Route compaction for directional route discovery in MANETs

Route discovery in reactive routing protocols for MANETs use flooding to disseminate route requests. Such operations rely on MAC level broadcasts to reach all nearby nodes without prior knowledge of their identity. For networks with directional antennas, this creates the following challenge: only neighbors in omni-directional range are discovered, leading to long paths and suboptimal operation. To address this problem sweeping directional MAC broadcasts are often used. Sweeping broadcasts have a high overhead; in addition, we observe that they can cause suboptimal route discovery, especially under high loads. To address these shortcomings, we propose a new directional route discovery approach called route compaction. Route compaction relies on enhanced version of omni-directional route discovery to find paths, avoiding the problems with sweeping broadcast. Route compaction then attempts to compact routes by replacing multiple hops with a single directional hop whenever possible. Our experiments show that this approach provides excellent directional route discovery capability at a lower overhead than sweeping broadcast.