W ireless location refers to the geographic coordinates of a mobile subscriber in cellular or wireless local area network (WLAN) environments. Wireless location finding has emerged as an essential public safety feature of cellular systems in response to an order issued by the Federal Communications Commission (FCC) in 1996. The order mandated all wireless… (More)
—A fundamental task in a wireless sensor network is to broadcast some measured data from an origin sensor to a destination sensor. Since the sensors are typically small, power limited, and low cost, they are only able to broadcast low-power signals. As a result, the propagation loss from the origin to the destination nodes can attenuate the signals beyond… (More)
Among the challenging issues that affect the performance of wireless location techniques is the temporal and spatial variations of the channel, and the distribution of the scatterers, which introduce non-line-of sight errors at the base station. This paper develops a technique for addressing this problem by exploiting the topology of the cellular network.
Location finding for CDMA subscribers using an antenna m a y at the base station is studied in this paper. Two methods are considered for radio location that are based on time of arrival (TOA) and angle of arrival (AOA) measurements. For TOA estimates, a maximum likelihood algorithm and a practical structure are proposed when an antenna array is available.… (More)
Overlapping multipath propagation is one of the main sources of mobile-positioning errors, especially in fast channel fading situations. In this paper we present a technique for detecting the existence of overlapping fading multipath components. Such information is vital for accurate resolving of overlapping multipath components as well as avoiding… (More)
Phase noise causes significant degradation in the performance of Orthogonal Frequency Division Multiplexing (OFDM) based wireless communication systems. In the proposed compensation scheme, the communication between the transmitter and receiver blocks consists of two stages. In the first stage, block-type pilot symbols are transmitted and the channel… (More)
This paper describes a multi-relay strategy for wireless networks and examines the influence of imperfect channel information on system performance. A modified relay scheme is proposed to compensate for such imperfections.