Yuanrun Teng

Grouping adaptive modulation method for burst mode OFDM transmission system

This paper proposes an orthogonal frequency division multiplexing system with grouping adaptive modulation method (GAM-OFDM). The salient feature of the proposed method is to enable the reduction of required transmission bits for adaptive modulation information to be used in the demodulation process at the receiver. This paper also proposes the estimation method for the received CNR (carrier to noise power ratio) at another terminal by using the preamble symbols transmitted from that terminal. This paper presents the computer simulation results to verify the channel capacity and signal quality of the proposed GAM-OFDM system.

Complexity reduced maximum likelihood detection for SDM-OFDM system

This paper proposes two complexity reduced maximum likelihood detection (MLD) methods for SDM-OFDM system to exploit the spatial diversity so as to achieve the improved transmission quality. The proposed methods enable to outperform the other suboptimal detection methods and achieve the near MLD performance with significant reduction of calculation complexity. The various computer simulation results confirm that the proposed methods could realize the above targets and might be promising solution in practical systems.

Performances of multicarrier system with time and frequency domain spreading for wireless communications

This paper evaluates the performances of the multi-carrier system with both time and frequency domain spreading for indoor and outdoor wireless environments. The salient feature of the two-way spreading is to enable the achievement both of the time and frequency diversity gains under time varying fading channels. This paper recommends employing the multi-carrier - direct sequence - code division multiplexing access with frequency spread coding (MC-DS-CDMA/FSC) method and the orthogonal frequency division multiple access with time and frequency code division multiplexing (OFDMA-TFCDM) method to implement two-way spreading for downlink and uplink transmission, respectively. The various computer simulation results confirm that these two methods could provide the better transmission quality than the conventional methods under indoor and outdoor wireless communication environments.

Performance Evaluations of DCT Interpolation-Based Channel Estimation Method for MIMO-OFDM System

This letter proposes to employ the Discrete Cosine Transform (DCT) interpolation-based channel estimation (DCTI-CE) method for practical MIMO-OFDM (Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing) system so as to achieve its potential ability for enabling high transmission data rate. The various computer simulations are conducted to evaluate the DCTI-CE method in MIMO-OFDM system under the multipath fading channel for wireless LANs.

Performance of DCT interpolation-based channel estimation method for MIMO-OFDM systems

The MIMO-OFDM (multiple input multiple output-orthogonal frequency division multiplexing) system recently received considerable attention because of its potential ability to enable the higher transmission data rate while keeping the high signal quality. In practical MIMO-OFDM systems, the efficient and highly accurate channel estimation method is the mandatory requirement to achieve the potential system performance over MIMO channels. This paper proposes the discrete cosine transform (DCT) interpolation-based channel estimation (DCTI-CE) method, which could meet the above requirements. The salient feature of the proposed DCTI-CE method is to enable the estimation of all link channel responses with high accuracy by using only one preamble symbol even under the severe multi-path fading channel for wireless LAN systems.

Adaptive Slot and Bit Allocation Method for OFDMA Transmission Systems

This paper proposes the orthogonal frequency division multiple access (OFDMA) transmission scheme with an adaptive slot and bit allocation method for the multi-user wireless LAN (WLAN) systems. From the fact that the radio links between different users and base station experience the independent multi-path fading, this paper proposes a priority-based adaptive slot and bit allocation method in conjunction with a swapping algorithm to assign the suitable slots and modulation methods to all users. The proposed method can achieve the higher efficient usage of frequency resource than that for the conventional fixed slot assignment with adaptive bit allocation method. This paper presents various computer simulation results to evaluate the proposed method and demonstrates that the proposed method can achieve the higher frequency resource utilization with less computation complexity and with keeping the required signal quality over the severe frequency selective fading channels

Proposal of adaptive subchannel and bit allocation method for OFDM access wireless LAN systems

This paper proposes an adaptive subchannel and bit allocation method for OFDMA (orthogonal frequency division multiple access) based wireless LAN systems. The proposed adaptive subchannel and bit allocation method combines the adaptive subchannel allocation technique and adaptive modulation technique to improve the channel capacity of OFDMA system. This paper presents computer simulation results to demonstrate that the proposed method can achieve the higher frequency bandwidth efficiency and excellent signal quality even under severe frequency selective fading environment for point-to-multipoint wireless LAN systems.

Complexity Reduced Maximum Likelihood Detection for SDM-OFDM System

This paper proposes two complexity reduced maximum likelihood detection (MLD) methods for SDM-OFDM system to exploit the spatial diversity so as to achieve the improved transmission quality. The proposed methods enable to outperform the other suboptimal detection methods and achieve the near MLD performance with significant reduction of calculation complexity. The various computer simulation results confirm that the proposed methods could realize the above targets and might be promising solution in practical systems.