IEEK Transactions on Smart Processing and Computing, vol. 2, no. 2, April 2013
67
IEEK Transactions on Smart Processing and Computing
Outage Probability of Device-to-Device MIMO Relay
Systems with Imperfect Channel Estimation
Liang wu Wei
1
and Shi Xiang Shao
2
1
School of Communication and Information Engineering, Nanjing University of Posts and Telecommunication / Nanjing,
210003 -P.R.China weiliangwu_njupt@163.com
2
Jiangsu Key Laboratory of Radio Communication, Nanjing University of Posts and Telecommunication / Nanjing,
210003-P.R.China shaosx@njupt.edu.cn
* Corresponding Author: Shi Xiang Shao
Received December 26, 2012; Revised March 14, 2013; Accepted April 25, 2013; Published April 30, 2013
Abstract: Under an imperfect channel estimation, a Device-to-Device (D2D) communication
framework based on MIMO relay technology is presented. The model consists of a D2D pair
equipped with M antennas and a relay equipped with N antennas as well as a cellular user equipped
with M antennas. The outage probability under different relaying protocols (i.e. AF and DF
protocol) with and without considering a direct link was derived. The actual and theoretical outage
probability of the five links under different antenna numbers was emulated. The number of user
antennas and channel estimation error was analyzed carefully to determine their impact on the
outage probability of a system. The simulation verified the theory analyses and the results showed
that MIMO relaying improves the D2D communication system performance.
Keywords: D2D, MIMO, Relay, Outage probability, Channel estimation error
1. Introduction
In recent years, with the continuous development of
mobile communications, there has been increasing demand
for a higher network capacity and transfer rate. On the
other hand, the very limited radio spectrum resources used
in mobile communications, and how to use the spectrum
resources efficiently will inevitably become a primary
issue. By cognitive radio technology, Monitoring the main
system and sensing the free spectrum is difficult to achieve
in a broadcasting system. The terminal on international the
direct communications technology (Device-to-Device,
D2D) provides a solution for overcoming this shortcoming.
D2D is a new technology in a communication system of
the LTE (Long Term Evolution) by multiplexing the
spectrum resources of the cell within the cellular user to
achieve Device-to-Device communication. D2D technology
is a close mobile end user under the control of a control
signal from the base station. The base station spectrum
resources are allocated to them so that the direct
transmission of data information of the two communi-
cation terminals and the data message does not need to be
forwarded. Therefore, it is possible to reduce the load of
the base station to increase the capacity of the system, and
increase the frequency of the system resource utilization
[1].
To improve the spectral efficiency of the system, the
D2D user and cellular users share the same system
spectrum resources, but at the same time brings the
problem of mutual interference. Interfering with D2D
communication results in cellular communication, whereas
the cellular communication can cause interference in D2D
communication [2]. This can increase the probability of a
system outage, an interruption of the performance, and
communication reliability degradation. Therefore, reducing
the outage probability of a D2D system is a major research
focus.
Multi-antenna MIMO technology [3, 4] can improve
the spectral efficiency and system capacity of a wireless
communication system. In a D2D system, it is possible to
improve the spectrum utilization and multiplexing gain. [5]
examined the D2D system outage probability, and reported
an approximate formula. Nevertheless, this paper only
discussed the case of a single antenna. [6] studied a D2D
user multiplexed with a cellular downlink spectrum and
reported that a multi-antenna MIMO technique reduces the
Preliminary results of this paper were presented at the IEEE VTC Fall
2013. This work is supported by National Natural Science Foundation of
China(61171093), The Major National Science and Technology Projects
of China (2012zx03003011-005).