In this paper, we present a cross-layer optimization scheme to improve the fairness and quality of service (QoS) of wireless ad-hoc network. As for the physical layerÂs information feedback, it is mainly the physical link quality. We adopt multi-access technique such as TDMA and a fusion of technologies, such as Multiple -Input and Multiple-Output (MIMO) and Orthogonal FrequencyDivisionMultiplexing (OFDM). Using multi-user detection to physical link quality, to achieve the joint cross-layer optimization design of PHY-MAC, we propose the MAC protocol with RTS/CTS reservation mechanism based on a distribution of slots (RDTDMA). The objective is to improve energy utilization, reduce bit error rate (BER) and alleviate network congestion effectively. The experimental results showthat the cross-layer optimization can effectively improve the overall performance of wireless ad-hoc network, significantly in energy saving and throughput.