Sensing Algorithms and Protocol for Simultaneous Sensing and Reception-Based Cognitive D2D Communications in LTE-A Systems

Abstract

We explore the application of simultaneous sensing and reception (SSR) for cognitive communication in orthogonal frequency division multiplexing (OFDM)-based wireless systems such as 3GPP LTE-A which may find application in multi-tier spectrum sharing paradigms such as the spectrum access system. In such a system, a cognitive radio (CR) synchronized to the macro base station (BS) is assumed to exploit the spectral holes in the OFDMA time-frequency grid. We analyze the impact of timing alignment in such a system and show that power control and guard bands are essential to support such an operation. Practical algorithms for SSR with the constant false alarm rate property are developed using the generalized likelihood ratio test principle to protect macro BS users occupying the same transmission resources as the CRs. Subsequently, we propose a transmission-reception protocol with SSR for bidirectional communication between two time-division duplex CRs and compare it to a protocol with only sensing before transmission (SBT). The simulation results show that the sensing overhead in traditional SBT protocols can be much reduced with the use of SSR when the BS activity in adjacent slots is highly correlated.