Polar baseband receiver for low-end WLAN

Many modern wireless communication technologies (e.g., WiMAX, LTE, and 802.11a/g/n/ac WLAN) rely on OFDM and support multiple data rates. To make the computational effort of an OFDM-based receiver adjustable to variable data rate requirements, we advocate the use of polar coordinates (i.e., magnitude/angle representation) during baseband processing of complex-valued samples in the frequency domain, as opposed to conventional Cartesian coordinates (i.e., in-phase/quadrature representation). We evaluate our proposed polar receiver in the context of the low-end OFDM-based 802.11a WLAN standard that supports eight data rates: BPSK-modulated 6 and 9 Mbps, QPSK-modulated 12 and 18 Mbps, 16-QAM-modulated 24 and 36 Mbps, and 64-QAM-modulated 48 and 54 Mbps. Our approach reduces the number of required frequency-domain multiplications (i.e., excluding time-domain, FFT, and post-demodulation computations) by at least 53% in comparison to a workload associated with a conventional Cartesian receiver.