A scalable collusion-resistant multi-winner cognitive spectrum auction game

As the novel and effective approach to improving the utilization of the precious radio spectrum, cognitive radio technology is the key to realize the dynamic spectrum access (DSA) networks, where the secondary (unlicensed) users can opportunistically utilize the unused licensed spectrum in a way that confines the level of interference to the range the primary (licensed) users can tolerate. However, there are many new challenges associated with cognitive-radio-based DSA networks, such as the multi-channel hidden terminal problem and the fact that the time-varying channel availability differs for different secondary users, in the medium access control (MAC) layer. To overcome these challenges, we propose an efficient Cognitive Radio-EnAbled Multi-channel MAC (CREAM-MAC) protocol, which integrates the cooperative sequential spectrum sensing at physical layer and the packet scheduling at MAC layer, over the wireless DSA networks. Under the proposed CREAM-MAC protocol, each secondary user is equipped with a cognitive radio-enabled transceiver and multiple channel sensors. Our cooperative sequential spectrum sensing scheme improves the accuracy of spectrum sensing and further protects the primary users. The proposed CREAM-MAC enables the secondary users to best utilize the unused frequency spectrum while avoiding the collisions among secondary users and between secondary users and primary users. We develop the Markov chain model and M/GY/1 queueing model to rigorously study our proposed CREAM-MAC protocol for both the saturation networks and the non-saturation networks. We also conduct extensive simulations to validate our developed protocol and analytical models.

ABSTRACTThe rapid expansion of the Internet of Things (IoT) and the increasing demand for wireless communication have intensified the need for efficient spectrum management in cognitive radio networks (CRNs). Traditional approaches to spectrum sensing and allocation often operate in isolation or rely on static methods, which fail to address the dynamic and evolving nature of modern wireless environments. As IoT devices proliferate and spectrum resources become increasingly congested, there is a pressing need for more adaptive and efficient spectrum management solutions. Our approach addresses this need by offering an adaptive framework that responds to the changing spectrum landscape, thereby optimizing spectrum usage and reducing interference. This research suggests improved NN joint spectrum sensing for CR‐IoTNet (INJSS‐CR). This approach leverages cognitive radio (CR) technology to enhance spectrum utilization and mitigate the impact of spectrum shortages. CR technology enables secondary users (SUs) to detect and access unused spectrum through spectrum sensing. Within the CR‐IoTNet framework, joint spectrum sensing and allocation are performed to serve SU‐IoT devices via an interference‐free channel (IFC). The system comprises multiple primary user base stations (PU‐BSs) and SU devices functioning as IoT smart objects. Additionally, we integrate an improved neural network (INN) to adapt to dynamic network conditions and monitor primary user (PU) spectrum utilization using a comprehensive multiclass (J × 8) − D feature set. This combination of advanced techniques and CR technology aims to optimize spectrum management and support the growing IoT ecosystem. In particular, the INJSS‐CR obtained the greatest accuracy of 0.9492 at a training rate of 80%.

Although cognitive radio technology improves efficiency of spectrum utilization, primary users usually do not gain from opening up the spectrum in the opportunistic spectrum access, and sometimes even suffer from collisions due to secondary users' imperfect spectrum sensing. However, in this paper, we show that if information secrecy is a concern, primary users could actually be better off by allowing secondary users to cooperatively share the spectrum. Specifically, we propose a new cooperation paradigm in cognitive radio networks that primary users improve secrecy with the help of trustworthy secondary users, in the presence of an intelligent and passive eavesdropper attempting to decode primary users' messages. After deriving the achievable pair of primary users' secrecy rate and secondary users' transmission rate under various circumstances, we model the interaction between primary users and secondary users as a Stackelberg game in which transmission power levels are the key to maximize data rates. Moreover, based on a 2-D representation of how achievable rates depend on power-level regions, we apply equilibrium analysis to understand the optimal strategy of primary and secondary users. Finally, simulation results are presented to verify the performance.

The spectrum scarcity problem can be tackled by promoting a more efficient use of the radio spectrum. Spectrum sharing techniques like TV White Spaces (TVWS), Licensed Shared Access (LSA), and Spectrum Access System (SAS), are adequate solutions for this problem and there exist already regulation and standardization efforts worldwide. To evaluate the coexistence between primary and secondary spectrum users, a Long Term Evolution (LTE) multi-cell simulator has been designed, which employs a generic spectrum sharing technique, Dynamic Spectrum Access (DSA), in order to obtain additional network capacity. As a way to bring attention and confidence of the telecommunications sector regarding the benefits that this technology may bring, the analysis is done in terms of interference suffered by incumbents (primary users) and capacity by secondary users. Results have confirmed the unfeasibility of co-channel coexistence for moderate distances between the cordless camera service (incumbent) and LTE network (secondary user) due to high interference. However, for adjacent bands, a gain of 40% in the secondary users’ capacity is possible following more restrictive interference protection requirements and 30% gain with the smaller frequency separation between primary and secondary operating frequencies.

Dynamic spectrum access has been proposed to address the spectrum scarcity. Based on this access mode, secondary users are allowed to opportunistically operate when primary users are absent. Secondary Users are, however, required to relinquish the spectrum upon return of the incumbent spectrum holder. Although it improves spectrum utility, opportunistic spectrum access limits secondary users' access to exogenous spectrum holes vacated by primary users. We argue that spectrum holes should be endogenous, enabled by incentives to incumbent users to increase spectrum availability, while mitigating risk. To this end, we take a different perspective on dynamic spectrum sharing and propose a coopetive framework, whereby primary and secondary users engage in a cooperative, yet competitive, auction-driven spectrum sharing to enhance spectrum usage. In this framework, the primary users'spectrum is organized in three bands, namely exclusive usage, usage right and management right bands. Based on this structure, spectrum is traded as financial options to increase trading flexibility and capture the value primary and secondary users attach to spectrum access and usage. Spectrum trading between primary and secondary users is formalized as a utility maximization problem. Approximate solutions to this problem are derived and their performance is analyzed. The results show that spectrum trading, which combines revocable and exclusive leasing, provides higher utilities for both primary and secondary users.

Cognitive radio (CR) and dynamic spectrum access (DSA) are the effective ways to solve the spectrum congestion problem. Three kinds of basic DSA approaches are respectively dynamic exclusive use, open sharing and hierarchical access. The hierarchical access model is perhaps the most compatible with solving the current spectrum congestion problem. So, in this paper, we will set up an overlay DSA system which is an effective approach of the hierarchical access model. Firstly, we make use of the spectrally modulated spectrally encoded (SMSE) framework to generate OFDM waveforms for the secondary user (SU) which can be considered as the overlay waveform. Then we use the signal which is generated by the walkie-talkie to access the overlay DSA system as a primary user (PU) or an interference signal. The universal software radio peripheral (USRP) and spectrum analyzer are used to generate and analyze the power spectrum density (PSD) of the coexistence of a SU and a PU or an interference signal. The experimental result demonstrates that the overlay DSA system can achieve the function of turning off the sub-carriers corresponding to the frequency of the PU. It also shows that the system can greatly improve the efficiency of the spectrum utilization due to dynamically allocate the spectrum.

In this paper, we investigate an online spectrum auction problem in cognitive radio networks with uncertain activities of primary users (PUs). In our framework, a primary base station (PBS), acted as the spectrum auctioneer, leases its under-utilized channels to secondary users (SUs) who request and access spectrum on the fly. Different from most of existing works in online spectrum allocation, we focus on a more practical situation that the auctioneer (or the PBS) has no prior knowledge of PUs' activities so that its channel states are not static. In order to balance the auction profits from granted SUs' spectrum requests and the potential penalties caused by incomplete services to PUs, we introduce the idea of virtual spectrum sellers and formulate the problem as an online double spectrum auction. We then propose a novel online admission and pricing mechanism which also considers the reusability of wireless spectrum. Theoretical analyses are provided to prove that our auction algorithm satisfies all desired economic properties in terms of budget-balance, individual rationality and truthfulness. Simulation results show that our proposed auction algorithm can increase the utility of the PBS, enhance spectrum utilization and achieve better satisfaction for SUs compared to counterparts.

In order to fully utilize the scarce spectrum resources and improve the efficiency of wireless spectrum resource utilization, dynamic spectrum access is proposed as a solution. There are two kinds of dynamic spectrum access system, one is overlay dynamic spectrum, and the other is dynamic spectrum access under interference temperature constraints. In this paper, we use a three-dimensional Markov chain to model the dynamic spectrum access under interference temperature constraints, and analyze the performance of secondary users in the system. Two important parameters, i.e., secondary user interrupting probability and blocking probability are derived using the proposed model. The performance of secondary users in different dynamic spectrum access systems are analyzed and compared. The numerical results show that the performance of secondary users can be improved significantly in dynamic spectrum access under interference temperature constraints comparing to overlay dynamic spectrum access. Specially, the advantage of interference temperature constraints based dynamic spectrum access is more notable on the condition that there are not enough resources to provide to secondary users for access.

In wireless communications, efficient use of spectrum is most challenging task. Cognitive radio is a promising technology to overcome the spectrum scarcity problem and provide efficient way of utilizing spectrum resources by dynamic spectrum access (DSA). In this paper, we have considered the situation where primary user (PU) i.e. licensed user and secondary user (SU) i.e. cognitive radio, share the spectrum simultaneously. We have developed a mathematical model for probability of detection as a function of distance between PU transmitter and SU transmitter. We have used this model to adjust the transmit power of SU while maintaining a quality-of-service for the PU by limiting the interference generated by SU.

A prototype Dynamic Spectrum Access (DSA) system is implemented, for ease of implementation, using the audio spectrum. In this setup, laptop PCs behave as two software defined radios (SDR), one a primary user (PU) and the other a secondary user (SU). The radios communicate digital information over the air, using the audio capabilities of standard soundcards. The PU, which is emulating the licensed user of an audio channel centered at 4 kHz, communicates using binary phase shift keying (BPSK) modulated data in periodic bursts. A cognitive radio (CR) based SU wishes to opportunistically occupy the PU channel during the inter-burst times, i.e. during the temporal ‘spectrum holes,’ while not interfering with the PU traffic. The PU link is implemented in MATLAB, while the SU is defined in GNU Radio with a separate Python control module defining its algorithm for spectrum sensing and hopping. The implementation of both communication links is described, as well as the initial performance evaluation of the preliminary system in terms of bit error rate performance of the PU with and without the presence of an active SU. The measured BER achieved for the best of the PU bursts with DSA was on the order of a few percent, just slightly higher than without DSA.

We propose a coordinated non-sensing medium access control (MAC) protocol in dynamic spectrum access networks namely distributed coordinated dynamic spectrum reservation (DCDSR) protocol which is not based on the cognitive radio technology. All primary users (PUs) and secondary users (SUs) have two transceivers operating in common control channel and licensed data channels to access control and data packets in the corresponding control and data frames, respectively. PUs will inform SUs which channels will be used in next data frame and then SUs reserve unused channels by contending with each other during contention interval (CI) in control frame. The available channels which can be reserved by SUs will depend on the channel usage of PUs and further affect the throughput of SUs. Whenever SU successfully reserve channel in CI, they will start access reserved channel in next data frame after the end of CI. This will cause the wasted idle time for those SUs which have successfully reserved channel whenever the CI doesn't finish. SU which couldn't successfully reserve channel in current control frame should try to reserve again in next control frame. Thus, the duration of CI will affect the delay and wasted idle time of SUs. We analyze and simulate the performance of throughput, delay and wasted idle time in DCDSR. The analytical and simulation results show that the proposed DCDSR performs very well.

In recent year, the most emerging and growing field of research and development is “Internet of Things” (IoT). This is due to advancement in wireless sensor network (WSN) which operate in the unlicensed industrial, scientific and medical (ISM) spectrum band. However, many wireless technologies operate in the same unlicensed spectrum, make it overcrowded and hence resulted in spectrum scarcity among those bands, the performance of WSN will degrade as their popularity increases. According to FCC report, most of the licensed spectrum is underutilized, sharing of underutilized licensed spectrum among unlicensed devices is a promising solution to the spectrum scarcity issue. Cognitive Radio (CR) is one of the capable technology that allows sensor nodes (as a Secondary Users (SUs)) to detect and use the underutilized licensed spectrum temporarily when Primary Users (PUs) not using it. With recent advances in Cognitive Radio (CR) technology, possible to apply the Dynamic Spectrum Access (DSA) model in WSNs to get access to underutilized licensed spectrum, possibly with better propagation characteristics, but as the existing protocols and algorithms developed for CRNs and WSNs are not directly applicable to CR-based WSNs and required new protocols. In this paper, we present a survey on the novel design of CR-based MAC, identify the main advantages and challenges of using CR technology, and compare the different method of improving energy efficiency. We believe that CR-WSN is the next-generation WSN. In this paper, we also discussed the open issues to motivate new research interest in this field.

Dynamic spectrum access and cognitive radio are emerging technologies to utilize the scarce frequency spectrum in an efficient and opportunistic manner. Cognitive radio, built on software defined radio, is an intelligent radio technology that updates its operating parameters to locate the unused spectrum segments. To assign these vacant bands to unlicensed users without causing harmful interference to licensed users, a novel approach is proposed in this article based on fuzzy logic. Two different fuzzy inference system models i.e. Mamdani and Sugeno systems are developed that compute spectrum access decision based on the secondary user parameters such as signal strength, distance between the primary and secondary user, spectrum utilization efficiency and degree of mobility. 81 fuzzy rules are used to obtain the output of proposed system stating the possibilities of allotment of white spaces to secondary users.

Cognitive radio technologies have become a promising approach to increase the efficiency of spectrum utilization. Although cognitive radio has been intensively studied in recent years, only a few works have discussed security aspects. In this paper, we focus on the jamming attack, one of major threats to cognitive radio networks, where a malicious user wants to jam the communications of secondary users by injecting interference. Aware of the absence of several primary users and the presence of a malicious user, a secondary user can allocate power to those fallow bands with a randomized strategy, in hope of alleviating the damage caused by the malicious user. We model this scenario into a two-player zero-sum game, and derive its unique Nash Equilibrium under certain conditions using the Colonel Blotto game approach, which provides a minimax strategy that the secondary user should adopt in order to minimize the worst-case damage caused by the malicious user. Simulation results are presented to verify the performance.

Over the past few years there has been a growing demand for radio resources and at the same time these resources are under utilized due to static spectrum allocation techniques. Dynamic spectrum access (DSA) has been thought of as a solution that would satisfy both the growing demand for radio resources and to efficiently utilize the spectrum. The radio devices that have the capability to dynamically sense the spectrum and access the under utilized bands are called cognitive radios (CR). There are two broad classes of users in CR, the primary user is a licensed user of a particular radio frequency band and the secondary users are unlicensed users who cognitively operate without causing harmful interference to the primary user. In this paper we consider a denial attack on centralized DSA networks where a malicious secondary user masquerades as a primary user and effectively shuts off access to all other secondary users. Note that this problem is unique to CR due to the distinction between primary and secondary users. We propose a public key cryptography based primary user identification mechanism that prevents malicious secondary users from masquerading as primary users. We show that the proposed identification mechanism and the associated key management are computationally light weight. We also discuss some advantages and limitations of the proposed identification mechanism.