Analysis of residual CFO impact on downlink massive MISO systems

Abstract

Massive antenna technologies provide a good power focusing gain for emerging communication systems. They can easily be integrated into an orthogonal frequency-division multiplexing (OFDM) system. However, OFDM is known to be prone to carrier frequency offset (CFO) due to the loss of the orthogonality among OFDM subcarriers. In this Letter, the authors investigate the impact of residual CFO (RCFO) on the downlink performance of massive multiple-input single-output (MISO) OFDM systems using matched-filter (MF) and maximum-ratio-transmission (MRT) precoders. Particularly, the exact mean-square-error (MSE) expressions of the equalised received signal of both MF and MRT systems are derived. Numerical simulations with Rayleigh fading channels are carried out to validate the analysis. The results show that the RCFO causes a MSE plateau compared to the ideal case of no CFO.

Performance Analysis of Frequency Domain Precoding Time-Reversal MISO OFDM Systems

“…This leads to the reduction of the NMSE and hence improves the SNR gain, especially when increasing BOFs (associated with the frequency diversity gain). In the case we increase the number of antennas, the NMSEs are also reduced thanks to the spatial diversity gain, which confirms the results of previous works [4], [5].…”

“…The FD/TR precoding combined with OFDM has been shown to be a simple and efficient technology [4]. However, up to now, the literature [4], [5] has only considered a BOF of one, which does not exploit the full advantage of TR. Furthermore, no performance analysis of the FD/TR precoding system, i.e., mean-square-error (MSE) of the received symbols, has been provided.…”

Focusing gain analysis of time-reversal precoding in MISO OFDM communication systems

“…Applying the lower incomplete Gamma function defined in (7) into (24), we achieve the approximated formula of T 1…”

“…As aforementioned, the FD/TR precoding system in previous works considered only different numbers of antennas [6,7] with the BOF implicitly equal to one. Recently, a suitable way of TR precoding in the frequency domain has been presented in [3].…”

Performance Analysis of Matched-Filter Precoded MISO-OFDM Systems in the Presence of Imperfect CSI

“…However, the system was assumed to be perfectly synchronized and the CSI was also assumed to be perfect. Recently, the mean-square-error (MSE) analysis of the impact of carrier frequency offset (CFO) on the MF precoded MISO-OFDM system has been investigated [10]. However, the perfect CSI was again assumed.…”