Method and Apparatus for Asynchronous Orthogonal Frequency Division Multiple Access

1. A method of transmitting asynchronous orthogonal frequency division multiple access signals over a Multimedia over Coax Alliance (MoCA) network, the method comprising: transmitting, at a first network node of the MoCA network, a first stream of data having a first number of symbols over a first time interval using a first set of one or more orthogonal frequency division multiple access (OFDMA) subcarriers; and transmitting, at a second network node of the MoCA network, a second stream of data having a second number of symbols over a second time interval different in duration than the first time interval and overlapping the first time interval, using a second set of one or more OFDMA subcarriers; wherein the first time interval and first set of subcarriers define a first time-frequency grant, the second time interval and second set of subcarriers define a second time-frequency grant, the first and second time intervals end at different times, and the first and second time-frequency grants are granted to the first and second network nodes, respectively, by a network coordinator node of the MoCA network; wherein the first time-frequency grant and second time-frequency grant are for upstream data transmissions; and wherein the network coordinator node schedules upstream data transmissions by network nodes in the MoCA network.

2. The method of claim 1 wherein the first and second time intervals begin at different times.

3. The method of claim 1 wherein the first and second sets of subcarriers are reserved for data of first and second traffic classes, respectively.

4. The method of claim 3 wherein the first traffic class is residential traffic, and the second traffic class is commercial service level agreement (SLA) traffic.

5. The method of claim 1 , further including transmitting, at the second network node, a third stream of data beginning at a symbol boundary succeeding the end of the second time interval; wherein the end of the first time interval is after the end of the second time interval, and the symbol boundary is before the end of the first time interval.

6. The method of claim 5 , wherein the first and second time intervals begin at the same time.

7. A method of transmitting asynchronous orthogonal frequency division multiple access signals over a Multimedia over Coax Alliance (MoCA) network, the method comprising: transmitting, at a first network node of the MoCA network, a first stream of data over a first time interval using a first set of one or more orthogonal frequency division multiple access (OFDMA) subcarriers; and transmitting, at a second network node of the MoCA network, a second stream of data over a second time interval using a second set of one or more OFDMA subcarriers including at least one subcarrier in the first set and at least one subcarrier not in the first set; wherein the first time interval and first set of subcarriers define a first time-frequency grant, the second time interval and second set of subcarriers define a second time-frequency grant, the first and second time intervals end at different times, and the first and second time-frequency grants are granted to the first and second network nodes, respectively, by a network coordinator node of the MoCA network; and wherein the first time-frequency grant and second time-frequency grant are for upstream data transmissions to the network coordinator; and wherein the network coordinator node schedules upstream data transmissions by network nodes in the MoCA network.

8. The method of claim 7 wherein the first time interval borders the second time interval.

9. A method of scheduling transmission of asynchronous orthogonal frequency division multiple access signals over a Multimedia over Coax Alliance (MoCA) network, the method performed at a network coordinator node of the MoCA network, the method comprising: allocating a first time-frequency grant to a first network node of the MoCA network, the first time-frequency grant corresponding to a first time interval and a first set of one or more orthogonal frequency division multiple access (OFDMA) subcarriers; allocating a second time-frequency grant to a second network node of the MoCA network, the second time-frequency grant corresponding to a second time interval, different in duration than the first time interval and overlapping the first time interval, and a second set of one or more OFDMA subcarriers, wherein the first and second time intervals end at different times; transmitting a first message to the first network node specifying the first time-frequency grant; and transmitting a second message to the second network node specifying the second time-frequency grant; wherein the first time-frequency grant and second time-frequency grant are for upstream data transmissions; and wherein the network coordinator node schedules upstream data transmissions by network nodes in the MoCA network.

10. A method of scheduling transmission of asynchronous orthogonal frequency division multiple access signals over a Multimedia over Coax Alliance (MoCA) network, the method comprising: allocating a first time-frequency grant to a first network node of the MoCA network, the first time-frequency grant corresponding to a first time interval and a first set of one or more orthogonal frequency division multiple access (OFDMA) subcarriers; allocating a second time-frequency grant to a second network node of the MoCA network, the second time-frequency grant corresponding to a second time interval, bordering the first time interval, and a second set of one or more OFDMA subcarriers including at least one subcarrier in the first set and at least one subcarrier not in the first set, wherein the first and second time intervals end at different times; transmitting a first message to the first network node specifying the first time-frequency grant; and transmitting a second message to the second network node specifying the second time-frequency grant; wherein the first and second time-frequency grants are granted to the first and second network nodes, respectively, by a network coordinator node of the MoCA network; wherein the first time-frequency grant and second time-frequency grant are for upstream data transmissions; and wherein the network coordinator node schedules upstream data transmissions by network nodes in the MoCA network.

11. An apparatus forming a network node on a Multimedia over Coax Alliance (MoCA) network, said apparatus comprising: a computer processor; a physical layer interface including a transmitter and a receiver, said physical layer interface configured to provide communication between said apparatus and at least one other network node on the network, said at least one other network node including a network coordinator (NC) node; a buffer coupled to said processor, said buffer configured to store schedule orders received from said NC node; a timer; a bus configured to provide communication between said processor, said physical layer interface, said buffer, and said timer; a computer readable storage medium having computer-executable instructions stored tangibly thereon, said instructions when executed causing said processor to transmit upstream, at a time based on the stored schedule orders and the timer, a first stream of data having a first number of symbols over a first time interval using a first set of one or more orthogonal frequency division multiple access (OFDMA) subcarriers; wherein the first burst of data has a different number of symbols than a second burst of data that is transmitted upstream at one of the other network nodes over a second time interval different in duration than the first time interval and overlapping the first time interval, using a second set of one or more OFDMA subcarriers, wherein the first and second time intervals end at different times; and wherein the network coordinator node schedules upstream data transmissions by network nodes in the MoCA network, the upstream data transmissions including the first burst of data and the second burst of data.

12. The apparatus of claim 11 wherein the first and second time intervals begin at different times.

13. The apparatus of claim 11 implemented in a set top box configured to communicate over the network.

14. The apparatus of claim 11 implemented in a television configured to communicate over the network.

15. The apparatus of claim 11 implemented in a DVD or Blu-ray player or recorder.

16. The apparatus of claim 11 implemented in a gaming console.

17. The apparatus of claim 11 implemented in a computer configured to communicate over the network.

18. An apparatus forming a network node on a Multimedia over Coax Alliance (MoCA) network, said apparatus comprising: a computer processor; a physical layer interface including a transmitter and a receiver, said physical layer interface configured to provide communication between said apparatus and at least one other network node on the network, said at least one other network node including a network coordinator (NC) node; a buffer coupled to said processor, said buffer configured to store schedule orders received from said NC node; a timer; a bus configured to provide communication between said processor, said physical layer interface, said buffer, and said timer; a computer readable storage medium having computer-executable instructions stored tangibly thereon, said instructions when executed causing said processor to transmit upstream, at a time based on the stored schedule orders and the timer, a first stream of data over a first time interval using a first set of one or more orthogonal frequency division multiple access (OFDMA) subcarriers; wherein at least one subcarrier in the first set is in a second set of one or more OFDMA subcarriers used for transmitting upstream a second stream of data at a second network node of the MoCA network over a second time interval, the first and second time intervals end at different times, and at least one subcarrier in the first set is not in the second set; and wherein the NC node schedules upstream data transmissions by network nodes in the MoCA network, the upstream data transmissions including the first stream of data and the second stream of data.

19. The apparatus of claim 18 wherein the first time interval borders the second time interval.

20. An apparatus forming a network coordinator (NC) node on a Multimedia over Coax Alliance (MoCA) network, said apparatus comprising: a computer processor; a physical layer interface including a transmitter and a receiver, said physical layer interface configured to provide communication between the NC node, a first recipient network node on the MoCA network, and a second recipient network node on the network; a bus configured to provide communication between said processor and said physical layer interface; a computer readable storage medium having computer-executable instructions stored tangibly thereon, said instructions when executed causing said processor to: transmit a first message to the first recipient network node, the first message allocating to the first recipient node a first time-frequency grant corresponding to a first time interval and a first set of one or more orthogonal frequency division multiple access (OFDMA) subcarriers; transmit a second message to the second recipient node, the second message allocating to the second recipient node a second time-frequency grant corresponding to a second time interval, different in duration than the first time interval and overlapping the first time interval, and a second set of one or more OFDMA subcarriers; wherein the NC node is configured to coordinate asynchronous transmissions for upstream reservation requests of the first and second recipient network nodes received at the receiver, and the first and second time intervals end at different times; wherein the first time-frequency grant and second time-frequency grant are for upstream data transmissions; and wherein the NC node schedules upstream data transmissions by network nodes in the MoCA network.

21. An apparatus forming a network coordinator (NC) node on a Multimedia over Coax Alliance (MoCA) network, said apparatus comprising: a computer processor; a physical layer interface including a transmitter and a receiver, said physical layer interface configured to provide communication between the NC node, a first recipient network node on the MoCA network, and a second recipient network node on the MoCA network; a bus configured to provide communication between said processor and said physical layer interface; a computer readable storage medium having computer-executable instructions stored tangibly thereon, said instructions when executed causing said processor to: transmit a first message to the first recipient network node, the first message allocating to the first recipient node a first time-frequency grant corresponding to a first time interval and a first set of one or more orthogonal frequency division multiple access (OFDMA) subcarriers; transmit a second message to the second recipient node, the second message allocating to the second recipient node a second time-frequency grant corresponding to a second time interval, bordering the first time interval, and a second set of one or more OFDMA subcarriers including at least one subcarrier in the first set and at least one subcarrier not in the first set: wherein the NC node is configured to coordinate asynchronous transmissions for upstream reservation requests of the first and second recipient network nodes received at the receiver, and the first and second time intervals end at different times; wherein the first time-frequency grant and second time-frequency grant are for upstream data transmissions; and wherein the NC node schedules upstream data transmissions by network nodes in the MoCA network.