This paper investigates the impact of radio irregularity on communication performance in wireless sensor networks. Radio irregularity, characterized by non-isotropic path losses and heterogeneous sending powers, is a common phenomenon that affects the performance of both MAC and routing protocols. The authors conduct experiments using MICA2 motes to gather empirical data, which is then used to develop the Radio Irregularity Model (RIM). This model accounts for the non-isotropic, continuous variation, and heterogeneity of radio signals. The RIM is integrated into simulations to analyze the impact of radio irregularity on MAC and routing protocols. The results show that radio irregularity significantly impacts routing protocols, particularly location-based protocols like Geographic Forwarding (GF), while having a relatively smaller impact on MAC protocols. The paper proposes six solutions to mitigate the effects of radio irregularity, including Symmetric Geographic Forwarding (SGF) and Bounded Distance Forwarding (BDF). These solutions are evaluated through simulations and a running testbed, demonstrating significant improvements in communication performance.This paper investigates the impact of radio irregularity on communication performance in wireless sensor networks. Radio irregularity, characterized by non-isotropic path losses and heterogeneous sending powers, is a common phenomenon that affects the performance of both MAC and routing protocols. The authors conduct experiments using MICA2 motes to gather empirical data, which is then used to develop the Radio Irregularity Model (RIM). This model accounts for the non-isotropic, continuous variation, and heterogeneity of radio signals. The RIM is integrated into simulations to analyze the impact of radio irregularity on MAC and routing protocols. The results show that radio irregularity significantly impacts routing protocols, particularly location-based protocols like Geographic Forwarding (GF), while having a relatively smaller impact on MAC protocols. The paper proposes six solutions to mitigate the effects of radio irregularity, including Symmetric Geographic Forwarding (SGF) and Bounded Distance Forwarding (BDF). These solutions are evaluated through simulations and a running testbed, demonstrating significant improvements in communication performance.