An optimal ray tracing model for wireless indoor communication systems

Image based or non-image based ray tracing algorithms are generally used to characterize indoor propagation channels, However, the existing models can not efficiently cope with multiple reflected and/or transmitted ray fields, The optimal ray tracing model presented in this paper provides definite ad vantages in calculating the contributions of these rays, The proposed model is based on images, but it is optimum in the sense that only those rays wh ich belong to the configuration space and hence contribute to the received signal are automatically singled out at the outset. Mathematical formulatio ns of the optimal ray model are derived by the use of suitably defined auxi liary canonical problems. Then utilizing the asymptotic reduction of the co rresponding Green's function representations, explicit expressions are deri ved, which for given transmitter/receiver locations allow one to determine all possible ray paths and the associated field constituents. Due to the im proved computational efficiency, multiple reflected and/or transmitted ray fields can conveniently be traced in vector form. Signal fading and rms del ay spread characteristics of idealized indoor propagation environments can be calculated accurately. The optimal ray model presented in this paper can therefore be used to generate benchmark solutions for assessing the loss o f accuracy when depolarization effects are neglected or when the ray series is truncated prematurely.