Prototyping of wireless systems gives key insight of the system operation and its performance in a real wireless end-to-end link. The platform provides access to real propagation channels and gives better understanding of the impact of front-end impairments such as phase noise and amplifier non-linearity. In this way it can help the designers to ensure that their system design meets the performance requirements of the wireless LAN standardization committees. We have conceived a generic platform for real time prototyping of broadband WLAN systems. The platform is based on modular multi-FPGA and multi-board concepts with support for high-speed serial connection links between the boards. The hardware and software flexibility of the platform facilitates the extensions towards next generation WLAN standards. This paper describes the implementation of a 54 Mbps single antenna Hiperlan2 wireless LAN user terminal and the implementation of a 2-antenna base station with a downlink capacity of 2 times 54 Mbps. Two realizations of the front-end and their digital compensation techniques are characterized on the platform: a 5 GHz super-heterodyne transceiver and a 5 GHz direct conversion receiver. Finally, a real time WLAN system with Medium Acces Control (MAC) is demonstrated on the platform.