LBS Reference Model

Location-based services (LBS) have already found their place in modern world of telecommunications and their future is certainly not questionable. However, LBS quality of service (QoS) definition is still in its infancy, preventing fast and concerting LBS development. Lack of suitable formal description contributes to complexity of system architecture, system integration and related software development. Besides, setting LBS QoS requirements presents extremely difficult task to solve, with direct consequences to the LBS commercial success. So far, only the set of positioning methods applicable for LBS development is identified and specified, with agreement for it reached among the telecommunications community. After thorough analysis, our team has recently proposed the requirements for positioning performance, as a foundation element for LBS QoS definition. While working on this issue, we have developed a number of achievements that finally leads to a definition of formal LBS positioning reference model (LBS RM). LBS RM identifies three main layers aimed to provide the best available position estimate (BAPE), offering a range of positioning performance levels suitable for LBS hierarchical structure development. In that case, LBS hierarchy could be fairly easily driven by user requirements and needs, assuring their commercial success. In addition, LBS RM is designed in order to give strong support to optimal positioning system integration. New positioning concepts (like distributed positioning concept) are also easily deployable using LBS RM. LBS RM has been validated in practice during the satellite positioning-based automatic position reporting system (APRS) development. A very complex technology integration task was successfully completed using LBS RM, allowing synergy between different communications protocols, system architectures and positioning algorithms. LBS RM-based APRS performance was validated during the field trial performed in the Zagreb city centre. Trial results confirm the LBS RM contribution to the APRS development. This research article presents LBS RM as both general model for LBS description, and framework for LBS solution development. APRS is presented as the LBS RM case study, with detailed results of the Zagreb city centre field trial. Integration challenges are documented, along with discussion of positioning performance improvement and the impact on general LBS QoS requirements definition. Finally, a proposal for LBS QoS is presented, based on LBS RM implementation.