Cross-layer transmission scheduling for direct-sequence spread-spectrum ad hoc networks

We investigate a transmission scheduling protocol that exploits direct-sequence spread-spectrum (DSSS) modulation to improve the performance of a mobile, ad hoc network. Since DSSS allows for packet capture in the presence of other nearby transmissions, multiple-access interference is less detrimental to network performance. We design a new transmission scheduling protocol that takes advantage of the multiple-access capabilities of DSSS through two key features. First, the transmission schedule employs a more aggressive spatial reuse policy. Second, our protocol reduces overhead by accounting for fewer terminals in the scheduling because only the strongest interferers disrupt packet reception. Transmissions use both common and transmitter-oriented spreading codes to support reliable neighbor discovery and broadcast capability, respectively. Spreading factors may be adapted to increase throughput of unicast traffic on links with high SINR. Through simulations, we evaluate the performance of the transmission scheduling protocol in mobile and stationary scenarios.