LEM Architecture

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The LEM adopts a layered architecture. The lower mechanism layer hides technological idiosyncrasies and provides uniform functions to: i) access/control Wireless Network Interface Card (WNIC) and gather received signal strength indication (RSSI) monitoring data; ii) manage and render multimedia flows via standard application-layer protocols, such as Real-time Transport Protocol (RTP), and standard APIs, such as Java Media Framework (JMF).

LEM Architecture
LEM Architecture

The higher LEM facility layer consists of three main components that interwork to handle the three core management functions.

  • RSSI-based mobility monitoring triggers promptly, and possibly proactively, relay handoff management and streaming (de-)activation toward clients that exit/enter the AOI.
  • AOI topology self-reconfiguration chooses and accommodates/detaches clients in the circular crown around the centermost relay; in addition, it elects the new relay in case of handoff.
  • Multimedia streaming & continuity realizes the relay handoff protocol, by ensuring data continuity via a two-level buffering solution, with one buffer stored at client and one at relay, and is responsible and controls all multimedia flow transmissions within the AOI.
RSSI-based mobility monitoring, AOI topology self-reconfiguration, and Multimedia streaming & continuity components dynamically form a pipeline; each stage of the pipeline exploits output data from the previous stage to trigger control actions over the following stage.