CN106464638B

CN106464638B - High Efficiency (HE) communication station and method for communicating longer duration OFDM symbols within 40MHz and 80MHz bandwidth allocations

Info

Publication number: CN106464638B
Application number: CN201580025791.6A
Authority: CN
Inventors: S·阿齐兹; T·J·肯尼; E·佩拉亚
Original assignee: Intel IP Corp
Current assignee: SOLID CO.,LTD.
Priority date: 2014-06-18
Filing date: 2015-06-11
Publication date: 2020-01-03
Anticipated expiration: 2035-06-11
Also published as: WO2015195460A1; EP3158702A1; CN106464638A; EP3158702A4

Abstract

Embodiments of a High Efficiency (HE) communication station and method for HE communication in a wireless network are generally described herein. The HE communication station may communicate 4x longer duration OFDM symbols on channel resources in accordance with OFDMA techniques. The channel resources may include one or more resource allocation units, each resource allocation unit having a predetermined number of data subcarriers. The station may also configure the resource allocation unit according to one of a plurality of subcarrier allocations for one of a plurality of interleaver configurations. The station may process the longer-duration OFDM symbols with a 512-point Fast Fourier Transform (FFT) for communications over a 40MHz channel bandwidth that includes a 40MHz resource allocation unit, and may process the longer-duration OFDM symbols with a 1024-point FFT for communications over an 80MHz channel bandwidth that includes two 40MHz resource allocation units or one 80MHz resource allocation unit.

Description

High Efficiency (HE) communication station and method for communicating longer duration OFDM symbols within 40MHz and 80MHz bandwidth allocations

Priority requirement

This application claims the benefit of the following priority: U.S. application serial No.14/447,254 filed on 30/7/2014, U.S. provisional patent application No.62/013,089 filed on 18/6/2014, U.S. provisional patent application No.62/024,801 filed on 15/7/2014, U.S. application serial No. 14/573,912 filed on 17/12/2014, and U.S. provisional patent application No.62/039,320 filed on 19/8/2014; all of which are incorporated herein by reference in their entirety.

Technical Field

Embodiments pertain to wireless networks. Some embodiments relate to Wireless Local Area Networks (WLANs) and Wi-Fi networks, including networks operating according to the IEEE802.11 family of standards. Some embodiments relate to the high efficiency WLAN research group (HEW SG) (named DensiFi) and are referred to as 802.11ax SG. Some embodiments relate to High Efficiency (HE) wireless communications and high efficiency wlan (hew) communications, including HE Wi-Fi communications.

Background

Wireless communications have evolved towards increasing data rates (e.g., from IEEE802.11 a/g to IEEE802.11 n to IEEE802.11 ac). In high density deployment scenarios, overall system efficiency may become more important than higher data rates. For example, in high density hotspot and cellular offload scenarios, many devices competing for the wireless medium may have low to medium data rate requirements (relative to the very high data rates of IEEE802.11 ac). Frame structures for legacy and legacy IEEE802.11 communications, including Very High Throughput (VHT) communications, may not be appropriate for these high-density deployment scenarios. A recently formed task group of high efficiency WLANs called IEEE802.11ax is addressing these high density deployment scenarios.

One issue with HEW is defining a highly efficient communication structure that can reuse at least some of the IEEE802.11 ac hardware (e.g., tone allocation and block interleaver circuitry). Another issue with HEW is defining a highly efficient communication structure suitable for use with longer OFDM symbol durations, particularly OFDM symbols having a duration four times (4x) long or longer than a standard (1x) symbol duration. Another issue with HEW is defining a highly efficient communication structure suitable for use with longer OFDM symbol durations for communicating over wider bandwidths (e.g., 40MHz bandwidth and 80MHz bandwidth).

Accordingly, there is a general need for apparatus and methods that improve overall system efficiency in wireless networks, particularly for high-density deployment scenarios. There is also a general need for apparatus and methods suitable for HEW communication. There is also a general need for apparatus and methods for HEW communications that are suitable for enabling communications according to a highly efficient communication architecture and that can reuse at least some of the legacy hardware. There is also a general need for devices and methods suitable for HEW communication that are capable of communicating according to high-efficiency communication structures that use longer-duration OFDM symbols, including high-efficiency communication structures suitable for use with longer OFDM symbol durations for communicating over wider bandwidths (e.g., 40MHz bandwidths and 80MHz bandwidths).

Drawings

Fig. 1 illustrates a HEW network according to some embodiments;

fig. 2 is a partial physical layer block diagram of an HEW communication station in accordance with some embodiments;

fig. 3 illustrates a HEW device according to some embodiments; and

fig. 4 is a process for communicating using resource allocation units, according to some embodiments.

Detailed Description

The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, process, and other changes. Portions or features of some embodiments may be included in or substituted for those of others. Embodiments set forth in the claims encompass all available equivalents of those claims.

Fig. 1 illustrates a HEW network according to some embodiments. The HEW network 100 may include a master Station (STA)102, a plurality of HEW stations 104(HEW devices), and a plurality of legacy stations 106 (legacy devices). The master station 102 may be arranged to: communicate with HEW stations 104 and legacy stations 106 according to one or more of the IEEE802.11 standards. According to some HEW embodiments, the master station 102 may be arranged to: contending for the wireless medium (e.g., during a contention period) to receive exclusive control of the medium for a HEW control period (i.e., transmission opportunity (TXOP)). The master station 102 may transmit a master synchronization or control transmission, for example, at the beginning of an HEW control period, to indicate which HEW stations 104 are scheduled to communicate during the HEW control period, and so on. During the HEW control period, scheduled HEW stations 104 may communicate with the master station 102 according to a non-contention based multiple access technique. This is different from conventional Wi-Fi communications where devices communicate according to contention-based communication techniques rather than non-contention-based multiple access techniques. During the HEW control period, the master station 102 may communicate with the HEW device 104 (e.g., using one or more HEW frames). During the HEW control period, the legacy stations 106 may refrain from communicating. In some embodiments, the primary synchronization transmission may be referred to as a control and scheduled transmission.

In some embodiments, the multiple access technique used during the HEW control period may be a scheduled Orthogonal Frequency Division Multiple Access (OFDMA) technique, but this is not a requirement. In some embodiments, the multiple access technique may be a Time Division Multiple Access (TDMA) technique or a Frequency Division Multiple Access (FDMA) technique that may be combined with OFDMA. In some embodiments, the multiple access techniques may be Spatial Division Multiple Access (SDMA) techniques, including multi-user (MU) Multiple Input Multiple Output (MIMO) (MU-MIMO) techniques, which may be combined with OFDMA. These multiple access techniques used during the HEW control period may be configured for uplink or downlink data communications. OFDMA enables simultaneous multiplexing of different users for improved efficiency.

The master station 102 may also communicate (outside of the control period) with the legacy stations 106 in accordance with legacy IEEE802.11 communication techniques. In some embodiments, the master station 102 may also be configurable to: communication with HEW stations 104 outside of the control period is in accordance with legacy IEEE802.11 communication techniques, but this is not a requirement.

In some embodiments, HEW communication during the control period may be configurable to: having a bandwidth of one of 20MHz, 40MHz, or 80MHz continuous bandwidth or 80+80MHz (160MHz) discontinuous bandwidth. In some embodiments, a 320MHz channel bandwidth may be used. In some embodiments, a subchannel bandwidth of less than 20MHz may also be used. In these embodiments, each channel or sub-channel of HEW communication may be configured to transmit multiple spatial streams. The HEW communication during the control period may be uplink or downlink communication.

Some embodiments disclosed herein provide systems and methods for subcarrier (e.g., tone) allocation in HEW networks. In some embodiments, master station 102 or HEW station 104 may allocate tones to provide a minimum OFDMA bandwidth unit (i.e., resource allocation unit). In some embodiments, the master station 102 or HEW communication station 104 may be configured to: longer duration Orthogonal Frequency Division Multiplexing (OFDM) symbols are communicated on channel resources including one or more resource allocation units. Each resource allocation unit may have a predetermined bandwidth and the resource allocation units may be configured according to one of a plurality of subcarrier allocations for one of a plurality of interleaver configurations. In some embodiments, an optimized subcarrier allocation and interleaver size combination is provided for use with OFDMA resource allocation units for communications using longer duration OFDM symbols. These embodiments are discussed in more detail below. Some embodiments disclosed herein may be applicable to communications using longer duration OFDM symbols (e.g., having 4x symbol duration or longer), although the scope of the embodiments is not limited in this respect. Some embodiments disclosed herein may be applicable to communications using larger Fast Fourier Transform (FFT) sizes, although the scope of the embodiments is not limited in this respect.

According to an embodiment, an HEW station (e.g., master station 102 or HEW station 104) may be configured to: longer duration OFDM symbols are communicated over channel resources according to OFDMA techniques. The channel resources may include one or more resource allocation units, each of which may have a predetermined number of data subcarriers. Longer duration OFDM symbols may have 4 standard OFDM symbol duration (i.e., symbol time (e.g., T)_symbol) ) symbol duration. The resource allocation unit may be configured according to one of a plurality of subcarrier allocations for one of a plurality of interleaver configurations. These embodiments are discussed in more detail below. Some embodiments disclosed herein may be applicable to IEEE802.11ax and HEW networks operating with longer OFDM symbol durations, such as four times (4x) the standard symbol duration, although the scope of the embodiments is not so limited.

As discussed in more detail below, the HEW master station 102 and the HEW stations 104 may include physical layer (PHY) and medium access control layer (MAC) circuitry. In some embodiments, the PHY circuitry may include a block interleaver having a depth of one OFDM symbol. The block interleaver may be configurable to: the encoded data block is interleaved according to any one of a plurality of interleaver configurations. The interleaver configuration may include a plurality of columns and a plurality of rows. These embodiments are discussed in more detail below.

Fig. 2 is a partial physical layer block diagram of an HEW communication station in accordance with some embodiments. The PHY layer circuitry 200 may be adapted to operate as part of a physical layer of an HEW communication station, such as the master station 102 (fig. 1) and/or the HEW communication station 104 (fig. 1). As shown in fig. 2, the PHY layer circuitry 200 may include, among other things, one or more encoders 208, one or more block interleavers 214, one or more constellation mappers 216, and FFT processing circuitry 218. Each encoder 208 may be configured to: the input data is encoded before being interleaved by interleaver 214. Each constellation mapper 216 may be configured to: the interleaved data is mapped to a constellation (e.g., a Quadrature Amplitude Modulation (QAM) constellation) after interleaving. Each interleaver 214 may be configured to: the encoded data block is interleaved according to any one of a plurality of interleaver configurations. In some embodiments, encoder 208 may be a Binary Convolutional Code (BCC) encoder, although the scope of the embodiments is not limited in this respect. In some embodiments, encoder 208 may be a Low Density Parity Check (LDPC) encoder. FFT processing circuitry 218 may perform an FFT on the constellation mapped symbols provided by the constellation mapper to generate time domain signals for transmission by one or more antennas. In embodiments where BCC encoding is performed, interleaving is performed, whereas in embodiments where LDPC encoding is performed, interleaving is not performed.

According to an embodiment, the encoder 208 and mapper 216 operate according to one of a plurality of predetermined Modulation Coding Scheme (MCS) combinations for a particular subcarrier allocation (i.e., tone allocation). The plurality of predetermined MCS combinations for subcarrier allocation may be limited to an integer number of coded bits per OFDM symbol (Ncbps) and an integer number of data bits per OFDM symbol (Ndbps). In these embodiments, the number of coded bits per OFDM symbol is an integer number and the number of data bits per OFDM symbol is an integer number. The predetermined MCS combination and subcarrier allocation that may be used may include modulation orders of BPSK, QPSK, 16-QAM, 64-QAM, and 256-QAM and coding rates of 1/2, 3/4, 2/3, and 5/6, provided that Ncbps and Ndbps are both integers. The non-integer number Ndbps may result in a non-integer number of padding bits, or the number of coded bits exceeds the number of OFDM symbols, which may result in the OFDM symbols being composed of only padding bits. The integer Ndbps can ensure that all data lengths are feasible without additional padding using IEEE802.11 n "Number of OFDM Symbols" (equation (20-32)) in the IEEE 802.112012 specification. Thus, some embodiments disclosed herein may be limited to certain MCS combinations and subcarrier allocations. In these embodiments, the interleaver hardware architecture configuration is within the boundaries of the IEEE802.11 interleaver, allowing legacy IEEE802.11 hardware blocks to be reused for HEW.

In some of these embodiments, HEW communication station 102/104 may be configured to encode input data based on a coding rate prior to interleaving, and may be configured to map interleaved bit constellations to QAM constellation points based on a modulation level after interleaving. The code rate and modulation level may be in accordance with one of the predetermined MCS combinations for the particular subcarrier allocation. These embodiments are described in more detail below.

In some embodiments, each resource allocation unit may be configurable for communication between one spatial stream and four spatial streams, although the scope of the embodiments is not limited in this respect. In these embodiments, spatial streams may be communicated using SDMA or MIMO techniques during the control period. In some embodiments, each resource allocation unit may be configurable for communication of up to eight or more spatial streams.

Some embodiments disclosed herein provide for the number of data subcarriers, the number of pilot subcarriers, and the size of the block interleaver for the case of binary convolutional code encoding. In some embodiments, the structure of the OFDMA waveform for IEEE802.11ax described in U.S. provisional patent application serial No.61/976,951 may be suitable for use, but this is not a requirement. Some embodiments disclosed herein describe resource allocation units for OFDMA waveforms and describe subcarrier allocation. In some embodiments, the subcarrier allocation may be configured to: some IEEE802.11 ac hardware is reused to create a new OFDMA structure.

According to some embodiments, an HEW communication station (e.g., the master station 102 or the HEW station 104) may be configured to: longer duration OFDM symbols are communicated over channel resources according to OFDMA techniques. The channel resources may include one or more resource allocation units, each of which may include a predetermined number of data subcarriers. In some embodiments, the HEW communication station may configure the resource allocation unit according to one of a plurality of subcarrier allocations for one of a plurality of interleaver configurations for communication of the longer duration OFDM symbols. In these embodiments, the longer duration OFDM symbol may have a symbol duration four times as long (4x) as the standard OFDM symbol duration, and the station may be configurable to: the longer-duration OFDM symbols are processed with at least one of a 512-point Fast Fourier Transform (FFT) (for communications over a 40MHz channel bandwidth that includes a 40MHz resource allocation unit) and a 1024-point FFT (for communications over an 80MHz channel bandwidth). The 80MHz channel bandwidth may include two 40MHz resource allocation units or one 80MHz resource allocation unit. These embodiments are discussed in more detail below. The FFT processing circuit 218 may be configured to perform 512-point FFT, 1024-point FFT, and the like.

In some embodiments, when operating as the master station 102, the communication station may be configurable to: a 512-point FFT is used to process longer-duration OFDM symbols for a single subscriber station (e.g., HEW station 104) for communications within a 40MHz resource allocation unit, a 1024-point FFT is used to process longer-duration OFDM symbols for a single subscriber station for communications within an 80MHz resource allocation unit, and a 512-point FFT is used to process longer-duration OFDM symbols for two subscriber stations for communications within an 80MHz resource allocation unit. In these embodiments, the subscriber station may operate using an 80MHz bandwidth in a Basic Service Set (BSS) and may process 4x symbols using a 1024-point FFT. The subscriber station may also operate using the 40MHz bandwidth in the BSS and may process 4x symbols using a 512 point FFT. Although embodiments are described herein with respect to 4x symbol duration, in some alternative embodiments, a 512-point FFT may be used to process symbols having a 2x symbol duration within an 80MHz resource allocation unit, and a 1024-point FFT may be used to process symbols having an 8x symbol duration within a 40MHz resource allocation unit.

In some embodiments, to process longer-duration OFDM symbols with a 1024-point FFT without excluding code rate 5/6 for 256-QAM, the predetermined number of data subcarriers for an 80MHz resource allocation unit may include 936 data subcarriers for an interleaver configuration with 26 columns, 960 data subcarriers for an interleaver configuration with 15 or 20 columns, 984 data subcarriers for an interleaver configuration with 24 or 41 columns, and 990 data subcarriers for an interleaver configuration with 22, 30, or 33 columns, although the scope of the embodiments is not limited in this respect. These and other embodiments are described in more detail below and shown in table III below.

In some embodiments, to process longer duration OFDM symbols with a 512-point FFT without excluding a code rate 5/6 for 256-QAM, the predetermined number of data subcarriers for a 40MHz resource allocation unit may include 468 data subcarriers for an interleaver configuration having 26 columns and 486 data subcarriers for an interleaver configuration having 18 or 27 columns. In these embodiments, to process longer duration OFDM symbols with a 512-point FFT excluding code rate 5/6 for 256-QAM, the predetermined number of data subcarriers for a 40MHz resource allocation unit may include 490 data subcarriers for an interleaver configuration having 14 or 35 columns. These and other embodiments are described in more detail below and shown in table VI below.

In some embodiments, the HEW master station 102 may be configurable to: longer-duration OFDM symbols received within a 40MHz resource allocation unit from one or two subscriber stations are processed using a 512-point FFT and longer-duration OFDM symbols received within a 20MHz resource allocation unit from one subscriber station are processed using a 256-point FFT. In some of these embodiments, to process longer duration OFDM symbols with a 256-point FFT without code rate exclusion, the predetermined number of data subcarriers for the 20MHz resource allocation unit may include 234 data subcarriers for an interleaver configuration having 26 columns, 228 data subcarriers for an interleaver configuration having 19 columns, and 240 data subcarriers for an interleaver configuration having 20 columns. These and other embodiments are described in more detail below and shown in table VIII below.

In some embodiments, the HEW master station 102 may also be configurable to: a 256-point FFT is used to process longer duration OFDM symbols received in a 20MHz resource allocation unit from two subscriber stations. To process longer duration OFDM symbols from two subscriber stations without precluding a code rate 5/6 for 256-QAM, the predetermined number of data subcarriers for a 20MHz resource allocation unit may include 102 data subcarriers for an interleaver configuration having 6 or 17 columns and 108 data subcarriers for an interleaver configuration having 18 columns. These and other embodiments are described in more detail below and shown in table X below. To process longer duration OFDM symbols from two subscriber stations, excluding the code rate 5/6 for 256-QAM, the predetermined number of data subcarriers for a 20MHz resource allocation unit may be 104 data subcarriers for an interleaver configuration having 13 columns. These and other embodiments are described in more detail below and shown in table IX below.

In some embodiments, interleaver 214 (fig. 2) may be a block interleaver having a depth of one OFDM symbol and may be configurable to interleave a coded data block. The interleaver configuration may include a plurality of columns and a plurality of rows, wherein the number of rows may be based on the number of coded bits per subcarrier per stream. In some embodiments, encoder 208 may encode the input data prior to interleaving according to one of a plurality of code rates. The constellation mapper 216 may map the interleaved encoded data to a QAM constellation. In some embodiments, the encoder 208 and mapper 216 may operate according to one of a plurality of predetermined Modulation Coding Scheme (MCS) combinations for subcarrier allocation. The plurality of predetermined MCS combinations for subcarrier allocation may be limited to an integer number of coded bits per OFDM symbol (Ncbps) and an integer number of data bits per OFDM symbol (Ndbps).

In some embodiments, longer duration OFDM symbols may be selected for larger delay spread environments and standard duration OFDM symbols may be selected for smaller delay spread environments. Standard duration OFDM symbols may be used for legacy communications (e.g., IEEE802.11 a/n/ac/g), and the symbol duration is not based on the delay spread of the channel. In some embodiments, a standard-duration OFDM symbol may have a symbol duration ranging from 3.6 microseconds (μ s), including a 400 nanosecond (ns) short guard interval, to 4 μ s, including an 800ns guard interval. In some embodiments, the symbol duration of the longer-duration OFDM symbol is the duration of a 4x standard-duration OFDM symbol. In these embodiments, when a 4x longer symbol duration is used in a 40 or 80MHz resource allocation unit, for example, the subcarrier spacing may be reduced to one-fourth (e.g., one-fourth of 312.5 KHz). In these embodiments, for closer subcarrier spacing, subcarrier assignments with more guard subcarriers may be used. In some embodiments, the master station 102 may be configured to: communication is performed simultaneously using several resource allocation units within the channel bandwidth.

In these embodiments, a detailed design for 1024-point FFT and 512-point FFT in IEEE802.11ax 80MHz and 40MHz operating bandwidths is provided (e.g., the number of data subcarriers and the number of pilot subcarriers, and for the case of BCC coding, it provides the size of the block interleaver). 1024-point FFTs as well as 512-point FFTs can be used with 4x symbol duration, and in particular, are of interest in both outdoor and indoor environments. In an outdoor environment, fourfold longer symbol duration may enable the use of a more efficient Cyclic Prefix (CP) to overcome the longer delay spread. In an indoor environment, longer symbol durations may allow for more relaxed requirements on clock timing accuracy.

In order to determine a better configuration for data/pilot tone count and interleaver size based on channel model, MCS and other parameters, a system simulation is performed. Since the embodiments disclosed herein define tone counts, the search is exhaustive within the boundaries to achieve some reasonable tone/pilot counts and subcarrier allocations.

The contribution to IEEE802.11ax SIG has proposed many configurations for the number of data/pilot tone allocations, but none of these proposals are based on exhaustive search within the boundaries to reach a reasonable subcarrier allocation that also defines the size of the block interleaver for BCC coding. As described above, new use cases introduced in HEWs targeting high-density deployment scenarios, including better control over the larger bandwidth to be scheduled by the HEW master station 102 or HEW Access Points (APs), improve current Wi-Fi systems and thereby help meet task group objectives.

Some possible assignments to each group (data, pilot, and block interleaver size) are outlined below, and some subcarrier assignments that may be more beneficial are identified. In an OFDMA system, the total number of subcarriers used in the minimum bandwidth unit may be a system design parameter. From the total subcarrier count, the OFDMA system has subcarriers allocated to data (for data), pilot (typically for time/frequency and channel tracking), guard (for conforming to spectral masking), and subcarriers at and around DC (to simplify direct conversion receiver design). For example, in 20MHz IEEE802.11 ac, the fixed subcarrier spacing is 312.5kHz, and therefore, the total number of subcarriers is 64. Of these 64 subcarriers, 52 subcarriers are designated for data, 1 subcarrier for DC (assuming null), 4 subcarriers for pilot, and the remaining 7 subcarriers for guard (assuming null).

Embodiments disclosed herein provide subcarrier allocation based on a set of modulation types (e.g., BPSK, QPSK, 16-QAM, 64-QAM, and 256-QAM) used in previous systems. The code rates utilized in previous systems include the following set r ═ 1/2, 3/4, 2/3, and 5/6. Not all code rates of the set are necessarily used for all modulation types, but it does include all current rates used over the entire modulation set. To determine the effective subcarrier allocation, the same modulation coding allocation as in the previous system (e.g., IEEE802.11 a/.11n/.11ac system) may be used.

In some embodiments, the existing channel interleaver of the previous IEEE802.11 OFDM system may be used. The following channel interleavers may be used, for example, IEEE Std.802.11ac-2013 "IEEE Standard for information technologies and information exchange between systems-Localand metric areas networks-Part 11: wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications, interpretation 4: the channel interleaver defined in section 22.3.10.8 of Enhancements for VeryHigh through for Operation in Bands below 6GHz ", although the scope of the embodiments is not limited in this respect. The interleaver parameters are summarized in the IEEE Specification of Number of Rows and columns inter interleaver of tables 22-17. For the case of 1 to 4 spatial streams, the table is included herein in its entirety as table I.

TABLE I

Number of rows and columns in an interleaver

In IEEE802.11 n, the introduction of 40MHz is done by reusing the existing interleaver algorithm by modifying the matrix size defined to write and read data. Next, in IEEE802.11 ac, the same interleaver algorithm is utilized with the introduction of 80 MHz. These parameters define the number of code symbols stored in the interleaver. Embodiments disclosed herein may also define new values for NCOL and NROW for OFDMA allocation, reusing existing interleaver algorithms. Since the NROT operation defines a rotation of the value when more than one spatial stream is present, this term can be ignored, since NROT does not define the interleaver size and will therefore not affect the subcarrier selection.

As can be seen in the above table, NROW is a constant multiple of the number of coded bits per subcarrier per stream. Thus, the interleaver physical size is a function of the MCS. Some embodiments disclosed herein define a constant (y) used in calculating NROW. Embodiments disclosed herein define subcarrier allocations based on an exhaustive search within boundaries to arrive at all reasonable subcarrier allocations under the target constraints outlined above. Some embodiments disclosed herein may not provide an accurate definition of interleaver parameters, but rather provide a solution for many interleaver structures that uses the above constraints. Embodiments disclosed herein provide subcarrier allocation sets using the above constraints that are suitable for use with the longer symbol durations of OFDMA 80MHz and 40MHz bandwidth units, and may allow up to 18 users to be multiplexed in 80MHz (or up to 9 users to be multiplexed in 40 MHz).

As described above, in 20MHz IEEE802.11 ac, the fixed subcarrier spacing is 312.5kHz, and therefore, the total number of subcarriers is 64. Of these 64, 52 are used for data, 1 for DC (assumed null), 4 for pilot, and the remaining 7 for protection (assumed null). According to some embodiments for a 4x symbol duration, the FFT size may be 256 in 20MHz, 512 in 40MHz, 1024 in 80 MHz. Initially, an algorithm may be used to search anywhere from 208 to 244 subcarriers for each of the two users with respect to the data subcarriers, which would then allow allocation of 52 to 12 null subcarriers in a 40MHz bandwidth for 2 users, respectively. The algorithm can then search anywhere from 416 to 504 sub-carriers for each of the two users with respect to the data sub-carriers, which would then allow 96 to 8 null sub-carriers to be allocated in the 80MHz bandwidth for 2 users, respectively. To determine whether a configuration is possible, a set of formulas may be used. Finally, the algorithm can search anywhere from 896 to 1012 subcarriers for one user with respect to the data subcarriers, which would then allow allocation of 128 to 12 null subcarriers in the 80MHz bandwidth, respectively. For clarity, a set of variables is defined as follows:

with these definitions, the set of procedures and formulas for determining whether a configuration is valid are summarized as follows:

1. selecting the number of data subcarriers (N)_SD) Carry out the test

2. Calculating N_CBPS＝N_SD*M

3. Calculating N_BPSCS＝N_CBPS*N_SD

4. Calculating N_ROW＝y*N_BPSCS(ii) a (where y is the assigned interleaver parameter)

5. Calculating INT_DIM＝N_ROM*N_COL

6. Computing

7. Computing

8. Computing

9. Test if ((M)₁＝0)&(M₂0)), then valid, otherwise invalid

Thus, if M₁&M₂A configuration using the code rate and modulation is allowable, otherwise disabled.

The script may be configured to find possible combinations. In the first round, all modulations can be supported with respect to 40MHz and 80MHz assumptions, as in IEEE802.11 ac. Including 64-QAM (introduced in IEEE802.11 ac) and 256-QAM with code rates 3/4 and 5/6. For this assumption, allowing allocation for 1024-point FFT may include:

TABLE II

The search results indicate that there are many possibilities for the number of data tones that will leave an extra subcarrier within 80 MHz. The extra tones may be used for pilot tones, nulls at DC, null subcarriers as guard bands, and even null subcarriers to be inserted between users. Preferred choices are summarized in the following table according to the above list.

TABLE III

Table IIIa (below) lists some additional allocation sizes including 256-QAM with code rate 5/6 in addition to those already listed in table III.

Watch (IIIa)

A similar search may be performed for two users in 80MHz (with 1024 point FFT) or for one user in 40MHz (with 512 point FFT) to provide the following allowable allocations:

TABLE IV

The search may be repeated but without supporting code rate 5/6 at 256QAM (i.e., the same exclusion case for 20MHz in IEEE802.11 ac). In this case, possible assignments for the 512-point FFT may include, in addition to those listed in table IV:

TABLE V

The search results indicate that there are many possibilities for the number of data tones that will leave additional subcarriers within 80MHz and/or 40 MHz. These extra tones may be used for pilot tones, nulls at DC, null subcarriers as guard bands, and even null subcarriers to be inserted between users. From the above list, the preferred choices are outlined below.

TABLE VI

The search may be repeated for two users in 40MHz (with 512 point FFT) or for one user in 20MHz (with 256 point FFT) and the allowed allocations may include:

TABLE VII

From the above list, the preferred choices are outlined below.

TABLE VIII

The search may be repeated for two users in 20MHz (256 point FFT) where the code rate 5/6 at 256QAM needs to be supported (the first three columns of table IX) and where the code rate 5/6 at 256QAM does not need to be supported (the last three columns of table IX), the latter being the same exclusion case for 20MHz in 802.11 ac. In this case, options for a 512-point FFT may include:

TABLE IX

From the above list, preferred choices are shown in the following table.

Table X

In the case of Low Density Parity Check (LDPC) coding, there may be no requirement for interleaver block size, but the above allocations may be used because they are consistent with the allocation size in the case of BCC coding. For the OFDMA mode of ieee802.11ax, these solutions are provided for 1024-point FFT in 80MHz, 512-point FFT in 40MHz and 256-point FFT in 20 MHz.

Fig. 3 illustrates a HEW device according to some embodiments. HEW device 300 may be a HEW compliant device that may be arranged to communicate with one or more other HEW devices (e.g., HEW stations and/or master stations) and communicate with legacy devices. HEW device 300 may be adapted to operate as a master station (HEW master station 102 (fig. 1)) or HEW device 104 (fig. 1). According to an embodiment, HEW device 300 may include physical layer (PHY) circuitry 302 and medium access control layer (MAC) circuitry 304, among other things. The PHY 302 and MAC 304 may be HEW compliant layers and may also be compliant with one or more legacy IEEE802.11 standards. PHY 302 may be arranged to transmit HEW frames. HEW device 300 may also include other processing circuitry 306 and memory 308 configured to perform various operations described herein.

According to some embodiments, the MAC 304 may be arranged to: contend for the wireless medium during a contention period to receive control of the medium for an HEW control period, and configure an HEW frame. PHY 302 may be arranged to transmit HEW frames as described above. PHY 302 may also be arranged to receive HEW frames from HEW stations. The MAC 304 may also be arranged to perform transmit and receive operations through the PHY 302. PHY 302 may include circuitry for modulation/demodulation, up-conversion and/or down-conversion, filtering, amplification, and so forth. In some embodiments, processing circuitry 306 may include one or more processors. In some embodiments, two or more antennas may be coupled to physical layer circuitry arranged to transmit and receive signals (including transmission of HEW frames). The memory 308 may store information for configuring the processing circuitry 306 to perform operations for configuring and transmitting HEW frames and performing various operations described herein.

In some embodiments, HEW device 300 may be configured to: the communication is performed using OFDM communication signals over a multicarrier communication channel. In some embodiments, HEW device 300 may be configured to: signals may be received in accordance with particular communication standards, such as the Institute of Electrical and Electronics Engineers (IEEE) standards including the IEEE 802.11-2012, IEEE802.11 n-2009, IEEE802.11 ac-2013, and/or the IEEE802.11ax standards and/or proposed specifications for WLANs including the proposed HEW standard, although the scope of the invention is not limited in this respect as they may also be suitable for transmitting and/or receiving communications in accordance with other techniques and standards. In some other embodiments, HEW device 300 may be configured to: signals transmitted using one or more other modulation techniques, such as spread spectrum modulation (e.g., direct sequence code division multiple access (DS-CDMA)) and/or frequency hopping code division multiple access (FH-CDMA), Time Division Multiplexing (TDM) modulation, and/or Frequency Division Multiplexing (FDM) modulation, are received, although the scope of the embodiments is not limited in this respect.

In some embodiments, HEW device 300 may be part of: in some embodiments, the HEW device 300 can include one or more of a keyboard, a display, a non-volatile memory port, a plurality of antennas, a graphics processor, an application processor, a speaker, and other mobile device elements.

The antenna 301 of the HEW device 300 may include one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some multiple-input multiple-output (MIMO) embodiments, antennas 301 may be effectively separated to take advantage of spatial diversity and the different channel characteristics that may result between each antenna and the antennas of the transmitting station.

Although HEW device 300 is illustrated as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements (e.g., processing elements including digital signal processors) and/or other hardware elements. For example, some elements may comprise one or more microprocessors, DSPs, Field Programmable Gate Arrays (FPGAs), Application Specific Integrated Circuits (ASICs), Radio Frequency Integrated Circuits (RFICs), and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements of HEW device 300 may refer to one or more processes operating on one or more processing elements.

Embodiments may be implemented in one or a combination of hardware, firmware, and software. Embodiments may also be implemented as instructions stored on a computer-readable storage device, which may be read and executed by at least one processor to perform the operations described herein. A computer-readable storage device may include any non-transitory mechanism (e.g., a computer) for storing information in a form readable by a machine. For example, a computer-readable storage device may include Read Only Memory (ROM), Random Access Memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, and other storage devices and media. Some embodiments may include one or more processors and may be configured with instructions stored on a computer-readable storage device.

Fig. 4 is a process for communicating longer duration OFDM symbols using resource allocation units, in accordance with some embodiments. Process 400 may be performed by a HEW device, such as HEW station 104 (fig. 1) or HEW master 102 (fig. 1).

Operation 402 comprises: the block interleaver is configured to: the encoded input data block is interleaved according to one of a plurality of interleaver configurations determined for the subcarrier allocation of the resource allocation unit for the longer duration OFDM symbol.

Operation 404 comprises: the longer duration OFDM symbols are processed with a 512-point FFT for communication over a 40MHz channel bandwidth that includes a 40MHz resource allocation unit.

Operation 406 comprises: the longer duration OFDM symbols are processed with a 1024-point FFT for communication over an 80MHz channel bandwidth that includes two 40MHz resource allocation units or one 80MHz resource allocation unit. The HEW device may be configured to: depending on the resource allocation unit size, either operation 404 or operation 406 is performed.

Operation 408 comprises: longer-duration OFDM symbols are communicated over channel resources (in the form of time-domain OFDMA waveforms) that include one or more resource allocation units in accordance with a non-contention-based communication technique. In some embodiments, longer duration OFDM symbols may be communicated during a control period (e.g., TXOP) in accordance with MU-MIMO techniques.

In an example, a High Efficiency (HE) communication Station (STA) includes physical layer and medium access control layer circuitry to: communicating longer-duration Orthogonal Frequency Division Multiplexing (OFDM) symbols on channel resources according to an Orthogonal Frequency Division Multiple Access (OFDMA) technique, the channel resources including one or more resource allocation units, each resource allocation unit including a predetermined number of data subcarriers; configuring the resource allocation unit according to one of a plurality of subcarrier allocations for communicating longer duration OFDM symbols; and processing the longer duration OFDM symbol with at least one of: for communications over a 40MHz channel bandwidth including a 40MHz resource allocation unit, a 512 point Fast Fourier Transform (FFT) is used; and using a 1024 point FFT for communications over an 80MHz channel bandwidth that includes two 40MHz resource allocation units or one 80MHz resource allocation unit.

In another example, for Binary Convolutional Code (BCC) coding, the resource allocation unit is further configured according to one of a plurality of interleaver configurations for subcarrier allocation for communicating longer duration OFDM symbols having a symbol duration that is four times as long (4x) as a standard OFDM symbol duration, and when operating as the master station 102, the communication station is configured to: for communications within a 40MHz resource allocation unit, a 512-point FFT is used to process longer duration OFDM symbols for a single subscriber station; for communications within an 80MHz resource allocation unit, processing longer duration OFDM symbols for a single subscriber station using a 1024-point FFT; and for communications within the 80MHz resource allocation unit, processing the longer duration OFDM symbols for both subscriber stations using a 512 point FFT.

In another example, for processing longer-duration OFDM symbols with a 1024-point FFT without excluding the code rate 5/6 of 256-QAM, the predetermined number of data subcarriers used for 80MHz resource allocation units is one of: for an interleaver configuration with 26 columns, for 936 data subcarriers, for an interleaver configuration with 15 or 20 columns, for 960 data subcarriers, for an interleaver configuration with 24 or 41 columns, for 984 data subcarriers, and for an interleaver configuration with 22, 30 or 33 columns, for 990 data subcarriers, and for Low Density Parity Check (LDPC) coding the predetermined number of data subcarriers for an 80MHz resource allocation unit is one of 936 data subcarriers, 960 data subcarriers, 984 data subcarriers, and 990 data subcarriers.

In another example, for processing longer-duration OFDM symbols with a 512-point FFT without excluding a code rate 5/6 of 256-QAM, the predetermined number of data subcarriers used for the 40MHz resource allocation unit is one of: 468 data subcarriers for an interleaver configuration with 26 columns and 486 data subcarriers for an interleaver configuration with 18 or 27 columns. For processing longer duration OFDM symbols with a 512-point FFT excluding a code rate of 5/6 of 256-QAM, the predetermined number of data subcarriers for a 40MHz resource allocation unit encoded for BCC is one of 468, 486 and 490 data subcarriers configured for an interleaver with 14 or 35 columns to 490 data subcarriers and for Low Density Parity Check (LDPC) encoding to the data subcarriers for the 40MHz resource allocation unit.

In another example, the station is further configured to: processing longer duration OFDM symbols received within a 40MHz resource allocation unit from one or two subscriber stations using a 512 point FFT; and processing longer duration OFDM symbols received within the 20MHz resource allocation unit from one subscriber station using a 256-point FFT.

In another example, for processing longer-duration OFDM symbols with a 256-point FFT without code rate exclusion, the predetermined number of data subcarriers for the 20MHz resource allocation unit is one of: 234 data subcarriers are configured for an interleaver having 26 columns, 228 data subcarriers are configured for an interleaver having 19 columns, and 240 data subcarriers are configured for an interleaver having 20 columns, and the predetermined number of data subcarriers for a 20MHz resource allocation unit for Low Density Parity Check (LDPC) encoding is one of 234, 228, and 240 data subcarriers.

In another example, the station is further configured to: processing longer duration OFDM symbols received within a 20MHz resource allocation unit from two subscriber stations using a 256 point FFT; and for processing longer duration OFDM symbols from two subscriber stations without excluding a code rate 5/6 of 256-QAM, the predetermined number of data subcarriers used for the 20MHz resource allocation units is one of: 102 data subcarriers are configured for an interleaver having 6 or 17 columns and 108 data subcarriers are configured for an interleaver having 18 columns. For processing longer duration OFDM symbols from two subscriber stations with the exception of a code rate 5/6 of 256-QAM, the predetermined number of data subcarriers for BCC encoding for a 20MHz resource allocation unit is one of 102, 108 and 104 data subcarriers configured as 104 data subcarriers for an interleaver having 13 columns and for Low Density Parity Check (LDPC) encoding for a 20MHz resource allocation unit.

In another example, the physical layer circuitry includes a block interleaver having a depth of one OFDM symbol, the block interleaver configurable to: the encoded data blocks are interleaved when BCC encoding is used and interleaving is suppressed when Low Density Parity Check (LDPC) is used, and the interleaver configuration comprises a number of columns and a number of rows, the number of rows being based on the number of coded bits per subcarrier per stream.

In another example, the communication station further comprises: an encoder for encoding input data prior to interleaving according to one of a plurality of code rates; and a constellation mapper for mapping the interleaved encoded data to a QAM constellation. The encoder and mapper operate according to one of a plurality of predetermined Modulation Coding Scheme (MCS) combinations for subcarrier allocation, and the plurality of predetermined MCS combinations for subcarrier allocation are limited to an integer number of coded bits per OFDM symbol (Ncbps) and an integer number of data bits per OFDM symbol (Ndbps).

In another example, a longer duration OFDM symbol will be selected for a larger delay spread environment and a standard duration OFDM symbol will be selected for legacy communications or a smaller delay spread environment.

In another example, the standard-duration OFDM symbol has a symbol duration ranging from 3.6 microseconds (μ s) containing a 400 nanosecond (ns) short guard interval to 4 μ s containing an 800ns guard interval.

In another example, the communication station further includes one or more processors and memory, and the physical layer circuitry includes a transceiver. In another example, the communication station further includes one or more antennas coupled to the transceiver.

In another example, a method for High Efficiency (HE) wireless communication, comprising: communicating longer-duration Orthogonal Frequency Division Multiplexing (OFDM) symbols on channel resources according to an Orthogonal Frequency Division Multiple Access (OFDMA) technique, the channel resources including one or more resource allocation units, each resource allocation unit including a predetermined number of data subcarriers; configuring the resource allocation unit according to one of a plurality of subcarrier allocations for communicating longer duration OFDM symbols; and processing the longer duration OFDM symbol with at least one of: for communications over a 40MHz channel bandwidth including a 40MHz resource allocation unit, a 512 point Fast Fourier Transform (FFT) is used; and using a 1024 point FFT for communications over an 80MHz channel bandwidth that includes two 40MHz resource allocation units or one 80MHz resource allocation unit.

In another example, for Binary Convolutional Code (BCC) encoding, the resource allocation unit is further configured according to one of a plurality of interleaver configurations for subcarrier allocation for communication conveying longer duration OFDM symbols, and the symbol duration of the longer duration OFDM symbols is four times as long (4x) as the standard OFDM symbol duration. In this example, the method further comprises: for communications within a 40MHz resource allocation unit, a 512-point FFT is used to process longer duration OFDM symbols for a single subscriber station; for communications within an 80MHz resource allocation unit, processing longer duration OFDM symbols for a single subscriber station using a 1024-point FFT; and for communications within the 80MHz resource allocation unit, processing the longer duration OFDM symbols for both subscriber stations using a 512 point FFT.

In another example, the method further comprises: processing longer duration OFDM symbols received within a 40MHz resource allocation unit from one or two subscriber stations using a 512 point FFT; and processing longer duration OFDM symbols received within the 20MHz resource allocation unit from one subscriber station using a 256-point FFT.

In another example, the method further comprises: during the control period, a longer duration OFDM symbol including one or more resource allocation units is communicated in accordance with a non-contention based communication technique.

In another example, a non-transitory computer-readable storage medium stores instructions for execution by one or more processors to perform operations that configure a High Efficiency (HE) communication Station (STA) to: communicating longer-duration Orthogonal Frequency Division Multiplexing (OFDM) symbols on channel resources according to an Orthogonal Frequency Division Multiple Access (OFDMA) technique, the channel resources including one or more resource allocation units, each resource allocation unit including a predetermined number of data subcarriers; configuring the resource allocation unit according to one of a plurality of subcarrier allocations for communicating longer duration OFDM symbols; and processing the longer duration OFDM symbol with at least one of: for communications over a 40MHz channel bandwidth including a 40MHz resource allocation unit, a 512 point Fast Fourier Transform (FFT) is used; and using a 1024 point FFT for communications over an 80MHz channel bandwidth that includes two 40MHz resource allocation units or one 80MHz resource allocation unit.

In another example, for Binary Convolutional Code (BCC) encoding, the resource allocation unit is further configured according to one of a plurality of interleaver configurations for subcarrier allocation for communicating longer-duration OFDM symbols having a symbol duration that is four times as long (4x) as a standard OFDM symbol duration, and the operations configure the HEW communication station to: for communications within a 40MHz resource allocation unit, a 512-point FFT is used to process longer duration OFDM symbols for a single subscriber station; for communications within an 80MHz resource allocation unit, processing longer duration OFDM symbols for a single subscriber station using a 1024-point FFT; and for communications within the 80MHz resource allocation unit, processing the longer duration OFDM symbols for both subscriber stations using a 512 point FFT.

In another example, the symbol duration of the longer-duration OFDM symbol is four times as long (4x) as a standard OFDM symbol duration, and the operations further configure the HEW communication station to: during the control period, a longer duration OFDM symbol including one or more resource allocation units is communicated in accordance with a non-contention based communication technique.

The abstract is provided to comply with 37 c.f.r section 1.72(b), which requires an abstract that will allow the reader to ascertain the nature and substance of the technical disclosure. It is submitted with the understanding that it will not be used to limit or interpret the scope or meaning of the claims. The following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment.

Claims

1. A high efficiency HE communication station, STA, comprising physical layer and medium access control layer circuitry to:

communicating longer duration orthogonal frequency division multiplexing, OFDM, symbols on channel resources according to an orthogonal frequency division multiple access, OFDMA, technique, the channel resources comprising one or more resource allocation units, each resource allocation unit comprising a predetermined number of data subcarriers;

configuring the resource allocation unit according to one of a plurality of subcarrier allocations for communicating longer duration OFDM symbols; and

processing the longer duration OFDM symbol with at least one of:

for communications over a 40MHz channel bandwidth including a 40MHz resource allocation unit, a 512 point fast fourier transform FFT is used; and

for communication over an 80MHz channel bandwidth that includes two 40MHz resource allocation units or one 80MHz resource allocation unit, a 1024 point FFT is used,

wherein for binary convolutional code BCC coding, the resource allocation unit is further configured according to one of a plurality of interleaver configurations for subcarrier allocation for conveying the longer-duration OFDM symbols,

wherein the longer-duration OFDM symbol has a symbol duration four times as long as a standard OFDM symbol duration, the standard-duration OFDM symbol having a symbol duration ranging from 3.6 microseconds, including a 400 nanosecond short guard interval, to 4 microseconds, including an 800 nanosecond guard interval, and

wherein, when operating as a master station, the communication station is configurable to:

for communications within a 40MHz resource allocation unit, a 512-point FFT is used to process longer duration OFDM symbols for a single subscriber station;

for communications within an 80MHz resource allocation unit, processing longer duration OFDM symbols for a single subscriber station using a 1024-point FFT; and

for communications within an 80MHz resource allocation unit, a 512-point FFT is used to process the longer duration OFDM symbols for both subscriber stations.

2. The communication station of claim 1, wherein for processing longer-duration OFDM symbols with a 1024-point FFT without excluding a code rate 5/6 of 256-QAM, the predetermined number of data subcarriers for the 80MHz resource allocation unit is one of:

for an interleaver configuration with 26 columns, for 936 data subcarriers,

for an interleaver configuration with 15 or 20 columns, for 960 data subcarriers,

for an interleaver configuration with 24 or 41 columns, 984 data subcarriers, and

for an interleaver configuration with 22, 30 or 33 columns, there are 990 data subcarriers, and

the predetermined number of data subcarriers for the 80MHz resource allocation unit for the low density parity check LDPC encoding is one of 936 data subcarriers, 960 data subcarriers, 984 data subcarriers, and 990 data subcarriers.

3. The communication station of claim 1, wherein for processing longer-duration OFDM symbols with a 512-point FFT without excluding a code rate 5/6 of 256-QAM, the predetermined number of data subcarriers for the 40MHz resource allocation unit is one of:

for an interleaver configuration with 26 columns, 468 data subcarriers, and

for an interleaver configuration having 18 or 27 columns, for 486 data subcarriers,

wherein for processing longer duration OFDM symbols with a 512-point FFT with the exception of a code rate 5/6 of 256-QAM, the predetermined number of data subcarriers for BCC encoding for a 40MHz resource allocation unit is 490 data subcarriers configured for an interleaver having 14 or 35 columns, and

the predetermined number of data subcarriers for the 40MHz resource allocation unit for the low density parity check LDPC encoding is one of 468, 486 and 490 data subcarriers.

4. The communication station of claim 1, wherein the communication station is further configurable to:

processing longer duration OFDM symbols received within a 40MHz resource allocation unit from one or two subscriber stations using a 512 point FFT; and

a 256-point FFT is used to process longer duration OFDM symbols received in a 20MHz resource allocation unit from one subscriber station.

5. The communication station of claim 4, wherein for processing longer-duration OFDM symbols with a 256-point FFT without code rate exclusion, the predetermined number of data subcarriers for the 20MHz resource allocation unit are one of:

for an interleaver configuration with 26 columns, for 234 data subcarriers,

for an interleaver configuration with 19 columns, 228 data subcarriers, and

for an interleaver configuration with 20 columns, 240 data subcarriers, and

the predetermined number of data subcarriers for the 20MHz resource allocation unit for the low density parity check LDPC encoding is one of 234, 228 and 240 data subcarriers.

6. The communication station of claim 4, wherein the communication station is further configurable to:

processing longer duration OFDM symbols received within a 20MHz resource allocation unit from two subscriber stations using a 256 point FFT; and is

Wherein for processing longer duration OFDM symbols from two subscriber stations without excluding a code rate 5/6 of 256-QAM, the predetermined number of data subcarriers used for the 20MHz resource allocation units are one of:

for an interleaver configuration with 6 or 17 columns, 102 data subcarriers, and

for an interleaver configuration with 18 columns, for 108 data subcarriers,

wherein for processing longer duration OFDM symbols from two subscriber stations with the exception of a code rate 5/6 of 256-QAM, the predetermined number of data subcarriers for BCC encoding for a 20MHz resource allocation unit is 104 data subcarriers configured for an interleaver having 13 columns, and

the predetermined number of data subcarriers for the 20MHz resource allocation unit for the low density parity check LDPC encoding is one of 102, 108 and 104 data subcarriers.

7. The communication station of claim 1, wherein the physical layer circuitry comprises a block interleaver having a depth of one OFDM symbol, the block interleaver being configurable to: interleaving the encoded data blocks when using BCC coding and suppressing the interleaving when using low density parity check LDPC, and

wherein the interleaver configuration comprises a plurality of columns and a plurality of rows, the number of rows being based on the number of coded bits per subcarrier per stream.

8. The communication station of claim 7, wherein the communication station further comprises:

an encoder for encoding input data prior to interleaving according to one of a plurality of code rates; and

a constellation mapper for mapping the interleaved encoded data to QAM constellations,

wherein the encoder and mapper operate according to one of a plurality of predetermined modulation coding scheme, MCS, combinations for subcarrier allocation,

wherein the plurality of predetermined MCS combinations for subcarrier allocation are limited to an integer number of coded bits per OFDM symbol Ncbps and an integer number of data bits per OFDM symbol Ndbps.

9. The communication station of claim 1, wherein longer duration OFDM symbols are to be selected for larger delay spread environments, and wherein standard duration OFDM symbols are to be selected for legacy communications or smaller delay spread environments.

10. The communication station of claim 1, further comprising one or more processors and memory, and

wherein the physical layer circuitry comprises a transceiver.

11. The communication station of claim 10, further comprising one or more antennas coupled to the transceiver.

12. A method for high efficiency HE wireless communication, comprising:

processing the longer duration OFDM symbol with at least one of:

wherein for binary convolutional code BCC coding, the resource allocation unit is further configured according to one of a plurality of interleaver configurations for subcarrier allocation for conveying longer duration OFDM symbols,

wherein the method further comprises:

13. The method of claim 12, further comprising:

14. The method of claim 12, further comprising: during the control period, a longer duration OFDM symbol including one or more resource allocation units is communicated in accordance with a non-contention based communication technique.

15. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors to perform operations to configure a high efficiency HE communication Station (STA) to:

processing the longer duration OFDM symbol with at least one of:

wherein the operations configure the HEW communication station to:

16. The non-transitory computer-readable storage medium of claim 15, wherein the symbol duration of the longer-duration OFDM symbol is four times as long as a standard OFDM symbol duration, and

wherein the operations further configure the HEW communication station to: during the control period, a longer duration OFDM symbol including one or more resource allocation units is communicated in accordance with a non-contention based communication technique.

17. An apparatus for high efficiency HE wireless communication, comprising:

means for communicating longer duration orthogonal frequency division multiplexing, OFDM, symbols on channel resources according to an orthogonal frequency division multiple access, OFDMA, technique, the channel resources comprising one or more resource allocation units, each resource allocation unit comprising a predetermined number of data subcarriers;

means for configuring the resource allocation unit for communicating longer duration OFDM symbols in accordance with one of a plurality of subcarrier allocations; and

means for processing longer duration OFDM symbols with at least one of:

wherein the apparatus further comprises:

means for processing longer duration OFDM symbols for a single subscriber station using a 512-point FFT for communications within a 40MHz resource allocation unit;

means for processing longer duration OFDM symbols for a single subscriber station using a 1024-point FFT for communications within an 80MHz resource allocation unit; and

means for processing longer duration OFDM symbols for two subscriber stations using a 512-point FFT for communications within an 80MHz resource allocation unit.

18. The apparatus of claim 17, further comprising:

means for processing longer duration OFDM symbols received within a 40MHz resource allocation unit from one or two subscriber stations using a 512 point FFT; and

means for processing longer duration OFDM symbols received within a 20MHz resource allocation unit from one subscriber station using a 256-point FFT.

19. The apparatus of claim 17, further comprising: means for communicating a longer duration OFDM symbol including one or more resource allocation units according to a non-contention based communication technique during a control period.