Dynamic signal strength estimates for indoor wireless communications

Signal strength estimation for indoor wireless communications has attracted much attention lately due to its many applications in mobile networking including coverage analysis, localization, fast hand-off, and security audits. However, it is challenging due to the complexities of the indoor radio propagation characteristics exacerbated by users' mobility. Therefore, a common practice of the indoor wireless research is to manually construct a radio signal strength table mapping signal strength with known locations inside a building. Obviously, this is a tedious and time consuming task; also, the resulting signal strength table does not describe the dynamic property of the indoor radio propagation. The table is static. Thus the credibility of any further application is heavily affected. This paper proposes a novel and automated signal strength estimation method for the indoor wireless research. The method requires only a single signal strength measurement as reference, and the estimated signal strength table is comparable to the actual measurements in real time. With 6 days of continuous measurements and simulations, the results show that the proposed method dynamically estimates the signal strength for the deployed building, and the results achieve average estimation accuracy to within 3% of maximum signal strength. With the dynamic method, the paper shows how the signal strength could be gracefully applied to special tasks such as coverage analysis, and localization.