transmit antenna selection in the cooperative ...the relay assisted two-hop ultra-wideband (uwb)...
TRANSCRIPT
Transmit Antenna Selection in the CooperativeCommunication Based UWB System
A. Agrawal1 • R. S. Kshetrimayum1
Published online: 27 September 2016� Springer Science+Business Media New York 2016
Abstract In this paper, We derived an expression of the average bit error rate (ABER) of
the relay assisted two-hop ultra-wideband (UWB) communication system over IEEE
802.15.3a channel model incorporated with the transmit antenna selection at the source and
relay nodes. In this two-hop system, each node equipped with the multiple antennas and
relay is configured to perform decode and forward protocol. The analysis considers the
numerically evaluated characteristic function of the sum of the path gains, which are
specified in the IEEE 802.15.3a channel model. During the analysis, we assumed that all
the channel links and channel paths are independent and identically distributed. Our result
shows the derived ABER is well matched to the simulation. It also presents the comparison
of the ABER between the investigated and the conventional UWB systems. This paper also
presents the flowchart of the Monte-Carlo simulation of the investigated UWB system.
Keywords Ultra-wideband � Cooperative communication � TAS/MRC � MIMO
1 Introduction
The low cost and high data rate features have drawn the considerable interest towards the
Ultra-wide band (UWB) wireless indoor communication system. It offers extremely wide
bandwidth of 3.1 to 10.6 GHz. In the year 2002, Federal Communication Commission
(FCC) imposed the limit on the allowable power spectral density (PSD) of the UWB signal
to prevent the interference to the existing narrowband wireless communication system
& R. S. [email protected]
1 Department of Electronics and Electrical Engineering, Indian Institute of Technology Guwahati,Guwahati 781039, India
123
Wireless Pers Commun (2017) 94:3001–3015DOI 10.1007/s11277-016-3762-2
[1–3]. This power constraint limits the system coverage area and the transmission data rate.
These limitations of UWB communication system has emerged the idea of incorporating
cooperative relaying scheme in UWB communication systems [4, 5]. The fundamental
concept of the cooperative scheme in the wireless network is the utilization of additional
relay node for transmitting the source (S) information to the destination (D). In general,
cooperative protocol strategy has been categorized into the Amplify-and-Forward (AF) and
the Decode-and-Forward (DF) cooperative strategies. In [6, 7] the authors have proposed
amplify and forward relaying cooperative strategy in the UWB system over the frequency-
flat and frequency-selective fading channels, respectively. In [8], the author has presented a
similar work for the decode and forward relaying scheme over Nakagami-m distributed
fading. In [9], the author equipped the multiple antennas at the relay terminal in the two-
hop UWB system and results show that employing multiple antennas has significantly
improved the performance of the two-hop UWB system over the convention two-hop
UWB. In [10–14], the authors have evaluated the different performance measures i.e., error
performance, channel capacity and outage probability, of the two-hop wireless system with
multiple antennas and the shown results have inspired us to investigate the similar two-hop
UWB system, where each node consist the multiple antennas.
As per our knowledge, no work in the literature has considered the actual IEEE
802.15.3a channel model which is the most appropriate channel model for the indoor UWB
communication system [2]. By deploying the multiple antennas at the S, R and D terminals,
we get the higher diversity gain, achieved larger coverage area and improved the path loss
saving factor. These quality parameters are increases linearly with the number of antennas
in the multiple-input-multiple-output (MIMO) system. The increment in the number of
antennas introduces additional hardware and computational complexities. To address these
issues, in [15–17], authors have suggested the Transmit Antenna Selection (TAS) with
Maximum Ratio Combining (MRC) scheme in the wireless MIMO system.
In this paper, we evaluate the average bit error rate (ABER) of the TAS/MRC based
two-hop UWB-MIMO system over IEEE 802.15.3a channel model. In the investigated
system source and relay terminal perform the TAS scheme in the S–D and R–D links only
while R terminal considered the DF-relaying protocol. The analysis uses the numerically
evaluated CF of the sum of the path gains to derived the density function of the received
SNR. The derived ABER of the investigated UWB system also considered the impact of
fingers of the coherent RAKE receiver. However to find the numerical solutions of the
intractable integrals, involved in this analysis, we use Gauss-Hermite quadrature, Gauss-
Legendre quadrature, and Gauss-Laguerre quadratures formulae.
The remaining part of this paper is organized as follows. The system and channel model
is described in Sect. 2. The theoretical analysis of the investigated UWB is done in
Sects. 3, 4 presents the numerical results and discussion. Finally, the conclusion is drawn
in Sect. 5.
2 System and Channel Model
TAS/MRC based two-hop MIMO system is shown in Fig. 1, where Nt and Nr denote the
number of antennas at the transmitter and at the receiver, respectively.
In this work, source and relay terminals perform the Nt; 1;Nrð Þ TAS/MRC scheme and
select the single transmitting antenna, which maximized the received signal to noise ratio
3002 A. Agrawal, R. S. Kshetrimayum
123
(SNR) at the destination terminal. Suppose ith transmitting antenna account the maximum
SNR, then the decision criteria of the selected antenna is given as [18, 19]
C ið Þ ¼ max1� i�Nt
Ci ¼XNr
v¼1
hi;v�� ��2
( )ð1Þ
where C ið Þ ¼ max1� i�NtCif g and hi;v, 1� i�Nt, 1� v�Nr is the channel impulse
response between the ith transmitting antenna and the vth receiving antenna, is modeled as
IEEE 802.15.3a channel is defined later. According to the order statistics, the probability
density function (PDF) of C ið Þ can be calculated as [20]
fC ið Þ xð Þ ¼ Nt FCi xð Þ½ �Nt�1fCi xð Þ ð2Þ
where fCi :ð Þ is the PDF of Ci and the cumulative density function (CDF), FCi :ð Þ of Ci isdefined as FCi xð Þ ¼
R x0fCi tð Þdt.
Task Group IEEE 802.15.3a (TG3a) has developed the IEEE 802.15.3a channel stan-
dard for the analysis of high-data rate UWB communication system. The IEEE 802.15.3a
channel model is different from the convention narrow-band Saleh-Venezuela (SV) model
because the large available bandwidth and all the multipath coefficients are lognormally
distributed random variables. The impulse response of IEEE 802.15.3a channel model
between the ith transmitting antenna and the vth receiving antenna is given as
hi;vðtÞ ¼ XXM
m¼0
XR
r¼0
ar;md t � Tm � sr;m� �
ð3Þ
where ar;m is the multipath coefficient of the rth ray in the mth cluster, and X is the shadow
fading, are distributed according to the lognormal distribution. Tm and sr;m are the cluster
and the ray arrival times, respectively. The parameters M and R denote the number of
clusters and number of rays in the cluster. On the basis of practical measurement, IEEE
802.15.3a channel model (CM) has been categories into four different channel models.
According to the channel report of the TG3a in [2], the suggested numerical values of
channel parameters for every channel model are given in Table 1.
In the two-hop DF-relaying communication, the transmission is performed in two-time
phases. In the first time phase, source terminal broadcast the information to the destination
and the relay terminals whereas, in the second time phase the R terminal initiate the
transmission to the D terminal only when it decodes the received data correctly. This work
considered that the before initiating the transmission in the source-destination (S–D) and
relay-destination (R–D) links, the S and the R terminals select the ith transmitting antenna
after performing the TAS scheme, while in the source-relay (S–R) link transmission, source
Fig. 1 TAS/MRC based two-hop MIMO system
Transmit Antenna Selection in the Cooperative Communication... 3003
123
terminal uses the same transmitting antenna (ith), which was selected in the (S–D)
transmission. Suppose, x is the transmitted symbol and p1, p2 are the transmitted power at
the S and the R terminals, respectively. Thus, the received signal vectors correspond to the
(S–R), (S–D) and (R–D) links can be expressed as
ySR ¼ ffiffiffiffiffip1
phSRi xþ nSRi ð4Þ
ySD ¼ ffiffiffiffiffip1
phSDðiÞ xþ nSDðiÞ ð5Þ
and
yRD ¼ ffiffiffiffiffip2
phRDðiÞ xþ nRDðiÞ ð6Þ
where y ¼ y1; y2; . . .; yNr
� �Tdenotes the received signal vector and hi ¼
hi;1; hi;2; . . .; hi;Nr
� �Tis the channel impulse response vector corresponds to the Nr antennas.
Similarly, the noise n is the Nr � 1ð Þ AWGN vector with power spectral density N0. The
subscripts i and (i) represent the transmit antenna index and the selected transmit antenna
index after performing the TAS scheme, respectively.
3 Performance Analysis
In this section, we evaluate the ABER of the binary signals of the TAS/MRC based two-
hop UWB system over IEEE 802.15.3a channel model. In the investigated UWB system,
we have considered the decode and forward relaying. Therefore, end-to-end ABER of the
two-hop relaying system can be calculated as [21, 22]
�pe ¼ pe SRð Þ cSRð Þpe SDð Þ cSDð Þ þ pe SRDð Þ cSRDð Þ 1� pe SRð Þ cSRð Þ� �
ð7Þ
where pe SRð Þ :ð Þ; pe SDð Þ :ð Þ; pe SRDð Þ :ð Þ�
are the ABER for the single links from the source to
relay, source to destination and source to destination with relay terminals, respectively.
Similarly, cSR; cSD; cSRDf g are the received SNR for above mentioned links. From [23], the
ABER of the binary signals with coherent RAKE receiver can be computed as
Table 1 Parameters of IEEE 802.15.3a channel models
Model Parameter CM1 CM2 CM3 CM4
Distance (d in m) 0-4 0-4 4-10 � 25
Channel environment LOS NLOS NLOS NLOS
Cluster arrival rate (K in 1/ns) 0.0233 0.4 0.0667 0.0667
Ray arrival rate (k in 1/ns) 2.5 0.5 2.1 2.1
Power delay factor for cluster (C) 7.1 5.5 14.0 24.0
Power delay factor for ray (c) 4.3 6.7 7.9 12
Standard deviation for cluster (r1 in dB) 3.3941 3.3941 3.3941 3.3941
Standard deviation for ray (r2 in dB) 3.3941 3.3941 3.3941 3.3941
Standard deviation for shadowing (rx in dB) 3 3 3 3
3004 A. Agrawal, R. S. Kshetrimayum
123
�pe cð Þ ¼Z1
0
Qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi1� qrð Þc
p �fc cð Þdc ð8Þ
where qr ¼ �1 and qr ¼ 0 for the antipodal and orthogonal binary signals, respectively.
fc cð Þ is the PDF of received SNR cð Þ.
3.1 ABER for the S–R link
In the link, the source terminal uses the same transmitting antenna for transmission which
was selected in the S–D link, while the relay terminal performs the MRC scheme.
Therefore, after performing MRC the received SNR in the S–R link is given as
cSR ¼ p1
N0
XNr
v¼1
eSRi;v
¼ p1
N0
CSRi
ð9Þ
where eSRi;v denotes the received energy at L-RAKE receiver in the single ði� vÞ path of S-Rlink. Under the assumption of i.i.d channel paths, the energy received at one path is
independent to the energy received at the other path. Therefore, the characteristic function
WSRCi sð Þ, of CSRi can be computed as
WSRCi sð Þ ¼
YNr
v¼1
wSRei;v sð Þ ð10Þ
where wSRei;v sð Þ is the characteristic function of eSRi;v and its computation is given in the next
subsection. Now the PDF f SRCi xð Þ, of CSRi can be computed as
f SRCi xð Þ ¼ 12p
R1�1 WSR
Ci sð Þ exp �jsxð Þds. The closed form solution of this integration is
numerically integrated. Thus, using the Gauss-Hermite (GH) quadrature, it can be written
as
f SRCi xð Þ ¼ 1
2p
XNH
k¼1
wHk W
SRCi sð Þ exp s2 � jsx
� ���s¼xH
k
ð11Þ
where fwHk g, fxHk g and NH are the weights, abscissas and number of nodes of the GH
quadrature, respectively. From the Eqs. (8), (9) and (11), and using the Gauss-Laguerre
(GL) quadrature with some computations, the ABER for the S� Rð Þ link is given as
pe SRð Þ cSRð Þ ¼ 1
2p
XMl
q¼1
XNH
k¼1
wlqw
Hk W
SRCi
xHk� �
F p1;N0; xHk ; x
lq; qr
�ð12Þ
where F r1; r2; r3; r4; r5ð Þ ¼ Q
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi1�r5ð Þr1r4
r2
q �e r4 1�jr3ð Þþ r3ð Þ2½ � and fwl
q; xlq;M
lg are the weights,abscissas and number of nodes of GL quadrature, respectively.
Transmit Antenna Selection in the Cooperative Communication... 3005
123
3.2 Computation of the Characteristic Function we sð Þf g, of e
For better understanding, we omit the antennas and the link indexing. In the UWB com-
munication, the total transmitted signal energy is dispersed over the MPCs and these MPCs
can be resolved separately, which provide the higher order of diversity gain. To attain the
diversity gain and collect all the multipath signals, we used L-fingers of the RAKE
receiver. Let us assume that, e is close to the ~e, Now in the 0; LTc½ � time window, the ~e canbe approximately calculated as [24],
~e ¼ X2X
0�Tmþsr;m � LTc
ar;m�� ��2 ¼ X2 a20;0 þ /r;0 þ ~/�
�ð13Þ
where Tc is the chip duration between two consecutive fingers. The parameter a20;0 is the
squared of path gain of first ray in the first cluster, /r;0 is the sum of squared path gains of
the first cluster excluding the a20;0 and~/� is the sum of squared path gains of all the rays in
the remaining clusters. X2 is the square of the shadow fading. According to the TG3a
report, X is a lognormal random variable, i.e. X lnN 0; rxdBð Þ, then X2 lnN 0; 2rxdBð Þ.Thus, the PDF fX2 xð Þ, of X2 can be written as
fX2 xð Þ ¼ 10ffiffiffiffiffiffi2p
prxx lnð10Þ
exp � 10log10xffiffiffi2
prx
� 2 !
ð14Þ
where rx is the standard deviation for the shadow fading defined in Table 1. Let us defined
e0 ¼ a20;0 þ /r;0 þ ~/�, note that the parameters of e0 are statistically independent to each
other. Thus, the characteristic function we0 tð Þ of e0 can be computed as
we0 tð Þ ¼ L0;0ðtÞI tð ÞR tð Þ ð15Þ
where L0;0ðtÞ, I tð Þ and R tð Þ are the characteristic functions of a20;0, /r;0 and ~/�,
respectively. From [26], I tð Þ ¼ e �k ~wt 0;Lð Þð Þ and R tð Þ ¼ e �K~Jðt;LÞð Þ. The functions ~wt 0; Lð Þand ~Jðt; LÞ can be evaluated numerically, e.g., using Gauss-Legendre quadrature, are given
as [26]
~wt T ; Lð Þ LTc � T
2
XNL
b¼1
wLb 1� LT ;tðtÞ� ���
t¼LTc�T2
xLbþLTcþT
2
ð16Þ
and,
~Jðt; LÞ LTc
2
XNL
b¼1
wLb 1�LT ;TðtÞ� �
e �k ~wtðT ;LÞ½ ����T¼LTc
2 xLbþ1ð Þ
ð17Þ
where xLb ;wLb ;N
L�
are the abscissas, weight and number of nodes of Gauss-Legendre
quadrature, respectively. where LT ;tðtÞ is the characteristic function of the square of a
lognormal random variable, can be evaluated using Gauss-Hermite quadrature is given as
3006 A. Agrawal, R. S. Kshetrimayum
123
LT ;t tð Þ ¼ 1ffiffiffip
pXNH
k¼1
wHk exp jt10
ffiffi2
prxHkþlT ;t
10
� ð18Þ
where r ¼ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffir21 þ r21
pand lT ;t ¼ 10
lnð10Þ lnX0 � TC � t�T
cln 1010
� �2 r22
h i. The parameters fr1; r2g
and fC; cg are the standard deviations and the power decay factors for the cluster and ray,
respectively, are defined in Table 1. The PDF, fe0 xð Þ of e0 can be computed as
fe0 xð Þ ¼ 12p
R1�1 we0 tð Þ exp �jtxð Þdt. Note the X2 and e0 are statistically independent to each
other therefore, the PDF, f~e xð Þ of ~e can be computed as f~e xð Þ ¼R1�1
1yj j fX2 x
�y
� �fe0 yð Þdy.
Using the above results, the final characteristic function, w~e sð Þ expression of ~e is given as
w~e sð Þ ¼ 5ffiffiffiffiffiffiffi2p5
prx ln 10ð Þ
XNH
k1¼1
XNH
k2¼2
XNH
k3¼1
XNH
k4¼1
wHk1wHk2wHk3wHk4
y
x yj j
�
� exp jt10ffiffi2
przþl0;010 � k ~wt 0; Lð Þ � K~J t; Lð Þ � j ty� sxð Þ
�
� exp �10log10
xy
�
ffiffiffi2
prx
0@
1A
2
þ t2 þ y2 þ x2
0B@
1CA
�������x¼xH
k1;y¼xH
k2;t¼xH
k3;z¼xH
k4
9>>=
>>;
ð19Þ
3.3 ABER for the S–D Link
In this link, the single transmitting antenna is selected which maximized the SNR at the D
terminal. Suppose ith transmitting antenna account the maximum SNR and destination
performs the MRC scheme to combine all the received signals, then the received SNR at
the D terminal can be computed as
cSD ¼ p1
N0
CSDið Þ ð20Þ
where C ið Þ ¼ max1� i�NtCif g. Under the assumption of i.i.d. channel links, the distribution
of CSDi is equivalent to the distribution of the CSRi . Hence, the PDF, f SDCi ðxÞ of CSDi can be
calculated as in (11). However, the CDF, FSDCi ðxÞ can be calculated as
FSDCi xð Þ ¼ x
2
XNL
b¼1
wLbf
SDCi
x
2xLb þ 1� � �
ð21Þ
From the Eqs. (2), (10), (11) and (21), the PDF, f SDC ið ÞðxÞ of CSD
ið Þcan be computed as
f SDC ið ÞðxÞ ¼ Nt
2pð ÞNtGSDi x;Nrð Þ
� �Nt�1 XNH
k¼1
wHk
YNr
v¼1
wSDei;v xHk� �
" #e xH
kð Þ2�jxHkx
� � !ð22Þ
where wSDei;v xHk� �
is given in the Eq. (19) and the function
Glinki r1; r2ð Þ ¼ r1
2
PNL
b¼1
PNH
k¼1 wLbw
Hk
Qr2v¼1 w
linkei;v xHk� �h i
exp xHk� �2 � jxH
kr1
2xLb þ 1� � �h i
. Now
the ABER for the S-D link can be calculated as
Transmit Antenna Selection in the Cooperative Communication... 3007
123
pe SDð Þ cSDð Þ ¼ Nt
2pð ÞNt
XMl
q¼1
XNH
k¼1
wlqw
Hk
YNr
v¼1
wSDi;v xHk� �
!GSDi xlq;Nr
�h iNt�1
(:
� F p1;N0; xHk ; x
lq; qr
�)ð23Þ
3.4 ABER for the S–R–D Link
In this link, both the S and the R terminals transmit the information after executing the TAS
scheme, only when relay decodes the received information correctly. Under the assumption
of i.i.d. channel link, the received SNR in the S-R-D link is approximately equal to the sum
of the SNRs received in the S–D and R–D links, is given as
cSRD ¼ cSD þ cRD
¼ p1
N0
CSDðiÞ þp2
N0
CRDðiÞð24Þ
suppose p1 ¼ p2, then received SNR can be written as
cSRD ¼ cSDjNr¼2Nrð25Þ
Similarly, ABER for the S–R–D link can be computed as
pe SRDð Þ cSRDð Þ ¼ pe SDð Þ cSDð Þ��Nr¼2Nr
ð26Þ
Combining the Eqs. (7), (12), (23) and (26), the final ABER expression of the investigated
two-hop UWB system over IEEE 802.15.3a channel model is given as
�pe ¼Nt
2pð ÞNt
1
2p
XMl
q¼1
XNH
k¼1
wlqw
Hk
YNr
v¼1
wSRei;v xHk� �
!F p1;N0; x
Hk ; x
lq; qr
� !(
�XMl
q¼1
XNH
k¼1
wlqw
Hk
YNr
v¼1
wSDei;v xHk� �
!GSDi xlq;Nr
�h iNt�1
F p1;N0; xHk ; x
lq; qr
� !
þXMl
q¼1
XNH
k¼1
wlqw
Hk
Y2Nr
v¼1
wSDei;v xHk� �
!GSDi xlq; 2Nr
�h iNt�1
F p1;N0; xHk ; x
lq; qr
� !
� 1� 1
2p
XMl
q¼1
XNH
k¼1
wlqw
Hk
YNr
v¼1
wSRei;v xHk� �
!F p1;N0; x
Hk ; x
lq; qr
� !)
ð27Þ
4 Numerical Results
In this section, we present the simulated and analytical BERs of the investigated UWB
system over IEEE 802.15.3a channel model. For simulation and numerical analysis, we set
NH ¼ NL ¼ Ml ¼ 40, Tc ¼ 1 ns, qr ¼ 0, L = 10, number of bits =100000 and other
3008 A. Agrawal, R. S. Kshetrimayum
123
channel parameters are given in Table 1. The simulated and analytical BERs comparison
between the conventional (non-cooperative-SISO) and the 3; 1; 3ð Þ based investigated
UWB systems over IEEE 802.15.3a CM1 are shown in Fig. 2. It is observed that the
investigated UWB system has significantly improved the BER over the conventional one.
Figure 3 shows the effect of the number of antennas on the BER of the investigated
system. The results show that BER decreases with increase in the number of antennas in
1 2 3 4 5 6 7 8 9 1010−5
10−4
10−3
10−2
10−1
100
SNR (dB)
BER
Ana for the conventional systemSim for the conventional systemAna for the (3,1;3) investigated systemSim for the (3,1;3) investigated system
Fig. 2 Simulated and analytical BERs comparison between the conventional and investigated UWBsystems over IEEE 802.15.3a CM1
0 1 2 3 4 5 6 7 8
10−4
10−3
10−2
10−1
10 0
SNR (dB)
BER
Analytical BERSimulation BER
(2,1;2) TAS/MRC
(3,1;3) TAS/MRC
(4,1;4) TAS/MRC
Fig. 3 Effect of number of antennas on the BER of the investigated UWB system over CM1. whereNt ¼ Nr = 2, 3 and 4
Transmit Antenna Selection in the Cooperative Communication... 3009
123
the TAS/MRC scheme of the investigated system. This is because the diversity gain, we
achieved by employing the multiple antennas in the two-hop UWB system. Similarly, the
simulated and analytical BERs of the (3,1;3) based two-hop UWB system over IEEE
802.15.3a CM1 4 shown in Fig. 4. The results show that the analytical BER is a good
match to the simulation one.
0 1 2 3 4 5 6 7 8
10−4
10−3
10−2
10−1
100
BER
SNR (dB)
Sim for CM1Ana for CM1Sim for CM2Ana for CM2Sim for CM3Ana for CM3Sim for CM4Ana for CM4
Fig. 4 Simulated and analytical BERs of the (3,1;3) based two-hop UWB system over IEEE 802.15.3aCM1 4
0 1 2 3 4 5 6 7 8 9 10
10−4
10−3
10−2
10−1
SNR (dB)
BER
σX =3dB
σX =6dB
Conventional UWB System
(3,1;3) TAS/MRC Based Two−Hop UWB System
Fig. 5 Effect of shadow fading standard deviations rXindBð Þ on the BERs of the conventional and the(3,1;3) based two-hop UWB systems over CM1. where rX= 3 and 6 dB
3010 A. Agrawal, R. S. Kshetrimayum
123
Fig. 6 A flowchart of the Monte-Carlo simulation for the BER calculation of the investigated UWB system
Transmit Antenna Selection in the Cooperative Communication... 3011
123
Figure 5 shows the effect of shadowing standard deviations rX ¼ 3 dB&6 dBð Þ on the
BER of the conventional and the (3,1;3) based two-hop UWB system over CM1. It is
observed that BER at rX= 6 dB, is higher than the BER at the rX ¼ 3 dB for both the
UWB systems. It is inferred that shadow fading shows a significant effect on the BER.
Therefore, it can not be ignored while calculating the performance of UWB system over
IEEE 802.15.3a channel.
To understand the Monte-Carlo simulation, a flowchart of the BER calculation of the
investigated UWB system is shown in Fig. 6 while Fig. 7, shows a flowchart of the TAS
scheme, which is performed at the source and relay terminals.
Fig. 7 A flowchart of the Monte-Carlo simulation of the TASscheme
3012 A. Agrawal, R. S. Kshetrimayum
123
5 Conclusions
In this paper, we derived the ABER of the TAS/MRC based two-hop UWB system over
IEEE 802.15.3a channel models. The analysis considered the i.i.d. channel links and the
relay is configured to performed decode and forward cooperative strategy. Our results
show the simulated and analytical BERs comparison between the conventional and the
investigated UWB system. It is observed that the investigated UWB system has signifi-
cantly improved the BER over the conventional one. It is also noticed that the analytical
BER is well matched to the simulated one, which verify the accuracy of derived BER and
the approximations considered in the analysis. This paper presents the effect of the number
of antennas and the shadow fading deviations on the BER of the investigated UWB system.
To understand the Monte-Carlo simulation, the flowcharts of the ABER calculation of the
investigated UWB system and the TAS scheme are also presented.
References
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A. Agrawal received his M.Tech. degree in Digital CommunicationEngineering from National Institute of Technology (NIT) Bhopal,India, in 2010 and the B.E. degree in Electronics and CommunicationEngineering (ECE) from Samrat Ashok Technological Institute(SATI), Vidisha, India, in 2008. He is currently a Ph.D. Candidate inthe Department of Electronics and Electrical Engineering at IndianInstitute of Technology Guwahati, India. During September 2015 toJanuary 2016, he was an exchange student with National Tsing HuaUniversity, Taiwan where he worked on performance analysis ofMillimeter wave communication systems. His research interests are inthe areas of Cooperative communication, UWB wireless communica-tion systems, Millimeter Wave communication and MIMO.
R. S. Kshetrimayum (S’02, M’05, SM’14) received the BTech degreein EE from IIT Bombay in 2000 and the Ph.D. degree from the Schoolof EEE, NTU Singapore in 2005. Since 2005, he has been with thedepartment of EEE, IIT Guwahati as an Associate Professor (2010–),Assistant Professor (2006–2010) and Senior Lecturer (2005–2006). Heworked as a Postdoctoral Scholar at the department of EE, Pennsyl-vania State University (PSU) USA (2005), Research Associate Pro-visional at the department of ECE, IISc Bangalore (2004–2005) andTrainee Software Engineer at Mphasis Pune, India (2000–2001). Hehas been involved in organizing several IEEE international confer-ences in various capacities including Technical Program Chair (com-munications track) of NCC, Guwahati, India, 2016, Session co-chairon MIMO Signal Processing of DSP, Singapore, 2015, Technicalprogram co-chair of AEMC, Guwahati, India, 2015 and WOCN, Paris,France, 2011, Session chair on Microwaves II of NCC, Bangalore,India, 2011, Publication co-chair of CMC, Shenzhen, China, 2010 and
Program co-chair of NetCom, Chennai, India, 2009. He is the Editor-in-Chief of International Journal ofUltra Wideband Communications and Systems (Inderscience), 2009–, Editorial Board Member of Inter-national Journal of RF and Microwave Computer-Aided Engineering (Wiley), 2015–, Area editor of AEU
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International Journal of Electronics and Communications (Elsevier), 2016–, Associate editor of IET Journalof engineering, Editor of Transaction on Internet and Information system (Korean Society for InternetInformation) and referee of several IEEE journals. Dr. Kshetrimayum is the recipient of IETE Smt M.Rathore Memorial Award (2015), Dept. of Science and Technology India (SERC) Fast Track Scheme forYoung Scientists (2007–2010) and NTU Research Scholarship from 2001 to 2004. His current areas ofresearch interests are in microwave/millimeter wave antennas/circuits, UWB communications and MIMOwireless communications. He has published over 100 research papers in the areas of his research interests.Since 2014, he is a Fellow of the IETE, Optical Society of India and a Senior Member of IEEE, USA.
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