An algorithm for wireless relay placement

Abstract

An algorithm is given for placing relays at spatial positions to improve the reliability of communicated data in a sensor network. The network consists of many power-limited sensors, a small set of relays, and a receiver. For each sensor, the receiver receives a direct signal as well as an indirect signal from one of the available relays. The relays rebroadcast the transmissions in order to achieve diversity at the receiver. Both amplify-and-forward and decode-and-forward relay networks are considered. Channels are modeled with Rayleigh fading, path loss, and additive white Gaussian noise. Performance analysis and numerical results are given.

On relaying for wireless industrial communications: Is careful placement of relayers strictly necessary?

“…Some of the important questions in the design of relaying schemes include the placement of relay nodes [10] and the allocation of relayers to sources, see e.g. [18], [19], [20].…”

“…It is intuitively clear (and substantiated by several publications, including [10]) that such an approach is especially promising if the relay has "good" channels to both source and destination, like for example when a relay is placed in the middle between the source and the destination. However, in many industrial settings it might for practical reasons not be possible or easy to place relay nodes at a desired position, for example because this position is inaccessible or dangerous to human staff.…”

The effects of relay behavior and position in wireless industrial networks

“…However, the choice of position and behavior for the relay nodes were only examined for one type of channel, a fading channel without line of sight. Some research on best relay node placement was done in, e.g., [8,9]. In [8] the authors present a wireless relay placement algorithm for wireless sensor networks, which attempts to reduce the sensoraverage probability of error.…”

“…Some research on best relay node placement was done in, e.g., [8,9]. In [8] the authors present a wireless relay placement algorithm for wireless sensor networks, which attempts to reduce the sensoraverage probability of error. In the case of industrial communications, the worst case error probability is of essence as we consider real-time data traffic.…”

“…In the case of industrial communications, the worst case error probability is of essence as we consider real-time data traffic. Further [8] assumes no retransmission scheme, and instead each packet is always transmitted twice, from the source and from the relayer, and a diversity combining algorithm is made at the final destination. The results from [9] shows that the choice of path loss model and fading distribution model effect the optimal amount of relay nodes as well as their positions.…”