Patent Description:
Next generation Wireless Local Area Networks (WLANs) will be deployed in high-density environments that include access points (APs) providing wireless access to large numbers of stations (STAs) in the same geographical area. It is desirable for next generation WLANs to simultaneously support various traffic types having diverse quality of service (QoS) requirements, because mobile devices are increasingly used to access streaming video, mobile gaming, and other services. <CIT>, which is relevant as prior art only under Art. <NUM>(<NUM>) EPC to the extend as it claims an earlier priority, discloses methods and apparatuses for communicating over a wireless communication network using a tone allocation unit are disclosed. One method includes determining a total bandwidth for a transmission of a message, the total bandwidth including a plurality of tones. The method further includes logically dividing the plurality of tones in the total bandwidth into one or more <NUM>- or <NUM>-tone groups, each tone group having a number of tones equal to the tone allocation unit. The method further includes determining an indication, the indication assigning one or more of the plurality of tone groups to a wireless communication device of a plurality of wireless communication devices. The method further can include transmitting the indication to the plurality of wireless communication devices. <CIT> (<NUM>-<NUM>-<NUM>) discloses a method for generating OFDM signals implemented in a device operating according to a communication protocol.

Technical advantages are generally achieved, by embodiments of this disclosure which describe a system and method for communicating an orthogonal frequency division multiplexing (OFDM) frame format. The invention provides methods for wireless communication according to claims <NUM> and <NUM>, and apparatuses for wireless communication according to claims <NUM> and <NUM>.

For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:.

It should be understood at the outset that although an illustrative implementation of one or more embodiments are provided below, the disclosed systems and/or methods may be implemented using any number of techniques, whether currently known or not. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims.

Institute of Electrical and Electronics Engineers (IEEE) <NUM>. 11ac defines a WLAN protocol for communicating data over <NUM> GigaHertz (GHz) and <NUM> carrier frequencies, and may be capable of supporting aggregate throughput rates of up to <NUM> Gigabits per second (Gits/s). Even higher throughput rates may be needed to satisfy the performance goals of next-generation WLANs. As a result, IEEE <NUM>. 11ax is being developed as an extension to IEEE <NUM>. 11ac with a goal of providing up to <NUM> GBits over the <NUM> and <NUM> carrier frequencies.

Embodiment tone plans for communicating Orthogonal Frequency Division Multiple Access (OFDMA) frames over <NUM> Megahertz (MHz), <NUM>, and <NUM> channels are provided herein. One or more of the embodiment tone plans may be adopted by IEEE <NUM>. In one embodiment, a Multi-User OFDMA (MU-OFDMA) frame is communicated over a <NUM> channel. A MU-OFDMA frame may carry multiple data streams in different resource units (RUs) to one or more receiving devices. The <NUM> MU-OFDMA frame may include eight <NUM>-tone resource units (RUs), one <NUM>-tone bifurcated RU, and a direct current (DC) region. The eight <NUM>-tone RUs include twenty-six consecutive data and pilot tones, and the bifurcated <NUM>-tone RU is split into two <NUM>-tone portions each of which include thirteen consecutive data and pilot tones. The DC region may include seven null tones. In one example, the DC region of the <NUM> MU-OFDMA frame consists of three DC tones and four null-data tones. Null tones are tones that exclude data, pilot, and control signaling, such as DC tones, guard tones, and/or null-data tones (e.g., data tones that have been re-purposed as null tones). Null tones may be positioned in-between adjacent RUs in an OFDMA frame to mitigate inter-symbol interference in-between the respective data streams carried by the adjacent RUs. Null tones may also be positioned in-between adjacent carriers (e.g., in an edge region) to mitigate inter-carrier interference and to protect RUs near the edge region from distortion due to transmission filtering and other effects. The eight <NUM>-tone RUs, as well as the respective <NUM>-tone portions of the bifurcated RU, are be distributed over two data and pilot regions, and the DC region is positioned in-between those data and pilot regions. In particular, four of the <NUM>-tone RUs and one <NUM>-tone portion of the bifurcated RU may be positioned in one data and pilot region; and the remaining four <NUM>-tone RUs, as well as the other <NUM>-tone portion of the bifurcated RU, may be positioned in the other data and pilot region. Each of the data and pilot regions may be positioned in-between the DC region and a corresponding edge region. One of the edge regions may include a pair of null-data tones and six guard tones. The other edge region may include a pair of null-data tones and five guard tones.

In another embodiment, a MU-OFDMA frame is communicated over an <NUM> channel. The <NUM> MU-OFDMA frame includes thirty-six <NUM>-tone RUs, one <NUM>-tone bifurcated RU, and a DC region consisting of seven DC tones. The RUs may be distributed over two inner-most data and pilot regions and two outer-most data and pilot regions. In one example, nine of the <NUM>-tone RUs and one <NUM>-tone portion of the bifurcated RU are positioned in each of the inner-most data and pilot regions; and nine of the <NUM>-tone RUs are positioned in each of the outer-most data and pilot regions. The DC region may be positioned in-between the inner-most data and pilot regions, and each one of the outer-most data and pilot regions may be positioned in-between a respective one of the inner-most data and pilot regions and a corresponding edge region. One of the edge regions may include a set of eight null-data tones and twelve guard tones. The other edge region may include a set of eight null-data tones and eleven guard tones. In some embodiments, a set of eight null-data tones is positioned in-between each inner-most data region and the corresponding outer-most data and pilot region. In such embodiments, the <NUM> MU-OFDMA frame may carry thirty-six null-data tones.

In another embodiment, a Single User OFDMA (SU-OFDMA) frame is communicated over an <NUM> channel. A SU-OFDMA frame may carry a single data stream to a receiving device. In one example, the <NUM> SU-OFDMA frame includes <NUM> data and pilot tones, a <NUM>-tone bifurcated RU, and seven DC tones. The <NUM> data and pilot tones are distributed over two inner-most data and pilot regions and two outer-most data and pilot regions. The two inner-most data and pilot regions each carry <NUM> consecutive data and pilot tones and one <NUM>-tone portion of the bifurcated RU. The two outer-most data and pilot regions each carry <NUM> consecutive data and pilot tones. Similar to the <NUM> MU-OFDMA frame, the DC region in the <NUM> SU-OFDMA frame may be positioned in-between the inner-most data and pilot regions. Each one of the outer-most data and pilot regions in the <NUM> SU-OFDMA frame may be positioned in-between a respective one of the inner-most data and pilot regions and a corresponding edge region. One of the edge regions may include twelve guard tones, and the other edge region includes eleven guard tones. These and other aspects are described in greater detail below.

<FIG> illustrates a network <NUM> for communicating data. The network <NUM> comprises an access point (AP) <NUM> having a coverage area <NUM>, a plurality of mobile stations <NUM>, and a backhaul network <NUM>. As shown, the AP <NUM> establishes uplink (dashed line) and/or downlink (dotted line) connections with the mobile stations <NUM>, which serve to carry data from the mobile stations <NUM> to the AP <NUM> and vice-versa. Data carried over the uplink/downlink connections may include data communicated between the mobile stations <NUM>, as well as data communicated to/from a remote-end (not shown) by way of the backhaul network <NUM>. As used herein, the term "access point (AP)" refers to any component (or collection of components) configured to provide wireless access to a network, such as an enhanced base station (eNB), a macro-cell, a femtocell, a Wi-Fi access point (AP), or other wirelessly enabled devices. APs may provide wireless access in accordance with one or more wireless communication protocols, e.g., Wi-Fi <NUM>. 11a/b/g/n/ac/ax, long term evolution (LTE), LTE advanced (LTE-A), High Speed Packet Access (HSPA), etc. As used herein, the term "mobile station" refers to any component (or collection of components) capable of establishing a wireless connection with an AP, such as a station (STA), a user equipment (UE), and other wirelessly enabled devices. In some embodiments, the network <NUM> may comprise various other wireless devices, such as relays, low power nodes, etc..

<FIG> is a diagram of an embodiment frame structure for a downlink (DL) OFDM frame <NUM>. As shown, the downlink OFDM frame <NUM> includes a legacy short training field (L-STF)/long training field (LTF) <NUM>, a legacy signaling field (L-SIG)/repeated legacy (RL) SIG field <NUM>, a high efficiency (HE) first signal (SIGA) field <NUM>, a HE second signal (SIGB) field <NUM>, a HE-STF/LTF field <NUM>, and a data payload field <NUM>. Scheduling index information is embedded in the SIGB field <NUM>. The index information associates identifiers (IDs) assigned to individual STAs or groups of STAs, with starting or ending positions for subsets of assigned RUs in a sequence of RUs carried by the OFDM frame. For example, the scheduling index information may indicate a leading RU and/or trailing RU in a subset of RUs allocated to a STA, and may enable the STA to locate the subset of allocated RUs upon receiving the frame.

<FIG> is a diagram of an embodiment tone plan for a MU-OFDMA frame <NUM> that is communicated over a <NUM> channel. As shown, the MU-OFDMA frame <NUM> includes eight <NUM>-tone RUs <NUM>, two portions <NUM>, <NUM> of a bifurcated <NUM>-tone RU, null-data tones <NUM>, and DC tones <NUM>. In this example, three DC tones <NUM> and four null-data tones <NUM> are included in a DC region <NUM>. Four of the <NUM>-tone RUs <NUM> and one portion <NUM> of the bifurcated RU are included in the data and pilot region <NUM>, and four of the <NUM>-tone RUs <NUM> and the remaining portion <NUM> of the bifurcated RU are included in the data and pilot region <NUM>. The DC region <NUM> is positioned in-between the data and pilot region <NUM> and the data and pilot region <NUM>. Two of the null-data tones <NUM> are included in an edge region <NUM> and two of the null-data tones <NUM> are positioned in an edge region <NUM>. Additionally, six guard tones <NUM> are included in the edge region <NUM>, and the five guard tones <NUM> are included in the edge region <NUM>. In some embodiments, the guard tones <NUM> are included within the <NUM> channel over which MU-OFDMA frame <NUM> is transmitted. In other embodiments, the guard tones <NUM> tones that are outside the <NUM> channel over which the ME-OFDMA frame <NUM> is transmitted.

<FIG> is a diagram of an embodiment tone plan for a SU-OFDMA frame <NUM> that is communicated over a <NUM> channel. As shown, the SU-OFDMA frame <NUM> includes data and pilot regions <NUM>, <NUM> and DC tones <NUM>. In this example, the data and pilot regions <NUM>, <NUM> each include one-hundred and twenty-one consecutive data and pilot tones. The DC tones <NUM> are positioned in-between the data and pilot regions <NUM>, <NUM>. The data and pilot region <NUM> is positioned in-between six guard tones <NUM> and the DC tones <NUM>. The data and pilot region <NUM> is positioned in-between the DC tones <NUM> and five guard tones <NUM>. In some embodiments, the guard tones <NUM> are included within the <NUM> channel over which the SU-OFDMA frame <NUM> is transmitted. In other embodiments, the guard tones <NUM> are positioned outside the <NUM> channel over which the SU-OFDMA frame <NUM> is transmitted.

Embodiments of this disclosure provide tone plans for OFDMA frames communicated over <NUM> channels. <FIG> is a diagram of an embodiment tone plan for a MU-OFDMA frame <NUM> that is communicated over a <NUM> channel. As shown, the MU-OFDMA frame <NUM> includes eighteen <NUM>-tone RUs <NUM>, null-data tones <NUM>, and DC tones <NUM>. Five DC tones <NUM> and eight null-data tones <NUM> are included in a DC region <NUM>. Nine of the <NUM>-tone RUs <NUM> are included in a data and pilot region <NUM>, and nine of the <NUM>-tone RUs <NUM> are included in a data and pilot region <NUM>. The DC region <NUM> is positioned in-between the data and pilot region <NUM> and the data and pilot region <NUM>. Four null-data tones <NUM> are included in an edge region <NUM>, and four null-data tones <NUM> are included in an edge region <NUM>. Additionally, twelve guard tones <NUM> are included in the edge region <NUM>, and the eleven guard tones <NUM> are included in the edge region <NUM>. In some embodiments, the guard tones <NUM> are included within the <NUM> channel over which the MU-OFDMA frame <NUM> is transmitted. In other embodiments, the guard tones <NUM> tones are outside the <NUM> channel over which the MU-OFDMA frame <NUM> is transmitted.

<FIG> is a diagram of an embodiment tone plan for a SU-OFDMA frame <NUM> that is communicated over a <NUM> channel. As shown, the SU-OFDMA frame <NUM> includes data and pilot regions <NUM>, <NUM> and DC tones <NUM>. In this example, the data and pilot regions <NUM>, <NUM> each include two-hundred and forty-two consecutive data and pilot tones. The DC tones <NUM> are positioned in-between the data and pilot regions <NUM>, <NUM>. The data and pilot region <NUM> is positioned in-between twelve guard tones <NUM> and the DC tones <NUM>. The data and pilot region <NUM> is positioned in-between the DC tones <NUM> and eleven guard tones <NUM>. In some embodiments, the guard tones <NUM> are included within the <NUM> channel over which the SU-OFDMA frame <NUM> is transmitted. In other embodiments, the guard tones <NUM> tones are outside the <NUM> channel over which the SU-OFDMA frame <NUM> is transmitted.

Embodiments of this disclosure provide tone plans for OFDMA frames communicated over <NUM> channels. <FIG> is a diagram of an embodiment tone plan for a MU-OFDMA frame <NUM> that is communicated over an <NUM> channel. As shown, the MU-OFDMA frame <NUM> includes <NUM>-tone RUs <NUM>, portions <NUM>, <NUM> of a bifurcated <NUM>-tone RU, null-data tones <NUM>, and five DC tones <NUM>. In this example, the <NUM>-tone RUs <NUM> and the portions <NUM>, <NUM> of the bifurcated RU are distributed over four data and pilot regions <NUM>, <NUM>, <NUM>, <NUM>. In particular, the data and pilot region <NUM> includes nine <NUM>-tone RUs <NUM> and one portion <NUM> of the bifurcated RU, and the data and pilot region <NUM> includes nine <NUM>-tone RUs <NUM> and the remaining portion <NUM> of the bifurcated RU. The four data and pilot regions <NUM>, <NUM> each include nine <NUM>-tone RUs <NUM>. The DC region <NUM> is positioned in-between the data and pilot region <NUM> and the data and pilot region <NUM>. The data and pilot region <NUM> is positioned in-between the DC region and the data and pilot region <NUM>, and the data and pilot region <NUM> is positioned in-between the DC region and the data and pilot region <NUM>. The data and pilot region <NUM> is positioned in-between the data and pilot region <NUM> and an edge region <NUM>, and the data and pilot region <NUM> is positioned in-between the data and pilot region <NUM> and an edge region <NUM>. Because of their relative positioning with respect to one another, the data and pilot regions <NUM>, <NUM> may be referred to herein as the inner-most data and pilot regions of the MU-OFDMA frame <NUM>, and the data and pilot regions <NUM>, <NUM> may be referred to herein as the outer-most data and pilot regions of the MU-OFDMA frame <NUM>. Eight null-data tones <NUM> are included in an edge region <NUM>, and eight null-data tones <NUM> are included in an edge region <NUM>. Additionally, thirteen guard tones <NUM> are included in the edge region <NUM>, and twelve guard tones <NUM> are included in the edge region <NUM>. In some embodiments, the guard tones <NUM> are included within the <NUM> channel over which the MU-OFDMA frame <NUM> is transmitted. In other embodiments, the guard tones <NUM> tones are outside the <NUM> channel over which the MU-OFDMA frame <NUM> is transmitted. Eight null-data tones <NUM> are positioned in-between the data and pilot region <NUM>, <NUM>. Similarly, eight null-data tones <NUM> are positioned in-between the data and pilot region <NUM>, <NUM>.

<FIG> is a diagram of an embodiment tone plan for a SU-OFDMA frame <NUM> that is communicated over an <NUM> channel. As shown, the SU-OFDMA frame <NUM> includes data and pilot regions <NUM>, <NUM>, <NUM>, <NUM>, portions <NUM>, <NUM> of a bifurcated <NUM>-tone RU, and five DC tones <NUM>. In this example, the data and pilot regions <NUM>, <NUM>, <NUM>, <NUM> each include two-hundred and forty-two consecutive data and pilot tones. The five DC tones <NUM> are positioned in-between the data and pilot regions <NUM>, <NUM>. The data and pilot regions <NUM>, <NUM> are positioned in-between twelve guard tones <NUM> and the DC tones <NUM>. The data and pilot region <NUM>, <NUM> are positioned in-between the DC tones <NUM> and eleven guard tones <NUM>. In some embodiments, the guard tones <NUM> are included within the <NUM> channel over which the SU-OFDMA frame <NUM> is transmitted. In other embodiments, the guard tones <NUM> tones are outside the <NUM> channel over which the SU-OFDMA frame <NUM> is transmitted.

<FIG> is a diagram of an embodiment tone plan for a MU-OFDMA frame <NUM> that is communicated over an <NUM> channel. The RUs <NUM>, <NUM>, <NUM>, tones <NUM>, <NUM>, <NUM>, and regions <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> in the MU-OFDMA frame <NUM> have similar arrangements and configurations to like components/regions of the MU-OFDMA frame <NUM>, except that the DC region <NUM> includes seven DC tones <NUM>, the edge region <NUM> includes twelve guard tones <NUM>, and the edge region <NUM> includes eleven guard tones <NUM>.

<FIG> is a diagram of an embodiment tone plan for a SU-OFDMA frame <NUM> that is communicated over an <NUM> channel. The data and pilot regions in the SU-OFDMA frame <NUM> have similar arrangements and configurations to like components/regions of the SU-OFDMA frame <NUM>, except that the DC region <NUM> includes seven DC tones <NUM>, as well as that there are twelve guard tones <NUM> positioned outside of the data and pilot region <NUM> and eleven guard tones <NUM> positioned outside of the data and pilot region <NUM>.

Aspects of this disclosure provide embodiment frame formats for use in a wireless environment such as an Institute of Electrical and Electronics Engineers (IEEE) <NUM>. 11ax network. Embodiments provide tone plans for the orthogonal frequency division multiple access (OFDMA) resource units (RUs) for <NUM>, <NUM>, and <NUM> OFDMA transmissions. An embodiment at <NUM> includes <NUM> null tones on one edge of an orthogonal frequency division multiplexing (OFDM) frame, <NUM> null tones on the other edge of the OFDM frame, and three null tones in a direct current (DC) region. An embodiment OFDM frame for <NUM> has <NUM> x <NUM> = <NUM> data and pilot tones grouped in RUs, with additional null tones in the DC region and on the edges. Single user (SU) frames are scheduled for a single user. Multi-user OFDMA frames can be scheduled for multiple users. In other embodiments, for <NUM> OFDM transmission, there are either <NUM> null tones in the DC region or <NUM> null tones in the DC region. In another embodiment, <NUM>, <NUM>, and <NUM> OFDMA tone plans use <NUM>-tone RUs, and <NUM> SU scheduling uses <NUM>-tone RUs. The OFDMA or SU frame may be a downlink frame or an uplink frame.

In an embodiment OFDM frame, there are <NUM> leftover tones within each <NUM> tone block. Leftover tones may be used as separators between different RUs, especially smaller size RUs, to reduce leakage from adjacent blocks. Additional null tones near the edge may be used for protection from pulse shaping filters, adjacent blockers, etc. No data is transmitted on the leftover tones, DC tones, or edge tones. That is, leftover tones, DC tones, and edge tones are all null tones. Leftover tones may be adjacent to edge tones, in which case the number of null tones near the edge is equal to the sum of the number of edge tones and the number of leftover tones adjacent to the edge tones. Also, leftover tones may be adjacent to the DC tones, in which case the number of null tones in the DC region is equal to the sum of the number of DC tones and the number of leftover tones adjacent to the DC region. Edge tones may also be known as guard tones.

There are several factors which may be considered in determining tone plans and RU allocation. RUs may be aligned between <NUM>, <NUM>, and <NUM> frame configurations. Null tones in the DC regions and null tones at the edges may be allocated based on spectral mask and carrier frequency offset (CFO) requirements to protect tones in RUs near the edge tones and the DC tones. Other considerations in determining tone plans and RU allocations include the utilization of leftover tones, for example, to align the RUs and protect tones in RUs near DC tones and edge tones. Edge tones, DC tones, and leftover tones are null tones, and are not used for transmitting data or pilots.

Distortion may affect tones in RUs near the edges of OFDMA frames more significantly than tones in RUs near the edges of SU frames. In one example, the tone plans used for both SU frames and OFDMA frames are similar. Alternatively, the tone for for SU frames and OFDMA frames are different. In one example, additional null tones are used in OFDMA frames to provide additional protection for RUs near the edge and in the DC region. Thus, an OFDMA frame may have more null tones near the edge and null tones in the DC region compared to an SU frame. Null tones near the edge are positioned at the edges of the transmission bands as guard tones to mitigate the effect of transmission filtering on the data and pilot tones. Null tones in the DC region are empty subcarriers (i.e. subcarriers that do not carry data/information) that are used by mobile devices to locate the center of the OFDM frequency band.

Embodiments provide tone plans for <NUM> and <NUM> OFDM frames. In some embodiments, <NUM> DC tones are used, for example with <NUM> ppm CFO. In other embodiments, for example with <NUM>, <NUM> DC tones or <NUM> DC tones may be used. In various embodiments, the null tones are utilized to align the RUs and to protect tones near the DC region and the edge.

In an embodiment <NUM> tone plan there are <NUM><NUM>-tone RUs containing data and pilot tones, and <NUM> tones allocated for null tones in the DC region and null tones near the edge. In one example, there are <NUM> null tones in the DC region and [<NUM>,<NUM>] null tones near the edges. The notation [A, B] denotes A edge tones on one edge of an OFDM frame and B edge tones on the other edge of the OFDM frame. In an embodiment <NUM> tone plan, there are [<NUM>,<NUM>] null tones near the edges and <NUM> null tones in the DC region. In another embodiment <NUM> tone plan, there are [<NUM>,<NUM>] null tones near the edges and <NUM> null tones in the DC region. There may be <NUM> tones for data, pilots, and leftover tones. In one embodiment, the tone plan is the same for SU frames and OFDMA frames. Alternatively, the tone plan for SU frames is different than the tone plan for OFDMA frames.

Before frames are transmitted, transmission filtering may be performed. The transmission filter may be based on the spectral mask. Leftover tones may be used to protect RUs near null tones at the edges and null tones in the DC region.

In OFDMA, different RUs are allocated to different STAs. Any number of RUs may be allocated for a particular STA. Each STA estimates the channel and recovers the entire message. The signaling field is used by each STA to determine which RU(s) are allocated to that particular STA.

<FIG> illustrates a tone plan <NUM> for a <NUM> OFDMA frame. There are a total of <NUM> data, pilot, and leftover tones. Leftover tones are used for the protection of RUs near the DC tones and edge tones, to increase the number of null tones in the DC region and the number of null tones near the edges. A leftover tone used to protect the RUs near the DC tones increases the number of null tones in the DC region. Also, a leftover tone used to protect the RUs near the edge tones increases the number of null tones near the edges. DC tones, edge tones, and leftover tones are all null tones. The tones in RUs <NUM> include data and pilot tones, and the tones <NUM>, <NUM>, and <NUM> are the leftover tones, which are null tones. Pilot tones may be distributed throughout the RUs in the tones in RUs <NUM>. The separate pilot tones carried by an RU may be used to adjust or estimate the phase and/or frequency offsets of data tones carried in the RU. For example, in an uplink OFDMA frame carrying RUs transmitted by different STAs, the pilot tones carried in the respective RUs may be used by a serving AP to perform residual carrier frequency offset estimation on the uplink OFDMA frame. There are <NUM> data and pilot tones, including the <NUM><NUM>-tone RUs <NUM> and the <NUM>-tone RU <NUM> that is split into <NUM> tones on each side of the null tones in the DC region <NUM>. There are <NUM> leftover tones, which are used to protect RUs near edge tones and DC tones. Two of the leftover tones <NUM> are used on each side of the DC tones <NUM>. The two leftover tones <NUM> are placed adjacent to the <NUM> edge tones <NUM>, for <NUM> null tones near the edge <NUM>. Also, the two leftover tones <NUM> are adjacent to the <NUM> edge tones <NUM> for <NUM> null tones near the edge <NUM>.

<FIG> illustrates tone plans <NUM> for a <NUM> transmission for OFDMA and SU frames. There are <NUM> tones for data, pilot, and leftover tones, and <NUM> tones for DC and edge tones. Tone plans <NUM> includes the OFDMA tone plan <NUM> and the SU tone plan <NUM>. The tones in the OFDMA tone plan <NUM> are sent to or received from multiple STAs. The tones in the SU tone plan <NUM> are sent to or received from a single STA.

The SU tone plan <NUM> includes the <NUM> DC tones <NUM>. The <NUM> DC tones <NUM> are included in a DC region. On each side of the DC tones <NUM> is a <NUM>-tone RU <NUM>. Each <NUM>-tone RU includes <NUM> pilot tones and <NUM> data tones. One edge includes <NUM> edge tones <NUM>. The other edge includes <NUM> edge tones <NUM>.

RUs and leftover tones of the OFDMA tone plan <NUM> are aligned with RUs of the SU tone plan <NUM>. The OFDMA tone plan <NUM> includes <NUM> DC tones <NUM>. Four leftover tones <NUM> are on each side of the DC tones <NUM> for <NUM> null tones in the DC region <NUM> to protect the RUs near the null tones in the DC region <NUM>. On one edge there are <NUM> edge tones <NUM>. Four leftover tones <NUM> are adjacent to edge tones <NUM> for <NUM> null tones near the edge <NUM>. On the other edge are <NUM> edge tones <NUM> and four leftover tones <NUM> adjacent to the edge tones <NUM> for <NUM> null tones near the edge <NUM>. The <NUM> data and pilot tones are distributed over <NUM><NUM>-tone RUs. Nine of the <NUM>-tone RUs are positioned on each side of the DC region <NUM>. Each <NUM>-tone RU includes <NUM> pilot tones and <NUM> data tones.

<FIG> illustrates the <NUM> tone plans <NUM> for OFDMA and SU frames. There are <NUM> data, pilot, and leftover tones, and <NUM> DC and edge tones. The tone plans <NUM> include the OFDMA tone plan <NUM> and the SU tone plan <NUM>. The tones in the OFDMA tone plan <NUM> are sent to or received from multiple STAs. The tones in the SU tone plan <NUM> are sent to or received from a single STA. The RUs for the OFDMA tone plan <NUM> are aligned with the RUs of the SU tone plan <NUM>.

The SU tone plan <NUM> contains <NUM> DC tones <NUM>. The RU <NUM> is split into two <NUM>-tone portions. The five DC tones <NUM> are positioned in-between the respective <NUM>-tone portions of the RU <NUM>. The tones in RU <NUM> include two sets of <NUM>-tone RUs on each side, for <NUM><NUM>-tone RUs. <NUM> edge tones <NUM> are at one edge and <NUM> edge tones <NUM> are at the opposite edge.

RUs, DC tones, and edge tones of the OFDMA tone plan <NUM> are aligned with RUs, DC tones, and edge tones of the SU tone plan <NUM>, respectively. There are <NUM> pilot and data tones in the OFDMA tone plan <NUM>, grouped into <NUM><NUM>-tone RUs. The OFDMA tone plan <NUM> includes <NUM> DC tones <NUM>, which are aligned with DC tones <NUM>. There are a total of <NUM> null tones in the DC region. Also, the OFDMA tone plan <NUM> includes <NUM> edge tones <NUM>. <NUM> leftover tones <NUM> are adjacent to the edge tones <NUM>, for a total of <NUM> null tones at the edge <NUM>. Also, OFDMA tone plan <NUM> contains <NUM> edge tones <NUM>. The leftover tones <NUM> are adjacent to the edge tones <NUM>, for a total of <NUM> null tones near the edge <NUM>. The <NUM>-tone RU <NUM> is split by DC tones <NUM>, with <NUM> tones on each side of DC tones <NUM>. There are four sets of <NUM><NUM>-tone RUs <NUM>, <NUM>, <NUM>, and <NUM>. The leftover tones include the tones <NUM>, <NUM>, <NUM>, <NUM>. The tones <NUM> and <NUM> are between sets of <NUM><NUM>-tone RUs.

<FIG> illustrates <NUM> tone plans <NUM> for OFDMA frames and SU frames. There are <NUM> data, pilot, and leftover tones, and <NUM> DC and edge tones. The tone plans <NUM> include the OFDMA tone plan <NUM> and the SU tone plan <NUM>. The tones in the OFDMA tone plan <NUM> are sent to or received from multiple STAs. The tones in the SU tone plan <NUM> are sent to or received from a single STA. The RUs, DC tones, and edge tones of the OFDMA tone plan <NUM> are aligned with the RUs, DC tones, and edge tones of the SU tone plan <NUM>, respectively.

The SU tone plan <NUM> contains <NUM> DC tones <NUM>. There are a total of <NUM> null tones in the DC region. Also, the RU <NUM> includes two <NUM>-tone portions. The DC tones <NUM> are positioned in-between the respective <NUM>-tone portions of the RU <NUM>. The RUs <NUM> include two sets of <NUM>-tone RUs on each side of the DC tones <NUM> and the RU <NUM>. <NUM> edge tones <NUM> are at one edge, for a total of <NUM> null tones at that edge, and <NUM> edge tones <NUM> are at the opposite edge, for <NUM> null tones at that edge.

The OFDMA tone plan <NUM> is aligned with the SU tone plan <NUM>. There are a total of <NUM><NUM>-tone RUs in the OFDMA tone plan <NUM>. The OFDMA tone plan <NUM> includes <NUM> DC tones <NUM>, for a total of <NUM> null tones in the DC region. Also, the OFDMA tone plan <NUM> includes <NUM> edge tones <NUM> and <NUM> edge tones <NUM>. The leftover tones include four sets of eight tones <NUM>, <NUM>, <NUM>, and <NUM>. The <NUM> tones <NUM> are adjacent to edge tones <NUM>, for <NUM> null tones at the edge <NUM>. Also, <NUM> leftover tones <NUM> are adjacent to edge tones <NUM>, for <NUM> null tones at the edge <NUM>. The tones <NUM> and the tones <NUM> are between sets of <NUM><NUM>-tone RUs. The <NUM> tones <NUM> include <NUM> tones on each side of the DC tones <NUM>. There are four sets of <NUM><NUM>-tone RUs <NUM>, <NUM>, <NUM>, and <NUM>.

In another embodiment, there are a total of <NUM><NUM>-tone RUs. One of the <NUM>-tone RUs may be used for scheduling STAs.

Additional examples may include different sized RUs. For example, RUs may contain <NUM> tones, <NUM> tones, <NUM> tones, <NUM> tones, or another number of tones.

For a downlink frame based on the signaling field of the frame, the receiver determines which RUs are scheduled for that STA. The receiver may perform CFO estimation using the pilots. Residual frequency offset compensation may include estimating a carrier frequency offset based on dedicated pilots carried in OFDMA transmission.

Embodiments include tone plans for <NUM> and <NUM> OFDMA transmissions. In one embodiment, the OFDMA tone plan is the same as or similar to the SU tone plan. Alternatively, the OFDMA tone plan is different than the SU tone plan. In an embodiment, there are <NUM> DC tones for <NUM> ppm CFO. In an embodiment, <NUM>-tone RUs for OFDMA frames are aligned with <NUM>-tone RUs for SU frames, and one RU does not overlap the position of another RU. In an embodiment, leftover tones are utilized to align RUs and protect tones near DC tones and edge tones. In an embodiment, one <NUM>-tone RU is used for scheduling in <NUM>.

<FIG> a block diagram of an embodiment processing system <NUM> for performing methods described herein, which may be installed in a host device. As shown, the processing system <NUM> includes a processor <NUM>, a memory <NUM>, and interfaces <NUM>-<NUM>, which may (or may not) be arranged as shown in <FIG>. The processor <NUM> may be any component or collection of components adapted to perform computations and/or other processing related tasks, and the memory <NUM> may be any component or collection of components adapted to store programming and/or instructions for execution by the processor <NUM>. In an embodiment, the memory <NUM> includes a non-transitory computer readable medium. The interfaces <NUM>, <NUM>, <NUM> may be any component or collection of components that allow the processing system <NUM> to communicate with other devices/components and/or a user. For example, one or more of the interfaces <NUM>, <NUM>, <NUM> may be adapted to communicate data, control, or management messages from the processor <NUM> to applications installed on the host device and/or a remote device. As another example, one or more of the interfaces <NUM>, <NUM>, <NUM> may be adapted to allow a user or user device (e.g., personal computer (PC), etc.) to interact/communicate with the processing system <NUM>. The processing system <NUM> may include additional components not depicted in <FIG>, such as long term storage (e.g., non-volatile memory, etc.).

In some embodiments, the processing system <NUM> is included in a network device that is accessing, or part otherwise of, a telecommunications network. In one example, the processing system <NUM> is in a network-side device in a wireless or wireline telecommunications network, such as a base station, a relay station, a scheduler, a controller, a gateway, a router, an applications server, or any other device in the telecommunications network. In other embodiments, the processing system <NUM> is in a user-side device accessing a wireless or wireline telecommunications network, such as a mobile station, a user equipment (UE), a personal computer (PC), a tablet, a wearable communications device (e.g., a smartwatch, etc.), or any other device adapted to access a telecommunications network.

In some embodiments, one or more of the interfaces <NUM>, <NUM>, <NUM> connects the processing system <NUM> to a transceiver adapted to transmit and receive signaling over the telecommunications network. <FIG> illustrates a block diagram of a transceiver <NUM> adapted to transmit and receive signaling over a telecommunications network. The transceiver <NUM> may be installed in a host device. As shown, the transceiver <NUM> comprises a network-side interface <NUM>, a coupler <NUM>, a transmitter <NUM>, a receiver <NUM>, a signal processor <NUM>, and a device-side interface <NUM>. The network-side interface <NUM> may include any component or collection of components adapted to transmit or receive signaling over a wireless or wireline telecommunications network. The coupler <NUM> may include any component or collection of components adapted to enable bi-directional communication over the network-side interface <NUM>. The transmitter <NUM> may include any component or collection of components (e.g., up-converter, power amplifier, etc.) adapted to convert a baseband signal into a modulated carrier signal suitable for transmission over the network-side interface <NUM>. The receiver <NUM> may include any component or collection of components (e.g., down-converter, low noise amplifier, etc.) adapted to convert a carrier signal received over the network-side interface <NUM> into a baseband signal. The signal processor <NUM> may include any component or collection of components adapted to convert a baseband signal into a data signal suitable for communication over the device-side interface(s) <NUM>, or vice-versa. The device-side interface(s) <NUM> may include any component or collection of components adapted to communicate data-signals between the signal processor <NUM> and components within the host device (e.g., the processing system <NUM>, local area network (LAN) ports, etc.).

The transceiver <NUM> may transmit and receive signaling over any type of communications medium. In some embodiments, the transceiver <NUM> transmits and receives signaling over a wireless medium. For example, the transceiver <NUM> may be a wireless transceiver adapted to communicate in accordance with a wireless telecommunications protocol, such as a cellular protocol (e.g., long-term evolution (LTE), etc.), a wireless local area network (WLAN) protocol (e.g., Wi-Fi, etc.), or any other type of wireless protocol (e.g., Bluetooth, near field communication (NFC), etc.). In such embodiments, the network-side interface <NUM> comprises one or more antenna/radiating elements. For example, the network-side interface <NUM> may include a single antenna, multiple separate antennas, or a multi-antenna array configured for multi-layer communication, e.g., single input multiple output (SIMO), multiple input single output (MISO), multiple input multiple output (MIMO), etc. In other embodiments, the transceiver <NUM> transmits and receives signaling over a wireline medium, e.g., twisted-pair cable, coaxial cable, optical fiber, etc. Specific processing systems and/or transceivers may utilize all of the components shown, or only a subset of the components, and levels of integration may vary from device to device.

Although several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented.

Claim 1:
A method for wireless communications, the method performed by an apparatus and comprising:
transmitting an orthogonal frequency division multiple access, OFDMA, frame in accordance with a <NUM> tone plan;
wherein the <NUM> tone plan comprises <NUM> guard tones, first two <NUM>-tone resource units, RUs, first <NUM> tones of a bifurcated <NUM>-tone RU, <NUM> DC tones, second <NUM> tones of the bifurcated <NUM>-tone RU, second two <NUM>-tone RUs, and <NUM> guard tones; and
wherein the first two <NUM>-tone RUs are positioned between the <NUM> guard tones and the first <NUM> tones of the bifurcated <NUM>-tone RU, the first <NUM> tones of the bifurcated <NUM>-tone RU are positioned between the first two <NUM>-tone RUs and the <NUM> DC tones, the <NUM> DC tones are positioned between the first <NUM> tones of the bifurcated <NUM>-tone RU and the second <NUM> tones of the bifurcated <NUM>-tone RU, the second <NUM> tones of the bifurcated <NUM>-tone RU are positioned between the <NUM> DC tones and the second two <NUM>-tone RUs, the second two <NUM>-tone RUs are positioned between the second <NUM> tones of the bifurcated <NUM>-tone RU and the <NUM> guard tones.