Huiyue Yi

Nullspace-Based Secondary Joint Transceiver Scheme for Cognitive Radio MIMO Networks Using Second-Order Statistics

In this paper, we propose a practical nullspace-based secondary joint transceiver scheme for the coexistence of a secondary system and a primary system in cognitive radio MIMO (CR-MIMO) networks using second-order statistics. First, we propose a secondary transmission frame structure, and briefly describe the periodical nullspace sensing procedure for both the secondary transmitter (ST) and secondary receiver (SR). Then, we formulate nullspace-based secondary joint transceiver scheme by utilizing the nullspace at the ST as the secondary transmit precoding and the nullspace at the SR as the secondary receive beamforming from both theoretical and practical perspective. Furthermore, we focus on analyzing the effect of nullspace estimation errors on the performance of the primary system and the secondary system. Finally, simulations are presented to demonstrate the effectiveness of the proposed secondary joint transceiver scheme along with the theoretical analysis.

Null Space-Based Precoding Scheme for Secondary Transmission in a Cognitive Radio MIMO System Using Second-Order Statistics

In this paper, we propose a null space-based precoding scheme for secondary transmission in a cognitive radio multiple-input multiple-output (CR-MIMO) network under the assumption that time-division-duplex is employed by the primary transmission. First, the secondary transmitter periodically senses the transmitted signals from the primary users and estimates the corresponding covariance matrix. Then, subspace techniques are utilized to estimate the noise subspace of this covariance matrix, and the dimension of the noise subspace is estimated using information theory criteria (AIC or MDL). Finally, the obtained null space is used as the precoding matrix for the secondary transmission, which effectively avoids the interference induced by the secondary transmission at the primary users. Moreover, the achievable capacity of the secondary MIMO channel by the proposed scheme is derived. Simulations are performed to show the efficacy of the proposed scheme.

Comparing Effects of Carrier Frequency Offset on Generalized Multi-Carrier and OFDM Systems

The carrier frequency offset (CFO) could destroy the orthogonality of OFDM subcarriers and induce the inter-carrier interference (ICI) spread. However, the generalized multi-carrier (GMC) system reflects different interference characters in the presence of CFO. In this paper, we exactly analyze the CFO effect on GMC, which multiplexes several single band single carrier based frequency division multiple access (SC-FDMA) streams in frequency domain, under the scenario of additive white Gaussian noise (AWGN) channels. A closed-form expression of signal to interference plus noise ratio (SINR) is derived for the GMC systems in the presence of CFO. Furthermore, the bit error rate (BER) performance analysis is also performed in comparison with the traditional OFDM system for both uncoded and coded environments. Analysis and simulation results show that the feature procedure of discrete Fourier transform (DFT) spread may condense the CFO-induced interference in the first symbol of each subband, resulting in less interference in other symbols. Such condensing procedure can provide robustness against the CFO effect, which also lies on the subband bandwidth for GMC systems. In contrast to the conventional OFDM system, GMC exhibits more robustness when each subband width is designed for 4 times larger than the subcarrier spacing.

Frequency domain discrete fourier transform spread generalized multi-carrier system and its performance analysis

Discrete fourier transform spread generalized multi-carrier (DFT-S-GMC) scheme is a promising candidate for the uplink transmission of the new generation broadband mobile communications due to its lower peak-to-average power ratio and its robustness to the multi-user interference if compared with the conventional orthogonal frequency division multiple (OFDM)-based transmission schemes. However, the time domain DFT-S-GMC system has a relatively high implementation complexity and is difficult to analyze its signal-to-interference plus noise ratio (SINR). In addition, the existing link-to-system mapping methods for OFDM-based systems cannot be utilized in the DFT-S-GMC systems. In this paper, we first propose a novel frequency domain transceiver model for the DFT-S-GMC system, which can effectively simplify the SINR analysis. Then, we derive the closed-form SINR expressions for the link-to-system mapping of DFT-S-GMC system with Alamouti-like space-time block-coding (STBC). It is demonstrated that the theoretical SINR expressions match the simulation results very well.

WLC20-2: Optimal Regions Planning for Adaptive Transmission Mode Selection Scheme

The adaptive transmission mode selection (ATMS) scheme increases the spectrum efficiency and the flexibility of radio resource management for the distributed wireless communication systems (DWCS). In this paper, different optimal regions are planned for the adaptively selected transmission modes, based on the received signal to noise ratio (SNR) from each access point (AP) and the required quality-of-service (QoS) of the mobile stations (MS).

SPC12-3: Cumulant-Based JAFE Algorithm in Spatially and Temporally Correlated Gaussian Noise

A cumulant-based joint angle-frequency estimation (CB-JAFE) algorithm for angle-frequency parameter estimation of independent nonGaussian sources is proposed. The proposed CB-JAFE algorithm, which utilizes the fourth-order cumulants of the spatio-temporal data, can effectively suppress the spatially and temporally correlated Gaussian noise with unknown correlation structure. Simulation results are carried out to demonstrate the effectiveness of the proposed algorithm compared with the JAFE algorithm.