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The advancement in multimedia system triggers the development of the digital television system. A
number of standards have been proposed, such as Digital Video Broadcasting (DVB), Digital Multimedia
Broadcasting (DMB), Integrated Service Digital Broadcasting (ISDB), and Advanced Television Systems
Committee (ATSC) 1. Although there are many available standards, most of the countries around the world
adopted DVB system for their national television system standard. DVB is a suite of internationally accepted
open standards for digital television. DVB standards are maintained by the DVB Project, an international
industry consortium with more than 270 members, and are published by a Joint Technical Committee (JTC) of
the European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical
Standardization (CENELEC) and European Broadcasting Union (EBU). DVB system consists of a number of
approaches in delivering the broadcast content, such as DVB-T/T2 (terrestrial), DVB-S/S2 (satellite), DVB-
C/C2 (cable), DVB-H/SH (handheld). DVB-T was selected in this research due to the free-to-air scheme and
it is still widely used by many operators around the world, although DVB-T2 has been introduced.

The DVB-T system uses MPEG-2 Transport Stream (MPEG-2 TS) as the input stream. This stream
is transmitted over the channel through DVB-T system. During transmission, the stream might be affected by
channel impairments, such as noise, which may decrease the video quality that received by the end user. This
problem must be able to be detected and identified by the DVB-T system in order to maintain the picture quality
in a good condition. One of the solutions in combating such situation is to increase power. However, increasing

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power without monitoring channel condition might lead to power inefficiency. As the channel condition change
over time, thus power adaptation is required in order to maintain power efficiency. Adaptive power control is
part of link adaptation strategy, particularly explicit link adaptation. Link adaptation techniques have gained
increasing attention for improving the quality of wireless multimedia communication schemes 2-4. In explicit
link adaptation, transmission parameters such as the signal power, the modulation constellation, or the amount
of redundancy provided for error control are explicitly adjusted to compensate for the variations in channel
conditions. For these purposes, channel state information (CSI) needs to be estimated at the receiver and then
communicated back to the transmitter 2. This feedback enables the transmitter to adapt transmission
parameters on a regular basis in response to the CSI at the time. In this research, adaptive power control was
selected since it has lower complexity than adaptive modulation and adaptive coding.

Adapting the power of the transmit signal in order to account for signal fades that are caused by
multipath propagation or other channel impairments, results in the channel being used more efficiently. This
can be achieved by controlling the power in such a way that it takes advantage of favorable channel conditions
5. The overall objective of power control is to conserve as much transmit power as possible while at the same
time maintaining satisfactory link quality for a wide range of channel conditions. The advantages of power
control include longer battery life 6 and high resolution with respect to adapting to small variations in the
channel quality. On the other hand, power control techniques may result in an undesirable increase of co-
channel interference. Although power control schemes can be classified in many different ways, the focus of
this research is on metrics that are used to initiate the power control algorithm. There are four different
measurements that can be used to indicate link quality and hence can be deployed with power control
algorithms. These are referred to as strength-based 6, signal-to-interference-ratio (SIR) based 6, BER-based
6 and perceptual quality (PQ) based power control 7.

This paper is organized as follows. In Section 2, research methods, which contain research approach
and design, are discussed. Section 3 presents experiment setup, results from the experiments, and analysis of
the results. Finally, concluding remarks and future works are given in Section 4. 

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