This paper describes the implementation of a multi-mode MIMO detector based on the concept of partially reconfigurable ASIP (rASIP). The multi-mode detector can support three different detection algorithms which are the Maximum Ratio Combining, the linear Minimum Mean Square Error (MMSE) detection, and the MMSE Successive Interference Cancellation. The detection algorithms also support different antenna configurations and modulation schemes. The rASIP is based on a Coarse-Grained Reconfigurable Architecture (CGRA), which is designed for efficient architectural support of matrix operations. A matrix inversion algorithm, which is used for the preprocessing of different detection algorithms, is mapped on the CGRA. By integrating a processor with the CGRA, the variations in the control path of different algorithm configurations can be handled efficiently. To the best of our knowledge, we show, for the first time that, a CGRAbased multi-mode MIMO detection is extremely efficient and matches the performance of dedicated ASIC implementation.

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In this contribution we investigate the performance of the UMTS Long Term Evolution (LTE) physical layer using turbo coding and 64QAM with Gray mapping. We show how the mapping of systematic and parity bits to the six different bit positions defining one complex 64QAM symbol influences the convergence of the turbo decoder and thereby the bit error rate (BER) performance as well as number of necessary decoding iterations. Exploiting the unequal error protection (UEP) property of Gray mapped 64QAM results in an SNR performance gain of approximately 2 dB for the non-iterative system and in addition leads to a significant reduction of the necessary decoding iterations when iterative decoding is performed.

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SUMMARYIn this contribution we investigate the performance of the universal mobile telecommunications system (UMTS) long-term evolution (LTE) physical layer using turbo coding and 64QAM with Gray mapping. We show how the mapping of systematic and parity bits to the six different bit positions defining one complex 64QAM symbol influences the convergence of the turbo decoder and thereby the bit error rate (BER) performance as well as number of necessary decoding iterations. Exploiting the unequal error protection (UEP) property of Gray mapped 64QAM results in an signal-to-noise ratio (SNR) performance gain of approximately 2 dB for the non-iterative system and leads to goodput gains especially in regions of low SNR.