MIMO-OFDM and MAC design for broadband ad hoc network

Multiple input multiple output (MIMO) and orthogonal frequency division multiplexing (OFDM) can be used to boost up capacity for broadband wireless communication. However, it is not easy to generalize these techniques to broadband ad hoc networks since existing medium access control (MAC) schemes are designed to accept only one user in a neighborhood. With MIMO-OFDM, multiple nodes can coexist in the same neighborhood. A transceiver architecture merging MIMO-OFDM and with a novel MAC scheme-multiple antennas receiver initiated busy tone medium access (MARI-BTMA) is proposed in this paper. MARI-BTMA is based on receiver initiated busy tone medium access (RI-BTMA) and uses multiple out of band busy-tones to notify the nodes about the number of users in the system and avoid collision on the same channel. To improve the performance at low traffic loads, an adaptive MARI-BTMA is also proposed. In this paper, both theoretical and numerical analysis of the throughput and delay are presented. Analysis and simulation results show the improved performance of MARI-BTMA compared with RI-BTMA and carrier sensing medium access/collision avoidance (CSMA/CA)