Gradient based method and apparatus for OFDM sub-carrier power optimization

Apparatus operable to increase data throughput in an orthogonal frequency division multiplex (OFDM) wireless communications system, comprising at least one data processor operating under control of a stored program, and coupled to OFDM transmission circuitry, to model data throughput as a function of received Signal to Noise Ratio (SNR) with a sigmoid function to produce a throughput curve characterized as having a lower knee region and an upper knee region;

• and to perform a gradient ascent search along the throughput curve by varying the power of a plurality of sub-carriers so as to remove power from any sub-carrier having a received SNR to the left of the lower knee region, and to re-allocate the removed power to sub-carriers having a received SNR to the right of the lower knee region.

A computer readable memory medium storing computer program instructions for increasing data throughput in an orthogonal frequency division multiplex (OFDM) wireless communications system, comprising operations of performing a gradient ascent search along a data throughput curve, where the data throughput curve is modeled using a received Signal to Noise Ratio (SNR) as a sigmoid function to produce the data throughput curve to be characterized as having a lower knee region and an upper knee region, said gradient ascent search operating to vary the power of a plurality of sub-carriers so as to remove power from any sub-carrier having a received SNR to the left of the lower knee region, and to re-allocate the removed power to sub-carriers having a received SNR to the right of the lower knee region.

A computer readable memory medium storing computer program instructions for increasing data throughput in an orthogonal frequency division multiplex (OFDM) wireless communications system, comprising operations of performing a multi-stage gradient ascent search along a data throughput curve, where the data throughput curve is modeled using received Signal to Noise Ratio (SNR) as a sigmoid function to produce the data throughput curve to be characterized as having a lower knee region and an upper knee region, said gradient ascent search operating to vary the power of a plurality of sub-carriers so as to remove power from any sub-carrier having a received SNR to the left of the lower knee region, and to re-allocate the removed power to sub-carriers having a received SNR to the right of the lower knee region, where during a first stage of the gradient ascent search an operation identifies sub-carriers to be disabled, and where during a second stage of the gradient ascent search a further operation allocates power only to retained sub-carriers at the expense of disabled sub-carriers.

Apparatus operable to increase data throughput in an orthogonal frequency division multiplex (OFDM) wireless communications system, comprising data processor means operating under control of a stored program, and coupled to OFDM transmission circuitry, for modeling data throughput as a function of received Signal to Noise Ratio (SNR) with a sigmoid function to produce a throughput curve characterized as having a lower knee region and an upper knee region;

• and for performing a gradient ascent search along the throughput curve by varying the power of a plurality of sub-carriers so as to remove power from any sub-carrier having a received SNR to the left of the lower knee region, and to re-allocate the removed power to sub-carriers having a received SNR to the right of the lower knee region.