Arda Deniz 040200932
EHB 307E Communications 1 HW2
This report will cover the articles “An Experimental Implementation of China Digital Radio (CDR)
Broadcasting in Hubei” written by Li Gao , Jun Liu, Yihang Huang , Member, IEEE, and Aidong Men and
“Cooperative spectrum sensing technique for identifying illegal FM broadcast radio stations using an
energy detector and a peaks detector” written by Luis Diaz ; Homero Ortega.
The first paper is about the design of an experimental China Digital Radio (CDR) network with four FMband channels and two FM-CDR transmitting stations which is located in Hubei, China. The paper
discusses the issues of coverage discontinuity and service quality in the areas of Wuhan city, Wu-Huang
Expressway and Huangshi city and provides an experimental yet intelligent solution. To fulfill the
coverage criteria and prevent interference with the FM analog signal that is currently broadcast on the
air, The solution proposes that the experimental network makes use of a solution which combines a
Common-Regional-Information Channel (CRIC) that carries system information and service data, with
numerous service channels for Broadcast and Data Services (BADS). An Electronic Service Guide (ESG)
built within the CRIC helps noticeably improve service quality, most prominently in overlapping regions
especially during mobile reception, by informing receivers about material available from nearby and
current stations. Receiving terminals can access the CRIC and the BADS channels independently by using
two RF tuners. The Moon Mountain transmitting station in Huangshi and the Guishan transmitting
station in Wuhan are the transmitting stations for the Hubei CDR experimental network. Different
frequencies are used for CDR system transmission, with certain frequencies assigned for CRIC and BADS.
Wu-Huang Expressway overlapping regions are addressed, and data services, digital audio service, ESG,
and program scheduling information are among the material broadcasted. With a "central + provincial"
methodology, the CRIC platform's two-level structure seeks to offer both auxiliary services like ESG and
control information as well as common services like audio broadcasting. For mobile terminals, this
design makes seamless handovers across overlapping areas possible. When it comes to field testing, the
results show that CDR's coverage is similar to analog FM. On the other hand, CDR has higher reception
quality than FM in regions with more coverage. On the other hand, the boundary effect of CDR may
result in scenarios where the terminal can effectively listen to CDR programs but finds it difficult to
identify FM programs in areas that have weak reception.
The second paper discusses the issue of non-licensed illegal FM radio broadcasts (secondary users)
which cause interference to licensed radio broadcasting services (primary users) and ways of detecting
illegal FM radio broadcasts. It presents solutions in order to determine primary and secondary users
exploiting the VHF band of 88-108 MHz via automatic spectrum sensing for radio broadcasting. There
are two possible approaches. The first approach makes use of an energy detector, a device frequently
seen in cognitive radio systems. This method evaluates the input wave's energy over a specific time
interval and compares it with a dynamic threshold that relies on the noise floor. The second approach
involves a peak detector which finds carrier frequency peaks by using the Continuous Wavelet
Transform (CWT) on the Welch periodogram. When it comes to the comparison of the two proposed
methods, the following can be said: The energy detector is effective on a considerably wide range of
signal levels thanks to its adaptability while the peak detector has greater sensitivity to low signal levels,
however as a downside of the peak detector is that classification performance and accuracy could be
compromised. The energy detector’s higher classification performance is due to its higher Area Under
the Curve (AUC) in the Receiver Operating Characteristics (ROC) analysis. The energy detector is also
much less complicated and easier to implement in comparison to the peak detector as the peak detector
involves the additional intricacies of the Continuous Wavelet Transform and peak filtering. It can also be
said that both methods show improved performance with cooperative sensing (CS) in comparison to
non-CS situations. To summarize, the energy detector approach is more successful than the other in
identifying unauthorized FM broadcast stations since it is simple to use, adaptable, and has better
classification performance as determined by ROC curve analysis. Although it is more sensitive to low
level signals, the peaks detector might need careful and complicated calibration and has a major tradeoff when it comes to classification accuracy.
Sources:
An Experimental Implementation of China Digital Radio (CDR) Broadcasting in Hubei
L. Gao, J. Liu, Y. Huang and A. Men, "An Experimental Implementation of China Digital Radio (CDR)
Broadcasting in Hubei," in IEEE Transactions on Broadcasting, vol. 68, no. 3, pp. 797-801, Sept. 2022, doi:
10.1109/TBC.2022.3185448.
Cooperative spectrum sensing technique for identifying illegal FM broadcast radio stations using an
energy detector and a peaks detector
L. Diaz and H. Ortega, "Cooperative spectrum sensing technique for identifying illegal FM broadcast
radio stations using an energy detector and a peaks detector," 2019 XXII Symposium on Image, Signal
Processing and Artificial Vision (STSIVA), Bucaramanga, Colombia, 2019, pp. 1-5, doi:
10.1109/STSIVA.2019.8730244.