# Call Model and Test-Verification Methods for PS-LTE Core Equipment
## 4 Measurement of Wireless Coverage and Quality
### Measurement of End-to-End Call Services  
The measurement of end-to-end call services aims to confirm that smooth services are always provided for the areas where DSCNs have been established. For the end-to-end verification procedure, the measurement of voice, data, and video should be conducted for each service within a single base station, among multiple base stations, within heterogeneous network base stations, and between DSCN base stations and heterogeneous network base stations. For the measurement area, various types of verification areas and routes are selected for measuring end-to-end call services on the heterogeneous base stations (Samsung and Nokia) and heterogeneous networks (commercial, railway, and maritime networks). Moreover, the five major morphologies of national infrastructure, roads, densely populated areas, mountainous areas, and agricultural and fishery areas should be included by dividing downtown and suburban areas. For the measurement items, voice, data, and videos are measured for the following five types of call services according to call types.  
* For interception, only voice and data are measured, excluding voice transmission delay, voice quality, and data call connection measurement, while command devices and measuring instruments are not connected.
* For individual calls, voice/data call connection time, call time, voice quality, data transmission time, and video quality are measured.
* For group calls, voice/data call connection time, call time, voice transmission delay, voice quality, and data transmission time are measured, and the quality of group video is evaluated using the recorded video in the terminals.
* For multiple call group receptions, call connection time and call time are measured, excluding delivery delay time and voice quality, because measuring instruments cannot confirm whether the terminal has succeeded in moving from call group A to B.
* For multiuser full-duplex calls, call connection time and call time are measured, excluding voice quality, because measuring instruments cannot measure voice quality received in a mixed state of voices transmitted from several different terminals.  
The vehicle environment of the terminal and measuring instrument for measuring end-to-end call services are shown in Figure 10.  
Analysis of the measurement results of five end-to-end call services is as follows.  
* The success rate of text transmission is measured at 100%, and also measured are the completion rate of individual calls (voice--97%; video--97%), and the completion rate of group calls (voice--96%; video--99%).
* Because the communication environment between a tunnel section (commercial networks) and a ground section (disaster networks) changes frequently, the policy of RAN sharing with commercial networks should be clearly defined.
* As the radio resource control (RRC) connection release time is different for each business area, consultation among business operators is required; if no traffic is  
Figure 10: Measuring environment for end-to-end call services.  
present in area A for 10 s, it transitions to the RRC_IDLE state due to the occurrence of RRC connection release.
* Strengthening the examination of areas where DSCN services are weak is necessary, including the boundary area between disaster and commercial networks in mountainous areas, the boundary area between business operators, and the boundary area between regions (numerous call drops and network connection failures occur due to RAN-sharing failures).