SpecEES: Collaborative Research: Study of the Tradeoff between Spectrum Allocation Efficiency and Operation Privacy in Dynamic Spectrum Access Systems

List of personnel

Principal Investigators: Xiaojiang Du, Principal Investigator (Temple University); Jie Wu, Co-Principal Investigator (Temple University); Yaling Yang, Principal Investigator (Virginia Tech);

Vision

This project has two thrusts. In thrust #1, we focus on the study of joint efficient and secure designs for centralized DSA. Centralized DSA systems are the designs where both SUs and IUs only interact with a central entity. In thrust #2, we focus on the study of joint efficient and secure designs for distributed DSA systems. Distributed DSA systems are the designs where SUs and/or IUs exchange information among themselves to facilitate spectrum allocation in a DSA system.

Specific Objectives

Different spectrum allocation schemes in DSA system can cause different levels of exposure of sensitive incumbent/secondary user information. Thus, our study will focus on the following two thrust areas based on the two major design approaches for DSA spectrum allocation.

Thrust 1:Study of efficient and secure spectrum allocation in centralized DSA designs

In this thrust, we will focus on the study of joint efficient and secure designs for centralized DSA systems. Centralized DSA systems are the designs where both SUs and IUs only interact with a central entity, which will be referred as SAS (Spectrum Access System) in this proposal. SUs and IUs have no interactions among themselves in this type of designs. In this thrust, we will first identify the privacy and security threats in different types of centralized designs. Specifically, we will consider attack cases that compromise SAS or/and IUs so that they become threats to sensitive IU/SU information. Then, we will exam and design different approaches to address these threats and identify these approaches’ limitations and advantages. Finally, we will explore dynamic and mixed strategies that can leverages different approaches’ advantages while avoiding their pitfalls based on the variations in system requirements and user status.

Thrust 2:Study of efficient and secure spectrum allocation in distributed DSA designs

In this thrust, we will focus on the study of joint efficient and secure designs for distributed DSA systems. Distributed DSA systems are the designs where SUs and/or IUs exchange information among themselves to facilitate spectrum allocation in a DSA system. From performance point of view, distributed designs can make DSA system more scalable and robust since it reduces the workload of a central SAS. It may evenly completely eliminate the needs for a centralized coordination system, which is potentially the central point of failure. However, distributed design also introduces unique privacy and security challenges since the information exchanged among the users may inadvertently reveal sensitive information of these 2 users to untrusted other users or expose the system to threats of cheating where some users may lie in information exchange. In this thrust, we will explore approaches to solve these issues. We will focus on making sure our solution will not hurt the efficiency of the distributed system design while protecting the privacy and trustworthiness of the information exchange.

Major Activities

In this project, we jointly study privacy and efficiency in dynamic spectrum access (DSA). We develop new techniques to protect IU and SU operation privacy while still ensuring efficient spectrum allocation.

The major activities are summarized below.

  1. We study co-existing of Wi-Fi and LTE-U, and we propose a direct mechanism and an indirect mechanism for Wi-Fi and LTE-U to communicate with each other, which can achieve efficient and fair usage of wireless spectrum. Under the indirect communication mechanism, the AP of one Wi-Fi network first talks to the AP of the LTE provider’s Wi-Fi network, which then talks to the and LTE provider’s LTE BS. We formulate a constraint optimization problem, and the objective is to maximum the total amount of data transmitted by Wi-Fi and LTE networks.

  2. In this work, we study efficient utilization of spectrum resources in vehicular networks. We develop a cloud radio access network (C-RAN)-based vehicular network architecture, named C-VRAN, which can facilitate efficient spectrum usage and management for vehicular networks. We also propose a discrete cosine transform (DCT)-based data compression scheme for C-VRAN, which can increase the data transmission and spectrum efficiency.

  3. Load Based Equipment (LBE) mechanism is a category of Listen-Before-Talk (LBT) protocol adopted by LTE to access unlicensed channels to realize fair coexistence between LTE and Wi-Fi networks. However, most LBE optimization methods fix Channel Occupation Time (COT) in LBE and neglect its influence on network throughput and fairness. In the work, we present an optimal COT adjustment method for the LBE mechanism to maximize the throughput of LTE while satisfying the LTE users’ data rate demands, which ensures the efficiency and fairness for LTE and Wi-Fi networks.

  4. In cooperative spectrum sensing, an SU makes a decision about the presence of the PU based on information from other SUs. The information used to make this decision follows different rules than other SUs' sensing information. Malicious SUs (MSUs) send false sensing information to other SUs so that they make wrong decisions about the spectrum status. As a result, an SU may transmit during the presence of the PU or may keep starving for the spectrum. Both consequences degrade the performance of CRNs. In this work, we study a reputation-based mechanism which can minimize the effects of MSUs on decision making in cooperative spectrum sensing. Some of the SUs are selected as distributed fusion centers (DFCs), that are responsible for making decisions about the presence of PU and informing the reporting SUs. A DFC uses weighted majority voting among the reporting SUs, where weights are normalized reputation.

  5. Cognitive radio (CR) technology is envisioned to use wireless spectrum opportunistically when the primary user (PU) is not using it. In cognitive radio ad-hoc networks (CRAHNs), the mobile users form a distributed multi-hop network using the unused spectrum. The qualities of the channels are different in different locations. When a user moves from one place to another, it needs to switch the channel to maintain a quality-of-service (QoS) required by different applications. In this work, we study the mobility patterns of users, predict their next locations and probabilities to move there based on its history to minimize the number of channel switches during a user’s movement.

  6. In dynamic spectrum access (DSA), secondary transmitters (SU-TX) should only be allowed to transmit on a licensed channel belonging to incumbent users (IU) when the signal-to-interference-noise ratio (SINR) requirements of both IUs and SUs can be satisfied at the same time. However, in many DSA systems, the location and interference level of an IU are often considered sensitive data that should not be revealed, making it very challenging to ensure the QoS of both the IU and SUs while protecting IU operation security. In this work, we design a novel distributed SU transmit power control algorithm to solve this challenge.

  7. Multipath transmission is considered one of the promising solutions to improve wireless resource utilization where there are several types of heterogeneous wireless networks around. Most scheduling algorithms rely on real-time network metrics, including delay, packet loss, and arrival rates, and achieve satisfying results in simulation or wired environments. However, the implicit premise of a scheduling algorithm may conflict with the characteristics of real heterogeneous wireless networks, which has been ignored in the past. This work analyzes the network metrics of three real heterogeneous wireless networks under different transmission rates. To make the results more convincing, we conduct experiments in various scenarios, including different locations, different times of the day, different numbers of users, and different motion speeds.

Publications

  1. Y. Lin, P. Qiu, Y. Yang, X. Du, and J. Wu, "Distributed and Secure Power Control for Secondary Users in Dynamic Spectrum Access," IEEE Transactions of Mobile Computing, major revision, Sept, 2021.

  2. X. Zhang, P. Dong, X. Du, Y. Zhang, H. Zhang, M. Guizan, "Study on Characteristics of Metric-aware Multipath Algorithms in Real Heterogeneous Networks, " accepted, to appear in IEEE Globecom 2021, Madrid, Spain, December 2021.

  3. R. Biswas and J. Wu, “Minimizing The Number of Channel Switches of Mobile Users in Cognitive Radio Ad-Hoc Networks”, J. Sens. Actuator Network. 2020, 9, 23.

  4. R. Biswas, J. Wu, X. Du, and Y. Yang, “Mitigation of the spectrum sensing data falsifying attack in cognitive radio networks”, Cyber Physical System, Published online: Sept. 3, 2020.

  5. Y. Su, X. Lu, L. Huang, X. Du, and M. Guizani, “A Novel DCT-based Compression Scheme for 5G Vehicular Networks”, IEEE Transactions on Vehicular Technology, Nov. 2019.

  6. Q. Wang, X. Du, Z. Gao, and M. Guizani, “An Optimal Channel Occupation Time Adjustment Method for LBE in Unlicensed Spectrum”, IEEE Transactions on Vehicular Technology, Volume: 68, Issue: 11, pp. 10943 – 10955, Nov. 2019, doi: 10.1109/TVT.2019.2940123

  7. K. Chi, X. Du, G. Yin, J. Wu, M. Guizani, Q. Han, and Y. Yang, "Efficient and Fair Wi-Fi and LTE-U Coexistence via Communications over Content Centric Networking", Future Generation Computer Systems, Volume 112, Pages 297-306, Nov. 2019.