A local call admission control (CAC) algorithm for third generation wireless networks was designed and implemented, which allows for the simulation of network throughput for different spreading factors and various mobility scenarios. A global CAC algorithm is also implemented and used as a benchmark since it is inherently optimized; it yields the best possible performance but has an intensive computational complexity. Optimized local CAC algorithm achieves similar performance as global CAC algorithm at a fraction of the computational cost. Design of a dynamic channel assignment algorithm for IEEE 802.11 wireless systems is also presented. Channels are assigned dynamically depending on the minimal interference generated by the neighboring access points on a reference access point. Analysis of dynamic channel assignment algorithm shows an improvement by a factor of 4 over the default settings of having all access points use the same channel, resulting significantly higher network throughput.

El trabajo realizado buscó unir los campos de redes inalámbricas de sensores y dispositivos móviles. El primero dada la riqueza de información y facilidad de despliegue de estas redes. El segundo, en relación a las grandes ventajas de dispositivos portados por los usuarios (ej. información constantemente disponible), existiendo casos de uso que podrían beneficiarse de la funcionalidad conjunta (ej. telemedicina). El objetivo fue desarrollar e implementar un sistema que comunicara nodos inalámbricos, algunos de los cuales sensaran variables de interés, mientras que otros monitorearan las mismas. El diseño se basó en la plataforma BUG, de BugLabs Inc., un start-up tecnológico de New York, USA. Esto pues se consideró de gran interés la filosofía propuesta por esta empresa: computadores compactos (posiblemente móviles) de arquitectura modular (el hardware se construye mediante la adición de módulos). El foco de esta plataforma es el prototipaje rápido de otros dispositivos. La solución propuesta incluye Nodos Sensores y Monitores Móviles, ambos elaborados con BUGs pero con distintos módulos. Los Nodos Sensores cuentan con adquisición de señales análogas y también conexión USB. El mismo módulo es usado en los Monitores Móviles (por esta última funcionalidad), además de una pantalla que constituye la interfaz con el usuario. La comunicación inalámbrica entre nodos se realiza mediante módems externos. Estos módems (radios XBee) implementan el protocolo IEEE 802.15.4, que fue desarrollado especialmente para uso en redes de sensores. Sus características son bajo consumo de potencia y facilidad en el establecimiento de redes sin necesidad de otro hardware (redes ad-hoc). Se utiliza una topología en estrella, requiriéndose de un coordinador. Luego de simples configuraciones iniciales, la red se establece automáticamente y el monitor (o monitores) recibe muestras de los sensores conectados a la red, las cuales despliega en la pantalla y almacena en memoria. Debido a problemas con las versiones preliminares del hardware disponible, el sistema fue probado emulando los nodos en un computador convencional, pero utilizando una interfaz de aire real (se conectaron varios XBee al computador). Se definió un protocolo de pruebas, obteniéndose resultados positivos ante cada evento. Se plantea como trabajo a futuro la realización de pruebas en terreno y el añadir funcionalidades de actuación además de monitoreo.

This work deals with the wireless Wi-Fi networks, that used unlicenced ISM frequency band 2,4 GHz. These wireless networks are very extended in these days and used mainly for the Internet connection. With the multimedia data transfers expanding it’s necessary to ensure the specific quality of service QoS in wireless networks mainly for applications, which are sensitive to delay or packets lost. The main aim of this work is to describe Wi-Fi networks based on IEEE 802.11b/g/n standards, description of QoS techniques according to IEEE 802.11e standard and description of parameters describing QoS for the VoIP services. The practical part is divided on a two parts. The problems of measuring the radio link quality and the creation of simple program for quality of wireless connection analysis are solved in the first part. The second part incluledes measuring of the lost packets number in Wi-Fi network with the commercial application AirMagnet Laptop Wireless LAN Analyzer and measuring of the signal noise influence with the help of spectrum analyzer and vector signal generator.

In the master’s thesis IEEE 802.15.4 Range measurements I want to find out, whether atmospheric conditions have influence over the quality of communication between two ZigBee modules. I would like found the answer by long-time test, because I can’t found the proper place for the measuring, I must found the answer in the literature. In the second part of the master’s thesis I measuring, whether placing one of the module in the car have influence over the quality of communication. The module was placing in the various places in the car, on a dashboard, on a guest-passenger’s seat, in a pocket before guest-passenger and in luggage compartment. The car for the measuring was used Renaul Scénic my. 2004.

The diploma thesis addresses facility of QoS control with GNU/Linux tools iptables and iproute. An attention is focused especially on HTB and HFSC traffic shaping methods with regard to utilization in wireless networks. The paper also includes a simulation of ensuring QoS in wireless network with 802.11e amendment.

The diploma thesis includes the ZigBee networks and compares them with other PAN IEEE 802.15.4 networks. It describes the formation of ZigBee networks. It describes physical, MAC, network and application layer in the form of Bitcloud. Thesis includes practical implementation in the form of ZigBee application BeeCon which allows set network parameters on Iris modules.

This thesis deals with the investigation and assessment of communication standards LTE-Advance and WiFi (IEEE 802.11n/ac). The EVM error parameter is examined for each standard. To work with different standards a universal workplace have been proposed (testbed). This universal workplace serves for adjusting transmitting and receiving means and for processing signals transmitted and interpreted. Matlab was chosen for this work, through which only control devices such as generators and analyzers from Rohde & Schwarz. This workplace also measures the coexistence of these standards. At the conclusion of this thesis, different coexistence scenarios were designed and evaluated through testbed results.

The object of this work is to study the IEEE 802.11ac standard, paying attention to the issue of the physical layer standard, to study in detail the use of MIMO and implement this technology into framework of WIFI simulator.

Frame aggregation is one of the major MAC layer enhancements in the IEEE 802.11 family that boosts the network throughput performance. It aims to achieve higher throughput by transmitting huge amount of data in a single transmit oppor- tunity. With the increasing awareness of energy e ciency, it has become vital to rethink about the design of such frame aggregation protocol. Aggregation techniques help to reduce energy consumption over ideal channel conditions. However, in a noisy channel environment, a new energy-aware frame aggregation scheme is required. In this thesis, a novel Green Frame Aggregation (GFA) scheduling scheme has been proposed and evaluated. GFA optimizes the aggregate size based on channel quality in order to minimize the consumed energy. GFA selects the optimal sub-frame size that satisfies the loss constraint for real-time applications as well as the energy budget of the ideal channel situations. The design, the implementation, and evaluation of GFA using testbed deployment is done. The experimental analysis shows that GFA outperforms the conventional frame aggregation methodology in terms of energy e ciency by about 6⇥ in the presence of severe interference conditions. Moreover, GFA also outperforms the static frame sizing method in terms of network goodput and maintains almost the same end- to-end latency.

In this paper, we introduce a clean-slate architecture for improving the delivery of data packets in IEEE 802.11 wireless mesh networks. Opposed to the rigid TCP/IP layer architecture which exhibits serious deficiencies in such networks, we propose a unitary layer approach that combines both routing and transport functionalities in a single layer. The new Mesh Transmission Layer (MTL) incorporates cross-interacting routing and transport modules for a reliable data delivery based on the loss probabilities of wireless links. Due to the significant drawbacks of standard TCP over IEEE 802.11, we particularly focus on the transport module, proposing a pure rate-based approach for transmitting data packets according to the current contention in the network. By considering the IEEE 802.11 spatial reuse constraint and employing a novel acknowledgment scheme, the new transport module improves both goodput and fairness in wireless mesh networks. In a comparative performance study, we show that MTL achieves up to 48% more goodput and up to 100% less packet drops than TCP/IP, while maintaining excellent fairness results.