OFDMA subchannel assignment

1. A method comprising:

determining, at an orthogonal frequency division multiplexing (OFDM) transceiver device, a corresponding signal-to-noise ratio (SNR) for each of a plurality of subchannels of an orthogonal frequency division multiplexing OFDM channel for each of a plurality of transmit nodes;

allocating, at the OFDM transceiver device, the plurality of subchannels of the OFDM channel among the plurality of transmit nodes by:

assigning to each transmit node a corresponding subset of buckets of a plurality of buckets, the number of buckets in the subset based on a data rate requirement of the transmit node;

distributing the plurality of subchannels among the plurality of buckets based on the SNRs of the plurality of subchannels; and

for each transmit node, allocating to the transmit node the subchannels distributed to the subset of buckets assigned to the transmit node; and

configuring each transmit node to utilize the subchannels allocated to the transmit node;

wherein assigning to each transmit node a corresponding subset of buckets of the plurality of buckets comprises:

determining a least common multiple for the data rate requirements of the plurality of transmit nodes; and

for each transmit node, assigning a number of buckets based on the data rate requirement of the transmit node and the least common multiple.

2. A method comprising:

determining, at an orthogonal frequency division multiplexing (OFDM) transceiver device, a corresponding signal-to-noise ratio (SNR) for each of a plurality of subchannels of an orthogonal frequency division multiplexing OFDM channel for each of a plurality of transmit nodes;

allocating, at the OFDM transceiver device, the plurality of subchannels of the OFDM channel among the plurality of transmit nodes by:

assigning to each transmit node a corresponding subset of buckets of a plurality of buckets, the number of buckets in the subset based on a data rate requirement of the transmit node,

distributing the plurality of subchannels among the plurality of buckets based on the SNRs of the plurality of subchannels, and

for each transmit node, allocating to the transmit node the subchannels distributed to the subset of buckets assigned to the transmit node; and

configuring each transmit node to utilize the subchannels allocated to the transmit node; and

wherein distributing the plurality of subchannels among the plurality of buckets comprises accumulating a total bit loading of each bucket during distribution of the plurality of subchannels by:

for a bucket with the lowest total bit loading:

selecting, for distribution to the bucket, an available subchannel having the highest SNR for the transmit node associated with the bucket;

determining a bit loading of the selected subchannel; and

increasing the total bit loading of the bucket by the bit loading of the selected subchannel; and

repeating the selecting, determining, and increasing for the bucket with the lowest total bit loading at each repetition until every subchannel has been distributed.

3. The method of claim 2 , wherein configuring each transmit node to utilize the subchannels distributed to the transmit node comprises configuring each transmit node to implement the bit loading determined for each subchannel.

4. The method of claim 2 , further comprising:

after distributing every subchannel to the plurality of buckets:

determining a lowest total bit loading of the plurality of buckets; and

equalizing the total bit loading of the plurality of buckets to the lowest total bit loading by reducing a bit loading of each of one or more subchannels distributed to those buckets having a total bit loading greater than the lowest total bit loading.

5. The method of claim 4 , wherein configuring each transmit node to utilize the subchannels distributed to the transmit node comprises configuring each transmit node to utilize the bit loading determined for each subchannel after equalizing the total bit loading of the plurality of buckets.

6. The method of claim 4 , wherein:

reducing the bit loading of each of the one or more subchannels for equalizing the total bit loading of the plurality of buckets reduces the SNRs of the one or more subchannels; and

the method further comprises:

selecting one or more subchannels of one or more buckets for use as a pilot based on the SNRs of the subchannels after equalizing the total bit loading of the plurality of buckets.

7. The method of claim 6 , wherein selecting the one or more subchannels for use as a pilot comprises:

selecting a subchannel distributed to a bucket for use as a pilot for the bucket responsive to the subchannel having an SNR greater than a specified threshold.

8. The method of claim 7 , wherein selecting the one or more subchannels for use as a pilot comprises selecting up to a specified maximum number of subchannels of a bucket for use as pilots.

9. The method of claim 1 , wherein the OFDM transceiver device is in communication with the plurality of transmit nodes via a coaxial cable network.

10. The method of claim 1 , wherein the OFDM transceiver device is in communication with the plurality of transmit nodes via a wireless network.

11. A device comprising:

a signaling interface to receive orthogonal frequency division multiplexing (OFDM) signaling for an OFDM channel from a plurality of transmit nodes;

an OFDM receiver coupled to the signaling interface, the OFDM receiver to process the OFDM signaling;

a channel allocation module coupled to the OFDM receiver, the channel allocation module to allocate a plurality of subchannels of the OFDM channel among the plurality of transmit nodes by:

determining a corresponding signal-to-noise ratio (SNR) for each of the plurality of subchannels for each transmit node of the plurality of transmit nodes;

assigning to each transmit node a corresponding subset of buckets of a plurality of buckets, the number of buckets in the subset based on a data rate requirement of the transmit node;

distributing the plurality of subchannels among the plurality of buckets based on the SNRs of the plurality of subchannels; and

for each transmit node, allocating to the transmit node the subchannels distributed to the subset of buckets assigned to the transmit node; and

an OFDM transmitter coupled to the signaling interface, the OFDM transmitter to transmit configuration information to the plurality of transmit nodes, the configuration information representing the allocation of the subchannels,

wherein the channel allocation module is to assign each transmit node a corresponding subset of buckets of the plurality of buckets by:

determining a least common multiple for the data rate requirements of the plurality of transmit nodes; and

for each transmit node, assigning a number of buckets based on the data rate requirement of the transmit node and the least common multiple.

12. A device comprising:

a signaling interface to receive orthogonal frequency division multiplexing (OFDM) signaling for an OFDM channel from a plurality of transmit nodes,

an OFDM receiver coupled to the signaling interface, the OFDM receiver to process the OFDM signaling;

a channel allocation module coupled to the OFDM receiver, the channel allocation module to allocate a plurality of subchannels of the OFDM channel among the plurality of transmit nodes by:

determining a corresponding signal-to-noise ratio (SNR) for each of the plurality of subchannels for each transmit node of the plurality of transmit nodes;

assigning to each transmit node a corresponding subset of buckets of a plurality of buckets, the number of buckets in the subset based on a data rate requirement of the transmit node;

distributing the plurality of subchannels among the plurality of buckets based on the SNRs of the plurality of subchannels; and

for each transmit node, allocating to the transmit node the subchannels distributed to the subset of buckets assigned to the transmit node; and

an OFDM transmitter coupled to the signaling interface, the OFDM transmitter to transmit configuration information to the plurality of transmit nodes, the configuration information representing the allocation of the subchannels; and

wherein the channel allocation module is to distribute the plurality of subchannels among the plurality of buckets by:

maintaining a total bit loading of each bucket during distribution of the plurality of subchannels;

for a bucket with the lowest total bit loading:

selecting an available subchannel having the highest SNR for distribution to the bucket;

determining a bit loading of the selected subchannel; and

increasing the total bit loading of the bucket by the bit loading of the selected subchannel; and

repeating the selecting, determining, and increasing for the bucket with the lowest total bit loading at each repetition until every subchannel has been distributed.

13. The device of claim 12 , wherein the channel allocation module further is to:

after distributing every subchannel to the plurality of buckets:

determine a lowest total bit loading of the plurality of buckets; and

equalize the total bit loading of the plurality of buckets to the lowest total bit loading by reducing the bit loading of each of one or more subchannels distributed to those buckets having a total bit loading greater than the lowest total bit loading.

14. The device of claim 13 , wherein:

reducing the bit loading of each of the one or more subchannels for equalizing the total bit loading of the plurality of buckets reduces the SNRs of the one or more subchannels; and

the channel allocation module further is to:

select one or more subchannels of one or more buckets for use as a pilot based on the SNRs of the subchannels after equalizing the total bit loading of the plurality of buckets.

15. The device of claim 14 , wherein the channel allocation module is to select the one or more subchannels for use as a pilot by:

selecting a subchannel distributed to a bucket for use as a pilot for the bucket responsive to the subchannel having an SNR greater than a specified threshold.

16. The device of claim 15 , wherein the channel allocation module is to select the one or more subchannels for use as a pilot by:

selecting up to a specified maximum number of subchannels of a bucket for use as pilots.

17. The device of claim 11 , wherein the signaling interface comprises one of: a coaxial cable interface; and a wireless interface.

18. A non-transitory computer readable storage medium storing a set of executable instructions, the set of executable instructions to manipulate at least one processor to:

determine, for each transmit node of a plurality of transmit nodes, a corresponding signal-to-noise ratio (SNR) for each of a plurality of subchannels of an orthogonal frequency division multiplexing OFDM channel;

allocate the plurality of subchannels of the OFDM channel among the plurality of transmit nodes by:

assigning to each transmit node a corresponding subset of buckets of a plurality of buckets, the number of buckets in the subset based on a data rate requirement of the transmit node;

distributing the plurality of subchannels among the plurality of buckets based on the SNRs of the plurality of subchannels; and

for each transmit node, allocating to the transmit node the subchannels distributed to the subset of buckets assigned to the transmit node; and

generate configuration information for transmission to the plurality of transmit nodes, the configuration information representing the allocation of the subchannels;

wherein the set of executable instructions to manipulate at least one processor to assign to each transmit node a corresponding subset of buckets of the plurality of buckets comprises executable instructions to manipulate at least one processor to:

determine a least common multiple for the data rate requirements of the plurality of transmit nodes; and

for each transmit node, assign a number of buckets based on the data rate requirement of the transmit node and the least common multiple.