Cognitive Radio Networking (CRN) has been a hot research area for years. Nevertheless, the lack of real-world implementations and deployments results in various critical issues bothering both researchers in academia and practitioners in industry, although the Cognitive Radio (CR) technology holds a strong promise of improving the network availability and performance. The research on Mobile Ad-hoc Network (MANET) is faced with a similar problem. In this project, we present our exploratory endeavor to demonstrate the benefits of integrating CRN and MANET in supporting real world social applications.

According to the typical commercialization and deployment procedures of high-tech products such as NFC wallet, the amount of new-technology-enabled mobile personal devices is usually growing much faster than that of the corresponding infrastructures. In other words, we will see a networking scenario where there exists CR-enabled personal devices but no CR-enabled infrastructure, and such a situation may be omnipresent and may last for a relatively long time. Motivated by this observation, we consider a hybrid network architecture, which consists of CR-enabled personal devices accessing the Internet via conventional APs or Cellular Base Stations over the busy unlicensed or underutilized licensed channels, and self-organizing in an ad-hoc manner to improve their own performance as well as that of the conventional network. Such an architecture is particularly suitable for many real world social applications because i) the opportunistic communication provided by the ad-hoc CRN is more appropriate for occasional or delay tolerant applications such as text based information sharing; and ii) multi hop communications via neighboring users to access the traditional infrastructure can effectively reduce interference and improve the spectrum utilization when applying power control and dynamic spectrum access.

This hybrid architecture has been studied without considering the social relationships among the personal devices. Nevertheless, personal devices such as smartphones and iPads are mainly utilized for social activities. Therefore we augment the hybrid architecture by making it social-aware, such that the stability of each link is determined by the social relationship between its two end points (users) as well as the CR channel availability and the human mobility. This architecture is drastically different than the one considered in general literature as the latter ignores the “similarity” and “betweenness” of social entities. In this project, we intend to investigate a number of challenging problems that play critical roles in enhancing the performance of social applications by exploiting the social-aware hybrid architecture to take advantage of the benefits brought by integrating CRN and MANET.

This project tackles the challenges to enable scalable HD video chat (Task I), to improve the performance of time-bounded information dissemination (Task II), and to enhance the privacy of information sharing among the CR-enabled devices (Task III). Moreover, we will exploit network formation games to construct social-application-aware network topologies and investigate capacity and impact on the performance of the three tasks mentioned above (Task IV). We will also study the impact of topology control on social behaviors and vice version, and its impact on Task I-III, under our social-aware hybrid architecture (Task V). Complementing our research activities is a validation plan consisting of testbed experiment, simulation study, and theoretical performance analysis (Task VI).

1. Task I -- Enable scalable HD video chat. Considering that cameras on current smartphones are ready for HD video shoting and users are expecting to enjoy HD video chats via their own portable devices, the PIs propose to investigate techniques to support cooperative uplink Internet transmissions via utilizing social-aware ad-hoc CRN so that the users can obtain sufficient uplink rate to support HD video chats.
2. Task II -- Time-bounded information dissemination.The PIs propose to exploit CRN and social relationships to investigate fast information dissemination for emergent applications and cost-efficient dissemination for delay tolerant applications.
3. Task III -- Information leakage reduction. In conventional routing paradigm for social networks, all the wireless users (some of them may be unwelcome) on the message transmission route can overhear and capture the user’s social information. In order to reduce the probability of information leakage during wireless transmissions, the PIs propose to study routing algorithms for two practical security requirements, namely Trusted Group Multicast and Confidential Unicast, by exploiting the flexibility provided by CRN.
4. Task IV -- Network formation.The PIs propose to model and employ the social relationships for ad hoc CRN network formation in order to reinforce the above three tasks. Network formation games will be formulated for target applications to improve the performance in terms of throughput, delay, and network capacity.
5. Task V -- Topology control for reliable CR transmissions. In order to improve the CR link stability and the network capacity, the PIs target on recasting the definition of stable links via introducing the social-relationship-based temporal constraint, and design topology control schemes by jointly considering human mobility and spectrum availability. The PIs also will investigate the impact of topology control on social activities.
6. Task VI -- Performance evaluation. The performance of the proposed techniques will be verified via testbed experiment, simulation study, and theoretical analysis.

Journal Papers:

1. Jianhui Huang, Shengling Wang, Xiuzhen Cheng, Min Liu, Zhongcheng Li, Baio Chen, Mobility-Assisted Routing in Intermittently Connected Mobile Cognitive Radio Networks. to appear in IEEE Transactions on Parallel and Distributed Systems.

   Conference Papers:

2. Xianfu Chen, Tao Chen, Wei Cheng, Honggang Zhang, Reciprocity Inspired Learning for Opportunistic Spectrum Access in Cognitive Radio Networks, in CROWNCOM 2013, Washington DC, July 8-10, 2013.
3. Tao Jing, Xuewei Cui, Wei Cheng, Shixiang Zhu, Yanhuo, Xiuzhen Cheng, “Enabling Smartphone Based HD Video Chats by Cooperative Transmissions in CRNs”, submitted
4. Tao Jing, Fan Zhang, Wei Cheng, Yan Huo, Xiuzhen Cheng, “Online Auction Based Relay Selection for Cooperative Communication in CR Networks”, submitted

1. GWU PhD students Miss Wei Li and Mr. Chunqiang Hu attended the 2nd WiFiUS meeting and the WiFiUS Summer School at RPI in August 12-16, 2013. They met Dr. Tao Chen, the Finnish collaborator of this project, and discussed our joint work.
2. Dr. Tao Chen, the Finnish collaborator, visited GWU in July 8-10, 2013. He and the two PIs of this project (Dr. X. Cheng and Dr. W. Cheng) had a few meetings to review the progress and discuss the collaborative research.
3. Dr. X. Cheng proposed SI on Performance Enhancement of CRN to Eurosip Journal on Wireless Communications and Networking.