Analysis of CMMB signal for Passive Radar
Detection
Yang Xu
1
, Lin Sun
1
, Tianyun Wang
1,2
, Xinfei Lu
1
, Chang Chen
1
, Weidong Chen
1
1
Key Laboratory of Electromagnetic Space Information, Chinese Academy of Sciences
Department of EEIS, University of Science and Technology of China, Hefei, Anhui, P.R. China
2
China Satellite Maritime Tracking and Control Department, Jiangyin, 214431, China
Email: {xuyang1, sunlin, wangty, lxfei}@mail.ustc.edu.cn, {chench, wdchen}@ustc.edu.cn
Abstract—This paper studies the feasibility of using China
Mobile Multimedia Broadcasting (CMMB) signal for passive
radar detection. The research focuses on the analysis of CMMB
signal properties which include signal structure, spectrum
analysis, target resolution, ambiguity function and reduction of
side lobes. Since CMMB signal has wide bandwidth and high
power in its coverage area, it has great advantages in passive
radar application. Experimental results show the performance
and potential capability of CMMB based passive radar in target
detection.
IndexTerms—passive radar, CMMB signal, target detection,
ambiguity function.
I. INTRODUCTION
Passive radar which takes advantage of the readily available
non-cooperative sources as illuminators attracts more and more
attentions of the researchers. Because this kind of radar makes
use of already existing signals, for example Frequency
Modulation (FM) radio [1], Global System for Mobile
Communication (GSM) [2], Digital Audio Broadcasting (DAB)
[3], Global Navigation Satellite System (GNSS) [4], it has
many advantages over conventional radars including lower cost,
more difficult to be found and almost immune to active
jamming. The technology of China Mobile Multimedia
Broadcasting (CMMB) [5] is a multimedia broadcasting
standard of small-size portable equipments and it has been
widely used in mobile TV in China. The bandwidth of CMMB
signal is wide enough to guarantee its relatively high range
resolution and its low central frequency in P band makes it
have the ability to detect weak targets. Besides, the power of
CMMB signal in its coverage area is high. Resulting from
these advantages, CMMB signal appears to be a good choice
for passive radar application.
In order to achieve the feasibility of using CMMB signal
for passive radar detection, it’s necessary to analyze the
properties of CMMB signal. In [6], researches linking to the
frame structure and CMMB system are presented but it doesn’t
analyze the ambiguity function. Wan Xianrong et al has
studied the method of clutter rejection in cp-OFDM signal
based passive radar in [7]. A direct path wave purification
algorithm based on NLMS is proposed in [8], which can
attenuate the multipath interferences of the direct path wave.
However, there is no discussion about reduction of side lobes
in both [7] and [8]. In this paper, we have not only analyzed the
properties of CMMB signal, but also conducted field
experiments to show the performance and potential capability
of CMMB based passive radar in target detection.
This paper is organized as follows. The properties of
CMMB signal are presented in section II, including the signal
structure, spectrum analysis, target resolution, ambiguity
function analysis and reduction of side lobes. Section III gives
a brief introduction about the system architecture of the
CMMB based passive radar and the experimental results are
also shown in this part. Finally conclusions are drawn in
section IV.
II. CMMB
SIGNAL PROPERTIES ANALYSIS
A. CMMB Signal Overview
The frame structure of CMMB signal is shown in Fig. 1.
The duration time of one frame is 1 second, which is divided
into 40 time slots (from TS0 to TS39). Each time slot consists
of one beacon and 53 OFDM symbols. The beacon is
composed of one transmitter identification and two identical
synchronous signals.
TS0 TS1
symbol 1
TS39
beacon symbol 0 symbol 52
synchronous
signal
TX ID
synchronous
signal
1s
25ms
409.6us
36us 409.6us
Figure 1. Frame structure of CMMB signal
The physical bandwidth of CMMB system is either 2 MHz
or 8MHz. In this paper, we discuss the latter one. If the system
bandwidth is 8MHz, the number of sub-carriers in one OFDM
symbol is 4096, which includes 2610 data carriers, 384 scatter
pilots, 82 continual pilots and 1020 zero sub-carriers.
One symbol of CMMB signal is formulated as
The work in this paper is sup
orted by National Natural Science Foundatio
of China under Grant No. 61172155 and the Hi-Tech Research an
Development Program of China under Grant Project No. 2013AA122903.
2014 Sixth International Conference on Wireless Communications and Signal Processing (WCSP)
978-1-4799-7339-2/14/$31.00 ©2014 IEEE