Transmit Antenna Selection in the Cooperative ...the relay assisted two-hop ultra-wideband (UWB)...

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]

A. [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

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[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


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�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.


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


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


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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


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


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


123

Fig. 6 A flowchart of the Monte-Carlo simulation for the BER calculation of the investigated UWB system


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


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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.

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promise of high-speed, short-range wireless connectivity. Proceedings of the IEEE, 92(2), 295–311.4. Abou-Rjeily, C., Daniele, N., & Belfiore, J.-C. (2008). On the amplify-and-forward cooperative

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17. Chen, Z., Chi, Z., Li, Y., & Vucetic, B. (2009). Error performance of maximal-ratio combining withtransmit antenna selection in flat nakagami-m fading channels. IEEE Transactions on Wireless Com-munications, 8(1), 424–431.

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systems with source and relay transmit antenna selection. Electronics Letters, 51(6), 530–532.23. Papoulis, A., & Pillai, S. U. (2002). Probability, random variables, and stochastic processes. New

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channel by superseding lognormal shadowing by Mixture of Gamma distributions. AEU-InternationalJournal of Electronics and Communications, 69(12), 1795–1799.

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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