Optimizing Arrays of Randomly Placed Wireless Transmitters for Receivers Located Within the Array Volume

Abstract

We investigate the potential of using arbitrarily placed wireless transceivers to increase the probability of maintaining a communication link in an electrically harsh environment. Specifically, we adapt a well-known matrix-based array optimization technique to the case when the transmitting elements exist in a complex environment and the receiver is not in the far-field of the array. Study of array performance in a non-ideal setting represents an important step in determining the feasibility of using this optimization technique for ad hoc wireless arrays within a building. Measures of array performance consist of median values for the directivity or gain, the total power at the receiver location, and the power per transmitter. The simulation results include array performance in the presence of a lossy dielectric corner to study the effects of building floors and walls. Our results show the median of the optimized directivity or gain for the frequencies of interest with simple boundaries is within 3 dB of that for the optimized configuration in free space.Index Terms-Ad hoc array, arbitrary array optimization, emergency responder communications, random array.

Measurements of Randomly Placed Wireless Transmitters Used as an Array for Receivers Located Within the Array Volume With Application to Emergency Responders

“…The simulation results in our earlier work [2] and [15] point out some key impacts to field-implementation. First, diminishing returns in total received power occur after the array contains a small number of transmitters, approximately four transmitters for the optimized case and six to eight transmitters for the co-phased case.…”

“…(Co-phasing means adjusting the transmitted signal phase such that all the received signals have the same phase, e.g., [16], [17].) Second, for this same small number of transmitters, the modified directivity results [ [2], (11)] are not significantly different for the optimized and co-phased results. Thus, we propose the following algorithm to obtain the co-phased results, with the recognition that the algorithm also provides a reasonable approximation of the optimized modified directivity.…”

“…Port 1 of the network analyzer connects to a single monopole, which represents the receiver. Additional details on the experiment are contained in Chapter 5 of [18].…”

“…we present experiment results that implement the proposed algorithm in our earlier work [2], with the inclusion of additional representative boundary configurations beyond those used in the initial simulation results.…”

“…All these works assume a receiver in the far-field rather than within the volume of the array, as was the case of [2]. A method for adapting radiated power for receivers located in the near-field is discussed in [13], but more relevant to our work, [14] discusses optimizing arrays in arbitrary environments.…”