Handover Measurement in Mobile Cellular Networks: Analysis and Applications to LTE

Abstract

This paper deals with handover measurement in mobile cellular networks. The work is dedicated to network modeling and performance evaluation. The exposition focuses on neighbor cell scanning and addresses its key probabilistic events: (i) suitable handover target found, (ii) service failure, and (iii) scan withdrawal under the interference-limited condition in a multicell system. We derive their expressions and provide a generalized framework for the analysis of handover measurement failure and target cell quality by the best signal quality and minimum duration outage. Results applied to LTE have also shown its effectiveness.

Some Properties of Large Excursions of a Stationary Gaussian Process

“…In particular, some recent investigations in the communication and networking domain include [6], [7] where Blachman investigated the shape of excursions and peak values of a frequency-modulated signal, [8] where Morgan addressed the level crossings of a discrete-time process and showed its connection to Rice's fundamental results for a continuous-time process, and [9] where Ramos-Alarcon et al studied the level crossing duration distribution of a Nakagami fading process. Beside these theoretically oriented works, applications in [10]- [15] have confirmed clear interest of this theory in wireless communications.…”

“…Basically, a radio link failure occurs when the signal power falls below a threshold and stays below during some minimum duration. This is a critical problem of all radio communication systems, and have been analyzed using the asymptotic properties of large excursions of a stationary Gaussian process, e.g., [11], [15]. Recent mobile systems, such as 3GPP 3G and 4G systems, introduce some kind of preventive measure to ameliorate the above mentioned radio link failure problem by searching for a new base station when the signal power of the tagged base station stays below a threshold over a predefined time duration.…”

A Unified Stochastic Model of Handover Measurement in Mobile Networks

“…Therefore, it is more appropriate and also generic to incorporate a minimum duration when characterizing the event. A service failure during is thus defined by an excursion of the serving cell's signal quality falling below the minimum tolerable level with minimum-duration (7) where denotes the SINR received from the serving cell at time . Fig.…”

“…However, most prior arts were concentrated on the handover control problem and its decision algorithms; see, e.g., [5] and [6]. The handover measurement function has received much less attention [7], and most investigations and analysis are through simulations over some case studies or selected scenarios. It is difficult to design a few representative simulation scenes from which one can draw conclusion that is applicable universally to various system settings.…”

“…This paper establishes a complete stochastic model and mathematical characterization of the handover measurement with explicit formulation of the involved probabilistic events. It is a generalization of the study in [7], which only contains a basic setup of major handover events and is thus limited to continual handover measurement such as intrafrequency handover measurement in WCDMA systems [21]. Moreover, it investigates the influence of different factors on the handover measurement for network optimization.…”