Challenges in Deploying Steerable Wireless Testbeds

Abstract

Phased array antennas enable the use of real-time beam-forming and null-steering to further increase control of signal and interference in wireless networks. Understanding the potential of this platform for both wireless mesh networks and single-hop networks is becoming more important as smart antennas begin to emerge in networking standards such as IEEE 802.11n and 802.16. Prior attempts to test non-standard antenna platforms have typically focused around simulations, fixed directional antenna testbeds that are unable to perform null-steering, and small scale temporary setups utilizing 1 or 2 phased array antenna nodes over the span of a few hundred meters. This paper presents the challenges encountered -and solutions developed -in building WART, a permanent, campus-wide testbed for wireless networking with beam-forming antennas. We use affordable commercial off-the-shelf (COTS) hardware as both a measurement apparatus and the system under test. This approach makes it possible to develop and test networking protocols using equipment similar to what may be available operationally, but also presents difficulties beyond those typically encountered with specialized measurement hardware. We show that system-level techniques can adequately overcome those component limitations.

Extensão do Plano de Controle Sem Fio para Ambientes Experimentais Outdoor

“…Testbeds" desenvolvido por Anderson, E. [7] juntamente com a Universidade do Colorado é apresentado uma plataforma chamada Wide-Area Radio Testbed (WART) para estudos de antenas em redes sem fio, como direcionais, adaptativas, inteligentes entre outros. A validação da proposta apresenta uma infraestrutura física e funcionalidades de controle de energia do nodo experimental, ou seja, ligar, desligar e saber o status através de rede sem fio, além de propor um método de resiliência do plano de controle.…”

“…Tal característica habilita resiliência, reduzindo a possibilidade de falhas, como apresentado em Vasconcelo, F. M. e Salles M [12]. O artigo publicado por Anderson [7] apresenta resiliência sem fio em ambientes experimentais outdoor, porém não garante a inteligência computacional necessária para atender todas as funcionalidades do plano de controle utilizando o nodo Icarus, limitando-se ao controle de energia, como ligar ou desligar um nodo experimental.…”

Bounding the Practical Error of Path Loss Models

“…Finally, the third C, concerns infrastructure network configurations where one fixed well-positioned transmitter (AP) is responsible for serving multiple ground-level mobile nodes. uniform circular phased-array antennas [58]. The devices are mounted on rooftops on the CU campus and in the surrounding city of Boulder, CO (see Figure 3).…”

Predicting throughput in IEEE 802.11 based wireless networks using directional antenna

“…Omnidirectional antenna (OA) is the only antenna supported by the IEEE 802.11 standard [5] but there are many directional antenna (DA) based IEEE 802.11 networks that have been deployed [6][7][8][9][10]. The advantage of using DA [11,12] include the following: (1) a node could send signals to desired directions allowing the receiver node to avoid interference that comes from unwanted directions; this increases the signal to interference plus noise ratio (SINR); (2) the higher spatial reuse factor of DA, when compared to OA, could allow for more users to utilize a network simultaneously; (3) a source node could potentially reach its destination node in a lesser hop count in multihop scenario, due to the increased transmission range obtained from the higher gain of antenna.…”