Overview of Methods to Predict Radio & Radar Coverage and Interference using WinProp & WRAP - Part 2
Altair EmployeeSimulating Radio & Radar Coverage and Evaluating Interference
This second part shows further cases how the radio & radar coverage can be predicted and the interference can be evaluated using Altair Feko with WinProp and WRAP technologies.
Case 4: 6G Reconfigurable Intelligent Surfaces and Non-Terrestrial Networks Including HAPS
Various new technologies and use cases will be supported in 6G. Reconfigurable intelligent surfaces (RIS) are a promising technique to provide a cost-effective and energy-efficient solution for various radio environments. This includes passive element arrays which control the incident waves and the main beam redirection through intrinsic phase tuning, by optimizing parameters for the precise angular coverage, which can be designed in Feko.
The effect when deploying the RIS element e.g. in an indoor scenario to fill-up coverage holes can be evaluated and demonstrated using WinProp as shown in the following picture. The ray tracing result showing the received power situation confirms that the designed RIS redirects the impinging signal towards the NLOS part of the building floor.
6G will also feature more and more Non-Terrestrial Networks (NTN) which provide a global coverage, also in remote areas outside the bigger cities in a very efficient way. The terrestrial coverage of the 5G networks is still limited outside the cities, especially in larger countries like the US or China. Here the offering by satellite networks will be further evolving and there are already various systems in place including Starlink, Kuiper and OneWeb. Especially to support mobile users e.g. driving by car over larger distances more and more satcom antennas will be integrated in vehicles and other devices. Therefore WinProp and WRAP have been further refined to predict the satellite radio coverage in the various areas of interest.
Also, ITU-R P.1409, which provides propagation predictions for systems using high-altitude platform stations (HAPS) or other elevated stations in the stratosphere, has been implemented in WRAP, as depicted in the figure. It can be used for broadband connectivity, in-flight internet and linking backhaul traffic, enabling Space-Air-Ground communication.
Case 5: Radio Network Planning for Indoor Scenarios and Built-up Environments
The performance of wireless communication systems depends in a fundamental way on the mobile radio channel. In contrast to wired channels that are stationary and easy to design, radio channels show a time-variant behavior which complicates their analysis. Inside buildings the transmission path between transmitter and receiver can vary from simple line-of-sight to one severely obstructed by walls and furniture. As a consequence predicting the propagation characteristics belongs to the most important tasks for the design and installation of indoor radio networks, ranging from pico & femto-cells of cellular systems (LTE, 5G, …) to wireless local area networks using the latest WiFi standards.
The scenarios of interest range from multi-floor office buildings considering hard and soft partitions with different materials and subdivisions like doors and windows, to larger objects like train stations, airport buildings, underground metro stations, factory halls and even football stadiums, some examples are shown in the pictures. For the scenario import WinProp offers a wide range of filters including various CAD formats like DXF, DWG, Blender, etc.
A nice example of the WinProp capabilities for the 5G radio network planning in indoor scenarios is shown in this customer story, where NVIDIA produced an optimal 5G network design 10 times faster than traditional design and testing methods for their new headquarter in San Francisco.
Case 6: WRAP Applications in Defense – Maritime – Civil Aviation
Defense
Possible WRAP applications include the defense and mission planning because WRAP provides the essential tools to meet the frequency and radio network planning requirements for defense forces, regardless of the challenging conditions they face; these include difficult terrain, advanced warfare systems (AWS), radio jamming, and/or eavesdropping.
Supporting central, regional, and command units with strategic spectrum management, new system design and procurement, and frequency management in line with national and international allocations, WRAP users can strategize their tactical planning for short-term and long-term spectrum management with a focus on successful radio communications, electronic warfare, and radar coverage. The picture shows the radar coverage for a coastal area including the impact of wind turbines.
Full coverage for radio communication, navigation systems and surveillance radars is essential to ensure safety e.g. in busy coastal waters or in the more and more filled airspace. WRAP is a comprehensive system, ideally suited for the maritime and aviation applications.
Maritime
Finding good locations for radars and coastal radio stations to achieve good coverage of territorial waters and economic zones is a simple task with WRAP. Making use of detailed geographical data and advanced radio wave propagation models ensures high accuracy and quickly identifies blind spots that may need complementary coverage. WRAP can also investigate the impact of jammers and clutter on radar operation, while its coverage optimizer can be used for optimal placement of radars or jammers.
Radar coverage for different RCS targets (1-100sqm) without (left) & with (right) jammer
Civil Aviation
Constantly increasing air traffic means a corresponding increasing load on the air traffic control systems. Lack of frequency spectrum, full coverage for radio communication, navigation and surveillance of the airspace are factors that need serious consideration. Coverage for radio communication in air traffic control systems, frequency assignment to give lowest interference, best frequency utilization and required airspace radar coverage can be analyzed with WRAP. The efficient tools of WRAP give a cost-effective network design.
Case 7: Evaluating Co-Site Interference to Improve System Performance
Often multiple transmitting and receiving antennas are mounted on the same device, system or platform, including moving (like aircraft, ship or vehicles) and stationary (for example, towers or masts) ones. The antennas will mostly be designed for and connected with transmitters and receivers for different applications and frequencies. Yet, due to their proximity, there is a probability of interference (typically called co-site interference), mainly due to:
- Coupling between the antennas
- Non-linear electronic effects
Altair Feko not only enables antenna design, placement and coupling but also allows the user to analyze and mitigate interference in such scenarios, with the co-site/collocation interference tool using WRAP technology. Multiple antennas placed on a platform (e.g. aircraft, vehicle or ship), simulated and optimized in Altair Feko, can be analyzed for mutual interference in WRAP.
The Collocation Interference tool inside WRAP is used for multiple users, multiple service sites where several independent radio networks meet under severe, and high-level interference conditions. Output data is useful to provide guidance on changes in frequency assignments and changes in site configuration of the antennas.In addition to co- and adjacent- channel interference calculations, the collocation interference tool inside WRAP can consider Inter-modulation, Harmonics, Receiver Blocking, IF breakthrough and Image frequencies, using relevant equipment properties and coupling between the relevant antennas as inputs. The coupling depends on the values inside the coupling loss matrix, which defines the system losses between stations/terminals. WRAP can calculate these values automatically, based on how the Tx/Rx are defined inside the WRAP project. Further details and an aircraft example for co-site interference are given in this article.