Software Defined Radio Implementation of an LTE Downlink Transceiver for Ultra Dense Networks

In this paper, we present a real-time software-defined radio (SDR) solution for an LTE downlink transceiver in ultra dense networks (UDN). This SDR platform integrates the processing power of CPU and GPU and commercial RF transmitting and receiving frontend instruments. Most of the UDN receiver baseband processing is carried out via OpenCL programming language running on a GPU. In the over-the-air (OTA) UDN demonstration, we emulate three 4G LTE basestations: one strong interference macro basestation (MBS) and another weaker interference from a neighboring pico basestation (PBS), plus the serving PBS. The receiver implements all LTE MIMO-OFDM baseband processing and the data detection is achieved by a novel interference-aware MIMO detection scheme. An associated GUI displaying real-time channel estimation outcomes and UDN receiver performance is also developed. Finally, the prototype successfully demonstrates real-time reception of 10-MHz two-stream LTE signal under two interference sources.