Investigation of the human motion effects on 60 GHz indoor
office propagation
①
Zhao Junhui(赵 军辉)
②
*,**,***
,Liu Xu
*
(*School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing 100044, China)
(**State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong University, Beijing 100044, China)
(***National Mobile Communication Research Lab, Southeast University, Nanjing 210096, China)
Abstract
A modified random walk model for human motion is proposed to investigate the characteristics of 60 GHz
indoor office propagation. Compared with the classic random walk model, the movement tendency in the walking
process is taken into account in the modified model. Based on the proposed model, the path gains of the propagation
environment are simulated under a variety of different settings by using the ray tracing method. Simulation results and
analysis show that the human motion is a major source of disturbance to the indoor office propagation and results in
performance degradation in some areas.
Keywords: 60 GHz, human motion, indoor propagation, modified random walk model, ray tracing
0 Introduction
Due to the rapid development of consumer
electronic devices, such as smartphones, tablet
computers, and HDTVs, the demand for a short-range
and high-rate indoor wireless communication system is
becoming more and more urgent
[1]
. Especially, networks
that utilize millimeter-wave bands, typically 60 GHz,
have attracted lots of attentions for indoor wireless
applications. The bandwidth of several gigahertzes
around 60 GHz will be very beneficial to the design and
implementation of the future advanced indoor wireless
communication systems. Furthermore, the spectrum
around 60 GHz is license-free in many countries. In a
word, 60 GHz millimeter-wave radio technology is one
of the most prospective communication technologies in
the future 10 years.
There are mainly two approaches to get insight into
the characteristics of wireless propagation in an indoor
environment: measurement and simulation. Many
researchers have reported measurement results around
60 GHz in an indoor environment to assist the channel
modeling
[2-3]
. However, the cost of channel
measurement is extremely high and the collected data
have very limited expansibility for general use. On the
other hand, simulation techniques are free from the
limitations of experiments. In principle, all details of the
propagation can be obtained by solving the Maxwell
’
s
equations with boundary conditions that make
allowance for the physical properties of the walls and
objects within the environment. But it needs
sophisticated computational resources to carry out
simulations and overspends too much time. Therefore,
the ray tracing method based on geometrical optics is
proposed for propagation predictions.
So far, a lot of efforts have been done concerning
the ray tracing simulations in the 60 GHz band. Ref. [4]
examined the millimeter-wave propagation in a
conference room and proved the validation of ray
tracing results. Ref. [5] addressed the 60 GHz
propagation characteristics in an indoor office
environment by using the ray tracing software of
Wireless InSite. However, only little work has been
done concerning the human motion effects and even the
done work did not take account of the movement
tendency or the furniture in the propagation environment,
i.e., they assumed an empty room with random moving
human bodies
[4-5]
. In this paper, we will explore the
influences of human motion to the propagation in a
relatively more realistic indoor office room based on the
proposed modified random walk model and the
conventional ray tracing algorithm.
① Supported by the National Natural Science Foundation of China (61172073), Program for New Century Excellent Talents of
the Ministry of Education (NCET-12-0766), the open research fund of National Mobile Communications Research Laboratory,
Southeast University (2012D19), and the Fundamental Research Funds for the Central Universities (2013JBZ001)
② To whom correspondence should be addressed. E-mail: junhuizhao@bjtu.edu.cn