How to successfully project engineer a radio system — Part 3

Designing your new radio system
By Susan Ronning, P.E.

Business Planning DiagramIn a nutshell, the definition of a successfully designed radio system is one that that allows a user to talk to who they need to, where they need to, and when they need to.

The design phase includes three major project stages:

1. Needs analysis
2. Technical assessment
3. Preliminary design

1. Needs analysis
The needs analysis evaluates how and where the system is used today, what features and functions are working or not, and what is desired. It includes the following components:

•    Operability
•    Interoperability
•    Features and functionality
•    Maintenance and life-cycle support

Operability identifies the different types of radio users, where they need to communicate, and who, when, and how they need to communicate with inside the organization. It also ascertains the current operations and desired future operations.

Interoperability identifies the communications requirements with agencies outside of the organization. These may be neighboring municipalities, fire or utility districts, or the Red Cross, for example.

Features and functionality addresses the various system capabilities that users need or desire. Functionality may include emergency key-press to a specific talk-group, group calls which include multiple disciplines, talk-groups capable of roaming over adjacent agency systems, short data messaging, Advanced Vehicle Location, and over-the-air re-keying, among other requirements.

Maintenance and life-cycle support identifies how the agency manages to repair and maintain the radio system. Some agencies are self-maintained; they have a team of full-time radio and network technicians. Other agencies outsource their technical maintenance activities, but keep a system manager on payroll to manage the mobile and portable radio fleets.

2. Technical assessment
The technical assessment evaluates the radio system, its components, and the sub-systems in use against potential replacement equipment, spectrum, and technologies. It includes the following components:

•    Inventory of existing equipment
•    Coverage
•    Capacity
•    Spectrum
•    Technology
•    Backhaul connectivity
•    Network capacity
•    Redundancy

An inventory of existing subscriber equipment helps determine the amount of replacement mobile and portable radios needed. An infrastructure equipment inventory helps to identify the current coverage, capacity, spectrum and technology in use, and aids in categorizing the amount and types of sub-systems included with the radio network.

A coverage assessment models the reliability of a radio system’s area of two-way radio coverage.

A capacity assessment is akin to traffic modeling; it evaluates the number of users against the number of radio talk-paths through modeling tools.

Spectrum assessment includes the evaluation of current FCC licenses against proposed replacement system options. FCC licenses may need to be modified when moving from an analog to a digital system or from a conventional to a trunked architecture.

Technology assessment evaluates conventional and/or trunked system architectures and modulation schemes against user needs. Modulations include open standards like P25 or DMR, or proprietary technologies like SmartZone™ and EDACS™.

Backhaul connectivity refers to transport network. It is the microwave links, copper telephone or fiber lines between the radio sites and control points.

Network capacity, or bandwidth, refers to the amount of information that runs across the backhaul equipment. The radio system — along with other subsystems like alarm monitoring and site access-control systems — affects bandwidth requirements across the backhaul network.

Redundancy refers to a level of reliability in the radio system where there is no single point that can cause catastrophic failure.

3. Preliminary design
The findings from the needs analysis and technical assessment are analyzed against project goals and estimated costs in order to develop a preliminary design solution. It clearly lays out the system parameters and functionality.

Once the design phase completes, the project schedule and critical issues/milestones can be developed.

It’s important to understand that the design is preliminary at this point. A preliminary design provides a level playing field for vendors to bid on equipment and services. The final system design must be developed by the radio system vendor or system integrator if coverage, capacity, and other system guarantees are desired.

Look out for part 4 of this blog series next month: The project planning process

Susan Ronning, P.E., has experience as a vendor, consultant and customer, and has been involved in all aspects and phases of a project, from inception to final acceptance. She holds a BSEE and MBA and is an active member of the IEEE, APCO, and the Civil Air Patrol. Ms. Ronning is a Senior Systems Engineer for Tait Communications.


  1. […] Previous posts in this series: Part 1 – Overview Part 2 – The who, what, where? phase — getting your new radio system approved Part 3 – Designing your new radio system […]

  2. Tom Rochford says:

    Great overview Susan.

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