Method and Apparatus for Asynchronous Orthogonal Frequency Division Multiple Access

A method of transmitting orthogonal frequency division multiple access signals, the method comprising:

• transmitting, at a first network node of a 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 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, and the first and second time-frequency grants are granted by a network coordinator node of the network.

A method of scheduling transmission of orthogonal frequency division multiple access signals, the method performed at a network coordinator node of a network, the method comprising:

• allocating a first time-frequency grant to a first network node of the 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 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;
• 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.

A method of scheduling transmission of orthogonal frequency division multiple access signals, the method comprising:

• allocating a first time-frequency grant to a first network node of the 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 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;
• 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.

An apparatus forming a network node on a 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, 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 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.

An apparatus forming a network node on a 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, 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 a second stream of data at a second network node of the network over a second time interval, and at least one subcarrier in the first set is not in the second set.

An apparatus forming a network coordinator (NC) node on a 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 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.

An apparatus forming a network coordinator (NC) node on a 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 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, 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.