Context-Aware Handoff Management

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The visibility of handoff-related context information is essential to operate effective handoff management operations and should include handoff type and characteristics, transient or definitive QoS degradation associated to handoff occurrence, and changes of local provisioning environment due to client handoff between WI access localities.

 

MUM context model can be logically divided in three parts:

  1. Handoff awareness to enable effective management actions via full visibility of employed handoff procedures and parameters.
  2. QoS awareness to actively participate to the management of service components according to service requirements and QoS degradation due to handoffs.
  3. Location awareness to enable runtime decisions based on client mobility, network topology, and current resource position.

 

MUM Context Model

Each context part includes various properties (see the table) that report all handoff, QoS, and location related information necessary to the MUM middleware to autonomously operate handoff management operations.

 

Context Part

Properties

Handoff Awareness
  • Involved wireless infrastructures and handoff direction: Horizontal/Vertical
  • Inter-cell procedure type: Soft/Hard
  • Detection method: Proactive/Reactive

QoS Awareness
  • Latency
  • Data Loss
  • Content Adaptation

Location Awareness
  • Geographical scope: Micro (intra-subnet)/Macro (inter-subnet)/Global (inter-domain)
  • Service Re-bind
  • Context Transfer

Context Taxonomy and Properties

 

 

MUM Service Requirement Specification

To grant service continuity MUM also needs to know service requirements.

MUM adopts standard Service Level Specifications (SLS) to express service requirements service requirements.

 

In particular, MUM requires the application to declare service tolerance with regards to the following parameters:

  • Delay
  • Jitter
  • Data losses

Let us stress that SLS is the only service layer information necessary to the middleware to transparently complete handoff management procedures without any other service level intervention.

 

In addition, MUM adopts standard XML-based formats, based on both Dublin Core (DC) and MPEG7 by Multimedia Picture Experts Group (MPEG), to represent metadata describing static characteristics of delivered multimedia streams (data encoding, frame size, ...).

 
8-nov-06