Wireless Ad Hoc Network Essay

Chapter 1

Introduction

1.1 Introduction

Wireless ad hoc networks are collection of wireless nodes that communicate directly over a common wireless channel. The nodes are equipped with wireless transceiver. They do not need any additional infrastructure such as base station or wireless access point. Therefore each node does not only play the role of an end station but also acts as a router that sends packets to desired nodes. Ad hoc networks have many applications. Two major applications are crisis management and military operations. Another application of ad hoc network is Bluetooth which is designed for personal use and enables printers, scanners, mobile phones and music player to be connected wireless to a personal network that creates flexibility because it enable devices to move freely between different networks. The main problems in ad hoc networks are routing and characteristic of wireless communication. In infrastructure networks a node can communicate with all nodes in the same cell. In ad hoc a node can communicate with other nodes but a routing algorithm is necessary. The

[1] has proposed that power control is to choose the transmit power level for every packet in a wireless ad hoc network. The per-packet choice is to be guided by several considerations. The choice of transmit power and thus the range affect the traffic carrying capacity of the network and it is shown in that after taking into considerations the additional relaying burden of using small hops versus the interference cause by long hops it is optional to reduce the transmit power level. The choice of power level also affects battery life. Moreover power control affect routing since the range of transmitters depend on the transmit power levels. A further factor to be considered is that power control affects packet end to end latency. With small power levels a packet will take large number of hops which may linearly increase latency due to the packetization delay at each