Without doubt, the single most important property of any radio network is coverage. Since coverage engineering may be the most complex area of the radio system specification and design process, it is a critical area where your time investment will be well justified. While it may seem sensible and understandable to simply have a goal of coverage that is “the same as or better than the existing network,” statements like this are hard to quantify, and can lead to misunderstandings and difficulties in testing and proving success.
The Importance of Accurate Coverage Goals
Coverage goals that are ambiguous or unclear lead to ongoing frustration, project delays, and often unnecessary expense for both the customer and vendor. It’s critical to define coverage goals accurately so that system engineers can design, test, and verify that the new network is exactly what is wanted and needed. Properly-defined coverage goals sow the seeds for a successful project.
A properly-defined coverage goal must be:
- –able to be designed against (so both parties know when the design meets the goal)
- –testable and repeatable (so coverage can be tested against the goal once the network is built)
- –unambiguous (so it is clear to both the vendor and customer when the goal has been met)
Three Steps to Successful Coverage Goals
For coverage engineers to effectively and efficiently design a radio system, the coverage goals must include answers to three critical questions:
1. What is the minimum acceptable quality of service?
You can define this as one (or more) of the following, which together describe what a user can reasonably expect:
- Received Signal Strength (RSSI) can be used for analog or digital, voice or data radio systems.
- Delivered Audio Quality (DAQ) can be used for analog or digital radio systems – usually for voice communications.
- Bit Error Rate (BER) can be used for digital voice or data communications.
- Message Error Rate (MER) can only be used for digital radio systems – usually for data communications.
2. How much area reliability?
This is the average reliability of communication within the service area.
- If service (or covered) area reliability is 95%, a user anywhere within that area has a 95% chance that they will have the minimum or better acceptable level of service.
- Reliability is usually 90% for Utilities and 95% for Public Safety systems.
3. Where must this occur?
This can be defined as either:
- Covered area – the area within which communication is predicted to meet or exceed the minimum criteria, or
- Service area – the area within which coverage has to meet or exceed the minimum criteria.
This free guide offers a best practice look at how to refine your answers to these questions to give you and your chosen vendor the best possible chance of completing a successful project. You’ll also find examples of properly worded coverage goals, reasons and examples of why poorly worded goals won’t work, and other important information to consider.
For a further look into the process of designing a radio network with optimal coverage, download our white paper: Specifying, predicting and testing – three steps to coverage confidence on your digital radio network.