Nam Tuan Le

Asynchronous scheme for optical camera communication-based infrastructure-to-vehicle communication

This paper introduces infrastructure-to-vehicle (I2V) communication based on asynchronous optical camera communication (OCC), the transmitter of which can be an LED traffic light or electronic display, with the receiver being the existing front vehicle camera. In asynchronous OCC-based I2V communication, the key technique is an asynchronous scheme. An asynchronous scheme not only takes advantage of simplicity owing to the lack of an uplink or synchronization requirement, but is also the most feasible solution for communication to/from moving vehicles where synchronization is difficult to achieve within a short time. An asynchronous scheme for OCC-based I2V communication is proposed, and a performance evaluation shows its feasibility for use in a number of promising OCC-based wireless communication applications and services in a vehicular environment.

High-speed asynchronous Optical Camera Communication using LED and rolling shutter camera

This paper introduces the asynchronous Optical Camera Communication (asynchronous OCC) using LED and rolling shutter camera as a pair of wireless communication. Aiming to enhance the capacity of unidirectional wireless link, the response of camera is measured, and then the operating frequency range, system architecture, decoding procedure and algorithm are proposed. The frame and super-frame structure are also considered especially for OCC using rolling shutter camera. The performance of implemented system is evaluated and discussed.

Practical design of Screen-to-Camera based Optical Camera Communication

This paper introduces the Optical Camera Communication (OCC) based on Computer Vision. The practical issues of implementation of the asynchronous communication based Screen-to-Camera are performed. The asynchronous scheme proposed by our previous work is modified to be simple, suitable and reliable in order to apply in case of heterogeneous frame rate of camera. In addition, the design of multi LEDs transmitter together with image processing technique are also proposed to mitigate perspective distortion in real-time LEDs detection and multi colors decoding achieving high performance.

Energy-Efficient coverage guarantees scheduling and routing strategy for wireless sensor networks

With the development of semiconductors and the resulting effect on manufacturing costs, wireless interface platforms have become increasingly powerful and popular. This has resulted in widespread applications ranging from daily life activities to military services. In large-scale applications of wireless sensor networks such as military surveillance, there are two important issues that determine the success of network services. The first is sensing coverage, the data collection process from the target that directly affects network traffic. The second is network lifetime which is based on the optimization of energy consumption. Power optimization for mobile platforms can be classified into two categories: efficient power based on protocol and extended interface. In this paper, we suggest an energy model for wireless sensor networks that is based on the first issue; it can be called Coverage and Energy Strategy for wireless sensor networks (CESS). The scheme will attempt to achieve optimal coverage of the sensing area and energy balanced scheduling for all sensors. It can reduce redundancy of working sensor nodes by defining minimal number of active nodes in a sensing area. Thus the network lifetime will be maximized by reducing redundancy power consumption.

Survey of Promising Technologies for 5G Networks

As an enhancement of cellular networks, the future-generation 5G network can be considered an ultra-high-speed technology. The proposed 5G network might include all types of advanced dominant technologies to provide remarkable services. Consequently, new architectures and service management schemes for different applications of the emerging technologies need to be recommended to solve issues related to data traffic capacity, high data rate, and reliability for ensuring QoS. Cloud computing, Internet of things (IoT), and software-defined networking (SDN) have become some of the core technologies for the 5G network. Cloud-based services provide flexible and efficient solutions for information and communications technology by reducing the cost of investing in and managing information technology infrastructure. In terms of functionality, SDN is a promising architecture that decouples control planes and data planes to support programmability, adaptability, and flexibility in ever-changing network architectures. However, IoT combines cloud computing and SDN to achieve greater productivity for evolving technologies in 5G by facilitating interaction between the physical and human world. The major objective of this study provides a lawless vision on comprehensive works related to enabling technologies for the next generation of mobile systems and networks, mainly focusing on 5G mobile communications.

Neural Network-Based Indoor Positioning Using Virtual Projective Invariants

Indoor positioning techniques has become a key research issue for future smart services because of the high market value in providing location-based services via smartphones and ondemand services. In image sensor communications (ISC) case, one of the main advantages of the indoor navigation system is that the LED itself can transmit its location information using visible light communication. In addition, the camera usually has an angle of arrival sensor that facilitates the precise determination of not only user position but also user orientation. However, because of the nonlinear and highly complicated relationship between 3D scenery and a pictured 2D image, the development of a complex mathematical model is needed to estimate user position using a camera. Neural network is a good approach for minimizing this complicated relationship. Hence, it is possible to develop a precise positioning technique without any complicated mathematical model between the 3D world and 2D image coordinates. This paper proposes a neural network-based novel positioning technique. The proposed method exploits the projective invariant properties of a line that is virtually constructed with the help of ISC. Then, a neural network scheme is used to extract the camera orientation information from that virtual line. Next, a simple mathematical equation is used to estimate user position. Simulation results show the proposed method has better performance than the previous methods.

Approximate queuing analysis for IEEE 802.15.4 sensor network

Wireless sensor networks (WSNs) have attracted much attention in recent years for their unique characteristics and wide use in many different applications. Especially, in military networks, all sensor motes are deployed randomly and densely. How can we optimize the number of deployed nodes (sensor node and sink) with a QoS guarantee (minimal end-to-end delay and packet drop)? In this paper, using the M/M/1 queuing model we propose a deployment optimization model for non-beacon-mode 802.15.4 sensor networks. The simulation results show that the proposed model is a promising approach for deploying the sensor network.

A New QoS Resource Allocation Scheme Using GTS for WPANs

IEEE 802.15.4 (for low-rate Wireless Personal Area Networks—WPANs) (IEEE 802.15.4 Standard-2003) and IEEE 802.15.7 (for Short-Range Wireless Optical Communication Using Visible Light) (IEEE 802.15.7 Standard—2011) are two typical standards for WPANs that support Quality-of-Service (QoS) through a Guaranteed Time Slot (GTS) mechanism to allocate a specific duration within a superframe structure for a time division multiplexing transmission. The low bandwidth utilization problem may occur in the GTS mechanism when the allocated bandwidth is less than the available bandwidth. However, this problem has not been resolved thoroughly in any of the standard or current research thus far. This paper analyzes GTS performance in QoS-guaranteed transmission and proposes a new GTS allocation scheme named Unbalanced GTS Allocation Scheme (UGAS), which improves the bandwidth resource efficiency. Our scheme tries to solve the bandwidth under-utilization problem by using Network Calculus theory based on the fluid model and greedy algorithm. The UGAS scheme divides the Contention-Free Period into time slots of different durations to support various bandwidth requirements. Time slots are allocated using an approximation QoS model to minimize under-utilization. Compared with the standard GTS allocation scheme, UGAS makes an efficient bandwidth allocation with the QoS-guaranteed model and without breaking the standard protocol. The numerical results show that the average bandwidth utilization using UGAS can be improved by 30 % as compared with the standard scheme.

Effect of blur Gaussian in MIMO optical camera communications

MIMO is popular technique which can improve the reliability and spectral efficiency of RF communication system by using the spatial link dimensions. It is also an attractive option solution for achieving high data rate. Optical Camera Communication (OCC) is considered for revision specification of visible light communication standard. One of the most consideration disadvantages of OCC is data rate limitation. With traditional modulation scheme, the throughput can achieve a few bits per second. MIMO is promising technique to overcome this limitation. Independent streams of light transmitter array will be sent over optical channel and decoded over a group of camera pixels. However with the effect of blur, two transmit element images may not be resolvable by overlap pixels. In this paper we analyze and evaluate the performance of the blur Gaussian in MIMO OCC.

Smart color channel allocation for visible light communication cell ID

In wireless communication network, multi-channel communication technology is a promising solution for throughput performance enhancement and collision avoidance. Similarly with visible light communication, multi-channel approach will show more advances due to the limitation of color channel and co-channel interference at the photo detector. In this research, we proposed a new color channel allocation for visible light communication Cell ID based on IEEE 802.15.7 specification. The proposed scheme is based on feedback channel information, channel priority and cognitive technique. We hope that with the flexibility, efficiency, and reliable scheduling of cognitive issue, it proves to a promising technology for future wireless network generally and especially visible light communication. The numerical results and experimental implementation show the enhancement of signal-to-noise ratio, blocking probability, and CCA time.