Load Balancing C-V2X Mode-3 with Overlapping Cell Architecture and Smart Handover

Seamless sharing of cooperative awareness Messages (CAMs) are critical to vehicle safety in intelligent transportation systems. Especially in cellular vehicle-to-everything (C-V2X), where the vehicle's resource selection is random, without the prior knowledge of neighbor vehicle resource usage. Efficient resource selection of vehicles is necessary to minimize collisions. To address this, we optimized C-V2X mode-3 operations with i) multiple overlapping cells, each using its own set of orthogonal RF subchannels (3 to 4 per cell), allowing each eNodeB to serve up to 400 vehicles without interference, ii) a smart handover mechanism that glides vehicles between these overlap areas to minimize the need for re-registration at cell boundaries and reduce signaling overhead and CAM delivery delays, and iii) balanced subframe allocation to mitigate CAM delivery failures caused by half-duplex. The proposed framework was fully implemented within the NS-3 simulation environment and evaluated under dense metropolitan traffic conditions, where it consistently achieved CAM delivery ratios up to 99.4 %.