A High Throughput Technique for OFDM Systems

The traditional approach for MAC protocols (Medium Access Control) is to discard all packets involved in a collision and request their retransmission, which precludes high throughputs. However, since the signals associated to collisions have important information concerning the packets involved, with proper retransmissions we can efficiently resolve collisions. In this paper we propose a multipacket detection technique for OFDM schemes (Orthogonal Frequency Division Multiplexing) that allows an efficient packet separation in the presence of collisions. This technique allows high throughputs, since the total number of transmissions can be equal to the number of packets involved in the collision. By using different interleavers for different retransmissions we can successfully separate packets involved in a collision even when the channel remains fixed for the retransmissions.