As technology scales, increasing clock rates, decreasing interconnect pitch, and the introduction of low-k dielectrics have made self-heating of the global interconnects an important issue in VLSI design. In this paper, we study the self-heating of on-chip buses and show that the thermal impact due to self-heating of on-chip buses increases as technology scales, thus motivating the need of finding solutions to mitigate this effect. Based on the theoretical analysis, we propose an irredundant bus encoding scheme for on-chip buses to tackle the thermal issue. Simulation results show that our encoding scheme is very efficient to reduce the on-chip bus temperature rise over substrate temperature, with much less overhead compared to other low power encoding schemes.