Spatial Modulation is a newly developed concept for multi-antenna systems, which could greatly reduce the signal processing complexity and hardware implementation burden faced by these systems today. To improve the sp...
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ISBN:
(纸本)9781467362337
Spatial Modulation is a newly developed concept for multi-antenna systems, which could greatly reduce the signal processing complexity and hardware implementation burden faced by these systems today. To improve the spectral efficiency of spatial modulation system, a novel precoding scheme for downlink multi-user system is proposed in this paper. The precoding scheme not only cancels the inter-user interference, but also preserves the information embedded both in constellation symbols as well as in transmit antenna indexes, decomposing the system into independent single-user spatial modulation systems. Simulation results show that with a high transmission rate, the proposed scheme offers a smaller bit error rate than multi-user Zero Forcing precoding in practical SNR region. With the same base station antenna number and single-antenna user number, it also outperforms Zero Forcing precoding in terms of achievable sum rate. Furthermore, systems using our scheme could achieve a multi-user gain over single-user spatial modulation system.
It is well-known that the performance of the relay-based decode-and-forward (DF) cooperative networks outperforms the performance of the amplify-and-forward cooperative networks. However, this performance improvement ...
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It is well-known that the performance of the relay-based decode-and-forward (DF) cooperative networks outperforms the performance of the amplify-and-forward cooperative networks. However, this performance improvement is accomplished at the expense of adding more signal processing complexity (precoding/decoding) at each relay node. In this study, the authors tackle this signal processing complexity issue by proposing a Jacket-based fast method for reducing the precoding/decoding complexity in terms of time computation. Jacket transforms have shown to find applications in signalprocessing and coding theory. Jacket transforms are defined to be n x n matrices A = (a(jk)) over a field F with the property AA(dagger) nI(n), where A(dagger) is the transpose matrix of the element-wise inverse of A, that is, A(dagger) (a(kj)(-1)), which generalise Hadamard transforms and centre weighted Hadamard transforms. In particular, exploiting the Jacket transform properties, the authors propose a new eigenvalue decomposition (EVD) method with application in precoding and decoding of distributive multi-input multi-output channels in relay-based DF cooperative wireless networks in which the transmission is based on using single-symbol decodable space-time block codes. The authors show that the proposed Jacket-based method of EVD has significant reduction in its computational time as compared to the conventional-based EVD method. Performance in terms of computational time reduction is evaluated quantitatively through mathematical analysis and numerical results.
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