How to bridge the gap between LMR and wireless broadband
What is in this article?
Traditionally, program managers have the same responsibilities as project managers, but with additional responsibility for budgets, timelines and resource management — sometimes over multiple projects. The program manager's planning includes all project-management functions, as well as the dimensioning of crews and materials, so that project managers have the tools to do their jobs .
Starting in the design phase, program managers have an opportunity to influence future expansion by ensuring that all project attributes are sized for LMR and a broadband layer. Key design attributes are the radio network, site selection and licensing, permits and zoning, system architecture, backhaul, dispatch and network monitoring.
Antenna systems and link budgets are key components of the radio network. A typical LMR layer has higher RF power, balanced downlink and uplink paths, and tall radio-tower or rooftop sites that provide long-range coverage. Broadband systems typically have lower RF power, unbalancing in the link budget (depending on the type of subscribers and the spectrum plan), lower antenna heights, and shorter coverage range per site.
These differences in the radio networks require the program manager to allocate extra resources, if a broadband layer is added.
Because traditional LMR systems use fewer sites than broadband systems covering the same territory, planning for site selection, FCC/FAA licensing, permitting, zoning, architecture and backhaul will differ between the two.
For example, it is estimated that four or five broadband sites will be needed to provide the same coverage and quality of service provided by a single LMR site; so, the increase in hardware in a broadband system is substantial. Beyond the increase in radio base stations, broadband networks have increased complexity, because the routing of information takes multiple paths, and the need for redundancy magnifies the challenge.
Moreover, there is additional transmission of the primary backhaul paths in a broadband system due to the increase in bandwidth and data, as well as the possibility of transport of one site's data through another, depending on the architecture. This can impact planning budgets, timelines and resources.
As the project enters the preliminary-design phase, the differences between LMR and broadband systems are important to the program manager's planning. Additional sites, hardware and backhaul increase the project size, even if the consideration is simply future planning for a broadband layer.
During the preliminary-design review, the radio coverage, scheduling, budget, test plans, system architecture, site leasing or purchasing, and licensing are dimensioned for LMR, but there is an opportunity to consider a broadband layer. To do so, the schedule may be extended, or additional crews and resources could be considered. The coverage will be reviewed, and LMR and broadband estimates can be made.
Adding a broadband layer will affect test plans. Radio-coverage testing can be optimized, depending on the footprints, but site, system, functional and backhaul testing will be impacted. When the system architecture and backhaul are reviewed during the preliminary-design phase, the estimated impact of the broadband layer should be included, so that the program manager can plan for the dramatic increases in hardware and transmission paths.
The final-design review is when the program and project managers will evaluate available resources and determinescheduling. Materials delivery and storage, personnel hiring and training, and civil-engineering requirements are reviewed and discussed between the customer, vendor and consultant. Materials cannot all be delivered at the same time, so logistics must ensure that cash flow and delivery timing match the needs of the project crew.
When planning the delivery of materials, the broadband layer uses most of the same components. As a result, if there is anticipation for broadband to be funded and built on the same sites as the LMR layer, there can be economies of scale in buying, storing and staging both layers simultaneously. Of course, if the broadband layer is many years away, then the cost of storing the equipment and depreciation may negate the benefits.