A comprehensive survey of TDD-based mobile communication systems from TD-SCDMA 3G to TD-LTE(A) 4G and 5G directions

TDD (Time Division Duplex) is one of the two duplex modes. TD-SCDMA (Time Division Synchronous CDMA) is the first TDD-based cellular mobile system which is commercialized in wide area and large scale and TD-SCDMA is also the first cellular mobile system which adopted smart antenna technology (also called as beamforming). As the long term evolution of TD-SCDMA, TD-LTE(A) (Time Division-Long Term Evolution, and TD-LTE Advanced) introduced OFDM (Orthogonal Frequency Division Multiplexing) and enhanced smart antenna technology together with MIMO (Multiple Input Multiple Output), which are adopted by LTE FDD (Frequency Division Duplex) either.

It is indicated that TD-SCDMA and TD-LTE(A) have opened a sustainable utilization era of TDD and smart antenna technologies in the wireless mobile communication. This paper aims to present a systematic introduction to TDD-based mobile communications from TD-SCDMA to TD-LTE and beyond, with particular focuses on TDD key technologies, principles of TDD cellular mobile systems, TDD evolution path, and future TDD 5G directions. The comparisons between TDD and FDD are also included. We hope that this paper will provide a comprehensive overview of TDD technology upgrade and its standard evolution, and serve as a valuable reference for research on 5G mobile communicationsystems. It is believed that TDD will play more important role in 5G.

OPART: Towards an Open Platform for Abstraction of real-time communication in cross-domain applications

Developing real-time communication in various application fields such as robotics, factory automation, etc. is one the most important steps achieving a deterministic system. However, the development of this step is very complex and requires low level and advanced knowledge about the real-timecommunication systems. This complexity decelerates the developing process specially in cross-domain applications e.g. surgical control applications in Networked Medical Systems (NMS) requiring real-time communication and deterministic system behavior.

General complexities developing real-timecommunication systems are classified. The architecture of an Open Platform for Abstraction of Real-Time Communication (OPART) is introduced for reducing these complexities. The architecture of OPART is based on the Ethernet-based real-time communication protocol openPOWERLINK. An experimental setup of OPART using a medical sensor and actuator is demonstrated.

Capacity and Bandwidth Analysis of Symmetric Two-Coil Resonant Magnetic Communication Using Frequency Divarication

In this letter, a novel two-coil magnetic communication method based on magnetic resonant coupling and frequency divarication is proposed. The half-power decay is employed to derive the boundary condition of double 3-dB bandwidths. Moreover, the expressions of load power, power ratio, andcommunication capacity are deduced based on the mutual inductance theory.

The theory proves that there exists one common peak value for the bandwidth and communication capacity. Also, the expression of peak value of the maximum capacity is derived using the boundary condition. The experimental results demonstrate that the proposed magnetic communication method has a maximum bandwidth and communication capacity at a wide frequency range, especially at low frequency.

Recent trends in multicarrier underwater acoustic communications

Underwater acoustic communication is essential in applications like remote control in the offshore oil industry, pollution monitoring in environmental systems, collection of scientific data recorded at ocean-bottom stations, disaster detection and early warning and underwater surveillance. Research on underwater wireless communication techniques plays a vital role in further exploring oceans and other marine environments. There has been an extensive growth in the volume of literature for underwater acoustic (UWA) communication but still it remains to be one of the most challenging areas of wirelesscommunication.

Over the years attention has turned on applying modified versions of multicarrier (MC)communication to underwater channel. This paper reviews the recent developments in the area of UWAcommunication related to multicarrier communication and particularly to orthogonal frequency division multiplexing (OFDM) with respect to applied, theoretical and simulation studies. An attempt has been made to present a compact yet exhaustive literature survey that will serve as a standard reference for researchers working in the area. Stress has been laid on the physical layer issues as it works as the basic foundation of any network. The focus areas of research activities have been identified and a summary of the ongoing activities and future trends has been presented.

Secure communication system for wearable devices wireless intra body communication

This paper explains how intra-body communication can be used to establish a secure communicationchannel for wearable devices. Intra-body communication transfers data using the human body as its conductor. This paper describes a secure communication system that supports multiple wearable slave devices.

Our prototype, wearable on the wrist, has an integrated processor to control the intra-bodycommunication module. Instead of using radio transmission, the module uses the human body, thus maximizing the security of transmitted signals.

A platform for converged, feature-based real-time communications

We propose in this paper a platform enabling advanced real-time communication (RTC) services in a very unified manner. Audio/video RTC is converged with other (not necessarily real-time) information and in-/output from users to create a new, richer communication experiences. More concrete, the proposed platform is capable of tailoring audio/video communication streams to converge their real-time payload with supplemental associated data exchange as images, overlay information, maps or texts. Such converged rich and interactive communication services can be provided either for managed Telecom networks with the IP Multimedia Subsystem (IMS) by using the platform as an Application Server, or over the global Internet for browser-based WebRTC User Agents.

The platform scales elastically according to different signaling and media processing load requirements. Problems addressed in our work are (1) platform requirements for converging real-tine multi media/protocolcommunication services and (2) its extensibility and scalability.

An Analysis of Machine-Type-Communication on Human-Type-Communication over Wireless Communication Networks

With the advent of new wireless technologies, it is expected that the use of Machine-TypeCommunication (MTC)will significantly increase in next generation wireless networks. Wirelesscommunication networks are considered to support due to their availability and existing infrastructures. As these networks are designed and optimized in a way that they fit best for Human TypeCommunication (HTC), there is a need of an efficient radio resource management (RRM)to accommodate MTC traffic without affecting the regular HTC traffic in the network.

In this paper, a continuous-time Markov chain (CTMC) model-based RRM scheme is proposed to analyze the impact of MTC on HTC traffic in wireless communication networks, in terms of blocking probability and channel utilization. Numerical results are given, showing the effectiveness of the proposed RRM scheme in providing the quality of service isolation between HTC and MTC traffic.

Secure communication scheme for wireless sensor networks to maintain anonymity

In wireless sensor networks it is becoming more and more important for sensor nodes to maintain anonymity while communicating data because of security reasons. Anonymous communication among sensor nodes is important, because sensor nodes want to conceal their identities either being a base station or being a source node. Anonymous communication in wireless sensor networks includes numerous important aspects, for instance base station anonymity, communication association anonymity, and source node anonymity. From the literature, we can observe that existing anonymity schemes for wireless sensor networks either cannot realize the complete anonymities, or they are suffering from various overheads such as enormous memory usage, complex computation, and longcommunications.

This paper is presenting an efficient secure anonymity communication protocol (SACP) for wireless sensor networks that can realize complete anonymities offering minimal overheads with respect to storage, computation and communication costs. The given secure anonymitycommunication protocol is compared with various existing anonymity protocols, and the performance analysis shows that our protocol accomplishes all three anonymities: sender node anonymity, base station anonymity, and communication association anonymity while using little memory, lowcommunication cost, and small computation costs.

Communication Optimization of Iterative Sparse Matrix-Vector Multiply on GPUs and FPGAs

Trading communication with redundant computation can increase the silicon efficiency of FPGAs and GPUs in accelerating communication-bound sparse iterative solvers. While k iterations of the iterative solver can be unrolled to provide O(k) reduction in communication cost, the extent of this unrolling depends on the underlying architecture, its memory model, and the growth in redundant computation. This paper presents a systematic procedure to select this algorithmic parameter k, which providescommunication-computation tradeoff on hardware accelerators like FPGA and GPU. We provide predictive models to understand this tradeoff and show how careful selection of k can lead to performance improvement that otherwise demands significant increase in memory bandwidth.

On an Nvidia C2050 GPU, we demonstrate a 1.9×-42.6× speedup over standard iterative solvers for a range of benchmarks and that this speedup is limited by the growth in redundant computation. In contrast, for FPGAs, we present an architecture-aware algorithm that limits off-chip communication but allowscommunication between the processing cores. This reduces redundant computation and allows large k and hence higher speedups. Our approach for FPGA provides a 0.3×-4.4× speedup over same-generation GPU devices where k is picked carefully for both architectures for a range of benchmarks.

Power and Rate Optimization for Visible Light Communication System With Lighting Constraints

Visible-light communication (VLC) will be deployed in various indoor environments, including those requiring different lighting colors, which imposes the needs for transmission optimization under certain lighting constraints. This work establishes a framework for the transmission power and rate optimization, for light emitting diode (LED)-based VLC systems under lighting constraints. We describe the system model of LED-based color-division VLC system, which incorporates the transmission power spectral density, the receiving optical filters, the human eye perception, and the lighting constraints. Then, we formulate the corresponding power and rate optimization problems, for both point-to-pointcommunication system and broadcast communication system.

More specifically, for a point-to-pointcommunication system, it maximizes the transmission rate subject to the transmission power constraint and the lighting constraint; and for a broadcast system, it minimizes the total transmission power subject to some quality of service (QoS) constraint across all receivers. Various convex optimization problems have been formulated and solved analytically or using standard convex optimization solutions. It is obsesrved that the optimal symbol modulation power allocation scheme significantly outperforms the equal power allocation scheme.