be limited to 0.568 nsec. The main reason for doing so is to reduce the aggregated PAPR. The time synchronization between the legacy MCS aggregate section and the SC WB transmission should be kept relative to the first (lowest-frequency) channel. Note that this skew may be used only for SC transmissions and not allowed in OFDM modes. Example: in two channels mode the shift can be ½ symbol, in three channels it can be ⅓ and ⅔ symbols, and in four channels ¼, ½ and ¾ symbols respectively. 
       FIG. 5E  illustrate an exemplary transmission power profile for any of the exemplary frames  510 ,  520 , and  530  in accordance with another aspect of the disclosure. As illustrated, the transmit power level of the SC WB transmission section is greater than (or may be equal to) the transmit power level of the legacy MCS aggregate section. The use of SC WB transmission section and the legacy MCS aggregate section impose different transmitter back-offs due to PAPR differences and practical PAs. For any modulation scheme, one transmission has less PAPR than if the same modulation is used for two or more aggregated signals in order to keep the error vector magnitude (EVM) and/or transmission mask in compliance. It should be noted that different modulations have different PAPR, thus requiring different back-offs. The backoff value is implementation dependent (mainly on the PA). 
     In order to keep the new protocol transmission as efficient as possible in many cases, the legacy aggregate section transmitted in aggregation mode will require a higher backoff. This difference is an issue that may affect the receiver performance. To help receivers mitigate this, it is suggested that two mechanisms one for the legacy receivers and one for the targeted new protocol receiver may be employed. The transmitted power change is at the switch from aggregated section to the SC WB section, as shown in  FIG. 5E . 
     The targeted new protocol receiver usually adjusts the receive chain at the beginning of the legacy L-STF. If there is a power change between the legacy aggregate section and the SC WB transmission section, the receiver may get into saturation. The receiver can adjust the AGC during the STF, but this may reduce the time of other activities like frequency and time acquisition (on the SC WB signal). To help the receiver, the Power difference field in the EDMG Header specifies the power step (e.g., difference between the transmit power levels of the SC WB transmission section and the legacy MCS aggregate section). The receiver may use it to anticipate the required AGC step, thus shortening the second AGC. 
     Legacy receivers (802.11ad) that receive the legacy preamble (L-STF and L-CEF) and L-Header, use these portions to update the NAV as one of the collision avoidance methods. However, these receivers also look at the received power, since in some cases the received power is low enough to allow reuse of the medium. In this case, the power step can mislead some of the receivers if the power is near the border. The update to the legacy header format, as previously mentioned, describes an option to signal the power step. A legacy receiver that can decode these bits (e.g., updated legacy receiver or user device) may act upon it to improve its power estimation. Note that this functionality is not critical for the collision avoidance system, and legacy receivers can operate without it. 
     Since the modes are using most of the reserved bits, and there is some need to have some additional bits (e.g., to signal power step in SC WB mode), the LSBs of the Data Length field may be used for this purpose. In all new protocol modes, the length bits in the legacy L-Header are only used for NAV computation. By using up to 4 bits for all MCSs (and even more if MSC-1 is excluded), the NAV computation is not affected. The 3 LSB bits of the legacy header length are used to signal the difference between the transmit power levels of the legacy aggregate section (L-STF, L-CEF, L-Header and EDMG Header) and the SC WB transmission section (STF, CEF and the payload data) in accordance with the following table: 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Bits 
                 Power difference X [dB] 
               
               
                   
                   
               
             
            
               
                   
                 001 
                 X &lt;= 1 
               
               
                   
                 010 
                 1 &lt; X &lt;= 2.5 
               
               
                   
                 011 
                 2.5 &lt; X &lt;= 4 
               
               
                   
                 100 
                 4 &lt; X &lt;= 5.5 
               
               
                   
                 101 
                 5.5 &lt; X &lt;= 7 
               
               
                   
                 110 
                 7 &lt; X &lt;= 8.5 
               
               
                   
                 111 
                 8.5 &lt; X 
               
               
                   
                   
               
            
           
         
       
     
     Frame Format for Aggregate SC 
       FIGS. 6A-6D  illustrate exemplary frames  600 ,  610 ,  620 , and  630  for transmission via an aggregate single carrier (SC) transmission mode in accordance with an aspect of the disclosure. Transmission in aggregate SC mode is an aggregation of legacy 802.11ad channels. Since the new protocol extends the modes of the 802.11ad, there is a need for EDMG Header bits. 
     The frame formats for both aggregate SC and SC WB (as discussed further herein) are similar in their first section (legacy L-STF, legacy L-CEF, legacy L-Header and EDMG Header), and different for the rest of the transmission. The similar part is kept the same since it is backward compatible with 802.11ad for the backward compatibility feature. It means that legacy (802.11ad) devices will be able to detect it and decode the legacy Header. As previously discussed, this feature allows legacy devices to update the NAV, that is part of the collision avoidance method. Furthermore, in channel bonded (CB) mode, the legacy L-STF, legacy L-CEF, and legacy L-Header are transmitted on all used channels to facilitate legacy devices on all channels to get the NAV. 
     The legacy (L-STF+L-CEF+L-Header) and the EDMG Header should be transmitted with the same power across aggregated channels. However, due to RF impairments, actual effective isotropic radiated power (EIRP) may differ. The EDMG Header is also transmitted in the 802.11ad channels. As previously discussed, the EDMG Header includes information that is part of the new protocol transmission only and also new protocol payload data is appended to the same symbol. The following considerations apply: (1) The legacy L-STF and L-CEF apply (no need for additional CEF); (2) MCS as defined in the legacy Header for 802.11ad apply to the payload data appended to the EDMG Header; (3) payload data appended to the EDMG Header improve overhead for short messages; (4) payload data appended to the EDMG Headers is split across channels in channel bonded (CB) modes to improve overhead; and (5) the average power should be kept the same (means that the power of L-STF, L-CEF, L-Header and EDMG Header are same) in each channel. 
     Frame  600  is an example of the extension of the new protocol for a single channel case. It facilitates the new MCSs of the new protocol for transmission of the payload data and optional TRN. Frame  610  is an example of the extension of the new protocol for a two aggregated channel case. It also facilitates the new MCSs of the new protocol for transmission of the payload data and optional TRN. Frame  620  is an example of the extension of new protocol for a three aggregated channel case. It facilitates the new MCSs of the new protocol for transmission of the payload data and optional TRN. And, frame  630  is an example of the extension of the new protocol for a four aggregated channel case. It facilitates the new MCSs of the new protocol for transmission of the payload data and optional TRN. The EDMG Header and appended payload data are the same as described for the SC WB transmission mode, except that there are no Power difference bits, they instead may be reserved bits. 
     There are two implementation options for the aggregate SC: (1) Each channel is independent; and (2) all channels are mixed. In this first option, each channel is independent. That is, the MCS for the payload data and optional TRN can be different in each channel. The LDPC blocks are confined to one channel, and each channel has its own blocks. Transmitter may assign different power per channel, but the power shall be fixed for the entire transmission. In this case, the EDMG Header can be different in each channel (e.g., different MCS per channel). 
     In this second option, all channels are bonded and mixed. That is, the MCS for the payload data and optional TRN is the same for all channels. The LDPC blocks are spread evenly between the channels. Transmitter may (and should) assign different power per channel to even the detection probability of each channel, but the power shall be fixed during the entire transmission. In this option, the EDMG Header may be the same in each channel. 
     Frame Format for MIMO 
     For MIMO, the legacy sections (L-STF, L-CEF, and L-Header), along with the EDMG Header, are sent in each transmit chain. Similar to 802.11ac, a delay ΔT is inserted between all transmissions of the legacy sections and EDMG Header to prevent unintentional beamforming. In other words, the transmissions of the legacy sections and EDMG Header of the separate transmissions are skewed with respect to each other by the delay ΔT. 
     For MIMO channel estimation, various techniques may be used in order to estimate the channel, without causing too much latency, and keeping substantially the same SNR. First is the use of delay between the sequences. If this delay is substantially 36.4 ns, then channel estimations can be separated at the receiver since the channel delay is no larger than 64 samples at 1.76 GHz. Second is the transmission of multiple orthogonal sequences using mapping orthogonal P-matrix (P HTLTF ) for high throughput long training field (HT-LTF) taken form 802.11mc, section 20.3.9.4.6. Third is the transmission of conjugate vs regular sequence. Forth one is the transmission of multiple orthogonal sequences using mapping P-matrix (P VHTLTF ) for very high throughput long training field (VHT-LTF) as defined in 22.3.8.3.5 in 802.11mc. Fifth, is to increase the length of the channel estimation for increased MIMO estimation accuracy. Increasing the length is done using the techniques above (forth technique), with the same Golay sequences. This option avoids the use of conjugated or delay sequence since it doubles the integration time of the channel estimation. 
     Frame Format for OFDM MIMO 
       FIG. 7  illustrates an exemplary frame  700  for transmission of three (3) spatial transmission streams in a MIMO OFDM signal using channel bonding of three (3) in accordance with an aspect of the disclosure. Each of the spatial transmissions may be configured similar to that of frame  450  previously discussed. It shall be understood that each spatial transmission may include channel bonding of two or more than three. 
     The transmitted legacy section (L-STF, L-CES, and L-Header) and EDMG Header are transmitted with a delay ΔT (e.g., ΔT=36.4 ns) between them to prevent unintentional beamforming. The section of the frame  700  after the EDMG Header may be transmitted in a time aligned MIMO manner That is, the channel estimation section (CEF, CEF-GF, CEF, CEF-GF, and CEF) and payload data of first transmission (TX # 1 ) may be transmitted in a time aligned MIMO (spatial) manner with the channel estimation section (CEF*, CEF*-GF, CEF*, CEF*-GF, and CEF) and payload of second transmission (TX # 1 ), as well as with the channel estimation section (CEF, CEF-GF, CEF, CEF-GF, and CEF) and payload of third transmission (TX # 3 ). 
     Because of the delay ΔT between the respective legacy sections and EDMG headers, and the time alignment of the following sections (CES and payload data), there are gaps between these two parts of the frames in the first and second transmissions TX # 1  and TX # 2 . These gaps are illustrated as shaded boxes for each of the legacy channels and gap filling channels. A transmitter transmitting the frame  700  may insert a dummy signal in each of these gaps to avoid transmission power change within the frame  700 . 
     For the case of MIMO up to 2×2 (two spatial transmission each having a channel bonding of two), this delay is used to estimate the MIMO channel by applying the SISO (legacy) channel estimation sequence of the channel bonding in OFDM. For more than 2 streams, there is a need to include a new channel estimation sequence, which follows the EDMG Header signaling. This channel estimation sequences follow the same format as those for channel bonding, with the additional dimensions added to the estimation using the approaches above. Frame  700  is an example for channel boding of three (3), and MIMO of three (3) spatial transmission streams. 
     Frame Format for WB SC MIMO 
       FIGS. 8A-8C  illustrate exemplary frames  800 ,  820 , and  840  for transmission of two (2), four (4), and eight (8) spatial streams in a MIMO SC WB signal in accordance with an aspect of the disclosure. Each of the spatial transmissions as illustrated in  FIGS. 8A and 8B  may be configured similar to frame  510  previously discussed. It shall be understood that each of the spatial transmission in  FIGS. 8A and 8B  may include a channel bonding of three or more, similar to frames  520  and  530  previously discussed. 
     Similar to frame  700 , because of the beamforming preventing delay ΔT between the respective legacy sections (L-STF, L-CES, and L-Header) and EDMG Header sections of the transmissions TX # 1  and TX # 2  in frame  800  and spatial transmissions TX # 1 , TX # 2 , TX # 3 , and TX # 4  in frame  820 , there are gaps between two parts of the frames in the first transmissions TX # 1  of frame  800 , and in the first, second, and third transmissions TX # 1 , TX # 2 , and TX # 3  of frame  820 . These gaps are illustrated as shaded boxes for each of the legacy channels and gap filling channels. A transmitter transmitting the frame  800  or  820  may insert a dummy signal in each of these gaps to avoid transmission power change within the frame  800  or  820 , respectively. 
     Also, similar to frame  700 , the second STF, second CEF, and payload data of the first and second transmissions TX # 1  and TX # 2  of frame  800  are transmitted in a time aligned MIMO (spatial) manner. In a like manner, the second STF, second CEF, and payload data of the first, second, third, and fourth transmissions TX # 1  to TX # 4  of frame  820  are transmitted in a time aligned MIMO (spatial) manner. 
     Each of the spatial transmissions of frame  840  illustrated in  FIG. 8C  may be configured similar to frame  500 , with the exception that a second (new protocol) CEF and longer sequences thereof (e.g., two concatenated CEF, two concatenated conjugate CEF (CEF*), CEF concatenated with a −CEF, and a CEF* concatenated with a −CEF*). The use of different combinations of CEF, CEF*, −CEF, and −CEF* allow for receivers to differentiate the channel estimations for the different spatial transmissions. Because of the beamforming preventing delay ΔT, transmissions TX # 1  to TX # 7  of frame  840  include dummy signals transmitted in the gaps (shaded area) between the legacy/EDMG section and the following CEF section to avoid transmission power change in the frame  840 . Similarly, the respective CES and payload data sections of the transmissions TX # 1  to TX # 7  of frame  840  are transmitted in a time aligned MIMO (spatial) manner. 
     For SC WB, the transmission is divided into two stages, before the beginning of the second STF and after it. Before the transmission of the second STF, the MIMO transmission includes the legacy L-STF, the legacy L-CEF, the legacy L-Header and the EDMG Header, such that each transmit chain is sending this same signal just delayed by 64 samples at 1.76 GHz (e.g., 36.4 ns) This is done in order to assure no unintentional beamforming is happening. During the L-STF, all transmitting antennas send the same data. Then in the channel estimation field (CEF) time, each antenna is sending different sequence, so to allow the receiver to estimate the entire spatial channel. 
     Frame  800  is an example for a two (2) spatial streams and two (2) channel bonding transmission. Frame  820  is an example for a four (4) spatial streams and 2 channel bonding transmission. Frame  840  is an example for an eight (8) spatial streams and single channel transmission. 
     Frame Format for Aggregate SC MIMO 
       FIGS. 9A-9B  illustrate exemplary frames  900  and  920  for transmission of two (2) and three (3) spatial streams in a MIMO aggregate transmission mode in accordance with an aspect of the disclosure. Each of the spatial transmissions may be configured similar to a two-channel aggregate SC frame, such as frame  610  previously discussed. It shall be understood that each of the spatial transmission may include aggregate channels of less than or more than two. 
     Similarly, each of the spatial transmissions illustrated in  FIG. 9B  may be configured similar to a two-channel aggregate SC frame, such as frame  610 , with the exception that a second (new protocol) CEF and longer sequences thereof (e.g., two concatenated CEF, two concatenated conjugate CEF (CEF*), CEF concatenated with a −CEF, and a CEF* concatenated with a −CEF*). The use of different combinations of CEF, CEF*, −CEF, and −CEF* allow for receivers to differentiate the channel estimations for the different spatial transmissions. 
     MIMO aggregate SC uses the same technique as the SC WB transmission mode, i.e., the three methods, with the difference of the channel estimation in the gap between the band not being transmitted (which is not MIMO related anyway), so the basic sequences are 802.11ad CEF sequences transmitted multiple times. 
     Exemplary frame  900  is an example for the 2 channel bonding with two (2) MIMO spatial transmissions. Then there is no need for adding additional CEF sequence, because the MIMO channel estimation is done using the CEF of the legacy preamble. Exemplary frame  920  is an example for the case of MIMO three (3) spatial transmissions, and then additional CEF sequences are needed in order to estimate the spatial channels. The CEF sequences are like the one used for the SC WB above. Similar to the previous MIMO frames, because of the beamforming preventing delay ΔT, the transmission TX # 1  in frame  900  and transmissions TX # 1  and TX # 2  in frame  920  include dummy signals transmitted in the gaps (shaded area) between the legacy/EDMG section and the following CEF and/or payload data section to avoid transmission power change in the frame  900  or  920 , respectively. 
     Similarly, the respective payload data sections of the transmissions TX # 1  to TX # 2  of frame  900  are transmitted in a time aligned MIMO (spatial) manner. In a like manner, the respective CEF and payload data sections of the transmissions TX # 1  to TX # 3  of frame  920  are transmitted in a time aligned MIMO (spatial) manner. 
       FIG. 10  illustrates an example device  1000  according to certain aspects of the present disclosure. The device  1000  may be configured to operate in an access point or a user device to perform the one or more of the operations described herein. The device  1000  includes a processing system  1020 , and a memory  1010  coupled to the processing system  1020 . The memory  1010  may store instructions that, when executed by the processing system  1020 , cause the processing system  1020  to perform one or more of the operations described herein. Exemplary implementations of the processing system  1020  are provided below. The device  1000  also comprises a transmit/receiver interface  1030  coupled to the processing system  1020 . The interface  1030  (e.g., interface bus) may be configured to interface the processing system  1020  to a radio frequency (RF) front end (e.g., transceivers  226 - 1  to  226 -N,  266 - 1  to  226 -M), as discussed further below. 
     In certain aspects, the processing system  1020  may include one or more of the following: a transmit data processor (e.g., transmit data processor  220  or  260 ), a frame builder (e.g., frame builder  222  or  262 ), a transmit processor (e.g., transmit processor  224  or  264 ) and/or a controller (e.g., controller  234  or  274 ) for performing one or more of the operations described herein. In these aspects, the processing system  1020  may generate a frame and output the frame to an RF front end (e.g., transceiver  226 - 1  to  226 -N or  266 - 1  to  266 -M) via the interface  1030  for wireless transmission (e.g., to an access point or a user device). 
     In certain aspects, the processing system  1020  may include one or more of the following: a receive processor (e.g., receive processor  242  or  282 ), a receive data processor (e.g., receive data processor  244  or  284 ) and/or a controller (e.g., controller  234  and  274 ) for performing one or more of the operations described herein. In these aspects, the processing system  1020  may receive a frame from an RF front end (e.g., transceivers  226 - 1  to  226 -N or  266 - 1  to  266 -M) via the interface  1030  and process the frame according to any one or more of the aspects discussed above. 
     In the case of a user device, the device  1000  may include a user interface  1040  coupled to the processing system  1020 . The user interface  1040  may be configured to receive data from a user (e.g., via keypad, mouse, joystick, etc.) and provide the data to the processing system  1020 . The user interface  1040  may also be configured to output data from the processing system  1020  to the user (e.g., via a display, speaker, etc.). In this case, the data may undergo additional processing before being output to the user. In the case of an access point  212 , the user interface  1040  may be omitted. 
     The various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component(s) and/or module(s), including, but not limited to a circuit, an application specific integrated circuit (ASIC), or processor. Generally, where there are operations illustrated in figures, those operations may have corresponding counterpart means-plus-function components with similar numbering. 
     For instance, some examples of means for generating a frame include the processing system  1020 , Tx frame processing system  202 , frame builder  222 , and frame builder  262 . Some examples of means for outputting the frame for transmission include the transmit/receive interface  1030 , interface  208 , transmit processor  224 , and transmit processor  264 . 
     In some cases, rather than actually transmitting a frame a device may have an interface to output a frame for transmission (a means for outputting). For example, a processor may output a frame, via a bus interface, to a radio frequency (RF) front end for transmission. Similarly, rather than actually receiving a frame, a device may have an interface to obtain a frame received from another device (a means for obtaining). For example, a processor may obtain (or receive) a frame, via a bus interface, from an RF front end for reception. 
     As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like. 
     As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c). 
     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. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     It shall be understood that the processing as described herein may be performed by any digital means as discussed above, and or any analog means or circuitry. 
     The steps of a method or algorithm described in connection with the present disclosure may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in any form of storage medium that is known in the art. Some examples of storage media that may be used include random access memory (RAM), read only memory (ROM), flash memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM and so forth. A software module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across multiple storage media. A storage medium may be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. 
     The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims. 
     The functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in hardware, an example hardware configuration may comprise a processing system in a wireless node. The processing system may be implemented with a bus architecture. The bus may include any number of interconnecting buses and bridges depending on the specific application of the processing system and the overall design constraints. The bus may link together various circuits including a processor, machine-readable media, and a bus interface. The bus interface may be used to connect a network adapter, among other things, to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the case of any of the user devices  106 ,  108 , and  110  (see  FIG. 1 ), a user interface (e.g., keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits such as timing sources, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further. 
     The processor may be responsible for managing the bus and general processing, including the execution of software stored on the machine-readable media. The processor may be implemented with one or more general-purpose and/or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry that can execute software. Software shall be construed broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Machine-readable media may include, by way of example, RAM (Random Access Memory), flash memory, ROM (Read Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof. The machine-readable media may be embodied in a computer-program product. The computer-program product may comprise packaging materials. 
     In a hardware implementation, the machine-readable media may be part of the processing system separate from the processor. However, as those skilled in the art will readily appreciate, the machine-readable media, or any portion thereof, may be external to the processing system. By way of example, the machine-readable media may include a transmission line, a carrier wave modulated by data, and/or a computer product separate from the wireless node, all which may be accessed by the processor through the bus interface. Alternatively, or in addition, the machine-readable media, or any portion thereof, may be integrated into the processor, such as the case may be with cache and/or general register files. 
     The processing system may be configured as a general-purpose processing system with one or more microprocessors providing the processor functionality and external memory providing at least a portion of the machine-readable media, all linked together with other supporting circuitry through an external bus architecture. Alternatively, the processing system may be implemented with an ASIC (Application Specific Integrated Circuit) with the processor, the bus interface, the user interface in the case of an access terminal), supporting circuitry, and at least a portion of the machine-readable media integrated into a single chip, or with one or more FPGAs (Field Programmable Gate Arrays), PLDs (Programmable Logic Devices), controllers, state machines, gated logic, discrete hardware components, or any other suitable circuitry, or any combination of circuits that can perform the various functionality described throughout this disclosure. Those skilled in the art will recognize how best to implement the described functionality for the processing system depending on the particular application and the overall design constraints imposed on the overall system. 
     The machine-readable media may comprise a number of software modules. The software modules include instructions that, when executed by the processor, cause the processing system to perform various functions. The software modules may include a transmission module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. By way of example, a software module may be loaded into RAM from a hard drive when a triggering event occurs. During execution of the software module, the processor may load some of the instructions into cache to increase access speed. One or more cache lines may then be loaded into a general register file for execution by the processor. When referring to the functionality of a software module below, it will be understood that such functionality is implemented by the processor when executing instructions from that software module. 
     If implemented in software, the functions may be stored or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media include both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage medium may be any available medium 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. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared (IR), radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include 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 media may comprise non-transitory computer-readable media (e.g., tangible media). In addition, for other aspects computer-readable media may comprise transitory computer-readable media (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media. 
     Thus, certain aspects may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein. For certain aspects, the computer program product may include packaging material. 
     Further, it should be appreciated that modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by a user terminal and/or base station as applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.), such that a user terminal and/or base station can obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized. 
     It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims.