DDAS-DRoF Based a New In-Building Signal Coverage System Supporting Multiple Services

Aiming at the problems of low infrastructure utilization rate, high cost, large power consumption, inconvenient management and maintenance caused by independent in-building signal coverage systems of different operators, this paper puts forward a new in-building signal coverage system supporting multiple services based on digital distributed antenna system (DDAS) and digital radio over fiber (DRoF). The proposed system will not only support existing 2G, 3G and 4G mobile communication services, but also be able to provide access and coverage for future 5G and applications such as the internet of things (IOT) and in-building positioning. Radio frequency (RF) unit and digital signal processing (DSP) unit are designed independently to reduce the correlation and constraints between RF part and DSP part so as to facilitate increase or decrease supported service, dynamic capacity expansion and smooth upgrade. Each service corresponds to a kind of RF card and all RF cards share the same DSP platform. Test results of laboratory, simulation base station and actual mobile network show that proposed system is able to support designed services and performance indexes meet the specified requirements of 3GPP and mobile operators well. This may provide a good platform for co-construction and sharing, saving capital expenditure (CAPEX) and operating expenditure (OPEX) and reducing energy consumption of in-building signal coverage system. It also complies with the development trend of multi-network integration and internet plus.