Smoothing filter for MIMO OFDM channel estimation

摘要

In multichannel (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) channel estimation, subcarriers near the edge of a given frequency band can be estimated by extrapolating active subcarriers to produce virtual subcarriers 3a, which are further used to yield a smoothing filter for the initial subcarrier estimate. Active subcarrier information may be simply copied (fig. 4) or Wiener filtered to produce virtual subcarriers, thus requiring no change in the relative filter window or filter coefficients (as required in Fig 2a) and allowing use of a simple, fixed coefficient Finite Impulse Response (FIR) filter.