Wireless communication is a ubiquitous technology in our society, being present in a large variety of applications that in their progressive nature requires continuous improvements. Many technologies have been proposed to increase wireless network throughput and reduce the overall delay, such as multiple-input multiple-output (MIMO). The recent advances in wireless communication show the feasibility of a radio capable of concurrently transmitting and receiving data, i.e., in a full-duplex manner which has the potential to double the network throughput. This paper presents a novel full-duplex multi-user and multi-channel protocol that distinguishes from Full-Duplex Many-to-Many Multichannel MAC (FD-M2MMAC) [1] by employing a full-duplex radio with multi-user detection. We employed an analytical model in order to evaluate the protocol with previous related Many-to-Many Multichannel MAC (M2MMAC) [2] and FD-M2MMAC proposals. The mathematical results show that, by employing a combination of a full-duplex radio with V-BLAST (Vertical-Bell Laboratories Layered Space-Time) capability, the proposed protocol uses the Communication window more efficiently and it was able to increase the throughput up to 56% when compared with FD-M2MMAC, using 6 antennas, at the same time that it attains 50% increase in throughput when compared with M2MMAC.

Connected devices have increasingly become more popular in the recent decade and they are used in several applications each one provided with different requirements and limitations to wireless network design producing new challenges for medium access protocols. In this context, the multi-user protocols have become a popular approach to meet applications criteria. On the other hand, full-duplex wireless technology brings the expectation to double the overall throughput. This work proposes a new wireless MAC protocol based on M2MMAC [1], [2], a many-to-many protocol based on IEEE 802.11 PSM [3] intended for ad hoc networks. The proposed protocol uses self-interference cancellation to achieve full-duplex communication combined with OFDMA. An analytical model is presented in order to evaluate the aggregated saturation throughput. We compare both protocols, varying the number of channels, antennas, and the duration of the Announcement Traffic Indication MAP (ATIM) window, and the results show that the full-duplex communication was able to improve up to 50% the throughput.

The algorithms commonly used for energy control in systems with Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol involve optimization functions with considerable computational complexity and need rigorous control of the test environment. These restrictions create a gap among design, theoretical analysis, real-time processing of network devices and the dependence on human support for parameters setting. In this paper, we propose a novel approach to reach energy saving based on machine learning which considers the input and output of a power consumption control algorithm in CSMA networks, taking into account multiple physical (PHY) layer variables. The results show that the proposed approach obtained a better performance regarding processing time, computational cost and self-adaptation of the parameters currently defined by greedy search energy control algorithms.

Motivated by the need to accommodate IoT devices that have limited power, processing, storage, and communication capabilities, this work introduces IoTUS, or IoT Unified Services (IoTUS), a novel network protocol architecture that targets energy efficiency and compact memory footprint. IoTUS uses an extensible service layer that facilitates cross-layer sharing. It promotes sharing of both network control information, (e.g., number of transmissions, receptions, collisions at the data-link layer) and functionality (e.g., neighbor discovery, aggregation) by different layers of the protocol stack. Additionally, IoTUS can be used by existing network stacks without having to modify the basic operation of their protocols. We implemented IoTUS on the Cooja-Contiki network simulator/emulator. Our experimental results show improved energy efficiency resulting in longer network lifetime, as well as more compact memory footprint resulting when compared to current IoT protocol architectures.

This paper presents a new approach for Active Queue Management (AQM) techniques and TCP networks called Explicit Non-Congestion Notification (ENCN) whose performance is compared with Random Early Detection (RED), Controlled Delay (CoDel), and Proportional Integral controller Enhanced (PIE) schemes. The techniques were modeled and evaluated for TCP-Reno and TCP with selective acknowledgment (Sack) protocols. In addition, modeling and simulation of the TCP network and the AQM schemes were attained through formalities of discrete event and hybrid automata systems using the UPPAAL tool. Simulation results show that ENCN outperforms RED, CoDel, and PIE techniques in terms of throughput, fairness, and queue length stability in benchmark network topologies like daisy-chain and dumbbell scenarios.

To study dynamic aspects of network protocols, like the transmission network protocol TCP, and networked control systems (NCS) with a UDP-like flow in a single framework, we employed UPPAAL, a tool that simulates discrete event systems as switched automata. Delays and packet losses can degrade the performance of a control loop, leading in the worst case to instability. In opposition to standard communication tasks, the data throughput is not so relevant for the control task - the quality of control (here measured by the ITAE criterion) is adopted in this paper. We focus on processes controlled over standard Internet. First, we present a simulation of TCP-Reno protocol modeled through formalities for discrete event and timed automata systems using UPPAAL. Results were compared with simulations in the NS-2 simulator found in literature. Over this TCP-Reno model we added a control system over the network, where we can observe and study how the communication network affect control performance behavior for different simulation scenarios and with different Active Queue Management (AQM) techniques. In addition, in order to improve the tradeoff between TCP-throughput and control system performance we present a new AQM technique called Explicit Non-Congestion Notification (ENCN) whose performance is compared with Random Early Detection (RED), Control Delay (CoDel) and Proportional Integral controller Enhanced (PIE) schemes. According to our study, CoDel queue policy gives us the best control performance but worsens the TCP throughput; however, as an expected compromise, the ENCN give us better tradeoff between control performance and TCP throughput.

This paper investigates multi-hop wireless ALOHA ad hoc networks evaluating the bit error rate (BER). It is proposed an alteration of the Friis propagation model which allows its application to any node density with random network topology and obeys the law of conservation of energy. The results show that the adapted model appropriately describes the BER performance for dense networks. It was also verified that the increase of transmission power in dense networks without augment in transmission band does not improve the BER performance and it has importance to sensor networks in which energy consumption is crucial.

The present work investigates the behavior of the signal to noise and interference ratio (SNIR) and communication channel capacity of mobile ad hoc networks (MANETs) as a function of the number of nodes. From the propagation model that considers attenuation with the distance, a change was proposed such that, as the transmitter arbitrarily approximates to the receiver, the channel gain depends only on the fading, in order to have the received power not greater than the transmitted power; therefore, obeying the law of conservation of energy. Results were obtained analytically and by simulations and they show that the SNIR and capacity go to zero as the node density in the network increases for the path loss parameter α ≥ 2, indicating that communication among close neighbors is not feasible in such MANETs.

It has been recently shown that the instantaneous average node speed for the random waypoint (RWP) mobility model may not reach a steady state regime due to velocity gradual decaying which can cause inaccurate results in simulations and communication protocol validations for mobile ad hoc networks (MANETs). This paper presents a modification to the RWP model, in which we propose to choose node speeds from a BETA(2,2) distribution, demonstrating analytically and by simulations that our idea stabilizes the instantaneous average node speed and consequently other important network metrics, like control overhead, number of dropped data packets and delivery delay. The proposal of alteration not only eliminates the decaying problem of the average node speed but also provides average values closer to the commonly supposed average velocity (Vmax+ Vmin)/2 than those of the original RWP model. In addition, the proposed change for the RWP model can be readily incorporated into network simulators.

We introduce a collaboration-driven approach to the sharing of the available bandwidth in wireless ad hoc networks, which we call many-to-many communication, that allows concurrent multi-packet transmissions (MPTs) and multi-packet receptions (MPRs). Many-to-many communication also permits one-time multi-copy relaying of the same packet, which reduces the packet delivery delay compared to single-copy relaying without any penalty in capacity. Our scheme is based on the integration of multi-user detection and position-location information with frequency and code division in mobile ad hoc networks (MANETs). Transmissions are divided in frequency and codes according to node locations, and successive interference cancellation (SIC) is used at receivers to allow them to decode and use all transmissions from strong interfering sources. Consequently, the interference is divided into constructive interference (COI) and destructive interference (DEI). We show that, if each node is allowed to expand its bandwidth, both the link's Shannon capacity and the per source-destination throughput scale like O(nalpha/2) (upper-bound) and Omega[f(n)] (lower-bound), for n nodes in the network, a path loss parameter alpha > 2, and 1les f(n)alpha/2.

We introduce a collaboration-driven approach to the sharing of the available bandwidth in wireless ad hoc networks, which we call many-to-many cooperation, that allows concurrent many-to-many communication. This scheme is based on the integration of multi-user detection and position-location information with frequency and code division in mobile ad hoc networks (MANETs). Transmissions are divided in frequency and codes according to nodal locations, and successive interference cancellation (SIC) is used at receivers to allow them to decode and use all transmissions from strong interfering sources. Consequently, the interference is divided into constructive interference (COI) and destructive interference (DEI). We show that, if each node is allowed to expand its bandwidth, both the link's Shannon capacity and the per source-destination throughput scale likeO(nalpha/2) (upper-bound) and Omega[f(n)] (lower-bound), for n nodes in the network, a path loss parameter alpha > 2, and 1 les f(n)alpha/2. Many-to-many cooperation allows multi-copy relaying of the same packet, which reduces the packet delivery delay compared to single-copy relaying without any penalty in capacity.

We present interference analysis for wireless ad hoc networks and show that, depending on the path loss parameter ( ), the average signal to noise and interference ratio (SNIR) either remains constant, or decays, when the number of interferers scales to infinity in the network, for nodes communicating with their close neighbors. Thus, communication is feasible in dense networks as long as ≫ 2 and a node attempts to transmit to other nodes located close enough so that interference can be overcome. An analytical model for interference is described and Monte-Carlo simulations validate our results.

Multiuser diversity has been shown to increase the throughput of mobile ad hoc wireless networks (MANETs) when compared to fixed wireless networks. This paper addresses a multiuser diversity strategy that permits one of multiple one-time relays to deliver a packet to its destination. We show that the throughput of the original single one-time relay strategy is preserved by our multi-copy technique. The reason behind achieving the same asymptotic throughput is the fact that, as we demonstrate in this paper, interference for communicating among closest neighbors is bounded for different channel path losses, even when goes to infinity. We show that a significant delay reduction is possible by multi-copy relaying when is finite. Furthermore, we find that the average delay and delay variance for both the one and multi-copy relay strategies scale like and , respectively. We derive an approximation of the delay for multi-copy forwarding scheme and demonstrate that this approximation is very close to simulation results in MANET systems.

We introduce a new communication scheme for mobile wireless ad hoc networks (MANETs) utilizing the concept of cooperative many-to-many communication, called opportunistic cooperation1, as opposed to the traditional approach that emphasizes on point-to-point communication. In the new paradigm, the adjacent nodes no longer interfere with each other but rather cooperate. Our analysis is for MANETs when all the nodes in the network are endowed with M antennas. We derive two upper bounds on the ergodic capacity per node in the network. These upper bounds are compared with Monte-Carlo simulation of point-to-point and many-to-many communications. We show that one of our upper bounds is a tight bound. Also, we demonstrate that the capacity of MANETs with multiple antennas is improved significantly using cooperation as compared to non-cooperative schemes, i.e., point-to-point communication.

Multiuser diversity has been shown to increase the throughput of mobile ad hoc wireless networks (MANET) when compared to fixed networks. We present a different multiuser diversity strategy for packet relaying, which permits more than one-copy (multi-copies) of a packet to be received by relay nodes, thus allowing us to decrease the delay on such networks for a fixed number of total users n. We show that the /spl theta/(1) throughput is preserved by our multi-copy technique when n goes to infinity. In addition, we find that the average delay and variance scale like /spl theta/(n) and /spl theta/(n/sup 2/) respectively for both one-copy and multi-copies techniques. We also show that for a fixed n and by multi-copy forwarding, a maximum bounded delay value can he guaranteed.

Multiuser diversity has been shown to increase the throughput of mobile ad-hoc wireless networks (MANET) when compared to fixed wireless networks. This paper addresses a multiuser diversity strategy that permits one of multiple one-time relays to deliver a packet to its destination. We show that the /spl theta/(1) throughput of the original single one-time relay strategy is preserved by our multi-copy technique. The reason behind achieving the same asymptotic throughput is the fact that, as we demonstrate in this paper, interference for communicating among closest neighbors is hounded for different channel path losses, even when n goes to infinity. We find that the average delay and its variance scale like /spl theta/(n) and /spl theta/(n/sup 2/), respectively, for both the one and multi-copy relay strategies. Furthermore, while for finite n the delay values in the single-copy relaying strategy are not bounded, our multi-copy relay scheme attains bounded delay.

We investigate a method of communicating with chaos described by Hayes, Grebogi, and Ott (19913), which uses the idea of controlling chaos by small perturbations. Although allowing the electronics controlling the output signal to remain at the low-power level, this method unavoidably incurs a capacity loss, which we calculate for a chaotic CO/sub 2/ laser model. We first determine an approximation to the laser language, by means of a forbidden set representation, and then find its Shannon (1963) capacity. The results indicate that, since the capacity loss is not significant, the tradeoff is worthwhile. Finally, we point to simple finite-state encoders that satisfy the constraints imposed by the language.