Mobile Ad Hoc Networks

Introduction

A
mobile ad-hoc network (MANET)
consists of mobile hosts equipped
with wireless communication devices. The transmission of a mobile
host is received by all hosts within its transmission range due to the
broadcast nature of wireless communication and omni-directional
antennae. If two wireless hosts are out of their transmission ranges
in the ad hoc networks, other mobile hosts located between them can
forward their messages, which effectively builds connected networks
among the mobile hosts in the deployed area. Due to the mobility of
wireless hosts, each host needs to be equipped with the capability of
an
autonomous system,
or a routing function without any statically
established infrastructure or centralized administration. The mobile
hosts can move arbitrarily and can be turned on or off without
notifying other hosts. The mobility and autonomy introduces a
dynamic topology of the networks not only because end-hosts are
transient but also because intermediate hosts on a communication path
are transient.

Characteristics

• Operating without a central coordinator
• Multi-hop radio relaying
• Frequent link breakage due to mobile nodes
• Constraint resources (bandwidth, computing power, battery lifetime, etc.)
• Instant deployment

Applications

Major Issues and Challenges

• Hidden terminal problem
• Exposed terminal problem
• Channel efficiency
• Access delay and fairness
• Differential service
• Realistic mobility modeling
• power-aware routing
• Constructing virtual backbone
• Distinguish contention, packet drop, and noise errors
• Security
• Efficient multicasting