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Browsing DSP Publications by Subject "achievable rates"
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Item Rate-constrained Relaying: A Model for Cooperation with Limited Relay Resources(2005-06-01) Sabharwal, Ashutosh; Mitra, Urbashi; Center for Multimedia Communications (http://cmc.rice.edu/)In this paper, the impact of limited resources on achievable rates in relay channels is investigated. Resource limitation is modeled as a rate constraint, Rbar, which constrains the rate at which a relay can reliably decode or source-code data. With this constraint in hand, the achievable rates for several protocols are derived and compared: decode-and-forward, estimate-and-forward, a Markovian amplify-and-forward and a hybrid scheme that combines decode-and-forward and amplify-and-forward. The key result is that the relative performance of these protocols in the unconstrained case is not maintained in rate constrained scenarios. The case of severe resource limitation (Rbar --> 0) is also considered. Previously established rates for unconstrained decode-and-forward and estimate-and-forward are re-examined in the context of optimal parameters and asymptotic performance. For most relay locations (topologies), either decode-and-forward and estimate-and-forward offers superior performance. However, for severe rate constraints, amplify-and-forward generally offers the best performance.