Tone block allocation for orthogonal frequency division multiple access data unit

1. A method, comprising:

selecting, for a first group of devices having a first group size of a plurality of potential group sizes, a set of block allocations from a codebook, the codebook having respective sets of block allocations corresponding to each of the plurality of potential group sizes, wherein the selected set of block allocations is selected to correspond to the first group size;

selecting a block allocation for the first group of devices from the selected set of block allocations, the selected block allocation indicating a respective set of orthogonal frequency division multiplexing (OFDM) tone blocks to be assigned to each device of the first group of devices, each set of OFDM tone blocks indicating a respective integer number of different OFDM tone blocks of a wireless local area network (WLAN) communication channel, wherein selecting the block allocation comprises selecting the integer number of different OFDM tone blocks from a numerically ordered set of integers having at least two non-sequential integer values;

assigning, to each device of the first group of devices, the corresponding integer number of different OFDM tone blocks of the selected block allocation, wherein the selected block allocation includes at least i) a first set of OFDM tone blocks assigned to a first device of the first group of devices and ii) a second set of OFDM tone blocks assigned to a second device of the first group of devices; and

generating an orthogonal frequency division multiple access (OFDMA) data unit to be transmitted to the first group of devices via the WLAN communication channel using the assigned set of OFDM tone blocks, the OFDMA data unit including a preamble portion and a data portion, the preamble portion having an index to the codebook that indicates i) the first group size, and ii) the selected block allocation.

2. The method of claim 1 , wherein each of the sets of OFDM tone blocks to be assigned indicates a contiguous block of OFDM tones.

3. The method of claim 1 , wherein the preamble portion includes a sub-field, having a respective device identifier, for each device of the first group of devices in a same order as the sets of OFDM tone blocks of the selected block allocation.

4. The method of claim 1 , wherein generating the OFDMA data unit comprises iteratively determining the index to the codebook.

5. The method of claim 4 , wherein iteratively determining the index to the codebook comprises performing a plurality of lookups into a table of binomial coefficients.

6. The method of claim 5 , wherein:

iteratively determining the index comprises determining the index as

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where I is the index, n is the first group size, a 3 is a value of the j-th integer number of different tone blocks for the selected block allocation, and j is an index, and

the codebook corresponds to an ordered list of the block allocations of the sets of block allocations for the plurality of potential group sizes.

7. The method of claim 1 , further comprising concurrently receiving i) a first portion of a subsequent OFDMA data unit from the first device using the first set of OFDM tone blocks, and ii) a second portion of the subsequent OFDMA data unit from the second device using the second set of OFDM tone blocks.

8. The method of claim 1 , wherein:

each set of block allocations of the codebook includes block allocations that span a same bandwidth BW,

the WLAN communication channel spans a bandwidth m*BW, where m is a suitable positive integer, and

selecting the block allocation for the first group of devices comprises selecting m block allocations from the codebook for the first group of devices.

9. The method of claim 1 , wherein each OFDM tone block includes a single OFDM sub-carrier.

10. An apparatus, comprising:

a network interface device having one or more integrated circuits configured to:

select, for a first group of devices having a first group size of a plurality of potential group sizes, a set of block allocations from a codebook, the codebook having respective sets of block allocations corresponding to each of the plurality of potential group sizes, wherein the selected set of block allocations is selected to correspond to the first group size,

select a block allocation for the first group of devices from the selected set of block allocations, the selected block allocation indicating a respective set of orthogonal frequency division multiplexing (OFDM) tone blocks to be assigned to each device of the first group of devices, each set of OFDM tone blocks indicating a respective integer number of different OFDM tone blocks of a wireless local area network (WLAN) communication channel, wherein selecting the block allocation comprises selecting the integer number of different OFDM tone blocks from a numerically ordered set of integers having at least two non-sequential integer values,

assign, to each device of the first group of devices, the corresponding integer number of different OFDM tone blocks of the selected block allocation, wherein the selected block allocation includes at least i) a first OFDM tone block set assigned to a first device of the first group of devices and ii) a second OFDM tone block set assigned to a second device of the first group of devices, and

generate an orthogonal frequency division multiple access (OFDMA) data unit to be transmitted to the first group of devices via the WLAN communication channel using the assigned OFDM tone block sets, the OFDMA data unit including a preamble portion and a data portion, the preamble portion having an index to the codebook that indicates i) the first group size, and ii) the selected block allocation.

11. The apparatus of claim 10 , wherein each set of OFDM tone blocks to be assigned indicates a contiguous block of OFDM tones.

12. The apparatus of claim 10 , wherein the preamble portion includes a sub-field, having a respective device identifier, for each device of the first group of devices in a same order as the sets of OFDM tone blocks of the selected block allocation.

13. The apparatus of claim 10 , wherein:

the one or more integrated circuits are configured to iteratively determine the index as

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where I is the index, n is the first group size, a 3 is a value of the j-th integer number of different tone blocks for the selected block allocation, and j is an index, and

the codebook corresponds to an ordered list of the block allocations of the sets of block allocations for the plurality of potential group sizes.

14. The apparatus of claim 10 , wherein the one or more integrated circuits are configured to concurrently receive i) a first portion of a subsequent OFDMA data unit from the first device using the first OFDM tone block set, and ii) a second portion of the subsequent OFDMA data unit from the second device using the second OFDM tone block set.

15. A method, comprising:

receiving an orthogonal frequency division multiple access (OFDMA) data unit via a wireless local area network (WLAN) communication channel;

decoding a non-legacy signal field of the OFDMA data unit to determine a codebook index;

determining a number of devices in a group of devices associated with the OFDMA data unit based on the codebook index;

determining a block allocation based on the codebook index, the block allocation indicating respective sets of OFDM tone blocks for the WLAN communication channel that are assigned to each device of the group of devices, wherein each set of OFDM tone blocks indicates a respective integer number of different OFDM tone blocks of the WLAN communication channel, and the integer number of different OFDM tone blocks is selected from a numerically ordered set of integers having at least two non-sequential integer values;

determining an assigned set of OFDM tone blocks based on the block allocation; and

decoding a data portion of the OFDMA data unit using the assigned set of OFDM tone blocks.

16. The method of claim 15 , wherein determining the number of devices comprises iteratively comparing the codebook index with a size of a set of block allocations, the set of block allocations including block allocations having a same number of sets of OFDM tone blocks.

17. The method of claim 16 , wherein determining the block allocation comprises iteratively determining a set of OFDM tone blocks for each device of the group of multiple devices based on the codebook index.

18. The method of claim 15 , further comprising transmitting a subsequent OFDMA data unit using the assigned tone block set.

19. An apparatus, comprising:

a network interface device having one or more integrated circuits configured to:

receive an orthogonal frequency division multiple access (OFDMA) data unit via a wireless local area network (WLAN) communication channel,

decode a non-legacy signal field of the OFDMA data unit to determine a codebook index,

determine a number of devices in a group of devices associated with the OFDMA data unit based on the codebook index,

determine a block allocation based on the codebook index, the block allocation indicating respective sets of OFDM tone blocks for the WLAN communication channel that are assigned to each device of the group of devices, wherein each set of OFDM tone blocks indicates a respective integer number of different OFDM tone blocks of the WLAN communication channel, and the integer number of different OFDM tone blocks is selected from a numerically ordered set of integers having at least two non-sequential integer values,

determine an assigned set of OFDM tone blocks based on the block allocation, and

decode a data portion of the OFDMA data unit using the assigned set of OFDM tone blocks.

20. The apparatus of claim 19 , wherein determining the number of devices comprises iteratively comparing the codebook index with a size of a set of block allocations, the set of block allocations including block allocations having a same number of sets of OFDM tone blocks.

21. The apparatus of claim 20 , wherein determining the block allocation comprises iteratively determining a set of OFDM tone blocks for each device of the group of multiple devices based on the codebook index.

22. The apparatus of claim 19 , further comprising transmitting a subsequent OFDMA data unit using the assigned tone block set.