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Abstract-A rotator and synthesizer driven (RSD) frequency pre-calibration technique is proposed in this paper for the wireless body area network applications. To overcome the large carrier frequency offset (CFO) and sampling clock offset (SCO) due to a low-cost and low-precision reference clock, the CFO and SCO are estimated from the system downlink process. These estimated CFO and SCO values are provided to a rotator and a synthesizer for signal pre-processing. This RSD concept is evaluated in the proposed WiBoC OFDMA system. The tolerated CFO and SCO ranges are extended to 2.5x of existing wireless systems. This system is designed and simulated in a 90nm technology with 77.5 W computation power overhead.

This paper presents a sub-mW all-digital signal component separator (SCS) with a novel branch mismatch compensation scheme for OFDM LINC transmitters, including a phase calculator and a digital-control phase shifter (DCPS) pair. This chip is manufactured in 90nm standard CMOS process with active area 0.06mm 2 . The DCPS can generate phase-modulated signal at IF 100MHz with 8-bit resolution and RMS error 9.33ps (0.34 ∘ ). The phase calculation can be operated with maximum 50MHz speed at 0.5V supply voltage, resulting in 73.88% power reduction, and the overall SCS power is only 949.5 W. With the aid of this SCS, the branch mismatch compensation scheme provides 0.02dB gain and 0.15 ∘ phase fine-tune resolution. The system EVM with 64-QAM OFDM signals is -29.81dB, and the spectrum can pass the mask test of IEEE 802.11a.