Simultaneous transmission in multiple frequency segments

1. A method for simultaneously transmitting in a plurality of frequency segments, comprising:

determining, at a communication device, whether simultaneous transmissions in a first frequency segment and a second frequency segment are to be synchronized in time;

in response to the communication device determining that simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized in time,

transmitting a first packet in the first frequency segment beginning at a first time, and

transmitting a second packet in the second frequency segment beginning at the first time; and

in response to the communication device determining that simultaneous transmissions in the first frequency segment and the second frequency segment are to be unsynchronized in time,

transmitting a third packet in the first frequency segment beginning at a second time, and

transmitting a fourth packet in the second frequency segment beginning at a third time that is different than the second time.

2. The method of claim 1 , wherein determining whether simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized in time comprises:

determining whether simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized in time based on a frequency bandwidth of a frequency gap between the first frequency segment and the second frequency segment.

3. The method of claim 2 , wherein determining whether simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized in time comprises:

comparing, at the communication device, the frequency bandwidth of the frequency gap to a threshold;

determining that simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized in time in response to determining that the frequency bandwidth of the frequency gap is less than the threshold; and

determining that simultaneous transmissions in the first frequency segment and the second frequency segment are to be unsynchronized in time in response to determining that the frequency bandwidth of the frequency gap is greater than the threshold.

4. The method of claim 1 , wherein determining whether simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized in time comprises:

determining whether simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized in time based on capabilities of one or more other communication devices that are to receive the simultaneous transmissions.

5. The method of claim 4 , wherein determining whether simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized in time comprises:

determining whether any of the one or more other communication devices are not capable of processing unsynchronized transmissions in multiple frequency segments;

determining that simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized in time in response to determining that at least one of the one or more other communication devices is not capable of processing unsynchronized transmissions in multiple frequency segments; and

determining that simultaneous transmissions in the first frequency segment and the second frequency segment are to be unsynchronized in time in response to determining that all of the one or more other communication devices are capable of processing unsynchronized transmissions in multiple frequency segments.

6. The method of claim 1 , wherein determining whether simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized comprises:

determining whether simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized based on one or more of i) an overall frequency bandwidth of the first frequency segment, ii) an overall frequency bandwidth of the second frequency segment, and iii) a cumulative frequency bandwidth of the overall frequency bandwidth of the first frequency segment and the overall frequency bandwidth of the second frequency segment.

7. The method of claim 1 , further comprising:

generating the first packet to have a first physical layer (PHY) preamble with a first duration; and

generating the second packet to have a second PHY preamble with a second duration that is different than the first duration.

8. The method of claim 7 , further comprising:

generating the first PHY preamble to include different information than the second PHY preamble.

9. The method of claim 1 , generating the second packet comprises:

generating the second packet to include a packet extension field so that transmission of the second packet ends when transmission of the first packet ends.

10. The method of claim 1 , wherein:

when the first packet and the second packet are transmitted:

generating, at the communication device, a first medium access control (MAC) layer data unit,

generating the first packet to include the first MAC layer data unit,

generating, at the communication device, a second MAC layer data unit,

generating the second packet to include the second MAC layer data unit; and

when the third packet and the fourth packet are transmitted:

generating, at the communication device, a third MAC layer data unit,

generating the third packet to include the third MAC layer data unit,

generating, at the communication device, a fourth MAC layer data unit,

generating the second packet to include the fourth MAC layer data unit.

11. The method of claim 1 , wherein:

when the first packet and the second packet are transmitted:

transmitting the first packet via a first number of spatial streams, and

transmitting the second packet via a second number of spatial streams that is different than the first number of spatial streams; and

when the third packet and the fourth packet are transmitted:

transmitting the third packet via a third number of spatial streams, and

transmitting the fourth packet via a fourth number of spatial streams that is different than the third number of spatial streams.

12. A communication device, comprising:

a wireless network interface device comprising:

one or more integrated circuit (IC) devices, and

a plurality of radio frequency (RF) radios including at least a first RF radio and a second RF radio, wherein the plurality of RF radios are implemented at least partially on the one or more IC devices;

wherein the one or more IC devices are configured to:

determine whether simultaneous transmissions in a first frequency segment and a second frequency segment are to be synchronized, and

in response to the communication device determining that simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized,

control the first RF radio to transmit a first packet in the first frequency segment beginning at a first time, and

control the second RF radio to transmit a second packet in the second frequency segment beginning at the first time; and

wherein the one or more IC devices are further configured to:

in response to the communication device determining that simultaneous transmissions in the first frequency segment and the second frequency segment are to be unsynchronized,

control the first RF radio to transmit a third packet in the first frequency segment beginning at a second time, and

control the second RF radio to transmit a fourth packet in the second frequency segment beginning at a third time that is different than the second time.

13. The communication device of claim 12 , wherein the one or more IC devices are further configured to:

determine whether simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized based on a frequency bandwidth of a frequency gap between the first frequency segment and the second frequency segment.

14. The communication device of claim 13 , wherein the one or more IC devices are further configured to:

compare the frequency bandwidth of the frequency gap to a threshold;

determine that simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized in response to determining that the frequency bandwidth of the frequency gap is less than the threshold; and

determine that simultaneous transmissions in the first frequency segment and the second frequency segment are to be unsynchronized in response to determining that the frequency bandwidth of the frequency gap is greater than the threshold.

15. The communication device of claim 12 , wherein the one or more IC devices are further configured to:

determine whether simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized based on capabilities of one or more other communication devices that are to receive the simultaneous transmissions.

16. The communication device of claim 12 , wherein the one or more IC devices are further configured to:

determine whether simultaneous transmissions in the first frequency segment and the second frequency segment are to be synchronized based on one or more of i) an overall frequency bandwidth of the first frequency segment, ii) an overall frequency bandwidth of the second frequency segment, and iii) a cumulative frequency bandwidth of the overall frequency bandwidth of the first frequency segment and the overall frequency bandwidth of the second frequency segment.

17. The communication device of claim 12 , wherein the one or more IC devices are further configured to:

generate the first packet to have a first physical layer (PHY) preamble with a first duration; and

generate the second packet to have a second PHY preamble with a second duration that is different than the first duration.

18. The communication device of claim 17 , wherein the one or more IC devices are further configured to:

generate the first PHY preamble to include different information than the second PHY preamble.

19. The communication device of claim 12 , wherein the one or more IC devices are further configured to:

generate the second packet to include a packet extension field so that transmission of the second packet ends when transmission of the first packet ends.

20. The communication device of claim 12 , wherein the one or more IC devices are further configured to:

when the first packet and the second packet are transmitted:

generate a first medium access control (MAC) layer data unit,

generate the first packet to include the first MAC layer data unit,

generate a second MAC layer data unit, and

generate the second packet to include the second MAC layer data unit; and

when the third packet and the fourth packet are transmitted:

generate a third MAC layer data unit,

generate the third packet to include the third MAC layer data unit,

generate a fourth MAC layer data unit, and

generate the second packet to include the fourth MAC layer data unit.

21. The communication device of claim 20 , wherein the wireless network interface device comprises:

a single media access control (MAC) layer processor implemented on the one or more IC devices;

a baseband signal processor implemented on the one or more IC devices, wherein the baseband signal processor is coupled to the single MAC processor and to the plurality of RF radios; and

wherein when the first packet and the second packet are transmitted:

the single MAC layer processor is configured to generate the first MAC layer data unit and the second MAC layer data unit, and

the baseband processor is configured to generate the first packet and the second packet;

wherein when the third packet and the fourth packet are transmitted:

the single MAC layer processor is configured to generate the third MAC layer data unit and the fourth MAC layer data unit, and

the baseband processor is configured to generate the third packet and the fourth packet.

22. The communication device of claim 12 , wherein the one or more IC devices are further configured to:

when the first packet and the second packet are transmitted:

control the first RF radio to transmit the first packet via a first number of spatial streams, and

control the second RF radio to transmit the second packet via a second number of spatial streams that is different than the first number of spatial streams; and

when the third packet and the fourth packet are transmitted:

control the first RF radio to transmit the third packet via a third number of spatial streams, and

control the second RF radio to transmit the fourth packet via a fourth number of spatial streams that is different than the third number of spatial streams.