Data Rate Wireless Networks Research Articles

Joint User Clustering and Beamforming in Non-Orthogonal Multiple Access Networks

The demand for higher data rate in wireless networks continues to grow, however the wireless spectrum cannot meet ever-increasing demands. Non-orthogonal Multiple Access (NOMA) technology is attracting attentions to overcome the lack of resource spectrum and increase spatial reuse. Traditionally, data is delivered in an orthogonal fashion in the frequency or time domain, whereas NOMA leverages power domain to improve spectral reuse. User clustering is one of the key features that significantly affects NOMA's throughput performance and fairness among the users in the network. In addition to NOMA, beamforming increases spectral efficiency by improving SNR for specific users (and groups) and reducing interference across the clusters. However, combining beamforming with NOMA is a challenging and complex problem because beamforming for improving the reuse of spectral resources is tightly coupled with user clustering in NOMA. In this paper, we introduce a joint user clustering and beamforming scheme that maximizes the network throughput in NOMA with beamforming. Toward this goal, we carefully analyze several features that significantly affect the system throughput and design a heuristic algorithm based on the inferences. Our algorithm increase the signal power in NOMA and effectively reduce both beamforming and NOMA interference. Evaluation results reveal that our solution provide higher utility (sum rate) than other existing schemes and significantly improve fairness among users regardless of the channel conditions.

Power Control Based Multiuser Full-Duplex MAC Protocol for the Next Generation Wireless Networks

Continuously increasing the data rate in wireless networks is required to satisfy the ever-increasing service demands. Full-duplex (FD), a promising technology for wireless networks, is able to double the data rate theoretically. Although several researchers study the physical (PHY) and medium access control (MAC) protocols of FD technology, there are few study focusing on the multiuser MAC protocol design for the next generation wireless networks. In this paper, a power control (PC) based multiuser FD MAC protocol, named PC MU-FuPlex, is proposed. Moreover, the probability of establishing FD link is formulated specifically. The simulation results demonstrate that the proposed MAC protocol significantly improves the saturation throughput up to 200% compared to that without PC in higher modulation.

High-throughput low-delay MAC protocol for TeraHertz ultra-high data-rate wireless networks

To address the problems of the present TeraHertz medium access control (MAC) protocols such as not updating the time slot requests numbers in time, unreasonable superframe structures and not merging time slot requests from the same pair of nodes, high throughput low delay medium access control (HLMAC), a novel MAC protocol for TeraHertz ultra-high data-rate wireless networks is proposed. It reduces the data access delay largely with a new superframe structure, from which nodes can get time slot allocation information immediately. The network throughput is also improved with the help of updating time slot requests number and merging time slot requests from the same pair of nodes. The theoretical analysis verifies the effectiveness of HLMAC, and the simulation results show that HLMAC improves the network throughput by 65.7% and decreases the access delay by 30%, as compared to energy and spectrum-aware medium access control (ES-MAC).

A Multilayer LTCC Solution for Integrating 5G Access Point Antenna Modules

An integrated solution for the development of multilayer antenna modules for fifth-generation (5G) communications, based on low temperature cofired ceramic (LTCC), is presented. The design exploits the 3-D integration capabilities of the LTCC process, enabling the realization of a full-corporate feed network (CFN) in vertical configuration. A novel implementation of the CFN employing dielectric-embedded parallel plate waveguides (PPWs) is proposed. The PPW lines are delimited by via-rows. As opposed to standard substrate-integrated waveguide feed networks, guided fields are orthogonal to the via-rows and propagate along the vertical axis of the structure. The CFN feeds four long slots, without any coupling structure, and provides broadband operation. The final prototype comprises 18 LTCC tapes, with a total thickness of 3.4 mm. The measured −10-dB impedance bandwidth spans from 51.2 to 66 GHz (>25.2%). The module generates a fixed broadside beam, but multibeam operation in $H$ -plane can be easily achieved. In the 50–66-GHz band, the peak gain is 14.25 dBi and the average first side-lobe level in $H$ -plane is −20.6 dB. The proposed technology and the design concept are suited for highly integrated millimeter-wave systems, such as access points in the future $V$ -band high data-rate wireless networks.

Decentralized Learning-Based Relay Assignment for Cooperative Communications

Cooperative communication exploits spatial diversity via relay node antennas to increase data rates in wireless networks. Relay node selection, therefore, plays a critical role in system performance. This paper examines the problem of relay node selection in cooperative networks, in which one relay node can be used by multiple source–destination transmission pairs, and all transmission pairs share the same set of relay nodes. Centralized approaches may exhibit higher complexity when the number of source nodes is increased. This paper gives source nodes self-optimizing and self-learning abilities and enables them to autonomously select relay nodes. A fully distributed approach, called a “Decentralized Learning-based Relay Assignment” (DLRA) algorithm, is proposed to achieve this goal. DLRA uses a reinforcement learning technique called stochastic learning automata, with each source node attaining the self-learning ability to find an appropriate relay node according to environmental feedback. This paper shows the convergency, optimality, and performance of DLRA via mathematical analysis and evaluates the performance of DLRA in two different network systems: a cooperative ad hoc network and a Long-Term Evolution (LTE)-Advanced relay network. The experimental results present several properties of DLRA: the effectiveness of DLRA in cooperative communication systems, the significant improvements made by DLRA in fairness, and the capacity of each node in LTE-Advanced systems.

A Cloud-Based Architecture for the Internet of Spectrum Devices Over Future Wireless Networks

The dramatic increase in data rates in wireless networks has caused radio spectrum usage to be an essential and critical issue. Spectrum sharing is widely recognized as an affordable, near-term method to address this issue. This paper first characterizes the new features of spectrum sharing in future wireless networks, including heterogeneity in sharing bands, diversity in sharing patterns, crowd intelligence in sharing devices, and hyperdensification in sharing networks. Then, to harness the benefits of these unique features and promote a vision of spectrum without bounds and networks without borders, this paper introduces a new concept of the Internet of spectrum devices (IoSDs) and develops a cloud-based architecture for IoSD over future wireless networks, with the prime aim of building a bridging network among various spectrum monitoring devices and massive spectrum utilization devices, and enabling a highly efficient spectrum sharing and management paradigm for future wireless networks. Furthermore, this paper presents a systematic tutorial on the key enabling techniques of the IoSD, including big spectrum data analytics, hierarchal spectrum resource optimization, and quality of experience-oriented spectrum service evaluation. In addition, the unresolved research issues are also presented.

ZigBee Network Routing Algorithm Based on the Research

ZigBee is the new standard that has been developed for low cost, low data rate and low power consumption wireless network,The routing algorithm is the key of the research and development work. This paper introduces the ZigBee protocol model of specification, And focuses on the ZigBee protocol network layer routing algorithm, Analyzes the advantages and disadvantages of tree routing and AODVjr routing algorithm.

Novel MAC protocol for terahertz ultra-high data-rate wireless networks

Due to having a large bandwidth to support Gbps-level data rate, terahertz communication attracts more and more attention in recent years. However, there are few medium access control (MAC) protocols for terahertz ultra-high data-rate wireless networks, which affects the research and application of terahertz communications. To address this problem and to achieve ultra-high data-rate wireless access with terahertz communication, a novel MAC protocol, called medium access control for terahertz communication (MAC-TC), is proposed. Through designing a new channel access scheme, a new superframe structure, and related key parameters, MAC-TC can support a maximum data rate up to 10 Gbit/s even higher. Theoretical analysis and simulation results show that our proposed MAC protocol realizes the function of medium access control and attains a maximum data rate of 18.3 Gbit/s, which is 2 times higher than 5.78 Gbit/s, the theoretical maximum data rate of IEEE 802.15.3c standard.

New medium access control protocol of terahertz ultra-high data-rate wireless network

New medium access control protocol of terahertz ultra-high data-rate wireless network

A MAC Protocol for Terahertz Ultra-High Data-Rate Wireless Networks

The terahertz wave is a kind of electromagnetic waves which locates between millimeter waves and infrared lightwaves, and the frequency range is 0.14THz~10THz. Terahertz is used as a carrier wave to communicate with each other because it has large bandwidth which can support Gbps wireless data rates. Therefore, terahertz communication technologies become research hot spots in recent years. However, its still rare in MAC protocol of terahertz ultra-high data-rate wireless networks at present. In order to realize wireless access of ultra-high data-rate under the condition of terahertz carrier frequency, a novel MAC protocol is proposed in this paper. The improved MAC protocol which makes the maximum data rates reach up to 10Gbps or higher is designed by new MAC control mechanisms, new time-slots allocation schemes and new superframe structure. Theoretical analysis and simulation results show that the new proposed MAC protocol of terahertz ultra-high data-rate wireless networks can operation normally, and the maximum data rate can reach up to 19.2Gbps. This maximum data rate is 2 times higher than 5.78 Gbps which IEEE 802.15.3c can achieve.

Distributed Lifetime and Data Rate Optimization with Dynamic Approximation in Wireless Networks

In this paper, we study the problem of jointly maximizing network lifetime and data rate in wireless networks. For this problem, we introduce a general network utility maximization (NUM) cross-layer formulation that accommodates routing, scheduling and stream control from different layers of network with relevant constraints. In particular, based on both Lagrangian approach and Markov Chain Monte Carlo method, we extend our programming model to distributed algorithms that can dynamically approximate the optimal solution to this problem. Finally, we present computational results for the insight that can be gained from the cross-layer optimization and the distributed algorithms.

Multi Agent System based TCP for Wireless Networks

to the rapid evolution of networking and electronic capabilities, the use of wireless devices is becoming ubiquitous. Most of the wireless networks have fixed infrastructure and requires higher data rates. Due to high data rate in wireless networks the Transmission Control Protocol (TCP) performance has a broad and significant impact on data applications, and is essential towards massive deployment of service-providing agents and their widespread social acceptance. Wireless link losses result in poor TCP throughput since losses are professed as congestion by TCP. In order to increase the throughput, a Multi agent System (MAS) named Reusable Environment for Task-Structured Intelligent Networked Agents (RETSINA) has been introduced. This agent has the capability to reduce the impact of losses on TCP throughput and latency. In this work, we considered a video game application in which a networked virtual environment with high fidelity sound and video is created. Moreover, to efficiently use the video game application in a wireless environment, an Unreal Tournament Semi-Automated Force (UTSAF) multi agent has been proposed. UTSAF is a middleware written to take advantage of the power of gaming application systems by allowing them to participate in distributed simulations. The personal agent communicates wirelessly, in order to find the most appropriate option to serve the user. In addition, we comprehensively evaluated the performance of TCP with and without these multi agent platforms as technology choice and investigated its efficiency in a number of cases. We find that the simulations with the multi agent can reach the TCP throughput by as much as 95 % and the latency get reduced by 1-2 % as the simulation time steps in for every 100 seconds.

An Optimal Algorithm for Relay Node Assignment in Cooperative Ad Hoc Networks

Recently, cooperative communications, in the form of having each node equipped with a single antenna and exploit spatial diversity via some relay node's antenna, is shown to be a promising approach to increase data rates in wireless networks. Under this communication paradigm, the choice of a relay node (among a set of available relay nodes) is critical in the overall network performance. In this paper, we study the relay node assignment problem in a cooperative ad hoc network environment, where multiple source-destination pairs compete for the same pool of relay nodes in the network. Our objective is to assign the available relay nodes to different source-destination pairs so as to maximize the minimum data rate among all pairs. The main contribution of this paper is the development of an optimal polynomial time algorithm, called ORA, that achieves this objective. A novel idea in this algorithm is a “linear marking” mechanism, which maintains linear complexity of each iteration. We give a formal proof of optimality for ORA and use numerical results to demonstrate its capability.

A resource allocation strategy for meshed high data rate WPANs

In order to extend the operating space of single hop High Data Rate (HDR) Wireless Personal Area Networks (WPANs), the meshed configuration can be used for multi-hop functionality. Since the superframe is shared between multiple WPAN piconets for communication, with higher device density, the superframe capacity usually proves to be a bottleneck. Furthermore, when the superframe capacity is shared in a distributed fashion, issues of fairness in time allocation arises. In this paper we propose a centralized scheme for resource allocation specifically in meshed WPANs and induce an element of fairness in time allocation. Simulation results prove the effectiveness of the proposed approach.

A two-level medium access framework for exploiting multi-user diversity in multi-rate IEEE 802.11 wireless LANs

Fast rate adaptation has long been recognized as an effective way to improve the PHY-layer data rate of wireless networks. However, in random access wireless networks such as IEEE 802.11 wireless LANs, MAC-layer throughput is dominated by stations with the lowest transmission rates, resulting in an underutilization of spectrum bandwidth. In this paper, we propose a novel two-level medium access framework, referred to as two-level MAC, to solve the aforementioned problem and to significantly improve system spectrum efficiency through the exploitation of multiuser diversity. The key idea of two-Level MAC is to introduce a second level of deterministic channel access on top of the traditional IEEE 802.11 DCF protocol. By doing so, higher priority is granted to high-rate stations in a fully distributed manner. Meanwhile, collisions among potential contending stations are drastically reduced. Through analysis, we show how such two-Level MAC can be optimized to achieve the maximum system throughput. The superiority of the proposed protocol is verified through analyses and extensive simulations.

Performance evaluation of a Radio over Fiber (ROF) system subject to the transmitter's limitations for application in broadband networks

The increasing demand for high data rates in wireless networks indicates radio-over-fiber (RoF) as an excellent candidate for physical layer infrastructure in the development of future broadband communication systems. In this work, a thorough investigation on the performance of an intensity-modulation direct detection (IM-DD) RoF system utilizing orthogonal frequency division multiplexing (OFDM) is performed, emphasizing on the transmitter's impairments, and to what extend the above limitations are compensated by typical demodulation techniques implied in OFDM technology. It is shown that an acceptable performance is depicted up to 5.8 GHz carrier frequency, by a proper adjustment of the laser's current RF amplitude level.

Frequency-Time Block Code for frequency diversity in UWB-OFDM systems

The Ultra-WideBand Orthogonal Frequency Division Multiplexing (UWB-OFDM) approach is a promising physical-layer technique for short-range, high data-rate wireless networks. As the occupied band-width increases, however, its implementation becomes more and more difficult. In order to make it easier to achieve a UWB-OFDM system, a complexity-reduced Frequency diversity (F-diversity) scheme, Frequency-Time Block Code (FTBC), is presented in this paper. The FTBC halves the sampling rate required by other F-diversity techniques so as to cut down the cost of UWB-OFDM systems with F-diversity to a certain extent.

A high-performance MIMO OFDM wireless LAN

Tremendous consumer interest in multimedia applications is fueling the need for successively higher data rates in wireless networks. Data rates in wireless wide area networks are limited by the need to address wide coverage, vehicular mobility, and the limitations of licensed spectrum. Thus, data rates in WWANs continue to lag advances in wireless local area networks by orders of magnitude. There are valuable lessons to be learned from the design of WLANs that provide data rates in excess of hundreds of megabits per second. Several technologies are instrumental in enabling the future of high-performance WWANs, including multiple transmit and receive antennas, OFDM, closed loop transmission control, and low-latency MAC operation. We describe a MIMO WLAN design and prototype that exploits these attributes to provide data rates in excess of 200 Mb/s above the MAC

Feedforward control of data rate in wireless networks

This paper develops a feedforward approach to data-rate control in wireless networks. The development is based on designing an optimal but noncausal controller and its subsequent modification, which leads to a causal implementable suboptimal controller driven by an estimate of the bit-error probability. It is shown that this controller results in a minimum of 5%-85% increase in average throughput without additional power utilization, as compared with fixed data rate operation.