Position location using wireless communications on highways of the future

Abstract

With recent advances in wireless communications and low-power electronics, accurate position location may now be accomplished by a number of techniques which involve commercial wireless services. Emerging position location systems, when used in conjunction with mobile communications services, will lead to enhanced public safety and revolutionary products and services. The fundamental technical challenges and business motivations behind wireless position location systems are described in this article, and promising techniques for solving the practical position location problem are treated.

Massive MIMO Technologies and Challenges towards 5G

“…For example, increasing the carrier frequency from 3 GHz to 30 GHz results in severe increase in path-loss, and a 10-fold increase in Doppler (for the same speed) [53]. As the same time the channel becomes a lot sparser (i.e., it has a lot fewer dominant multipath components).…”

“…By assuming a user-channel coherence time of I OFDM symbols, each RB comprises N = (L total /L)I time-frequency resource elements (REs) or channel uses, spanning a contiguous set of L tones and a contiguous set of I OFDM symbols. In particular, assuming a maximum (accommodated) mobile speed of v, I can be found as the largest integer for which user channel coherence time is given by [53] …”

A comparison between UWB and TDOA systems for smart space localization

“…For the AOA method, the mobile target's location is estimated by first measuring the angle of arrival of a signal transmitted by the target as shown in Figure 4. Estimation of the AOA, commonly referred to as direction finding, can be accomplished with a narrow beamwidth antenna or with an array of antennas [16]. The AOA localization method requires two nodes A and B, with known locations, and two measured angles to derive the location of the target P in two dimensions.…”

Joint angle and delay estimation using shift-invariance techniques

“…A commonly used multiray propagation model for specular multipath writes the impulse response as (2) where is a known pulse shape function by which is modulated. In this model, there are distinct propagation paths, each parameterized by a triple , where DOA; path delay; C complex path attenuation (fading).…”

“…In general, it can involve the joint estimation of frequencies, Doppler shifts, directions of arrival (azimuth/elevation) and time/time-difference of arrival, and as such, it is the central issue in many radar or sonar applications. In mobile communications, source localization by the base station is of interest for advanced handover schemes, emergency localization, and potentially many user services for which a GPS receiver is impractical (see [2] for a recent discussion in this area).…”