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Compared to frequency division duplex (FDD) and time division duplex (TDD), full duplex (FD) is effective in improving frequency efficiency and in achieving flexible resource assignment. The key challenge to actualizing FD in cellular systems is to suppress sufficiently self-interference (SI) from the own transmitter using antenna isolation, an analog self-interference canceller, and a digital self-interference...
This paper proposes a parallel double Gray mapping scheme that is suited to circular quadrature amplitude modulation (QAM) constellations using partial channel coding associated with collaborative decoding. Using the proposed scheme, We compare the bit error rate (BER) performance of circular 1024QAM and 2048QAM schemes to that of rectangular 1024QAM and cross 2048QAM schemes, respectively. Computer...
This paper proposes a fast initial cell search method based on two-step frequency offset estimation for a small cell in Long Term Evolution (LTE) heterogeneous networks using different frequency spectra. In the proposed cell search method, a set of user equipment (UE) first estimates the frequency offset of a received primary synchronization signal (PSS) from a macrocell and computes the frequency...
This paper presents broadband packet wireless access schemes based on Variable Spreading Factor (VSF)-Orthogonal Frequency and Code Division Multiplexing (OFCDM) in the forward link and Variable Spreading and Chip Repetition Factors (VSCRF)-CDMA in the reverse link for the systems beyond IMT-2000. In our design concept for wireless access in both links, radio parameters such as the spreading factor...
This paper proposes Faster-than-Nyquist (FTN) signaling with non-uniform compression factors for orthogonal frequency division multiplexing (OFDM)/offset quadrature amplitude modulation (OQAM). In the proposed FTN signaling scheme, a compression factor lower than the average one in the assigned resource blocks (RBs) is used for the central subcarrier region, and the compression factor is increased...
This paper investigates the block error rate (BLER) performance of time and frequency domain compression for Faster-than-Nyquist (FTN) signaling in frequency-selective fading channels. In this paper, we use FTN mapping method in which FTN symbols are mapped onto orthogonal frequency division multiplexing (OFDM)/offset quadrature amplitude modulation (OQAM) symbol positions at a transmitter and a turbo...
This paper presents the initial cell search time performance based on Long Term Evolution (LTE) synchronization signals employing precoding vector switching (PVS) transmit diversity in heterogeneous networks. We focus on the effect of PVS transmit diversity to mitigate the influence of co-channel interference in heterogeneous networks with the same frequency spectrum between a macrocell and small...
This paper proposes a fast initial cell search method based on frequency offset estimation for Long Term Evolution (LTE) heterogeneous networks using separate frequency spectra between a macrocell and a small cell. When using the primary synchronization signal (PSS) and secondary synchronization signal (SSS) in the LTE radio interface, the initial cell search time for small cells with a high carrier...
This paper presents the initial cell search time performance based on Long Term Evolution (LTE) synchronization signals employing the same frequency spectrum for heterogeneous networks including indoor small cells. We assume the indoor small cell models in hot zone buildings that are specified in the 3rd Generation Partnership Project (3GPP) technical report. System-level simulation results show that...
This paper presents the effects of antenna receiver diversity with Faster-than-Nyquist (FTN) signaling employing orthogonal frequency division multiplexing (OFDM)/offset quadrature amplitude modulation (OQAM) in a multipath fading channel. We utilize a method for mapping an FTN signal to an OFDM based orthogonal basis function. Based on link-level simulations, we show that antenna receiver diversity...
This paper proposes local cell cluster-specific primary synchronization signal (PSS) sequence assignment and local cell-specific secondary synchronization signal (SSS) sequence assignment schemes for orthogonal frequency division multiple access (OFDMA) heterogeneous networks. The proposed synchronization signal (SS) sequences are based on those of the Long-Term Evolution (LTE) radio interface. We...
This paper investigates the throughput performance using adaptive modulation and coding (AMC) focusing on the causes of impairment to Orthogonal Frequency Division Multiplexing (OFDM) - Multiple-Input Multiple-Output (MIMO) multiplexing. We first investigate the influence of a limited number of modulation and coding schemes (MCSs) and channel estimation error for MCS selection based on mutual information...
This paper presents a comparative study of single-carrier (SC)-frequency division multiple access (FDMA) and OFDMA using turbo soft interference cancellation (SIC) from the viewpoint of throughput for multiple-input multiple-output (MIMO) spatial division multiplexing (SDM). In turbo SIC, interference from other transmission streams is generated based on the log-likelihood ratio (LLR) at the turbo...
This paper presents the average block error rate (BLER) performance for linear minimum mean-square error (LMMSE) based iterative decision-directed channel estimation (IDDCE) associated with the turbo frequency domain equalizer (FDE) for discrete Fourier transform (DFT)-precoded Orthogonal Frequency Division Multiple Access (OFDMA). In the proposed IDDCE, estimated channel responses, which are used...
This paper presents the effect of joint modulation and coding scheme (MCS) selection on a turbo soft interference canceller (SIC) for OFDM-MIMO multiplexing using adaptive modulation and coding (AMC). We use a turbo SIC to detect signals by performing iterative interference cancellation using soft-symbol estimates based on the a posteriori log-likelihood ratio (LLR) at the Max-Log-MAP decoder output...
This paper presents the block error rate (BLER) performance of a posteriori log-likelihood ratio (LLR) computation methods at the output of a frequency domain equalizer (FDE) with antenna diversity reception using a low-rate turbo code for discrete Fourier transform (DFT)-precoded orthogonal frequency division multiple access (OFDMA). In the paper, we propose an a posteriori LLR computation method...
This paper proposes iterative decision-directed channel estimation (IDDCE) associated with the turbo frequency domain equalizer (FDE) for discrete Fourier transform (DFT)-precoded Orthogonal Frequency Division Multiple Access (OFDMA). By using soft-symbol estimations based on the extrinsic log-likelihood ratio (LLR) at the Max-Log-MAP decoder output and for the reference signal (RS), the accuracy...
This paper compares the block error rate (BLER) performance of open-loop (OL) transmit diversity schemes with four antennas in the uplink for discrete Fourier transform (DFT)-precoded orthogonal frequency division multiple access (OFDMA). One candidate is a quasi-orthogonal (QO) - space-time block code (STBC) in which four-branch minimum mean-square error combining (MMSEC) is achieved at the cost...
In orthogonal frequency division multiple access (OFDMA), time division multiplexing (TDM) based layer 1 (L1)/layer 2 (L2) control signals provide advantageous features such as a power saving effect using micro-sleep operation and a short round trip delay (RTD) for channel-dependent scheduling and adaptive modulation and coding (AMC) compared to a frequency division multiplexing (FDM) based structure...
This paper presents the average block error rate (BLER) performance of the star 16QAM scheme using iterative decision-directed channel estimation (DDCE) for discrete Fourier transform (DFT)-precoded orthogonal frequency division multiple access (OFDMA). The star 16QAM scheme achieves more efficient modulation compared to square 16QAM in that it decreases the actual required average received signal-to-noise...
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