Dynamic subcarrier allocation in Multicarrier Spread Spectrum communication

In Multi-Carrier (MC) Orthogonal Frequency Multiple Access (OFDMA) communication involving error correction coding, subcarriers are allocated to multiple users dynamically (124) by taking account of different user requirements of quality and bandwidth for different transmissions (eg. voice, low-resolution video, broadcast quality video etc.) and the accuracy of those channel models, in order to adapt the spread factor appropriately. Each mobile terminal (300a,b...) subcarrier's index and Signal to Noise Ratio (SNR) are fed back to the transmitter, and the base station estimates the average Pairwise Error Probability (PEP) produced by the decoder for a given candidate set of subcarrier frequency allocations and a predetermined pilot signal sequence, in order to calculate subcarrier allocations such that the bandwidth and quality requirements of all the terminals are met. Joint adaptation of pilot patterns and spreading factors may be necessary to achieve this. The channel coding can be Turbo (PEP = equation 8) or Convolutional (PEP = equation 13) coding, and different scheduling policies (122) can be implemented.