In this paper, we propose trellis-coded quantization (TCQ)-based limited-feedback techniques for massive multiple-input single-output (MISO) frequency-division duplexing systems in temporally and spatially correlated channels. We exploit the correlation present in the channel to effectively quantize channel direction information (CDI). For multiuser systems with matched-filter precoding, we show that the number of feedback bits required by the random vector quantization codebook to match even a small fraction of the perfect-CDI signal-to-interference-plus-noise ratio performance is large. With such large numbers of bits, the exhaustive search required by conventional codebook approaches makes them infeasible for massive MISO systems. Motivated by this, we propose a differential TCQ scheme for temporally correlated channels that transforms the source constellation at each stage in a trellis using 2-D translation and scaling techniques. We derive a scaling parameter for the source constellation as a function of the temporal correlation and the number of base station antennas. We also propose a TCQ-based limited-feedback scheme for spatially correlated channels, where the channel is directly quantized without performing decorrelation at the receiver. Simulation results show that the proposed TCQ schemes outperform the existing noncoherent TCQ (NTCQ) schemes, by improving the spectral efficiency and beamforming gain of the system. The proposed differential TCQ also reduces the feedback overhead of the system compared with the differential NTCQ method.
['Jawad Mirza', 'Mansoor Shafi', 'Peter J. Smith', 'Pawel A. Dmochowski']
Limited-Feedback Massive MISO Systems With Trellis-Coded Quantization for Correlated Channels