Exploiting Multi-Antennas for Opportunistic Spectrum Sharing in Cognitive Radio Networks

—In cognitive radio (CR) networks, there are scenarios where the secondary (lower priority) users intend to communicate with each other by opportunistically utilizing the transmit spectrum originally allocated to the existing primary (higher priority) users. For such a scenario, a secondary user usually has to tradeoff between two conflicting goals at the same time: one is to maximize its own transmit throughput; and the other is to minimize the amount of interference it produces at each primary receiver. In this paper, we study this fundamental tradeoff from an information-theoretic perspective by characterizing the secondary user’s channel capacity under both its own transmit-power constraint as well as a set of interference-power constraints each imposed at one of the primary receivers. In particular, this paper exploits multi-antennas at the secondary transmitter to effectively balance between spatial multiplexing for the secondary transmission and interference avoidance at th...

• Type: Journal
• Year: 2007
• Where: CORR
• Authors: Rui Zhang, Ying-Chang Liang
• Keywords: CORR 2007, Education, Primary Receivers, Secondary Transmission, Secondary User