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دانلود مقاله Error Correction Codes in Wireless Sensor Network: An Energy Aware approach انتشار 2010

World Academy of Science, Engineering and Technology
Vol:4 2010-01-26

Mohammad Rakibul Islam

Abstract—Link reliability and transmitted power are two important
design constraints in wireless network design. Error control coding
(ECC) is a classic approach used to increase link reliability and
to lower the required transmitted power. It provides coding gain,
resulting in transmitter energy savings at the cost of added decoder
power consumption. But the choice of ECC is very critical in the
case of wireless sensor network (WSN). Since the WSNs are energy
constraint in nature, both the BER and power consumption has to
be taken into count. This paper develops a step by step approach in
finding suitable error control codes for WSNs. Several simulations are
taken considering different error control codes and the result shows
that the RS(31,21) fits both in BER and power consumption criteria.
Keywords—Error correcting code, RS, BCH, wireless sensor networks
I

دانلود مقاله Datalink Streaming in Wireless Sensor Networks

Raghu K. Ganti, Praveen Jayachandran ∗,
Haiyun Luo, and Tarek F. Abdelzaher

Abstract
Datalink layer framing in wireless sensor networks usually
faces a trade-off between large frame sizes for high
channel bandwidth utilization and small frame sizes for effective
error recovery. Given the high error rates of intermote
communications, TinyOS opts in favor of small frame
sizes at the cost of extremely low channel bandwidth utilization.
In this paper, we describe Seda: a streaming datalink
layer that resolves the above dilemma by decoupling framing
from error recovery. Seda treats the packets from the upper
layer as a continuous stream of bytes. It breaks the data
stream into blocks, and retransmits erroneous blocks only
(as opposed to the entire erroneous frame). Consequently,
the frame-error-rate (FER), the main factor that bounds the
frame size in the current design, becomes irrelevant to error
recovery. A frame can therefore be sufficiently large in
great favor of high utilization of the wireless channel bandwidth,
without compromising the effectiveness of error recovery.
Meanwhile, the size of each block is configured according
to the error characteristics of the wireless channel to
optimize the performance of error recovery. Seda has been
implemented as a new datalink layer in the TinyOS, and evaluated
through both simulations and experiments in a testbed
of 48 MicaZ motes. Our results show that, by increasing the
TinyOS frame size from the default 29 bytes to 100 bytes
(limited by the buffer space at MicaZ firmware), Seda improves
the throughput around 25% under typical wireless
channel conditions. Seda also reduces the retransmission
traffic volume by more than 50%, compared to a frame-based
retransmission scheme. Our analysis also exposes that future
sensor motes should be equipped with radios with more
packet buffer space on the radio firmware to achieve optimal
utilization of the channel capacity.
∗First two authors equally contributed to this work

Keywords
Throughput optimization, datalink layer, reliable communication,
sensor networks, wireless networks

مقاله طراحی نمونه ای از شبکه های حسگربیسیم در حوزه کشاورزی

توضیحات :

دقت در برآورد شرایط محیطی باعث افزایش بازده کشاورزی می شود. این شرایط زمانی و مکانی مختلف متفاوت هستند. در نتیجه بهتر است که عملیات کشاورزی متناسب با شرایط نواحی مختلف‌ مزرعه در هر زمان انجام شود. با افزایش دقت در اندازه‌گیری نقطه به نقطه، بازده افزایش می یابد. جهت دست یابی به اهداف فوق، از ابزارهایی به نام حسگر استفاده می گردد که به وسیله آن ها پارامترهای مختلف محیطی اندازه‌ گرفته می شوند. این حسگرها در گره‌هایی نصب شده‌اند که وظیفه ارسال داده‌های دریافتی را به مرکز اصلی برای نگهداری داده‌‌ها و عکس‌العمل لازم در شرایط خاص بر عهده دارند.

فهرست مطالب :

چکیدهمقدمهمواد و روش هااجزای سخت افزاری گره طراحی شدهکنترل کننده مرکزیحسگر حرارتی DS18B20حسگر رطوبتحسگر نور (شعله)فرستنده و گیرنده بی‌سیمطراحی شبکه حسگر بی‌سیمنتایج و بحثنتیجه‌گیری و پیشنهاداتمنابع

مشخصات :

تعداد صفحات : ۱۴ صفحهنوع فایل : فایل Word

دانلود مقاله Forward Error Correction in Sensor Networks

Jaein Jeong and Cheng Tien Ee
Department of Electrical Engineering and Computer Science
University of California, Berkeley
May 16, 2003

Abstract
In any network, there are two basic methods to recover errorneous packets. One way is to use
Automatic Repeat Request (ARQ), and another is Forward Error Correction (FEC). Since, in sen-
sor networks, power is scarce and is primarily consumed by wireless transmission and reception,
we would prefer to use FEC rather than ARQ. In this paper we determine empirically the error
characteristics of wireless transmission signals, and from that, we implement and evaluate dierent
types of encoding schemes that are shown to be successful in reducing the error rates.

Key words: sensor networks, forward error correction, ChipCon Radio