On exploiting idle channels in opportunistic multichannel ALOHA

Opportunistic multichannel ALOHA is a random access protocol that can exploit both multiuser and multichannel diversities by taking the advantage of fading channel. However, this protocol is inefficient as inherited from contention based random access in the sense that there is a noticeable number of idle channels in each time slot. To reduce this wastage, we propose a simple extension to the transmission policy so that these idle channels can be exploited, which in consequence leads to a significant improvement in term of maximum throughput.