More of the carriers are dedicated to pilot signals for increased robustness.
Four subcarriers are dedicated to pilot signals, DC subcarrier is not used, and the remaining subcarriers are dedicated to frequency guards.
The energy overhead dedicated to pilots is counted within E b /N 0. First, we investigate the performance of the proposed joint detection algorithm in AWGN channel.
The pilot configuration is comb-type (i.e., a given sub-carrier is dedicated to pilots ∀n), the correlation induced between pilots is such that pn,k = pn + 2, k + 210, the pilots are BPSK symbols.
In the IEEE 802.16e standard the specific size of the MRU varies according to the permutation scheme; concretely for the Band AMC it may take the shapes,, or (subcarriers time symbols, resp ., where 1/9 of the subcarriers are dedicated to pilots.
By normalizing the power of pilot symbols, one can easily distribute the power when total power dedicated to the pilot symbols is given.
In the two designs, total power dedicated to the pilot symbols is the same.
Although the proposed concept can be applied to any CR systems using pilot signal on a specific channel, for the purpose of convenient description, we in this paper consider only the OFDMA-based CR system such as IEEE 802.22 [1], where some subcarriers are dedicated to the pilot signal.
They were dedicated to mistakes that pilots made, so that pilots like myself could learn from those lessons.
This advantage is almost completely used up when channel estimation takes place because in OFDM all the pilot power is used but in FBMC part of it is dedicated to the auxiliary pilot, which does not contribute to the actual estimation.
