March 12, 2019
Integration of multiple technologies across indoor and outdoor networks has placed tremendous pressure on mobile operators to maintain high-quality service. This applies to both public and private networks, as consumers have great expectations when streaming or surfing the Web, while public safety professionals must have reliable communications in mission critical scenarios. In many of these applications, RF coverage must be verified for multiple channels across a very wide frequency range.
A good example is how various commercial cellular operators must verify reliable service and acceptable throughput rates of indoor distributed antenna systems (DAS) found in many public spaces, such as shopping malls, airports, or sport stadiums. In many cases, numerous channels on multiple frequencies are used. Ideally, field technicians would test all these frequencies in parallel to maximize efficiency. Another example would be verifying the interaction of outdoor-to-indoor coverage for TETRA-based, in-building coverage systems and the resulting interferences.
Remote Spectrum Monitoring is Effective Solution
To address these network issues and preserve high-quality coverage in all areas, public and private operators are relying on remote spectrum monitoring tools, such as the Anritsu MS27101A Remote Spectrum Monitor shown in figure 1. The reason is simple – an effective test system can efficiently facilitate the identification and removal of illegal or unlicensed interference signals. The key is to select a system that effectively tracks multiple frequencies while being simple for field technicians to use.
Monitoring spectrum on a continual basis allows management to identify problem signals as they occur in real time. With additional software, a remote spectrum monitoring solution can also serve as a signal analysis platform for communications systems, such as TETRA, including broadband measurements showing the incoming direction of a signal or as a SatCom monitoring platform.
Spectrum Monitoring – Need for Sweep Speed
For coverage mapping applications, it is important that the scanning speed be fast enough to capture all the desired channels while seamlessly following the movements of the field technician conducting the measurements. Outstanding sweep speeds – even for smaller resolution bandwidth (RBW) or video bandwidth (VBW) – are particularly important for narrowband communications standards, such as analog FM, P25, TETRA, DMR, and dPMR.
The need for fast sweep speed can be seen when evaluating the various technologies. For example, dPMR uses 6.25 kHz channels, P25 and DMR use 12.5 kHz channels, and TETRA channels are usually separated into 25 kHz blocks within a 5 MHz frequency segment. Therefore, the remote monitoring solution must enable field technicians to acquire channel power and signal quality data by simply walking through a building, arena, mall or other area of interest, as well as see colored breadcrumb trails that indicate the power level and walking path (figure 2). Another feature to look for is if the application can designate multiple frequency sets that are individually defined by center frequency, SPAN, RBW, and desired reference level.
Control Via Mobile Device
The remote spectrum monitor shown in figure 1 can be controlled by technicians in the field using an Android-based mobile device and dedicated NEON Signal Mapper Software. A connection between the remote spectrum monitor and Android device can be established using a conventional Wi-Fi router. A communication test to verify that the device and monitoring solution are “speaking” to each other can be done at the beginning of the project by opening a web browser and entering the IP address of the remote spectrum monitor.
Before measurements can be taken, the NEON tracking unit must be calibrated. Once the calibration is complete, the technician can begin conducting tests. The software allows the measurements to be made using the remote spectrum monitor and displayed on the Android device. When the measurements are completed, the data can be stored locally on the mobile phone or tablet or uploaded to the cloud. It is recommended that sensitive and/or confidential data be saved on the device for security purposes.
Outdoor Coverage Mapping Option
Anritsu offers a software platform that is compatible with its spectrum monitoring hardware to automate data collection and for GPS-enabled coverage mapping, when outdoor monitoring needs to be done. The software allows users to view live data, record data related to given limit lines, or to record GPS-assisted measurement results.
Once settings have been verified, the field technician can begin recording and travel the designated route. All data is saved on the laptop’s hard drive. Because the data is gathered continuously, measurements need to be stopped as soon as the project is completed.
Multi-frequency radio coverage mapping is necessary to maintain coverage in both indoor and outdoor environments. This post outlines a process and solution to achieve the goal and ensure public and private networks meet KPIs. To learn more, download a new application note entitled Radio Frequency Coverage Mapping with Anritsu’s Remote Spectrum Monitor MS27101A, Vision™ MX280001A Software, and TRX NEON® Signal Mapper MA8100A.
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