Intra‐volume, centralised array concept for improved public‐safety communications

The author report on the testing and measurements of an intra‐volume centralised array concept suitable for public‐safety communications in buildings. The centralised array concept refers to the use of several small communication devices that are arbitrarily placed in an area and hence create a real‐time communication network. The overall concept is to use randomly located (or arbitrarily placed) wireless devices in a coordinated manner in order to increase the radio‐frequency signal level otherwise at unreachable locations. In a typical ad‐hoc network, the transmission range of any communication link in that path is limited. We seek to extend the radio‐frequency coverage within the array volume by using two or more nodes as elements of a phased array. The measurement results presented here, collected in real‐world environments, along with simulations based on real‐world data demonstrate that the centralised array technique can provide useful gain, up to 10 dB with only four elements. Both the measurements and simulations also indicate a typical gain of 2 to 6 dB, using only two elements. Analysis of the phase indicates a phase alignment of ±45° achieves within 1 dB of the maximum gain.