Search

In this paper, we propose a low-complexity joint detection of sector cell index and integer carrier frequency offset for a long-term evolution downlink system. In order to implement a low-cost detection scheme, a primary synchronization signal used for joint parameter estimation is grouped into a number of subsets so that the pilots in each subset are strongly correlated. The estimation performance and the computational load of the proposed scheme are compared with those of the commonly used conventional detection scheme using a differential correlation to remove common channel effects. It is found that the proposed scheme can jointly detect the cell index and integer carrier frequency offset with higher accuracy and much lower complexity, compared with the conventional scheme. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A method to obtain high diversity gain is proposed by spatial phase coding (SPC) in the cooperative multiple input multiple output‐orthogonal frequency division multiple access (MIMO‐OFDMA) system. SPC provides improved diversity gain dramatically in proportion to the number of received paths although the one‐bit feedback information is used. Moreover, the cooperative MIMO‐OFDMA system has received paths without additional antennas more than the conventional MIMO‐OFDMA system. Therefore, SPC can improve reliability in the cooperative MIMO‐OFDMA system effectively. [ABSTRACT FROM AUTHOR]

In a wireless communication system, the performance of the system is degraded due to the attenuation of the signal by path loss when a user is distant from the base station. For improvement of the system in this case, a new scheme is proposed. In conventional schemes, the source can transmit to the destination belonging to own cell coverage. In the proposed scheme, the destination can receive the additional signal from another base station through multiple relays. Therefore, the proposed scheme provides higher diversity gain and better performance than the conventional scheme. [ABSTRACT FROM AUTHOR]

Sanitary sewer systems are major infrastructures in every modern city, which are essential in protecting water pollution and preventing urban waterlogging. Since the conditions of sewer systems continuously deteriorate over time due to various defects and extrinsic factors, early intervention in the defects is necessary to prolong the service life of the pipelines. However, prior works for defect inspection are limited by accuracy, efficiency, and economic cost. In addition, the current loss functions in object detection approaches are unable to handle the imbalanced data well. To address the above drawbacks, this paper proposes an automatic defect detection framework that accurately identifies and localizes eight types of defects in closed‐circuit television videos based on a deep neural network. First, an effective attention module is introduced and used in the backbone of the detector for better feature extraction. Then, a novel feature fusion mechanism is presented in the neck to alleviate the problem of feature dilution. After that, an efficient loss function that can reasonably adjust the weight of training samples is proposed to tackle the imbalanced data problem. Also, a publicly available dataset is provided for defect detection tasks. The proposed detection framework is robust against the imbalanced data and achieves a state‐of‐the‐art mean average precision of 73.4%, which is potentially applied in realistic sewer defect inspections. [ABSTRACT FROM AUTHOR]

A wireless body area network (WBAN) is a radio-frequency-based wireless communication technology that consists of a number of different sensor and actuator nodes interconnected with a body gateway. Considering the constrained resources in WBAN devices, simple and noise-robust synchronization algorithms are required. Frame synchronization and frequency offset estimation are extremely important in the design of a robust WBAN receiver. In this paper, a detection strategy such as frame synchronization and frequency estimation is described in the WBAN system, which can improve the receiver performance. In doing so, algorithms are designed or chosen for the frame detection, carrier frequency offset synchronization, and joint fine-time and phase-offset estimation by exploiting the spike-like property of the physical layer convergence protocol preamble and the frame structure in the WBAN system. The performance of the WBAN synchronization receiver is verified by computer simulation. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

An adaptive precoding scheme with efficient joint processing (JP) is proposed for the downlink coordinated multi‐point transmission system. This scheme selects one JP technique and one precoding technique according to channel state information from the user equipment. The system‐level simulation results show that the bit error rate performance of the proposed scheme is better than that of the conventional scheme. [ABSTRACT FROM AUTHOR]