Base station assisted communication system for achieving local-oscillator-less mobile stations

Abstract

This paper proposes a novel system concept in which has base stations (BSs) assist in part of mobile station (MS) functions for future mobile communications in the fifth generation era. In the proposed system, two BSs provide different signals: one transmits a modulated signal with the bandwidth and the other transmits a continuous wave (CW) signal at a different frequency. The CW signal is utilized as a local signal to detect the received modulated signal at the MSs. An advantage of this scheme is that the radio frequency frontend configuration of the MS is simplified because it is not necessary to implement a local oscillator with a high frequency and high purity. However, since the CW signal is received with the modulated signal at the MS, its receiver must appropriately extract the CW signal from the received signals. Therefore, this paper also presents a novel receiver that has a CW extraction function. To confirm the feasibility of the proposals, a transmission system including the proposed receiver is constructed and tested at around 3.9 GHz. Measurement results show that an adequate quality level with the EVM degradation of approximately 0.1% is achieved using the extracted CW signal from the received signals.