Multihopping in wireless communication channels: Some solutions, some challenges

Urbashi Mitra
University of Southern California (USC)
Electrical Engineering

With the recent interest in large scale sensor networks, renewed attention at the physical layer has been afforded to communication networks wherein messages are transmitted via a chain of relays from source to destination. Due to propagation effects which cause distance dependent attenuation, a multihop approach has the potential to significantly reduce the overall transmission power needed to achieve a certain level of fidelity by decomposing a long distance link into multiple shorter links with improved channels. However, multihopping comes at a price. There is potential for increased delay, error propagation, and interference. Herein, multihopping networks are investigated from multiple perspectives and the challenges unique to such networks are underscored. Exemplar problems include: distributed space-time coding for multihop networks and the associated achievable performance which requires analysis of so-called product channels; a new packet scheduling problem over multihop link to achieve minimal energy consumption; and a novel error exponent analysis of communication over multihop networks which enables the consideration of delay versus performance for such networks. Preliminary results and future directions will be highlighted.

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