Software-Defined Radio Network Positioning Technology Design. Receiver Processing Procedures

Purpose of software-defined radio (SDR) network positioning technology design is substantiation and experimental validation of new technical solutions for user equipment (UE) location estimation improvement, using infrastructure of existing 4G Long-Term Evolution (LTE) and emerging 5G New Radio (NR) networks, which is highly relevant in Global Navigation Satellite System (GNSS) denied urban environments. Approach for experimental validation is prototyping of eNodeB (eNB) reference signals transmission and UE reception procedures using SDR testbed with Universal Software Radio Peripheral (USRP) hardware and Matlab software. Generation and transmission of reference signals, performed by eNB on the physical layer, is defined by 3GPP technical specification 36.211, and receiver processing procedures, performed by UE, and strongly affecting the accuracy of primary measurements, can be designed as a proprietary solution. Findings of current research include formalization, software realization and results of experimental validation of a sequence of procedures for receiving and processing LTE reference signals in order to collect primary range-difference measurements on the UE side for observed time difference of arrival (OTDOA) positioning with developed SDR testbed. Research and development campaign on the current stage has limitation of SDR testbed validation only in laboratory conditions. Practical implications of developed UE SDR testbed allow to proceed campaign to the field conditions and test proposed technical solution with ambient LTE signals.