A low-power and low-complexity baseband processor for MIMO-OFDM WLAN systems

This paper presents an energy-efficient design and the implementation results of a high speed two transmitter-two receiver multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) wireless LAN baseband processor. The proposed processor includes a bit-parallel processing physical layer convergence procedure (PLCP) processor which lowers system clock frequency. A cost-efficient MIMO spatial multiplexing (SM) symbol detector is also proposed in a physical medium dependent (PMD) processor. The proposed symbol detection algorithm is based on a sorted QR decomposition (SQRD) scheme followed by a maximum-likelihood (ML) test. The proposed algorithm shows enhanced performance compared to the conventional algorithms such as SQRD and ordered successive interference cancellation (OSIC) algorithms. The proposed baseband processor supports a maximum data rate of 130 Mbps at a 40 MHz operation frequency. The power consumptions of the PLCP processor are 27 mW and 93 mW for TX and RX modes, respectively, which are reduced by 70% compared with that of a common bit-serial architecture. The complexity of the symbol detector in the PMD processor is reduced by 18% compared with that of the conventional hardware architecture.