In the last five years, transmissions using multiple sensors at both ends of the link have been a major research topic. Many transmission schemes are studied such as point to point links using diversity coding, point to point links using multiplexing, tradeoffs between both and at last multi-point to point links. This last scheme was already covered by Space Division Multiple Access (SDMA) processing but a step forward was made with multiple subscriber detection. This paper asses the multi-point to point links for uplink and point to multi-point for the downlink based on OFDM waveform in the frame of the Wireless Metropolitan Area Network (WMAN) IEEE Std 802.16-2004 or HIPERMAN standard. It describes a realistic implementation of transceivers for Physical (PHY) layer to Medium Access Control (MAC) layer allowing a system capacity increase with minor modifications of the standard and with a low impact on the complexity of the subscriber equipment. In this context, this paper proposes to focus on based-band techniques: The Obèle algorithm based on the channel knowledge in the downlink and multiple-user detection in the uplink. The algorithm complexity and the tradeoffs for implementation are extensively discussed.