Changes between Version 14 and Version 15 of BuildingCooperativeComm
- Timestamp:
- Aug 20, 2009, 12:17:46 PM (15 years ago)
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BuildingCooperativeComm
v14 v15 1 1 = On Building a Cooperative Communication System: Testbed Implementation and First Results = 2 2 3 Authors: Patrick Murphy, Ashutosh Sabharwal & Behnaam Aazha ing3 Authors: Patrick Murphy, Ashutosh Sabharwal & Behnaam Aazhang 4 4 5 5 == Abstract == 6 In this paper, we present the results from over-the-air experiments of a complete implementation of an amplify and forward cooperative communications system. Our custom OFDM-based physical layer uses a distributed version of the Alamouti block code, where the relay sends one of the branches of Alamouti encoded symbols. First we show analytically and experimentally that amplify and forward protocols are unaffected by carrier frequency offsets at the relay. This result allows us to use a conven- tional Alamouti receiver without change for the distributed relay system, thereby allowing cooperative systems to reuse components of current (non-cooperative) systems. Our full system implementation shows gains up to 5.5dB in peak power constrained networks. Thus, we can conclusively state that even the simplest form of relaying can lead to significant gains in practical implementations.6 We present the results from over-the-air experiments of a complete implementation of an amplify and forward cooperative communications link. Our custom OFDM-based physical layer uses a distributed version of th Alamouti block code, where the relay sends one of the branches of Alamouti-encoded symbols. First we show analytically and experimentally that amplify and forward protocols are unaffected by carrier frequency offsets at the relay. This result allows us to use a conventional Alamouti receiver without change for the distributed relay system, thereby allowing cooperative systems to reuse components of current (noncooperative) systems. Our full system implementation shows gains of up to 5.5dB in peak power constrained networks. Thus, we can conclusively state that even the simplest form of relaying can lead to significant gains in practical implementations. 7 7 8 8 == Preprint ==