The current framework does not make the use of Cognitive Radio Networks (CRNs) along with NOMA. The goal of CRNs is to provide high Spectral Efficiency (SE) and high Quality of Service (QoS) to both Primary User (PU) and Secondary User (SU). In order to achieve desired functionalities of power domain concept in NOMA at the receiver, channel gain difference between users should be adequate. This limits effective number of users. Integrating CR (Cognitive Radio) networks with NOMA can improve system capacity and hence can increase the number of users as compared to traditional NOMA.
- Cognitive radio (CR) [10], [11] as an emerging technology is proposed to provide high spectrum in which SUs are allowed to access the spectrum when PU is absent. It can achieve the highest accuracy when the probability of Detection is the highest and probability of false alarm is the lowest.
- Low false alarm probability indicates highly reliable detection of the idle channel, while high detection probability means highly accurate detection on the presence of the PU (Primary User). The sensing time decides the detection performance, which can be increased to decrease false alarm probability and improve detection probability.
- Cognitive radio (CR) provides high Spectral Efficiency (SE) . It can enable the secondary network ( unlicensed network) to access the licensed frequency bands of the primary network by using adaptive transmission strategies while protecting the quality of service (QoS) of the primary one.
- Non-orthogonal multiple access (NOMA) techniques improve Spectral Efficiency (SE) and user connectivity density . Unlike the conventional orthogonal multiple access (OMA) techniques, NOMA techniques allow multiple users to simultaneously access the network at the same time and the same frequency band by using non-orthogonal resources, such as different power levels or low-density spreading codes.
- In CR-NOMA, occasionally, the unlicensed secondary users (SU) can be served the same quality of service (QoS) conditions as the licensed primary users (PU)
- It can achieve higher spectral effect because both PU and SU can work well using the same spectrum at the same time.
- CRNs with NOMA leverage secure transmission techniques. Due to the broadcast nature of NOMA and the open nature of CR, malicious NOMA SUs may exist and illegitimately access PUs’ frequency bands or change the radio environment. As a result, a legitimate SU is unable to use frequency bands of a PU. Thus, secure transmission techniques are of crucial importance which are provided by CRNs with NOMA.
For detailed description of Perfromance analysis, system model explaination and results refer this report :- https://github.com/varshil1/Spectrum-Utilization-of-cognitive-radio-networks-Using-NOMA/blob/master/NOMA_S16_Final_Report.pdf