M Porretta

A novel single base station location technique for microcellular wireless networks: description and validation by a deterministic propagation model

Positioning algorithms in cellular networks has become increasingly important as a means of supporting emerging services that require a sufficiently precise estimation of the position of the mobile terminal (MT) associated with a given base station (BS). Currently, even the most sophisticated positioning algorithms require at least three BSs to achieve satisfactory precision. This paper presents a novel algorithm that makes use of a single-BS antenna array to locate MTs in cellular networks. A triangulation technique is utilized and supported by some minimal information about the environment in the BS neighborhood. This algorithm is shown to perform well when operating in a microcellular environment with perfect channel-parameter estimation. The effect of finite resolution of the input parameters is also investigated. The performance is analyzed for a universal mobile telecommunications system microcellular scenario through a three-dimensional deterministic channel model. Finally, the performance of the proposed positioning technique is compared to the well-known location method based on the time-of-arrival measurements at three different BSs.

Estimating position and velocity of mobile terminals in a microcellular network using an adaptive linear regression setup

Mobility tracking yields efficient network resource management and enables very useful additional services, provided that accurate online estimations of both the location and the velocity of a mobile user are performed. We present a novel method for tracing a mobile user by subsequently estimating his/her position through a single base station positioning (SBSP) method designed for microcellular and third generation (3G) wireless communications systems. Raw data about user position are then smoothed through a linear regression setup which adaptively varies its inertia on the basis of the previous observations. This results in a tracking method which is able to estimate both the location and the velocity of a user with high accuracy, as proven by numerical results obtained in different microcellular scenarios.

Validation of a novel radio location technique by a deterministic propagation model

A radio location system operates by measuring physical quantities related to radio signals traveling between a mobile terminal (MT) and a set of fixed base stations (BSs). In order to reduce the implementation complexity and the signalling overhead, the solution presented makes use of a single BS to locate unmodified MTs. The novel algorithm applies a triangulation technique supported by minimal information about the environment in the BS neighborhood. The proposed algorithm is compatible with the architecture of 3G cellular networks, as it relies on CDMA (code division multiple access) signalling and a BS array antenna for the estimation of the time delay and of the angle of arrival, respectively. Despite its modest implementation complexity, the proposed algorithm can predict the MT position with a fairly good accuracy, as demonstrated by numerical tests performed by resorting to a fully 3D deterministic propagation model developed at the University of Pisa.