Coverage optimization for Minimization of Drive Tests in LTE with extended RLF reporting

In this article we have studied the coverage optimization for 3G Long Term Evolution (LTE) according to Minimization of Drive Tests (MDT) work item description in Third Generation Partnership Project (3GPP). Target for the MDT work item is to define a set of measurements and measurement reporting procedures, so that operators are able to collect measurement data from users and thereby reducing need for manual drive tests. The main focus of MDT is coverage optimization. We propose an extended Radio Link Failure (RLF) reporting for both coverage and mobility optimization use cases for MDT. In this paper the MDT studies and especially the benefits of extended RLF reporting and classification are analyzed by means of dynamic system level simulations. The RLFs are classified into three categories based on the content in extended RLF reports: coverage, handover parameterization and interference problem. It can be concluded that the coverage as well as other problems may be identified with quite high probability with only a minimal standardization effort.