Never are radio systems more vital than when they save lives.
Emergency services across the world rely on ATDI to deliver the communications they need.
On land, sea or in the air ATDI helps deliver public safety networks.
ATDI has completed planning, modeling and consultancy work for emergency services wherever they operate. The company has worked with police forces, fire brigades and ambulance services on land, with coastguards in coastal waters, with marine agencies in the deep ocean and with aviation traffic controllers in the air. In each case, the company’s expertise has resulted in networks which are robust and provide the required coverage, ensuring essential personnel are connected no matter where they are needed.
One issue with TETRA network designs is the ability to determine the number and the location for sites required to achieve the target coverage. The role of the RF planner is to find the best candidates to provide service for users in each area.
ICS telecom EV features a ‘prospective planning’ function, which identifies the best locations for new sites for greenﬁeld and densiﬁcation scenarios. This function is based on coverage target assumptions. After users (subscribers) have been generated, they will be used to automatically add sites and the connection to their parent base stations using different constraints. The TETRA network design is then automatically performed, taking into consideration the required criterion based on coverage thresholds and traffic demand.
TETRA is based on TDMA signals with time division of channels. To provide service to as many terminals simultaneously, each sector will need to use several TRx. As a result, during the network planning phase it is necessary to optimize the physical parameters (azimuth, tilt, frequency channel) to improve the coverage and the quality of the network.
Once the preliminary coverage of the network has been performed, an automatic station parameters optimisation process can be carried out. Featured in ICS telecom EV, this can optimise individually or simultaneously: antenna patterns, antenna height, azimuth, tilt and power. From a traffic demand perspective, ICS telecom EV will assign to each station the number of TRx required for each sector. ICS telecom EV also features an automatic frequency planning function which allows the user to choose from a predefined list or band of frequencies, resulting in an optimised frequency plan being automatically assigned to the network, resulting in a reduction or removal of interfered areas.
LTE mobile broadband enables the emergency services to utilise live mobile video, situation aware dispatching and remote diagnostics. The Mission Critical Push to Talk (MCPTT) feature provides one-to-one and one-to-many voice communication services. Each public safety device sends traffic data to a dedicated mission critical push to talk server and the server then copies the traffic to all the recipients. Although the number of public safety users is significantly lower than regular subscribers in any commercial LTE network, the number of simultaneously active public safety users can be very high, especially in a relatively small area when a major incident occurs.
The ‘parenting LTE’ feature in ICS telecom EV is based on a population of public safety users, with specific profiles and traffic demands defined. It will solve the issue of network traffic congestion (or low traffic QoS performance) by checking the performance of each site, including hot spot areas. This function considers DL/UL coverage criterions, traffic assumptions and schedulers.
Any LTE-based public safety solution needs to support direct communication between public safety users in high density areas. Proximity services allows two devices to communicate directly – without data routing through the EUTRAN network. 3GPP standardises proximity services (ProSe) for this purpose. The range of proximity networks depends on the strength of the received signal and the radio conditions, such as interference.
The “cluster assignment” functionality in ICS telecom EV, creates connections between different public safety devices constrained in terms of the distance between two linked devices, the maximum number of devices per station and per cluster. The connections between two subscribers will be made if the power received is greater than the predefined threshold. Connections between Subscribers/Clusters and eNodeBs, can be performed with the help of “Cluster Parenting” function, limited to the maximum number of devices allowed. The prospective planning feature can also automatically add new cells to ensure connectivity for all devices that cannot be directly connected to any existing eNodeB.