Performance comparisons between slotted and unslotted spread spectrum ad hoc networks

Slotted and unslotted spread spectrum ad hoc networks are investigated, and the probability of packet successful transmission and the throughput performance are compared between the two kinds of networks in this paper. The expressions of the packet successful transmission probability and the throughput over Rayleigh fading channels are derived, and the impacts of forward error correction (FEC) coding scheme on the network performance are quantitatively analyzed. It is shown that, a significant improvement of the network performance can be obtained by using FEC coding scheme for these two systems. In addition, with the same FEC coding, the network performance of unslotted networks is slightly inferior to that of slotted networks, however, the performance degradation caused by unslotted access can be compensated by introducing FEC coding scheme in spread spectrum ad hoc networks.