On the narrow-band assumption for array signal processing

The deployment of antenna arrays has been suggested for mobile communications systems to overcome the problem of limited channel bandwidth. However, signal processing has to be carried out very precisely in order to obtain satisfying results. Existing algorithms are mostly based on the assumption of narrow-band signals. The deviation of this assumption induces an error and consequently deteriorates the system performance. In this paper we present an upper-bound for the resulting error which is shown to be best possible. Finally, simulations are carried out to verify the result.