Transmission power and capacity of secondary users in a dynamic spectrum access network

In this paper, we analyze the capacity of secondary spectrum access in a broadcasting system consisting of one primary transmitter and multiple primary receivers. At the cost of a small redundancy of the SINR of primary receivers, secondary users can gain a significant capacity when allowed to share the spectrum at the same time with the primary transmitter. The average transmission power and capacity of secondary users are derived, evaluated numerically, and verified by simulating a simple dynamic spectrum access protocol. The results show that the capacity depends on the distance between primary and secondary transmitters as well as the density of primary receivers.