Simultaneous reception and sensing using multiple antennas in cognitive cellular networks

We consider the problem of sensing in the presence of a desired signal in the context of future 3GPP LTE-A based cognitive cellular systems employing multiple-input multiple-output (MIMO) transmission. Energy detection (ED) based on equal gain combining and beamforming are investigated. Receive beamformers for energy detection (ED) are designed according to the Neyman-Pearson criterion to maximize the probability of detection for a given probability of false alarm. Suitable suboptimum solutions to the maximization problem with a good tradeoff between performance and complexity are identified. Furthermore, we also formulate the likelihood ratio test (LRT) for this scenario. Performance simulations indicate that a significant performance gain is achieved in ED if the receive beamformer is chosen properly.