A phased array antenna testbed for evaluating directionality in wireless networks

ABSTRACT

One of the most important components of any mobile system is the antenna; antenna design can overcome or cause a number of problems that then must be addressed at other technology layers. Modern mobile platforms are beginning to include novel antenna technology such as MIMO and beam steering; these technologies increase the complexity of evaluating the effectiveness of topology formation algorithms, routing and overall performance due to the large number of configuration states the system can contain. Directional antennas allow for significant improvements in link quality and spatial reuse in wireless communication. Traditional antennas with fixed direction are effective but unable to respond to station mobility or a dynamic environment including such factors as wind and foliage growth. There is a growing body of work on using steerable and sectored antenna systems to harness the efficiency of directional antennas while retaining the flexibility of ad-hoc networks; however, there has been very little work on implementation and measurement of such networks.

We examined the physical-layer properties of directional links in two real RF environments, and have evaluated higher-layer strategies for utilizing these antennas. Our results indicate the topology formation process must be a network operation, and that simple link-by-link topology optimization is likely to lead to poor overall performance. These observations drive the formation of the testing and evaluation tools we have developed. This paper describes the tools, methodology and metrics we are using in the evaluation of topology formation algorithms using a dynamically steerable phase array system.

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INDEX TERMS

Primary Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.1 Network Architecture and Design
          Subjects: Wireless communication

Additional Classification:
  B. Hardware
  B.4 INPUT/OUTPUT AND DATA COMMUNICATIONS
      B.4.1 Data Communications Devices

General Terms:
Design, Experimentation, Measurement, Performance

Keywords:
802.11, RSSI, SINR, antenna, directional, phased array, steerable, testbed