Performance analysis of two-user cooperative ARQ protocol over Rayleigh fading channel
Hailin Xiao
0
Ju Ni
1
0
School of Information and Communication, Guilin University of Electronic Technology
,
Guilin 541004, Guangxi
,
China
1
Library of Guilin University of Electronic Technology
,
Guilin 541004, Guangxi
,
China
In this paper, we present a two-user cooperative automatic repeat request (C-ARQ) protocol which combines cooperative diversity at the physical layer and ARQ at the link layer. In this scheme, distributed Alamouti space-time block coding (DASTBC) is applied to achieve cooperative diversity, and ARQ is used to improve the data link layer reliability. To analyze the performance of the proposed protocol, we derive the average frame error rate (FER) and throughput with multiple phase shift keying (MPSK) over a Rayleigh fading channel. Numerical simulation results show that the performance gain of average FER with ARQ retransmission is about 2 dB more than the case without ARQ retransmission in the same conditions. Moreover, the combined DASTBC and quadrature phase shift keying (QPSK) with ARQ retransmission will lead to an approximate 3 Mbits/s increase in transmission rate.
1 Introduction
Multiple antennas are often used to combat channel
fading in wireless communication system [1]. However,
implementing multiple antennas at a mobile station is
impractical for most wireless applications due to the
limited size of the mobile unit [2,3]. Relay-assisted
communication is suitable to solve the problem and
plays a main role in the future generation cellular
systems and ad hoc networks [4]. One form of
relayassisted communication is cooperative diversity [5,6].
Its principle is to exploit the broadcast nature of
wireless transmission and creates a virtual antenna array
through cooperating users. Each transmitting node has
its own message and is responsible for transmitting the
information of its partner(s). Therefore, a virtual
antenna array is obtained through the use of the relay's
antennas without complicated signal design or adding
more antennas into the nodes. In [7], a cooperative
diversity scheme between users has been used not only
to obtain higher throughput but also to decrease
timevarying channel sensitivity. In [8], multiple-source
cooperative message has been sent to a common destination,
and it is shown to offer full spatial diversity with better
bandwidth efficiency. In [9], differential relay strategies
over downlink channel in a two-user cooperative
communication system have been proposed, which are able
to achieve performance gain in association with the
proposed criterion. Recently, various techniques such
as distributed space-time coding [10,11] and
modulation [12] have been developed to realize cooperative
diversity. For achieving a diversity gain, the Alamouti
space-time block code (STBC) has been used in
cooperative system in a distributed manner [13]. These
cooperative diversity schemes have been shown to be able
to achieve significant performance gains over the
amplifyand-forward and decode-and-forward protocols [14].
Automatic repeat request (ARQ) protocol is
commonly used in the communication system to improve
the reliability, which requests retransmissions for those
packets received in error [15]. Recently, the ARQ
protocol has been applied in cooperative diversity system to
achieve higher link reliability; it is called cooperative
ARQ [16]. Cooperative ARQ (C-ARQ) protocol permits
nodes other than the source and the destination to actively
help deliver the correct data [3,17,18]. In [3], the authors
have analyzed the diversity multiplexing trade-off (DMT)
for ARQ-based opportunistic cooperative communication
over Nakagami fading channels. In [17], the authors have
designed the ARQ protocol for two-user cooperative
diversity systems in wireless networks. In [18], a cross-layer
Figure 1 Two-user cooperative diversity system.
C-ARQ has been studied, and the performance of spectral
efficiency over Nakagami fading channel has been
evaluated. In [19], a coordinated hybrid automatic repeat
request (HARQ) approach has been proposed, which can
improve the network outage probability and the users'
fairness. Despite that these studies are not relevant to
the average frame error rate (FER) and throughput of
cooperative ARQ, they can serve as references [20].
In this paper, we present a two-user C-ARQ protocol
which combines cooperative diversity at the physical layer
and ARQ at the link layer. To analyze the performance of
the protocol, we derive the average FER and throughput
Figure 2 Two-user cooperative ARQ protocol based on [15].
with multiple phase shift keying (MPSK) over a Rayleigh
fading channel. Numerical simulation results show that
the performance gain of average FER with ARQ
retransmission is about 2 dB more than the case without ARQ
retransmission in the same conditions. Moreover, the combined
distributed Alamouti space-time block coding (DASTBC)
and quadrature phase shift keying (QPSK) with ARQ
retransmission will lead to an approximately 3 Mbits/s
incr (...truncated)