27-09-2016, 02:28 PM
3GPP Long Term Evolution (LTE) Based Cooperative
Communication in Wireless Sensor Networks
1456378211-3GPPLongTermEvolutionLTEBasedCooperative.pdf (Size: 422.12 KB / Downloads: 4)
Abstract— In recent years, secure, reliable and high
speed data transmission have become key elements for
cooperative based communication systems. Conventional
communication methods are no longer sufficiently fulfilling the
demands of next generation communication systems. In this
paper, in order to establish communication between sensor nodes
with the 3GPP LTE standard and achieve better communication
values in terms of low Signal to Noise Ratio (SNR) regimes, four
different Multi-Carrier modulation scenarios were investigated
for relay network configuration of Wireless Sensor Networks’
(WSNs) Physical Layer (PHY). Orthogonal Frequency Division
Multiple Access (OFDMA) and Single Carrier Frequency
Division Multiple Access (SC-FDMA) modulation techniques
were selected due to their wide usage areas in broadband
wireless communication as LTE. Optimal simulation results were
achieved when the SC-FDMA was employed for all relay
network configurations.
INTRODUCTION
Wireless sensor networks (WSNs) [1] have become very
popular in recent years due to their wide usage areas in all
aspects of human life. In particular, active research has
centered around microelectronics improvements on
dimensions of the sensor node. The ramifications of such
research has applications in the broad categories of military,
environmental, health, and home applications, as proposed in
[1], and for ocean sampling, environmental monitoring,
undersea explorations, disaster preventations, assisted
navigations, distributed tactical surveillance, mine
reconnaissance, underwater acoustic sensor networks (UWASNs)
as described in [2]. And most recently, nanonetworks
have been proposed as in [3]. Despite the common usage areas
of sensor nodes, managing the data flow, communication, and
power limitations are the foremost challenges in distributed
sensor nodes in application areas. To overcome managing the
data flow and communication challenges on sensor nodes,
cooperative communication (CC) has been proposed [4]. CC enables the use of relay nodes very efficiently. At each relay
node, the signal becomes more clear and robust due to each
node sharing its resources between the other nodes. In
literature, many CC protocols are proposed to optimize the
relay, including Amplify-and-forward (AF), Decode-andforward
(DF), Compress-and-forward (CF), and Filter-andforward
(FF), among others. Many researchers are dealing
with power limitations and reducing the power consumptions
on each sensor relay node. For instance, in [5], the authors
studied the effect of coding techniques on multihop sensor
networks in low power regimes, while in [6], the authors
propose a method for optimizing the energy consumption in
cooperative based communication in WSNs. As another
example, in [7], the authors offer a novel protocol that is an
energy-efficient cooperative communication model in order to
ensure reliable data transmission in low power regimes. And
finally in [8], the authors applied error-correction codes which
are LDPC codes for channel coding process in order to
minimize the power consumption in WSNs. Along the same
vein, this paper investigates reducing the total power
consumption using 3GPP LTE’s PHY multicarrier modulation
techniques, which are successfully being used in 3G and 4G
communication systems, and its application to cooperative
based WSNs to communicate and increase the data
transmission speeds between each sensor node in low Signal
to Noise Ratio (SNR) regimes.
The remainder of this paper is organized as follows. In
Section II, Multicarrier modulation techniques, which are
Orthogonal Frequency Division Multiple Access (OFDMA)
and Single Carrier Frequency Division Multiple Access (SCFDMA),
are briefly explained, with an emphasis on the
transmitter and receiver structures. In Section III, the proposed
cooperative communication model is explained in detail. In
Section IV, the main results are presented with graphics and
numerical comparisons tables. Finally, the paper is concluded
in Section V.
MULTICARRIER MODULATION TECHNIQUES
OFDMA and SC-FDMA are two prominent multi carrier
modulation techniques used in broadband wireless
communication, such as LTE. Orthogonal Frequency Division
Multiplexing (OFDM) is an outstanding multicarrier
modulation technique which commonly takes part in wireless
communication. OFDMA is the multiuser access version of
OFDM which is used in both downlink and uplink
communication in contemporary communication and in
downlink communication for LTE 3GPP [9-10]. The main
advantage of OFDMA stems from the fact that it converts a
frequency selective larger channel into flat fading narrower
parallel channels to be robust to frequency selectivity. Due to
its use of orthogonal carriers, it does not mandate guard bands
among its carriers. The OFDMA transmitter structure can be
explained as follows. The transmitter firstly converts serial
data input to the parallel as xK, and then applies signal
constellation mapping to obtain xK. Depending on available
spectrum, an M point Inverse Discrete Fourier Transform
(IDFT) is applied to have a time domain representation of
signals as xK by matching M subcarriers with data blocks.
Then, a cyclic prefix (CP) is added to data blocks to prevent
Inter Block Interference (IBI) among carriers, and pulse
shaping is done finally before parallel to serial conversion [9].
OFDMA signal generation at the transmitter can be depicted
as shown in Figure 1.