Hybrid Precoding for mmWave MIMO Systems With Overlapped Subarray Architecture

Abstract

Traditional precoding is incompatible with millimetre wave (mmWave) multiple input multiple output (MIMO) systems due to hardware costs and power consumption. As a result, hybrid precoding is being considered as a promising technology for balancing hardware complexity and system performance. This paper proposes a hybrid precoding technique for overlapped subarrays (OSA) architecture in mmWave MIMO systems. It exploits the OSA's structure to decompose the hybrid precoding problem into a series of 𝐿 𝑡 𝑁 𝑠 /2 subproblems and then solves them iteratively, where 𝐿 𝑡 and 𝑁 𝑠 are the numbers of RF chains and transmitted data streams, respectively. First, the proposed scheme determines the analog and digital precoding submatrices of each OSA iteratively and then constructs the analog and digital precoding matrices of the whole OSA architecture. The digital precoding submatrix of each OSA is determined from each vector in the OSA submatrix. The results show that the proposed hybrid precoding for the OSA architecture outperforms the successive interference cancellation (SIC)-based hybrid precoding for non-overlapped SA (NOSA) and provides performance close to the fullyconnected (FC) spatially sparse hybrid precoding, despite requiring less hardware and computational complexities.

Performance analysis of linear detection for uplink massive MIMO system based on spectral and energy efficiency with Rayleigh fading channels in 3D plotting pattern

“…Recently, several low complexity algorithms for hybrid precoding and combining in 5G mmWave massive MIMO systems have been proposed and studied [33][34][35]. In [33], researchers proposed a hybrid precoding/combining algorithm based on the simultaneous orthogonal matching pursuit technique and demonstrated comparable performance to an optimal digital beamformer.…”

“…Additionally, ref. [35] proposed using an iterative hybrid precoding for overlapped subarray architecture to improve the spectral efficiency of the subarray architecture. The work in [35] showed that using an overlapped subarray architecture can improve spectral efficiency while still lower than the full array architectures.…”

Fast Iterative Hybrid Precoding and Combining With Momentum Gradient Descent and Newton’s Method for Millimeter Wave MIMO Systems

“…In the literature, there are two types of hybrid precoding and combining techniques: full array [7], [8] and subarray [21]- [23]. In the full array structure, every RF chain is linked to all the antenna elements, whereas in the subarray arrangement, each RF chain is connected to a portion of the antenna elements.…”

Direct Conversion of Hybrid Precoding and Combining From Full Array Architecture to Subarray Architecture for mmWave MIMO Systems

“…Recently, SA architectures have received a lot of attention because of their reduced complexity. SA architectures can be categorized into fixed SA [8], [15]- [22] and dynamic SA (DSA) [23]- [7], [27]. A closed-form solution for fully connected hybrid precoding based on OFDM is derived in [7] for mmWave systems.…”

“…Under the assumption that linear zero-forcing was utilized at the digital baseband, the complicated hybrid precoder optimization problem was reduced to an eigenvalue maximization problem. To increase the spectral efficiency of the SA design, the authors of [22] proposed an overlapping SA architecture with iterative hybrid precoding. The results showed that the overlapped SA architecture, while slightly more complex in terms of hardware than the fixed SA architecture, can improve spectral efficiency while still being less complex than the DSA and FA structures.…”