This has been discussed here: Re: WI-FI Speed limit Issues on BCM943362WCD4_EVB
Since most WICED solutions are actually leveraged as Partner Modules with onboard CPUs and somewhat limited serial access, more realistic partner module performance numbers are discussed here: BCM43362 Modules Throughput
Thanks for the reply.
As per the link 'http://community.broadcom.com/message/6865#6865' , 30-40Mb/s through the SDIO interface is possible using SN8000 (external MCU). Is it possible to achieve this with STM32F4 series MCU?