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In multi-channel cognitive radio ad hoc networks (CRAHNs), packet fragmentation is impacted by new factors besides those in traditional wireless networks due to the unique CR functions. For example, spectrum handoff is the technique for a secondary user (SU) to continue its transmission when a primary user (PU) reoccupies its current transmitting c...
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Citations
... After rendezvous, the D2D pair exchange their channel information to form their common available channel list. If later the communication is interrupted by PUs, they can hop on to the next channel in the list and resume their transmission [13], [14]. ...
... To be specific, even if the eavesdropper luckily stays on a channel where its target user, or some user (or indiscriminate attack), is transmitting data, there is a certain probability the user not to transmit all frames of a packet on this channel. As illustrated in Fig. 4, if a PU starts its packet transmission during a SU's frame transmission in the same channel (say, channel 1), then, the SU pair switches to their next common available channel (say, channel 2) for the retransmission of the previously unsuccessful frame [14]. In this way, an eavesdropper may even hard to intercept all frames for a single packet. ...
... From Fig. 6, when there are more PUs in the system, the anti-eavesdrop rate increases, which validates our analysis. In addition, when the packet size expands, the anti-eavesdrop rate also increases which is easy to understand based on the handoff model [14]. However, a larger packet size also implies a higher BER and longer retransmit time, resulting in a lower throughput. ...
... We adopt the MAC model from [21], [22] for network coordination. Whenever a SU has a packet to send, it first senses the channel. ...
Cognitive Radio (CR) has garnered much attention in the last decade, while the security issues are not fully studied yet. Existing research on attacks and defenses in CR-based networks focuses mostly on individual network layers, whereas cross-layer attacks remain fortified against single-layer defenses. In this paper, we shed light on a new vulnerability in cross-layer routing protocols and demonstrate how a perpetrator can exploit this vulnerability to manipulate traffic flow around it. We propose this cross-layer attack in CR-based wireless mesh networks (CR-WMNs), which we call off-sensing and route manipulation (OS-RM) attack. In this cross-layer assault, off-sensing attack is launched at the lower layers as the point of attack but the final intention is to manipulate traffic flow around the perpetrator. We also introduce a learning strategy for a perpetrator, so that it can gather information from the collaboration with other network entities and capitalize this information into knowledge to accelerate its malice intentions. Simulation results show that this attack is far more detrimental than what we have experienced in the past and need to be addressed before commercialization of CR-based networks.
... In most cases, the rendezvous channel is not the desired fast channel. Then, the D2D pair needs to handoff [14] to the corresponding desired channel in order to transmit the higher priority data, which adds additional handoff delay [15]. ...
Device to device (D2D) communication is essential in Internet of things (IoT). Cognitive radio (CR)-enabled device is a promising technique to address D2D communications. Among all the functions supported in IoT, priority-based spectrum access is less investigated yet urgently desired in IoT. An important operation to achieve this capacity is channel hopping (CH) based rendezvous which allows two CR users to meet each other on a common available channel. Unfortunately, existing CH methods cannot help CR users achieve priority-based spectrum access due to various shortcomings. In this paper, we propose PCH, a priority-based spectrum access protocol for cognitive D2D, which can be integrated with any existing CH algorithm. PCH can support priority transmissions with a significantly reduced CH delay, as compared with non-priority transmissions. More importantly, PCH can work under practical scenarios such as the D2D both with priority packets, the D2D handoff, and the overhead/energy constraint IoT. The merits of PCH are proved theoretically and validated against extensive simulations. To the best of our knowledge, this is the first work that investigates priority communications in cognitive IoT.
... For a SU pair, after a successful rendezvous, they enter the data transmission phase. In existing CRNs, instead of the rendezvous channel, a common available channel with the best quality is usually chosen for the transmission in order to avoid potential collisions with PUs [17]- [19]. However, this step is not necessary in MWB-CRNs since we ask the listening SU to limit its hopping activity in the best suitable band which is dynamically changed with its status or service requirement (e.g., when the SU is in a low battery condition, it chooses a low frequency band; when it has a high data-rate application, it chooses a high frequency band). ...
Ideally, users in cognitive radio networks (CRNs) are capable of sensing and exploiting any potential transmission opportunities in the available spectrum band ranging from 30 KHz to 300 GHz. With the multiple-diverse-band spectrum, the network can provide more radio resources and capacity to a large number of CR users. However, the multiband scenario (e.g., TV band + 2/3G band + 4/5G band) also introduces significant challenges in channel rendezvous, a fundamental operation for users in CRNs to set up their communication link on a common channel. Existing studies on channel rendezvous suffer from unacceptable long delay and high energy consumption when applied to such scenarios. In this paper, we propose a two-dimensional heterogeneous rendezvous (2D-HR) protocol which can support multi-wideband CRNs (MWB-CRNs) with a significantly reduced rendezvous delay and energy consumption for various rendezvous scenarios, such as the pair-wise rendezvous, any-wise rendezvous, and multi-wise rendezvous. The proposed design also performs better than existing efforts even when dealing with traditional single-band rendezvous. The merits of 2D-HR are proved theoretically and validated against extensive simulations. To the best of our knowledge, this is the first work that addresses heterogeneous rendezvous in MWB-CRNs.
