Location Area Update Research Articles

Trajectory estimation based on mobile network operator data for cellular network simulations

In this paper, we present a framework for estimating trajectories of cellular networks users based on mobile network operator data. We use handover and location area update events of both speech and packet data users captured in the core network of the Austrian MNO A1 to estimate the subscribers’ mobility behavior. By utilizing publicly available data, i.e., environmental information, road infrastructure data, transmitter power ranges and antenna characteristics, our approach allows the estimation of subscriber trajectories for both urban and semi-rural environments with a good accordance to the actual trajectories. Additionally, we present a method to estimate a particular subscriber’s movement velocity, on the basis of mentioned data. Furthermore, we propose a methodology to estimate when a particular user started or ended a speech or packet data session during his journey, based on mobility-related network events. With this, our framework enables the creation of reproducible mobility situations for cellular network simulations at system level.

Distance-Based Location Management Utilizing Initial Position for Mobile Communication Networks

This paper aims at improving the distance-based location management scheme for mobile communication networks. In location management, a mobile terminal (MT) is tracked based on its location-update area (LA). The improvement is brought about by joint optimization of LA center and LA size. For LA center optimization (LCO), we determine the optimal center position of the LA given the initial position of the MT upon each location update. The investigation of optimal LA center has eluded research to date. Based on the popular continuous-time random walk (CTRW) mobility model, we propose an analytical framework that uses a diffusion equation to determine the optimal LA center that minimizes the total cost of location management, consisting of the location update cost and terminal paging cost. This framework allows us to easily model the non-Markovian movement of the MT and evaluate the impact of various measurable physical parameters (such as length of road section, angle between road sections, and road section crossing time) and LA center. In particular, we show that proper LA center can significantly reduce the total cost. For example, for the circular LA and low Poisson call-arrival rate, optimizing the LA center alone has the potential of reducing the cost by up to 37 percent. Joint optimization of the LA center and terminal paging scheme can reduce the cost even further. Simulations results match the theoretical analysis to a gap within 3 percent, indicating that our theoretical model is very accurate.

Passive Mobile Phone Dataset to Construct Origin-destination Matrix: Potentials and Limitations

Mobile phone operators produce enormous amounts of data. In this paper we present applications performed with a dataset (communication events + handover and Location Area Up-date) collected by the operator Orange from 31 March to 11 April 2009 for the whole Paris Region. Trips are deduced from the spatio-temporal trajectory of devices through a hypothesis of stationarity within a Location Area in order to define activities. Trips are then aggregated in an origin-destination matrix which is compared with traditional data (census data and household travel survey).

Location update cost of distance-based scheme for PCS networks with CTRW model

This letter concerns the optimization of the dynamic location-update area (LA) for the per-user distance-based scheme in personal communication service (PCS) networks. We have two main contributions: (1) under the general and popular one-dimensional (1-D) continuous-time random walk (CTRW) mobility model, we propose a novel framework to analyze the location update cost; (2) with this framework, we investigate the impact of call arrivals and the initial position of the mobile terminal (MT) on the position of the LA, which was neglected by previous work. Simulation shows that our theoretical model is very accurate.

Performance of Mobile Telecommunications Network With Overlapping Location Area Configuration

In a mobile telecommunications network, the location area (LA) of a mobile station (MS) is tracked by an LA update (LAU) mechanism. To reduce the LAU traffic caused by the ping-pong effect, the overlapping LA concept is introduced. In the overlapping LA configuration, an LA selection policy is required to select the new LA at an LAU when the MS enters a new cell covered by multiple LAs. This paper describes four LA selection policies and proposes an analytic model to study the performance of these LA selection policies. Our study provides guidelines to determine an appropriate degree of overlapping among the LAs.

Adaptive location update area design for wireless cellular networks under 2D Markov walk model

In wireless cellular networks, location management operation expends the limited wireless resources to keep track the location information of a mobile terminal. Various dynamic location update (LU) schemes have been proposed to improve the efficiency of location management. However, most of them only work for certain mobility patterns. In this paper, we propose a new scheme that the LU area is adaptively designed according to the mobility pattern and traffic parameters. The 2D Markov walk is used as the mobility model which describes a broad class of mobility patterns. A recursive algorithm is developed to compute the location management cost of a general LU area shape. Due to the high computational complexity of the adaptive LU area design problem, we use an iterative greedy heuristic algorithm to find an approximation solution of the problem efficiently. The effects of the mobility patterns and traffic parameters on the designed LU area shape are investigated. Experimental results show that the LU area designed by the heuristic algorithm can adaptively change according to the given mobility pattern and traffic parameters. Compared with some existing dynamic LU schemes, the proposed adaptive LU scheme is more flexible and efficient for location management.

Optimal periodic location area update for mobile telecommunications networks

A normal location area update (NLAU) and a periodic location area update (PLAU) schemes are adopted in 3GPP specifications for Universal Mobile Telecommunications System to detect presence of mobile stations. In this paper, we compare the NLAU scheme, the PNLAU (NLAU+PLAU) scheme, and a dynamic PNLAU scheme in terms of signaling and initial trunk setup cost. We analytically model cost functions of these schemes per checkpoint event. Optimality issues of the PNLAU have been studied, and optimal values are derived. The first optimality issue is to minimize the total cost of signaling and failure call setup. The second optimality issue is to minimize the signaling cost with an upper bound on failure call setup probability. Simulations are carried out to validate against analytical results.

Hierarchical provisioning for cellular networks

We propose a hierarchical provisioning methodology to balance the network load within each location and routing area, as well as minimize the location and routing area update signaling cost. The hierarchical provisioning methodology consists of four optimization planes for cellular coverage area: 1) cell-oriented intra-SGSN layer, which is optimized routing areas covering the intra-SGSN signaling cost, paging cost, and routing area load balancing; 2) routing area-oriented intra-mobile switching center (MSC) layer, which is optimized location areas covering the intra-MSC signaling cost and location area load balancing; 3) routing area-oriented inter-SGSN layer, which is optimized SGSN coverage areas covering the inter-SGSN signaling cost, RNC, and SGSN load balancing; and 4) location area-oriented inter-MSC layer, which is optimized MSC coverage areas covering the inter-MSC signaling cost and MSC load balancing. We apply the niched Pareto genetic algorithm (GA) to the provisioning problem, which optimizes multiple objectives by incorporating the concept of Pareto domination in its selection operator, and applying a niching pressure to spread its population out along the Pareto optimal tradeoff surface. We then propose a schema-based partially matching crossover using a tournament size, where the crossover pairs are chosen in two steps, first based on the class ranking and then schema ranking. The new offspring are modified using the RA-based for intra- and inter-SGSN layers.

Delayed group registration scheme in group location tracking

In the conventional group location tracking (GLT) scheme, a mobile station (MS) performs a group location registration immediately after getting on a transportation system (TS), which is, however, unnecessary if the MS gets off the TS without any location area (LA) update. A delayed group registration scheme is proposed in order to avoid unnecessary group registrations and the resulting group registration cancellations, which take a major proportion in the total signalling cost of the GLT scheme. The result shows that the proposed scheme significantly outperforms the GLT scheme from the aspect of total signalling cost.

Dynamic periodic location area update in mobile networks

In mobile communications networks, periodic location area update (PLAU) is utilized to detect the presence of a mobile station (MS). In the 3GPP Technical Specifications 23.012 and 24.008, a fixed PLAU scheme was proposed for the Universal Mobile Telecommunications System (UMTS), where the interval between two PLAUs is of fixed length. We observe that MS presence can also be detected through call activities and normal location area update (NLAU). Therefore, we propose a dynamic PLAU scheme where the PLAU interval is dynamically adjusted based on the call traffic and NLAU rate. An analytic model is developed to investigate the performance of dynamic and fixed PLAU schemes. This paper provides guidelines to select parameters for dynamic PLAU.