Radio Resource Management

Abstract

This chaper is concerned with issues relating to link quality evaluation and handoff in cellular systems. The chapter begins by discussing several different types of signal strength-based handoff algorithms. This is followed by a detailed treatment of temporal-spatial signal strength averaging. Guidelines are developed on the window length that is needed so that Ricean fading can be neglected in continuous- and discrete-time signal strength averaging. We then motivate the need for velocity adaptive handoff algorithms and present three different velocity estimators. The velocity estimators are compared in terms of their sensitivity to the Rice factor, non-isotropic scattering and additive white Gaussian noise (AWGN). Afterwards, the velocity estimators are incorporated into a velocity adaptive handoff algorithm. We then provide an analytical treatment of conventional signal strength-based hard handoff algorithms, and do the same for soft handoff algorithms. Finally, we discuss methods for carrier-to-interference plus noise ratio, C ∕ (I + N) measurements in TDMA cellular systems.