Conventional distributed power control algorithms in cognitive radio networks are based on
the assumption of perfect channel state information (CSI) which may lead to performance …

To guarantee the continuity of secondary transmission (ST) in cognitive radio networks
(CRNs), a beamforming-based cognitive cooperative communication protocol, referred to as …

The authors consider co-existence of a secondary network with a primary network under an
overlay framework and propose beamformer design and power allocation using an iterative …

This paper presents a lower-bound on the ergodic sum capacity of single-input single-output
(SISO) opportunistic spectrum sharing multiple access channel (MAC) in Rayleigh fading …

Relaying of the primary signals by cognitive base-stations (CBSs) can help the primary
system and thus win CBSs a higher chance to transmit their own signals. For this purpose …

This paper studies the maximum number of users that can be allocated in the same
frequency band in case of using beamforming in a transmitter and a receiver by simulations …

Currently, the radio spectrum is beginning to be crowded due to the rapid growth of wireless
technologies this century. However, many studies show that the major licensed bands, such …

Radio spectrum is becoming increasingly scarce as more and more devices go wireless.
Meanwhile, studies indicate that the assigned spectrum is not fully utilised. Cognitive radio …

In cognitive relay systems, spectrum holes exist in 4 dimensions (4-D), namely, time,
frequency, location, and direction. How to efficiently utilize these different kinds of spectrum …

This paper focuses on a downlink beamforming problem in the cognitive radio (CR)
communication system where primary users (PU) coexist with secondary users (SU). It is …