Abstract
This paper studies the uplink and downlink achievable rates for large-scale multiple-input–multiple-output (MIMO) systems, assuming perfect and imperfect channel state information under the effect of Doppler shift. Different from the previous relevant work, we consider a multiuser system scenario, where a full-duplex mode worked in the multicell base stations, and maximum-ratio combining/maximum-ratio transmission is applied at the receiver end. Then, we derive the asymptotic uplink and downlink sum rate by utilizing the large number theorem and considering the performance comparison between the perfect and imperfect channel. In addition, the impact of the Doppler shift on the system performance (e.g., the uplink and downlink sum rates) is analyzed via the simulation results.
Highlights
D UE to its high-frequency spectrum and energy utilization, security, and robustness, large-scale multiple-input– multiple-output (MIMO) systems are well suited for the future broadband, digital network architectures for Internet of Things (IoT) and cloud service interconnection
It is pointed out that if the base station (BS) can obtain the ideal channel state information (CSI), the transmit power per user can be reduced 1/M, and if the BS needs to estimat√e the channel, the transmit power per user can be reduced to 1/ M
For the multicell uplink transmission, this paper proposes an optimal linear receiver by maximizing the signal-to-interference-plus-noise ratio (SINR) and deduces the achievable rates in closed forms
Summary
D UE to its high-frequency spectrum and energy utilization, security, and robustness, large-scale multiple-input– multiple-output (MIMO) systems are well suited for the future broadband, digital network architectures for Internet of Things (IoT) and cloud service interconnection. When the number of antennas is large enough, since the linear processing method effectively suppresses the SI, the spectral efficiency of the entire smart worker almost doubles that of the time-division duplex half-duplex system. The combination of the full-duplex and large-scale antenna technologies can well satisfy the requirements of the future 5G communications, which has been studied widely in [7]–[9]. In [9], multiple pairs of users exchanged information with the aid of full-duplex relays with large-scale antennas, and proposed an optimal power allocation algorithm to minimize the total energy consumed by the system. Zhang studied the effect of the power scaling on the spectrum and energy efficiency in a large-scale two-way relay system [7]. We have studied the influence of the Doppler shift in a single-cell scenario on a full-duplex massive MIMO communication system. Notations: The symbols used in this paper are as follows: (A)T, (A)H, tr (A), A , and E {} denote the matrix transpose, conjugate transpose, matrix trace, the Euclidean norm, and expectation, respectively; [A]nn denotes the n × n diagonal entry of the matrix A; IM represents the M × M identity matrix. x ∼ CN (0, σijI) represents that x is a circularly symmetric complex-Gaussian vector whose entry’s mean and variance are 0 and σij, respectively
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