The stringent requirements of wireless multimedia
transmission lead to very high radio spectrum solicitation. Although the radio spectrum is considered as a scarce resource, the
issue with spectrum availability is not scarcity, but the inefficient
utilization. Unique characteristics of cognitive radio (CR) such
as flexibility, adaptability, and interoperability, particularly have
contributed to it being the optimum technological candidate to
alleviate the issue of spectrum scarcity for multimedia communications. However, multimedia communications over CR
networks (MCRNs) as a bandwidth-hungry, delay-sensitive, and
loss-tolerant service, exposes several severe challenges specially
to guarantee quality of service (QoS) and quality of experience
(QoE). As a result, to date, different schemes based on source and
channel coding, multicast, and distributed streaming, have been
examined to improve the QoS/QoE in MCRNs. In this paper,
we survey QoS/QoE provisioning schemes in MCRNs. We first
discuss the basic concepts of multimedia communication, CRNs,
QoS and QoE. Then, we present the advantages of utilizing CR
for multimedia services and outline the stringent QoS and QoE
requirements in MCRNs. Next, we classify the critical challenges
for QoS/QoE provisioning in MCRNs including spectrum sensing,
resource allocation management, network fluctuations management, latency management, and energy consumption management. Then, we survey the corresponding feasible solutions for
each challenge highlighting performance issues, strengths, and
weaknesses. Furthermore, we discuss several important open
research problems and provide some avenues for future research.