| 摘要 |
In adaptive Multi-Carrier (MC) Orthogonal Frequency Division Multiple Access (OFDMA) communication involving error correction coding, the pilot pattern and spreading factor are varied in order to adapt transmission performance. A denser pilot pattern, where the pilot signals are more closely spaced in time and frequency, models the channel more accurately but leaves less capacity for data. The error in the coded signal is calculated at the transmitting base station from the separation (in time or frequency) of each subcarrier from the closest pilot signal, using the indices and Signal to Noise Ratio (SNR) of the subchannels fed back from each mobile receiver and the calculated pairwise error probability (PEP) or Bit Eror Rate (BER) of a given code. The channel coding can be Turbo coding (PEP = equation 8) or convolutional coding (PEP = equation 13). |
