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Cognitive radio is a dynamic technology that has a potential of addressing the spectrum scarcity challenge. However, routing in cognitive radio network is a challenge. The availability of the spectrum is probabilistic and it varies from one zone to other. The existing protocols do not guarantee the quality of service requirements for real-time data. Some of the challenges affecting the design of quality...
Spectrum decision is the key function of a cognitive radio(CR) to choose the most proper spectrum band to meet secondary users'(SUs') quality of experience(QoE) requirements. It is challenging to perform spectrum decision for multimedia applications in cognitive radio networks(CRNs) due to two reasons. One is that QoE evaluation model for SU in CRNs is still an open issue, for the conventional QoE...
In this paper, we investigate fundamental throughput and delay tradeoffs in cognitive radio networks (CRN) with a primary user (PU) and a cooperative secondary user (SU). Considering the user fairness, we propose a novel cooperation scheme, where the PU transmits packets with a probability of α instead of always occupying the spectrum, in exchange for the SU's cooperation. The unauthorized SU can...
In this paper, we use a Spectrum Sharing/allocation algorithm to implement a Cognitive Radio network without spectral awareness. This allows radio resources to be allocated to primary users and to secondary users in such a way that primary system and secondary system are aware of each other. By doing this, sensing of spectrum holes is avoided but the primary users will be protected and will always...
We consider a cognitive radio network, where primary users have priority over the spectrum resources, and secondary users can exploit the unused resources through channel sensing. Due to sensing inaccuracy, the secondary traffic may obstruct the primary traffic. A penalty for collision has been used to protect the primary traffic, which is often designed to provide a fixed per-collision compensation...
Recently, the demand for faster and more reliable data transmission has brought up complex communications systems. As a result, it has become more difficult to carry out closed-form solutions that can provide insight about performance levels. In this paper, different from the existing research, we study a cognitive radio system that employs hybrid-automatic-repeat-request (HARQ) protocols under quality-of-service...
In this paper, we propose a novel network model for RF-powered cognitive radio networks and ambient backscatter communications. In the network under consideration, each secondary transmitter is able to backscatter primary signals to the gateway for data transfer or to harvest energy from the primary signals and then use that energy to transmit data to the gateway. To maximize overall network throughput...
In this paper, we consider the utilization of TV White Spaces (TVWS) by small Cognitive Radio (CR) wireless network operators (SCWNO) to support the communication needs of various smart grid and internet of things (IoT) applications. Spectrum leasing could be essential for SCWNO to support a wide range of applications. In our paper, we assume that in order to ensure Quality of service (QoS) requirements,...
In this paper, we study the resource allocation issues related to OFDM-based multiuser cognitive radio cellular networks, where both of primary network and secondary network are investigated to make an all-round evaluation of the network performance, including the Quality of Experience (QoE) of the primary users (PUs) and the minimal rate requirement of the secondary users (SUs). Since the general...
Cognitive radio (CR) is the current growing technology in wireless communication field and has increase the ability to use the frequency spectrum more properly. The main objective of cognitive radios is to sense the surrounding and use primary user's vacant spaces and allot them to the secondary users without interference each other. This paper presents the optimal solution and optimizes the Quality...
Recent years have shown an increase demand for wireless communication which creates new challenges in the field where intelligent spectrum utilization is necessary to maintain high network performance. The emergence of Cognitive Radios which provide opportunistic access to the spectrum, introduce an improvement in the spectrum utilization and the communication quality. Through dynamic spectrum access...
In this paper analysed different spectrum decision methods in a Cognitive radio network. An analytical system model proposed to compare channel selection algorithms by main operational parameters to minimize total system selection time. The considered methods which are based on balancing traffic load can distribute secondary users load to multiple channels, in contradistinction to non-load-balancing...
Systems comprised of Cognitive Radio Networks (CRN) have been gaining attention in the current literature, given their ability to reduce spectrum scarcity by reusing parts of the spectrum band, while at the same time ensuring a minimum Quality of Service (QoS) margin. In this regard, it becomes important to consider the CRN's usage of multiple access protocols. In this paper, we consider a CRN with...
In this paper, we propose the concept of "channel+ beam" hando2642 (CBH) in cognitive radio networks (CRNs) with multi-beam smart antennas (MBSAs). We address the multi-class spectrum hando2642 issue, based on the user priority, by using the mixed Preemptive/Non-Preemptive M/G/1 queueing model with discretion rule. The discretion rule sets the threshold for the preemption of the low-priority...
Dynamic spectrum access is an important issue in cognitive radio networks (CRNs) as secondary users (SUs) can benefit from accessing the vacant licensed channels of primary users (PUs). In this paper, we consider the problem of competitive distributed spectrum access in CRNs with quality of service (QoS) constraints. We first propose a distributed matching algorithm (DMA) to handle spectrum access...
Abstract-In cognitive radio networks, secondary users (SUs) face two conflicting objectives. Each SU seeks to minimize the sensing duration while maximizing the detection probability of primary users (PU) to avoid interfering with their transmissions. Both objectives have a substantial effect on energy efficiency. This paper investigates a noncooperative setting for selecting the sensing duration...
As a critical technique to support the multimedia services - the major traffic in cooperative cognitive radio networks (CRNs), the statistical quality-of-service (QoS) technique has been proved to be effective in statistically guaranteeing delay-bounded video transmissions over the time- varying wireless channels. On the other hand, in modern cooperative CRNs, the full-duplex spectrum sensing (FD-SS)...
In this paper, we consider an underlay cognitive radio (CR) multicast network where secondary users (SUs) coexist with primary users (PUs). The cognitive radio network (CRN) consists of a cognitive base station (CBS) and multiple multicast groups. Each multicast group comprises of a number of SUs and is served by the CBS using a common PU channel. Our objective is to minimize the aggregate group outage...
Dynamic spectrum allocation techniques are usually based on the assumption of a homogeneous cognitive radio network. In this work we describe a Continuous time Markov chain model that allows different types of bandwidth requirements and priority traffic. We have improved the lowest priority user's performance using channel aggregation and fragmentation, which are mechanisms envisioned for the LTE-A/4G...
In this paper, the performance of heterogeneous traffic Cognitive Radio Networks (CRNs) with spectrum adaptation and spectrum leasing is mathematically analyzed and evaluated. Spectrum adaptation and spectrum leasing are used jointly with spectrum handoff, call buffering, and preemptive priority mechanisms to improve system performance. Two different spectrum leasing strategies are proposed and evaluated...
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