  Visible Light Ad Hoc Networks (LANETs) is being perceived as an emerging
technology to complement Radio Frequency (RF) based ad hoc networks to reduce
congestion in the overloaded RF spectrum. LANET is intended to support
scenarios requiring dense deployment and high data rates. In Visible Light
Communication (VLC), most of the attention has been centered around physical
layer with emphasis on point-to-point communication. In this work, we focus on
designing a routing protocol specifically to overcome the unique challenges
like blockage and deafness that render routes in LANETs highly unstable.
Therefore, we propose a cross-layer optimized routing protocol (VL-ROUTE) that
interacts closely with the Medium Access Control (MAC) layer to maximize the
throughput of the network by taking into account the reliability of routes.
  To accomplish this in a distributed manner, we carefully formulate a Route
Reliability Score (RRS) that can be computed by each node in the network using
just the information gathered from its immediate neighbors. Each node computes
an RRS for every known sink in the network. RRS of a given node can be
considered as an estimate of the probability of reaching a given sink via that
node. The RSS value is then integrated to the utility based three-way handshake
process used by the MAC protocol (VL-MAC) to mitigate the effects of deafness,
blockage, hidden node, and maximize the probability of establishing full-duplex
links. All these factors contribute towards maximizing the network throughput.
Extensive simulation of VL-ROUTE shows 124% improvement in network throughput
over a network that uses Carrier Sense Multiple Access/Collision Avoidance
(CSMA/CA) along with shortest path routing. Additionally, VL-ROUTE also showed
up to 21% improvement in throughput over the network that uses VL-MAC along
with a geographic routing.
