Journal of information and communication convergence engineering

The Korea Institute of Information and Commucation Engineering (한국정보통신학회)
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Low-Complexity Block Diagonalization Precoder Hardware Implementation for MU-MIMO 4×4

  • Khai, Lam Duc (Department of Computer Engineering, University of Information Technology, VNU-HCM)
  • Received : 2018.07.30
  • Accepted : 2018.11.29
  • Published : 2019.03.31
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Abstract

In this paper, we present the block diagonalization (BD) algorithm for the multiple-user multiple input multiple output (MU-MIMO) $4{\times}4$ system using specific purpose processor (SPP) hardware. Our objective is to improve the single-user MIMO (SU-MIMO) system using the MU-MIMO technology, which is remarkably fast and allows more users to connect simultaneously. To that end, our MU-MIMO precoder uses the BD algorithm to ensure signal integrity when connecting multiple users; but remains accurate and stable. However, a precoder that uses the BD algorithm is computationally complex; therefore, we use an SPP with special functions designed to compute the BD algorithm. The implementation test results show that our SPP computes the BD algorithm faster than the software solution.

Keywords

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Fig. 1. SISO vs. MIMO system.

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Fig. 2. MU-MIMO system.

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Fig. 3. MU-MIMO 4x4 system.

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Fig. 4. Channel state information matrix.

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Fig. 5. IUI is eliminated by the BD method.

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Fig. 6. Block H1, H2, H3, H4.

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Fig. 7. SVD of the matrices Hk (k = 1:4).

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Fig. 8. Matrix Σk and $V_k^b$.

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Fig. 9. Matrix Σk and ${Ṽ}_k^n$.

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Fig. 11. Processing unit.

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Fig. 12. State machine of controller unit.

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Fig. 13. Software vs hardware implementation.

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Fig. 10. SPP architecture and instruction format.

Table 1. Operations in the SPP

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Table 2. BD implementation steps and corresponding SPP operations

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Table 3. Number of cycles of each function

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Table 4. Accuracy of each function

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Table 5. Software vs Hardware Processing Time

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Cited by

  1. An Enhanced Precoder for Multi User Multiple-Input Multiple-Output Downlink Systems vol.10, pp.13, 2019, https://doi.org/10.3390/app10134547