Evaluation of required sensing time for multimedia transmission over cognitive Ultra Wideband system

Limited available spectrum and the inefficiency in the spectrum usage necessitate the use of cognitive radio (CR) approach to exploit the existing wireless spectrum opportunistically. To achieve the goal of CR, it is a fundamental requirement that the cognitive user (CU) performs spectrum sensing to detect the presence of the primary user (PU) signal before a spectrum is accessed to avoid interference from other wireless users. In ultra wideband (UWB) system which utilizes low power transmission, detection of PU is a key problem in a low signal-to-noise ratio (SNR) condition. This paper presents preliminary works in determining the quality of service (QoS) requirements for multimedia delivery in cognitive UWB. The proposed cross-layer design for multimedia transmission is presented. The paper also highlights the use of probability of detection to assess the channel conditions. Finally, we conclude with some future works on issues of medium access control (MAC) layer and time slot allocations for video applications.