25 Feb 2011 | A. Salman Avestimehr, Member, IEEE, Suhas N. Diggavi, Member, IEEE, and David N. C. Tse, Fellow, IEEE
This paper presents a deterministic approach to analyze information flow in wireless networks, focusing on the maximum achievable rate of information flow in a network with a single source, single destination, and arbitrary relay nodes. The authors propose a deterministic channel model that captures key wireless properties such as signal strength, broadcast, and superposition. This model generalizes the max-flow min-cut theorem for wired networks and provides an exact characterization of network capacity. Using insights from this deterministic analysis, the authors design a new quantize-map-and-forward scheme for Gaussian networks. This scheme allows relays to quantize received signals at the noise level, map them to random Gaussian codewords, and forward them, enabling the destination to decode the source's message. The scheme achieves the cut-set upper bound within a gap that is independent of channel parameters, with a gap of 1 bit/s/Hz for the single-relay and two-relay Gaussian diamond network. The scheme is universal, requiring no knowledge of channel parameters to achieve the rate supported by the network. The results are extended to multicast, half-duplex, and ergodic networks. The deterministic model is shown to provide insights into wireless communication, revealing that many existing schemes are suboptimal. The paper also demonstrates that the quantize-map-and-forward strategy outperforms existing strategies like amplify-and-forward and Gaussian compress-and-forward in terms of universal approximation. The deterministic model is used to analyze various relay networks, showing that the optimal strategy involves shuffling and linearly combining received signals at various levels and forwarding them. The main result is that the quantize-map-and-forward scheme is universally approximate for arbitrary noisy Gaussian relay networks.This paper presents a deterministic approach to analyze information flow in wireless networks, focusing on the maximum achievable rate of information flow in a network with a single source, single destination, and arbitrary relay nodes. The authors propose a deterministic channel model that captures key wireless properties such as signal strength, broadcast, and superposition. This model generalizes the max-flow min-cut theorem for wired networks and provides an exact characterization of network capacity. Using insights from this deterministic analysis, the authors design a new quantize-map-and-forward scheme for Gaussian networks. This scheme allows relays to quantize received signals at the noise level, map them to random Gaussian codewords, and forward them, enabling the destination to decode the source's message. The scheme achieves the cut-set upper bound within a gap that is independent of channel parameters, with a gap of 1 bit/s/Hz for the single-relay and two-relay Gaussian diamond network. The scheme is universal, requiring no knowledge of channel parameters to achieve the rate supported by the network. The results are extended to multicast, half-duplex, and ergodic networks. The deterministic model is shown to provide insights into wireless communication, revealing that many existing schemes are suboptimal. The paper also demonstrates that the quantize-map-and-forward strategy outperforms existing strategies like amplify-and-forward and Gaussian compress-and-forward in terms of universal approximation. The deterministic model is used to analyze various relay networks, showing that the optimal strategy involves shuffling and linearly combining received signals at various levels and forwarding them. The main result is that the quantize-map-and-forward scheme is universally approximate for arbitrary noisy Gaussian relay networks.