# Combined Channel Estimation with Interference Suppression in CPSS
## 5 Method Application  
As an important component in CPSS, data serve as a carrier system connecting cyberspace, physical world and artificial world. Depending on the communication network, data in both the physical and artificial world are transmitted to cyberspace, which are analyzed and calculated in the cyberspace. The analytic results and decision making then give feedback to the physical and artificial world through the communication network. Thus, the stability and reliability of the communication network is the prerequisite for efficient CPSS operation.  
When applied in telemedicine, based on various wearable device sensors, CPSS can continuously monitor physiological vital signs and transmit them for remote diagnosis. Interference in communication may cause distortion of data [29]. When proper data cannot be received by the control  
Figure 5: BER in different interference suppression schemes.  
Figure 6: BER in different interference styles.  
center in time, the quality of health monitoring is affected which may further lead to misdiagnosis and failure to provide timely treatment to the patients [30]. In CPSS-based intelligent transportation systems, the position of mobile phones and vehicles can be used to analyze the dynamic changes of traffic conditions, so as to carry out traffic flow control and traffic guidance. Similar applications require human beings, vehicles and roadsides to be connected via universal and ubiquitous networks enabled by wireless communications, such that they can act cooperatively. The coexistence and cooperation of the wireless communications give rise to interference coordination and resource allocation problems [31].  
Due to the diversity of communication systems in CPSS, frequency spectrum coordination is becoming increasingly difficult. That interference suppression provides an alternative option for anti-interference.  
We have applied the proposed scheme to an intelligent connected vehicle (ICV). As shown in Figure 7, the ICV established the connection with the cloud center through the public mobile communication network, such as 3 G, 4 G, 5 G, and established the connection with roadside and human through short-range communications such as RFID, bluetooth, and the connection with other vehicles via broadband self-organization networks (SON). Based on these communication systems, the resources on the clouds, roadsides and vehicles have been integrated seamlessly. By jointly considering the information from physical, social, and cyberspace, safety and optimal driving experience could be effectively realized.  
There are multiple wireless communication systems in such a small vehicle, and the wireless channel will be a complex electromagnetic environment of mixed radio signals. In our experimental ICV, RFID and SON happened to be in the same frequency spectrum (Figure 8). The mutual interference would appear when the two communication systems work simultaneously. In actual assessment, the loss rate of transmission in vehicle-to-vehicle reached 15% without interference suppression. After applying the proposed scheme in SON, which combined interference suppression in channel estimation, the loss rate of transmission in vehicle-to-vehicle showed no significant changes regardless of whether RFID is working concurrently or not.  
Figure 8: Spectrum division of the communication systems in ICV.  
Figure 7: Communication systems in ICV.