This thesis examines a Distributed Interference Impact Probing (DIIP) strategy for
Wireless Ad hoc Networks (WANETs), using a novel cross-layer Minimum Impact
Routing (MIR) protocol. Perfonnance is judged in tenns of interference reduction ratio,
efficiency, and system and user capacity, which are calculated based on the
measurement of Disturbed Nodes (DN). A large number of routing algorithms have
been proposed with distinctive features aimed to overcome WANET's fundamental
challenges, such as routing over a dynamic topology, scheduling broadcast signals using
dynamic Media Access Control (MAC), and constraints on network scalability.
However, the scalability problem ofWANET cannot simply adapt the frequency reuse
mechanism designed for traditional stationary cellular networks due to the relay burden,
and there is no single comprehensive algorithm proposed for it.
DIIP enhances system and user capacity using a cross layer routing algorithm, MIR,
using feedback from DIIP to balance transmit power in order to control hop length,
which consequently changes the number of relays along the path. This maximizes the
number of simultaneous transmitting nodes, and minimizes the interference impact, i.e.
measured in tenns of 'disturbed nodes'. The perfonnance of MIR is examined
compared with simple shortest-path routing. A WANET simulation model is configured
to simulate both routing algorithms under multiple scenarios. The analysis has shown
that once the transmitting range of a node changes, the total number of disturbed nodes
along a path changes accordingly, hence the system and user capacity varies with
interference impact variation. By carefully selecting a suitable link length, the
neighbouring node density can be adjusted to reduce the total number of DN, and
thereby allowing a higher spatial reuse ratio. In this case the system capacity can
increase significantly as the number of nodes increases. In contrast, if the link length is
chosen regardless ofthe negative impact of interference, capacity decreases. In addition,
MIR diverts traffic from congested areas, such as the central part of a network or
bottleneck points.