Shu Feng

An Efficient Power Allocation Scheme for Leakage-Based Precoding in Multi-Cell Multiuser MIMO Downlink

To enhance the sum rate of maximizing signal-to-leakage-and-noise ratio (Max-SLNR), a power allocation (PA) scheme that combines the noise and interference whitening, the singular value decomposition, and the water-filling algorithms is proposed for Max-SLNR per user as opposed to the per antenna of users. Simulation shows that the proposed approach produces higher sum rate than the Max-SLNR per antenna scheme and the Max-SLNR per user with equal PA (EPA). It is also better in bit error rate than the Max-SLNR per user with EPA in the presence of shadow fading and receiving antenna correlation.

PIC-based iterative SDR detector for OFDM systems in doubly-selective fading channels

OFDM data detection in doubly-selective fading channels requires high complexity due to intercarrier interferences (ICI). We present a low-complexity receiver consisting of a semidefinite relaxation (SDR) based detector and parallel interference cancellation (PIC). The entire band is divided into clusters of adjacent subcarriers. SDR is applied on each cluster while PIC tackles ICI from other clusters. An upper bound of ICI power is derived and used to omit far-away clusters in performing PIC. Finally, an adaptive detector based on PIC, PIC-based SDR and the snap-shot SNR in channel is proposed to achieve a better tradeoff between complexity and performance.

Improved joint compensation scheme of transmitter and receiver IQ imbalances in OFDM systems

The in-phase and quadrature-phase (IQ) imbalances can be present at both the transmitter and receiver in OFDM systems and lead to system performance degradation. An improved LS based joint channel and IQ imbalance estimation scheme is proposed. Simulations show that the improved scheme with only two training symbols per frame could achieve better BER performance than the original LS compensation scheme using up to 32 training symbols per frame.