Estimation of prior positioning method performance in LTE

Public Land Mobile Network (PLMN) or cellular network location based services use multiple positioning methods in order to fulfill requirements in terms of availability, response time and accuracy. This is needed since no single method performs uniformly best, for all services at all locations. Very often more than one positioning method needs to be applied in a fallback manner, or in LTE in parallel, to arrive at a good enough User Equipment (UE) positioning result. At the beginning of this positioning sequence, no measured data exist and hence the evolved serving mobile location center (eSMLC) needs to compare the requested QoS from the end user with prior performance capabilities of the available positioning methods, to find the best positioning method sequence for the request. The paper proposes new techniques for on-line estimation and adaptation of this prior performance information. The proposed algorithms also provide detailed information on the confidence of the prior information, i.e. the probability that the terminal is actually located in the estimated region. The need for and the effect of transformations between reporting formats are also discussed and two such shape conversions are derived.