Carrier frequency offset estimation

1. A method for transmitting a transmission data unit in a communication network, the method comprising:

receiving, at a first communication device and from a second communication device, a synchronization frame having an allocation indicator that indicates a non-overlapping allocation of pilot tones;

generating, by the first communication device, a first transmission data unit that comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols of a non-legacy training field portion and a further plurality of OFDM symbols of a data portion, the plurality of OFDM symbols including only pilot tones corresponding to the non-overlapping allocation of pilot tones, the further plurality of OFDM symbols including only pilot tones corresponding to the non-overlapping allocation of pilot tones; and

transmitting, by the first communication device in response to the synchronization frame and via a multiple input, multiple output (MIMO) communication channel, the first transmission data unit to the second communication device simultaneously with a transmission of a second transmission data unit by a third communication device via the MIMO communication channel, wherein corresponding OFDM symbols of respective non-legacy training field portions and respective data portions of the first transmission data unit and the second transmission data unit include non-overlapping pilot tones according to the non-overlapping allocation, wherein the first transmission data unit and the second transmission data unit occupy a same bandwidth of the MIMO communication channel.

2. The method of claim 1 , wherein transmitting the first transmission data unit comprises:

transmitting the OFDM symbols of the non-legacy training field portion of the first transmission data unit at a first transmit power; and

transmitting the OFDM symbols of the data portion of the first transmission data unit at a second transmit power that is less than the first transmit power.

3. The method of claim 1 , wherein the allocation indicator corresponds to a non-overlapping block allocation of pilot tones.

4. The method of claim 1 , wherein the allocation indicator corresponds to a non-overlapping interleaved allocation of pilot tones.

5. An apparatus, comprising:

a network interface associated with a first communication device, the network interface comprising one or more integrated circuit devices configured to:

receive, from a second communication device, a synchronization frame having an allocation indicator that indicates a non-overlapping allocation of pilot tones;

generate a first transmission data unit that comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols of a non-legacy training field portion and a further plurality of OFDM symbols of a data portion, the plurality of OFDM symbols including only pilot tones corresponding to the non-overlapping allocation of pilot tones, the further plurality of OFDM symbols including only pilot tones corresponding to the non-overlapping allocation, of pilot tones; and

cause the first communication device to transmit, in response to the synchronization frame and via a multiple input, multiple output (MIMO) communication channel, the first transmission data unit fame to the second communication device simultaneously with a transmission of a second transmission data unit by a third communication device via the MIMO communication channel, wherein corresponding OFDM symbols of respective non-legacy training field portions of the first transmission data unit and the second transmission data unit include non-overlapping pilot tones according to the non-overlapping allocation, wherein the first transmission data unit and the second transmission data unit occupy a same bandwidth of the MIMO communication channel.

6. The apparatus of claim 5 , wherein the one or more integrated circuit devices are further configured to:

cause the first communication device to transmit the OFDM symbols of the non-legacy training field portion of the first transmission data unit at a first transmit power; and

cause the first communication device to transmit the OFDM symbols of the data portion of the first transmission data unit at a second transmit power that is less than the first transmit power.

7. The apparatus of claim 5 , wherein the allocation indicator corresponds to a non-overlapping block allocation of pilot tones.

8. The apparatus of claim 5 , wherein the allocation indicator corresponds to a non-overlapping interleaved allocation of pilot tones.

9. A method for transmitting a transmission data unit in a communication network, the method comprising:

receiving, at a first communication device and from a second communication device, a synchronization frame having an allocation indicator that indicates a non-overlapping allocation of pilot tones;

generating, by the first communication device, a first transmission data unit that comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols of a data portion, the plurality of OFDM symbols including only pilot tones corresponding to the non-overlapping allocation of pilot tones; and

transmitting, by the first communication device in response to the synchronization frame and via a multiple input, multiple output (MIMO) communication channel, the first transmission data unit to the second communication device simultaneously with a transmission of a second transmission data unit by a third communication device via the MIMO communication channel, wherein corresponding OFDM symbols of respective data portions of the first transmission data unit and the second transmission data unit include non-overlapping pilot tones according to the non-overlapping allocation, wherein the first transmission data unit and the second transmission data unit occupy a same bandwidth of the MIMO communication channel.

10. The method of claim 9 , wherein:

generating the first transmission data unit that comprises generating a plurality of OFDM symbols of a portion of a physical layer (PHY) protocol preamble; and

transmitting the first transmission data unit comprises:

transmitting OFDM symbols of the portion of the PHY preamble of the first transmission data unit at a first transmit power; and

transmitting OFDM symbols of the data portion of the first transmission data unit at a second transmit power that is less than the first transmit power.

11. The method of claim 10 , wherein generating the plurality of OFDM symbols of the portion of the PHY protocol preamble comprises:

generating the plurality of OFDM symbols of the portion of the PHY protocol preamble to include pilot tones that only correspond to the non-overlapping allocation of pilot tones.

12. The method of claim 9 , wherein:

the allocation indicator corresponds to a non-overlapping block allocation of pilot tones; and

generating the first transmission data unit comprises:

generating the plurality of OFDM symbols of the data portion using the non-overlapping block allocation of pilot tones.

13. The method of claim 9 , wherein:

the allocation indicator corresponds to a non-overlapping interleaved allocation of pilot tones; and

generating the first transmission data unit comprises:

generating the plurality of OFDM symbols of the data portion using the non-overlapping block allocation of pilot tones.

14. An apparatus, comprising:

a network interface associated with a first communication device, the network interface comprising one or more integrated circuit devices configured to:

receive, from a second communication device, a synchronization frame having an allocation indicator that indicates a non-overlapping allocation of pilot tones;

generate a first transmission data unit that comprises a plurality of orthogonal frequency division multiplexing (OFDM) symbols of a data portion, the plurality of OFDM symbols including only pilot tones corresponding to the non-overlapping allocation of pilot tones; and

cause the first communication device to transmit, in response to the synchronization frame and via a multiple input, multiple output (MIMO) communication channel, the first transmission data unit to the second communication device simultaneously with a transmission of a second transmission data unit by a third communication device via the MIMO communication channel, wherein corresponding OFDM symbols of respective data portions of the first transmission data unit and the second transmission data unit include non-overlapping pilot tones according to the non-overlapping allocation, wherein the first transmission data unit and the second transmission data unit occupy a same bandwidth of the MIMO communication channel.

15. The apparatus of claim 14 , wherein the one or more integrated circuit devices are further configured to:

generate a plurality of OFDM symbols of a portion of a physical layer (PHY) protocol preamble of the first transmission data unit;

cause the first communication device to transmit OFDM symbols of the portion of the PHY preamble of the first transmission data unit at a first transmit power; and

cause the first communication device to transmit OFDM symbols of the data portion of the first transmission data unit at a second transmit power that is less than the first transmit power.

16. The apparatus of claim 15 , wherein the one or more integrated circuit devices are further configured to:

generate the plurality of OFDM symbols of the portion of the PHY protocol preamble to include pilot tones that only correspond to the non-overlapping allocation of pilot tones.

17. The apparatus of claim 14 , wherein:

the allocation indicator corresponds to a non-overlapping block allocation of pilot tones; and

the one or more integrated circuit devices are further configured to generate the plurality of OFDM symbols of the data portion using the non-overlapping block allocation of pilot tones.

18. The apparatus of claim 14 , wherein:

the allocation indicator corresponds to a non-overlapping interleaved allocation of pilot tones; and

the one or more integrated circuit devices are further configured to generate the plurality of OFDM symbols of the data portion using the non-overlapping block allocation of pilot tones.