We have re-observed and re-analysed the optical spectrum of the Schweizer–Middleditch star, a hot subdwarf which lies along almost the same line-of-sight as the centre of the historic SN1006 supernova remnant (SNR). Although this object is itself unlikely to be the remnant of the star which exploded in 1006AD, Wellstein et al. (1999) have demonstrated that it could be the remnant of the donor s...

The development of future geolocation systems requires a fundamental understanding of the importance of various system parameters, such as the number of sensors, the SNR, bandwidth, and channel conditions. We consider the bounds on time-based geolocation accuracy when all sensors experience non-line-of-sight (NLOS) conditions. While location accuracy generally improves with additional bandwidth...

In this paper we analyze the energy efficiency of single-hop, multihop, cooperative selective decode-and-forward, cooperative incremental decodeand-forward, and even the combination of cooperative and non-cooperative schemes, in wireless sensor networks composed of several nodes. We assume that, as the sensor nodes can experience either non line-of-sight or some lineof-sight conditions, the Nak...

We consider a wireless network with a large number of nodes distributed over a line. Under line-of-sight propagation, this network has only one degree of freedom for communication. At high SNR, this one degree of freedom can be readily achieved by multi-hop. At low SNR, however, the performance is dominated by the power transfer in the network. We show that none of the existing architectures, n...

The integration of wideband and multiple-input multiple-output (MIMO) radio technologies represents a powerful tool for different wireless communication standards. In the test process of these systems, new strategies for MIMO channel modelling and characterisation are necessary in order to investigate how the frequency band and the bandwidth affect the system performance. In this paper, a MIMO ...

We report on a channel measurement campaign using body and personal area network devices, placed both in an office and on-body. Inspired by the theoretical work on cooperation between devices, which predicts MIMO-like capacity gains for co-operative systems, the capacity of MIMO and cooperating devices are examined. Significant capacity gain is observed, even under line-of-sight conditions in t...