A phase compensation scheme using feedback control for IEEE 802.11a receiver

In orthogonal frequency division multiplexing (OFDM) receivers, a phase compensator plays an important role in the provision of good packet error rate (PER) performance in channels with carrier frequency offset. A feedback type phase compensator realizes a less complex OFDM receiver. However, the conventional method has two disadvantages. First, a residual phase distortion proportional to a residual carrier frequency offset remains. Second, the estimated phase distortion may oscillate. Both of them degrade phase compensation accuracy, causing PER performance to deteriorate. We propose a new feedback type compensator which calculates a phase compensation value for pilot subcarriers in order to avoid the oscillation of the estimated phase distortion and another phase compensation value for data subcarriers in order to avoid the residual phase distortion. The proposed method is not subject to the conventional method´s disadvantages and improves the PER performance.