For this project, we will conduct the integration testing in three main phases using a primarily bottom-up integration strategy aligned with the layered architecture of networking, communication control, and user interface. The first phase focuses on integrating the core communication control logic and the networking abstractions that support WiFi, LTE, 5G, and the legacy trunked radio network. The second phase extends the integrated core by adding multi radio coordination capabilities and the components that manage repeater towers, gateways, and failover behavior. The third phase completes the integration by adding the user facing interfaces and administrative tools, resulting in a build that represents the full Communications Control Software with WiFi, LTE, and 5G capabilities.
In the first phase, the partial build will contain the control channel manager, the network selection and handover logic, the session and talk group management services, and the basic networking interfaces that abstract the different underlying transport technologies. At this point, there is no graphical user interface or full operator console, and any physical radio hardware or external systems not yet integrated will be simulated with simple drivers and stubs. This phase allows us to test core behaviors such as establishing Push to Talk sessions, selecting an available network path, maintaining state across sessions, recording basic call metadata, and handling error conditions on a single or small number of radios. Because these services are responsible for satisfying requirements like automatic network switching, connection success rate, and basic latency constraints, exercising them early in isolation from higher layers makes it easier to identify design or protocol issues before they are obscured by user interface concerns.
In the second phase, the partial build will extend the core communication control services with the modules that manage interoperability gateways and repeater towers, as well as the logic for coordinating multiple radios and communication paths. This includes the components that interact with the LTE and WiFi gateways, the tower control and monitoring services, the priority and emergency routing logic, and the backup path selection and recovery mechanisms. The intention in this phase is to test scenarios where many radios and users share a pool of frequencies and broadband links, where traffic must be routed across different networks, and where failures or degraded links trigger automatic switchover to backup paths. By integrating gateways and tower control at this stage, we can evaluate capacity related requirements, such as the number of simultaneous connections and end to end delay under load, in an environment that is still simpler than the full user-facing system but already reflects realistic multi network behavior.
In the third phase, the build will include the complete user interface and operator consoles for both front line personnel and system administrators. This final integration step connects the communication control and networking layers to the user interface layer that implements Push to Talk buttons, emergency alert operations, talk group configuration screens, status dashboards for towers and gateways, and historical call record views. This phase allows us to verify that user actions are correctly translated into control requests, that feedback on system state and network selection is presented accurately, and that user workflows for common scenarios such as creating talk groups, responding to emergencies, and monitoring remote sites behave as intended. Because the underlying control and networking functionality has been exercised in the earlier phases, the focus here is on validating end to end behavior, usability-oriented flows, cross-platform consistency, and the correct propagation of failures and recovery events up to the user level.
A bottom-up integration strategy is appropriate for this system because the most complex and risk-prone behavior occurs in the lower layers that manage multiple heterogeneous networks, coordinate repeater towers, and maintain reliable sessions under failure conditions. Integrating and testing these layers first reduces the number of stubs required and allows the team to address issues in network selection algorithms, control channel handling, and failover logic before introducing user interface variability. Alternative strategies, such as starting with the user interface and stubbing out all communication services, would require extensive and fragile stubs to mimic detailed timing and failure scenarios on WiFi, LTE, and 5G paths. By instead building upward from the communication core, each subsequent phase reuses tested functionality and adds a thin layer of new behavior, which simplifies defect isolation and yields a clearer understanding of how the architecture supports the project's functional and nonfunctional requirements.